4 descriptions of chemical products glyoxal, they are the credit of scientific researchers

Some basic information about glyoxal

Colorless or yellow deliquescent crystal or liquid. Soluble in ethanol, ether, soluble in water. It is chemically active and can be added or condensed with ammonia, amide, aldehyde or carboxyl group-containing compounds.

information parameter
INCI Glyoxal
another name Oxalaldehyde
chemical formula C2H2O2
CAS 107-22-2
melting point 15℃
boiling point 51℃
density 1.27 g/cm3
appearance yellow liquid
smiles O=CC=O

Glyoxal solubility: soluble in ethanol, ether, soluble in water.

Glyoxal structure: 

Preparation of glyoxal

As the main raw material of the textile industry, glyoxal has a large demand and is widely used. Therefore, three types of preparation methods for glyoxal are shared here.

(1)Industrial preparation

The main method is glyoxal gas catalytic oxidation and acetaldehyde ammonium nitrate oxidation.

First, ethylene glycol and air can be catalytically oxidized at 250-300 ℃ under the catalysis of copper catalyst, and a large amount of glyoxal can be formed. The active group of the catalyst is copper oxide (including Cu03-8%), and the carrier is alumina or used. Corundum, aluminum sand, prepared by impregnation with copper nitrate. It has a service life of up to one year and can be regenerated by cauterization. After preheating and gasification of ethylene glycol, it is mixed with the recycle gas into the catalytic reactor to control the incorporation of fresh air to prevent excessive oxidation of ethylene glycol. A halogen compound is introduced as an inhibitor of excessive oxidation, and the reaction can be carried out at 275℃ under a pressure of 0.74 MPa, and the reaction product is chilled with water, absorbed and then refined to obtain a finished product. The single pass conversion of ethylene glycol is as high as 80-85%.

Secondly, using copper nitrate as a catalyst, liquid phase oxidation is carried out with nitric acid. Under stirring and sufficient cooling, acetaldehyde and nitric acid are each formulated into a solution of about 50%, and copper nitrate is formulated into a 40% solution, sodium nitrite. Formulated as a 5% solution. First, add a small amount of nitric acid solution and acetaldehyde solution to the reaction pot, then put in sodium nitrite solution, slightly heat until brown red gas is generated, naturally heat up to 30 ° C, and start adding a small amount of nitric acid solution and acetaldehyde solution at the same time. After 4 hours, the reaction temperature was controlled at 40-45 ° C, and the escaped acetaldehyde gas was absorbed into water and added to the reaction vessel, and the reaction was continued for 3 hours. The acetaldehyde was reacted in excess in the reaction (mass ratio, nitric acid: acetic acid = 1:2), and after the reaction was completed, acetaldehyde was recovered by heating to 98 °C. Then add activated carbon to decolorize, cool, filter, and wash. The filtrate and the washing liquid are combined, and the organic acid is distilled off at 70 ° C (21.33 kPa) or less, and the water is repeatedly replenished and then steamed until the acidic cation exchange resin and the weakly basic anion exchange resin in the distillate remove impurities. The exchange and the eluent were concentrated to give a qualified concentration of glyoxal. The yield was about 32% based on acetaldehyde.

(2)Other methods

Oxidized acetaldehyde to prepare glyoxal, selenium dioxide is used to form selenite aqueous solution as oxidant, selenium dioxide is selected to oxidize acetaldehyde to form glyoxal, and at the same time, selenium dioxide is reduced to elemental selenium precipitation; separation reaction product is B. The dialdehyde solution and the elemental selenium; the elemental selenium which is oxidized by the hydrogen peroxide is selenium dioxide, forms a selenite solution, and is returned for oxidizing acetaldehyde to prepare glyoxal. Or using commercially available solid selenium as raw material, firstly oxidizing elemental selenium with hydrogen peroxide to prepare selenium dioxide, using the obtained selenous acid solution to oxidize acetaldehyde to prepare glyoxal, and then recycling selenium. Under optimized conditions, the yield and selectivity of glyoxal and the yield of selenite were both greater than 85%. The advantage is that the reaction conditions are mild, selective and high in yield, and selenium is recycled in the system.

(3)The simplest and most direct method (to the factory to buy) the following sites can be purchased.

http://www.chinaglyoxal.com/category/products/

www.zhonglanindustry.com/

http://www.cosmeticchem.com/

http://www.haihangindustry.com/

Application of glyoxal in various industries

It can form acetals with hydroxyl-containing compounds, mainly used as raw materials for products such as glyoxylic acid, M2D resin, imidazole, etc., as well as insoluble binders such as gelatin, animal glue, cheese, polyvinyl alcohol and starch, and rayon resistance. Shrinkage and the like. In medicine, it is mainly used for special ring imidazole drugs, such as metronidazole, dimetridazole, imidazole, etc.; in the intermediate, it is mainly used as glyoxylic acid, D-p-hydroxyphenylglycine, allantoin, benzene. Enzyme pharynx, berberine, etc.; in light textile, mainly used as clothing finishing agent, 2D resin, M2D resin, etc.; in the paper industry, mainly used as a sizing agent to increase the wet strength of paper; in polymer chemistry is a A very effective cross-linking factor for cross-linking agents; used as a curing agent for cement in the construction industry to improve solidification strength, used as a landslide to prevent soil erosion and prevent landslides.

About the safety of glyoxal

[1]

  1. Health hazards: Harmful if inhaled, ingested or absorbed through the skin. It has a stimulating effect on the skin and can cause dermatitis; steam or mist has a stimulating effect on the eyes, mucous membranes and upper respiratory tract.
  2. Environmental hazard: It is harmful to the environment and can cause pollution to the atmosphere.
  3. Explosion hazard: This product is toxic and irritating.

[2]

Handling precautions: Closed operation, pay attention to ventilation. Operators must be specially trained to strictly follow the operating procedures. Operators are advised to wear self-priming filter dust masks, chemical safety glasses, anti-poison penetrating overalls, and rubber gloves. Keep away from fire, heat, and smoking in the workplace. Use explosion-proof ventilation systems and equipment. Prevent smoke or dust from leaking into the workplace air. Avoid contact with oxidants and alkalis. Lightly load and unload during handling to prevent damage to packaging and containers. Equipped with the corresponding variety and quantity of fire-fighting equipment and leakage emergency treatment equipment. Empty containers may be harmful residues.

[3]

Storage Precautions: The product is usually stored after dilution. Store in a cool, ventilated warehouse. Keep away from fire and heat. The temperature should not exceed 30 °C. The package is sealed and must not be in contact with air. It should be stored separately from oxidants, alkalis and food chemicals, and should not be mixed. Explosion-proof lighting and ventilation facilities are used. It is forbidden to use mechanical equipment and tools that are prone to sparks. The storage area should be equipped with leakage emergency treatment equipment and suitable containment materials.

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