Process method for synthesizing sec-butyl acetate from C4 fractions

Abstract

The invention relates to a process method for synthesizing sec-butyl acetate from C4 fractions. The process method is characterized in that acetic acid and C4 fractions are used as raw materials, macroporous strongly-acidic cation exchange resin is used as a catalyst, a 3-5-segment tubular fixed-bed reactor is employed, the acetic acid is fed in only one step, the C4 fractions are fed segment by segment, and the molar ratio of acetic acid to olefin in each segment of the reactor is greater than 9 when the total molar ratio of acetic acid to olefin in the reaction is 2-3; and an olefin polymerization inhibitor is simultaneously added to the reaction system at the adding amount of 20-200 mu g / g, and reaction is carried out at the reaction temperature of 50-120 DEG C and the reaction pressure of 1.0-2.0 MPa to generate sec-butyl acetate. The method has the advantages and effects that the selectivity of sec-butyl acetate is improved, the catalyst can be recycled and has long life, and the product has good quality.

Description

technical field [0001] The invention relates to a process for synthesizing sec-butyl acetate by fractionation of C4, which belongs to the field of organic chemical industry. Background technique [0002] Second-butyl acetate is a good organic solvent, which is widely used in nitrocellulose, paint, artificial leather, medicine, ink and plastic industries. The traditional method of producing sec-butyl acetate both at home and abroad is to adopt the batch-type tank reaction, and use sulfuric acid as a catalyst to catalyze the reaction of acetic acid and butanol. Because water is produced simultaneously in the esterification process of acetic acid and butanol, and water will not only cause the ester hydrolysis reaction of the reverse reaction of the esterification reaction, but also cause separation difficulties due to the azeotropy of water and acetic acid, so the current research mainly focuses on acetic acid and acetic acid. On the direct esterification of butene, as US60180...

AI Technical Summary

Problems solved by technology

For the production of sec-butyl acetate, Chinese patent CN10112656A has proposed the method that modified resin catalyst synthesizes sec-butyl acetate under the condition of acid-ene ratio 1: 1.15-1.80, because olefin esterification reaction takes place under acidic catalyst catalysis , the polymerization reaction also occurs to produce by-products such as C8, C12 and C16. The selectivity of sec-butyl acetate is up to 98%, which not only reduces the yield of sec-butyl acetate, but also affects product quality

And Chinese patent CN101143819A has reported the method that adopts catalytic distillation process to synthesize sec-butyl acetate with C4 raw material, although sec-butyl acetate selectivity can reach 99%, but does not contain 1,3-butadiene in the C4 raw material that it adopts, However, the 1,3-butadiene content in the C4 fraction of oil refineries is relatively high. If the process requirements are met, the selective hydrogenation process of precious metal catalysts must be adopted, which not only has a complicated process flow, but also has high operating costs.

[0003] At present, the main source of C4 fraction is the catalytic cracking unit of the refinery. With the development trend of heavy and inferior crude oil, the catalytic cracking unit must increase the operating severity of the catalytic cracking unit in order to increase the yield of light oil products. The 1,3-butadiene content contained in the refinery C4 fraction is getting higher and higher, and the refinery C4 fraction with a high 1,3-butadiene content is used as a raw material to synthesize sec-butyl acetate, no matter what kind of solid acidic catalyst is used , 1,3-butadiene itself will undergo polymerization reaction to form colloid covering the active center of the catalyst, reducing the catalyst life; due to the high reactivity of 1,3-butadiene, self-polymerization also interacts with other C4 raw materials The C4 fraction reacts to produce C8, C12 and C16 or even higher molecular weight polymers, thereby reducing the selectivity of the C4 fraction to produce sec-butyl acetate and affecting product quality

Have not yet seen the report about reducing 1,3-butadiene to the synthetic reaction solution of sec-butyl acetate

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