CN104529727B - A kind of technique of methanol-to-olefins coproduction low-carbon (LC) mixed aldehyde - Google Patents

Abstract

The invention provides a process for co-producing low-carbon mixed aldehydes from methanol to olefins. The process comprises the following steps: Step 1: contact reaction between methanol and SAPO-34 molecular sieve; Step 2: dehydrate the reaction product of Step 1 and perform gas separation to obtain tail gas and liquefied petroleum gas products containing ethylene and propylene; Three: Mix the tail gas containing ethylene and propylene with the mixed gas of _H2 and CO, and then contact with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde. The technical solution provided by the present invention has the following positive effects: (1) For the first time, the process of co-producing low-carbon mixed aldehydes from methanol to olefins and the transformation of the catalytic cracking unit into a process of methanol-to-olefins and subsequent generation of low-carbon mixed aldehydes are proposed, and the methanol reaction product tail gas There is no need to separate ethylene and propylene, only hydrocarbons above C ₄ need to be separated, which greatly reduces the energy consumption of separation.

Description

A process for the co-production of low-carbon mixed aldehydes from methanol to olefins

technical field

The invention relates to a process for co-producing low-carbon mixed aldehydes from methanol to olefins, which belongs to the field of fine petrochemical industry.

Background technique

At present, China's oil refining capacity is seriously overcapacitated, some refineries have overcapacity, equipment utilization rate is low, and coal chemical industry production is rapid, with methanol system energy chemical industry as the main pattern, methanol to olefins shows good economic benefits, so traditional catalytic cracking units are used There are good business opportunities for reforming methanol to olefins.

The methanol-to-olefins (MTO) reaction was first discovered in the early 1970s using the ZSM-5 catalyst, but it has a short lifetime. Later, UOP and Norsk Hydro developed MTO technology based on SAPO-34 molecular sieve catalyst, which can selectively produce ethylene and propylene.

The methanol-to-olefins unit includes the reaction-regeneration part and the olefin separation part of the reaction gas. The reaction technology has become increasingly mature, but insufficient attention has been paid to the development of the separation technology. Since the energy consumption of the olefin separation part accounts for 2/3 of the entire device, the use of conventional separation technology to separate ethylene and propylene and then high-value utilization of it will greatly reduce its economical efficiency. CN102040442A discloses a comprehensive method for separating the MTO reaction gas, which cools the MTO reaction gas to the dew point and sends it to the water-gas separation tower to effectively remove the silicon-aluminum molecular sieve catalyst powder and acidic oxygen-containing organic compounds in the MTO reaction gas. At the same time, most of the organic matter and by-product water in the MTO reaction product are recovered for further treatment and reuse. According to this method, the content of ethylene and propylene in olefin gas can reach more than 70%, but its operation process is complicated, and whether it is economically feasible remains to be discussed. The technical case disclosed in CN101921161A adopts C3 as detergent and does not use ethylene refrigerant. Although it has the advantages of simple process flow, low operating cost, and less ethylene loss, the process is only suitable for ethylene separation, and it is not suitable for the separation of methanol to olefins. The above components of product C4 should not be applicable. CN102503757A provides a low-carbon hydrocarbon separation and methanol-to-olefins (M-OS/MTO) gas separation process, the method includes adding an absorbent separation tower before the demethanizer, and separating a stream from the tower as The main absorbent of the demethanizer absorbs C2 and C3. At present, only the Shenhua Baotou MTO plant has been industrialized in China. This process uses propane-based absorbents to enter the top plate of the demethanizer to absorb components of C2 and above. The absorption efficiency is good, but there are absorbents There are many disadvantages such as large dosage, long cycle route, high investment and high energy consumption.

WO2013144735A1 discloses a method for producing butanol by hydroformylation _{of C2} and C3 mixed olefins. In order to avoid the high energy consumption caused by the separation of ethylene and propylene, mixed olefins are hydroformylated to produce mixed alcohols (C3 and C4 alcohols), and then propanol is dehydrogenated to produce propylene, which is then recycled to the hydroformylation stage to continue production butanol. The technical solution disclosed in CN101768062A is a method for producing propionaldehyde and butyraldehyde by using a water-soluble rhodium-phosphine complex catalyst to carry out a hydroformylation reaction with a mixed gas rich in ethylene and propylene after concentrated catalytic dry gas. However, the water-soluble rhodium/phosphine complex aims to make the product and the catalyst easy to separate and simplify the process flow, but due to the low mass transfer efficiency of the two-phase reaction, the addition of a phase transfer agent will cause separation problems and may even cause emulsification and increase the difficulty of phase separation. The activity and selectivity of the oil-soluble rhodium/phosphine complex catalyst are relatively high, the research on the reaction mechanism and kinetics is easy to in-depth, the reaction conditions are mild, easy to control, and there are few side reactions. It is suitable for industrial applications in olefin hydroformylation and related occupy a dominant position in academic research.

