Synthesis and Structure of Copper Hydroxyphosphate and Its High Catalytic Activity in Hydroxylation of Phenol by H2O2
Synthesis and Structure of Copper Hydroxyphosphate and Its High Catalytic Activity in Hydroxylation of Phenol by H2O2
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DOI：
10.1006/jcat.2001.3166
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发表时间：
2001-04
影响因子：
7.3
通讯作者：
F. Xiao;Jianmin Sun;Xiangju Meng;R. Yu;Hongming Yuan;Jia-ning Xu;T. Song;D. Jiang;Da Xu
中科院分区：
文献类型：
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作者：
F. Xiao;Jianmin Sun;Xiangju Meng;R. Yu;Hongming Yuan;Jia-ning Xu;T. Song;D. Jiang;Da Xu
采用水热法合成了Cu 2（OH）PO 4复合氧化物，并对其结构进行了X射线衍射分析。晶体属Pnnm正交晶系，空间群为a =8.058（2），B =8.393（2），c =5.889（2）A。此外，通过热分析（DTA和TG）对样品进行表征，这些结果表明样品在低于650°C下是稳定的。在850°C煅烧后，Cu 2（OH）PO 4脱水生成Cu 4 O（PO 4）2 . N2吸附等温线表明，当样品粒径为150 μm时，无微孔或中孔存在，比表面积仅为1.4m2/g。此外，将该样品用作苯酚过氧化氢羟基化反应的催化剂时，催化数据显示出高的活性，与TS-1相当。考察了溶剂、反应温度、反应时间、催化剂粒度、催化剂用量、苯酚与H2 O2的摩尔比、H2 O2的加入方式等因素对催化反应的影响。用电子自旋共振（ESR）对该催化反应进行了表征，发现在Cu 2（OH）PO 4催化剂上，可能由Cu 2+和H2 O2产生的羟基自由基是苯酚羟基化生成邻苯二酚和对苯二酚的重要中间体.
Abstract A complex oxide of Cu 2 (OH)PO 4 has been successfully synthesized by the hydrothermal method, and its structure was investigated by X-ray analysis. It crystallizes in the orthorhombic space group of Pnnm with a =8.058(2), b =8.393(2), and c =5.889(2) A. Furthermore, the sample was characterized by thermal analysis (DTA and TG), and these results indicated that the sample was stable below 650°C. After calcination at 850°C, Cu 2 (OH)PO 4 was dehydrated to form Cu 4 O(PO 4 ) 2 . The sample isotherm for N 2 showed that there wre no micropores or mesopores, and the surface area was only at 1.4 m 2 /g when the particle size of the sample was 150 μm. Moreover, when this sample was used as a catalyst for phenol hydroxylation by H 2 O 2 , the catalytic data showed high activity, which was comparable to that of TS-1. Various factors that influence this catalytic reaction, such as the solvent, reaction temperature, reaction time, catalyst size, catalyst amount, molar ratio of phenol to H 2 O 2 , and mode of H 2 O 2 addition, were investigated intensively. Additionally, this catalytic reaction was characterized by electron spin resonance (ESR), and it was found that on the Cu 2 (OH)PO 4 catalyst hydroxyl radicals possibly resulting from Cu 2+ and H 2 O 2 were important intermediates for formation of catechol and hydroquinone from hydroxylation phenol.