Synthesis technique of alpha-cyanoacrylate monomer

Abstract

The invention belongs to the field of adhesives, and particularly relates to a synthesis technique of an alpha-cyanoacrylate monomer, which comprises the following steps: (1) directly reacting cyanoacetate and polyformaldehyde, which are used as raw materials, under solventless conditions by using a basic catalyst; (2) naturally cooling, keeping the temperature, and dehydrating to obtain the crude product; and (3) in the presence of a polymerization inhibitor, preparing the alpha-cyanoacrylate monomer, wherein the basic catalyst in the step (1) is one or mixture of hexahydropyridine, pyridine and KOH, the cyanoacetate is one or mixture of methyl cyanoacetate, ethyl cyanoacetate and n-butyl cyanoacetate, the polymerization inhibitor in the step (3) is hydroquinone and sulfur dioxide, a dehydrating agent is used for dehydration in the step (2); and the dehydrating agent is one or mixture of benzene, methylbenzene and methanol. The reaction process has the advantages of no need of organic solvent, low energy consumption, obvious environmental protection effect and high target product yield.

Description

Technical field [0001] The invention belongs to the field of adhesives, and particularly relates to a synthesis process of α-cyanoacrylate monomers. Background technique [0002] Alpha-cyanoacrylate adhesives are an attractive type of structural adhesives. It was accidentally discovered by Eastman Company of the United States in 1955 when synthesizing ethylene compounds. In 1959, Eastman·Kodak Company of the United States began production and marketing. Because of its high chemical activity, it can cure and bond in a very short time, even a few seconds. [0003] The most common α-cyanoacrylate glue is α-ethyl cyanoacrylate glue (commonly known as 502 glue), which is a unique one-component fast-curing adhesive, also known as "instant dry glue", "instant dry glue" "Super glue", etc., which have a solidified block, a wide range of bonding materials, low viscosity, thin glue layer, transparency, oil resistance and electrical insulation, strong penetration, and convenient use. Soon ...

AI Technical Summary

Problems solved by technology

[0005] Through a large number of production practices, it is found that the above-mentioned method has the following defects: 1. The synthetic method of ethyl cyanoacetate and formaldehyde solution has a long production cycle, and it is necessary to use complex operations such as a large amount of solvent dehydration after drying the polymer produced by the synthesis.

[0006] 2. The method of synthesizing ethyl cyanoacetate and paraformaldehyde in the presence of an organic solvent needs to raise the temperature of cyanoacetate, paraformaldehyde and solvent together. The amount of solvent used is large, the energy consumption is large, and it is not environmentally friendly.