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Method for using crude hydrocyanic acid gas for preparing 2-hydroxy-4-methylmercapto-butyronitrile

A technology for the preparation of methylthiobutyronitrile and gas, which is applied in the field of chemical industry, can solve the problems of purification and downstream production troubles, cost increase, economic loss, etc., and achieve the effects of saving production time, improving production efficiency, and simple equipment

Inactive Publication Date: 2013-12-04
CHONGQING UNISPLENDOUR CHEM
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0008] Obviously, in these bibliographical reports, no matter which way is adopted to synthesize 2-hydroxyl-4-methylthiobutyronitrile, in order to obtain high yield, purer hydrocyanic acid is needed, and hydrocyanic acid is often excessive, hydrogen Additional distillation purification and excessive use of cyanic acid will result in an increase in costs, which, especially on an industrial scale, will lead to huge economic losses
Furthermore, as the method disclosed in US2745745, under the use of inappropriate catalyst, the formation of by-products in the cyanidation process may be caused, which will cause troubles for subsequent purification and downstream production

Method used

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  • Method for using crude hydrocyanic acid gas for preparing 2-hydroxy-4-methylmercapto-butyronitrile

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] The hydrocyanic acid mixed gas I from the hydrocyanic acid synthesis tower was detected. The composition of the hydrocyanic acid mixed gas I was: 8.87% hydrocyanic acid gas, 3.88% water vapor, 1.64% ammonia gas, 1.13% hydrogen gas, nitrogen gas 76.01%, oxygen 1.48%, carbon monoxide 5.67%, carbon dioxide 1.13%, methane 0.39%.

[0047] Hydrocyanic acid mixed gas I passes through a 75% sulfuric acid tower to absorb ammonia and water vapor in the mixed gas, and the composition of the obtained hydrocyanic acid mixed gas II is: 9.35% hydrocyanic acid gas, 1.57% hydrogen gas, and 79.44% nitrogen gas %, oxygen 1.71%, carbon monoxide 5.79%, carbon dioxide 1.50%, methane 0.64%.

Embodiment 2

[0049] Pass hydrogen cyanide mixed gas II into 223.3g of 94.5% methional, which contains 3.3g of pyridine. React under normal pressure, control the reaction temperature to 45°C, the ventilation rate to 300L / min, absorb the tail gas with sodium hydroxide, and monitor the residual amount of methionaldehyde by HPLC. When the residual amount of methionaldehyde is less than 0.5%, it is the end of the reaction, and the feeding can be stopped. A total of 270.64 g of light yellow liquid was obtained, the content of 2-hydroxy-4-methylthiobutyronitrile was 98%, and the residual hydrocyanic acid was 0.5%. Divide the obtained 2-hydroxy-4-methylthiobutyronitrile together with the reaction solution (that is, the 2-hydroxy-4-methylthiobutyronitrile reaction system) into two parts. Add 8.5g of water to one of them, store it at 3°C ​​for 120 days, no decomposition is seen; add 8.5g of water to the other, then acidify it to pH 3 with 85% sulfuric acid, and store it at 20°C After storage for 1...

Embodiment 3

[0051] Pass hydrogen cyanide mixed gas II into 223.3g of 94.5% methional, which contains 2.2g of pyridine and 10g of water. Under 0.15MPa, the reaction temperature is controlled to be 42°C, the ventilation rate is 280L / min, the tail gas is absorbed with sodium hydroxide, and the residual amount of methional is monitored by HPLC. When the residual amount of methionaldehyde is less than 0.5%, it is the end of the reaction, and the feeding can be stopped. A total of 279.54 g of light yellow liquid was obtained, the content of 2-hydroxy-4-methylthiobutyronitrile was 98%, and the residual hydrocyanic acid was 0.07%. The obtained 2-hydroxy-4-methylthiobutyronitrile was equally divided into two together with the reaction solution. One of them was stored at 3°C ​​for 120 days without decomposition; the other was acidified with 85% sulfuric acid to pH 3 and stored at 20°C for 130 days, 2-hydroxy-4-methylthiobutyl Nitrile decomposition rate was 0.3%.

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Abstract

The invention aims at the chemical engineering field, and relates to a method for using crude hydrocyanic acid gas for preparing 2-hydroxy-4-methylmercapto-butyronitrile. Based on the Andrussow method composition principle, the method takes methane, ammonia gas and oxygen gas as raw material to obtain hydrocyanic acid mixed gas I through preparation; the hydrocyanic acid mixed gas I is subjected to deamination treatment to obtain hydrocyanic acid mixed gas II; under the alkaline catalytic action, the hydrocyanic acid mixed gas II is fully reacted with methylmercapto-propionaldehyde to obtain the 2-hydroxy-4-methylmercapto-butyronitrile. The raw material without rectification and purification is adopted for the method and is low in price and easy to get, and the prepared 2-hydroxy-4-methylmercapto-butyronitrile is high in yield and purity. Moreover, an obtained 2-hydroxy-4-methylmercapto-butyronitrilereaction system not purified and separated is stable in property, capable of being stored for a long time and convenient to use in production of down-stream products.

Description

technical field [0001] The invention aims at the field of chemical industry and relates to a method for preparing 2-hydroxy-4-methylthiobutyronitrile by using crude hydrocyanic acid gas. Background technique [0002] 2-Hydroxy-4-methylthiobutyronitrile is an important intermediate in the production of D,L-methionine or 2-hydroxy-4-methylthiobutyric acid. The yield and cost of 2-hydroxy-4-methylthiobutyronitrile have an important impact on the quality and cost of the final produced D,L-methionine or 2-hydroxy-4-methylthiobutyric acid. [0003] In theory, the preparation of 2-hydroxy-4-methylthiobutyronitrile is known, mainly including the following two ways: [0004] (1) Methylthiopropionaldehyde is prepared by reacting with hydrocyanic acid under the catalysis of alkali; [0005] (2) Methylthiopropionaldehyde is prepared by reacting with alkali metal cyanide under the action of sodium bisulfite. [0006] The method disclosed in US5756803 is a specific method for preparing...

Claims

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Application Information

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IPC IPC(8): C07C323/60C07C319/20
CPCC07C319/20C07C323/60C07D233/76
Inventor 吴传隆秦岭杨帆任星宇丁永良朱丽利陈宏杨王用贵李欧
Owner CHONGQING UNISPLENDOUR CHEM
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