Nylon 66 by condensation of adipic acid and hexamethylene diamine. The production process includes three steps: monomer synthesis, preparation and polycondensation of nylon 66 salt. 1) the preparation of adipic acid is mainly composed of phenol, cyclohexane and acrylonitrile two.
Phenol is with phenol as raw material, using Raney nickel as catalyst in 140 to 2 to 150 DEG C and under the pressure of 3MPa, hydrogenation cyclohexanol, and then 60% to 65% nitrate concentration, in the presence of copper or vanadium catalyst, at 55 to 60 DEG C oxidation to adipic acid. The reaction is as follows:
Cyclohexane method is using cyclohexane as raw material in the presence of cobalt naphthenate or boric acid catalyst, air pressure to produce a mixture of liquid phase oxidation of cyclohexanone and cyclohexanol, and nitrate concentration of 60% in 45 to 60 DEG C oxidation to adipic acid.
The reaction is as follows:
The two method is based on poly acrylonitrile acrylonitrile as raw materials by the electrolytic reduction method has become two adiponitrile, then get the adipic acid in dilute sulfuric acid hydrolysis solution in water heating.
The reaction is as follows:
Hexanediamine prepared mainly adipic acid and butadiene.
Adipic acid method is using adipic acid as raw material, in the presence of phosphate three butyl dehydration catalyst, from 280 to 300 DEG by amination dehydration, adiponitrile, again in the presence of Raney nickel catalyst, 2.8MPa at 90 DEG C and under pressure in acetic acid hydrogenation by hexamethylene diamine.
The reaction is as follows:
The first method is butadiene butadiene chlorinating two chlorobutene isomers, with hydrocyanic acid or sodium cyanide in aqueous solution of two isomers of butene into cyanide cyanide, and then treated with sodium hydroxide, the isomer into 1, 4- two - butene -2 after purification using palladium carbon as catalyst at 300 DEG C under the hydrogenation into hexamethylene diamine.
The reaction is as follows:
By two yuan for nylon acid and amine, need to strictly control the ratio of raw materials such as molar ratio, in order to get a high molecular weight polymer, therefore, must be put in the production of adipic acid and hexanediamine mixture made of nylon 66 salt. Nylon 66 salt are prepared respectively the temperature ethanol ethanol solution with adipic acid hexanediamine at 60 DEG C above the mixing and salt precipitation, filtering, alcohol washing, drying, and finally preparing aqueous solution of 63%, use for polycondensation.
The reaction is as follows:
The polycondensation of nylon 66 salt needs to be carried out at high temperature, with the removal of water, to form a linear high molecular weight nylon 66.
The reaction is as follows:
The production process is divided into two kinds: batch method and continuous method. Continuous method is suitable for mass production, and the production of nylon 66 in the world. Intermittent method is only used in two cases: one is the production of special or test grade; two is in the production capacity of 4 500t A small device.
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