噻吩在镍基非晶态合金上的吸附和脱附

应用静态吸附、动态吸附、程序升温脱附和程序升温还原等实验方法，考察了噻吩在Ni基非晶态合金上的吸附和脱附行为。常温下，噻吩分子首先吸附在清洁的Ni表面，并立刻被活化，发生氢解反应，C-S键断裂，释放出烃类部分，S留在Ni原子上。噻吩可以在Ni基非晶态合金表面发生强度不同的化学吸附。弱化学吸附的噻吩可以脱附；强化学吸附的噻吩不会脱附，而在高温下发生氢解反应。     

过渡金属对Au-Pd/TiO_2-Al_2O_3催化剂加氢脱硫性能的影响

研究了掺杂过渡金属Ru,Ni,Co对Au-Pd/TiO2-Al2O3催化剂催化噻吩加氢脱硫活性的影响,并采用X射线衍射、电感耦合等离子发射光谱、程序升温还原和程序升温脱附等方法对TiO2-Al2O3复合载体、Au-Pd/TiO2-Al2O3和Au-Pd-TM/TiO2-Al2O3(TM表示过渡金属)催化剂进行了表征。实验结果表明,掺杂过渡金属未改变Au-Pd/TiO2-Al2O3催化剂的结构;掺杂Ru或Ni增强了Au-Pd/TiO2-Al2O3催化剂的活性组分与TiO2-Al2O3复合载体的相互作用,降低了反应活化能,提高了催化剂活性组分的分散度和活性比表面积,改善了Au-Pd/TiO2-Al2O催化剂的吸附性能,从而提高了Au-Pd/TiO2-Al2O3催化剂催化噻吩加氢脱硫的活性;而掺杂Co的效果则与之相反。     

Deposition of CoO onto MoO3/Al2O3 hydrodesulfurization catalysts by solvent assisted spreading

Solvent assisted spreading of CoO over monolayer MoO₃/Al₂O₃ catalysts has been studied. CoCO₃ · Co(OH)₂ and CoCO₃ reacted with MoO₃/Al₂O₃ in water slurries. CoO deposition over MoO₃/Al₂O₃ extrudates was followed by EPMA. In the set of eleven MoO₃/Al₂O₃ catalysts, the amount of CoO adsorbed was roughly proportional to the surface area of MoO₃ monolayer. The adsorbed Co species efficiently enhanced the HDS activity.     

Catalyst’s Sulfur Displacement by Thiophene, as Monitored by Exchange of 35S Radiotracer

The isotopic exchange has been studied between catalyst radiosulfur and H₂S, formed in thiophene hydrodesulfurization (HDS) (named S-displace) on alumina supported molybdena, on CoMoO_x, PdMoO_x, PtMoO_x and on silica–alumina supported NiWO_x. S-displace was compared with radiosulfur exchange data between catalyst radiosulfur and gas phase H₂S (S^exc) determined previously. The extent of S^exc was higher than that of the S-displace for Mo, CoMo in and NiW, whereas the extent of S-displace from PdMoO and PtMoO was significantly higher, than that of S^exc. Thiophene HDS product distribution data are discussed in terms of increased C=C hydrogenation and C–C hydrogenolysis activity, explained by increasing H₂S production with longer circulation time of the thiophene/H₂ mixture, The C₁/C₃<1 ratios among C₄-hydrogenolysis products indicate some coke formation. The decrease of thiophene HDS activity is presumably a consequence of increasing site-blocking with the formation of more H₂S and coke with longer duration of thiophene treatment.     

噻吩类导电高聚物的研究进展

噻吩类聚合物是研究较为广泛的功能高分子材料。详述了通过化学氧化聚合法和电化学氧化聚合法所合成的噻吩类导电聚合物的性能和用途,常用的结构与性能表征方法以及噻吩类导电聚合物在光、电、磁等各种领域中的应用。     

一锅法合成3,4-二甲氧基噻吩

以丁二酮和原甲酸甲酯为原料,合成的2,3-二甲氧基丁二烯不经分离,直接与二氯化硫反应,一锅法成功合成了目标产物3,4-二甲氧基噻吩,总产率达60%。用核磁、红外、紫外等波谱鉴定了目标分子的结构。本法具有反应条件温和,后处理简单,产率高等优点。     

基于荧光多元猝灭响应原理膜传感器测定正己烷中的噻吩

用溶胶 凝胶法制备光纤化学传感器测定正己烷中噻吩的浓度 ,在 1 0 .6～ 2 6 5μg/mL浓度范围内与lg(F0 /F) )成线性 ,相关系数为 0 .9984。检出限为 1 0 .6 μg/mL ,该方法的平均回收率为 1 0 5.0± 7.7%。     

The interplay of electronic structure,molecular orientation and charge transport in organic semiconductors: Poly(thiophene) and poly(bithiophene)

Ultrathin films of poly(thiophene) (PT) and poly(bithiophene) (PBT) were prepared by electrochemical route using ionic liquid (BFEE) as medium and electrolyte. Distinct morphologies and electrical properties were observed in these materials. To evaluate its response in photovoltaics, these films were used as active layer in bilayer geometry solar cells with the electron acceptor molecule C₆₀. The best performance was observed for PT films. In order to probe the differences in molecular dynamics and structural order, ultrafast electron dynamics in the low-femtosecond regime was evaluated by resonant Auger spectroscopy using the core–hole clock method at the sulfur K absorption edge. Electron delocalization times for the different polymeric films were derived as a function of the excitation energy. Photoabsorption measurements were conducted and molecular orientation derived. These results corroborated with the morphology found for these films and thus the performance of PT and PBT in the devices, and with the proposed conduction mechanism.     

Chitosan Schiff base as effective corrosion inhibitor for mild steel in acid medium

An environment friendly inhibitor, chitosan thiophene carboxaldehyde Schiff base, was synthesized by a condensation reaction of the carbonyl group of thiophene 2‐carboxaldehyde and free amino groups of chitosan. The chitosan Schiff base was characterized by UV spectroscopy, Fourier transform IR spectroscopy, elemental analysis and thermal analysis. The surface morphology of the Schiff base derivative was examined by SEM. Gravimetric and electrochemical techniques were used to explore the behaviour of the chitosan thiophene derivative as a corrosion inhibitor for mild steel in an acidic environment. The effects of inhibitor concentration, exposure time and temperature were investigated. The chitosan Schiff base showed a good inhibition performance of 92% inhibition efficiency at room temperature for 12 h of immersion in a weight loss experiment. The electrochemical results showed that the chitosan derivative acts as an effective mixed type inhibitor. The adsorption of the inhibitor followed the Temkin isotherm model. SEM and AFM techniques were used to characterize the protective layer formed on the mild steel substrate. © 2016 Society of Chemical Industry