Contents of the invention

In order to solve the above-mentioned technical problems, the object of the present invention is to provide a process for co-producing low-carbon mixed aldehydes from methanol to olefins, using methanol as a raw material to prepare low-carbon olefins, and simultaneously hydroformylation to prepare propionaldehyde and butyraldehyde. Avoiding the high energy consumption caused by the traditional cryogenic separation of ethylene and propylene can also realize the high-value utilization of olefins and promote the transformation and development of the olefins industry to fine chemicals.

In order to achieve the above object, the invention provides a process for the co-production of low-carbon mixed aldehydes from methanol to olefins, which comprises the following steps:

Step 1: making methanol contact with SAPO-34 molecular sieves;

Step 2: Dehydrating the reaction product of Step 1 (preferably dehydrating to a water content lower than 20ppm) and performing gas separation to obtain tail gas and liquefied petroleum gas products containing ethylene and propylene;

Step 3: Mix the tail gas containing ethylene and propylene with the mixed gas of _H2 and CO, and then contact with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde.

In the above process provided by the present invention, preferably, the reaction conditions in step 1 are: reaction temperature 350-550°C, pressure 0.05-0.3MPa, space velocity 2.0-6.0h ^-1 , water-alcohol ratio 0.1-0.3: 1.

In the above process provided by the present invention, preferably, the reaction conditions in step 3 are: the reaction temperature is 70-120°C, the pressure is 1.0-3.0MPa, and the catalyst concentration in terms of rhodium atoms is 100-300ppm; more preferably , In the gas mixed with the tail gas containing ethylene and propylene and the mixed gas of _H2 and CO, the volume ratio of _H2 to CO is 0.5-2.0:1, and the volume ratio of olefins to syngas is less than or equal to 1:1.

In the above process provided by the present invention, the methanol-to-olefins reaction in step 1 can be carried out in a methanol-to-olefins reactor, which is a fluidized bed reactor, and SAPO-34 is used as a methanol-to-olefins catalyst, and its average pore size is preferably 0.2-0.6nm, preferably 0.4nm.

In the technique provided by the present invention, the hydroformylation reaction in step 3 can be carried out in the synthesis aldehyde reactor, preferably, the hydroformylation catalyst adopted is a catalytic system composed of a rhodium complex and a phosphine ligand , or a rhodium complex catalyst (SPION-Rh) supported by magnetic nano-Fe ₃ O ₄ particles. In addition to the rhodium-phosphine complex, the above catalyst system needs to add an excess of separate phosphine ligands, and the molar ratio of the additional phosphine ligands to the rhodium-phosphine complex is 100-600:1. A mixture of the two is referred to herein as a catalytic system. The rhodium complex supported by the magnetic nanometer Fe ₃ O ₄ particles does not need additional phosphine ligands when used.

According to a specific embodiment of the present invention, preferably, the aforementioned rhodium complex is one of compounds having the following structures: Rh(acac)(CO) ₂ , [Rh(CO) ₂ Cl] ₂ , trans-RhCl( CO)(PPh ₃ ) ₂ , RhH(CO)(PPh ₃ ) ₃ , Rh(CO)(PPh ₃ )(acac); where acac represents acetylacetone and PPh ₃ represents triphenylphosphine; individual phosphine ligands including triphenylphosphine and/or triphenylphosphite;

More preferably, the phosphine-rhodium ratio (P/Rh) in the catalytic system composed of the rhodium complex and the phosphine ligand is 100-600:1.

_The catalyzer of the rhodium complex compound that the magnetic nanometer _Fe3O4 particle that the present invention adopts can be with bridging ligand bonded to the superparamagnetic Fe coated with silicon dioxide that exposes amino groups on the surface The surface of ₃ O ₄ nanoparticles (SPION) is obtained; wherein, the bridging ligand adopted has the following structure:

R is a carboxyl group at a different substituent position.

