Refining method for glyoxalic acid

A refining method and glyoxylic acid technology are applied in the preparation of carboxylate, chemical instruments and methods, preparation of organic compounds, etc., can solve problems such as poor quality of glyoxylic acid products, achieve low production cost, improve product quality, The effect of promoting development and production

Inactive Publication Date: 2012-11-21
HUBEI HONGYUAN PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] The purpose of the present invention is to provide a new glyoxylic acid refining method, which is to refine the crude product with a glyoxylic acid content of 40-50% after concentration and crystallization to remove most of the oxalic acid in the existing process, so as to remove oxalic acid, ethyl Dialdehyde and other impurities can improve the product purity and reduce the color of the finished product, thereby solving the technical problem of poor quality glyoxylic acid products

Method used

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  • Refining method for glyoxalic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] (1) Calcification and removal of oxalic acid impurities

[0039] Sampling and inspection of 50% of the crude product of glyoxylic acid is then put into the calcification kettle, under vigorous stirring, the temperature is controlled at about 25°C, and then calcium carbonate is added. than CaCO 3 : Oxalic acid=0.98:1, react at room temperature for 0.5 hours, then raise the temperature to 80°C and keep the temperature for 2 hours, cool down to 10°C, press filter, the filtrate enters the concentrated crystallization kettle, and discard the filter cake after pressing dry.

[0040] (2) Concentration under reduced pressure to remove residual nitric acid, HCl and other low-boiling impurities

[0041] Transfer the filtrate obtained from the pressure filtration in the previous process into a concentrated crystallization kettle, heat up and concentrate under reduced pressure, control the temperature rise rate in the kettle to 30°C / h, control the vacuum degree in the kettle to 10...

Embodiment 2

[0049] (1) Calcification and removal of oxalic acid impurities

[0050] Sampling and inspection of 50% of the crude product of glyoxylic acid, then putting it into the calcification kettle, stirring vigorously, controlling the temperature at about 20°C, and then putting in calcium hydroxide. The molar ratio of Ca(OH) 2 : Oxalic acid=0.99:1, after casting, react at room temperature for 0.5 hours, then raise the temperature to 75-77°C and keep it warm for 1.5 hours, cool down to 8°C, press filter, and the filtrate enters the concentrated crystallization kettle, and the filter cake is pressed dry and discarded.

[0051] (2) Concentration under reduced pressure to remove residual nitric acid, HCl and other low-boiling impurities

[0052] Transfer the filtrate obtained by pressure filtration from the previous process to a concentrated crystallization kettle, heat up and concentrate under reduced pressure. When the inner solution is concentrated to a concentration of 78.5%, the co...

Embodiment 3

[0060] (1) Calcification and removal of oxalic acid impurities

[0061] Sampling and inspection of 50% of the crude product of glyoxylic acid, then put it into the calcification kettle, under vigorous stirring, control the temperature at about 18°C, put in calcium oxide within 1 hour, the time of adding calcium oxide is 1 hour, and its The molar ratio of oxalic acid is calcium oxide: oxalic acid=0.97:1. After casting, react at room temperature for 0.5 hours, then raise the temperature to 67-69°C and keep it warm for 2.5 hours, cool down to 7°C, press filter, and the filtrate enters the concentrated crystallization kettle, filters Discard the biscuits when they are dry.

[0062] (2) Concentration under reduced pressure to remove residual nitric acid, HCl and other low-boiling impurities

[0063] Transfer the filtrate obtained from the pressure filtration in the previous process into a concentrated crystallization kettle, heat up and concentrate under reduced pressure, control ...

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Abstract

The invention relates to a refining method for glyoxalic acid. The method comprises the following steps: reacting a crude product obtained in a conventional process with a calcification agent so as to produce calcium oxalate deposit insoluble in a reaction system, wherein in the crude product, most oxalic acid is removed through condensation and crystallization and content of glyoxalic acid is 40 to 50%; carrying out filtering so as to remove calcium oxalate; and subjecting an obtained filtrate to reduced pressure concentration, crystallization at a low temperature, centrifugal separation and vacuum drying so to obtain a high-purity solid glyoxylic acid refined product. The method provided by the invention adds a refining process for glyoxylic acid on the base of a conventional production process for glyoxalic acid through nitric acid oxidation of glyoxal to remove oxalic acid and glyoxal in the crude product of an aqueous glyoxalic acid solution and to remove impurities like by-products produced in the process of an oxidation reaction, which enables purity and quality of the glyoxalic acid product to be improved; and the method has the advantages of a simple process, little equipment investment, convenient operation and control and low production cost and is suitable for industrial production.

Description

technical field [0001] The invention relates to a method for refining glyoxylic acid, which belongs to the technical field of fine chemicals. [0002] Background technique [0003] Glyoxalic acid (Glyoxalic acid, CHOCOOH), also known as formaldehyde-formic acid, dihydroxy-alcoholic acid, is the simplest alkyd acid, which has the properties of both aldehyde and acid. It is an important fine chemical raw material and intermediate, widely used It is used in the synthesis of light industrial products such as spices, medicines, pesticides, papermaking, coatings, paints, leather and food additives. At present, the industrial production methods of glyoxylic acid can be divided into two categories: chemical synthesis method and electrochemical synthesis method. The electrochemical synthesis method includes oxalic acid electrolytic reduction method, etc. Among them, the glyoxal nitric acid oxidation method has been improved for many years, its safety is getting higher and higher, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C59/147C07C51/487C07C51/43C07C51/42
Inventor 鲍应元段小六徐双喜程思远周拥军彭秋知晏浩哲
Owner HUBEI HONGYUAN PHARMA
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