CN115504954A

CN115504954A - Method for catalytically synthesizing cyclic carbonate based on high ion density polyion liquid

Info

Publication number: CN115504954A
Application number: CN202211280968.5A
Authority: CN
Inventors: 成卫国; 赵茜萌; 苏倩; 付梦倩; 邓莉莉; 董丽; 刘一凡; 杨子锋; 张锁江
Original assignee: Huizhou Green Energy And New Materials Research Institute; Institute of Process Engineering of CAS
Current assignee: Huizhou Green Energy And New Materials Research Institute; Institute of Process Engineering of CAS
Priority date: 2022-10-19
Filing date: 2022-10-19
Publication date: 2022-12-23

Abstract

The invention provides a preparation method of a high-ion-density polyion liquid catalyst and a method for preparing cyclic carbonate by catalyzing CO2 and epoxy compounds, wherein two imidazolyl monomers are copolymerized according to a certain proportion, the reaction can realize high-efficiency conversion of CO2 and epoxy compounds in a short time under the condition of small dosage of ionic liquid, and the catalyst has the advantages of good stability and easiness in separation. The yield of the product cyclic carbonate obtained by the catalytic reaction of the catalyst can reach 98 percent. The catalysis process has the following advantages that the CO2 is efficiently converted through the design of the high-ion-density polyion liquid, and meanwhile, the separation is easy, and the catalysis process has a good application prospect.

Description

Method for catalytically synthesizing cyclic carbonate based on high ion density polyion liquid

The technical field;

the invention relates to the technical field of green and clean synthesis of organic chemicals, in particular to synthesis of high-ion-density polyion liquid and a method for preparing cyclic carbonate ester by catalysis of the high-ion-density polyion liquid.

Technical background:

the CO2 has the advantages of no toxicity, richness, low price and the like, is a C1 resource with great application prospect, is captured and converted into a high-value chemical, and has important significance for relieving the negative influence of the CO2 on climate change and reducing the dependence on fossil energy. Among various CO2 capture conversion technologies, CO2 synthesis of cyclic carbonates is one of the most promising approaches.

For the preparation of cyclic carbonates from CO2, the conversion of CO2 is usually carried out under high temperature and pressure and the action of a catalyst. From the viewpoint of energy conservation and environmental protection, the development of the catalyst is key to realize the high-efficiency conversion of CO2 under mild conditions. The catalysts for synthesizing cyclic carbonate reported at present can be divided into homogeneous catalysts and heterogeneous catalysts, and the homogeneous catalysts mainly refer to homogeneous catalytic systems composed of halogen anions and lewis acids, such as imidazole ionic liquids, quaternary ammonium salts, lewis acid metal complexes, quaternary phosphonium salts and the like. However, in general, a homogeneous catalyst is difficult to separate after completion of the reaction, is expensive, and requires an organic solvent which is harmful to the environment to be used in the separation process, and thus is difficult to be applied to industrial applications.

The heterogeneous catalyst is difficult to dissolve in a reaction system, so that the heterogeneous catalyst has the advantage of easy separation from a product, and becomes a research focus in the field of catalytic synthesis of cyclic carbonate. The heterogeneous catalysts developed at present mainly comprise ion exchange resin supported catalysts, alkali metal salt supported catalysts, quaternary phosphonium salt supported system catalysts and the like, and the heterogeneous catalysts using supported quaternary ammonium salt catalysts, supported metal catalysts and the like generally have the defects of complex synthesis, large using amount, long reaction time, short service life, low activity and the like in the reaction. For example, CN 113441183A discloses an alkali metal ion-loaded crown ether organic polymer, which is catalyzed and synthesized by adopting crown ether and alkali metal ion to form a stable complex to synthesize cyclic carbonate, the reaction is carried out under mild conditions, the yield is high, the activity is good, but the reaction time is long. CN 113117747A discloses an interfacial ionic liquid supported catalyst for synthesizing cyclic carbonate from CO2, which is synthesized by adopting ionic liquid, zinc halide and mineral materials. The catalyst is low in price and easy to prepare, but the conversion rate of the catalyst is low, and the dosage is large. The invention discloses CN 113582963A, which relates to a method for preparing cyclic carbonate by cycloaddition of CO2 and epoxide under the catalysis of a Merrifield resin supported polyether amide ionic liquid catalyst.

