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Method for distillating (methyl) acrylic acid solution

A technology of methacrylic acid and distillation method, applied in azeotropic distillation, chemical instruments and methods, separation/purification of carboxylic acid compounds, etc., can solve the problems such as the effect of preventing polymerization reaction that cannot be completely solved, and achieve the effect of preventing polymerization

Inactive Publication Date: 2006-01-11
NIPPON SHOKUBAI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The preventive effect on the polymerization reaction cannot be completely resolved by the above-mentioned method, and it is desired to distill the above-mentioned (meth)acrylic acid solution that can be polymerized for a long time

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0076] Continuous operation of azeotropic separation of acrylic acid aqueous solution using a distillation column with an inner diameter of 105 mm. The column was loaded with grade 50 stainless steel sieves at 147 mm intervals, with pipes for distillate at the top, pipes for adding reflux liquid, and pipes for adding polymerization inhibitor solution in the middle section, the 26th The first stage is equipped with pipelines for feeding raw material liquid, a container at the bottom, a pipeline for draining bottom liquid and a pipeline for supplying oxygen.

[0077] Carry out the azeotropic separation operation under the following conditions: the raw material liquid is the acrylic acid aqueous solution containing 66.5% by weight of acrylic acid, 30% by weight of water and 2.5% by weight of acetic acid (azeotropic solvent: no more than 1ppm, which is a detectable limit). Produced by the gas-phase catalytic oxidation of propylene (the first catalyst: Co 4 Fe 1 Bi 1 W 2 Mo 10...

Embodiment 2

[0082] The procedure of Example 1 was repeated except that the raw material liquid was added under the condition that the temperature of the added raw material liquid was allowed to be dispersed in the range of 60-80°C (70±10°C).

[0083] The continuous operation was carried out stably for 30 days under the above conditions. After stopping, the interior of the column was inspected and a small amount of polymer was found to be present.

Embodiment 3

[0087] Embodiment 3 (distillation column for separating high boiling point substances)

[0088] Using the same column as that used in Example 1 except that the pipe for feeding the raw material liquid was installed at the bottom of the column, a distillation step for separating high boiling point substances from the acrylic acid solution was carried out.

[0089] The starting liquid is crude acrylic acid containing 97% by weight of acrylic acid, 0.03% by weight of acetic acid, 0.02% by weight of water, 0.5% by weight of maleic acid, 0.001% by weight of toluene and 2.45% by weight of other residues. rate into the distillation column. This crude acrylic acid is obtained by Example 1. In this case, the feed liquid was maintained at a temperature of 75±3°C and then fed to the column. The operating conditions are as follows: the operating pressure is 130 hPa, the bottom temperature is 91° C., the reflux liquid is 13.7 liters / hour, the distillate is 9.1 liters / hour, and the discha...

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Abstract

A method for distilling a raw material liquid containing (meth)acrylic acid substantially free from azeotropic solvents, collected with a collection agent from a mixed gas obtained by gas phase catalytic oxidation reactions which includes feeding to a distillation column the raw material liquid which temperature is substantially equal to that of the entrance place in the column.

Description

technical field [0001] The present invention relates to a process for the distillation of (meth)acrylic acid. Background technique [0002] Acrylic acid is generally produced by subjecting propylene and / or acrolein to a gas-phase catalytic oxidation reaction with a molecular oxygen-containing gas, contacting the resulting acrylic acid-containing gas with water, collecting it as an aqueous solution of acrylic acid, and separating it from the acrylic acid solution and collect acrylic. In the gas containing acrylic acid, by-products such as acetic acid, formic acid, acetaldehyde, formaldehyde or others are contained. Among them, acetic acid is contained in a relatively high amount. In order to produce acrylic acid with high purity, it is necessary to remove acetic acid therefrom. When acetic acid is removed therefrom by distillation, the distillation temperature becomes higher (boiling point of acetic acid: 118.1° C.), so acrylic acid tends to be polymerized. Since acrylic ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C57/04C07C51/44C07C57/07B01D3/36
CPCC07C51/44Y10S203/09Y10S203/22B01D3/36C07C57/04
Inventor 坂元一彦中原整松本行弘真田健次上冈正敏
Owner NIPPON SHOKUBAI CO LTD