CN112159386A

CN112159386A - Method for synthesizing cyclic carbonate by mild catalysis of ionic liquid crosslinked polymer

Info

Publication number: CN112159386A
Application number: CN202010973141.7A
Authority: CN
Inventors: 张香平; 孟祥磊; 宋婷; 刘莹; 张晓春; 张锁江
Original assignee: Institute of Process Engineering of CAS
Current assignee: Institute of Process Engineering of CAS
Priority date: 2020-09-16
Filing date: 2020-09-16
Publication date: 2021-01-01
Anticipated expiration: 2040-09-16
Also published as: CN112159386B

Abstract

The invention relates to an ionic liquid crosslinked polymer with swelling property for catalyzing CO under mild conditions₂The method for efficiently synthesizing the cyclic carbonate with the epoxide is characterized in that an ionic liquid polymer is used as a catalyst, the dosage of the catalyst is 0.5-10 mol% of the epoxide, and the cyclic carbonate is prepared by catalyzing the cycloaddition of the epoxide and carbon dioxide under the conditions of 0.1-100 bar of reaction pressure, 30-200 ℃ of reaction time and 0.5-30 h of reaction time. The method can show high-efficiency catalytic activity under normal pressure and mild reaction conditions, does not need to add a cocatalyst, and can recycle the catalyst for multiple times.

Description

Method for synthesizing cyclic carbonate by mild catalysis of ionic liquid crosslinked polymer

Technical Field

The invention relates to CO₂The technical field of green clean catalysis for resource utilization, in particular to an ionic liquid cross-linked polymer catalyst for mildly catalyzing CO₂And a method for synthesizing cyclic carbonates from epoxides.

Background

Carbon dioxide (CO)₂) Is rich, cheap and easily available and renewableC1 resource. From CO₂The research of synthesizing the cyclic carbonate by mild catalytic conversion is an effective means and an important way for converting low-carbon energy into important chemicals at present. The cyclic carbonate is a good polar solvent and is widely applied to synthesis of medicine and fine chemical intermediates.

In recent years, for catalyzing CO₂And catalysts for synthesizing carbonate ester by catalyzing epoxide, including Salen-metal complex and binary catalyst of quaternary ammonium salt (Chinese patent CN104496959A), quaternary phosphine polyion liquid (Chinese patent CN 201410392681.0), and phosphonium salt catalyst with polystyrene as carrier (Chinese patent CN 200410093952.9). However, the reported catalytic systems usually require high temperature (more than 120 ℃) and high pressure (more than 2MPa) to be successfully completed, and even some catalytic systems need to add additional cocatalyst and solvent, thereby greatly increasing the production cost and the risk factor. Meanwhile, the reported homogeneous catalysts have relatively high activity, but the recovery process usually needs a series of high energy consumption operations such as vacuum rectification and the like. Although the heterogeneous catalyst can be easily recovered, its catalytic activity is still low even under relatively high-temperature and high-pressure reaction conditions. Therefore, the invention provides a simply prepared cross-linked polymerization ionic liquid catalyst which can effectively dissolve CO₂And has good swelling effect on epoxide. The homogeneous reaction atmosphere formed in the network structure can efficiently catalyze carbon dioxide and epoxide to synthesize cyclic carbonate under mild reaction conditions.

Disclosure of Invention

The invention researches a method for efficiently catalyzing and synthesizing cyclic carbonate by using an ionic liquid cross-linked polymer as a catalyst under the mild reaction conditions of carbon dioxide and epoxide in a mild reaction atmosphere without any cocatalyst.

The general formula of the reaction is:

when R is₂When H is represented, the epoxy compound used in the formulaThe structure of the compound is:

wherein n is 0 to 6, and X is Cl or Br.

The invention relates to ionic liquid crosslinked polymer catalyzed CO₂And a method for preparing cyclic carbonate by epoxide, which is characterized in that cross-linked polymerization ionic liquid with swelling performance is used as a catalyst, the dosage of the catalyst is 0.5-10 mol% of epoxide, and the cyclic carbonate is prepared by catalyzing epoxide and carbon dioxide cycloaddition under the conditions of reaction pressure of 0.1-100 bar, temperature of 30-200 ℃ and reaction time of 0.5-30 h. The method can show high-efficiency catalytic activity under normal pressure and mild reaction conditions, no additional cocatalyst is required to be added, and the catalyst can be simply recovered and recycled for multiple times. The structure of the ionic liquid crosslinked polymer related by the invention is as follows:

any one of them. Wherein X is one of Cl, Br and I halogen groups, and Br and Cl are preferably selected.

