CN104370692A - Polyol preparation method through glucose hydrogenolysis - Google Patents

Abstract

The invention discloses a method for preparing polyalcohol by hydrogenolysis of glucose, which comprises the following steps: under the action of a catalyst, a high-pressure continuous circulation reactor is used to carry out catalytic hydrogenolysis reaction of glucose to obtain a mixed polyol product. The method of the invention is simple to operate, requires little equipment, is low in cost, has high production efficiency and is beneficial to industrial application.

Description

A kind of method for preparing polyol by hydrogenolysis of glucose

technical field

The invention relates to a method for preparing polyalcohol by hydrogenolysis of glucose.

Background technique

At present, there are many documents and patents on the hydrogenolysis conversion of biomass (such as glucose). Usually, the reaction is multi-step. Glucose is first converted into sugar alcohol and then hydrogenolyzed, which makes the process complicated. For example, Chinese patent 200610068869.5 discloses "a new process for producing ethylene glycol, which includes the preparation of DX value glucose syrup, hydrogenation reaction, refining of sorbitol solution, hydrogenolysis of sorbitol, refining and separation of polyol mixture. "Another example: Chinese patent 200510008652.0 discloses a method for producing C2-4 dihydric alcohols and polyols by aqueous phase cracking of sorbitol. The sorbitol used in this method can be produced by hydrogenation of glucose. In addition, accelerators must be added during some hydrogenolysis reactions, causing corrosion to equipment and high production costs. Moreover, most of the hydrogenolysis conversion reactions using biomass (such as glucose) use noble metal catalysts, which makes the investment in catalysts for this process relatively large. The concentration of biomass raw materials used is low, and the economic benefits are not high. For example: Chinese patent 200480026228.2 discloses "a method for hydrogenolysis of sugar raw material in the presence of a catalyst", which is "wherein the sugar raw material contains one or more polyols, and the catalyst contains: (a) ruthenium or osmium and (b) organophosphines; wherein the hydrogenolysis is carried out in the presence of water and at a temperature greater than 150°C."

Furthermore, the hydrogenolysis conversion of existing biomass (such as glucose) uses batch tanks for hydrogenolysis, which is difficult to carry out continuous operation, and the production efficiency is low. For example, Chinese patent application 200710038143.1 discloses "a method for preparing resin diols from glucitol", which is to catalyze the hydrogenation of glucitol in a batch-type high-pressure reactor.

To sum up, in the prior art, the method for hydrogenolysis of glucose has defects such as many steps, expensive catalyst, or low production efficiency. These defects limit the application and industrialization of glucose hydrogenolysis to prepare low-carbon polyols.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing polyols by hydrogenolysis of glucose, which is simple to operate, requires little equipment, low cost, high production efficiency and is conducive to industrial application.

In order to solve the above-mentioned first technical problem, a method for preparing polyols by hydrogenolysis of glucose of the present invention comprises the following steps:

Under the action of a catalyst, a high-pressure continuous circulation reactor is used to carry out catalytic hydrogenolysis reaction of glucose to obtain mixed polyol products.

The polyol is a C ₂ -C ₆ polyol; the C ₂ -C ₆ polyol includes sorbitol, xylitol, erythritol, mannitol, glycerin, propylene glycol and/or ethylene glycol alcohol. Among them, the selectivity of xylitol and erythritol is much lower than that of propylene glycol and ethylene glycol. The yields of glycerol and butanediol were in between. Among them, propylene glycol has an absolute advantage in the selectivity of 1,2-propanediol. 1,2,4-Butanetriol, 5-Hydroxymethylfurfural and 1,5-Pentanediol are also produced in a small amount, and the molar selectivities are not more than 2%. The raw materials for traditional polyol preparation mostly come from fossil resources such as oil and natural gas. This reaction can not only use industrial glucose as a raw material, but also can use the by-products and even waste materials rich in polyols, aldehydes, and acids in the fermentation industry, such as wine making, etc. Biomass can be effectively used, and economic benefits can be greatly improved. In short, the polyols produced are mainly ethylene glycol, propylene glycol, butanediol, the molar selectivity of sorbitol is less than 20%, and the molar selectivity of 1,2,4-butanetriol, HMF and furfural is less than 5%.

