摘要
针对对苯二甲酸直接酯化合成高值增塑剂对苯二甲酸二丁酯(DBTP)存在的原料价高难得,三废排放量大,催化剂用量大、难分离且不可重复利用等问题,以绿色环保、可循环使用的Brnsted-Lewis双酸型离子液体1-(3-磺酸)-丙基-3-甲基咪唑氯铁酸盐[HO_3S-(CH_2)_3-mim]Cl-FeCl_3(FeCl_3摩尔分数x=0.67)为催化剂,研究了正丁醇醇解廉价易得的废聚对苯二甲酸乙二醇酯(PET)制备增塑剂对苯二甲酸二丁酯的反应.结果表明:在n(PET重复单元)∶n(正丁醇)=1∶3,m(PET)∶m(催化剂)=5∶1,反应温度210℃,反应时间8h的较佳反应条件下,PET醇解率为100%,产物DBTP和乙二醇(EG)收率分别为97.5%和98.2%.同传统催化剂相比,离子液体催化剂的催化性能更高,且重复使用7次其催化性能未见明显降低.傅里叶-红外光谱(FT-IR)分析表明:PET醇解过程由链内酯键断裂和链末端酯键断裂协同完成.
The synthesis of high value plasticizer dibutyl terephthalate（DBTP）with terephthalic acid by direct esterification method has some drawbacks,such as high raw material price,large emission of three industrial wastes,large amount and difficulty in separate and no reusable of catalyst.In order to solve such problems,a new type of environment-friendly and reusable catalyst,named Brnsted-Lewis diacid ionic liquid（IL）,is proposed to produce DBTP.It is found that diacid IL 1-（3-sulfonic）-propyl-3-methylimidazolium chloroironinate[HO3S-（CH2）3-mim]Cl-FeCl3（molar fraction xof FeCl3 is 0.67）is an efficient catalyst for alcoholysis of low-cost waste polyethylene terephthalate（PET）,and the optimum reaction conditions are obtained as follows：n（PET repeat units）∶n（n-butanol）=1∶3,m（PET）∶m（catalyst）=5∶1,reaction temperature 210 ℃ and reaction time 8 h.Under the above reaction conditions,the conversion of PET reaches 100%,and the yields of DBTP and ethylene glycol（EG）are 97.5% and 98.2%,respectively.Additionally,compared with traditional catalysts,the IL catalyst has best performance,and the proposed catalyst separated from the product can be reused for seven times without obvious decrease in its catalytic performance.The mechanism of PET chains scission is proved to be a combination of chain end and random chain scission by Fourier transforminfrared spectroscopy（FT-IR）analysis.
作者
李海燕
刘仕伟
于世涛
LI Haiyan;LIU Shiwei;YU Shitao(College of Chemical Engineering,Qingdao University of Science and Technology,Qingdao 266042,China;Key Laboratory of Biomass Energy and Materials of Jiangsu Province,Nanjing 210042,China)
出处
《大连理工大学学报》
EI
CAS
CSCD
北大核心
2018年第4期342-347,共6页
Journal of Dalian University of Technology
基金
山东省重点研发计划项目(2015GSF116008
2016GGX107001)
江苏省生物质能源与材料重点实验室开放基金资助项目(JSBEM201802)
