环己烷气相氧化裂解制低碳烯烃

Study on Production of Light Alkenes by Gas Phase Oxidative Cracking of Cyclohex ane

环己烷气相氧化裂解与传统的热裂解工艺相比,氧气的介入使环烷烃在较低温度下就能开环裂解。在反应温度650℃时,环己烷发生气相氧化裂解反应,环己烷转化率超过70%、烯烃收率为30%左右,而在此条件下环己烷的热裂解反应几乎不发生。在反应温度750℃、n(环己烷)/n(O2)为0 8、停留时间小于0 7s条件下,采用空气代替纯氧进料,环己烷转化率为90%左右,烯烃收率超过48%,CO收率为14%左右,CO2收率仅为1%左右。

Ring cleavage of cyclohexane became rather easy in gas phase oxidativ e cracking of cyclohexane due to oxygen introduction,as compared with alkene p roduction by traditional thermal cracking of cycloalkanes.Pyrolysis of cycloh e xane hardly occured at 650 ℃ but 70% conversion of cyclohexane and 30% yield of alkenes could be obtained in gas phase oxidative process.If replacing air by o xygen about 90% conversion of cyclohexane,higher than 48% yield of alkenes and about 14% yield of CO could be obtained with only about 1% yield of CO2,at 75 0 ℃,mole ratio cyclohexane/oxygen 0.8,and contact time less than 0.7 s.