Process for preparing polycarbonate with optical activity

Abstract

The invention provides a method for preparing polycarbonate with optical activity by catalyzing asymmetric alternative copolymerization with racemic oxiraneic hydrocarbon and carbon dioxide, employing bi-component catalyst with chirality catalyzing the antimer of the racemic oxiraneic hydrocarbon selectively at the temperature of 0~80 DEG C, and copolymarizating with carbon dioxide to preparepolycarbonate with optical activity. The bi-component catalyst consists of host catalyst, the chirality quadridentate schiff bases metallic complexe, SalenMX; and the catalyst promoter, the salt of R1R23YX1 or (R13P)2YX1, with the proportion in moles 0.2~10:1. The proportion between catalyst and oxiranic hydrocarbon is 1:500~10000 in moles, the initial pressure of carbon dioxide is 0.1~4.0 Mpa, and the reacting for 0.5~24 hours. The method is characterized by the temperate reaction condition and the simple process; the simple synthesis of the chirality catalyst and low production cost and high reactive and suitable for industrial application.

Description

technical field [0001] The invention relates to a method for preparing optically active polycarbonate with high efficiency, convenience and mild reaction conditions. Background technique [0002] Carbon dioxide is the main gas that causes the greenhouse effect, and it is also one of the most abundant carbon sources on earth. The chemical fixation of carbon dioxide is an important research field of green chemistry. Among them, a main direction of utilizing carbon dioxide is to prepare polycarbonate by copolymerizing it with alkylene oxide under the action of a catalyst. The high polymer can be photodegraded and biodegraded; meanwhile, it has excellent performance of blocking oxygen and water. Therefore, polycarbonate can be used as engineering plastics, biodegradable non-polluting materials, disposable medical and food packaging materials, adhesives, and composite materials. Optically active polycarbonates are expected to have important applications in the high-tech field ...

AI Technical Summary

Problems solved by technology

Japanese published patents JP 02142824 and JP 02575199 use expensive porphyrin complexes to catalyze carbon dioxide and alkylene oxide to synthesize polycarbonate, and the catalytic efficiency reaches 103~104 grams of polymer / mol catalyst, but the molecular weight of the polymer is only about 5000, and the reaction It takes more than 10 days

Chinese patent application numbers CN 89100701.6 and CN 91109459.8 disclose a bimetallic catalyst system with polymer-loaded anion coordination, which can also obtain a catalytic efficiency of 104 grams of polymer / mol catalyst, but the carrier is difficult to separate from the polycarbonate produced

In U.S. Patent US 6133402 and J.Am.Chem.Soc., (2002, 124, 14284), Coates described a highly active single-site organozinc catalyst with catalytic activity for the reaction of carbon dioxide and propylene oxide As high as 235 moles of product / mole of catalyst per hour, polypropylene carbonate with a molecular weight between 20,000 and 40,000 and a narrow distribution is obtained, but at the same time, 13 to 25% of cyclic propylene carbonate by-products are produced

[0004] Most of the above methods for preparing polycarbonate have low catalyst activity, long reaction time, high pressure, and the need for organic solvents; accompanied by the production of cyclic carbonate by-products or low carbonate units in the polymerization product; difficulty in separating the product from the catalyst, etc. question

More importantly, these literatures have not yet dealt with the synthesis of optically active polycarbonate

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