EA041653B1 - METHOD FOR PURIFYING BIO-1,3-BUTANEDIOL FROM ENZYME BROTH - Google Patents

Description

The present invention relates to a process for purifying bio-1,3-butanediol from fermentation broth.

More specifically, the present invention relates to a process for purifying bio-1,3-butanediol from a fermentation broth, comprising the following steps: (a) subjecting the fermentation broth to separation;

(b) subjecting the product obtained in step (a) to treatment using ion exchange resins;

(c) subjecting the product obtained in step (b) to a first evaporation;

(d) subjecting the product obtained in step (c) to a second evaporation;

(e) subjecting the product obtained in step (d) to a third evaporation to obtain purified bio-1,3-butanediol.

Said purified bio-1,3-butanediol can be advantageously used for the production of bio-1,3-butadiene, which in turn can be advantageously used as a monomer or as an intermediate in the production of elastomers and (co) polymers.

Therefore, one additional object of the present invention is a process for the production of bio-1,3-butadiene from purified bio-1,3-butanediol obtained as described above, as well as the use of said bio-1,3-butadiene as a monomer or as an intermediate compounds in the production of elastomers and (co)polymers.

As it should also be noted, from the mentioned process for the production of bio-1,3-butadiene, in particular from the dehydration of bio-1,3-butanediol, other alkenols are also obtained, namely bio2-buten-1-ol (crotyl alcohol) , bio-3-buten-2-ol (methylvinylcarbinol), bio-3-buten-1-ol (allylcarbinol), more specifically bio-2-buten-1-ol (crotyl alcohol) and bio-3-butene -2-ol (methylvinylcarbinol), which, in addition to the production of bio-1,3-butadiene, can be advantageously used in the production of an intermediate, which in turn can be used in fine chemistry, agrochemistry, pharmaceutical chemistry or petrochemistry.

For the purposes of this specification and the following claims, the term bio-2-buten-1-ol (crotyl alcohol) refers to a mixture of cis and trans isomers, the cis isomer alone, and the trans isomer alone.

For example, bio-2-buten-1-ol (crotyl alcohol) can be used as a precursor for halides, crotyl esters or crotyl ethers, which in turn can be used, for example, as intermediates in the production of monomers, in fine chemistry (for example, for the production of sorbic acid, trimethylhydroquinone, crotonic acid, 3-methoxybutanol), agrochemistry, pharmaceutical chemistry.

Bio-3-buten-2-ol (methylvinylcarbinol) can be used as a solvent in fine chemistry, as a component in the modification of polymers such as, for example, polyolefins (as described, for example, in German patent DE 1908620).

Bio-3-buten-1-ol (allylcarbinol) can be used, for example, as a raw material in pharmaceutical chemistry, agrochemistry, perfume, resins. For example, the coupling reaction between bio-3-buten-1-ol (allylcarbinol) and aryl halides, catalyzed using palladium, produces aryl-substituted aldehydes, which can be used in pharmaceutical chemistry, for example, as folic acid antagonists.

Methods for purifying polyols are known in the art.

For example, US Pat. No. 6,361,983 relates to a process for isolating one or more polyols, in particular 1,3-propanediol (1,3-PDO), from a fermentation broth, comprising the following steps, in which (a) a base is added to the fermentation broth to increasing the pH value to more than 7; and (b) separating the polyol, in particular 1,3-propanediol, from the fermentation broth.

Polyols of particular interest are 1,3-propanediol, 1,4-butanediol, glycerol, ethylene glycol. Stage (b) isolation is carried out by evaporation, distillation, filtration, extraction or crystallization. Said method may further comprise the step of (c) removing precipitated solids that are present in the product obtained from step (b) by 1) filtration or centrifugation or 2) vacuum distillation. The referenced patent does not specifically mention 1,3-butanediol.

US Pat. No. 7,919,658 relates to a process for purifying bio-1,3-propanediol from a fermentation broth obtained from a microorganism capable of producing 1,3-propanediol, comprising the following steps in their order:

(a) subjecting the fermentation broth to filtration;

(b) subjecting the product obtained in step (a) to two purification steps by ion exchange, including (i) anion exchange and (ii) cation exchange, to remove ion impurities;

(c) subjecting the product obtained in step (ii) to chemical reduction; and (d) subjecting the product obtained in step (c) to at least two distillation processes,

- 1 041653 comprising at least two distillation columns, wherein one of said distillation columns removes molecules characterized by a boiling point greater than the boiling point of 1,3-propanediol, and the other removes molecules characterized by a boiling point lower than the boiling point 1,3-propanediol;

this yields a purified bio-1,3-propanediol having a total impurity concentration of less than about 400 ppm, an optical density in the 275 nm region of less than 0.075, and a b* color coordinate value (CIE L*a *b*) of less than about 0.15.

International patent application WO 2014/141780 relates to a method for isolating 1,4-butanediol (1,4-BDO) from a fermentation broth, which includes separating a liquid fraction enriched in 1,4-BDO from a solid fraction containing cells, removing water from said liquid fraction, removing salts from said liquid fraction and purifying 1,4-BDO. Said method includes various steps such as cells: removal (centrifugation and/or microfiltration and/or ultrafiltration);

water and light compounds: removal when using an evaporation system including a two- or three-effect evaporator;

salts: removal using nanofiltration and/or ion exchange resins and/or precipitation and/or crystallization.

As stated in the mentioned patent application, the method described in the mentioned document can be easily modified for the purpose of isolating 1,3-butanediol, however, no examples of this are presented.

US Patent Application US 2014/0275465 relates to a process for purifying 1,4-butanediol (1,4-BDO) comprising (a) subjecting the feedstock mixture to produce 1,4-BDO to distillation using a first distillation column to remove compounds characterized by a boiling point less than the corresponding temperature for 1,4-BDO, upon receipt of the first stream containing 1,4-BDO; and (b) subjecting said first stream containing 1,4-BDO to distillation using a second distillation column to remove compounds having a boiling point greater than the corresponding temperature for 1,4-BDO, to obtain a first stream of high boiling compounds, such in a manner to produce purified 1,4-BDO, wherein said purified 1,4-BDO is withdrawn from said second column in a lateral position.

1,3-butanediol is mentioned among the compounds that can be purified using the mentioned method, however, no examples of this are presented.

US Pat. No. 9,533,931 relates to a process for the production of 1,4-butanediol comprising the following steps, in which (a) an alkaline substance other than ammonia compounds and other than amine compounds is added to an aqueous solution containing 1,4-butanediol having its origin is a fermentative broth;

(b) carry out the distillation of the mixture obtained in stage (a); and (c) recovering the solution containing 1,4-butanediol from the vapor stream;

wherein, prior to the addition of said alkaline substance, said aqueous solution containing 1,4-butanediol originating from the fermentation broth is subjected to a nanofiltration step from which the permeate is recovered;

and/or ion exchange steps.

The purified 1,4-butanediol obtained is said to be advantageously used as a material for the production of polyester. However, the said methods for isolating and purifying 1,3-propanediol or 1,4-butanediol from the fermentation broth may present some difficulties. For example, the processes mentioned require purification steps using one or more distillation columns, resulting in extended process times and increased production costs.

In addition, even though it is possible, as it is said, to apply some of the mentioned methods also to the purification of 1,3-butanediol, one of the critical steps in the purification of 1,3-butanediol is distillation. Indeed, the presence in the fermentation broth of specific contaminants [e.g., 4-hydroxy-2-butanone (4-OH-2B)] that differ, even if only in concentration, from the corresponding contaminants present in fermentation broths for the production of other diols may stimulate the passage of uncontrolled reactions during the distillation itself.

In fact, as is known as described in, for example, Ichikawa N. et al., Catalysis Communications (2005), vol. 6, p. 19-22, 4-hydroxy-2-butanone (4-OH-2B) can dehydrate to form 3-buten-2-one (MVK) even at low temperatures (e.g.

- 2 041653

100-120°C), which is promoted by the presence of acid sites. The presence of a ketone during the distillation of a solution containing 1,3-butanediol can lead to the formation of ketal from the reaction between 1,3-butanediol and 3-buten-2-one (MVK), which contaminates fractions containing purified 1,3 -butanediol, and which, even if successfully removed, leads to the loss of part of the 1,3-butanediol and thus to a decrease in the yield for the process [as can be seen from (comparative) example 3, which is reported below]. In the case of distillation of said solution containing 1,3-butanediol under high vacuum, the formation of 3-buten-2-one (MVK) and thus the formation of ketal is inhibited, but for the same column used, this encourages an increase in the residence times of said solution in the distillation cube, which results in an increase in the amount of thermal decomposition products of 1,3-butanediol. [As can be seen from the (comparative) example 4 reported below].

Therefore, the Applicant has set himself the problem of finding a process for purifying bio-1,3-butanediol from fermentation broth that is capable of overcoming the drawbacks reported above.

As the Applicant has now established, by avoiding the prior art distillation steps and by using the first, second and third evaporation steps, the disadvantages discussed above can be overcome. In particular, Applicant has discovered a process for purifying bio-1,3butanediol from fermentation broth, comprising the following steps: (a) subjecting the fermentation broth to separation;

(b) subjecting the product obtained in step (a) to treatment using ion exchange resins;

(c) subjecting the product obtained in step (b) to a first evaporation;

(d) subjecting the product obtained in step (c) to a second evaporation;

(e) subjecting the product obtained in step (d) to a third evaporation to obtain purified bio-1,3-butanediol.

By using the above method, many advantages are achieved. For example, said method makes it possible to avoid both the formation of ketal as a result of the reaction between bio-1,3-butanediol and bio-3-buten-2-one (MVK), and the thermal decomposition of bio-1,3-butanediol, which in the result is an increase in yield for the process. In addition, by avoiding the use of distillation columns, both the system and the process are simplified, resulting in savings both economically and in terms of process times.

In addition, said process makes it possible to obtain purified bio-1,3-butanediol, which can be advantageously used for the production of bio-1,3-butadiene, which in turn can be advantageously used as a monomer or as an intermediate in the production of elastomers and (co)polymers.

Therefore, one additional object of the present invention is a process for the production of bio-1,3-butadiene from purified bio-1,3-butanediol obtained as described above, as well as the use of said bio-1,3-butadiene as a monomer or as an intermediate compounds in the production of elastomers and (co)polymers.