Above-mentioned magnetic nanometer Fe ₃ O ₄ the catalyst of the rhodium complex compound that particles are carried can be prepared through the following steps:

Disperse 20 mg of superparamagnetic Fe ₃ O ₄ nanoparticles coated with silica shells with amino groups exposed on the surface in 10 mL of DMF to obtain solution A;

Prepare a DMF solution of EDC/HOBt with a concentration of 0.4-0.8M, add diphenylphosphine-3-benzoic acid and tetraethylammonium chloride in sequence to obtain solution B, and the molar ratio is: diphenylphosphine-3 - Benzoic acid: EDC/HOBt=1:1.1-1.5, EDC/HOBt: tetraethylammonium chloride=1:1;

Add solution B to solution A, react at room temperature (preferably 20-24 hours);

After the reaction is completed, suck out the product with a magnet, disperse it in toluene, add the toluene solution of the rhodium complex under nitrogen protection and stirring, react for 1-5 hours, suck out the product with a magnet, and wash to obtain magnetic nano Fe ₃ O ₄ Catalysts of rhodium complexes supported on particles;

Wherein, when solution B is added to solution A, 1 mg of superparamagnetic Fe ₃ O ₄ nanoparticles coated with silicon dioxide or 4-aminophthalic acid coated superparamagnetic Fe ₃ O ₄ nanoparticles with exposed amino groups on the surface Corresponding to 2-10 μmol of diphenylphosphine-3-benzoic acid; when rhodium complex is added, 1 mg of silica-coated superparamagnetic Fe ₃ O ₄ nanoparticles with exposed amino groups on the surface or 4-aminophthalic acid-coated The superparamagnetic Fe ₃ O ₄ nanoparticles of the layer correspond to 0.8-2 μmol rhodium complex; preferably, the amount of solution A: the amount of solution B: the amount of rhodium complex solution = 20 mg: 0.2-1 mmol: 16-40 μmol, wherein, the addition amount of solution A is based on the mass of superparamagnetic Fe ₃ O ₄ nanoparticles coated with silicon dioxide with amino groups exposed on the surface or by superparamagnetic Fe 3 O 4 nanoparticles coated with 4-aminophthalic acid. _Fe3O4The mass meter _of the superparamagnetic _Fe3O4 nanoparticle adopted by the nanoparticle, the add _- on of solution B is based on the molar weight of diphenylphosphine-3-benzoic acid, the add-on of rhodium complex solution In terms of moles of rhodium complexes.

According to a specific embodiment of the present invention, the silica _- coated superparamagnetic _Fe3O4 nanoparticles whose surface exposes amino groups can be prepared by the following steps:

Mix 2-4mmol Fe(CO) ₅ , oleic acid with 20-25mL trioctylamine (TOA), and the amount of oleic acid added is 1.1 times the molar amount of Fe(CO) ₅ ; the reaction can be carried out in a 100mL three-necked flask conduct;

Heated to 280°C under the protection of argon atmosphere, and reacted for 2 hours to obtain a black solution;

After removing impurities, superparamagnetic _Fe3O4 nanoparticles are obtained _;

After concentrating the chloroform solution of superparamagnetic Fe ₃ O ₄ nanoparticles with a concentration of 0.05 mg/mL under reduced pressure, add a 15 mM sodium dodecylsulfonate aqueous solution and ultrasonically disperse, superparamagnetic Fe ₃ O ₄ nano The concentration of particles is 0.05-0.1mg/mL;

Put the above solution on a shaker, add n-octyltrimethoxysilane (OCTMO) ₉ times the mass of superparamagnetic _Fe3O4 nanoparticles, shake well, continue to add dropwise with n-octyltrimethoxysilane, etc. volume of 3-aminopropyltriethoxysilane (APS), continue to react for 48h;

After the reaction, the mixed solution after the reaction is placed on a magnet, and the solution is discarded after standing for 8-12 hours, and the precipitate is collected and washed with water to obtain superparamagnetic Fe ₃ O ₄ nanoparticles coated with silicon dioxide with amino groups exposed on the surface.

