| 摘要 |
<p>A process for the production of polyalkyl phenol comprises feeding to a reaction zone an aliphatic alcohol, an alkyl phenol containing at least one unsubstituted position in the nucleus, and in the reaction zone subjecting the alkylphenol to vapour phase alkylation with the aliphatic alcohol at a temperature in the range 250-450 DEG C., in the presence of a solid alkylation catalyst preferably activated alumina. The phenol may be monomethyl or dimethyl phenol e.g. 3,5-dimethyl phenol. Preferably the alkylation is carried out at substantially atmospheric pressure and at a temperature in the range of 250-450 DEG C. In an example a mixture of 3,5-dimethyl phenol and methyl alcohol in a molecular ratio of 1 to 1 are passed over activated alumina heated to 360 DEG C. and the product condensed, and from this mixture of phenols 2,3,5-trimethyl phenol was isolated. In a further example equimolar amounts of metacresol and methyl alcohol are passed over granular activated alumina at 350-360 DEG C. and the product which contains various di- and tri-methyl phenols was separated by fractional distillation to produce 2,5-xylenol which was reacted by recycling through the column with methanol to trimethyl phenols.</p> |
