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Methacrylic acid decoloration and purification method

A technology of methacrylic acid and purification method, which is applied in the direction of chemical instruments and methods, carboxylate preparation, organic compound preparation, etc. It can solve the problems of high toxicity, high cost, large addition, etc., and achieve high product purity , low production cost and small amount of slag

Active Publication Date: 2014-05-28
齐翔华利新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The decolorization effect of bisulfite and mercaptan is not good, and a large amount needs to be added to achieve the decolorization effect, which will cause secondary pollution. In addition, the addition of mercaptan will trigger the polymerization of methacrylic acid
The decolorization effect of aromatic diamines is average, and they are highly toxic and expensive, so they are not suitable for industrial applications

Method used

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  • Methacrylic acid decoloration and purification method
  • Methacrylic acid decoloration and purification method
  • Methacrylic acid decoloration and purification method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-3

[0023] Embodiment 1-3 (batch distillation):

[0024] The high-temperature reaction gas obtained by gas-phase catalytic oxidation of tert-butanol is cooled and condensed to obtain an aqueous solution of methacrylic acid, and the solid by-product is separated by filtration. Thereafter, use toluene as an extractant to extract methacrylic acid in the aqueous solution, separate the extractant toluene and acetic acid and other light components from the extraction phase by two-step rectification, and obtain the above-mentioned crude methacrylic acid containing a small amount of heavy components at the bottom of the tower. acrylic acid.

[0025] Take 300 grams of the above-mentioned crude methacrylic acid, add 0.9 grams (0.3%) of decolorizer, add 0.15 grams of polymerization inhibitor ZJ-701, mix and enter the methacrylic acid deweighting and decoloring tower for vacuum distillation, and the pressure at the top of the tower is controlled At 4kPaA, the temperature of the tower bottom ...

Embodiment 4-7

[0029] Embodiment 4-7 (batch distillation):

[0030] Carry out rectification under vacuum in the same way as in Example 1, what is changed is the amount of decolorizer p-methoxyaniline relative to the amount of aldehyde and ketone impurities (the multiple of the amount of p-methoxyaniline addition and the total amount of aldehyde and ketone impurities), The content of impurities in methacrylic acid before and after distillation is shown in Table 2. The data in Table 2 shows that the amount of decolorizing agent added is 10 times of the total amount of impurities of aldehydes and ketones, which can achieve better decolorization, and the increase in the amount of raw slag is less than 0.1% of the total amount of raw materials.

[0031] Table 2 The effect of the amount of decolorizing agent p-methoxyaniline on the content of impurities and slag in methacrylic acid

[0032] Unit: ppm

[0033]

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Abstract

The invention belongs to the field of petrochemical engineering and especially discloses a methacrylic acid decoloration and purification method. According to the methacrylic acid decoloration and purification method, a methacrylic acid crude product is used as a raw material. The method comprises the following steps: carrying out catalytic gas phase oxidation on the crude product with tert-butyl alcohol or isobutene to produce a methacrylic acid gas mixture, absorbing, extracting and rectifying. The method is characterized in that a methoxy-bearing or oxethyl-substituted aromatic amine decolorant is added into the crude product and then rectification and purification are carried out; and a methacrylic acid product with chroma being less than 10 can be obtained from the top of a rectifying tower. The method has advantages of simple technology, low production cost, high product purity, small slag-producing amount, stable chroma of methacrylic acid and the like, and is suitable for wide popularization and application.

Description

(1) Technical field [0001] The invention belongs to the field of petrochemical industry, in particular to a method for decolorizing and purifying methacrylic acid. (2) Background technology [0002] Methacrylic acid (MAA) is a very important chemical intermediate, which can be further esterified to produce methyl methacrylate (MMA). MMA is the main monomer raw material for the production of plexiglass. It is used in national defense, aviation, construction, and home decoration. It has a very wide range of applications in the fields of coatings and coatings; methacrylic acid is also a raw material for the preparation of thermoplastic monomers, various spices and pharmaceutical intermediates. Oxidation of tert-butanol (isobutylene) to produce methacrylic acid is an ideal process route in terms of process technology and economy. [0003] In the oxidation process of tert-butanol (or isobutene), in addition to the target product methacrylic acid, certain by-products are also...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/07C07C51/487
CPCC07C51/487C07C57/04
Inventor 陈新建汪青海
Owner 齐翔华利新材料有限公司