According to specific embodiments of the present invention, preferably, the preparation method of SPION-Rh nanometer catalyst comprises the following specific steps:

(1) Preparation of silica-coated superparamagnetic nanoparticles with exposed amino groups on the surface

Mix 2-4mmol Fe(CO) ₅ , oleic acid and 20-25mL trioctylamine into a three-necked flask with a volume of 100mL, and the amount of oleic acid added is 1.1 times the molar amount of Fe(CO) ₅ ; The three-necked flask was fed with argon, heated to 280° C. under the protection of argon atmosphere, and reacted for 2 hours to obtain a black solution; after removing impurities, superparamagnetic Fe ₃ O ₄ nanoparticles were obtained.

i. configuration 100mL concentration is 0.05mg/mL superparamagnetic Fe ₃ O chloroform solution _A of nanoparticles;

ii. Place the chloroform solution A at 40°C, and concentrate the solution to 10 μL by distillation under reduced pressure at a speed of 150 rpm;

iii. Add 100 mL of 15 mM sodium dodecylsulfonate aqueous solution to the concentrated chloroform solution A, and sonicate in a 40°C water bath with an ultrasonic power of 60 W for 10 minutes to obtain a mixed solution B;

iv. Put the mixed solution B on a shaker, add 50 μL n-octyltrimethoxysilane, shake well for 30 minutes; continue to drop 50 μL 3-aminopropyltriethoxysilane, and continue the reaction for 48 hours;

After the reaction, the solution in step iv was placed on a magnet, and the solution was discarded after standing for 10 h, and the precipitate was collected and washed three times with water to obtain superparamagnetic Fe ₃ O ₄ nanoparticles coated with silica.

(2) Preparation of SPION-Rh nanocatalyst

i. the superparamagnetic Fe ₃ O ₄ nanoparticle of 20mg silica coating is dispersed in 10mL DMF, obtains solution A;

ii. Disperse 0.2mmol of diphenylphosphine-2-benzoic acid in 0.5mL of EDC/HOBt DMF solution with a concentration of 0.6mmol/mL, and add 0.3mmol of tetraethylammonium chloride (TEA) to activate for 10min to obtain Solution B, wherein EDC is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, HOBt is 1-hydroxybenzotriazole monohydrate, and DMF is dimethylformamide;

iii. Add solution B to solution A, place on a shaker, and react at room temperature for 24 hours;

iv. After the reaction is completed, suck out the product with a magnet, disperse it in toluene, add 10 mL of toluene solution containing 20 μmol rhodium complex under nitrogen protection and stirring, and react for 1-5 hours , the product was sucked out with a magnet, and washed three times with toluene to obtain the SPION-Rh catalyst.

The present invention also provides a method for transforming a catalytic cracking unit for the process of co-producing low-carbon mixed aldehydes from methanol to olefins, which includes the following steps:

Replace catalytic cracking raw material with methanol, replace catalytic cracking catalyst with SAPO-34 molecular sieve;

Methanol enters the catalytic cracking unit and reacts with SAPO-34 molecular sieve, and then the reaction product is dehydrated and then enters the gas separation unit of the catalytic cracking unit for gas separation to produce tail gas containing ethylene and propylene and liquefied petroleum gas products;

The tail gas containing ethylene and propylene is mixed with the mixed gas of _H2 and CO, and then enters the hydroformylation reactor to contact with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde.

The method replaces petroleum with methanol to produce low-carbon olefin products, which effectively alleviates the shortage of domestic petroleum resources, and promotes the rapid transformation and development of the low-carbon olefin industry with the energy and chemical industry of the methanol system as the main structure; at the same time, mixed hydroformylation is carried out to prepare propionaldehyde And butyraldehyde can not only avoid the high energy consumption caused by the traditional cryogenic separation of ethylene and propylene, but also realize the high-value utilization of olefins, and promote the transformation and development of the olefins industry to fine chemicals.

In the process of the present invention, the reaction product of methanol enters the original gas separation device after the dehydration treatment of the catalytic cracking unit to produce tail gas containing ethylene and propylene and heavy components such as liquefied petroleum gas. Propionaldehyde and butyraldehyde are produced by hydroformylation of synthesis gas, and propanol and butanol are produced by hydrogenation. Compared with the traditional hydroformylation of ethylene and propylene to produce propanol and butanol respectively, the process is short, investment is low, energy consumption is low, Economic benefits are more competitive.

The technical solution provided by the present invention has the following positive effects:

(1) For the first time, the process of co-producing low-carbon mixed aldehydes from methanol to olefins and the transformation of the catalytic cracking unit into a process of methanol-to-olefins followed by low-carbon mixed aldehydes were proposed. The tail gas of methanol reaction products does not need to separate ethylene and propylene, but only needs to separate C ₄ The above hydrocarbons greatly reduce the energy consumption of separation.

(2) The magnetic nanoparticle-rhodium (SPION-Rh) catalyst used in the synthesis of aldehyde, due to the huge surface area of the nanoparticle, can be combined with rhodium to construct a nanocatalytic cluster (cluster), which is beneficial to improve its catalytic efficiency.

