Preparation and purification method of methacrylamide

A technology of methacrylamide and purification method, applied in the field of synthesis of methacrylamide, can solve problems such as product loss, waste water environmental pollution, etc., and achieve the effects of improving yield, avoiding pollution, and reducing dissolution

Active Publication Date: 2013-06-12
CHONGQING UNISPLENDOUR CHEM
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  • Abstract
  • Description
  • Claims
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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 methacrylamide
  • Preparation and purification method of methacrylamide
  • Preparation and purification method of methacrylamide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1) Put concentrated sulfuric acid (1360 kg) and acetone cyanohydrin (850 kg) through the rotameter, and put them into the reaction kettle according to the ratio of 1.6:1 (mass ratio), and the acetone cyanohydrin and concentrated sulfuric acid will be hydrolyzed 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;

[0029] 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 135°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 ...

Embodiment 2

[0033] Embodiment 2 (mother liquor circulation applies mechanically 1)

[0034] 1) Put concentrated sulfuric acid (1360 kg) and acetone cyanohydrin (850 kg) through the rotameter, and put them into the reaction kettle according to the ratio of 1.6:1 (mass ratio), and the acetone cyanohydrin and concentrated sulfuric acid will be hydrolyzed 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;

[0035] 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 135°C with steam, because the temperature is too low, the chemical r...

Embodiment 3

[0039] Embodiment 3 (mother liquor circulation applies mechanically 2)

[0040] 1) Put concentrated sulfuric acid (1360 kg) and acetone cyanohydrin (850 kg) through the rotameter, and put them into the reaction kettle according to the ratio of 1.6:1 (mass ratio), and the acetone cyanohydrin and concentrated sulfuric acid will be hydrolyzed 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;

[0041]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 135°C with steam, because the temperature is too low, the chemical re...

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Abstract

The invention discloses a preparation and purification method of methacrylamide. The method comprises the following steps: hydrolyzing and dehydrating by concentrated sulfuric acid to generate methacrylamide sulfate based on acetone cyanohydrin as a main raw material; neutralizing the methacrylamide sulfate by ammonia gas or ammonia water; circularly applying the neutralized centrifuged mother liquor; and purifying the methacrylamide crude product containing ammonium sulfate by sublimating, thereby obtaining the pure methacrylamide. According to the process, the mother liquor can be circularly applied so as to greatly reduce the discharge of salt-containing acid-containing sewage and avoid the environment pollution, reduce the dissolving of the methacrylamide in the mother liquor and improve the yield of the methacrylamide; and the purity of the obtained pure methacrylamide can be more than 99%, and the yield is more than 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 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 (includin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C233/09C07C231/12
Inventor 吴传隆龙晓钦丁永良罗财能张林任星宇何咏梅
Owner CHONGQING UNISPLENDOUR CHEM
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