Single site catalyst for synthesizing polycarbonate

Abstract

The invention discloses a high-activity catalyst which catalyzing and activating carbon dioxide to perform the copolymerization reaction with alkylene oxide to synthesize polycarbonate. The catalyst is characterized in that the catalyst is a tetradentate schiff base complex contains one or two organic base groups and has single active site initiation and controllable polymerization. The catalyst has the advantages that under milder conditions and at lower concentration of the catalyst, the catalyst can highly and efficiently catalyze the carbon dioxide to make the copolymerization reaction with the alkylene oxide to prepare the polycarbonate, the catalytic efficiency is 10<6>g polymer / mol catalyst, the polymer molecular weight is adjusted in the range of between 5,000 and 500,000, the molecular weight distribution is less than 2, the alternating structure is over 97 percent, and the catalyst can be degraded into small molecule compounds under certain condition. By utilizing the catalyst, the telomerization reaction between the carbon dioxide and two or more than two types of alkylene oxide can be catalyzed to synthesize a polycarbonate telomer with adjusting glass transition temperature.

Description

technical field [0001] The invention relates to a catalyst for synthesizing polycarbonate, in particular to a high-activity single-active point catalyst for synthesizing polycarbonate by catalytically activating carbon dioxide and alkylene oxide. 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. Under the action of catalyst, carbon dioxide can be copolymerized with alkylene oxide to prepare biodegradable polycarbonate. The high polymer has excellent oxygen and water barrier properties, and can be used as engineering plastics, biodegradable non-polluting materials, disposable medicine and food packaging materials, adhesives and composite materials, etc. [0003] At present, there are many patent reports on the preparation of polycarbonate by copolymerization of carbon dioxide...

AI Technical Summary

Problems solved by technology

Chinese patent application numbers: CN 89100701.6 and CN 91109459.8 disclose a bimetallic catalyst system supported by polymers with anion coordination, and can also obtain 10 4 Catalytic efficiency in grams of polymer per mole of catalyst, but the support is difficult to separate from the resulting polycarbonate

[0004] Most of the above-mentioned methods for preparing polycarbonate have low catalyst activity, long reaction time, and high pressure, which requires an organic solvent; accompanied by the production of cyclic carbonate by-products or low carbonate units in the polymerization product; the catalyst and reaction in the reaction system The molar ratio of the substrate is high; the separation of the product and the catalyst is difficult, etc.

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