(3) The introduction of magnetic particles makes it possible to easily recover metal rhodium by means of an external magnetic field, and easily solve the problem of difficult recovery of rhodium in industrial homogeneous catalysis.

Description of drawings

Fig. 1 is a schematic flow diagram of the conversion of the catalytic cracking unit into methanol-to-olefins co-production of low-carbon mixed aldehydes in the embodiment.

detailed description

In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

All the processes used in the examples are converted from catalytic cracking unit to co-production of low-carbon mixed aldehydes from methanol to olefins, the flow chart of which is shown in Figure 1. The methanol raw material first enters the MTO reactor. After the reaction, the components above C ₄ are separated and removed by dehydration, and then the mixed hydrocarbons of C ₂ and C ₃ enter the synthesis aldehyde reactor to contact with the hydroformylation catalyst to produce propionaldehyde and butyraldehyde. The MTO reactor is connected in series with the synthesis aldehyde reactor.

Example 1

This embodiment provides a process for the co-production of low-carbon mixed aldehydes from methanol to olefins, which includes the following steps:

Methanol enters the methanol-to-olefins reactor and reacts with SAPO-34 molecular sieve (average pore size about 0.4nm). The reaction product enters the separator after dehydration to remove C ₄ and above hydrocarbons, and the remaining low-carbon olefin gas and synthesis gas ( The volume ratio is 1:3, and the H ₂ /CO volume ratio in the synthesis gas is 1:1) are mixed together into the synthesis aldehyde reactor and contacted with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde.

Among them, the reaction temperature of the methanol-to-olefins reactor is 450°C, the pressure is 0.2MPa, the reaction space velocity is 4.0h ^-1 , the water-alcohol ratio is 0.2, and the composition of the dehydrated gas at the reactor outlet is shown in Table 1.

Synthetic aldehyde reactor reaction temperature is 100 ℃, pressure is 2.5MPa, catalytic system is the mixture of Rh(acac)(CO) ₂ and triphenylphosphine, phosphine-rhodium ratio is 400, catalyst concentration (as rhodium atom) 200ppm.

The results of the hydroformylation reaction are shown in Table 2.

Example 2

This embodiment provides a process for the co-production of low-carbon mixed aldehydes from methanol to olefins, which includes the following steps:

Methanol enters the methanol-to-olefins reactor and reacts with SAPO-34 molecular sieve (average pore size about 0.4nm). The reaction product enters the separator after dehydration to remove C ₄ and above hydrocarbons, and the remaining low-carbon olefin gas and synthesis gas ( The volume ratio is 1:3, and the volume ratio of H ₂ /CO in the synthesis gas is 1.5:1) are mixed together into the synthesis aldehyde reactor and contacted with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde.

Among them, the reaction temperature of the methanol-to-olefins reactor is 480°C, the pressure is 0.18MPa, the reaction space velocity is 4.5h ^-1 , the water-alcohol ratio is 0.3, and the composition of the dehydrated gas at the reactor outlet is shown in Table 1.

Synthetic aldehyde reactor reaction temperature is 110 ℃, and pressure is 2.0MPa, and catalytic system is the mixture of Rh(CO)(PPh ₃ )(acac) and triphenylphosphine, and phosphine-rhodium ratio is 500, and catalyst concentration (calculated by rhodium atom) )215ppm.

The results of the hydroformylation reaction are shown in Table 2.

Example 3

This embodiment provides a process for the co-production of low-carbon mixed aldehydes from methanol to olefins, which includes the following steps:

Methanol enters the methanol-to-olefins reactor and reacts with SAPO-34 molecular sieve (average pore size about 0.4nm). The reaction product enters the separator after dehydration to remove C ₄ and above hydrocarbons, and the remaining low-carbon olefin gas and synthesis gas ( The volume ratio is 1:3, and the volume ratio of H ₂ /CO in the synthesis gas is 0.8:1) are mixed together into the synthesis aldehyde reactor and contacted with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde.

Among them, the reaction temperature of the methanol-to-olefins reactor is 500°C, the pressure is 0.22MPa, the reaction space velocity is 5.0h ^-1 , the water-alcohol ratio is 0.25, and the composition of the dehydrated gas at the reactor outlet is shown in Table 1.

Synthetic aldehyde reactor reaction temperature is 80 ℃, pressure is 1.5MPa, catalytic system is the mixture of RhH(CO)(PPh ₃ ) ₃ and triphenyl phosphite, phosphine-rhodium ratio is 450, catalyst concentration (calculated as rhodium atom) 180ppm.

