China Plastics Network talks about the production process of opp

The production methods of o-phenylphenol mainly include separation methods and synthesis methods. The production method of o-phenylphenol (OPP) can be divided into two methods, a separation method and a synthesis method.

Separation method for recovery from distillation residue for phenol production by sulfonation

The process of opp is as follows: the distillation residue of phenol contains about 40% of phenylphenol, and the other components are phenol, inorganic salts, water, and the like. After vacuum distillation, the mixed phenylphenol fraction is separated, the vacuum degree is 400-500 mmHg, and the temperature starts at 100-75 °C, but it does not exceed 135 °C. The mixture (mainly 2-hydroxybiphenyl and 4-hydroxybiphenyl) is heated and dissolved in trichloroethylene, and the 4-hydroxybiphenyl crystal is separated by cooling, centrifugally filtered and dried to obtain 4-hydroxybiphenyl. The mother liquor is washed with a sodium carbonate solution, and a dilute alkali solution is added to form a 2-hydroxybiphenyl salt. After static separation, the upper layer of 2-hydroxybiphenyl sodium salt is dehydrated under reduced pressure to obtain a finished sodium salt. Due to resource constraints, the production of o-phenylphenol by the separation process is very limited.