adipic acid
Adipic acid
Abbreviation: AA.
Aliases: hexane dicarboxylic acid, fertile acid, 1,4-butane dicarboxylic acid.
English name: adipic acid; hexane diacid; hexane dicarboxylic acid; hexanedioic acid, 1, 4-butanedicarboxylic acid, etc.
The molecular formula is C 6 H 10 O 4 and the molecular weight is 146.14. CAS is numbered 124-04-9 .
Structure: HOCO (CH 2 ) 4 COOH.
Physical and chemical properties
White odorless crystalline solid powder. Soluble in alcohol, slightly soluble in water, the aqueous solution has a sour taste. Oil-water partition coefficient lgPow = 0.08 (measured value) or -0.10 (calculated value). 0.1% aqueous solution pH = 3.2 at 25 ° C, 0.4% aqueous solution pH = 3.0, 2.5% aqueous solution pH = 2.7. Dissociation coefficient (25 ° C) K 1 = 3.90 × 10 -5 , K 2 = 5.29 × 10 -6 . Typical physical properties of adipic acid are shown in Table 5-45.
Method
The production methods of adipic acid mainly include cyclohexane method, butadiene method, cyclohexene method and phenol method.
The cyclohexane method is made of cyclohexane as raw material, oxidized in the presence of air, nitric acid, and metal catalysts, and then refined to obtain adipic acid. The cyclohexane method is currently the main method used in the production of adipic acid in the world, and its output accounts for more than 90% of the total output. Its advantages are that the technology is mature, the product yield is high, and the product purity is high, but the process is more complicated.
The cyclohexene method is a process using benzene as a raw material. It is a new process developed by Asahi Kasei Company in Japan and is currently in the trial production stage. The butadiene method was developed by BASF in Germany. It can be used as a raw material from a refinery's mixed C 4 . The price is low and the production cost is low. The disadvantage is that there are many production steps, the process is complicated, and high-pressure equipment is required. The phenol method is a technology that uses phenol as a raw material to oxidize to produce adipic acid. The production cost is high and the environmental pollution is large. It is basically eliminated at present. Characteristics and uses
Adipic acid is the most valuable diacid among aliphatic diacids. Adipic acid has the general properties of aliphatic diacids, including salt-forming reactions, esterification reactions, amidation reactions, etc. The main use of adipic acid is as a raw material for three categories of products, namely: synthesis of nylon 66 salts, and then the manufacture of polyamide resins and fibers (nylon 66). Nylon 66 is the largest end point market of adipic acid; synthetic polyester polyols, used in the production of polyester-type polyurethane; adipic acid diester plasticizer. In addition, it can be used in the production of advanced lubricants and food additives (sour taste agents for food and beverages).
Polyurethane is an important application field of adipic acid. Adipic acid-based polyester glycol (polyol) is used to produce polyurethane elastomer, polyurethane leather, polyurethane shoe material, polyurethane adhesive, etc.
Manufacturer
German LANXESS company, German BASF company, French Rhodia company, American INVISTA company, American Solutia company, China National Petroleum and Natural Gas joint stock company Liaoyang Petrochemical Branch, Henan Shenma Nylon Chemical Co., Ltd., Taiyuan Chemical Industry Group Co., Ltd., Zhejiang Ningbo Minte Nylon Industry Co., Ltd., Liaoyang Tiancheng Chemical Co., Ltd., etc.
