(顺)-1,1,1,4,4,4-六氟-2-丁烯的合成研究进展

Progress of preparation of cis-hexafluoro-2-butene

作为氢氟烯烃(HFO)类物质,顺-1,1,1,4,4,4-六氟-2-丁烯(Z-HFO-1336)的臭氧消耗潜值(ODP)为零,温室效应潜值(GWP)极低,对环境影响很小,因其性能与前几代发泡剂相近,被看作新一代绿色环保发泡剂,其合成方法受到氟化工界的广泛关注。至今,Z-HFO-1336的合成方法主要可分为:①直接氟化C4化合物合成;②氟利昂类化合物CFC-113、HCFC-123经偶联反应制备;③由卤代甲烷与卤代烯烃经调聚反应制备。其中直接氟化法虽然路线短,但产物选择性低、催化剂稳定性差;而氟利昂类化合物偶联法污染大,调聚合成存在工艺复杂、收率低等问题。提出了两种具有学术和工业价值的研究路线:①HCFC-123自偶联一步合成Z-HFO-1336,反应涉及C—Cl键的活化、单电子转移(SET)等过程,极具理论研究意义;②以乙烯、三氟丙烯为原料经调聚反应合成,原料来源广泛,催化合成可连续进行,具有很强的工业价值。

Hydrofluoroolefin cis-1,1,1,4,4,4-hexafluoro-2-butene（Z-HFO-1336） has zero ozone depletion potential（ODP） and low global warming potential（GWP）, which replaces trichlorofluoromethane CFC-11, 1,1-dichloro-1-fluoroethane HCFC-141b, and 1,1,1,3,3pentafluoropropane HFC-245fa by good compatibility and chemical stability,is used as new generation foaming materials. Synthesis of the compound mainly includes three types：direct fluorination of C4 compounds,coupling of CFC-113 and HCFC-123,and telomerization of haloalkane with olefin to form chlorofluorobutane by Kharasch reaction. Direct method is too expensive for large scale production, coupling route brings up pollution problems,and complicated Kharasch reaction involves long steps. Two synthesis approaches are proposed：Coupling of HCFC-123 attracts theoretical study,which involves activation of C─Cl bond and single electron transfer process,and simple and practical way using ethylene or trifluoropropene as starting material could be an effective method for plant-scale production.