Preferably, the high-pressure continuous flow reactor is a fixed bed reactor or a rotating packed bed reactor.

Preferably, in a fixed-bed reactor, the aqueous glucose solution is continuously passed through a fixed catalyst bed to undergo hydrogenolysis. Preferably, in the fixed bed reactor, the reaction is in the trickle bed mode, and the aqueous glucose solution passes through the catalyst bed through the action of gravity, and the product is also separated from the catalyst bed by gravity; preferably, the solid catalyst is fixed by using quartz wool, etc. ; This method has better continuity and operability than the batch reactor reaction used in traditional biomass hydrogenation.

Preferably, the reaction temperature is 120-280°C, the reaction pressure is 1-100MPa, the hydrogen space velocity is 0.43kg·(h·kgcat) ^-1 , the liquid space velocity of glucose aqueous solution is 0.1-2.4kg·(min·kgcat) ^-1 .

More preferably, the reaction temperature is 150-220°C, the reaction pressure is 1-20MPa, the hydrogen space velocity is 0.43kg·(h·kgcat) ^-1 , the liquid space velocity of glucose aqueous solution is 0.1-1.0kg·(min·kgcat) ^{- 1} .

Most preferably, the reaction temperature is 200-210°C, the reaction pressure is 3-10MPa, the hydrogen space velocity is 0.43kg·(h·kgcat) ^-1 , the liquid space velocity of glucose aqueous solution is 0.1-0.5kg·(min·kgcat) ^{- 1} .

Preferably, in the rotating packed bed reactor, the aqueous glucose solution continuously passes through the rotating catalyst bed to undergo hydrogenolysis reaction. In the rotating bed reaction, since the raw material enters the reactor and rotates into finer droplets, the contact effect with the catalyst bed is increased, and it is separated from the catalyst by centrifugal force, which greatly increases the mass transfer efficiency. During the operation of the high-gravity reactor, the residence time of the reaction is reduced by an order of magnitude, but at the same time the proportion of the gas phase (hydrogen) dissolved in the liquid phase of the reaction is greatly increased, thereby promoting the hydrogenation chain scission reaction; and through By adjusting the level of supergravity, there can be an optimal choice between residence time and mass transfer rate; there are two types of hypergravity reactors: vertical and horizontal.

Preferably, the reaction temperature is 120-280°C, the reaction pressure is 1-100MPa, the supergravity level is 2-300g, the hydrogen space velocity is 0.43kg·(h·kgcat) ^-1 , and the liquid space velocity of glucose aqueous solution is 0.1-2.4kg ·(min·kgcat) ^-1 . In the present invention, when the raw material concentration is low, a higher reaction temperature can be adopted, and the reaction can be carried out above 120°C, and the preferred temperature is between 180°C and 240°C. When the mass concentration of glucose solution is 2%, the reaction temperature can be above 210°C, and under this condition, the types and molar ratios of by-products will decrease, and the proportion of butanediol will increase. At higher glucose concentrations, butanediol is predominantly 1,2-butanediol. At lower glucose concentrations, all three butanediols were produced, and more 1,3-butanediol and 1,2-butanediol were produced. Any suitable reaction pressure can be selected, preferably between 0.5-20 MPa for the present invention.

More preferably, the reaction temperature is 150-220°C, the reaction pressure is 1-20MPa, the supergravity level is 20-250g, the hydrogen space velocity is 0.43kg·(h·kgcat) ^-1 , and the liquid space velocity of glucose aqueous solution is 0.05-2.4 kg (min kgcat) ^-1 .

Most preferably, the reaction temperature is 200-210°C, the reaction pressure is 3-10MPa, the supergravity level is 150-200g, the hydrogen space velocity is 0.43kg·(h·kgcat) ^-1 , and the liquid space velocity of glucose aqueous solution is 0.05-1kg ·(min·kgcat) ^-1 .