Active components are immobilized in different carriers in the modes of chemical loading or physical confinement and the like, so that the simple separation and recycling of the catalyst are realized, and the problem of active component loss still exists. Besides the method, the homogeneous ionic liquid catalyst can be converted into a heterogeneous catalyst in a polymerization mode, so that the separation process of the catalyst is simplified, the loss of the catalyst is reduced, and the method is easy to popularize and apply. For example, CN 113896704A reports a method for catalytically synthesizing cyclic carbonate by using porous self-polymerization ionic liquid, in which CO2 and an epoxy compound are used as reactants, and porous self-polymerization ionic liquid is used as a catalyst to catalytically synthesize cyclic carbonate. The high-efficiency conversion of CO2 and epoxide under mild conditions is realized, no cocatalyst is needed, the reaction time is long, and the catalytic activity is not high.

Therefore, there is still a need for a green catalyst having the coexistence of advantages such as activity, selectivity and stability for the cycloaddition reaction of an epoxide and CO2 to form a cyclic carbonate. The invention aims to design a series of polyion liquid to realize high-efficiency stable conversion of carbonylation reaction.

The invention is disclosed;

the invention provides a method for catalytically synthesizing cyclic carbonate based on a high ion density polyion liquid. The cyclic carbonate is prepared by adopting high ion density ionic liquid as a catalyst and an epoxy compound as a raw material, wherein the molar ratio of the addition amount of the catalyst ionic liquid to epoxide is 0.03-1.0%, the reaction temperature is 30-180 ℃, the reaction pressure is 0.1-8MPa, and the reaction time is 0.25-12h. The polyion liquid catalyst with a specific structure is designed by adopting high ion density, so that the catalytic conversion frequency can be improved, the reaction time can be shortened, and the consumption of the catalyst and the energy consumption can be reduced.

The structure of the ionic liquid adopted by the invention is one or the combination of at least two of the structures shown in formula I, formula II, formula III and formula IV.

Wherein m and n are independently selected from any natural number, and m + n is more than or equal to 4; R1-R7 are at least one independently selected from substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C2-C6 alkenyl, substituted or unsubstituted C2-C6 alkynyl, substituted or unsubstituted C6-C30 aryl, carboxyl, hydroxyl, halogen and amino; x is any one of chloride ion, bromide ion, iodide ion, lactate, trifluoroacetate, carboxylate radical, sulfate radical, hydrogen sulfate radical, nitrite radical, tetrafluoroborate radical and the like; the term "C2-C10 alkenyl group" means a straight or branched chain alkenyl group having 2, 3, 4,5, 6, 7, 8, 9, 10 carbon atoms, which includes at least one double bond in the molecular chain, and may include-CH = CH2, -CH = CH (CH 3), -CH = C (CH 3) 2, -C (CH 3) = CH (CH 3), -C (CH 3) = C (CH 3) 2, n-pentenyl, isohexenyl, m-heptenyl, n-octenyl and the like. The term "C2-C10 alkynyl" refers to straight or branched chain alkynyl groups having 2, 3, 4,5, 6, 7, 8, 9, 10 carbon atoms, examples thereof include-C.ident.CH, -C.ident.C (CH 3), -C.ident.C (CH 2) 2CH3, - (CH 2) 2 C.ident.C (CH 3) - (CH 3CHCH 2) C ≡ C (CH 3) or-CH 2C ≡ C (CH 2) 2CH3, etc. X is any one of chlorine, bromine, iodine, lactate, trifluoroacetate, carboxylate, sulfate radical, hydrogen sulfate radical, nitrite and tetrafluoroborate; preferably, the catalyst is any one of the following compounds:

preferably, it is

The polyion liquid synthesis process comprises the steps of presetting the temperature to be 50-100 ℃, controlling the reaction time to be 3-60 hours, adopting inert gas for protection, and generally selecting nitrogen for protection from the economic point of view. After the ionic liquid monomer is synthesized, washing is carried out through reduced pressure suction filtration or rotary evaporation, and after washing, the ionic liquid monomer is put into a vacuum drying oven and vacuumized, and the temperature is set to be 50-80 ℃. The obtained ionic liquid monomer and vinyl imidazole polyionic liquid are initiated to copolymerize through AIBN, the temperature is set to be 80-130 ℃, the polymerization time is 4-20h, and inert gas is adopted for protection. And (3) washing the synthesized polyion liquid by decompression suction filtration or rotary evaporation, putting the washed polyion liquid into a vacuum drying oven, and vacuumizing at the temperature of 50-80 ℃.

The general reaction formula of the invention is:

wherein R is one of substituted or unsubstituted C1-C20 straight chain or branched chain alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C3-C20 heterocycloalkyl and substituted or unsubstituted C6-C20 aryl. Preferably, the epoxy compound of the present invention is selected from at least one or two combinations of ethylene oxide, propylene oxide, epichlorohydrin, cyclohexene oxide, styrene oxide, and the like.

