氢氧化钾/活性炭催化邻苯二酚与碳酸二乙酯反应合成邻苯二乙醚

实验以邻苯二酚与碳酸二乙酯(DEC)为原料,在液相条件下,以KOH/AC固体碱为催化剂,合成了邻苯二乙醚。研究了邻苯二酚与碳酸二乙酯氧烷基化合成邻苯二乙醚的反应,考察了反应温度、反应时间、催化剂用量、原料摩尔配比等因素对反应结果的影响,并采用CO2程序升温脱附(CO2 H-TPD)对催化剂进行了表征。实验结果表明,当KOH的负载量为20%时,催化剂具有最好的催化性能,催化剂的弱碱性位是催化反应的活性中心。在反应温度为200℃,反应时间为3 h,催化剂用量为反应物总质量的5%,n(DEC):n(邻苯二酚)=4:1的条件下,邻苯二酚的转化率和邻苯二乙醚的选择性分别达到100%和87.7%。

SYNTHESIS OF 1,2-DIETHOXYBENZENE FROM CATECHOL AND DIETHYL CARBONATE OVER KOH/AC

O-ethylation of catechol with diethyl carbonate(DEC) in liquid phase was performed to synthesize 1,2-diethoxybenzene over KOH/AC. The effects of reaction temperature, reaction time, catalyst dosage and molar ratios were investigated. Catalysts were characterized by CO_2 temperature-programmed desorption (CO_2-TPD). The results indicated that the weakly basic sites of KOH/AC were the active sites for the O-ethylation of catechol with diethyl carbonate. KOH/AC with 20% KOH loading had the highest catalytic activity. Under the optimum conditions, i. e. , reaction temperature 200℃, time 3 h, n(DEC): n(Catechol ) 4:1 and catalyst dosage 5%, catechol conversion and the selectivity for 1, 2-diethoxybenzene reached 100% and 87. 7%, respectively.