摘要
二步法甲酸/醋酸催化玉米芯生产糠醛工艺的水解过程会产生少量的醋酸和甲酸,因此水解液中醋酸和甲酸的质量分数不断增加。为了使糠醛生产中甲酸和醋酸质量分数适合工艺条件,文中采用反应精馏法回收该工艺中过量的醋酸和甲酸。分别考察了回流比、酸水进料流量、甲醇与醋酸进料摩尔比、醋酸质量分数和甲酸质量分数等因素对反应精馏回收甲酸和醋酸效果的影响。通过实验得出了适宜的工艺条件:对甲酸质量分数在0.5%以上、醋酸质量分数20%以下的水解液,酸水进料流量在9.0 mL/min、甲醇醋酸进料摩尔比为3∶1和回流比为5等条件下的处理效果最佳。最佳反应条件下对于醋酸质量分数为20%的水解液,醋酸转化率为50.4%,同时甲酸质量分数降低到0.5%。实验证明此方法在满足二步法生产糠醛工艺对水解液甲酸和醋酸质量分数的要求的同时,可回收过量的甲酸和醋酸。
Reactive distillation was used to recover the formic acid and acetic acid which were generated in the process of furfural production by two-step method through hydrolysis of corncobs using formic and acetic acid as catalyst. This study aimed to maintain the organic acids in corncob hydrolysate in a suitable level to produce furfural. The influences of reflux ratio, feed flow rate, the mole ratio of methanol to acetic acid in feeds, the mass fractions of acetic acid and formic acid on the acid recovery efficiency were investigated. The optimal conditions for the initial mass fraction of formic acid above 0.5 % and initial acetic acid below 20 % are as follows： feed rate 9.0 mL/min, reflux ratio 5, the feed mole ratio of methanol to acetic acid of 3 ： 1. Under the optimal conditions and the initial mass fraction of acetic acid 20% , the conversion of acetic acid is 50.4% , and the mass fraction of formic acid is below 0.5%. The experiment shows that reactive distillation is an effective method to recover the excess organic acids and to keep the formic acid and acetic acid in the hadrolyzate in a proper mass fraction to produce furfural.
出处
《化学工程》
CAS
CSCD
北大核心
2013年第4期16-20,共5页
Chemical Engineering(China)
关键词
醋酸
甲酸
反应精馏
醋酸回收
acetic acid
formic acid
reaction distillation
acetic acid recovery
