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Source:Transform the World with Simplicity
Phthalic ether (Diphenyl) is a commonly used chemical raw material, widely used in plastics, coatings, spices, medicine and other fields. Its manufacturing methods are mainly the following:
1. Sulfonation
Sulfonation is one of the classical methods for the manufacture of phthalic ether. The raw materials of the method are phthalic acid and sulfuric acid, and phthalic acid disulfonic acid is obtained by sulfonation reaction, and then esterification reaction with phenolic compound is carried out to obtain phthalic ether. The specific steps are as follows:
(1) Phthalic acid and sulfuric acid are mixed and heated to 140-160 ° C. for sulfonation reaction to generate phthalic acid disulfonic acid.
(2) The phthalic acid disulfonic acid is mixed with a phenolic compound (such as phenol), and heated to 180-220 ° C. for esterification to produce phthalic ether. The advantages of
sulfonation method are that the raw materials are readily available, the reaction conditions are milder and the yield is higher. However, this method requires the use of a large amount of sulfuric acid, the equipment is seriously corroded, the waste water discharge is large, and the environmental protection pressure is high.
2. catalytic oxidation
catalytic oxidation method is a relatively new method for the manufacture of phthalate ether. The raw material of the method is phthalonitrile, phthalic acid is obtained by catalytic oxidation reaction, and then the esterification reaction with phenolic compound is carried out to obtain phthalic ether. The specific steps are as follows:
(1) Phthalonitrile is mixed with a solvent (such as acetic acid), a catalyst (such as cobalt salt) is added, and a catalytic oxidation reaction is carried out at 120-150 ° C. to generate phthalic acid.
(2) Phthalic acid is mixed with a phenolic compound (such as phenol), a catalyst (such as sulfuric acid) is added, and an esterification reaction is carried out at 180-220 ° C. to produce a phthalic ether. The advantages of
catalytic oxidation method are mild reaction conditions, higher yield and less wastewater discharge. However, this method requires the use of a catalyst, requires high equipment, and the price of the raw material phthalonitrile is high.
3. Etherification
Etherification is a direct synthesis of phthalates. The raw materials of the method are phenol and formaldehyde, and phthalic ether is obtained by etherification reaction. The specific steps are as follows:
(1) Phenol and formaldehyde are mixed according to a certain ratio, a catalyst (such as hydrochloric acid or sulfuric acid) is added, and an etherification reaction is carried out at 80-120 ° C. to generate phthalic ether. The advantages of the
etherification method are that the raw materials are easily available, the reaction steps are simple, but the yield is low, a large amount of catalyst is required, and the generated wastewater contains harmful substances such as formaldehyde, and the environmental protection pressure is high.
To sum up, sulfonation, catalytic oxidation and etherification are all methods for manufacturing phthalates, and each method has its advantages and disadvantages. In actual production, a suitable method can be selected according to specific conditions. At the same time, in order to reduce the pressure of environmental protection and improve economic benefits, further research and improvement of manufacturing methods are needed to improve yield and product quality.