Method for preparing Salen-metal complex

Abstract

The invention provides a method for preparing a Salen-metal complex. The method comprises the following steps of: under the argon atmosphere, adding ligands(II), sodium methoxide, absolute methanol soluble ligands(II) and sodium methoxide into a reactor in sequence; stirring the mixture for 2 minutes, and adding 1mol/L cobalt acetate anhydrous/ methanol solution dropwise, wherein the molar ratio of the ligands(II) to sodium methoxide to cobalt acetate is 1:1:1; and making the mixture reacted at the room temperature for 24 hours, adding anionic salt which has the same molar weight as the cobalt acetate, stirring the mixture for three days in the air, stopping the reaction, concentrating the mixture, performing dissolution and filtration by adding methylene chloride, drying the filtrate by anhydrous sodium sulfate overnight, filtering the mixture, concentrating under reduced pressure, and drying the mixture under the vacuum condition to obtain the Salen-metal complex. The Salen-metal complex prepared by the method has the advantages of simple method, low cost and high catalytic efficiency.

Description

Technical field: [0001] The invention relates to the synthesis of polycarbonate, in particular to a preparation method of a Salen-metal complex and its application in catalyzing the polymerization of carbon dioxide and epoxy compounds. Background technique: [0002] carbon dioxide (CO 2 ) is the main gas that causes the "greenhouse effect", but it is also one of the carbon resources with the largest reserves on the earth. Its reserves on the earth are more than the sum of natural gas, oil and coal. In view of the harm of carbon dioxide gas to the environment, human beings have been exploring ways to use carbon dioxide scientifically. Among them, using CO 2 Aliphatic polycarbonate copolymerized with epoxy compounds has good gas barrier properties, transparency and biodegradability, and has broad application prospects in the fields of disposable packaging materials, tableware, fresh-keeping materials, and disposable medical materials. [0003] The reported catalysts for the...

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Problems solved by technology

Lu Xiaobing et al. described a functional Salen metal complex catalytic system in CN101020747A. The functional catalyst catalyzes the polymerization of carbon dioxide and epoxy compounds to prepare polycarbonate under milder conditions and lower catalyst concentration, and the catalytic efficiency reaches 10 6 g polymer / mol catalyst, polymer molecular weight in 10 3 -10 5 The adjustable molecular weight distribution within the range is less than 2, but this patent does not clearly provide the preparation method of the catalyst. The document J.Am.Chem.Soc., 2009, 131, 11509 (Lv Xiaobing) describes and patent CN101020747A embodiment The catalyst with the highest activity is similar to the synthetic steps of the catalyst. Before the catalyst introduces 2,4-dinitrophenol anion, it needs to react with silver salt to generate an intermediate state, and then use this intermediate state to combine with 2,4-dinitrophenol anion. Sodium phenoxide reaction leads to the introduction of 2,4-dinitrophenol anion. The catalyst starts from basic organic raw materials and undergoes more than ten steps of synthesis reaction. The steps are cumbersome and the corresponding cost is high.

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