Therefore, an object of the present invention includes a process for purifying bio-1,3-butanediol from a fermentation broth, comprising the following steps: (a) subjecting the fermentation broth to separation;

(b) subjecting the product obtained in step (a) to treatment using ion exchange resins;

(c) subjecting the product obtained in step (b) to a first evaporation;

(d) subjecting the product obtained in step (c) to a second evaporation;

(e) subjecting the product obtained in step (d) to a third evaporation to obtain purified bio-1,3-butanediol.

For the purposes of this specification and the following claims, definitions of numerical ranges will always include endpoints unless otherwise stated.

For the purposes of this specification and the following claims, the term containing also includes terms essentially consisting of or consisting of.

For the purposes of the present specification and the following claims, the term purified bio-1,3-butanediol refers to the preparation at the end of the process according to the present invention, i.e. at the end of step (e) of the third evaporation, an aqueous solution in which bio-1,3-butanediol is present at a concentration greater than or equal to 85% by weight, preferably greater than or equal to 90% by weight, based on the total weight of said aqueous solution ;

water is present at a concentration less than or equal to 15% by weight, preferably less than or equal to 8% by weight, based on the total weight of said aqueous solution;

any organic impurities [for example, acids, 4-hydroxy-2-butanone (4-OH-2B)] may be present in an amount less than or equal to 2 wt.%, preferably in an amount less than or equal to 1 wt. %, based on the total weight of said aqueous solution;

any products derived from the degradation of bio-1,3-butanediol [e.g. 3-buten-2-one,

2-buten-1-ol (cis and trans isomers), 3-buten-1-ol, 3-buten-2-ol] may be present in an amount less than or equal to 0.01% by weight, preferably less than or equal to 0.005 wt.%, based on the total weight of the mentioned aqueous solution;

any sugars (eg glucose) may be present in an amount less than or equal to 0.001 g/l, preferably less than or equal to 0.0005 g/l.

For the purposes of this specification and the following claims, the term bio-1,3-butanediol refers to the synthesis of said 1,3-butanediol from one or more biological species or strains of living organisms, including preferably strains of bacteria, yeasts, fungi and others. organisms.

In general, said fermentation broth may be produced from the fermentation of commercially available sugars, or may be produced from renewable sources when operated in a suitable culture medium in the presence of at least one microorganism genetically modified to produce 1,3-butanediol. In general, said microorganism is genetically modified by introducing one or more exogenous genes that encode compounds belonging to the enzymatic route for the production of 1,3-butanediol. Optionally, said microorganism may further include gene disruption to optimize carbon flow through the desired 1,3-butanediol production route. The renewable sources mentioned are generally biomasses of plant origin: for these purposes it is possible to use, for example, sugarcane and beets as sources of sugar (e.g. glucose, arabinose, xylose, sucrose) or corn and potatoes as a source of starch and, thus dextrose. However, looking to the future, non-edible biomasses such as corn stalks, cereal straw, arundo, thistle stalks, guayule bagasse and the like are also of increased interest, which can provide sugars from the breakdown of cellulose and hemicellulose. In general, plant biomass is subjected to chemical and/or enzymatic hydrolysis to produce substrates that can subsequently be biocatalytically processed to produce chemicals of interest. Said substrates include mixtures of carbohydrates as well as aromatic compounds and other products derived from cellulose, hemicellulose and lignin present in the biomass. The carbohydrates obtained from the hydrolysis of said biomass are a mixture enriched in sugars containing 5 and 6 carbon atoms and include, for example, sucrose, glucose, xylose, arabinose, galactose, mannose and fructose, which will be used in fermentation. Additional details regarding the above methods for the synthesis of 1,3-butanediol can be found, for example, in US patent applications US 2010/330635, US 2012/329113, US 2013/066035, US 2013/109064, incorporated herein by reference. .

To purify bio-1,3-butanediol from a fermentation broth, it is first desirable to separate the cell biomass as well as cell debris and contaminants having a relatively high molecular weight from said fermentation broth. The state of the art knows methods suitable for use in separating cell biomass and other particulate compounds from liquids, such as filtration and centrifugation.

In one preferred embodiment of the present invention, said step (a) may include the following steps:

(a _1a ) microfiltration; and (a ₂ ) nanofiltration.

In one further preferred embodiment of the present invention, said step (a) may include the following steps:

(a _1b ) centrifugation; and (a ₂ ) nanofiltration.

In one preferred embodiment of the present invention, said microfiltration step (a _1a ) can be carried out using membranes having an average pore diameter in the range of 0.01 to 1.0 µm, preferably in the range of 0.02 to 0.08 µm.

In one preferred embodiment of the present invention, said microfiltration step (a _1a ) can be carried out in operation at a transmembrane pressure in the range of 0.1 to 8 bar, preferably in the range of 1 to 5 bar, said transmembrane pressure being defined as the average pressure between the pressure measured upstream of the microfiltration module and the pressure measured downstream of the microfiltration module.

In one preferred embodiment of the present invention, said microfiltration step (a _1a ) can be carried out at a temperature in the range of 20 to 90°C, preferably in the range of 40 to 70°C, more preferably at a fermentation temperature.

- 4 041653

In one preferred embodiment of the present invention, said microfiltration step (a _1a ) can be carried out using ceramic membranes that are submersible in either a cross-flow configuration or a dynamic cross-current configuration, or using flat or hollow fiber polymer membranes that are submersible. or in cross current configuration.

Examples of membranes that can be used for the purposes of the present invention and are commercially available are Hydrosart® Microfiltration Cassettes from Sartorius or Ceram inside® from Tami or Schumasiv™ or Membralox® from Pall, or Microza products from Asahi Kasei Corporation.

At the end of said microfiltration step (a _1a ), a permeate containing bio-1,3butanediol, water and residual impurities (eg sugars, other organic impurities, salts) is obtained, which can be sent to the nanofiltration step (a ₂ ) as described above. , or directly to stage (b) processing using ion exchange resins, as well as a retentate containing cell biomass and any cell debris. Said retentate may be dried and disposed of in a landfill or incinerated, or may be sent directly to a water treatment plant.

In one preferred embodiment of the present invention, said centrifugation step (a _1b ) can be carried out at a temperature in the range of 20 to 90°C, preferably in the range of 25 to 70°C, more preferably at room temperature (25°C).

In one preferred embodiment of the present invention, said centrifugation step (a _1b ) can be carried out in operation at a centrifuge feed rate in the range of 50 to 1000 l/h, preferably in the range of 90 to 500 l/h.

In one preferred embodiment of the present invention, said centrifugation step (a _1b ) can be carried out at a rotation speed in the range of 2000 to 50000 rpm, preferably in the range of 3000 to 9000 rpm.

For the purposes of the present invention, said centrifugation step (a _1b ) may be carried out in any type of centrifuge known in the art; in particular, a plate centrifuge including automatic panel ejection model CA21-P from Andritz was used.

At the end of said centrifugation step (a _1b ), a lighter aqueous phase (supernatant) containing bio-1,3-butanediol, water and residual impurities (eg sugars, other organic impurities, salts) is obtained, which can be sent to the step ( a ₂ ) nanofiltration as described above, or directly to stage (b) processing using ion exchange resins, as well as a second heavier aqueous phase (precipitate) containing cellular biomass and any cellular debris. Said second aqueous phase (precipitate) may be dried and disposed of in a landfill or incinerated, or may be sent directly to a water treatment plant.

In one preferred embodiment of the present invention, said nanofiltration step (a2) can be carried out using nanofiltration membranes having a nominal molecular weight cutoff (MWCO) in the range of 100 to 500 daltons, preferably in the range of 120 to 400 daltons.

In one preferred embodiment of the present invention, said nanofiltration step (a ₂ ) can be carried out using nanofiltration membranes having a maximum operating temperature in the range of 15 to 100°C, preferably in the range of 20 to 80°C.

In one preferred embodiment of the present invention, said nanofiltration step (a ₂ ) can be carried out in operation at a transmembrane pressure in the range of 10 to 50 bar, preferably in the range of 20 to 40 bar, said transmembrane pressure being defined as the mean pressure between the pressure measured upstream of the nanofiltration module and the pressure measured downstream of the nanofiltration module.

The aforementioned hydrophilic nanofiltration membranes may be in the form of flat sheets, hollow fibers, tubular membranes, roll type membranes, or other favorable forms.

Nanofiltration membranes that can advantageously be used for the purposes of the present invention are products known under the trade names DK Series from GE Power & Water or SR3D™ Membrane from Koch Membrane Systems.

At the end of said stage (a ₂ ) of nanofiltration, a permeate containing bio-1,3butanediol, water and residual impurities (for example, salts, acids) is obtained, which is sent to stage (b) of processing using ion exchange resins, as well as a retentate containing compounds , characterized by large steric hindrances (for example, proteins, divalent salts). Said retentate can be sent directly to a water treatment plant.

In one preferred embodiment of the present invention, said step (b) of the treatment using ion exchange resins may include two steps:

(b ₁ ) an anion exchange step;

(b ₂ ) cation exchange step.

In one preferred embodiment of the present invention, said step (b1) can be carried out using a column containing a weak anionic resin.

Weak anionic resins that can advantageously be used for the purposes of the present invention are products known under the trade names Dowex™ Monosphere™ 77 from Dow Chemical or Diaion® WA30 from Mitsubishi Chemical Corporation.

In one preferred embodiment of the present invention, said step (b ₂ ) can be carried out using a column containing a strong cationic resin.

Strong cationic resins that can be advantageously used for the purposes of the present invention are products known under the trade names Dowex™ Monosphere™ 88 from Dow Chemical or Amberlite™ MB 150 from Rohm & Haas Resins.

In one preferred embodiment of the present invention, said steps (b1) and (b ₂ ) can be carried out at a temperature in the range of 15 to 50°C, preferably in the range of 20 to 45°C.

In one preferred embodiment of the present invention, said steps (b1) and (b ₂ ) can be carried out at a flow rate [liters of the product obtained in step (a) per hour] in the range of 2 to 4 OC/h, preferably in the range of 2.5 to 3.5 OC/h, (OC-bed volume=resin volume per column).

