Method for absorbing and refining high-purity methylacrolein

Abstract

The invention belongs to the field of fine chemical engineering, and relates to a method for absorbing and refining high-purity methylacrolein. According to the method, phenoxyethanol, diethylene glycol monophenyl ether or a mixture of the phenoxyethanol and the diethylene glycol monophenyl ether is adopted as an absorbent to absorb the methylacrolein in the mixed gas in the oxidation step, and the methylacrolein with the purity larger than 99% is obtained through standing layering and rectification. The process has the advantages of high absorption efficiency, high product purity, simple and non-toxic absorbent recovery and application, high safety, simple operation and less absorbent loss, and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of fine chemicals, and in particular relates to a method for absorbing and refining high-purity methacrolein. Background technique [0002] Methacrolein is an important chemical raw material. Further oxidation can obtain methacrylic acid, and derivatives such as methyl methacrylate and glycidyl methacrylate; after reduction of methacrolein, methacrylic acid can be obtained Propanol, which is an important raw material for a new generation of high-performance water reducers; in addition, methacrolein can also be used in the manufacture of copolymers and resins. [0003] At present, the method for producing methacrolein is mainly the selective oxidation of isobutylene or tert-butanol, which is environmentally friendly. However, the product obtained by this method is in a gaseous state, which contains a large amount of diluent gas (such as nitrogen, etc.), and the content of methacrolein is relatively low, so it needs to...

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Problems solved by technology

[0004] Patent CN 1817844A uses water as an absorbent to absorb methacrolein, but due to poor mutual solubility between water and methacrolein, a large amount of water is needed for absorption, the absorption efficiency is low, and energy consumption is large

[0005] The patent GP2110031 uses methanol as the absorbent to improve the absorption efficiency, but the boiling point of methanol is too low, and it is easy to vaporize during the absorption process, causing a large amount of methanol to be discharged with the tail gas, resulting in a large loss of methanol and easy to cause safety accidents

[0006] The patent US3957880 uses ethanol and isopropanol as absorbents. Although these absorbents have a higher boiling point than methanol, the existence of a large amount of diluent gas in the oxidation reaction will still cause the absorbent to be taken away, causing losses. The miscibility is good, and the water in the reaction product will also be absorbed, causing separation difficulties

[0007] Patent CN101844973A adopts alcohols with carbon number greater than 4 as absorbent, which reduces the loss of absorbent to a certain extent, but alcohols with larger carbon number basically have a stronger pungent smell (such as butanol has a pungent odor). Odor, can cause coughing), leading to serious air pollution after the exhaust gas is discharged after absorption, and some alcohols have a low flash point, which is unsafe to use

[0008] CN103833537A uses alkanes with 6 to 8 carbons as absorbents, but the boiling points of these alkanes are less different from those of methacrolein, so separation is difficult, and the lower boiling point will also cause more absorbent loss

[0009] Patent CN101020625 uses ionic liquids for absorption, which has high absorption efficiency, but ionic liquids are expensive and difficult to use on a large scale

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