Preferably, the aqueous glucose solution uses water as a solvent without adding any acid-base accelerator, and the weight percentage of glucose in the solution is 1-40%, more preferably, the weight percentage of glucose in the solution is 1-20%. This reaction process is a gas-liquid-solid three-phase reaction. The raw material glucose is dissolved in water. Compared with solvents such as dimethyl sulfoxide and valerolactone, it is cost-effective and has high solubility. The mass concentration is selected below 40%, which can avoid the glucose raw material Problems such as coking in the reactor. In addition, without adding any alkaline accelerator, the damage to the equipment is also minimized, and it is not easy to remain in the pipeline. The hydrogen gas and raw glucose solution are continuously fed, and the glucose raw material is sent into the reactor through a liquid-phase high-pressure pump.

Preferably, the catalyst is a 20-40 mesh solid particle.

Preferably, the catalyst includes one or more of Mo, W, Ru, Co, Al, Zr, Ni as the active component of the catalyst, and includes activated carbon, silicon dioxide or aluminum oxide as the carrier.

More preferably, the catalyst includes one or more of Ru, Ni, and Co as active components, and the loading weight ratio of the active components in the catalyst is 0.5%-40%, including one of Mo, W, Al, and Zr. One or several kinds are auxiliary agents, and the loading weight ratio of the auxiliary agents in the catalyst is 5%-40%.

Preferably, the preparation method of the catalyst comprises the steps of:

1) Use the salt solution of the above-mentioned additive metal to impregnate the carrier by isovolumic impregnation, vacuum-dry, dry at 100-150°C and calcined at 300-500°C, and then reduce at 300-500°C;

2) Use the salt solution of the above active component metal to impregnate the carrier by isovolumic impregnation, vacuum-dry, dry at 100-150°C and calcined at 300-500°C, and then reduce at 300-500°C; the reduction temperature is preferably Between 350°C and 500°C, the transition metal will be reduced or partially reduced at this reaction temperature, and a complex of oxide and hydrogen will be formed, which is beneficial to hydrodeoxygenation;

Preferably, in step 1) or 2), if the carrier is activated carbon, the calcination is carried out in nitrogen.

Preferably, in step 1) or 2), if the carrier is silicon dioxide, carbon treatment is performed on the carrier so that it supports metal carbides.

Preferably, in step 1) or 2), the salt is nitrate or ammonium salt

Preferably, if the catalyst does not contain carbon elements, the catalyst is pretreated with a carbon-containing compound during the impregnation process. The pretreated catalyst will increase the product collection rate and the content of ethylene glycol will increase to a certain extent. Among them, Ni element is conducive to the formation of sorbitol, and adding a small amount of noble metal to the catalyst with Ni as the main component cannot effectively change the selectivity of the product. Mo element tends to generate many aldehydes.

The present invention has following beneficial effects:

The method of the invention is simple to operate, requires little equipment, is low in cost, has high production efficiency and is beneficial to industrial application.

Detailed ways

Example 1

Preparation method of Ni/AC catalyst

Nickel nitrate hexahydrate was dissolved in an aqueous solution, and impregnated on the activated carbon carrier using the isovolumic impregnation method according to the mass loading rate of Ni of 10%. The activated carbon carrier was purged in _N2 at 200 °C for two hours in advance. After impregnation, put it into vacuum drying for 1h, then put it into 100°C air drying for 10h, and then calcinate at 400°C in N ₂ atmosphere for 2h.

Example 2

Preparation method of Ni/W/AC catalyst

Before the Ni impregnation in Example 1, W (ammonium metatungstate, Aladdin Company) with a mass loading rate of 15% was impregnated by isovolumetric impregnation. After the impregnation, it was dried in vacuum for 1 hour, and then dried in air at 120°C. 10 h, followed by calcination at 300 °C in _N2 atmosphere for 2 h. Others are the same as embodiment 1.

Example 3

Preparation method of Ni/Al/ _SiO2 catalyst

The silica carrier was calcined in the air at 200°C for 2 hours, and then impregnated with 10% Al ₂ O ₃ on the silica carrier using the isovolumic impregnation method. After the impregnation, put it in vacuum for 1 hour, and then put it in the air at 120°C to dry 10h, and then calcined in air atmosphere at 400°C for 2h. Then impregnate 10% Ni by the isovolumetric impregnation method. After the impregnation, put it into vacuum drying for 1h, then put it into 130°C air drying for 10h, and then calcinate it in the air atmosphere at 500°C for 2h.

