Methyl-di:tert.-butyl:phenol purification - by crystallisation from aq. methanol at low temp.

摘要

Purificn. of 4-methyl-2,6-di-t-butylphenol (I) comprises crystallising at 0-5 degrees C from methanol contg. 3-10 w/w % of water, the ratio of solute to aq. methanol ranging from 1:1 to 1:4. The prod. is made by O-alkylation of phenol then aminomethylation and hydrogenolysis of the resultant N,N-dimethyl-3,5-di-ti-butyl-4-hydroxybenzylamine. Aq. methanol containing 3% of water leads to increased losses of prod. The prod. is a colourless stabiliser for synthetic rubber and polymers, an antioxidant for oils, fuels and other petroleum prods. as stabiliser in foods and drugs. The process removes impurities such as 2,6-di-t-butylphenol 2,4,6-tri-t-butylphenol and 2,6-di-ti-butyl-4-methylcyclohexanone with reduced losses of the desired prod. which is obtd. at a purity of =99.95%.