The present invention is described below with reference to examples, but the present invention is not limited to the technical scope of the examples, and falls within the technical scope of the present invention without departing from the spirit of the invention described above.

Detailed Description

Example 1 Synthesis of Ionic liquid crosslinked Polymer d

The cross-linked polymeric ionic liquid of the present invention was prepared by a two-step process, first, 0.53mmol of azobisisobutyronitrile was dissolved in a flask containing 10mL of N, N-dimethylformamide solution, and then the monomers 1-vinylimidazole (20mmol) and butyl acrylate (20mmol) were added to the flask. After removal of air by bubbling nitrogen for 20min, the mixture was stirred at 70 ℃ for 10h under nitrogen blanket. After completion of the reaction, the crude product was obtained by precipitation in ether, and then re-purified in ether using ethanol as a solvent, and the obtained product was dried in a vacuum oven for 24 h. Other copolymers were synthesized in the same manner by varying the ratio of the reactants. The obtained copolymer (1.5g, n ═ 3.0mmol) was dissolved in ethanol (12 mL). 1, 6-dibromohexane (0.12g, 0.5mmol) and 1-bromobutane (0.13g, 1mmol) were then added to the mixture. The mixture solution was degassed by sonication for 10min and cast in a teflon mold. The solvent of the casting solution was evaporated at room temperature overnight and then dried in a vacuum oven at 65 ℃ for 12 h. Finally, the obtained polymeric ionic liquid membrane was ground to a powder in liquid nitrogen for use. Other ionic liquid crosslinked polymers were synthesized in the same manner by varying the ratio of reactants.

Example 2

In a 20mL Schlenk tube, 0.5mL of epichlorohydrin (1a) and 2 mol% of polymeric ionic liquid f are sequentially added, the temperature is controlled by a temperature controller to be stabilized to 50 ℃, a carbon dioxide-filled bladder is connected to the Schlenk tube, and CO is introduced₂Reacting for 12h, cooling to room temperature, taking off carbon dioxide bladder, and using CDCl₃As a solvent in¹HNMR nuclear magnetic spectroscopy characterized the yield of the product. The selectivity of product 2a was greater than 99% with a yield of 76%.

Example 3

As in example 2, the reaction time was 24 hours and other reaction conditions were unchanged, giving a yield of 90% of product 2 b.

Example 4

As in example 2, the yield of the product 2b was 68% with the ionic liquid crosslinked polymer d and the other reaction conditions unchanged

Example 5

In the same manner as in example 2, the ionic liquid crosslinked polymer used was c, and other reaction conditions were unchanged, to obtain the product 2b in a yield of 54%.

Example 6

In the same manner as in example 2, the amount of catalyst used was 3 mol% based on the amount of epichlorohydrin, and the other reaction conditions were unchanged, giving a yield of product 2b of 66%.

Example 7

As in example 2, the reaction time was 30 hours, and other reaction conditions were unchanged, giving a yield of 92% of product 2 b.

Example 8

As in example 2, the epoxide used was bromopropylene oxide (1b), and the other reaction conditions were unchanged to give the product 2b in 82% yield.

Example 9

In the same manner as in example 2, the epoxide used was propylene oxide butyl ether (1c), the catalyst used was 4 mol% of propylene oxide butyl ether, the reaction time was 24h, and the other reaction conditions were unchanged to give the product 2c in a yield of 85%.

Example 10

As in example 2, the epoxide used was 1-allyloxy-2, 3-epoxypropane (1d), the catalyst used was 4 mol% of 1d, the reaction time was 24h, and the other reaction conditions were unchanged to give the product 2d in 87% yield.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention. Therefore, it is intended that the present invention covers such modifications and variations as fall within the true scope of the invention.

Claims

1. A method for synthesizing cyclic carbonate by ionic liquid cross-linked polymer mild catalysis is characterized in that epoxide and carbon dioxide are used as reactants, a catalyst is selected from one of cross-linked polyionic liquid, the dosage of the catalyst is 0.5-10 mol% of the epoxide, and the cyclic carbonate is synthesized under the conditions of reaction pressure of 0.1-100 bar, temperature of 30-200 ℃ and reaction time of 0.5-30 h.

2. The method of claim 1, wherein the ionic liquid cross-linked polymer has the following structure:

。

3. the method of synthesis of claim 1, the starting epoxide having the structure:

any one of them.

4. A process according to claim 3, wherein X is any one of Cl, Br, I halogen groups, preferably Br and Cl.