In one preferred embodiment of the present invention, the product obtained from said steps (b1) and (b ₂ ) may have a residual conductivity in the range of 0.1 to 100 µS/cm, preferably in the range of 0.5 to 15 µS/ cm.

In one preferred embodiment of the present invention, the product obtained in step (a) may be fed to step (b1) and subsequently to step (b2) or may be fed to step (b2) and subsequently to step (b1).

At the end of said step (b) of treatment using ion exchange resins, an aqueous solution is obtained containing bio-1,3-butanediol, water, light organic compounds (e.g. ethanol), heavy organic compounds [e.g. 4-hydroxy-2-butanone ( 4-OH-2B)], unconverted sugars and any salts not removed. Said aqueous solution is sent to step (c) of the first evaporation.

At the end of said step (b), the columns containing the ion exchange resins used in the above steps (b1) and (b ₂ ) are regenerated using acid or base solutions in an operation according to methods known in the state of the art.

In one preferred embodiment of the present invention, said first evaporation step (c) may be carried out at a temperature in the range of 30 to 100°C, preferably in the range of 40 to 70°C.

In one preferred embodiment of the present invention, said first evaporation step (c) can be carried out at a pressure in the range of 5 to 100 mbar, preferably in the range of 10 to 80 mbar.

For the purposes of said step (c), any type of evaporator known in the art can advantageously be used. Specific examples of evaporators which can be advantageously used are rotary evaporators, natural circulation evaporators in which evaporation is stimulated by movements caused by simply boiling, vapor space evaporators, evaporators in which evaporation is stimulated by forced circulation, for which speed and turbulence are increased by using a circulation pump (forced circulation evaporators), ME-EV evaporators (multi-effect evaporators), single-stage or multi-stage evaporators, single-effect evaporators, STV evaporators (vertical evaporators with internal heating chamber), LTV evaporators (vertical evaporators with long tube type), basket type evaporators, horizontal tube evaporators, falling film evaporators, spreading film evaporators, flash evaporators, multi-stage evaporators m instant effervescence and the like. Preferably, in said step (c), an ME-EV (multi-effect evaporator) evaporator can be used.

At the end of said step (c) of the first evaporation, a concentrated solution is obtained containing bio-1,3-butanediol, water, heavy organic compounds [e.g. 4-hydroxy-2-butanone

- 6 041653 (4-OH-2B)], unconverted sugars and any salts not removed, which are sent to stage (d) of the second evaporation, as well as an aqueous phase containing mainly water and trace amounts of ethanol and bio- 1,3-butanediol, which can be recycled to one of the following stages: (a _1a ) microfiltration, (a _1b ) centrifugation, (a ₂ ) nanofiltration, (b) processing using ion exchange resins. Alternatively, said aqueous phase may be sent directly to a water treatment plant.

In one preferred embodiment of the present invention, said second evaporation step (d) may be carried out at a temperature in the range of 30 to 150°C, preferably in the range of 40 to 130°C.

In one preferred embodiment of the present invention, said second evaporation step (d) can be carried out at a pressure in the range of 1 to 100 mbar, preferably in the range of 8 to 80 mbar.

For the purposes of the above step (d), any type of evaporator known in the art can advantageously be used. Specific examples of evaporators which can advantageously be used are the corresponding evaporators reported above. Preferably, in said step (d), a spread film evaporator may be used.

At the end of said second evaporation step (d), a concentrated solution is obtained containing bio-1,3-butanediol, water and trace amounts of heavy organic compounds [for example, 4-hydroxy-2-butanone (4-OH-2B)], sugars, unconverted and any salts not removed, which are sent to stage (e) of the third evaporation, as well as an aqueous phase containing mainly water, organic compounds characterized by a boiling point lower than the corresponding temperature for bio-1,3-butanediol , and trace amounts of bio-1,3-butanediol, which can be sent directly to a water treatment plant.

In one preferred embodiment of the present invention, said third evaporation step (e) may be carried out at a temperature in the range of 30 to 150°C, preferably in the range of 40 to 130°C.

In one preferred embodiment of the present invention, said third evaporation step (e) can be carried out at a pressure in the range of 5 to 100 mbar, preferably in the range of 8 to 80 mbar.

For the purposes of the above step (e), any type of evaporator known in the art can advantageously be used. Specific examples of evaporators which can advantageously be used are the corresponding evaporators reported above. Preferably, in said step (e), a spread film evaporator may be used.

At the end of said step (e) of the third evaporation, two phases are obtained:

an aqueous phase containing purified bio-1,3-butanediol;

an organic phase containing any organic compounds having a boiling point greater than the corresponding temperature for bio-1,3-butanediol and trace amounts of crude bio-1,3-butanediol, unconverted sugars and any salts not removed.

Further details regarding the types of evaporators used can be found, for example, in Process Heat Transfer, Donald Q. Kern, McGraw-Hill (1950), Chapter 14, Evaporator, p. 375-510; Perry's Chemical Engineers' Handbook, McGraw-Hill (7th ed., 1997), Section 11, p. 108-118.

As it should be noted, in said stages (c), (d) and (e) of evaporation, the evaporation rate will be at a maximum at the beginning of evaporation and will decrease over time until it is equal to zero at the end of evaporation.

According to the above statement of the invention, the bio-1,3-butanediol recovered at the end of said step (e) can advantageously be used in a process for the production of bio-1,3-butadiene. Therefore, one additional object of the present invention is a process for the preparation of bio-1,3-butadiene, which includes the steps at which the mixture (i) containing bio-1,3-butanediol obtained in accordance with the method described above is fed into the first reactor containing at least one dehydration catalyst, to obtain a stream (ii) containing alkenols, water and optional impurities that have not been converted, and/or bio-1,3-butanediol that has not been converted leaving said first reactor;

optionally feeding said stream (ii) to the first purification section to obtain a stream (iii) containing alkenols, water and optional impurities;

a stream (iv) containing water and optional impurities and/or unconverted bio-1,3-butanediol; and optionally a stream (v) containing impurities;

feeding said stream (iii) and/or said stream (iv) into a second reactor containing

- 7 041653 at least one dehydration catalyst, to obtain a stream (vi) containing bio-1,3-butadiene, water and optional impurities and/or alkenols that have not been converted, leaving said second reactor;

feeding said stream (vi) to a second purification section to obtain a stream (vii) containing pure bio-1,3-butadiene;

a stream (viii) containing water and optionally unconverted alkenols; and optionally a stream (ix) containing impurities.

For the purposes of the present invention, said process for the preparation of bio-1,3-butadiene can advantageously be carried out in accordance with the description of the invention in US patent application US 2017/313633 in the name of the applicant, incorporated herein by reference.

However, as it should be noted, said bio-1,3-butanediol can advantageously be used to prepare bio-1,3-butadiene in accordance with any of the methods known in the state of the art, when carried out in the operation in accordance with the descriptions inventions, for example, in international patent application WO 2015/173780, in US patent applications US 2018/0002250, US 2018/0002249 in the name of the applicant, incorporated herein by reference.

In accordance with the above statement of the invention, one additional object of the present invention is also the use of said bio-1,3-butadiene as a monomer or as an intermediate in the production of elastomers and (co)polymers.

The present invention will now be illustrated in more detail using one embodiment and with reference to FIG. 1 and 2, which are reported below.

The method according to the present invention can be implemented as shown, for example, in FIG. 1.

In this context, a fermentation broth (1) containing bio-1,3-butanediol and water, said fermentation broth preferably derived from the fermentation of biomass-derived sugars, is sent to a microfiltration step to obtain a permeate (2) containing bio-1 ,3butanediol, water and residual impurities (for example, sugars, other organic impurities, salts), which are sent to the nanofiltration stage, as well as a retentate (not shown in Fig. 1) containing cellular biomass and any cellular debris that can be dried and disposed of in a landfill or incinerated, or may be sent directly to a water treatment plant. At the end of the mentioned nanofiltration stage, a permeate (3) is obtained containing bio-1,3butanediol, water and residual impurities (for example, salts), which is sent to the processing stage using ion exchange resins, as well as a retentate (not shown in Fig. 1), containing compounds characterized by high steric hindrance (eg proteins, divalent salts), which can be sent directly to the water treatment plant. Thus, said permeate (3) is subjected to a treatment step using ion exchange resins, namely a treatment in a column containing a weak anionic resin followed by a treatment in a column containing a strong cationic resin, or vice versa (not shown in Fig. 1) with obtaining an aqueous solution (4) containing bio-1,3-butanediol, water, light organic compounds (for example, ethanol), heavy organic compounds [for example, 4-hydroxy-2-butanone (4-OH-2B)], sugars , not subjected to transformation, and any salts not removed. Said aqueous solution (4) is sent to the first evaporation stage to obtain a concentrated solution (5) containing bio-1,3-butanediol, water, heavy organic compounds [for example, 4-hydroxy-2-butanone (4-OH-2B) ], unconverted sugars, and any salts not removed, which are sent to the second evaporation stage, and an aqueous phase (not shown in Figure 1) containing mainly water and trace amounts of ethanol and bio-1,3-butanediol , which can be sent for recycling to one of the following stages:

(a _1a ) microfiltration (4c);

(a ₂ ) nanofiltration (4b);

(b) treatments using ion exchange resins (4a) (shown in broken lines in Fig. 1).

From said second evaporation step, a concentrated solution (6) is obtained containing bio-1,3-butanediol, water and trace amounts of heavy organic compounds [e.g. 4-hydroxy2-butanone (4-OH-2B)], unconverted sugars , and any non-removed salts, which is sent to the third evaporation stage, as well as an aqueous phase (not shown in Fig. 1) containing mainly water, organic compounds characterized by a boiling point lower than the corresponding temperature for bio-1,3 -butanediol, and trace amounts of bio-1,3-butanediol, which can be sent directly to the water treatment plant. From the said third evaporation step, two phases are obtained:

an aqueous phase (7) containing purified bio-1,3-butanediol; and an organic phase (not shown in Figure 1) containing any organic compounds having a boiling point greater than the corresponding temperature for bio-1,3-butanediol and trace amounts of crude bio-1,3- butanediol, unconverted sugars and any non-removed salts.

In FIG. 2 shows a form of embodiment of the process for preparing bio-1,3-butadiene according to the present invention.

