邻二甲苯气相氧化制2-甲基苯甲醛工艺研究

Process for the Oxidation of o-Xylene to 2-Methylbenzaldehyde in Gas-Phase

以Mg,K和Cs改性的VO_(x)/SiO_(2)为催化剂,氧气为氧化剂,在固定床反应器中以邻二甲苯为原料氧化合成2-甲基苯甲醛,系统地考察了改性催化剂种类、反应温度、氧气与原料物质的量之比以及液时空速对氧化反应的影响。结果表明:催化剂表面碱性的增加有利于提高2-甲基苯甲醛的选择性。较优的反应条件为:以K-VO_(x)/Si O_(2)为催化剂,反应温度为400℃,氧气与邻二甲苯物质的量之比为4.5,邻二甲苯液时空速为0.36 h^(-1)。优化条件下,邻二甲苯氧化合成2-甲基苯甲醛具有较高的催化反应性能,邻二甲苯的转化率为10.5%,2-甲基苯甲醛的选择性达到98%以上。K-VO_(x)/SiO_(2)催化剂的稳定性较好,具有良好的工业应用前景。

The catalytic oxidation of o-xylene to 2-methylbenzaldehyde with oxygen in fix-bed reactor had been studied using Mg,K or Cs modified VO_(x)/SiO_(2) as catalysts.Effects of catalyst,temperature,molar ratio of oxygen to substrate and space velocity of o-xylene on the reaction were systematically investigated.The results showed that the surface basicity of the catalyst benefited for the selectivity of 2-methylbenzaldehyde.The proper process conditions were optimized:using K-VO_(x)/SiO_(2) as the catalyst,reaction temperature of 400℃,mole ratio of oxygen to substrate of 4.5,and liquid hourly space velocity of 0.36 h^(-1).Under such optimized process conditions,the conversion of o-xylene and the selectivity of 2-methylbenzaldehyde reached 10.5%and 98%,respectively.The catalytic process had good stability and showed good industrial application prospect.