Preferably, the cyclic carbonate is selected from at least one or two of ethylene carbonate, propylene carbonate, epoxy chloropropene, epoxy cyclohexene, and styrene carbonate.

Preferably, the molar ratio of the ionic liquid to the epoxy compound is 0.03 to 1.0%, and may be, for example, 0.03%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, or the like, preferably 0.03 to 0.3%.

The operating pressure of the catalytic reaction is preferably 0.1 to 8MPa, and may be, for example, 0.1MPa, 0.5MPa, 1.0MPa, 1.5MPa, 2.0MPa, 2.5MPa, 3.0MPa, 3.5MPa, 4.0MPa, 4.5MPa, 5.0MPa, 5.5MPa, 6.0MPa, 6.5MPa, 7.0MPa, 7.5MPa or 8.0MPa, and is preferably 2 to 4MPa.

Preferably, the catalytic reaction temperature is 30-180 ℃, for example can be 30 degrees C, 40 degrees C, 50 degrees C, 60 degrees C, 70 degrees C, 80 degrees C, 85 degrees C, 90 degrees C, 95 degrees C, 100 degrees C, 105 degrees C, 110 degrees C, 115 degrees C, 120 degrees C, 125 degrees C, 130 degrees C, 135 degrees C, 140 degrees C, 145 degrees C, 150 degrees C, 155 degrees C, 160 degrees C, 165 degrees C, 170 degrees C, 175 degrees C or 180 degrees C, preferably 100-130 ℃.

Preferably, the reaction time of the catalytic reaction is 0.25 to 12 hours, and may be, for example, 0.25 hour, 0.5 hour, 1 hour, 1.5 hour, 2 hours, 2.5 hours, 3.0 hours, 3.5 hours, 4.0 hours, 4.5 hours, 5.0 hours, 5.5 hours, 6.0 hours, 8.0 hours, 10.0 hours, 12.0 hours, or the like, preferably 0.5 to 3 hours.

And stopping stirring after the reaction is finished, cooling the temperature in the reaction kettle to room temperature, disassembling the kettle, and sucking the upper-layer liquid to obtain the required cyclic carbonate ester product.

The method of the invention has the advantages that:

the polyion liquid structure is designed with high ion density, and has higher activity compared with the common polyion liquid with equal molar mass.

The invention adopts high ion density ionic liquid as the catalyst of the carbonylation reaction, and the addition of the catalyst can lead the reaction to achieve high-efficiency conversion in a short time, reduce the reaction energy consumption and accord with the principle of green economy and environmental protection.

Description of the drawings;

FIG. 1 is a 1H-NMR spectrum of Ply [ PhSVIM ] Br obtained in example 1 of the present invention.

A specific embodiment;

the technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

1. Preparation of high ion density polyion liquid

Example 1

The example is a high ion density ionic liquid catalyst synthesized with the following specific structure:

0.40g (0.6 mmol) of hexabromotoluene was weighed into a 50mL round-bottom flask, 4.8mmol of vinylimidazole and 15mL of acetonitrile were added, and the mixture was reacted at 65 ℃ for 60 hours. After the reaction was completed, the product was washed with anhydrous ethyl acetate three times (150 ml each). After washing, the product was dried in a vacuum oven at 50 ℃ for 12h.

0.6g (0.5 mmol) of the obtained ionic liquid monomer was weighed out and placed in a 50ml three-necked flask together with 0.1 (0.5 mmol) of 1-ethylvinylimidazole, 30ml of acetonitrile and 0.0045g (6 mol%) of AIBN were added, and the mixture was reacted for 15h under N2 protection at 85 ℃. After the reaction was completed, the product was washed with anhydrous ethyl acetate and deionized water three times with 150ml each time. After washing, the product was dried in a vacuum oven at 50 ℃ for 12h.

Example 2

The example is to synthesize a high ion density polyion liquid, and the specific structure is as follows:

synthetic method referring to example 1, only hexabromotoluene was changed to 1,2,4, 5-tetrakis (1-methyl-3-vinylimidazolium bromide) benzene ([ PhFVIM ] Br).

Example 3

synthetic method referring to example 1, only hexabromotoluene was changed to 1,3, 5-tris (1-methyl-3-vinylimidazolium bromide) benzene ([ PhTVIM ] Br).

Example 4

The example is to synthesize a multi-center ionic liquid catalyst, and the specific structure is as follows:

synthetic procedure with reference to example 1, only hexabromotoluene was changed to 1, 4-bis (1-methyl-3-vinylimidazolium bromide) benzene ([ PhDVIM ] Br).

