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Preparation of biformyl by oxidizing acetaldehyde

A technology of glyoxal and acetaldehyde, applied in the field of chemical technology, can solve problems such as strong corrosion and environmental pollution, and achieve the effect of simple equipment, improved technical level, and high market competitiveness.

Inactive Publication Date: 2009-07-08
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, concentrated nitric acid and concentrated sulfuric acid are highly corrosive, and the NO, NO 2 and SO 2 will pollute the environment

Method used

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  • Preparation of biformyl by oxidizing acetaldehyde
  • Preparation of biformyl by oxidizing acetaldehyde

Examples

Experimental program
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Effect test

Embodiment 1

[0026] 12.6g selenium dioxide (commercially available) is dissolved in water, is made into weight percent concentration and is 20% selenous acid solution; Adding weight percent concentration is 10g of acetaldehyde solution 10g of weight percent concentration in reactor R1, stirs, drops Add selenous acid solution, react at 65°C for 4 hours, selenium dioxide selectively oxidizes acetaldehyde to generate glyoxal product, and undergo solid-liquid separation to obtain liquid phase product solution and solid elemental selenium respectively, and analyze the liquid phase product components , the yield of glyoxal was 85.86%, and the selectivity was 86.15%.

Embodiment 2

[0028] Add the elemental selenium obtained in Example 1 into the reactor R2, add water, fully stir, then dropwise add a hydrogen peroxide solution with a concentration of 30% by weight, oxidize the elemental selenium into selenium dioxide, and generate an aqueous solution of selenium dioxide, i.e. selenic acid solution. Under the condition that the molar ratio of hydrogen peroxide and selenium is 1:1 and 25°C, the reaction is carried out for 4 hours, and the yield of selenous acid is 88.65%.

Embodiment 3

[0030] The selenous acid solution obtained in Example 2 was returned to reactor R1 to prepare glyoxal by oxidizing acetaldehyde. The conditions were the same as in Example 1, and the yield of glyoxal was 84.92%, and the selectivity was 86.03%.

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Abstract

The invention relates to a method for preparing glyoxal by oxidizing acetaldehyde, which is characterized in that selenium dioxide is used to prepare selenous acid aqueous solution taken as oxidant; glyoxal is formed by using the selenium dioxide to selectively oxidize acetaldehyde; meanwhile, the selenium dioxide is reduced into simple-substance selenium separated out; reaction products are separated to generate a glyoxal solution and simple-substance selenium; the simple-substance selenium separated out by use of hydrogen peroxide is the selenium dioxide; selenous acid solution is formed, returned and used for oxidizing acetaldehyde so as to prepare glyoxal. Or commercially available solid selenium is taken as raw material; selenium dioxide is first prepared by using hydrogen peroxide to oxidize simple-substance selenium; glyoxal is prepared by utilizing the prepared selenous acid solution to oxidize acetaldehyde; and then selenium is cyclically used. Under optimum conditions, the yield and selectivity of glyoxal and the yield of selenous acid are all more than 85 percent. The method for preparing glyoxal has the advantages of mild reaction conditions, high selectivity and high yield, cyclically uses selenium in a system, and has broad industrial application prospects.

Description

Technical field: [0001] The invention relates to a method for preparing glyoxal by oxidizing acetaldehyde, in particular to a method combining two processes of preparing glyoxal by oxidizing acetaldehyde with selenium dioxide and preparing selenium dioxide by oxidizing elemental selenium with hydrogen peroxide. The invention belongs to the technical field of chemical technology in the chemical industry. Background technique [0002] Glyoxal is an aliphatic dialdehyde with the simplest molecular structure. In addition to the generality of aliphatic aldehydes, it also has some special chemical properties. It is an important chemical raw material and intermediate, widely used in textiles, medicine, Metallurgy, environmental protection and other fields. Glyoxal is mainly produced in industry by air oxidation of ethylene glycol and nitric acid oxidation of acetaldehyde. Among them, the ethylene glycol air oxidation process is simple and the product yield is high, but the cost o...

Claims

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Application Information

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IPC IPC(8): C07C47/127C07C45/28
Inventor 崔群朱鸭梅王海燕蒋亚明
Owner NANJING UNIV OF TECH
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