气相转移法合成CoAPO-5及其催化性能

Vapor Phase Transport Synthesis of CoAPO-5 Molecular Sieve and Its Catalytic Performance

采用气相转移法(VPT),分别在干胶中加入不易挥发的三乙醇胺,液相中加入易挥发的三乙胺作模板剂合成了 CoAPO-5分子筛,考察了干胶组成对分子筛的结构、晶貌以及对乙酸和正丁醇合成乙酸正丁酯反应中催化性能的影响.采用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)和紫外可见漫反射吸收光谱(UV-Vis DRS)等手段对分子筛进行了表征.结果表明,干胶中Al_2O_3,P_2O_5,CoO,(PrO)_3N 和 H_2O 物质的量之比为1∶1∶0.2∶1∶200,液相中三乙胺与 H_2O 体积比为1∶40,200℃下晶化48 h,所合成的分子筛为具有 AFI 结构的六棱柱晶体.CoAPO-5分子筛用于乙酸和正丁醇的酯化反应,当酸醇比为4∶1,催化剂用量为反应物总质量的1%,115℃下反应5 h,其酯收率可达到93.2%。

Co-substituted aluminophosphate molecular sieves （CoAPO-5） were synthesized by vapor-phase transport. The influence of the gel composition on the products was investigated. The catalyst physicochemical properties were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, fourier transform infrared （FT-IR） and ultra-voilet absorption spectroscopy （UV-Vis DRS）. The results showed that the synthesis conditions affected on the crystalline phase, the acidity, and thereby the catalytic performance of CoAPO-5. CoAPO-5 molecular sieves with AFI topology could be synthesized by crystallizing the gel for 48 h at 200 ℃, while the molar ratio of Al2O3, P2O5, CoO, （PrO）3N to H2O was 1 ： 1 ： 0.2 ： 1 ： 200 and the volume ratio of triethanolamine to H2O was 1 ： 40 in the liquid phase. The yield of the ester was 93.2% under the conditions of molar ratio of acetic acid to n-butanol 4 ： 1, reaction temperature 115 ℃ and the mass fraction of catalyst 1% after reaction 5 h.