| 摘要 |
One or more alkylated phenols are prepared by a process which comprises (a) condensing at a temperature below 100 DEG C. a 2,4- or 2,6-dialkylphenol with formaldehyde in the presence of a basic catalyst and a monohydric secondary or tertiary alkanol, there being at least 0.1 mol of alkanol per mol of dialkylphenol, so as to form a 3,5-dialkyl-4-or-6-hydroxybenzyl alcohol and (b) condensing in the presence of a basic catalyst and a monohydric secondary or tertiary alkanol the 3,5-dialkyl-4-or-6-hydroxybenzyl alcohol with respectively a 2,6- or 2,4-dialkylphenol to yield respectively a bis(3,5-dialkyl-4-or-6-hydroxyphenyl) methane. The product of step (a) may also be catalytically hydrogenated at a pressure in excess of 7.8 atmospheres to form a 2,4-dialkyl-6-methylphenol or 2,6-dialkyl-4-methylphenol. The alkylphenols are used as antioxidants. An apparatus for carrying out the processes is described. In an example 2,6-di-tert-butyl-phenol is condensed at 10 degrees with formadehyde in tert.-butyl alcohol containing pottassium hydroxide, the mixture neutralised with carbon dioxide and tert.-butanol is distilled off to give a residue of 3,5-di-tert.-butyl-4-hydroxy alcohol. This substituted benzyl alcohol is either reacted at 77 DEG C. with 2,6-di-tert.-buty-phenol in tert.-butanol containing potassium hydroxide and the mixture cooled to crystallise bis(3,5-di-tert.-butyl-4-hydroxyphenyl) methane or hydrogenated under pressure in isopropanol using a copper chromite catalyst to give 2,6-di-tert.-buty-4-methylphenol. Specifications 806,961, 862,261 889,321 and 893,896 are referred to.
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