Example 4

The Ru-promoted Ni/W/AC catalyst preparation method, on the basis of Example 2, added 0.5% Ru.

Example 5

Ru-promoted Ni/Al/SiO ₂ catalyst preparation method, on the basis of Example 3, add 0.5% Ru.

Example 6

Preparation method of Ru/W/AC catalyst:

According to the amount of W mass loading rate of 15%, the ammonium metatungstate solution was impregnated on the treated activated carbon carrier using the isovolumic impregnation method. After the impregnation, it was placed in vacuum for 1 hour, then placed in air at 120 ° C for 10 hours, and then placed in the air. Calcined in _N2 atmosphere at 400°C for 2h; then impregnated the ruthenium trichloride solution on the activated carbon support using the isovolumic impregnation method according to the Ru mass loading rate of 4%, put it into vacuum drying for 1h after the impregnation, and then put it in 140 °C in air for 10 h, and then calcined at 400 °C in _N2 atmosphere for 2 h.

Example 7

The preparation method of Ru/Al/SiO ₂ catalyst:

The silica carrier was calcined in the air at 200°C for 2 hours, and then impregnated with 10% Al ₂ O ₃ on the silica carrier using the isovolumic impregnation method. After the impregnation, put it into vacuum drying for 1 hour, and then put it in the air at 150°C to dry 10h, and then calcined in air atmosphere at 350°C for 2h. Then 4% Ru was impregnated by isovolumic impregnation. After impregnation, it was dried in vacuum for 1 h, then dried in air at 120 °C for 10 h, and then calcined in air atmosphere at 450 °C for 2 h.

Example 8

Ru/Mo/W/SiO ₂ catalyst preparation method:

The silica carrier was calcined in the air at 200°C for 2h, and then impregnated with 10% W on the silica carrier using the isovolumic impregnation method. After the impregnation, put it into vacuum drying for 1h, and then put it in the air at 120°C for 10h. , and then calcined in an air atmosphere at 400°C for 2h. Then use the isovolumic impregnation method to impregnate the ammonium molybdate solution into the precursor according to the amount of 10%. After the impregnation, put it into vacuum drying for 1h, then put it in the air at 120°C for 10h, and then put it in the air atmosphere at 400°C. Calcination 2h. Then, the silica carrier was impregnated with 1% Ru by mass fraction by isovolumetric impregnation. After impregnation, it was dried in vacuum for 1 h, then dried in air at 120 °C for 10 h, and then calcined in air atmosphere at 400 °C for 2 h.

Example 9

Preparation method of Ru/Mo/SiO ₂ catalyst

The silica carrier was calcined in the air at 200°C for 2 hours, and then the ammonium molybdate solution was impregnated into the precursor at a mass fraction of 10% by isovolumetric impregnation method on the silica carrier, and then put into vacuum drying for 1 hour after impregnation , and then dried in air at 120°C for 10h, and then calcined in air atmosphere at 400°C for 2h. Then, 1% Ru was impregnated on the silica carrier using the isovolumic impregnation method. After the impregnation, it was dried in vacuum for 1 h, then dried in air at 120 °C for 10 h, and then calcined in air atmosphere at 400 °C for 2 h.

Example 10

Preparation method of Ru/Zr/AC catalyst:

According to the amount of zirconium dioxide mass loading rate of 10%, impregnate zirconyl nitrate solution isovolumically on the treated activated carbon carrier. Calcined in _N2 atmosphere for 2h. Then according to the amount of 1% Ru mass loading rate, the ruthenium trichloride solution was impregnated isometrically on the activated carbon support. After the impregnation, it was put into vacuum drying for 1 h, then put into 120 ° C air for 10 h, and then at 400 ° C under N ₂ Calcined in the atmosphere for 2h.

Example 11

Preparation method of Ru/Co/AC catalyst:

Impregnate the cobalt nitrate solution on the treated activated carbon carrier according to the mass loading rate of 10% of cobalt tetroxide. After the impregnation, put it into vacuum drying for 1 hour, then put it into air at 120°C for 10 hours, and then dry it in the air at 400°C. Calcined in _N2 atmosphere for 2h. Then impregnate the ruthenium trichloride solution on the activated carbon carrier according to the amount of 1% Ru mass loading rate by isovolumic impregnation method. After the impregnation, put it into vacuum drying for 1 hour, then put it in the air at 120°C for 10 hours, and then dry it in the air at 400°C. Calcined in _N2 atmosphere for 2h.