In FIG. 2 mixture (i) containing bio-1,3-butanediol obtained in accordance with the object of the method of the present invention is fed into the first reactor containing at least one dehydration catalyst, obtaining a stream (ii) containing alkenols, water and optionally impurities and/or unconverted bio-1,3-butanediol leaving said first reactor; said stream (ii) is fed to the first purification section to obtain a stream (iii) containing alkenols, water and optional impurities, a stream (iv) containing water and optional impurities and/or unconverted bio-1,3butanediol (not shown in Fig. 2) and a stream (v) containing impurities (not shown in Fig. 2); said stream (iii) is fed to a second reactor containing at least one dehydration catalyst to obtain a stream (vi) containing bio-1,3-butadiene, water and optionally unconverted impurities and/or alkenols leaving said the second reactor, which is fed into the second purification section to obtain a stream (vii) containing pure bio 1,3-butadiene, a stream (viii) containing water and optionally unconverted alkenols (not shown in Fig. 2) and optionally a stream (ix) containing impurities (not shown in Fig. 2).

For a better understanding of the present invention and to put it into practice, illustrative non-limiting examples thereof are reported herein below.

Example 1 Purification of bio-1,3-butanediol.

For these purposes, a model fermentation broth was used containing bio-1,3-butanediol (for simplicity, hereinafter referred to as 6uo-1,3-BDO) and characterized by an average composition, which is reported in table. 1.

Table 1

Composition of a model fermentation broth containing 6uo-1,3-BDO

Connections * Quantity Bio-1,3-BDO (g/l) 70-95 Cell biomass (g/l) 20 By-products (ethanol, acetic acid, 4-hydroxy-2-butanone, proteins) (g/l) 20-35 Residual salts (g/l) < 10 Residual glucose (g/l) < 1

* The rest is water.

The level of sugars and organic acids, as well as bio-1,3-butanediol in dilute solutions (i.e. in aqueous solutions characterized by a concentration of 1,3-BDO<150 g/l) was determined using high performance liquid chromatography (HPLC) using a Waters 2690 Alliance Modular System Chromatograph equipped with a binary pump, degasser, autosampler and oven compartment. The column used is a Phenomenex ROA-Organic Acid H ⁺ product, having dimensions of 300x7.8 mm, at 45°C in isocratic mode using an aqueous solution of sulfuric acid (H ₂ SO ₄ ) at 0.005 N. with a flow rate of 0.6 ml/min. Two detectors were used: a Waters 2487 optical absorption detector (DAD) at two wavelengths in the UV/visible range and a Waters 2410 refractive index detector (RID).

The fermentation broth reported in Table. 1 were divided into three separate batches, ie. batch 03, batch 04 and batch 05, and purified by performing the operation as follows.

Removal of cell biomass as a result of microfiltration.

To remove cell biomass, the fermentation broth, i.e. batch 04 and batch 05 were sent to a microfiltration module comprising a Membralox® ceramic membrane in a crossflow configuration having an average pore diameter of 0.05 µm. Said microfiltration module was subdivided into 19 channels, characterized by a diameter of 6 mm and a total filtration area of 0.36 m ² . During the test, an attempt was made to maintain a current velocity of 4-5 m/s in the membrane in such a way as to limit fouling and to achieve a concentration factor [volume concentration ratio (VCR)], defined as the ratio between the volume of fermentation broth supplied at the inlet and the resulting volume of permeate, constituting more than 5, preferably in the range from 6 to 10: additional data regarding the operating conditions in which the microfiltration was carried out, reported in table. 2. At the end of microfiltration, a permeate containing 6uo-1,3-BDO, water and residual impurities (e.g., sugars, other organic impurities, salts) was obtained, which was sent to the nanofiltration module in the operation as described below, and also retentate containing cell biomass and any cell debris that was dried and disposed of at a landfill: the amount of 6uo-1,3-BDO compound recovered is also reported in Table 1. 2.

Removal of cell biomass by centrifugation.

To remove cell biomass, the fermentation broth, i.e. Batch 03 was centrifuged using a plate centrifuge including automatic panel ejection model CA21-P (Andritz) when operating under the following conditions:

feed rate: 100 l/h;

panel ejection interval: 5 min;

ejection method: water ejection;

rotation speed: 8000 rpm;

temperature: room temperature (25°C).

Additional data regarding the operating conditions under which centrifugation was performed is reported in Table 1. 2. At the end of the centrifugation, a first lighter aqueous phase (supernatant) containing 6uo-1,3-BDO, water and residual impurities (e.g. sugars, other organic impurities, salts) was obtained, which was sent to the nanofiltration module when performing the operation in as described below, as well as a second heavier aqueous phase (precipitate) containing cellular biomass and any cellular debris, which was dried and disposed of in a landfill: the amount of compound 6uo-1,3-BDO recovered is also reported in Table . 2.

table 2

Operating conditions for microfiltration (batch 04 and batch 05) and centrifugation (batch 03)

"party 03" "party 04" "party 05" centrifugation Microfiltration Microfiltration Inlet fermentation broth (kg) 123 138.2 90 Average consumption permeate (kg/m ² /h) 100 ⁽¹⁾ 72.3 107.2 Average permeate temperature (°C) « 40 ^,2) 52.8 57.2 end value VCR - 6.2 9.5 7.6 transmembrane pressure (bar) - 3 3 Bio-1,3-BDO End Balance ⁽³⁾ (%) 98 98 98 Extracted compound bio-1,3- BDO (kg) 6.3 12.4 5.5

⁽¹⁾ Flow rate for feed pump;

⁽²⁾ non-thermostated system;

⁽³⁾ the amount of 6uo-1,3-BDO compound leaving the centrifuge or microfiltration module divided by the amount of bio-1,3BDO compound entering the centrifuge or microfiltration module, x100.

Nanofiltration.

A nanofiltration step was performed to remove water and residual impurities (eg sugars, other organic impurities, salts).

The permeate exiting the microfiltration module originating from batch 04 and batch 05 was fed into the nanofiltration module including the roll-type membrane, while the first aqueous phase (supernatant) leaving the centrifuge originating from batch 03, was fed into a vibratory nanofiltration system referred to as VSEP (Advanced Vibratory Shear Process Unit - New Logic Research Inc.). Both systems were provided with GE DK membranes (Koch Membrane Systems) having a nominal molecular weight cutoff (MWCO) in the range of 150 to 300 daltons.

Additional data regarding the operating conditions under which the nanofiltration was carried out is reported in Table 1. 3. At the end of nanofiltration, a permeate containing 6uo-1,3-BDO, water and residual impurities (for example, salts, acids) was obtained, which was sent for processing using ion-exchange resins, as well as a retentate containing compounds characterized by high steric hindrance ( e.g. proteins, divalent salts) that was dried and disposed of in a landfill: the amount of recovered compound 6uo-1,3-BDO is also reported in Table. 3.

- 10 041653

Table 3

Working Conditions for Nanofiltration (Batch 03, Batch 04 and Batch 05) "Batch 03" "Batch 04"__"Batch 05" __VSEP__ Roll type Roll type

Inlet permeate (kg) - 200 166 Inlet first water phase (kg) 121 - - Initial conductivity (mS/cm) 15 8 eleven end value VCR 6.8 6.2 9.6 Average consumption permeate (kg/h/m ² ) 16 43.3 30.4 average temperature (°C) 49 41 42 End Conductivity (mS/cm) 13 4 4 transmembrane pressure (bar) 30.7 26 25.5 Bio-1,3-BDO End Balance ⁽¹⁾ (%) 96 101 101 Extracted compound bio-1,3- BDO (kg) 5.6 I,4 5.4

⁽¹⁾ The amount of 6uo-1,3-BDO compound leaving the nanofiltration module divided by the amount of 6uo-1,3-BDO compound entering the nanofiltration module x100.

Processing using ion exchange resins.

To remove residual impurities (eg salts, acids) a treatment step was carried out using ion exchange resins.

For this purpose, the permeate exiting the nanofiltration module produced from Lot 03 was divided into two aliquots, referred to as Lot 03-1 and Lot 03-2, prior to being sent to the ion exchange resin treatment step.

The permeate leaving the nanofiltration module, produced from Batch 03 (ie Batch 03-1 and Batch 03-2), Batch 04, and Batch 05, was fed into the ion exchange resin treatment system.

The system was formed from two transparent polyvinyl chloride columns (PVC-U - GF Piping System) having the following dimensions: diameter=151 mm, height=1200 mm. These two columns were connected in series and packed with ion exchange resins: the first column was packed with a strong cationic resin (Dowex™ Monosphere™ 88 - Dow Chemical) while the second column was packed with a weak anionic resin (Dowex™ Monosphere™ 77 - Dow Chemical) .

The purpose of the operation was to obtain a conductivity of the product leaving the second column, <15 µS/cm, and if the exit product had a higher conductivity, said product was fed into said system again after the resin was regenerated.

Said ion exchange resin treatment step was carried out at room temperature (25° C.) while the flow rate was 3.3 OC/h using a metering pump (Delta® 4 solenoid diaphragm metering pump - ProMinent).

Additional data regarding the operating conditions under which the processing step using ion exchange resins was carried out is reported in Table 1. 4. At the end of said treatment, using ion exchange resins, an aqueous solution was obtained containing 6uo-1,3-BDO, water, light organic compounds (for example, ethanol), heavy organic compounds [for example, 4-hydroxy-2-butanone (4-OH- 2B)], unconverted sugars, and any salts not removed that were fed to the rotary evaporator (first evaporation step): the amount of 6uo-1,3-BDO compound recovered is also reported in Table 2. 4.

- 11 041653

Table 4

Operating Conditions for Processing with Ion Exchange Resins (Batch 03-1, Batch 03-2, Batch 04 and Batch 05)

"batch 03-1" "batch 03-2" "party 04" "party 05" Inlet permeate (kg) 61 60 240 162 Layer Volume (l resin/column) 6 12 12 12 Inlet permeate conductivity (mS/cm) 13 13 4 4 Conductivity of the product at the outlet (µS/cm) 1.8 1.6 0.6 I,1 Consumption (OS/h) 3.3 3.3 3.3 3.3 Bio-1,3-BDO End Balance ⁽¹⁾ (%) 100 ⁽²⁾ 98 94 Extracted compound bio-1,3- BDO (kg) 2.9 2.6 AND 2 4.9

⁽¹⁾ The amount of 6uo-1,3-BDO compound leaving the ion exchange resin treatment system divided by the amount of 6uo-1,3-BDO compound entering the ion exchange resin treatment system, x 100;

⁽²⁾ the cumulative amounts obtained from processing batch 03-1 and batch 03-2 using ion exchange resins.

