Removal of sulfur components from low sulfur gasoline using copper exchanged zeolite Y at ambient temperature

Copper-exchanged zeolite Y has been shown to be an effective material for removal of a variety of sulfur species from hydrocarbon streams, and both monovalent (Cu(I)) and divalent (Cu(II)Y) materials have been claimed to be effective. In this work we discuss experiments aimed at providing a direct performance comparison between the two copper-containing materials. Cu(I)Y zeolite is somewhat more effective than Cu(II)Y in removing thiophene from various fuel blends. Capacity of both materials for thiophene diminishes markedly when aromatics and/or olefins are present, and Cu(I)Y immediately turns dark on exposure to such feeds. Both materials demonstrate ability to convert thiols to disulfides at ambient temperature.     

The role of carbazole in organic light-emitting devices

New organic oligomers and polymers based on the carbazole molecule are explored for possible applications in light-emitting devices. In one case, (butyl- or octyl-) carbazole dimers and poly(N-butyl-3,6-carbazolylene) polymer were used as the hole-transporting and light-emitting layer in multilayer light-emitting diodes (LEDs). These devices yielded bright blue light (as much as about 6000 cd m⁻²) with high external quantum (about 10%) and luminance efficiencies (about 2 lm W⁻¹). The other case involved (3-octylthiophene]-[bis-(N-ethyl or octyl carbazolylene)]) multiblock copolymers as the active emitting layer in single-layer LEDs. Color tuning was achieved in these devices by changing the number of monomer units contained in the thiophene chain. We also observed an increase of the external quantum efficiency in diodes based on the copolymers with short thiophene segments that we attributed to a more balanced charge injection.     

CVD preparation of alumina-supported niobium nitride and its activity for thiophene hydrodesulfurization

Niobium nitride was synthesized on a Si(400) substrate and a γ-alumina pellet using a CVD method with a stream of NbCl₅/Ar, NH₃, and H₂ gases at 723–973 K under reduced pressure. The composition and surface properties of the deposited niobium nitride were analyzed using XRD and XPS measurements. The activity of alumina-supported niobium nitrides for the hydrodesulfurization (HDS) of thiophene at 673 K and atmospheric pressure was determined. The alumina had a surface area of 177 m² g⁻¹ and the alumina-supported niobium nitride catalyst had surface areas of 179–190 m² g⁻¹. Although the catalysts had low activity in the initial stages, the activity increased after 200–300 min started to about three times the initial activities. XPS analysis indicated that the activity of the niobium nitride catalysts was decreased by sulfur accumulation on the surface and nitrogen released from niobium nitride. The relationship between the surface properties of the niobium nitride catalysts and the activities for thiophene HDS is discussed.     

Electrosynthesises and characterizations of copolymers based on thiophene and 3,4-ethylenedioxythiophene in boron trifluoride diethyl etherate

Copolymers based on thiophene and 3,4-ethylenedioxythiophene (EDOT) are successfully electrodeposited on ITO electrodes in boron trifluoride diethyl etherate (BFEE). Cyclic voltammograms (CVs), Fourier transition infrared spectra (FTIR), Scanning electron microscopy (SEM), and spectroelectrochemical analysis are used to characterize the structure and properties of the resultant copolymers. Spectroelectrochemistry indicates that electrochromic properties of the copolymer films can be tuned by controlling the feed ratio of thiophene/EDOT. The copolymer prepared with thiophene/EDOT feed ratio at 2/1 presents a more negative π–π* transition at 469 nm in comparison with the homopolymers and the bandgap is calculated as 1.80 eV by the onset wavelength. Furthermore, multicolor electrochromism (brown, yellow brown, gray yellow, and gray blue) can be achieved by this copolymer. The copolymer film shows optical contrast of 29% at 767 nm with a response time of 2.6 s and reasonable electrochemical stability, which retains 77.8% of its original electroactivity after 1000 cycles.     

