四氢呋喃聚合介孔催化剂Zr-PHTS合成、表征及反应性能

在水-有机溶剂复合体系中,以P123为结构导向剂水热直接合成了锆掺杂介孔固体酸催化剂(Zr-PHTS),运用XRD、TEM、N2吸附-脱附以及NH3-TPD、Py-FTIR等手段对催化剂进行了表征.结果表明,在硅锆摩尔比20-100考察范围内,所得Zr-PHTS样品均显示有序二维六方晶相结构,具有以L酸为主的中等强度的酸性中心;随着锆引入量的变化Zr-PHTS的比表面积仅显示少量的变化,孔径维持在9.8 nm;在四氢呋喃聚合反应中Zr-PHTS显示出较好的催化活性,硅锆摩尔比30的样品表现出最佳的催化性能,聚合物收率达到40.4%,数均分子量2 135,推测催化剂表面酸性和孔结构决定了催化剂对四氢呋喃的聚合性能.

Synthesis, characterization and catalytic activity of Zr-PHTS for THF polymerization

The mesoporous Zr-PHTS solid acid using the P123 triblock copolymer as a structure directing agent were prepared by the one-pot hydrothermal method in water-organic solvent system. These prepared samples were characterized by powder X-ray diffraction (XRD), TEM, N2 sorption isotherms, IR spectra of pyridine adsorption, and NH3-TPD. The characterization results indicated that 2D hexagonal mesoporous structure was retained on Zr-PHTS catalysts. The acidic examination showed that all materials had medium acidity dominated by Lewis acid sites according to the analysis of Pyridine adsorption and NH3-TPD. With the increasing Si/Zr molar ratio from 20 to 100, the BET surface areas of Zr-PHTS were varied a little, the pore diameters were kept at 9.8 nm. The polymerization reaction of THF showed the mesoporous Zr-PHTS solid acid an excellent catalyst. The Zr-PHTS-30 sample had the highest catalytic activity among the prepared catalysts, the yield was 40.4 % and the average molecular weight of the polymer maintained 2135. Such results could be related to the larger pore size and moderate acidic sites.