The bimetallic catalyst Ru-Pt/ γ -Al 2O 3 was prepared by impregnating H 2PtCl 6 and RuCl 3 aqueous solution in the presence of PVP(40 000). Its catalytic performance in selective hydrogenation of \{ p -chloronitrobenzene\}( p -CNB) was studied. The results indicate that the activity of Ru-Pt/ γ -Al 2O 3[\{ n (ruthenium)\}∶ n (platinum)=4∶1] is much higher than that of Ru/ γ -Al 2O 3,while the amount of dehalogenation product(aniline) and other by-products are much fewer than that by using Pt/ γ -Al 2O 3 as the catalyst. There is synergistic effect of ruthenium and platinum in bimetallic catalyst for selective hydrogenation of p -CNB. Under the reaction conditions t =50 ℃, p H 2 = 1.0 MPa, reaction time 60 min,\{ n (substrate)∶\} n (total amount of metal content)=1000∶1,the conversion of p -CNB and the selectivity to p -chloroaniline( p -CNA) by using Ru-Pt/ γ -Al 2O 3 as the catalyst are 48.2% and 85.9%,respectively. The effect of other metal cations(introduced to the reaction system with the corresponding metal chloride solution) on the reaction was investigated. It was found that catalytic performance of Ru-Pt/ γ -Al 2O 3 could be greatly improved by modfication of some metal cations. When Co 2+ and Ni 2+ were used as modifiers for the catalyst Ru-Pt/ γ -Al 2O 3 under above mentioned reaction conditions,the conversions of p -CNB increase to 74.5% and 87.8%,as well as the selectivities of p -CAN increase to 98.9% and 99.4%,respectively. Fe 3+ and Sn 4+ were the best modifiers for Ru-Pt/ γ -Al 2O 3 under the same reaction conditions. The conversions of p -CNB and the selectivities of p -CAN can reach 100% and >99.0%,respectively. However,the catalysts can be poisoned by Zn 2+ and Sn 2+ .
利用羟胺酸BPHA(N 苯甲酰基 N 苯基羟胺)钴配合物Co(BPHA)2作催化剂,对对二甲苯液相氧化反应进行了研究.详细考察了反应温度、催化剂浓度、配体浓度、反应时间和轴配体对该催化反应的影响.实验结果表明:当反应温度为125℃、氧气压力为0.5MPa、催化剂浓度为1.0×10-3mol/L、配体与催化剂的摩尔比为2∶1时、添加四甘醇或聚乙二醇作配体,反应2h时对二甲苯转化率可达41～43%、选择性为92%.本研究丰富了二甲苯选择性氧化的内容,并具有一定的工业应用前景.
Mn complexes with N,N′ bis(furaldehyde)1,2 phenylenediamine(1)、N,N′ bis(furaldehyde) ethylenediamine(2),N,N′ bis(furaldehyde)1,2 diaminopropane(3),N,N′ bis(furaldehyde)1,3 diamino propane(4), and N,N′ bis(furaldehyde) diethylenetriamin(5) were used as catalysts in styrene epoxidation.The influences of different ligand,pH,axial ligand and reaction tiom on reactions were discussed.