First evaporation.

To remove water and light organic compounds (eg ethanol), the aqueous solutions obtained from the ion exchange resin treatment step were subjected to a first evaporation step.

Thus, the solutions from the ion exchange resin treatment step were fed into a Buchi Rotavapor® having a 20 liter loading bead flask which was heated by immersion in a thermostated water bath. The solution was fed into the loading ball flask in a semi-continuous mode and the vapor phase was removed from the evaporator, obtaining a concentrated solution containing 6uo-1,3-BDO, water, heavy organic compounds [for example, 4-hydroxy-2-butanone (4-OH-2B )], unconverted sugars and any non-removed salts, which was sent to the second evaporation stage, as well as an aqueous phase containing mainly water and trace amounts of ethanol and 6uo-1,3-BDO, which could be sent to recycling to one of the following stages:

(a _1a ) microfiltration;

(a _1b ) centrifugation;

(a ₂ ) nanofiltration;

(b) treatment using ion exchange resins.

Conditions for said first evaporation step were as follows: thermostatic bath temperature: 60°C;

pressure: 70-10 mbar.

Evaporation was considered completed at the end of vapor condensation. Concentrated solutions containing 6uo-1,3-BDO were further purified as described in the examples below. In particular, the concentrated solution originating from Batch 04 was divided into two aliquots, i.e. batch 04-1 and batch 04-2;

concentrated solutions produced from batch 03-2 and batch 04-2 were further purified as described in example 2 (invention) and in example 5 (invention), respectively;

the concentrated solution produced from batch 03-1 was further purified as described in example 3 (comparative);

the concentrated solutions produced from batch 05 and batch 04-1 were further purified as described in example 4 (comparative) and example 6 (comparative), respectively.

Example 2 Purification of 6uo-1,3-BDO (second and third evaporation) (invention).

The second evaporation and third evaporation steps were carried out as reported below under the operating conditions reported in Table 1. 5.

For these purposes, a concentrated solution having its origin in the first evaporation step, i.e. batch 03-2 (approximately 2.6 kg) was fed into a rotary evaporator (Laborota® 4003 control - Heidolph) having a 2 liter loading bead flask.

Heating was carried out by immersing the loading spherical flask in an oil bath equipped with a thermostat. The condenser was formed from a glass coil, in the interior of which water and ethylene glycol (approximately 10%) circulated in a closed circuit.

Cooling of the fluid refrigerant was carried out using an air/liquid cryostat.

The test was started under the operating conditions of the first evaporation stage (ie 60° C. in a thermostated bath and pressure in the range of 70-30 mbar) until confirmation that there was no evaporation from the sample. Any aqueous phase recovered was discarded. Subsequently, the operating conditions used for the stage of the second evaporation and for the stage of the third evaporation, are the corresponding conditions, which are reported in table. 5 (evaporation was considered complete at the end of vapor condensation): second evaporation (stage II) and third evaporation (stage III). The recovered amounts of phase (II) and phase (III) as defined below are also reported in Table 1. 5.

Table 5

Operating conditions and phases extracted from lot 03-2

II-e evaporation and III-e evaporation Phases Weight (g) Pressure (mbar) (Max.) oil bath temperature (°C) Condenser temperature (°C) Evaporation rate (g/h) Phase II 128 12-10 (stage II) PO (stage II) 1 (stage II) 36 (stage II) Phase III 2289 12-10 (stage III) 125 (stage III) 15 (Stage III) 264 (stage III)

From stage II (second evaporation stage), an aqueous phase containing water, organic compounds having a boiling point lower than the corresponding temperature of 6ho-1,3-BDO, and trace amounts of the crude compound 6uo-1,3-BDO was obtained, which was disposed of in a landfill, as well as a concentrated solution (phase II) containing bio1,3-BDO, water and trace amounts of heavy organic compounds [e.g. 4-hydroxy-2butanone (4-OH-2B)], sugars not subjected to conversion, and any non-removed salts that formed the feed stream for the third evaporation stage (stage III).

From stage III (third evaporation stage), an aqueous phase (phase III) containing the purified 6ho-1,3-BDO compound was obtained, as well as an organic phase (phase IV) containing any organic compounds characterized by a boiling point greater than the corresponding temperature for 6ho-1,3-BDO, and trace amounts of crude 6ho-1,3-BDO compound, unconverted sugars, and any salts not removed.

In table. 6 reports a gas chromatographic (GC) analysis performed as described in Example 1 above on the recovered phases and feed stream (batch 03-2).

Table 6

Composition of batch 03-2 and extracted phases "batch 03-2" Phase III Phase II Phase IV Composition ⁽³⁾ (%) H ₂ O 8.8% 1.5% 43.0% n. O. Bio-1,3-BDO 88.0% 96.6% 34.9% 408 g/l Bio-4-OH-2V ⁽¹⁾ 1.0% 0.9% 5.9% And. O. Degradation products of 1,3-BDO ⁽²⁾ 0% 0% 0% n. O. glucose 0.1 g/l 0 g/l 0 g/l 15.5 g/l

⁽¹⁾ Bio-4-hydroxy-2-butanone;

⁽²⁾ a combination of 3-buten-2-one, 2-buten-1-ol (cis- and trans-isomers), 3-buten-1ol, 3-buten-2-ol;

⁽³⁾ the rest up to 100 are other impurities, which are not reported in table. 6.

Phase IV had a burnt sugar appearance and was analyzed using high performance liquid chromatography (HPLC) alone in the operation as described in Example 1 above.

Meanwhile, an Agilent HP6890 gas chromatograph (GC) equipped with a Split/Splitless injector on a Quadrex 007 FFAP column with a length of 25 m, a diameter of 0.32 mm, a 1 μm film was used for the analysis of phase II and phase III, the carrier used was helium at a speed of 50 cm/s, the detector was a flame detector. The determination was carried out using an internal standard with calibration curves for known individual components. In addition, a Karl Fischer titration (831 KF Coulometer Metrohm) was used for phase III water analysis (for phase II, the amount of water was calculated by difference).

Phase III was subsequently fed into the dehydration system for the production of butenols in an operation as described in Example 7, which is reported below.

Example H Purification of 6ho-1,3-BDO (comparative).

The concentrated solution, originating in batch 03-1 and amounting to approximately 2.7 kg, was fed into the distillation column and subjected to batch processing. Distillation was carried out using a 5 liter still and an adiabatic column (diameter=2 cm, height=60 cm) with Sulzer packing. During distillation, residual water and organic compounds having a boiling point in the range between the corresponding temperatures for water and 6uo-1,3-BDO were removed, while high-boiling organic compounds, residual salts and unconverted sugar remained in the distillation cube: the fractions obtained from distillation are reported in Table. 7.

Table 7

Fractions driven away from batch 03-1

Distillation for batch 03-1 Fraction Weight (g) Pressure (mbar) Phlegm number (Max.) vapor temperature (°C) (Max.) Still Temperature (°C) Condenser temperature (°C) Distillation rate (ml/h) 1 93 67 5 36 134 -5 15 2 16 50 5 69 127 -5 3 3 28 50 5 88 127 -5 5 4 14 50 5 116 128 -5 4 5 eleven 50 5 121 128 -5 2 6 13 50 5 124 128 -5 3 7 2159 50 2 125 131 -5 66 8 183 50 2 125 140 -5 73

Fractions enriched in 6uo-1,3-BDO are fraction 7 and fraction 8. However, all recovered fractions were contaminated with a molecule not present in the original solution; the mentioned molecule was identified using various analytical methods (IR-PF, GCMS, GC, NMR) as a ketal, which is formed as a result of the reaction between 6uo-1,3-BDO and 3-buten-2-one (MVK), namely 2,4-dimethyl-2-vinyl-1,3-dioxane (DMV13Diox). In particular, the chromatogram obtained using the gas chromatographic (GC) analysis carried out as described in Example 1 above made it possible to observe the presence in all fractions of a new peak not present in the initial feed stream. The intensity of the peak in different fractions turned out to be different, thus, different analytical methods were used for different fractions. Analysis of NMR in solution, IR-PF and GC-MS identified the mentioned molecule as 2,4dimethyl-2-vinyl-1,3-dioxane (DMV13Diox). Said analyzes were carried out as follows.

Spectroscopic NMR analysis for a sample of fraction 1.

NMR spectra were recorded using a Bruker Avance 400 NMR instrument in deuterated acetone solution. The signal from CH3 of acetone, located in the region of 2.05 ppm. in the ¹ H-NMR spectrum and in the region of 29.5 ppm. in the ¹³ C-NMR spectrum, was taken as a reference signal.

In the ¹ H-NMR spectrum, various products were identified (with different intensities: among them, the compound present in the largest amount is characterized by the presence of a clearly identifiable vinyl group CH ₂ \u003d CH- in the regions of 5.80, 5.32 and 5.29 m. which corresponds in intensity to the set of signals attributed to CH2-O- and CH-O-, characterized by a surprisingly high coupling constant, and this is generally found only for cyclic aliphatic systems). The mentioned results made it possible to identify the ketal particle, in particular, based on the knowledge of the main compounds of the fraction, as DMV13Diox. All interactions, in addition, were evaluated only using the spectrum 1H-1H two-dimensional correlation spectroscopy.

Mass spectrum for sample fraction 7.

Fraction 7 was analyzed using gas chromatography-mass spectrometry (GC-MS) on a spectrometer with a single quadrupole lens (Trace DSQ, Thermo) using the method of analysis of the vapor phase over liquid. The sample was measured in a headspace vial and the sample was heated to 80°C for approximately 1 hour. Subsequently, 1 ml of the liquid gas phase supernatant (surface area and vapor produced from the sample in question) was injected into the gas chromatograph using a method that makes possible separation of air (in excess) from organic components. The analysis conditions used were as follows: gas chromatograph temperature scheme from 50 to 300°C at 4°C/min, split sample injection, injector temperature 280°C, transfer line 250°C. Mass spectra were recorded in the range from 35 to 500 daltons in the electron ionization (EI) mode.

