Wed April 08, 2015 By: Richa Verma

how BHA and BHT are formed?

Expert Reply
Hanisha Vyas
Thu April 09, 2015
BHT (Butylated hydroxytoluene) is chemically derived from phenol.

Industrially, BHT is prepared by the reaction of p-cresol (4-methylphenol) with isobutylene (2-methylpropene) catalyzed by sulfuric acid.

CH3(C6H4)OH + 2 CH2=C(CH3)2 → ((CH3)3C)2CH3C6H2OH

Alternatively, BHT is prepared from 2,6-di-tert-butylphenol by hydroxymethylation or aminomethylation followed by hydrogenolysis.

BHA (Butylated hydroxyanisole) is prepared from 4-methoxyphenol and isobutylene.
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