| 摘要 |
Alkylated phenols are dealkylated in the presence of a hydrogen-containing gas at elevated temperature and pressure by carrying out the reaction in the presence of more than sufficient alkali to neutralise the phenols. Alkylated aromatic hydrocarbons present in the mixture may be dealkylated at the same time. The reaction may be carried out at between 350 DEG and 550 DEG C. and at between 7 and 150 atmospheres pressure. The alkali may be present in quantities ranging from 1,1 to 4,4 equivalents per phenolic hydroxyl and alkalies such as sodium and calcium hydroxide are preferred. The phenolic compounds mentioned are o-cresol, cresylic acid (a mixture of isomeric cresols) and phenolic material derived from coal. Aromatic compounds such as methyl naphthalenes, tetramethyl benzenes and ethyl toluenes may also be present with the phenols. The process may be carried out batchwise or continuously and a flow sheet is given together with a detailed description of the continuous process. In examples (1)-(6) o-cresol is dealkylated under various conditions using 1,1 to 4,4 equivalents of sodium hydroxide, temperatures of 400 DEG -450 DEG C. and at various hydrogen pressures and reaction times ; (7) a cresylic acid containing 92% phenols and 8% alkaryl hydrocarbons is treated with hydrogen under pressure at 460 DEG C. and in the presence of calcium oxide to yield phenol and aromatic hydrocarbons which are removed by steam stripping.
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