Mass spectrum (EI) for particles at a retention time of 3.9 min.

Despite the invisibility of the molecular ion, as can be assumed, there is a loss of methyl (CH3) from the molecular ion to form ion 127 (relative content 22.5%) and a loss of 27 (allyl) for ion 115 (relative content 80.9%) . Thus, the estimated molecular weight is 142, which would confirm the hypothesis put forward on the basis of the NMR analysis reported above. Based on the structure hypothetically proposed on the basis of NMR analysis, it would also be possible to explain other fragmentary ions obtained in the EI-MS spectrum (indeed, the EI technique generally involves a high degree of fragmentation of organic molecules and thus makes it possible to reconstruct or confirm the structure - 14 041653 tours). In particular:

the main ion 55 (relative content 100%) could correspond to the particle

CH ₂ = CHCHCH ₃ ⁺ *, ion 71 (relative content 35.3%) - particle CH ₂ = CHCH CH ₃ *.

Mass spectrum (EI) for particles at a retention time of 4.44 min.

The main ion 55 (relative content 100%) - particle CH ₂ =CHCHCH ₃ *, ion 71 (relative content 19.3%) - particle CH ₂ =CHSNHOCH ₃ *.

Ion 127 (relative content 32.5%) as a result of the loss of methyl from the molecular ion; loss of 27 (allyl) from the molecular ion for ion 115 (relative content 11.9%).

IR-PF spectrum for sample fraction 1.

IR-PF spectra for the samples deposited on the KBr window were obtained using a Nicolet Nexus FT-IR spectrometer with 64 scans and a resolution of 2 cm' ¹ .

The bands attributed to the vinyl groups of the DMV13Diox product were found in the regions of 3088 cm' ¹ (asymmetric stretching vibration of CH2), 985 and 916 cm' ¹ (fan vibrations of CH and CH2), while bands in the range of 1200-1100 cm' ¹ and in the region of 962 cm' ¹ can be attributed, respectively, to asymmetric and symmetric stretching vibrations of the C-O bond. Similarly, from the DMV13Diox product, vibrations of the C-O-C bond in the region of 1050 cm' ¹ and the C=C double bond in the region of 1640 cm' ¹ could be identified.

In table. 8 reports a gas chromatographic (GC) analysis performed as described in Example 1 on the feed stream (batch 03-1), fraction 7 and fraction 8 produced from the distillation for batch 03-1, and the bottom still obtained at the end of the distillation.

Table 8

GC analysis for fractions enriched in 6ho-1,3-BDO

"batch 03-1" Faction 7 Faction 8 Residue in pot still Composition ⁽³⁾ (%) H ₂ O 3.1% 0.1% 0.1% n. O. Bio-1,3-BDO 88.3% 98.0% 97.5% 544 g/l Bio-4-OH-2V ⁽¹⁾ 1.6% 0% 0% n. O. DMV13Diox ⁽²⁾ 0% 0.4% 0.2% n. O. Glucose And. O. 0 g/l 0 g/l 5.3 g/l

⁽¹ ) Bio-4-hydroxy-2-butanone;

2,4-dimethyl-2-vinyl-1,3-dioxane (expressed as area percentage based on bio-1,3-BDO peak area);

the rest up to 100 are other impurities, which were not reported in the table. 8.

The remainder in the still had a burnt sugar appearance and was analyzed using HPLC alone in the operation as described in Example 1 above. In addition, Karl Fischer titration was used for fraction 7 and fraction 8 for water analysis ( 831 KF Coulometer Metrohm).

Example 4 Purification of 6ho-1,3-BDO (comparative).

The solution originating in Batch 05, which is approximately 4.2 kg, was fed into the distillation column and subjected to batch processing. Distillation was carried out using a 5 liter still and an adiabatic column (diameter=2 cm, height=60 cm) with Sulzer packing. During distillation, residual water and organic compounds having a boiling point in the range between those of water and bio1,3-BDO were removed, while high-boiling organic compounds, residual salts and unconverted sugar remained in the still; fractions obtained from distillation are reported in table. 9.

Table 9

Fractions driven away from lot 05

Distillation for "batch 05" Fraction Weight (g) Pressure (mbar) Phlegm number (Max.) vapor temperature (°C) (Max.) Still Temperature (°C) Condenser temperature (°C) Distillation rate (ml/h) 1 956 35 3 22 95 1 6 2 158 10 5 70 105 1 27 3 142 10 15 74 94 1 9 4 122 10 15 77 95 1 9 5 111 10 15 73 96 1 9 6 3277 12 3 85 107 10 32 7 135 12 3 85 137 10 34

Fractions enriched in bio-1,3-BDO are fraction 6 and fraction 7.

By reducing the pressure in the column and thus the temperature of the system, the formation of 3-buten-2-one (MVK) and the corresponding ketal is avoided. However, in the last distilled fraction (fraction 7), the presence of decomposition products of 6uo-1,3-BDO is noted, which lead to a decrease in the distillation yield: in table. 10 reports a gas chromatographic analysis carried out as described in Example 1 above for fractions enriched in 6uo-1,3-BDO.

Table 10

GC analysis for fractions enriched in 1,3-BDO from Lot 05 "party 05" Faction 5 Faction 6 Faction 7 Residue in pot still Composition ⁽⁴⁾ (%) H ₂ O 4.3% 0.6% 0.3% 0.9% And. O. Bio-1,3-BDO 91.3% 96.5% 98.2% 97.9% 266 g/l Bio-4-OH-2V ⁽¹⁾ 0.6% 0% 0% 0% And. O. DMV13Diox ⁽²⁾ 0% 0% 0% 0% And. O. Degradation products of 1,3-BDO ⁽³⁾ 0% 0% 0.01% 0.58% And. O. Glucose 0.2 g/l 0 g/l 0 g/l 0 g/l 7.6 g/l

⁽¹⁾ Bio-4-hydroxy-2-butanone;

⁽²⁾ 2,4-dimethyl-2-vinyl-1,3-dioxane (expressed as area percentage based on peak area for 6uo-1,3-BDO);

⁽³⁾ a combination of buten-2-one, 2-buten-1-ol (cis- and trans-isomers), 3-buten-1-ol, 3-buten-2-ol;

⁽⁴⁾ the rest up to 100 are other impurities, which are not reported in the table. 10.

The remainder in the still had a burnt sugar appearance and was analyzed using HPLC method alone in the operation as described in Example 1 above. Karl Fischer titration (831 KF Coulometer Metrohm).

Subsequently, cut 6 from batch 5 was fed into the dehydration system for the production of butenols in an operation as described in Example 7 below.

Example 5 Purification of 6uo-1,3-BDO (Second and Third Evaporation) (Invention)

Stages of the second and third evaporation was carried out in accordance with what is reported below, under operating conditions, which are reported in table. eleven.

For this purpose, a concentrated solution originating from the first evaporation step, ie batch 04-2 (approximately 6.8 kg), was fed into a rotary evaporator (Laborota® 4003 control - Heidolph) having a 2 liter loading bead flask.

Heating was carried out by immersing the loading spherical flask in an oil bath equipped with a thermostat. The condenser was formed from a glass coil, in the interior of which water and ethylene glycol (approximately 10%) circulated in a closed circuit. Cooling of the fluid refrigerant was carried out using an air/liquid cryostat.

The test was started under the operating conditions of the first evaporation stage (ie 60° C. in a thermostated bath and pressure in the range of 70-30 mbar) until confirmation that there was no evaporation from the sample. Any aqueous phase recovered was discarded. Subsequently, the operating conditions used for the stage of the second evaporation and for the stage of the third evaporation, are the corresponding conditions, which are reported in table. 11 (evaporation was considered complete at the end of vapor condensation): second evaporation (stage II) and third evaporation (stage III). The recovered amounts of phase (II) and phase (III) as defined below are also reported in Table 1. eleven.

Table 11

Operating conditions and phases extracted from lot 04-2

P-th evaporation and III-th evaporation Phases Weight (g) Pressure (mbar) (Max.) oil bath temperature (°C) Condenser temperature (°C) Evaporation rate (g/h) Phase II 464 12-10 (stage II) 110 (stage II) 1 (stage II) 28 (stage II) Phase III 6827 12-10 (stage III) 125 (stage III) 15 (Stage III) 338 (stage III)

From stage II (second evaporation stage) an aqueous phase containing water, organic compounds having a boiling point lower than the corresponding temperature of 6uo-1,3-BDO, and trace amounts of the crude compound 6uo-1,3-BDO was obtained, which was disposed of in a landfill, as well as a concentrated solution (phase II) containing bio1,3-BDO, water, and trace amounts of heavy organic compounds (e.g., 4-hydroxy-2butanone), unconverted sugars, and any unremoved salts , which formed the feed stream for the stage of the third evaporation (stage III).

- 16 041653

From stage III (third evaporation stage), an aqueous phase (phase III) containing the purified 6ho-1,3-BDO compound was obtained, as well as an organic phase (phase IV) containing any organic compounds characterized by a boiling point greater than the corresponding temperature for 6uo-1,3-BDO, and traces of crude 6uo-1,3-BDO compound, unconverted sugars, and any salts not removed.

In table. 12 reports a gas chromatographic (GC) analysis performed as described in Example 1 above on the recovered phases and feed stream (batch 04-2).

Table 12 Composition of batch 04-2 and recovered phases

"batch 04-2" Phase III Phase II Phase IV Composition ⁽³⁾ (%) H ₂ O 4.2% 0.7% 52.8% And. O. Bio-1,3-BDO 94.1% 97.8% 34.9% 374 g/l Bio-4-OH-2V ⁽¹⁾ 1.1% 0.8% 5.9% N. 0. Degradation products of 1,3-BDO ⁽²⁾ 0% 0% 0% N. 0. Glucose 0.4 g/l 0 g/l 0 g/l 26.9 g/l

⁽¹⁾ Bio-4-hydroxy-2-butanone;

⁽²⁾ a combination of 3-buten-2-one, 2-buten-1-ol (cis- and trans-isomers), 3-buten-1ol, 3-buten-2-ol;

⁽³⁾ the rest up to 100 are other impurities, which are not reported in the table. 12.

Phase IV had a burnt sugar appearance and was analyzed using high performance liquid chromatography (HPLC) alone in the operation as described in Example 1 above.

