A method for continuously and rapidly hydrolyzing 2-hydroxy-4-methylthiobutyronitrile to synthesize methionine hydroxyl analogs

Abstract

The invention provides a method for continuously and rapidly hydrolyzing 2-hydroxy-4-methylthiobutyronitrile to synthesize methionine hydroxyl analogs. The acid and 2-hydroxy-4-methylthiobutyronitrile are fed into a solid catalyst The reaction is carried out in the microchannel reactor, the reaction temperature is controlled at 80-130°C, the pressure is 0.1-0.5MPa, the residence time of the reactant in the microchannel is 1-10min, and the mixed liquid flowing out of the microchannel reactor is added with water to continue Hydrolyze for 20-60 minutes, the reaction temperature is 100-140°C, and the reaction pressure is 0.1-0.6MPa to obtain the methionine hydroxyl analog, and a small amount of ammonium sulfate is produced as a by-product. The present invention realizes the rapid and continuous preparation of methionine hydroxyl analogs, avoids the traditional intermittent tower kettle device, reduces the use of inorganic acids by 50%, does not need to be neutralized with ammonia water, does not use organic solvents, is clean, environmentally friendly and sustainable; and greatly shortens the 2 The acid hydrolysis time of hydroxy-4-methylthiobutyronitrile reduces the pyrolysis polymerization of raw materials and the generation of by-products, and improves product quality and yield.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a method for continuously and rapidly hydrolyzing 2-hydroxy-4-methylthiobutyronitrile to synthesize methionine hydroxyl analogs. Background technique [0002] Methionine Hydroxy Analogue (MHA) is a highly acidic liquid organic acid containing 12% water and 88% active methionine hydroxy analogue (including at least 65% 2-hydroxy-4-methionine Thiobutyric acid monomer, and 2-hydroxy-4-methylthiobutyric acid dimer and multimer with a content not exceeding 23%). In poultry feeding, methionine hydroxy analogues exhibit properties similar to those of amino acids known to act as growth stimulators and thus become important additives for animal feed. [0003] The main synthesis method of methionine hydroxyl analogs is cyanohydrin hydrolysis (such as patents CN1067983C, CN1069311C, CN105130861A, US2745745A, US3175000A, US4524077, US4912257, US5847207 and US5856567), which is to react meth...

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Problems solved by technology

[0007] In view of the above-mentioned shortcoming of prior art, the object of the present invention is to provide a kind of method for the synthesis of methionine hydroxyl analog of continuous rapid hydrolysis 2-hydroxyl-4-methylthiobutyronitrile, for solving the problem of synthesizing methionine hydroxyl in the prior art. A large amount of sulfuric acid is excessive during analogue, and follow-up consumes a large amount of ammonia, and reaction time is too long, and reaction rate is slower, and hydration and hydrolysis reaction are not easy to complete, easily cause raw material decomposition, 2-hydroxyl-4-methylthiobutyronitrile pyrolysis polymerization and The formation of its by-products can easily lead to problems such as the darker color of the final product methionine hydroxyl analogs

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