The use of adipic acid, the application of adipic acid - Tianyuan Aviation Material

In recent years, China's adipic acid demand is strong, domestic production can not meet the market demand, so every year from abroad a large number of imports. The editor of dioctyl adipic acid manufacturers today learned about the use of adipic acid! Adipic acid, also known as fatty acids, white crystalline or crystalline powders, is an important organic dibasic acid.

Dioctyl adipate manufacturers introduce the main uses of adipic acid

Adipic acid esters are mainly used as raw materials for nylon 66 and engineering plastics, but are also used in the production of various ester products, as raw materials for polyurethane elastomers, and as acidifiers for various foods and beverages, sometimes even exceeding citric acid and tartaric acid.

Adipic acid esters are also used in medicine, yeast purification, pesticides, adhesives, synthetic leather, synthetic dyes and fragrances.

Adipates are a good pH regulator with a mild and long-lasting sour taste and little change in pH over a large concentration range. According to GB2760-2007, the maximum content of solid drinks is 0.01g/kg; it can also be used for jelly and jelly powder. The maximum dosage of jelly is 0.01g/kg. When used for jelly powder, the amount can be increased according to the punching machine.

Dioctyl adipate supplier introduces the preparation method of adipic acid

In 1937, the American DuPont Company used nitric acid (through the hydrogenation of phenol) to oxidize cyclohexanol, and for the first time realized the industrial production of adipic acid. In the 1960s, the industry gradually adopted the cyclohexane oxidation method, that is, the intermediate product cyclohexanone and cyclohexanol mixture (i.e., ketool oil, also known as KA oil) was first prepared by cyclohexane, and then oxidized KA oil with nitric acid or air.

One step oxidation of cyclohexane

2MP was prepared using cyclohexane as raw material, acetic acid as a solvent, cobalt and bromide as catalysts. React at 90 °C for 10~13 h. Yields of 75%.

Cyclohexane step-by-step oxidation

KA oil can be directly oxidized by air at a temperature of 1.0 to 2.5 MPa and 145 to 180 °C, and the yield can reach 70% to 75%. Metaboronic acid can also be used as a catalyst. Air oxidation can be carried out at 1.0 to 2.0 MPa and 165 °C. The yield can reach 90%, and the ratio of alcohol to ketones is 10:1. The reactants are treated with hot water, the ester is hydrolyzed and layered, boric acid is recovered through the aqueous layer, and boric acid is formed by dehydration to form part of the boric acid for recycling. In the organic layer, the organic ester is saponified with caustic soda, the acid is removed, and the cyclohexane is recovered by distillation.

The oxidation reaction of KA oil is carried out in a two-stage series reactor, the reaction temperature is 60 ~80 °C, 0.1 ~ 0.4 MPa, of which the content of nitric acid is 50% ~ 60%. The catalyst is a copper-vanadium series (copper 0.1%~0.5%, vanadium 0.1%~0.2%), and the yield is 92%~96% of the theoretical value. After the nitric acid is evaporated from the reactant, a high-purity adipic acid can be obtained by crystallization twice.

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