H5CoW12O40 supported on nano silica from rice husk ash: A green bifunctional catalyst for the reaction of alcohols with cyclic and acyclic 1,3-dicarbonyl compounds
作者:Ezzat Rafiee、Maryam Khodayari、Masoud Kahrizi、Reza Tayebee
DOI:10.1016/j.molcata.2012.03.005
日期:2012.6
abundant agricultural by-product. The present research work deals with the production of nano silica powders, with high surface area and in amorphous form, from RHA using optimized technique. 12-Tungestocobaltic acid, H5CoW12O40 (CoW), was supported on silica from RHA to produce silica supported CoW (CoW/NSiO2) as a nano catalyst. The characterization data derived from FT-IR reveal that the Keggin structure
稻壳灰(RHA)是一种丰富的农业副产品。本研究工作涉及使用优化技术从RHA生产高表面积和无定形形式的纳米二氧化硅粉末。由RHA将12-钨钴酸H 5 CoW 12 O 40(CoW)负载在二氧化硅上,以制备作为纳米催化剂的二氧化硅负载的CoW(CoW / NSiO 2)。从FT-IR得出的表征数据表明,CoW的Keggin结构在CoW / NSiO 2中保持完整。TEM图像显示该催化剂为球形,平均粒径为10nm。催化剂的酸度通过电位滴定法用n-丁胺。令我们惊讶的是,这种非常强固的固体酸催化剂显示出极好的酸位分布,这表明该催化剂与负载在商业二氧化硅上的CoW(CoW / SiO 2),CoW和K 5 CoW 12相比,具有更高的表面活性位。O 40。发现在CoW / NSiO 2上具有高催化活性。最后,CoW / NSiO 2用作将线性1,3-二羰基化合物与苄醇进行苄基化反应和由环状1,3-二