The results of the hydroformylation reaction are shown in Table 2.

Example 4

This embodiment provides a process for the co-production of low-carbon mixed aldehydes from methanol to olefins, which includes the following steps:

Methanol enters the methanol-to-olefins reactor and reacts with SAPO-34 molecular sieve (average pore size about 0.4nm). The reaction product enters the separator after dehydration to remove C ₄ and above hydrocarbons, and the remaining low-carbon olefin gas and synthesis gas ( The volume ratio is 1:2, and the volume ratio of H ₂ /CO in the synthesis gas is 1.2:1) are mixed together into the synthesis aldehyde reactor and contacted with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde.

Among them, the reaction temperature of the methanol-to-olefins reactor is 450°C, the pressure is 0.3MPa, the reaction space velocity is 4.0h ^-1 , the water-alcohol ratio is 0.2, and the composition of the dehydrated gas at the reactor outlet is shown in Table 1.

Synthetic aldehyde reactor reaction temperature is 95°C, pressure is 2.0MPa, the catalytic system is a mixture of Rh(CO)(PPh ₃ )(acac), triphenylphosphine and triphenylphosphite, the ratio of phosphine to rhodium is 600, and the triphenylphosphine ratio is 600. The molar ratio of phenylphosphine and triphenyl phosphite is 1:1, and the catalyst concentration (calculated as rhodium atoms) is 220ppm.

The results of the hydroformylation reaction are shown in Table 2.

Example 5

This embodiment provides a process for the co-production of low-carbon mixed aldehydes from methanol to olefins, which includes the following steps:

Methanol enters the methanol-to-olefins reactor and reacts with SAPO-34 molecular sieve (average pore size about 0.4nm). The reaction product enters the separator after dehydration to remove C ₄ and above hydrocarbons, and the remaining low-carbon olefin gas and synthesis gas ( The volume ratio is 1:2, and the H ₂ /CO volume ratio in the synthesis gas is 1:1) are mixed together into the synthesis aldehyde reactor and contacted with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde.

Among them, the reaction temperature of the methanol-to-olefins reactor is 400°C, the pressure is 0.25MPa, the reaction space velocity is 4.0h ^-1 , the water-alcohol ratio is 0.2, and the composition of the dehydrated gas at the outlet of the reactor is shown in Table 1.

Synthetic aldehyde reactor reaction temperature is 100 ℃, pressure is 2.5MPa, catalytic system is the mixture of RhCl(CO)(PPh ₃ ) ₂ and triphenyl phosphite, phosphine-rhodium ratio is 300, catalyst concentration (as rhodium atom) 180ppm.

The results of the hydroformylation reaction are shown in Table 2.

Example 6

This embodiment provides a process for the co-production of low-carbon mixed aldehydes from methanol to olefins, which includes the following steps:

Methanol enters the methanol-to-olefins reactor and reacts with SAPO-34 molecular sieve (average pore size about 0.4nm). The reaction product enters the separator after dehydration to remove C ₄ and above hydrocarbons, and the remaining low-carbon olefin gas and synthesis gas ( The volume ratio is 1:2, and the H ₂ /CO volume ratio in the synthesis gas is 1:1) are mixed together into the synthesis aldehyde reactor and contacted with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde.

Among them, the reaction temperature of the methanol-to-olefins reactor is 380°C, the pressure is 0.2MPa, the reaction space velocity is 3.0h ^-1 , the water-alcohol ratio is 0.2, and the composition of the dehydrated gas at the outlet of the reactor is shown in Table 1.

Hydroformylation catalyst is SPION-Rh catalyst, and its preparation process is as follows:

(1) Preparation of silica-coated superparamagnetic nanoparticles with exposed amino groups on the surface:

Place 0.4mL Fe(CO) ₅ (3mmol), 1mL (3.3mmol) oleic acid and 20mL TOA in a three-neck flask with a volume of 100mL; heat to 280°C under the protection of Ar, react for 2 hours to obtain a black solution, and remove impurities After that, Fe ₃ O ₄ magnetic nanoparticles were obtained.

i. configuration 100mL concentration is 0.05mg/mL superparamagnetic Fe ₃ O chloroform solution _A of nanoparticles;

ii. Place solution A at 40°C, and concentrate the solution to 10 microliters by distillation under reduced pressure at a speed of 150 rpm;

iii. Add 100mL of sodium dodecylsulfonate aqueous solution with a concentration of 15mM to the concentrated solution A, and sonicate in a 40°C water bath with an ultrasonic power of 60W for 10min to obtain solution B;

iv. Put solution B on a shaker, add 50 μL n-octyltrimethoxysilane, shake well for 30 minutes, then continue to drop 50 μL 3-aminopropyltriethoxysilane, and continue the reaction for 48 hours;

After the reaction, place the solution obtained in step iv on a magnet, discard the solution after standing for 10 h, collect the precipitate and wash it with water three times to obtain superparamagnetic Fe ₃ O ₄ nanoparticles coated with silica.

