Method for joint production of methacrylamide, methyl methacrylate and methacrylic acid

A technology of methyl methacrylate and methacrylamide, applied in the field of methacrylamide, which can solve the problems of difficulty in recycling ammonium sulfate, product loss, and environmental pollution caused by waste liquid discharge, so as to reduce emissions and increase productivity , Environmentally friendly effect

Active Publication Date: 2013-08-21
CHONGQING UNISPLENDOUR CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The production of methacrylamide (including methyl methacrylate and methacrylic acid) in the past process will produce a large amount of waste water. Since the waste water contains a certain amount of methacrylamide and methacrylic acid, as the waste water is stored for a long time, the waste water A large number of polymers are produced in the process, which brings great difficulties to the recovery and treatment of ammonium sulfate. The discharge of waste liquid pollutes the environment and is also a loss to the product.

Method used

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  • Method for joint production of methacrylamide, methyl methacrylate and methacrylic acid

Examples

Experimental program
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Embodiment 1

[0029] 1) Put concentrated sulfuric acid (1368 kg) and acetone cyanohydrin (850 kg) through the rotameter and put them into the reaction kettle at a ratio of 1.6:1 (mass ratio). Acetone cyanohydrin reacts with concentrated sulfuric acid and hydrolyzes to form α-formamide Base isopropyl hydrosulfate, because the reaction at this time is an exothermic reaction, so 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 reactants continue to react with concentrated sulfuric acid in the tubular reactor, and α-formamidoisopropyl hydrogen sulfate is dehydrated under the action of concentrated sulfuric acid to form methacrylamide sulfate. This reaction is endothermic Reaction, heated to 130°C with steam, because the temperature is too low, the chemical reaction is incomplete, and the temperature is too high, it is easy to cause polymerization or...

Embodiment 2

[0039] 1) Put concentrated sulfuric acid (1368 kg) and acetone cyanohydrin (850 kg) through the rotameter and put them into the reaction kettle at a ratio of 1.6:1 (mass ratio). Acetone cyanohydrin reacts with concentrated sulfuric acid and hydrolyzes to form α-formamide Base isopropyl hydrosulfate, because the reaction at this time is an exothermic reaction, so 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;

[0040] 2) The above reactants continue to react with concentrated sulfuric acid in the tubular reactor, and α-formamidoisopropyl hydrogen sulfate is dehydrated under the action of concentrated sulfuric acid to form methacrylamide sulfate. This reaction is endothermic Reaction, heated to 130°C with steam, because the temperature is too low, the chemical reaction is incomplete, and the temperature is too high, it is easy to cause polymerization or...

Embodiment 3

[0049] 1) Put concentrated sulfuric acid (1368 kg) and acetone cyanohydrin (850 kg) through the rotameter and put them into the reaction kettle at a ratio of 1.6:1 (mass ratio). Acetone cyanohydrin reacts with concentrated sulfuric acid and hydrolyzes to form α-formamide Base isopropyl hydrosulfate, because the reaction at this time is an exothermic reaction, so 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;

[0050] 2) The above reactants continue to react with concentrated sulfuric acid in the tubular reactor, and α-formamidoisopropyl hydrogen sulfate is dehydrated under the action of concentrated sulfuric acid to form methacrylamide sulfate. This reaction is endothermic Reaction, heated to 130°C with steam, because the temperature is too low, the chemical reaction is incomplete, and the temperature is too high, it is easy to cause polymerization or...

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Abstract

The invention discloses a method for joint production of methacrylamide, methyl methacrylate and methacrylic acid. Methacrylamide sulfate is prepared from acetone cyanohydrin which is taken as a major raw material through concentrated sulfuric acid hydrolysis, dehydration and other effects; the methacrylamide sulfate is neutralized through ammonia gas or ammonia water, and at least one part of neutralized mother liquor circulates to an esterification step of producing methyl methacrylate and a hydrolysis step of producing methacrylic acid, so as to produce methyl methacrylate and methacrylic acid. The joint production method can realize the complete reuse of the methacrylamide in the mother liquor and convert the methacrylamide into the methyl methacrylate and the methacrylic acid, so as to reduce the loss of the methacrylamide, improve the yields of the methyl methacrylate and the methacrylic acid, and reduce the discharge of wastewater; and besides, the neutralized mother liquor can be extracted to avoid the accumulation of impurities in a process of purifying the methacrylamide.

Description

technical field [0001] The invention relates to a joint production method of methacrylamide, methyl methacrylate and methacrylic acid. Background technique [0002] Methyl methacrylate is a monomer for the production of plexiglass, and it is one of the few macromolecular monomers produced in large tonnages in the world. At present, the practical production process route of methyl methacrylate is the acetone cyanohydrin method, which is obtained by adding acetone and hydrogen cyanide to acetone cyanohydrin, and then undergoes amidation and methylation to obtain monomeric methyl methacrylate. [0003] 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. At present, methacrylamide also adopts the acetone cyanohydrin method, that is, sulfuric acid and acetone cyanohydrin are put into the reactor for amidation reac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C233/09C07C231/12C07C69/54C07C67/20C07C57/04C07C51/06C01C1/24
Inventor 吴传隆丁永良郑道敏姚如杰陈宏杨王贵王用贵
Owner CHONGQING UNISPLENDOUR CHEM
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