瓦斯液相催化氧化制甲醇实验研究

Experiment of catalytic oxidation of mine gas to methanol in liquid phase

以瓦斯为原料制备甲醇的实验研究,可以充分利用瓦斯资源。采用苯酐-尿素法制备了酞菁铜/分子筛复合物CuPc/Y,进一步将金属钯担栽在CuPc/Y上制备了0.5%Pd-CuPc/Y复合物。以0.5%Pd-CuPc/Y为催化剂、醋酸水溶液为溶剂进行了瓦斯液相催化氧化制甲醇的实验研究。结果表明:甲醇的生成量与反应压力、反应温度、催化剂用量、溶剂的酸度、反应时间存在正相关关系,与对苯醌添加量总体上也遵循正相关规律。在瓦斯初始反应压力4 MPa、催化剂用量2 g、溶剂中CH_3COOH与H_2O体积比4:1、对苯醌用量1 000μmol、反应时间3 h、反应温度130℃的条件下,甲醇的生成量为2 754μmol。分析瓦斯液相催化氧化制甲醇的反应机理,认为0.5%Pd-CuPc/Y在醋酸溶液中催化瓦斯选择氧化制甲醇反应同时遵循亲电取代机理和活性氧物种氧化机理。

This paper describes the preparation of the CuPc/Y,copper phthalocyanine encapsulated inside the supercage of zeolite-Y,using phthalic anhydride-urea solid state synthesis method,the subsequent preparation of 0.5％ Pd-CuPc/Y composite catalyst,using CuPc/Y as support and impregnation method,and the resultant investigation into the experiment on selective oxidation of mine gas to methanol in acetic acid solvent over 0.5％ Pd-CuPc/Y catalyst.The results show the positive correlation between the yield of methanol on the one hand and the reaction pressure,reaction temperature,catalyst dosage,acidity of acetic acid solvent,and reaction time in acetic acid solvent on the other hand,accompanied by a positive correlation law as a whole with amount of p-benzoquinone.The yield of methanol was 2 754 μmol under the reaction condition which was 4 MPa of reaction pressure,2 g of the amount of 0.5％Pd-CuPc/Y,4 to 1 of volume ratio of CH3COOH to H2O in acetic acid solvent,1 000 μmol of the amount of p-benzoquinone,3 h of reaction time and 130 ℃ of reaction temperature.The analysis of the reaction mechanism of mine gas partial oxidation to methanol finds that the selective oxidation of mine gas catalyzed by 0.5％ Pd-CuPc/Y catalyst in acetic acid solution tends to be associated with electrophilic substitution mechanism and oxidation mechanism of reactive oxygen species.