(2) Using Rh(acac)(CO) ₂ as the active catalyst precursor to prepare SPION-Rh nanocatalyst:

i. 20 mg of silica-coated superparamagnetic Fe ₃ O ₄ nanoparticles were dispersed in 10 mL of DMF to obtain solution A;

ii. Disperse 0.2 mmol of diphenylphosphine-2-benzoic acid in 0.5 mL of EDC/HOBt in DMF with a concentration of 0.6 mmol/mL, and add 0.3 mmol of TEA to activate for 10 minutes to obtain solution B;

iii. Add solution B to solution A, place on a shaker, and react at room temperature for 24 hours;

iv. After the reaction is completed, use a magnet to suck the product out, disperse it in toluene, add 10 mL of toluene solution containing 20 μmol Rh(acac)(CO) under nitrogen protection and stirring, react for ₂ hours, use a magnet to suck the product out, and use Washed three times with toluene to obtain SPION-Rh catalyst.

The reaction temperature of the synthesis aldehyde reactor is 90°C and the pressure is 2.0MPa.

The results of the hydroformylation reaction are shown in Table 2.

Example 7

This embodiment provides a process for the co-production of low-carbon mixed aldehydes from methanol to olefins, which includes the following steps:

Methanol enters the methanol-to-olefins reactor and reacts with SAPO-34 molecular sieve (average pore size about 0.4nm). The reaction product enters the separator after dehydration to remove C ₄ and above hydrocarbons, and the remaining low-carbon olefin gas and synthesis gas ( The volume ratio is 1:2, and the H ₂ /CO volume ratio in the synthesis gas is 1:1) are mixed together into the synthesis aldehyde reactor and contacted with the hydroformylation catalyst to produce mixed propionaldehyde and butyraldehyde.

Among them, the reaction temperature of the methanol-to-olefins reactor is 480°C, the pressure is 0.1MPa, the reaction space velocity is 4.0h ^-1 , the water-alcohol ratio is 0.2, and the composition of the dehydrated gas at the reactor outlet is shown in Table 1.

The hydroformylation catalyst is SPION-Rh catalyst, and its preparation process is similar to that of Example 6, except that [Rh(CO) ₂ Cl] ₂ is used as the active catalyst precursor.

The reaction temperature of the synthesis aldehyde reactor is 85°C and the pressure is 2.2MPa.

The results of the hydroformylation reaction are shown in Table 2.

Table 1

Table 2

Example Olefin Conversion/% Propionaldehyde selectivity/% Butyraldehyde selectivity/% Butyraldehyde isotropic ratio 1 93.6 98.2 97.1 8.5 2 95.1 97.5 99.0 10.0 3 79.4 93.8 95.2 7.9 4 89.5 99.1 98.9 9.5 5 92.2 98.4 96.3 8.1 6 97.4 99.0 99.3 4.5 7 99.8 99.5 98.9 3.9

According to the results given in Table 1 and Table 2, it can be seen that the process and catalyst provided by the present invention have good catalytic activity and high selectivity for methanol-to-olefins and further hydroformylation reactions.

Claims (8)

1. a technique for methanol-to-olefins coproduction low-carbon (LC) mixed aldehyde, it comprises the following steps:

Step one: make methanol and SAPO-34 molecular sieve haptoreaction；

Step 2: the product of step one is carried out processed circulation of qi promoting body of going forward side by side and separates, obtain containing ethylene and propylene Tail gas and liquefied petroleum gas product；

Step 3: make containing ethylene and the tail gas of propylene and H₂Mix, then with hydroformylation with the gaseous mixture of CO Catalyst haptoreaction, produces and obtains mixing propionic aldehyde and butyraldehyde；

Wherein, described hydroformylation catalyst is magnetic Nano Fe₃O₄The catalyst of the rhodium complex that granule is immobilized；