Example 12

Carbon pretreated Ru/W/SiO ₂

The silica carrier was calcined in the air at 200°C for 2h, and then impregnated with 10% W on the silica carrier using the isovolumic impregnation method. After the impregnation, put it into vacuum drying for 1h, then put it in the air at 120°C for 10h, and then Calcined in air atmosphere at 400°C for 2h. Then it was pretreated in n-decane at 120°C for 2h, and calcined in air atmosphere at 400°C for 2h. Then use the isovolumetric impregnation method to impregnate 4% Ru by mass fraction. After impregnation, put it into vacuum drying for 1 h, then put it into 120 °C air drying for 10 h, and then calcined in air atmosphere at 400 °C for 2 h.

Example 13

Carbon pretreated Ru/Mo/SiO ₂ ,

In Example 12, W is replaced by Mo, and others are the same as in Example 11.

Example 14

Carbon pretreated Ru/Zr/SiO ₂ ,

W in embodiment 12 is changed into Zr, other is the same as embodiment 11.

Examples 15-16 describe the effect of reaction conditions in different reactors

Example 15

Catalyst evaluation reaction conditions in a fixed bed reactor:

Fixed bed reaction, catalyst 0.5g, reaction pressure 4MPa, WHSV=0.3h ^-1 , H ₂ /C ₆ H ₁₂ O ₆ =64.3:1(molar ratio), 205°C, liquid phase mass concentration 10%, at 500°C The reduction was carried out under pure hydrogen atmosphere for 10 h.

The reaction evaluation is shown in Table 1 below:

Example 16 Catalyst evaluation in a rotating bed reactor Reaction conditions: rotating bed reaction, catalyst 1.0g, reaction pressure 4MPa, WHSV=0.3h ^-1 , H ₂ /C ₆ H ₁₂ O ₆ =64.3:1(molar ratio), At 205°C, the liquid phase concentration is 10%, and the reduction is carried out under pure hydrogen atmosphere at 500°C for 10h. The super gravity level is 2-300g.

Note ⑴: super gravity level 200g

Note ⑵: super gravity level 2g

Note ⑶: super gravity level 300g

Embodiment 17 Low-concentration glucose raw material

Fixed bed reaction, catalyst 1.0g, reaction pressure 4MPa, WHSV=0.03h ^-1 , H ₂ /C ₆ H ₁₂ O ₆ =320:1(molar ratio), 205°C, liquid phase concentration 2%, pure at 500°C The reduction was carried out under a hydrogen atmosphere for 10 h.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. All the implementation manners cannot be exhaustively listed here. All obvious changes or variations derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims (10)

1. glucose hydrogenolysis prepares a method for polyvalent alcohol, it is characterized in that, comprises the steps:

Under catalyst action, adopt high pressure continuous flow to lead to reactor carry out glucose one step catalytic hydrogenolytic cleavage, directly obtain polyol blend product.

2. glucose hydrogenolysis according to claim 1 prepares the method for polyvalent alcohol, it is characterized in that: preferably, and described polyvalent alcohol comprises ethylene glycol, propylene glycol and butyleneglycol; And sorbitol content is lower than 20% in product, the content of hydroxymethylfurfural and furfural is lower than 5%.

3. glucose hydrogenolysis according to claim 1 prepares the method for polyvalent alcohol, it is characterized in that: preferably, and it is fixed-bed reactor or rotating packed-bed reactor that described high pressure continuous flow leads to reactor.

4. glucose hydrogenolysis according to claim 3 prepares the method for polyvalent alcohol, it is characterized in that: preferably, in fixed-bed reactor, by D/W continuously across fixing beds generation hydrogenolysis.

