Method for synthesizing trioxymethylene by catalyzing formaldehyde cyclization reaction through bifunctional ionic liquid

Abstract

The invention discloses a method for synthesizing trioxymethylene by catalyzing cyclization reaction of aqueous solution of formaldehyde through bifunctional ionic liquid. In the method, the bifunctional ionic liquid is taken as a catalyst, a mode of catalytic rectification reaction is adopted, and the trioxymethylene is prepared through the formaldehyde cyclization reaction. The method has the advantages that: the application range of reaction materials is wide, the catalyst is low in corrosion, high in catalytic activity and recyclable, the product is high in selectivity, and the operating process is simple and high in controllability.

Description

technical field [0001] The invention relates to a method for synthesizing paraformaldehyde by the cyclization reaction of aqueous formaldehyde solution catalyzed by a bifunctional ionic liquid. Background technique [0002] Paraformaldehyde is a white crystal with stable property, low toxicity and easy storage and transportation. It can be used to prepare anhydrous formaldehyde and stabilizer, fumigant, insecticide, molding material, adhesive and disinfectant in color photos. , Antibacterial drugs, etc. At the same time, paraformaldehyde is an important raw material for the synthesis of polyoxymethylene resin. POM has chemical corrosion resistance, high mechanical strength and good plasticity, and is widely used in automobiles, machinery, chemicals, electronics, electrical appliances, instruments and Daily necessities and other fields. With the growth of China's economy, the demand for polyoxymethylene is increasing year by year. The process of synthesizing POM through pa...

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Problems solved by technology

[0003] At present, the sulfuric acid method is generally used in the industry to synthesize paraformaldehyde, which has obvious defects such as strong corrosion of dilute sulfuric acid, high requirements for equipment, large investment, many by-products, and serious environmental pollution.

In recent years, the research on using solid acid instead of protonic acid as catalyst has received great attention. The reported solid acid catalyst system such as ZrO 2 , Zr(OH) 2 、TiO 2 , SnO 2 、Al 2 o 3 (ZSM-20), Y-type zeolite, acidic ion exchange resin, heteropolyacid, etc. 6124480, US 5929257, CN1136812, CN 1162309); Although these catalysts are all effective under certain conditions, one or more defects often exist in the catalytic process, such as harsh operating conditions, longer reaction time and because a large amount of solid supports A large amount of solid waste is generated due to the use of

The above catalyst systems all use more than 60% concentrated formaldehyde as the reaction raw material, which has the disadvantages of low concentration of paraformaldehyde in the synthesis liquid and low product selectivity

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