Effect of the number of thiophene rings in polymers with 2,1,3-benzooxadiazole core on the photovoltaic properties

A series of polymers, poly{5,6-bis(decyloxy)-4-(thiophen-2-yl)benzo[c][1,2,5]oxadiazole} (1T-BO20), poly{4-(2,2′-bithiophen-5-yl)-5,6-bis(decyloxy)benzo[c][1,2,5]oxadiazole} (2T-BO20), poly{4-(2,2′-bithiophen-5-yl)-5,6-bis(decyloxy)-7-(thiophen-2-yl)benzo[c][1,2,5]oxadiazole} (3T-BO20) containing 2,1,3-benzooxadiazole derivative and different thiophene rings are synthesized. Effect of the number of thiophene rings on the optical, electrochemical and photovoltaic properties of the polymers is investigated. The maximum absorption wavelength and the optical band gap of the polymers are almost the same, indicating the polymers exhibit similar intramolecular charge transfer effect. The HOMO levels are in the order of 1T-BO20 (−5.60 eV) < 2T-BO20 (−5.45 eV) < 3T-BO20 (−5.36 eV), revealing that the HOMO level of the polymers are dependent of number of thiophene ring in the back bone. Under the illumination of AM 1.5G, 100 mW/cm², the power conversion efficiency (PCE) of PSCs based on these polymers increases in the order of 1T-BO20 (1.66%), 2T-BO20 (1.71%) and 3T-BO20 (1.92%). Besides, we find that the efficiency of PSCs showed very different responses by the addition of DIO as a processing additive. The devices based on 1T-BO20 and 2T-BO20 with DIO exhibit an enhancement of PCE from 1.66% to 3.65% and from 1.71% to 2.40%, respectively, whereas PCE of the device based on 3T-BO20 with DIO decreased from 1.92% to 1.76%.     

苯－噻吩－二甲基甲酰胺大沸点差体系的汽液平衡

用鼓泡平衡釜在不同温度下测定了苯－噻吩－ＤＭＦ（Ｎ，Ｎ－Ｄｉｍｅｔｈｙｌｆｏｒｍａｍｉｄｅ，二甲基甲酰胺）体系的二元和三元体系的汽液平衡（ＶＬＥ）数据，所测数据均通过热力学一致性检验，并用多种模型作了关联，其结果令人满意。根据Ｃｏｎｄｅｒ和Ｐｕｒｎｅｌｌ提出的有限浓度普遍化保留理论导出了有限稀释活度系数工作方程，用色谱仪测定了苯－ＤＭＦ和噻吩－ＤＭＦ两个二元体系在稀浓度区的活度系数，结果证明在全浓度范围内Ｗｉｌｓｏｎ模型对本研究体系是完全适用的。     

PEDT导电聚合物气敏特性研究

采用化学聚合法制备了导电聚合物3,4-乙烯二氧噻吩膜,利用扫描电子显微镜和傅里叶变换红外光谱法对薄膜的光学成分及形貌进行了分析。采用叉指电极结构研制出了3,4-乙烯二氧噻吩薄膜气体传感器,研究了3,4-乙烯二氧噻吩薄膜气体传感器对有毒气体NO2和NH3的敏感特性以及其自身的温度特性。结果发现,3,4-乙烯二氧噻吩薄膜气体传感器对低浓度的NO2和NH3都具有很好的敏感特性。该文还对3,4-乙烯二氧噻吩薄膜对NO2和NH3两种气体的敏感机理进行了详细的讨论。     

改性分子筛吸附脱硫

以ZSM-5、Y型、MCM-41分子筛为载体,采用离子交换法制备了一系列用于汽油脱硫的负载金属离子的改性分子筛吸附剂。对不同的吸附剂作了X-射线衍射和比表面积分析,考察了静态吸附条件对其脱硫性能的影响。结果表明,不同吸附剂对噻吩的吸附效果不同,CuY的效果较为明显,并得出适宜的吸附条件:常温,常压,剂油质量比为0.15。通过对再生前后吸附剂CuY的变化分析,对吸附脱硫的机理进行了探讨。     

噻吩和烃类在Cu（Ⅰ）Y分子筛上的吸附和扩散

通过液相离子交换法制备出Cu（Ⅰ）Y分子筛,并采用频率响应技术研究噻吩、苯、1-辛烯和正辛烷在Cu（Ⅰ）Y分子筛上的吸附和扩散。结果显示,噻吩和正辛烷在Cu（Ⅰ）Y分子筛上的传质过程的速控步骤为吸附过程,并存在两种不同的吸附过程,结合吸附等温线发现噻吩和Cu（Ⅰ）Y分子筛的作用力明显强于正辛烷的。苯在Cu（Ⅰ）Y分子筛上的传质过程的速控步骤为扩散过程,结合扩散系数,表明苯在Cu（Ⅰ）Y分子筛上的扩散为单一扩散过程。