Sn(OBu^n)_4溶胶-凝胶体系的水解缩合反应动力学  

KINETICS OF HYDROLYSIS AND CONDENSATION IN Sn(OBu^n)_4 SOL-GEL SYSTEMS

作　　者：黄瑞安[1] 侯立松[1] 赵启涛[1] 

机构地区：[1]中国科学院上海光学精密机械研究所

出　　处：《硅酸盐学报》2004年第6期684-688,共5页Journal of The Chinese Ceramic Society

摘　　要：研究了乙酰丙酮(acetylacetone)改性正丁醇锡(tinalkoxide)在氢氟酸、盐酸、氢溴酸、硝酸、乙酸和氨催化剂作用下的溶胶凝胶体系的动力学过程。利用近似线性聚合生长模型求出了不同催化剂作用下改性醇盐的平均缩合反应速率以及溶胶团簇的平均官能度,催化剂对平均缩合反应速率的影响按大小依次为硝酸、盐酸、乙酸、氨水和氢溴酸,各溶胶体系的平均官能度均为略大于2.0。氢氟酸作催化剂的体系产生白色沉淀。催化剂对体系凝胶时间影响大小依次为氨水、乙酸、盐酸、硝酸和氢溴酸。利用部分电荷模型计算了不同催化剂作用下改性锡醇盐分子体系的电荷分布,讨论了不同催化剂对改性锡醇盐水解和缩合反应的催化机理。Kinetics of hydrolysis and condensation of acetylacetone-modified Sn(OBu^n)_4 was studied under the reaction of catalysts of hydrochloric, hydrobromic, nitric, acetic acids and ammonia. The average functionalities of polymers, which are all a bit larger than (2.0), and the average rates of condensation of the modified tin butoxide were obtained based on the nearly-linear growth model. The influence of catalysts on the average rates of condensation of the modified tin alkoxide is in turns of nitric, hydrochloric, acetic acids, ammonia and hydrobromic acid. All the sol systems are transparent and stable except for the hydrofluoric-catalyzed system, in which precipitation occurs. The gelation times are affected by catalysts in turns of ammonia, acetic, hydrochloric, nitric and hydrobromic acids. Charge distributions in modified tin alkoxides were also calculated by partial charge model. The mechanisms of hydrolysis and condensation of the modified tin butoxide under different catalysts are also discussed.

关 键 词：溶胶-凝胶法 锡醇盐 水解与缩合 动力学 

分 类 号：TB383[一般工业技术—材料科学与工程]