Catalyst capable of regulating and controlling molecular weight of ethylene oxide and preparation method thereof

Abstract

The invention relates to a catalyst capable of regulating and controlling the molecular weight of ethylene oxide and a preparation method thereof. The preparation method of the catalyst includes the steps that liquid ammonia reacts with calcium metal for 0.5-4 h at low temperatures of minus 80 DEG C to minus 10 DEG C to generate an ammonia-calcium complex solution, after a modifying agent composedof propylene oxide and azo compounds is added into solvent, reaction continues for 0.5-4 h, and through heating deamination and aging, the catalyst is obtained. Compared with the prior art, the prepared catalyst has the advantages of being high in activity and stability and capable of adjusting the molecular weight of polymers, and during the ring opening polymerization reaction of ethylene oxide(EO), polyoxyethylene series products of which the molecular weights are 100 thousand to 200 million can be prepared.

Description

technical field [0001] The invention relates to a catalyst, in particular to a method for preparing a catalyst for catalyzing the ring-opening polymerization of ethylene oxide to generate polyethylene oxide, which can synthesize a series of polyethylene oxide with a molecular weight of 100,000 to 2 million. Background technique [0002] Polyethylene oxide (PEO) is a linear polymer formed by heterogeneously catalyzed ring-opening polymerization of ethylene oxide. It is a crystalline, thermoplastic, and water-soluble polymer with low chemical toxicity. Depending on the degree of polymerization, the molecular weight of polyethylene oxide can vary from 100,000 to 8 million. In addition to the above properties, PEO also has a series of other excellent properties at different molecular weights, and can act as a dispersant, flocculant, thickener, hydraulic drag reducer, etc. It is widely used in many fields such as medicine and industrial engineering. In recent years, with the in...

AI Technical Summary

Problems solved by technology

The U.S. patent (US2006036066) mentions the blending of organoaluminum compounds and alkali metal oxides or hydroxides, and the obtained catalyst can prepare polyethylene oxide with a molecular weight of 20,000 to 200,000. However, the process is complicated and involves high-pressure operation. high equipment requirements

Chinese patent (CN 1306023A) is a catalyst synthesized by dissolving metal calcium in liquid ammonia, adding modifiers and aluminum oxide and other carriers. The catalyst has the characteristics of low temperature, high activity and high yield. The prepared polyoxygen The molecular weight of ethylene reaches 8 million, which is not suitable for the preparation of low molecular weight PEO products

But the catalytic stability of the catalyst mentioned in the patent CN 101392053A is relatively poor, and the polymerization yield of ethylene oxide fluctuates between 60%~98%; The catalyst mentioned in the patent (CN 101407579A) can only prepare molecular weight is 80 Polyethylene oxide between 10,000 and 3 million cannot be synthesized with lower molecular weight polyethylene oxide

Chinese patent (CN 103539931 A) reported alkaline earth metal calcium-ammonia-modifier catalyst system, the modifier is composed of propylene oxide and acetonitrile, and aging treatment is carried out to the suspension catalyst, and the prepared molecular weight is between 600,000 PEO between 1.6 million and 1.6 million, but the catalyst prepared by this patent cannot synthesize PEO with a molecular weight between 100,000 and 600,000