Described magnetic Nano Fe₃O₄The catalyst of the rhodium complex that granule is immobilized is through the following steps that preparation:

Surface is exposed superparamagnetic Fe of the Silica Shells of amino₃O₄Nano-particle is scattered in DMF, obtains Solution A；

Configuration concentration is the DMF solution of the EDC/HOBt of 0.4-0.8M, is sequentially added into diphenylphosphine-3-wherein Benzoic acid and tetraethylammonium chloride, obtain solution B, and mol ratio is: diphenylphosphine-3-benzoic acid: EDC/HOBt=1: 1.1-1.5, EDC/HOBt: tetraethylammonium chloride=1:1；

Solution B being added in solution A, room temperature reaction 20-24 hour, 1mg surface exposes the silicon dioxide of amino Superparamagnetic Fe of involucrum₃O₄Nano-particle or superparamagnetic Fe of 4-aminophthalic acid covering₃O₄Nano-particle pair Answer 2-10 μm ol diphenylphosphine-3-benzoic acid；

After having reacted, with Magnet by product sucking-off, it is dispersed in toluene, under nitrogen protection and stirring, adds rhodium network The toluene solution of compound, 1mg surface exposes superparamagnetic Fe of the Silica Shells of amino₃O₄Nano-particle or 4- Superparamagnetic Fe of aminophthalic acid covering₃O₄Nano-particle correspondence 0.8-2 μm ol rhodium complex, reacts 1-5h, With Magnet by product sucking-off, washing, obtain magnetic Nano Fe₃O₄The catalyst of the rhodium complex that granule is immobilized.

Technique the most according to claim 1, wherein, the reaction condition in step one is: reaction temperature is 350-550 DEG C, pressure 0.05-0.3MPa, air speed 2.0-6.0h^-1, water alcohol compares 0.1-0.3:1.

Technique the most according to claim 1, wherein, the reaction condition in step 3 is: reaction temperature is 70-120 DEG C, pressure is 1.0-3.0MPa, and the catalyst concn counted with rhodium atom is as 100-300ppm.

Technique the most according to claim 1, wherein, the reaction condition in step 3 is: containing ethylene and third The tail gas of alkene and H₂In the gas mixed with the gaseous mixture of CO, H₂It is 0.5-2.0:1 with the volume ratio of CO, alkene It is less than or equal to 1:1 with the volume ratio of synthesis gas.

Technique the most according to claim 1, wherein, the average pore size of described SAPO-34 molecular sieve is 0.2-0.6nm。

Technique the most according to claim 5, wherein, the average pore size of described SAPO-34 molecular sieve is 0.4nm.

Technique the most according to claim 1, wherein, described rhodium complex is the compound with following structure In one: Rh (acac) (CO)₂、[Rh(CO)₂Cl]₂、trans-RhCl(CO)(PPh₃)₂、RhH(CO)(PPh₃)₃、 Rh(CO)(PPh₃)(acac)；Wherein, acac represents acetylacetone,2,4-pentanedione, PPh₃Represent triphenylphosphine.

Technique the most according to claim 1, wherein, described surface exposes the super of the coated with silica of amino Paramagnetic Fe₃O₄Nano-particle through the following steps that preparation:

By 2-4mmol Fe (CO)₅, oleic acid mix with 20-25mL trioctylamine, the addition of oleic acid is Fe (CO)₅Rub 1.1 times of that amount；

Under argon gas atmosphere is protected, it is heated to 280 DEG C, reacts and obtain dark solution in 2 hours；

After removing impurity, obtain superparamagnetism Fe₃O₄Nano-particle；

It is superparamagnetic Fe of 0.05mg/mL by concentration₃O₄After the chloroformic solution concentrating under reduced pressure of nano-particle, add concentration For sodium dodecyl sulfate aqueous solution the ultrasonic disperse of 15mM, superparamagnetic Fe₃O₄The concentration of nano-particle is 0.05-0.1mg/mL；

Above-mentioned solution is placed in shaking table, adds 9 times of superparamagnetics Fe₃O₄The n-octyl trimethoxy of nanoparticle mass Silane, continues dropping and the isopyknic APTES of n-octyl trimethoxy silane, continues after shaking up Continuous reaction 48h, obtains mixed solution；

After reaction terminates, the mixed solution after reaction is positioned on Magnet, after placing 8-12h, discards solution, receive Collection precipitation is also washed, and obtains superparamagnetic Fe that surface exposes the Silica Shells of amino₃O₄Nano-particle.