糠醛加盐复合萃取剂萃取精馏分离苯和正庚烷

采用糠醛加盐复合萃取剂萃取精馏分离苯和正庚烷,考察了盐的种类及含量、萃取剂与原料液的体积比(溶剂比)、超声波等因素对正庚烷与苯相对挥发度(αHB)的影响。实验结果表明,在Al(NO3)3,CaCl2,KSCN,NaNO2,KI5种盐中,KSCN对提高αHB的效果较好;当溶剂比为2.0时,采用糠醛-KSCN复合萃取剂(KSCN质量分数13%),可使αHB达到4.24;超声波处理可提高αHB,当溶剂比为2.0时,对于苯-正庚烷-糠醛物系αHB可提高到3.14,对于苯-正庚烷-糠醛-KSCN物系αHB可达5.16。

Separation of Benzene and n-Heptane by Extractive Distillation with Furfural and Salt

Separation of benzene from n-heptane was carried out by extractive distillation with composite extractant of furfural and salt.Effects of type and concentration of salts,volume ratio of extractant to feed(extractant ratio) and ultrasonic on relative volatility of n-heptane to benzene(αHB) were investigated.Among various tested salts,namely,Al(NO3)3,CaCl2,KSCN,NaNO2 and KI,KSCN is the most effective to increasing of αHB.When extractant ratio is 2.0,by using furfural-KSCN composite extractant(mass fraction of KSCN 13%) αHB reaches 4.24,obviously higher than that using only furfural as extractant where αHB is merely 2.97.The presence of ultrasonic improves αHB remarkably,when extractant ratio is 2.0 in the case of n-heptane-benzene-furfural-KSCN system with ultrasonic,the αHB mounts to 5.16.