配位环境对有机钛化合物催化聚酯缩聚反应的影响  

Effect ofcoordination environment on polycondensation of polyester catalyzed by organic titanium compounds

作　　者：苏亚 王勇军 陈文兴[1,2] 吕汪洋 SU Ya;WANG Yongjun;CHEN Wenxing;Lü Wangyang(National Engineering Lab for Textile Fiber Materials and Processing Technology,Zhejiang Sci-Tech University,Hangzhou 310018,China;Zhejiang Provincial Innovation Center of Advanced Textile Technology,Shaoxing 312000,China)

机构地区：[1]浙江理工大学纺织纤维材料与加工技术国家地方联合工程实验室,杭州310018 [2]浙江省现代纺织技术创新中心,浙江绍兴312000

出　　处：《现代纺织技术》2023年第6期92-99,共8页Advanced Textile Technology

基　　金：浙江省重点研发计划项目(2021C01020)。

摘　　要：为探究不同配位环境下有机钛化合物在聚酯缩聚反应过程中的催化性能,采用密度泛函理论(DFT)并结合对苯二甲酸双羟乙酯(BHET)合成聚酯的反应动力学实验,对四甲基酚合钛(Ti·[C_(7)H_(7)O]_(4),Cat1)、乙酰丙酮氧化钛(TiO·[C_(5)H_(7)O_(2)]_(2),Cat2)、异丙基三(二辛基焦磷酸酰氧基)钛酸酯(C_(51)H_(112)O_(22)P_(6)Ti,Cat3)3种有机钛化合物进行研究,分析配位基团的电子效应和空间位阻对有机钛催化活性的耦合影响。DFT计算结果表明,3种活性种的中心钛原子的Hirshfeld电荷数值分别为0.661、0.524、0.600,其亲电能力从大到小的顺序为Cat1、Cat3、Cat2。结构分析结果表明,中心钛原子的配位空间从大到小的顺序为Cat2、Cat1、Cat3。催化反应动力学实验表明,Cat1、Cat2、Cat3催化BHET合成聚酯的反应活化能分别为72.41、80.16、102.47 kJ mol,Cat1的催化活性最高,说明配位基团的电子效应和空间位阻共同影响钛催化剂的催化活性。研究结果可为钛系催化剂的设计及调控提供一定的理论基础和参考依据。Polyethylene terephthalate(PET)has excellent physical and chemical properties and is the most commonly used polyester material.The polycondensation stage of polyester synthesis requires the participation of catalysts.At present,antimony-based catalysts are widely used in industrial production.Antimony-baseds,as a kind of heavy metal compound,have biological toxicity and will cause harm to human health and ecological environment.With the increasing awareness of healthy,the design and development of non-toxic and non-hazardous polyester catalysts has become an important hotspot in the field of polyester research.The titanium-based catalysts are expected to replace the antimony-based catalysts due to the advantages of environmental protection,strong catalytic activity and abundant resources.The high activity of titanium-based catalysts not only increases the reaction rate of the PET polycondensation process,but promotes side reactions such as thermal degradation and thermo-oxidative degradation,which is one of the most prominent problems limiting the application of titanium-based catalysts in polyester synthesis.The regulation of the catalytic activity of titanium-based catalysts is therefore crucial.To investigate the catalytic performance of organotitanium compounds in the condensation synthesis of polyesters under different coordination environments,firstly,density functional theory(DFT)quantum chemistry method was used to study tetramethylphenol titanium(Ti·[C_(7)H_(7O)]4,Cat1),acetyl acetone titanium oxide(TiO·[C 5H 7O 2]2,Cat2),isopropyl tri(dioctylpyrophosphoxy)titanate(C_(51)H_(112)O_(22)P_(6)Ti,Cat3),and the coupling mechanism of electronic effects and steric hindrance of coordination groups on catalytic activity of organotitanium was analyzed theoretically.The Gaussian software was used to carry out structural optimization and energy calculations for the three organotitanium compounds,and the wave functions were extracted from the calculation results.The wave function analysis was carried out by using th

关 键 词：聚酯 有机钛化合物 缩聚反应 催化活性 配位基团 

分 类 号：TQ314.2[化学工程—高聚物工业]