Method for synthesizing methionine hydroxy analogue by continuous and rapid hydrolysis of 2-hydroxy-4-methylthio butyronitrile

Abstract

The invention provides a method for synthesizing methionine hydroxy analogue by continuous and rapid hydrolysis of 2-hydroxy-4-methylthio butyronitrile. The method comprises the following steps: feeding acid and 2-hydroxy-4-methylthio butyronitrile into a microchannel reactor loading a solid catalyst for reaction, controlling the reaction temperature to be 80 to 130 DEG C and the pressure to be 0.1 to 0.5MPa, ensuring that the residence time of a reactant in a micro channel is 1 to 10min, adding water into the mixed liquid flowing out from the microchannel reactor, continuously hydrolyzing for20 to 60min, and ensuring that the reaction temperature to be 100 to 140DEG C and the reaction pressure to be 0.1 to 0.6MPa to obtain the methionine hydroxy analogue and a small amount of a byproduct, namely ammonium sulfate. By adopting the method, continuous and rapid preparation of the methionine hydroxy analogue is reazlied, the traditional intermittent tower device is avoided, the use of inorganic acid of 50 percent is reduced, no ammonium hydroxide is needed for neutralization, no organic solvent is used, and cleaness, environmental protection and sustainability are achieved; the acidolysis time of 2-hydroxy-4-methylthio butyronitrile is greatly reduced, pyrolysis polymerization of raw materials and production of by-products are reduced, and the product quality and yield are improved.

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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