In addition, a Karl Fischer titration (831 KF Coulometer Metrohm) was used for phase (III) water analysis (for phase II, the amount of water was calculated by difference).

Phase III was subsequently fed into the dehydration system for the production of butenols in an operation as described in Example 7, which is reported below.

Example 6 Purification of 6uo-1,3-BDO (comparative).

The solution, originating in Batch 04-1 and amounting to approximately 4.05 kg, was fed into the distillation column and subjected to batch processing. Distillation was carried out using a 5 liter still and an adiabatic column (diameter=2 cm, height=60 cm) with Sulzer packing. During distillation, residual water and organic compounds with a boiling point in the range between the corresponding temperatures for water and bio 1,3-BDO were removed, while high-boiling organic compounds, residual salts and unconverted sugar remained in the still: o fractions obtained from distillation, reported in table. 13.

Table 13

Factions driven away from batch 04-1

Distillation for "batch 04-1" Fraction Weight (g) Pressure (mbar) Phlegm number (Max.) vapor temperature (°C) (Max.) Still Temperature (°C) Condenser temperature (°C) Distillation rate (ml/h) 1 124 thirty 3 24 97 - 1 16 2 70 12 thirty 82 102 5 6 3 260 12 3 84 103 5 55 4 3446 12 3 86 BY 5 53 5 26 12 3 84 118 10 45

Fractions enriched in 6uo-1,3-BDO are fraction 4 and fraction 5.

By reducing the pressure in the column and thus the temperature of the system, the formation of 3-buten-2-one (MVK) and the corresponding ketal is avoided. However, in the last distilled fraction (fraction 5), the presence of decomposition products of 6uo-1,3-BDO is noted, which lead to a decrease in the yield for distillation: in table. 14 reports a gas chromatographic (GC) analysis performed as described in Example 1 above on bio-1,3BDO enriched fractions and feed (batch 04-1).

- 17 041653

Table 14

GC analysis for fractions enriched in 1,3-BDO from Lot 04-1______

"batch 04-1" Fraction 3 Faction 4 Faction 5 Residue in pot still Composition ⁽⁴⁾ (%) H ₂ O 2.6% 0.4% 0.1% n. O. n. O. Bio-1,3-BDO 95.5% 97.5% 99% 99% 536 g/l Bio-4-OH-2V ⁽¹⁾ 0.9% 0.5% 0% 0% n. O. DMV13Diox ⁽²⁾ 0% 0% 0% 0% n. O. Degradation products 1,3- BDO ⁽³⁾ 0% 0.04% 0% 0.03% n. O. Glucose 0.1 g/l 0 g/l 0 g/l 0 g/l 1.2 g/l

⁽¹⁾ Bio-4-hydroxy-2-butanone;

⁽²⁾ 2,4-dimethyl-2-vinyl-1,3-dioxane (expressed as area percentage based on peak area for 6uo-1,3-BDO);

⁽³⁾ a combination of buten-2-one, 2-buten-1-ol (cis and trans isomers), 3-buten-1-ol, 3-buten-2-ol;

⁽⁴⁾ the rest up to 100 are other impurities, which are not reported in the table. 14.

The remainder in the still had a burnt sugar appearance and was analyzed using HPLC alone in the operation as described in Example 1 above. In addition, Karl Fischer titration was used for water analysis for fractions 3, 4 and 5 ( 831 KF Coulometer Metrohm).

Subsequently, fraction 4 from Batch 04-1 was fed into a dehydration system for the production of butenols in an operation as described in Example 7, which is reported below.

About the Yields of Example 2 (Invention) (Phase III from Lot 03-2), Example 4 (Comparative) (Fraction 6 from Lot 05), Example 5 (Invention) (Phase III from Lot 04-2) and Example 6 (Comparative) ) (fraction 4 from batch 04-1) is reported in Table. 15. No yields are reported for example 3 (comparative) because the fractions enriched in 1,3-BDO are contaminated with 2,4-dimethyl-2-vinyl-1,3-dioxane (DMV13Diox) and are not sent to the system for dehydration for the production of butenols.

Table 15

Yield and recovery rate for fractions from example 1 and example 4 (invention), example 3 and example 5 (comparative)

Total mass balance Total mass balance for bio-1,3- BDO Recovery for fraction enriched in bio-1,3BDO Cumulative extraction rate (g/h) Recovery rate for bio-1,3BDO (g/h) Example 2 (inventions) ("batch 03-2") 100% 99% 97% 139 264 Example 4 (comparative) ("batch 05") 99% 99% 84% 24 32 Example 5 (inventions) ("batch 04-2") 101% 99% 96% 192 338 Example 6 (comparative) ("batch 04-1") 100% 97% 88% 44 53

The cumulative recovery rate was calculated as the sum of the recovered phases or fractions (g) divided by the total test hours (h) as measured from the first condensed drop removed. The recovery rate for Bio-1,3-BOO was calculated as the amount of purified phase or fraction recovered (g) divided by the hours of purification of the individual phase or fraction data (h) as measured from the removed first condensed drop of said phase or fraction.

As can be seen from the data reported in Table. 15, Example 2 and Example 5 (of the invention) appear to show a higher yield (i.e. recovery of a phase or fraction enriched in bio-1,3-BDO) than Example 4 and Example 6 (comparative), and the recovery rate for bio1 ,3-BDO from the used phase or fraction is much larger.

Example 7 Production of bio-butenols from bio-1,3-BDO.

Purified compound 1,3-BDO obtained in example 2 (of the invention) (phase III from lot 03-2) and purified compound bio-1,3-BDO obtained in example 4 (comparative) (fraction 6 from lot 05) , subjected to catalytic dehydration in the operation as follows.

- 18 041653

For these purposes, Catalysts A and B were first synthesized by performing the operation as follows.

Synthesis of catalyst A.

In a glass beaker equipped with a magnetic stir bar, a solution of 870 g of cerium nitrate hexahydrate in 4200 g of water was prepared by vigorous stirring at room temperature (25°C). The resulting solution was transferred to a glass reactor equipped with a plate stirrer and kept under stirring for 15 minutes. 790 g of an aqueous solution at 15% ammonium hydroxide (NH ₄ OH), prepared previously by diluting a commercial aqueous solution at 28-30%, was added to the resulting solution, kept under stirring, using a peristaltic pump, over 3 hours while monitoring the value pH using a Metrohm pH glass electrode (6.0248.030) connected to a Metrohm 691 pH meter. h, at the end of which the pH value was equal to 4.3. Subsequently, another 90 g of the aqueous solution at 15% ammonium hydroxide (NH ₄ OH) prepared before as described above was added to the resulting agitated suspension using a peristaltic pump over a period of 25 minutes to obtain a suspension at pH 9.0. The suspension was left under stirring for 24 h, at the end of which the pH value was measured again, and it turned out to be equal to 8.8, and a precipitate was obtained. The resulting precipitate was filtered off, washed with approximately 10 L of water, and subsequently dried in an oven at 120°C for 2 hours. After drying, the resulting solid was calcined for 6 hours at 600°C.

Synthesis of the catalyst B.

Into a beaker equipped with a Teflon crescent blade stirrer, 200 g of an aqueous solution at approximately 30% ammonium hydroxide (NH ₄ OH) was added and an electrode [Metrohm pH glass electrode (6.0248.030) connected to pH meter Metrohm 780]. In another beaker equipped with a magnetic stir bar, a solution of 200 g of cerium nitrate hexahydrate in 200 g of water was prepared: the cerium nitrate was then solubilized by vigorous stirring at room temperature (25°C). The resulting solution was introduced into a drop dispenser and was added drop by drop over 6 minutes to the aforementioned ammonium hydroxide solution contained in the beaker with constant vigorous stirring. The pH value for the resulting suspension was 10.1. The whole was left under vigorous stirring for 3 hours, during which time 200 ml of water was added and the pH value was measured, which was 9.6. The whole was left under vigorous stirring for another 1.5 h, at the end of which another 200 ml of water was added and the pH value was measured again, which was 9.5. Said suspension was left under vigorous stirring for 64 hours, at the end of which the pH value was measured again, which was 4.5. Subsequently, another 23 g of an aqueous solution at about 30% ammonium hydroxide (NH ₄ OH) was added to give a pH of 9.0: the whole was left under stirring for 6 hours to give a pH of 8.5. Subsequently, 16 g of an aqueous solution at approximately 30% ammonium hydroxide (NH ₄ OH) was added to obtain a pH value of 9.0. The whole was left under vigorous stirring for 17 hours, at the end of which the pH was 7.9, and a precipitate was obtained. The resulting precipitate was filtered off, washed with 2 liters of water and subsequently dried in an oven at 120°C for 2 hours. After drying, the resulting solid was calcined for 5 hours at 600°C.

dehydration reaction.

The dehydration reaction for 6uo-1,3-BDO was carried out in an AISI 316L fixed bed steel tubular continuous reactor having a length of 400 mm and an internal diameter of 9.65 mm. The reactor was thermostated to reaction temperature using an electric heater. For optimal temperature control inside the reactor along its axis there is a pocket having an outer diameter of 3 mm, which accommodates a thermocouple for temperature control.

The catalysts used in these tests were sieved and taken into fractions in the range from 0.5 to 1 mm. A catalyst charge of 3 g was introduced into the reactor between two layers of inert material (corundum), the catalyst layer was held in place by a sintered steel baffle located on the reactor base.

The feed was carried out from the top of the reactor above the area filled with inert material, where this area also functions as an evaporator and allows the reagents to be transferred into a gaseous state and reach the reaction temperature before coming into contact with the catalyst. Thus, the reactor exhibits a downflow arrangement.

Liquid reagents were supplied using a metering pump of the type used in high performance liquid chromatography (HPLC). Gases were supplied using a thermal mass flow meter (TMF). Downstream of the reactor, the resulting products were cooled in a heat exchanger and the condensed liquid was collected in glass vials using a sequence of time controlled valves. Collected

- 19 041653 liquid samples were analyzed using gas chromatographic analysis using an Agilent HP6890 gas chromatograph (GC) equipped with a Split/Splitless injector on a Quadrex 007 column

FFAP with a length of 25 m, a diameter of 0.32 mm, a film of 1 μm, the carrier used was helium at a speed of 50 cm/s, the detector was a flame detector. The determination was carried out using an internal standard with calibration curves for known individual components.

