乙酸存在下磷酸铁催化对甲酚气相选择性氧化(英文)

Gas-Phase Selective Oxidation of p-Cresol in the Presence of Acetic Acid over Iron Phosphate Catalyst

在乙酸存在和空气气氛下,以磷酸铁为催化剂进行了对甲酚气相选择氧化生成对羟基苯甲醛和对羟基苯甲醇的反应.考察了不同乙酸/对甲酚比和反应温度对反应产物分布的影响.结果表明,加入乙酸可抑制目标产物深度氧化,促进气相反应中高选择性地生成对羟基苯甲醛和对羟基苯甲醇.在反应温度为250℃,乙酸/对甲酚比为0.9,催化剂用量为0.35g和对甲酚流速为1.92g/h时,生成对羟基苯甲醛的选择性为34.4%,生成对羟基苯甲醇的选择性为65.6%.

A challenging subject in catalysis is the conversion of a liquid-phase catalytic process to a gas-phase process. p-Hydroxybenzaldehyde is a useful chemical intermediate usually obtained by the liquid-phase oxidation of p-cresol in an alkali methanol medium . Although good selectivity for p-hydroxybenzaldehyde has been achieved, the use of methanol as the solvent brings an explosion risk in operation and a large amount of NaOH in the solvent has to be neutralized, which are the main disadvantages. These problems can be circumvented by the gas-phase oxidation of p-cresol, in which the potential advantage of product separation and convenient control of the reaction may be realized.