Preparation method of cheap and high-purity d,l-methionine

A technology of methionine and amino group, applied in the field of preparing D,L-methionine, can solve the problems of high production cost and influence, and achieve the effects of saving production time, reducing production cost and improving production efficiency

Active Publication Date: 2016-03-30
NINGXIA UNISPLENDOUR TIANHUA METHIONINE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But this method is used to produce the 2-hydroxyl-4-methylthiobutyronitrile of 2-amino-4-methylthiobutyronitrile to still adopt traditional method preparation, and its production cost is higher, and quality also needs further improvement, and then affects Yield and cost of final product D,L-methionine

Method used

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  • Preparation method of cheap and high-purity d,l-methionine
  • Preparation method of cheap and high-purity d,l-methionine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] 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%.

[0046] 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

[0048] Pass hydrogen cyanide mixed gas II into 223.3g of 94.5% methional with a mass fraction of 223.3g, 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 0.1%, you can stop feeding the crude hydrocyanic acid mixed gas II, and continue to stir for a period of time, and the conversion rate of 3-methylthiopropionaldehyde is 100%. 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%. The obtained 2-hydroxy-4-methylthiobutyronitrile together with its reaction solution (2-hydroxy-4-methylthiobutyronitrile system) was divided into two parts, one of which was stored at 3°C ​​for 120 days, and no Decomposition; the other part was acidi...

Embodiment 3

[0050] Pass hydrogen cyanide mixed gas II into 223.3g of methional with a mass fraction of 94.5%, 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 0.1%, you can stop feeding the crude hydrocyanic acid mixed gas II, and continue to stir for a period of time, and the conversion rate of 3-methylthiopropionaldehyde is 100%. 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%.

[0051] At 45°C, 416.5g of ammonia water with a mass fraction of 60% was introduced into a stainless steel high-pressure reactor equipped with a stirrer, a thermometer, a pressure gauge, a feed pipe and a heat source. Then, within 2 minutes...

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Abstract

The invention is directed at the field of chemical engineering and provides a cheap preparation method for high purity D,L-methionine. The preparation method comprises the following steps: preparing a hydrocyanic acid gas mixture by using an Andrussow process; fully reacting the hydrocyanic acid gas mixture with methylthiopropionaldehyde under the catalysis of base so as to prepare a 2-hydroxy-4-methylthiobutyronityile system; reacting the 2-hydroxy-4-methylthiobutyronityile system with ammonia under the conditions of heating and pressurization and carrying out pressure reduction and deamination so as to obtain 2-amino-4-methylthiobutyronityile; and subjecting 2-amino-4-methylthiobutyronityile to acidolysis with inorganic acid so as to obtain D,L-methionine. According to the invention, raw materials used in the method are cheap and easily available, the intermediate 2-hydroxy-4-methylthiobutyronityile has stable properties, prepared 2-amino-4-methylthiobutyronityile has high yield and high purity, and D,L-methionine obtained after continued production has the advantages of high yield, high purity, great bulk density and low total production cost.

Description

technical field [0001] The invention aims at the field of chemical industry and relates to a method for preparing D,L-methionine, in particular to a method for preparing D,L-methionine based on the method for preparing 2-amino-4-methylthiobutyronitrile. Background technique [0002] D, L-methionine, also known as methionine, is one of the basic units of protein and the only amino acid containing sulfur among essential amino acids. Its structural formula is as follows: [0003] [0004] D, L-methionine is not only involved in the transfer of methyl groups in animals, the metabolism of phosphorus and the synthesis of epinephrine, choline and creatine, but also the raw material for the synthesis of protein and cystine, so it is widely used in medicine, food and feed And cosmetics and other fields, in which it is used in a large amount as a feed additive. However, due to the limitations of technology and production costs, domestic production cannot meet the demand, and a lar...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C323/58C07C319/20C07C319/28
Inventor 吴传隆秦岭王用贵丁永良朱丽利朱晓莉杨帆
Owner NINGXIA UNISPLENDOUR TIANHUA METHIONINE CO LTD
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