Meanwhile, the non-condensable gases were analyzed using a real-time gas chromatograph (GC) and finally sent to a drum-type gas meter for volume measurement. Real-time gas analysis was performed using an Agilent HP7890 gas chromatograph (GC) having a HP-AI/S column with a length of 50 m, a diameter of 0.53 mm, a 15 micron film, the carrier used was helium at a speed of 30 cm/s , the detector was a flame detector. The determination was carried out using an external standard with calibration curves for known individual components.

Catalytic performance, which is reported in table. 16 and 17 are expressed when calculating the degree of conversion for 6uo-1,3-BDO (C _1j3-BD o) and selectivities to butenols according to the formulas reported below:

{ mo/w^ - (SHISH J _P}11 W,

G ,,-GIi ---------------------------.-----—------- ^x H' ¹ '

...... 1-wU

S, _ —_-----. _х j ” t matu z mU. , where (mol1, _3-N0 ) _in = moles of 1,3-butanediol at the inlet;

(mole1, _3-BPO ) _out .= moles of 1,3-butanediol at the outlet;

moles _{of butenols} = total moles of alkenols [denoting 3-buten-2-ol (methylvinylcarbinol) and 2-buten-1-ol (crotyl alcohol)].

For the case when the totality of the selectivities for all products exceeds 100%, the test result is expressed as the selectivity for butenols, normalized to 100, or

NN!

Prior to starting the catalytic test, the catalyst is subjected to an in situ treatment at 300° C. in a stream of nitrogen (N2). 36 g/h of a 83.3% strength solution of 1,3-butanediol in water are subsequently fed into said reactor at atmospheric pressure (1 bar absolute pressure).

Approximately 3.19 kg of fraction 6 from lot 05, obtained as described in example 4 (comparative), was diluted with 640 g of water. The resulting solution was fed into the dehydration reactor using Catalyst A at 370° C. in the absence of catalyst, showing problems with loss of activity or loss of yield.

Subsequently, in a second test using Catalyst B, 2.135 kg of Phase III from Batch 03-2 prepared as described in Example 2 (Invention) were fed with the addition of 428 g of water. The reaction temperature was set to 355°C. Also in this case, the catalyst did not show problems with loss of activity or loss of yield.

In table. 16 reports the catalytic results obtained for conversion (C%) and selectivity (S%) when calculated as described above.

Table 16

Dehydration Test Results for Purified Compound 6uo-1,3-BDO Obtained in Example 2 (Invention) (Phase III from Lot 03-2) and Example 4 (Comparative) (Fraction 6 from Lot 05)

Catalyst Temperature (°C) Conversion rate (%) Selectivity (%) Exit (%) Example 4 (comparative) (fraction 6 from "batch 05") A 370°C 95 96 91 Example 2 (Inventions) (Phase III of "Lot 032") IN 355°C 98 91 89

Example 8

Purified compound 6uo-1,3-BDO obtained in example 5 (of the invention) (phase III from lot 04-2) and purified compound 6uo-1,3-BDO obtained in example 6 (comparative) (fraction 4 from lot 04-1) was subjected to catalytic dehydration in the operation as follows.

For these purposes, Catalyst C was first synthesized by performing the operation as follows.

Synthesis of catalyst C.

Preparation of a catalyst based on extruded cerium dioxide.

- 20 041653

An extruded catalyst was obtained by performing the operation as described in example 9 of the international patent application WO 2015/173780 in the name of the applicant.

For this purpose, in a glass beaker equipped with a magnetic stir bar, a solution of 870 g of cerium nitrate hexahydrate (99%, from Aldrich, product code 238538; CAS number 10294-41-4) was prepared in 4200 g of water by vigorous stirring at room temperature (25°C). The resulting solution was transferred to a glass reactor equipped with a plate stirrer and kept under stirring for 15 minutes. 790 g of an aqueous solution at 15% ammonium hydroxide (NH ₄ OH) previously prepared by diluting a commercial aqueous solution at 28-30% (from Aldrich, 28-30% NH ₃ Basis ACS reagent; product code 221228; CAS number 1336-21-6) for 3 hours while monitoring the pH value using a Metrohm 6.0248.030 pH glass electrode connected to a Metrohm 691 pH meter. at the end of the addition of the solution, the pH of the suspension was 9.0: the whole was left under stirring for 64 hours, at the end of which the pH turned out to be 4.3. Subsequently, another 90 g of the aqueous solution at 15% ammonium hydroxide (NH ₄ OH) prepared before as described above was added to the resulting agitated suspension using a peristaltic pump over a period of 25 minutes to obtain a suspension at pH 9.0. The suspension was left under stirring for 24 h, at the end of which the pH value was measured again, and it turned out to be equal to 8.8, and a precipitate was obtained. The resulting precipitate was filtered off, washed with approximately 10 L of water, and subsequently dried in an oven at 120°C for 2 hours.

After repeating said preparation for several batches suitable for use when sufficient quantities of material were obtained, the resulting solids were combined and ground in a mortar: 1905 g of the powder thus obtained was subsequently placed in an Erweka planetary mixer having an AMD model motor.

The powder was dry-blended for 1 hour, and subsequently 250 g of an aqueous solution at 25% ammonium hydroxide (NH ₄ OH) previously prepared by diluting a commercial aqueous solution at 28-30% (from Aldrich) was added dropwise in sequence. , 28-30% NH ₃ Basis ACS reagent; product code 221228; CAS number 1336-21-6) for 50 minutes and 250 ml of demineralized water in a similar way for 50 minutes to obtain a paste that was extruded using a Hutt extruder, on which rollers with holes of 2 mm were mounted. The extruded pellets were left to air dry for two days.

Subsequently, a sample of granules weighing 134 g was dried in an oven at 120°C for 2 hours, and subsequently calcined for 6 hours at 600°C to obtain a catalyst based on cerium dioxide. Thereafter, for the catalytic test, the catalyst was prepared by pulverizing it and sieving it to select a fraction in the range of 0.5 to 1 mm.

Catalyst C, prepared as described above, was loaded into the reactor and subjected to pre-treatments as described in Example 7. Tests were started using an 83.3% solution of non-biological 1,3-BDO (Sigma-Aldrich B84784) in demineralized water. at a temperature of 370°C and a flow rate of 36 g/h.

After approximately 125 hours of operation, 4.072 kg of an 83.3% solution of 6uo-1,3-BDO in water, obtained by appropriate dilution of fraction 4 from batch 04-1, obtained as described in example 6 ( comparative). In table. 17 reports the catalytic results obtained for conversion (C%) and selectivity (S%) when calculated as described above. During the test, the performance remained constant and the catalyst showed no problems with loss of activity or loss of yield.

The test was continued using a non-biological stock solution of 1,3-BDO. At this stage, the reaction temperature was set equal to 375°C, which gave in response to a slight loss of conversion. Subsequently, during the same test, 4.226 kg of a solution obtained by diluting with phase III demineralized water from batch 04-2, obtained as described in example 5 (invention), were supplied, so as to obtain 83.3% solution. Also in this case, Table 17 reports the catalytic results obtained for conversion (C%) and selectivity (S%) when calculated as described above. As in the previous case, the performance remained constant and the catalyst showed no problems with loss of activity or loss of yield.

-

Claims (3)

Table 17 Dehydration Test Results for Purified Compound 6uo-1,3-BDO Obtained in Example 6 (Comparative) (Fraction 4 from Lot 04-1) and Example 5 (Invention) (Phase III from Lot 04-2) Catalyst Temperature (°C) Conversion rate (%) Selectivity (%) Exit (%) Example 6 (comparative) (fraction 4 from "batch 04-1") WITH 370°С 94 96 90 Example 5 (Inventions) (Phase III of "batch 04-2") WITH 375°C 95 94 89 Meanwhile, in Table. 18 reports the total yield for butenols, understood to be produced between the yields for the last stage of purification and dehydration. Table 18 Total yield in terms of butenols Average yield for butenols Example 2 (Inventions) (Phase III of "Lot 032") Example 5 (Inventions) (Phase III of "Lot 042") Example 4 (comparative) (fraction 6 from "batch 05") Example 6 (comparative) (fraction 4 from "batch 04-1") mol% mol% Distillation (comparative) - - 84 88 evaporation (three stages) (inventions) 97 96 - - Dehydration with the formation of butenols 89 89 91 90 Average total output 86 85 76 79 As can be seen from the data reported in Table. 18, the method of the present invention for the production of bio-butenols from fermentation broth represents an improvement in terms of average overall yield over the prior art. CLAIM 1. A method for purifying bio-1,3-butanediol from a fermentation broth, comprising the following steps: (a) subjecting the fermentation broth to separation, wherein step (a) includes the following steps: (a _1a ) microfiltration and (a ₂ ) nanofiltration; or (a _1b ) centrifugation and (a ₂ ) nanofiltration; (b) subjecting the permeate product obtained in step (a) to treatment using ion exchange resins; (c) subjecting the product obtained in step (b) to a first evaporation; (d) subjecting the product obtained in step (c) to a second evaporation; (e) subjecting the product obtained in step (d) to a third evaporation to obtain purified bio-1,3-butanediol. 2. A method for purifying bio-1,3-butanediol from a fermentation broth according to claim 1, wherein said microfiltration step (a _1a ) is carried out using membranes having an average pore diameter in the range of 0.01 to 1.0 µm, preferably in the range from 0.02 to 0.08 µm; and/or at a transmembrane pressure in the range of 0.1 to 8 bar, preferably in the range of 1 to 5 bar, said transmembrane pressure being defined as the average pressure between the pressure measured upstream of the microfiltration module and the pressure measured downstream of the microfiltration module; and/or at a temperature in the range from 20 to 90°C, preferably in the range from 40 to 70°C; and/or using ceramic membranes that are immersed, or in a cross current configuration, or in a dynamic cross current configuration, or using planar or hollow fiber polymeric membranes that are immersed or in a cross current configuration. 3. A method for purifying bio-1,3-butanediol from a fermentation broth according to claim 1, wherein said centrifugation step (a _1b ) is carried out at a temperature in the range of 20 to 90°C, preferably in the range of 25 to 70°C, more preferably at room temperature (25°C); and/or -