二氧化硅负载镍铝水滑石的制备及其催化合成安息香乙醚的研究

NiAl-LDHs/SiO_2 Composite:Preparation and Application in Benzoin Ethyl Ether Synthesis

采用共沉淀法制备了以二氧化硅为载体,表面包覆镍铝水滑石的NiAl-LDHs/SiO2复合物,借助XRD、IR及N2吸附-脱附等手段对合成物进行了表征,并将其应用于苯甲醛与乙醇反应生成安息香乙醚反应中进行活性评价。结果表明,复合物中镍铝水滑石与二氧化硅以稳定的Si-O-Al和Si-O-Ni键结合,镍铝水滑石均匀分布于二氧化硅表面,且生成的复合物比表面积较大;当镍铝水滑石负载量为20%时,在反应温度为70℃﹑反应时间为60 min条件下,NiAl-LDHs/SiO2催化苯甲醛与乙醇反应的苯甲醛转化率为61.8%,安息香乙醚选择性接近100%,其催化效果明显优于单一的NiAl-LDHs。

A surface-covered NiAl-LDHs composite NiAl-LDHs/SiO2 was prepared by coprecipitation method using silicon dioxide as supporter.The composite was characterized using X-ray diffraction（XRD）,Fourier transform infrared（FTIR） and N2-adsorption/desorption measurement,and its catalytic performance was evaluated in terms of benzoin ethyl ether synthesis by reaction between benzaldehyde and methanol.The results show that the NiAl-LDHs and SiO2 are combined each other through the stable chemical bond of Si-O-Al and Si-O-Ni in the composite.NiAl-LDHs is distributed uniformly on the surface of SiO2,and the composite has high specific surface area.Additionally,the synthesis of benzoin ethyl ether was performed with NiAl-LDHs/SiO2 of 20% LDHs loadings as the catalyst at 70 ℃ for 60 min.The results show that conversion rate of benzaldehyde could reach 61.8% with the selectivity of benzoin ethyl ether nearly 100% and that NiAl-LDHs/SiO2 has higher catalytic activity than single NiAl-LDHs.