Method for preparing cyclic carbonate

Abstract

The invention discloses a method for preparing cyclic carbonate. The method specifically comprises the following step: with a quadri-aryloxy bridged rare earth metal compound as a catalyst, catalyzing carbon dioxide and alkylene oxide to react in the present of quaternary ammonium salt, wherein the general formula of the quadriaryloxy bridged rare earth metal compound is LLn(THF), wherein L refers to ethanediamine group bridged quadri-aryloxy, Ln refers to rare earth metal ions, and the quaternary ammonium salt is one of tetrabutylammonium iodide, tetrabutylammonium bromide, tetrabutylammonium chloride, tetraoctyl ammonium bromide, bis(triphenylphosphine) ammonium chloride and benzyl butyl ammonium bromide. The rare earth catalyst in the catalysis system is clear in structure, easy to synthesize, high in catalysis activity, less in using amount, mild in reaction conditions and wide in universality to alkylene oxide. According to the preparation method disclosed by the invention, raw materials are easily available, the reaction conditions are wild, a reaction substrate is wide in universality, the reaction time is short, the yield of the target product, namely the cyclic carbonate is high, and the reaction operation and the posttreatment process are simple.

Description

technical field [0001] The invention belongs to the technical field of preparation of organic compounds, and in particular relates to a preparation method of cyclocarbonate. Background technique [0002] Cyclocarbonate is a kind of good polar aprotic solvent, which can be used as the electrolyte of lithium battery, and can also be used as polymerized monomer (such as synthetic polyurethane) and pharmaceutical intermediate in industry. Therefore, it is of great application value to study the synthesis of cyclocarbonate. [0003] As a major greenhouse gas, carbon dioxide has aroused widespread concern in the society for its impact on the environment. Carbon dioxide is cheap, non-toxic, non-flammable, and rich in resources. Through the chemical conversion of carbon dioxide, the resource utilization of carbon dioxide can not only solve the problem of greenhouse effect caused by it, but also turn waste into treasure. [0004] In fact, carbon dioxide can be used as a very valua...

AI Technical Summary

Problems solved by technology

[0005] In 2001, T. Nguyen's research group reported that (Salen)Cr(III) with 1% propylene oxide molar mass and 4-(N,N-dimethyl)pyridine at 75°C and 3.5bar CO 2 Catalytic CO under pressure 2 React with propylene oxide to prepare cyclocarbonate, and the reaction can reach 100% yield in 1.5 hours, but this method is not suitable for the larger disubstituted alkylene oxide with steric hindrance, the scope of substrate application is narrow, and the catalyst consumption is relatively large (see : R. L. Paddock and S. T. Nguyen, J. Am. Chem. Soc. , 2001, 123, 11498); in 2007, Michael North's research group reported that (Salen)Al compound with 2.5% molar weight of styrene oxide and tetrabutylammonium bromide catalyzed CO 2 Reacting with styrene oxide to prepare cyclocarbonate, the reaction can reach a yield of 98% in 24 hours, but the amount of reaction catalyst is large, and the reaction is less active or inactive for the larger disubstituted alkylene oxide with steric hindrance (see: J . Meléndez, M. North, and R. Pasquale, Eur. J. Inorg. Chem., 2007, 3323); in 2010, Arjan W. Kleij's research group reported that Zn(Salphen) compound and tetrabutylammonium iodide were mixed at 45℃, 10bar CO 2 pressure, dichloromethane as a solvent to catalyze CO 2 React with 1,2-epoxyhexane to generate cyclocarbonate, and the yield can reach 80% in 18 hours. Although the reaction conditions of this system are mild, it needs toxic dichloromethane as a solvent, and the reaction is sensitive to disubstituted epoxy Alkanes are not active (see: A. Decortes, M. M. Belmonte, J. Benet-Buchholz and A. W. Kleij, Chem. Commun. , 2010, 46, 4580); in 2013, Arjan W. Kleij et al. reported that aluminum compound and tetrabutylammonium iodide reacted at 90℃, CO 2 Pressure is 10 atmospheres, catalytic CO 2 React with propylene oxide to prepare cyclocarbonate, and the yield can reach 96% in 2 hours. This system has good catalytic activity, but the synthesis and separation of the ligands used in the catalyst is relatively complicated, and the yield is only 21% (see: C. J. Whiteoak, N. Kielland, V. Laserna, E. C. Escudero-Ada?n, E. Martin and A. W. Kleij, J. Am. Chem. Soc. , 2013, 135, 1228)

[0006] The existing method can prepare cyclocarbonate, but there are deficiencies such as high pressure (greater than 10 atmospheres), high temperature (greater than 100°C), toxic solvent (such as dichloromethane), complex catalyst synthesis and low yield; and The existing reaction system has narrow substrate applicability and low or even no activity to disubstituted alkylene oxides

Images