The effect of Pd/Al2O3 pretreatment on catalytic activity in cyclopentane/deuterium exchange

Big variations in overall activity and product selectivity in the cyclopentane/deuterium exchange reaction were found in effect of various pretreatments of two chlorine‐free Pd/γ‐Al₂O₃ catalysts. The most important changes are observed when severely prereduced (at 600 °C) Pd/Al₂O₃ catalysts have been reoxidised and mildly rereduced: the multiple type of exchange, typical of mildly pretreated Pd catalysts, is replaced by a stepwise mode, and a big increase in catalytic activity occurs. At this state, the Pd/γ‐Al₂O₃ catalysts retain some water (as surface hydroxyls) generated by reoxidation and mild reduction. Deuterium spillover from Pd onto alumina and changes in acidity of alumina are invoked to rationalize the kinetic results. Changes in the state of Pd after various pretreatments, as probed by temperature‐programmed hydride decomposition, can hardly be correlated with changes in the catalytic behaviour in the exchange reaction. This revised version was published online in August 2006 with corrections to the Cover Date.     

金属卟啉仿生催化环戊烷选择氧化的研究

研究了金属卟啉仿生催化环戊烷选择氧化的反应。结果表明,反应时间、温度、压力、催化剂浓度和类型对反应具有明显的影响。其中,反应温度和压力对反应总选择性影响最大,反应适宜的条件是温度145℃,压力2.5 MPa,时间4 h,金属卟啉用量14×10~(-4)mol%,搅拌速率800 r/min。不同中心金属离子的金属卟啉催化环戊烷氧化的活性顺序为FeCoMn。其中,催化效果较好的催化剂为T(o-NO_2)PPFeCl,主产物戊二酸、环戊醇和环戊酮的总收率和总选择性分别为6.2%和86.1%。     

Tris(2-octyldodecyl)cyclopentane,a low volatility,wide liquid range,hydrocarbon fluid

Tris(2–octyldodecyl)cyclopentane, prepared by the hydrogenation of the product of alkylation of cyclopentadiene by 2–octyldodecanol, is a wide liquid range hydrocarbon fluid (pour point, −57°C; vapour pressure at 20 °C, 1 × 10⁻¹²). This new fluid compares favourably with other hydrocarbons and per fluoropolyethers (PFPAEs) in properties useful for vacuum applications in which low temperature fluidity and low volatility are important properties. It is half the density of PFPAE and exhibits inhibitable oxidation properties similar to other hydrocarbons. The pressure-viscosity coefficient is similar to those of PAOs and PFPAEs.