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A method for reducing the content of crotonaldehyde in the production process of polyvinyl alcohol

A technology of crotonaldehyde and polyvinyl alcohol, which is applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as difficulty in removing crotonaldehyde, and achieve the effect of no pollution and simple process.

Active Publication Date: 2018-03-23
HUNAN XIANGWEI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These methods can better remove acetaldehyde, acetone and other substances in methanol, but it is difficult to remove crotonaldehyde in methanol

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Get the solvent (methanol) sample of polyvinyl alcohol production site, detect with gas chromatography: crotonaldehyde content is 0.146%, then get this sample 100 grams, put into the distillation flask of 150 milliliters, add volume percentage again Take 2.5 grams of 20% sodium hydroxide aqueous solution, place it in a water bath at 65-72 degrees and distill for 30-60 minutes, collect the distillate in a glass bottle, and detect the crotonaldehyde content in the distillate to be 0.002%.

[0022] The results of the experiment showed that the content of crotonaldehyde was 0.146% before the experiment, and the content of crotonaldehyde was 0.002% after purification reaction distillation with sodium hydroxide.

Embodiment 2

[0024] Get the solvent (methanol) sample of polyvinyl alcohol production site, detect with gas chromatography: crotonaldehyde content is 0.13%, then get this sample 100 grams, put into the distillation flask of 150 milliliters, add volume percentage again 1.5 grams of 20% sodium hydroxide aqueous solution was placed in a water bath at 65-72 degrees for distillation for 30-60 minutes, and the distillate was collected in a glass bottle. The content of crotonaldehyde in the distillate was detected to be 0.006%.

[0025] The results of the experiment showed that the content of crotonaldehyde was 0.13% before the test, and the content of crotonaldehyde was 0.006% after purification reaction distillation with sodium oxide.

Embodiment 3

[0027] Take the solvent (methanol) sample at the production site of polyvinyl alcohol, detect with gas chromatography: the content of crotonaldehyde is 0.11%, then take 100 grams of the sample, put it into a 150 ml distillation flask, and then add the volume percentage content of Put 1.5 grams of 20% sodium hydroxide aqueous solution in a water bath at 65-72 degrees to distill for 30-60 minutes, collect the distillate in a glass bottle, and detect the crotonaldehyde content in the distillate to be 0.005%.

[0028] The results of the experiment showed that the content of crotonaldehyde was 0.11% before the experiment, and the content of crotonaldehyde was 0.005% after purification reaction distillation with sodium hydroxide.

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PUM

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Abstract

The invention discloses a method for reducing the content of butenal in a production process of polyvinyl alcohol. According to the method, the content of the butenal which enters a solvent methanol in the production process of the polyvinyl alcohol is reduced through adopting a reaction distillation method under an alkaline condition. The method particularly comprises the following steps: adding a strong alkali solution with the volume percentage concentration of 20% into the methanol containing the butenal; distilling at the temperature of 65 to 70 DEG C until the content of the butenal in the methanol is less than or equal to 0.008%; the adding amount of sodium hydroxide is 0.01% to 0.5% of the weight of the methanol. The method is simple in process and does not generate pollution.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and relates to a method for reducing the content of crotonaldehyde in methanol. Background technique [0002] Polyvinyl alcohol (PVA) is an important water-soluble polymer compound developed in the early 1950s. It is widely used in the production of fibers, and can also be used as chemical fiber fabric slurry, coating, adhesive, emulsifier, papermaking processing aid, etc. [0003] The production process of polyvinyl alcohol (PVA) includes the synthesis of vinyl acetate (VAC), the refining of vinyl acetate (VAC), the polymerization of vinyl acetate (VAC), the alcoholysis of polyvinyl acetate (PVAC) and methanol and The recovery of acetic acid and other five parts, [0004] There are three main chemical reaction processes in the production of polyvinyl alcohol with acetylene and acetic acid as raw materials: [0005] (1) Acetylene reacts with acetic acid to produce vinyl acetate (VAC) ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C31/04C07C29/88C08F116/06
CPCC07C29/88C08F116/06C07C31/04
Inventor 曾卫国周金华肖勤建李自启李泽武田仁主田仁静李少池
Owner HUNAN XIANGWEI
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