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Preparation and purification method of clean methacrylamide

A technology of methacrylamide and purification method, which is applied in the field of synthesis of methacrylamide, can solve the problems of waste water environmental pollution, product loss, etc., and achieve the effects of avoiding pollution, increasing yield, and reducing emissions

Inactive Publication Date: 2013-06-05
CHONGQING UNISPLENDOUR CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The production of methacrylamide (including methyl methacrylate and methacrylic acid) in the past process route will produce a large amount of wastewater. Since the wastewater contains a certain amount of methacrylamide and methacrylic acid, as the wastewater is stored for a long time, A large amount of polymers are produced in wastewater, and the discharge of wastewater pollutes the environment and is a loss to the product

Method used

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  • Preparation and purification method of clean methacrylamide
  • Preparation and purification method of clean methacrylamide
  • Preparation and purification method of clean methacrylamide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] 1) Put concentrated sulfuric acid (1360 kg) and acetone cyanohydrin (850 kg) into the reactor at a ratio of 1.6:1 (mass ratio) through a rotameter, and hydrolyze the acetone cyanohydrin with concentrated sulfuric acid to form α-formamide Because the reaction is exothermic at this time, the cooling system is turned on to keep the reaction temperature in the pot at 90°C, and the product overflows from the overflow of the reactor and enters the tubular reactor;

[0030] 2) The above-mentioned reactants continue to chemically react with concentrated sulfuric acid in the tubular reactor. Under the action of concentrated sulfuric acid, α-formamidoisopropyl hydrogensulfate is dehydrated to form methacrylamide sulfate. This reaction is endothermic The reaction is heated to 130°C with steam. Because the temperature is too low, the chemical reaction is incomplete, and the temperature is too high, which is easy to cause polymerization or carbonization, so temperature control is a key ...

Embodiment 2

[0034] Example 2 (Mother liquor circulation is applied 1)

[0035] 1) Put concentrated sulfuric acid (1360 kg) and acetone cyanohydrin (850 kg) into the reactor at a ratio of 1.6:1 (mass ratio) through a rotameter, and hydrolyze the acetone cyanohydrin with concentrated sulfuric acid to form α-formamide Because the reaction is exothermic at this time, the cooling system is turned on to keep the reaction temperature in the pot at 95°C, and the product overflows from the overflow of the reactor and enters the tubular reactor;

[0036] 2) The above-mentioned reactants continue to chemically react with concentrated sulfuric acid in the tubular reactor. Under the action of concentrated sulfuric acid, α-formamidoisopropyl hydrogensulfate is dehydrated to form methacrylamide sulfate. This reaction is endothermic The reaction is heated to 135°C with steam. Because the temperature is too low, the chemical reaction is incomplete, and the temperature is too high, which is easy to cause polym...

Embodiment 3

[0040] Example 3 (Mother liquor circulation application 2)

[0041] 1) Put concentrated sulfuric acid (1360 kg) and acetone cyanohydrin (850 kg) into the reactor at a ratio of 1.6:1 (mass ratio) through a rotameter, and hydrolyze the acetone cyanohydrin with concentrated sulfuric acid to form α-formamide Because the reaction is exothermic at this time, the cooling system is turned on to keep the reaction temperature in the pot at 90°C, and the product overflows from the overflow of the reactor and enters the tubular reactor;

[0042] 2) The above-mentioned reactants continue to chemically react with concentrated sulfuric acid in the tubular reactor. Under the action of concentrated sulfuric acid, α-formamidoisopropyl hydrogensulfate is dehydrated to form methacrylamide sulfate. This reaction is endothermic The reaction is heated to 130°C with steam. Because the temperature is too low, the chemical reaction is incomplete, and the temperature is too high, which is easy to cause poly...

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Abstract

The invention discloses a preparation and purification method of clean methacrylamide. The preparation and purification method disclosed by the invention comprises the following steps: taking acetone cyanohydrin as a main raw material, generating methacrylamide sulfate by hydrolysis with concentrated sulfuric acid, dehydration and other actions, neutralizing the methacrylamide sulfate with ammonia or ammonia water, then supplementing a certain amount of water to dissolve generated ammonium sulfate, getting a methacrylamide semi-finished product, indiscriminately using part of mother liquor after neutralization in a circulating manner, and performing re-crystallization and purification on the methacrylamide semi-finished product to get a methacrylamide pure product, wherein the recrystallization mother liquor can also be indiscriminately used in the circulating manner. According to the preparation and purification method disclosed by the invention, a new process route is adopted, and the mother liquor can be used indiscriminately in the circulating manner, so that the emission of wastewater containing salts and acids is greatly reduced, the environmental pollution caused by the wastewater is avoided, the dissolution of the methacrylamide in the mother liquor is further reduced, the yield of the methacrylamide is improved, the methacrylamide with the content of above 98.5% is obtained, the content of the ammonium sulfate is within 1.5%, and the yield is above 90%.

Description

technical field [0001] The invention relates to the technical field of synthesis of methacrylamide, in particular to a method for preparing and purifying clean methacrylamide. Background technique [0002] Methacrylic acid amine is mainly used as silk weighting agent, fiber leveling agent, hygroscopic agent, adhesive and antistatic agent, and also used as cement additive, mortar additive, artificial leather additive, etc. The quality of methacrylamide depends on the weight gain rate of methacrylamide in the process of silk weight gain. The preparation of methacrylamide includes methacrylonitrile hydrolysis method, acetone cyanohydrin acid hydrolysis method, methyl methacrylate ammonia solution and synthesis of methacrylic acid and ammonia. The industry mainly adopts the hydrolysis method of acetone cyanohydrin, which is still in the small test stage in China. The product purity reaches 95%, and the yield is often only about 60% to 70%. The production of methacrylamide (in...

Claims

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Application Information

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IPC IPC(8): C07C233/09C07C231/12C07C231/24
Inventor 吴传隆丁永良龙晓钦罗财能
Owner CHONGQING UNISPLENDOUR CHEM
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