2. Synthesis of cyclic carbonate by carbonylation of epoxy compound

Example 5

This example provides a method for the catalytic synthesis of cyclic carbonates, the specific reaction is shown below:

2g of Propylene Oxide (PO) and 0.034mol of Ply [ PhSVIM ] Br are added to the reactor; filling a proper amount of CO2 at room temperature, and closing a vent valve of the reaction kettle; putting a reaction kettle into an automatic temperature control heating furnace, adjusting the pressure of the reaction kettle to 1MPa, keeping the temperature to 120 ℃ after the temperature rises to a target temperature for about 15min, adjusting the pressure of the reaction kettle to 3MPa, keeping the CO2 pressure at 3MPa, reacting for 2h at 120 ℃, placing the reaction kettle in an ice water bath to cool to room temperature after the reaction is finished, slowly discharging residual gas, taking out a trace reaction liquid, analyzing the conversion rate and the selectivity by Agilent 8890, and measuring that the yield of the product propylene carbonate is 96.2 percent and the selectivity is 99.9 percent.

Example 6

The difference between the example and the example 5 is that the reaction temperature is changed to 130 ℃, other conditions are not changed, and the yield of the propylene carbonate product is 98.3%, and the selectivity is 99.9%.

Example 7

The difference between the example and the example 5 is that the reaction pressure is changed to 2MPa, other conditions are not changed, and the yield of the propylene carbonate product is 96.1 percent, and the selectivity is 99.9 percent.

Example 8

The difference between the example and the example 5 is that the reaction pressure is changed to 3MPa, other conditions are not changed, and the yield of the propylene carbonate product is 97.8 percent, and the selectivity is 99.9 percent.

Example 9

This example differs from example 5 in that the catalyst addition was changed to 15mg and other conditions were not changed to give the product propylene carbonate in 54.4% yield and 99.9% selectivity.

Example 10

The difference between the embodiment and the embodiment 5 is that the adding amount of the catalyst is changed to 20mg, other conditions are not changed, and the yield of the product propylene carbonate is 61.7%, and the selectivity is 99.9%.

Example 11

The difference between the embodiment and the embodiment 5 is that the adding amount of the catalyst is changed to 30mg, other conditions are not changed, and the yield of the product propylene carbonate is 70.5%, and the selectivity is 99.9%.

Example 12

This example differs from example 5 in that the amount of catalyst added was changed to 40mg and the other conditions were not changed to obtain the product propylene carbonate with a yield of 81.5% and a selectivity of 99.9%.

Example 13

This example differs from example 5 in that the catalyst addition was changed to 80mg and other conditions were not changed to give the product propylene carbonate in 86.4% yield and 99.9% selectivity.

Example 14

The difference between the example and the example 5 is that the reaction time is changed to 30min, other conditions are not changed, and the yield of the propylene carbonate product is 51.9%, and the selectivity is 99.9%.

Example 15

The difference between the example and the example 5 is that the reaction time is changed to 60min, other conditions are not changed, and the yield of the propylene carbonate product is 90.7%, and the selectivity is 99.9%.

Example 16

The difference between the example and the example 5 is that the reaction time is changed to 90min, other conditions are not changed, and the yield of the propylene carbonate product is 92.8%, and the selectivity is 99.9%.

Example 17

This example differs from example 5 in that the epoxy compound used was epichlorohydrin and that the other conditions were unchanged, giving a chloropropene carbonate product with a yield of 93.8% and a selectivity of 99.9%.

Example 18

This example differs from example 5 in that the epoxide compound used was ethylene oxide, and other conditions were unchanged, resulting in a product ethylene carbonate yield of 96.5% and a selectivity of 99.9%.

Example 19

This example differs from example 5 in that the epoxy compound used was styrene oxide and the other conditions were otherwise unchanged, resulting in a styrene carbonate product yield of 75.7% and a selectivity of 99.9%.

Example 10

The difference between the embodiment and the embodiment 5 is that the epoxy compound used is methyl propylene oxide, the reaction time is changed to 2h, other conditions are not changed, the yield of the product methyl propylene carbonate is 89.8%, and the selectivity is 99.9%.

Comparative example 1

This example differs from example 5 in that the catalyst used was polyhexamethylene (1-methyl-3-vinylimidazolium bromide) benzene, and other conditions were unchanged to give the product propylene carbonate in 88% yield and 99.9% selectivity.

Comparative example 2

The difference between the comparative example and the comparative example 1 is that the catalyst is poly (1, 4-bis (1-methyl-3-vinyl imidazole bromide) benzene, other conditions are not changed, the yield of the product propylene carbonate is 77%, and the selectivity is 99.9%.

