Continuous preparation method of 1,4-butanediol

Abstract

The invention discloses a continuous preparation method of 1,4-butanediol. The method comprises the following steps: carrying out a monoesterification reaction on bio-based succinic acid and methanolto obtain a succinic acid monoesterification liquid containing succinic acid monomethyl ester; mixing with monomethyl maleate to obtain a mixed esterification liquid; feeding into a double esterification reaction tower, and carrying out a double esterification reaction to generate a mixture of dimethyl succinate and dimethyl maleate; feeding the mixture into a hydrogenation reactor, and carrying out a hydrogenation reaction, wherein the the dimethyl maleate in the mixture is hydrogenated to generate dimethyl succinate; and performing a cascade reaction to convert into an intermediate product gamma-butyrolactone, and then generating 1,4-butanediol and tetrahydrofuran. According to the method, the bio-based succinic acid is adopted to partially replace monomethyl maleate to produce 1,4-butanediol, so that the consumption of petroleum chemicals is reduced, and the production cost of 1, 4-butanediol is reduced; and bio-based succinic acid and methanol are subjected to a monoesterificationreaction, and then mixing is performed with monomethyl maleate, so that the mutual influence caused by co-monoesterification of succinic acid and maleic anhydride is avoided.

Description

technical field [0001] The invention belongs to the field of chemical synthesis and relates to a continuous preparation method of 1,4-butanediol. Background technique [0002] 1,4-Butanediol (BDO) is an important basic organic chemical raw material, mainly used in the production of tetrahydrofuran (THF), polybutylene terephthalate (PBT), γ-butyrolactone and polyurethane ( PU). At present, the more advanced BDO production process in the world is the Huntsman / Davy n-butane-maleic anhydride combined process route. More than 25% of the production capacity comes from the maleic anhydride method, and this method is often used in new plants. The method is that butane is oxidized to generate maleic anhydride, maleic anhydride undergoes monoesterification first to generate monomethyl maleate, and monomethyl maleate undergoes double esterification in the esterification tower to generate dimethyl maleate , Dimethyl ester is hydrogenated and catalyzed to produce BDO and other by-produ...

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Problems solved by technology

[0005] In order to overcome the shortcomings of the Huntsman / Davy n-butane-maleic anhydride joint process route, the raw materials involved in the production come from fossil raw materials, which have serious environmental pollution and high environmental protection pressure; Under the concentration of methanol, the co-monoesterification of succinic acid and maleic anhydride produced by the biological fermentation method will affect each other, resulting in a difference in reaction rate between the two, affecting the production of monomethyl maleate through the monoesterification of maleic anhydride, resulting in the production process. fluctuation

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