A new solid acid SO_4^(2-)/TiO_2 catalyst modified with tin to synthesize 1,6-hexanediol diacrylate  

新型Sn改性固体酸催化剂SO_4^(2-)/TiO_2催化1,6-己二醇二丙烯酸酯合成（英文）

作　　者：Xiaxia Bai Liuyi Pan Peng Zhao Daidi Fan Wenhong Li 白霞霞;潘柳依;赵鹏;范代娣;李稳宏(西北大学化工学院,陕西西安710069;宝鸡文理学院化学化工学院,陕西宝鸡721013;陕西中医学院药学院,陕西咸阳712046)

机构地区：[1]School of Chemical Engineering, Northwest University, Xi＇an 710069, Shaanxi, China [2]School of Chemistry and Chemical Engineering, Baoji University of Arts and Sciences, Baoji 721013, Shaanxi, China [3]School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang 712046, Shaanxi, China

出　　处：《Chinese Journal of Catalysis》2016年第9期1469-1476,共8页催化学报（英文）

摘　　要：A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,infrared spectroscopy of adsorbed pyridine,temperature-programmed desorption of ammonia and thermal gravimetric analysis.The structure,acidity and thermal stability of the SO4^2-/TiO2-SnO2 catalyst were studied.Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO4^2-/TiO2 catalyst.The total acid sites of the modified catalyst increased and Bronsted acid strength remarkably increased with increasing tin content.The decomposition temperature of sulfate radical in the modified catalyst was 100 ℃ greater and its mass loss was more than twice that of the SO4^2-/TiO2 catalyst.The SO4^2-/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid.The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions：crylic acid to 1,6-hexanediol molar ratio = 3.5,catalyst loading = 7%,reaction temperature = 130 ℃ and reaction time = 3 h.The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.丙烯酸酯单体包括通用丙烯酸酯和特种丙烯酸酯,不仅是高分子化合物的基本单体,也是化工有机反应的原料.特种丙烯酸酯在工业合成中虽然规模小,产量低,但已经应用到皮革、造纸、纺织、涂料、粘合剂和辐射固化技术等许多领域.辐射固化材料主要包括活性稀释剂、光引发剂、齐聚物和添加剂等.其中,齐聚物的主要成分就是丙烯酸酯单体的聚合物.然而,丙烯酸酯的合成工业难度不在合成路线,而是反应所使用的催化剂.浓硫酸和对甲苯磺酸等液体酸催化剂由于后续反应难分离、腐蚀设备、污染环境和催化剂不易回收等缺点,逐渐被固体酸催化剂所替代.而SO_4^(2-)/MOx固体酸催化剂虽然没有这些缺点,但是催化剂比表面积较小,热稳定性较差,酸性难以调节.为了合成1,6-己二醇二丙烯酸酯,本文首先对多种催化剂进行了筛选,获得了活性高且稳定好的SO_4^(2-)/TiO_2-SnO_2改性催化剂.采用N2吸附-脱附、X射线衍射(XRD)、扫描电镜(SEM)、红外光谱(IR)、吡啶红外、氨程序升温脱附和热重等技术考察了催化剂的结构特征、表面酸强度和热稳定性.通过N2吸附-脱附可知,Sn改性后催化剂的比表面积增加到126m^2/,较改性前有明显提高.XRD结果表明,Sn能较好地分散在催化剂载体表面,且随着Sn的加入,催化剂晶粒尺寸逐渐减小.SEM照片进一步证实了N2吸附-脱附和XRD结果.催化剂表面酸性通过吡啶红外和氨程序升温脱附测定.由IR图谱可知,固体酸催化剂SO_4^(2-)/TiO_2-SnO_2中SO_4^(2-)和金属原子的连接方式发生变化,更趋于螯合双齿配位结合.通过吡啶红外可以看出,当Sn添加量为6%时,改性催化剂的酸性位由未改性催化剂的59μmol/g增加到167μmol/g.氨程序升温脱附.结果表明,多次使用后催化剂的酸分布几乎不变,但酸量有所下降,这可能与催化剂表面硫源的损失有关.另外,通过热重对催化剂的热稳定

关 键 词：Solid acid catalyst TIN Sol-gel method 1 6-Hexanediol diacrylate Esterification reaction 

分 类 号：O623.624[理学—有机化学]