Comparative example 3

The difference between the comparative example and the comparative example 1 is that the catalyst used is poly 1,3, 5-tri (1-methyl-3-vinyl imidazole bromide) benzene, other conditions are not changed, the yield of the propylene carbonate product is 76%, and the selectivity is 99.9%.

Comparative example 4

This example differs from comparative example 1 in that the catalyst used was poly 1,2,4, 5-tetrakis (1-methyl-3-vinylimidazolium bromide) benzene and other conditions were unchanged to give the product propylene carbonate in 86% yield and 99.9% selectivity.

The applicant states that the present invention is described by the above embodiments to explain the detailed structural features of the present invention, but the present invention is not limited to the above detailed structural features, that is, it is not meant to imply that the present invention must be implemented by relying on the above detailed structural features. It will be understood by those skilled in the art that various changes in the embodiments and modifications described in the foregoing detailed description may be made, and equivalents may be substituted for elements thereof without departing from the scope of the invention.

Claims

1. A high ion density polyion liquid catalyst is characterized in that the polyion liquid has a structure shown as a formula I, II, III or IV:

wherein m and n are each independently selected from any natural number, and m + n is not less than 4; R1-R7 are at least one independently selected from substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C2-C6 alkenyl, substituted or unsubstituted C2-C6 alkynyl, substituted or unsubstituted C6-C30 aryl, carboxyl, hydroxyl, halogen and amino; x is any one of chloride ion, bromide ion, iodide ion, lactate, trifluoroacetate, carboxylate, sulfate radical, hydrogen sulfate radical, nitrite, tetrafluoroborate radical and the like;

2. the method for preparing the high ion density polyion liquid catalyst according to claim 1, comprising the steps of:

(1) The preset temperature is 50-100 ℃, the reaction time is 3-60h, inert gas is adopted for protection, and nitrogen is generally selected for protection from the economical point of view. After the ionic liquid monomer is synthesized, washing is carried out through reduced pressure suction filtration or rotary evaporation, and after washing, the ionic liquid monomer is put into a vacuum drying oven and vacuumized, and the temperature is set to be 50-80 ℃.

(2) The obtained ionic liquid monomer and vinyl imidazole polyionic liquid are initiated to copolymerize through AIBN, the temperature is set to be 80-130 ℃, the polymerization time is 4-20h, and inert gas is adopted for protection. And (3) washing the synthesized polyion liquid by decompression suction filtration or rotary evaporation, putting the washed polyion liquid into a vacuum drying oven, and vacuumizing at the temperature of 50-80 ℃.

3. A method for synthesizing cyclic carbonate by catalyzing CO2 and epoxide with polyion liquid with high ion density is characterized in that, preferably, the mole ratio of the addition amount of the polyion liquid as catalyst to epoxide is 0.03-10%;

preferably, the catalytic reaction temperature is 30-180 ℃;

preferably, the catalytic reaction pressure is 0.1-8Mpa;

preferably, the catalytic reaction time is 0.25 to 12 hours.

4. The method of claim 3, wherein the catalytic reaction has the general formula:

wherein R is one of substituted or unsubstituted C1-C20 linear or branched alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C3-C20 heterocycloalkyl, and substituted or unsubstituted C6-C20 aryl.

5. The process according to claim 4, wherein the epoxy compound is at least one selected from the group consisting of ethylene oxide, propylene oxide, epichlorohydrin, cyclohexene oxide, styrene oxide, etc.

6. The process according to claim 1, wherein in the structures of formulae I, II, III and IV, the number of carbon atoms in the R1 to R7 groups is from 0 to 35, preferably from the group consisting of substituted or unsubstituted alkyl, aryl, carboxyl, hydroxyl, halogen, amino, etc.

7. The production method according to claim 1, wherein the anion X in the structures represented by formulas I, II, III and IV is selected from any one of chloride, bromide, iodide, lactate, trifluoroacetate, carboxylate, sulfate, hydrogensulfate, nitrite, tetrafluoroborate and the like.

8. The preparation method according to claim 3, wherein the molar ratio of the ionic liquid catalyst to the epoxide is 0.03-10%, and preferably the catalyst is 0.03-1mol%.

9. The method of claim 1 to 9, comprising the steps of: placing the epoxy compound and 0.03-1mol% of catalyst powder in a closed high-pressure reaction kettle, uniformly mixing, maintaining the temperature of the reaction kettle within the range of 30-180 ℃, continuously introducing CO2 gas into the reaction kettle, maintaining the pressure of a reaction system in the kettle within the range of 0.1-8MPa, and performing addition reaction for 0.25-12h to obtain the cyclic carbonate.