新型反应性B区紫外线吸收剂的合成及性能

以肉桂酸衍生物和γ-氯丙基三甲氧基硅烷为原料,通过酯化反应合成了γ-对甲氧基肉桂酰氧基丙基三甲氧基硅烷等6种硅烷氧基肉桂酸酯类化合物;利用核磁共振和红外光谱对这些化合物的结构进行了表征;考察这些化合物的紫外吸收性能,并根据分子轨道理论对这些化合物的紫外吸收机理进行了探讨。实验结果表明,由于共轭效应、诱导效应和位阻效应,苯环上取代基的种类、数目和位置对化合物的紫外吸收性能具有规律性的影响;γ-对甲氧基肉桂酰氧基丙基三甲氧基硅烷是一个性能优良的反应性B区紫外线吸收剂。其紫外吸收区域为248～355nm,最大吸收波长为307nm,最大摩尔吸光系数为2.13×104(大于常用的紫外线吸收剂对甲氧基肉桂酸正辛酯),消光系数为624,防光指数为62.45。

Synthesis and Properties of Novel Reactive B-Area Ultraviolet Absorbents

(p-Methoxycinnamoyloxypropyl)trimethoxy silane,(m-chloromethoxycinnamoyloxypropyl)trimethoxy silane,(cinnamoyloxypropyl)trimethoxy silane,(2,3-dimethoxycinnamoyloxypropyl)trimethoxy silane,(3,4-dimethoxycinnamoyloxypropyl)trimethoxy silane and(2,6-dimethoxycinnamoyloxypropyl)trimethoxy silane were synthesized by esterification of cinnamic acid derivatives with γ-chlorpropyl trimethoxy silane.Their structures were characterized by means of NMR and IR.Their performances in ultraviolet absorption were investigated from view point of molecular orbital theory.Type,number and position of substitute groups on benzene ring affect ultraviolet absorptivity of the compounds due to conjugation,iduction and steric effects.(p-Methoxycinnamoyloxypropyl)trimethoxy silane is an excellent reactive B-area ultraviolet absorbent.Its ultraviolet absorbing wavelength range is from 248 to 355 nm.The wavelength of maximum ultraviolet absorbing is 307 nm and the maximum molar absorptivity is 2.13×104.It is higher than that of octyl p-methoxylcinnamate usually used as B-area ultraviolet absorbent.Its extinction coefficient and lightproof exponent are 624 and 62.45,respectively.