5. glucose hydrogenolysis according to claim 4 prepares the method for polyvalent alcohol, it is characterized in that: preferably, temperature of reaction 120-280 DEG C, and reaction pressure is 1-100MPa, and hydrogen gas space velocity is 0.43kg(hkgcat) ^-1, D/W liquid air speed is 0.1-2.4kg(minkgcat) ^-1;

More preferably, temperature of reaction 150-220 DEG C, reaction pressure is 1-20MPa, and hydrogen gas space velocity is 0.43kg(hkgcat) ^-1, D/W liquid air speed is 0.1-1.0kg(minkgcat) ^-1;

Most preferably, temperature of reaction 200-210 DEG C, reaction pressure is 3-10MPa, and hydrogen gas space velocity is 0.43kg(hkgcat) ^-1, D/W liquid air speed is 0.1-0.5kg(minkgcat) ^-1.

6. glucose hydrogenolysis according to claim 3 prepares the method for polyvalent alcohol, it is characterized in that: preferably, in rotating packed-bed reactor, by D/W continuously across the beds generation hydrogenolysis rotated.

7. glucose hydrogenolysis according to claim 6 prepares the method for polyvalent alcohol, it is characterized in that: preferably, temperature of reaction 120-280 DEG C, and reaction pressure is 1-100MPa, and hypergravity level is 2-300g, and hydrogen gas space velocity is 0.43kg(hkgcat) ^-1, D/W liquid air speed is 0.1-2.4kg(minkgcat) ^-1;

More preferably, temperature of reaction 150-220 DEG C, reaction pressure is 1-20MPa, and hypergravity level is 20-250g, and hydrogen gas space velocity is 0.43kg(hkgcat) ^-1, D/W liquid air speed is 0.05-2.4kg(minkgcat) ^-1;

Most preferably, temperature of reaction 200-210 DEG C, reaction pressure is 3-10MPa, and hypergravity level is 150-200g, and hydrogen gas space velocity is 0.43kg(hkgcat) ^-1, D/W liquid air speed is 0.05-1kg(minkgcat) ^-1.

8. the glucose hydrogenolysis according to claim 4 or 6 prepares the method for polyvalent alcohol, it is characterized in that: preferably, and described D/W is that the water not adding any soda acid promotor makees solvent, and glucose weight percent is in the solution 1-40%; More preferably, glucose weight percent is in the solution 1-20%;

Preferably, described catalyzer is 20-40 object solid particulate;

Preferably, described catalyzer comprise one or more in Mo, W, Ru, Co, Al, Zr, Ni be the activeconstituents of catalyzer; Comprising gac, silicon-dioxide or aluminium sesquioxide is carrier;

More preferably, one or more comprising in Ru, Ni, Co of described catalyzer are activeconstituents, activeconstituents load weight is in the catalyst than being 0.5%-40%, and one or more comprising Mo, W, Al, Zr are auxiliary agent, and auxiliary agent load weight is in the catalyst than being 5%-40%.

9. glucose hydrogenolysis according to claim 8 prepares the method for polyvalent alcohol, it is characterized in that, preferably, the preparation method of described catalyzer, comprises the steps:

1) using the salts solution of above-mentioned promoter metal to use iso volumetric impregnation method to be immersed on carrier, through vacuumizing drying, 100-150 DEG C of drying and 300-500 DEG C of calcining, then reducing at 300-500 DEG C;

2) using the salts solution of above-mentioned activity component metal to use iso volumetric impregnation method to be immersed on carrier, through vacuumizing drying, 100-150 DEG C of drying and 300-500 DEG C of calcining, then reducing at 300-500 DEG C; Reduction temperature is preferably between 350 DEG C-500 DEG C, and under this temperature of reaction, transition metal can be reduced or be partially reduced, and generates the complex compound of oxide compound and hydrogen, and this kind of substance advantageous is in hydrogenation deoxidation.

10. glucose hydrogenolysis according to claim 9 prepares the method for polyvalent alcohol, it is characterized in that:

Preferably, step 1) or 2) in step, if carrier is gac, then calcines and carry out in nitrogen;

Preferably, step 1) or 2) in step, if when carrier is silicon-dioxide, carbon process is carried out to carrier and makes its loaded metal carbide;

Preferably, step 1) or 2) in, described salt is nitrate or ammonium salt;

Preferably, if not containing carbon in catalyzer, then use carbon compound to carry out pre-treatment to catalyzer in steeping process.