Process for preparing Biphenols
AssigneeMitsui Petrochemical Industries, Ltd.
InventorsMichio Tanaka, Yoshito Kurano, Katsuo Taniguchi
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Abstract
Processes for preparing biphenols by oxidation coupling of phenols, to which the present invention is directed, are characterized in that said oxidation coupling reaction is carried out under such conditions that the same diphenoquinones as those produced as by-products at the time when said oxidation coupling is effected are added to the reaction system. According to a preferred embodiment of the invention, moreover, the yield of biphenols can be enhanced by the reuse in the abovementioned reaction of diphenoquinones recovered from the reaction mixture containing the same.
Claims12
A process for preparing biphenols by oxidation coupling of phenols, characterized by carrying out said oxidation coupling reaction at a temperature of 70-300.degree. C. in the presence of molecular oxygen under such conditions that the same diphenoquinones as the diphenoquinones produced as by-products at the time when said oxidation coupling is carried out are added to the reaction system.
A process for preparing biphenols by oxidation coupling of phenols, said process comprising:
- feeding a reaction mixture comprising a phenol of the formula ##STR6## wherein R.sub.1 and R.sub.2, which may be the same or different, each represent a hydrocarbon radical of 1 to 8 carbon atoms or an alkoxy group of 1 to 8 carbon atoms to an oxidation reactor;
- oxidizing said reaction mixture to form a reaction product comprising a biphenol of the formula ##STR7## wherein R.sub.1 and R.sub.2 are as defined above and a diphenoquinone of the formula ##STR8## wherein R.sub.1 and R.sub.2 are as defined above at a temperature of 70.degree. to 300.degree. C. in the presence of molecular oxygen in said oxidation reactor;
- removing said reaction product from said oxidation reactor;
- separating said reaction product into a first fraction comprising a major portion of said biphenol and a second fraction comprising a major portion of said diphenoquinone;
- recycling at least a portion of said second fraction to said oxidation reactor.
Dependencies are inferred from the claim text.