芥子气纯度测定不确定度分析与评定

采用酸碱滴定法测定芥子气纯度,对测量结果的不确定度进行评定。分析了测定过程中不确定度来源,包括滴定剂的标定、消耗滴定剂体积、样品称量等引入的不确定度及其计算方法,最后合成得到标准不确定度。当芥子气纯度测定结果为94.78%时,扩展不确定度为0.34%(k=2)。实验结果表明,样品称量引入的不确定度对测量结果的影响最大。     

Additives for the reduction of sulfur in FCC gasoline

Sulfur reduction ability of alumina supported zinc, gallium and zinc-gallium additives for fluid catalytic cracking catalysts was evaluated in a micro-activity test unit (MAT). Gallium/alumina showed the highest sulfur reduction of 31%, but the cracking activity of the catalyst was decreased. Zinc-gallium/alumina reduced sulfur in 24 wt.% without decreasing the base catalyst activity.     

含硫液体烃燃料水蒸气重整制氢I．Pt／Ce0．8Gd0．2O1．9催化剂的制备、表征和抗硫性能

以柠檬酸溶胶-凝胶法合成的具有萤石结构的Ce0.8Gd0.2O1.9（CGO）复合氧化物为载体，用初湿浸润法制备了负载型Pt催化剂．纯异辛烷的重整反应结果显示，600和800℃焙烧的催化剂达到了热力学平衡转化，1000℃焙烧会导致Pt的聚集和氧化物的严重烧结，因而催化剂活性较差．抗硫测试表明，800℃焙烧的催化剂抗硫性能最好，在300μg／g硫存在下，100h内异辛烷均接近完全转化；在500μg／g硫存在下催化剂仍表现出良好抗硫性能．程序升温还原和X射线分析结果显示．800℃焙烧时Pt与CGO载体间的相互作用最强，同时催化剂具有良好的热稳定性，这是催化剂具有抗硫性能并且抗硫作用持久的根本原因．反应条件下噻吩硫完全转化成H2S，硫的转化可能是通过氧化-还原机理进行的．     

DeNOx催化剂FeZSM-5/Raney Fe的制备

用原位晶化法合成了FeZSM-5/RFe(RFeRaney Fe)催化剂. 合成液的组成为5Na2O*100SiO2*10TPABr*7 000H2O,pH＞11.5. 合成液中不含Al,ZSM-5分子筛的骨架Al只来源于Raney Fe的表面. 此法提高了ZSM-5分子筛中骨架Al的稳定性和分子筛上Fe离子的负载量. FeZSM-5/RFe用作DeNOx催化剂时具有较高的活性和水热稳定性.     

π-facial interactions between Cl and [S4N3]. X-ray crystal structure of [S4N3]Cl

The X-ray structure of [S₄N₃]Cl reveals three independent molecules, which all display π-facial interactions between the Cl⁻ and the pseudo-aromatic [S₄N₃]⁺ rings to produce a structure containing “inverse sandwich” systems.     

Synthesis of a new polyfluorinated vinylogue of tetrathiafulvalene through 1,3-dipolar cycloaddition of ethyl beta-bromoperfluorodithiocrotonate with dimethyl acetylenedicarboxylate

The ethyl ester of beta-bromoperfluorodithiocrotonic acid reacts with dimethyl acetylenedicarboxylate to give 1,4-difluoro-2,3-bis(trifluoromethyl)-but-2-ene-1,4-diylidene-2,2'-bis(4',5'-dicarbomethoxy-1',3'-dithiole) (4), a new type of vinylogue of tetrathiafulvalene. The thermal transformations of this compound lead, depending on the temperature, to the formation of the cyclization products: 11,14-difluoro-2,3,8,9-tetra(carbomethoxy)-12,13-bis(trifluoromethyl)-1,4,7,10-tetrathiadispiro[4.0.4.4]tetradeca-2,8,11,13-tetraene (8) or 5,8-difluoro-6,7-bis(trifluoromethyl)-2,3-bis(carboxymethyl)-1,4-benzodithiine (11).     

Blood cell separation using crosslinkable copolymers containing N,N‐dimethylacrylamide

Amphiphilic copolymers using hydrophilic N,N‐dimethylacrylamide (DMA), hydrophobic methyl methacrylate (MMA) and a crosslinkable monomer, 3‐methacryloyloxypropyl trimethoxysilane (MTSi), were synthesized and evaluated as coating materials for leukocyte removal filters for whole blood. When filters composed of non‐woven fabrics were coated with crosslinked synthesized copolymers, the elution ratios of the copolymers to water were adequately low because of the crosslinking with trimethoxysilane groups of MTSi units in the copolymers. Filters coated with crosslinked poly(DMA‐co‐MTSi) having a 0.96 mole fraction of DMA units showed a 0.35 ± 0.44% platelet permeation ratio and a logarithmic reduction of 4.0 ± 0.68 for leukocytes. On the other hand, an increase in the content of MMA units in the DMA‐containing copolymers improved the permeation ratio of the platelets dramatically. Filters coated with crosslinked poly(DMA‐co‐MMA‐co‐MTSi) containing a 0.39 mole fraction of MMA units and a 0.58 mole fraction of DMA units showed an 86 ± 3.0% platelet permeation ratio and a logarithmic reduction of 2.1 ± 1.2 for leukocytes. This indicates that an adequate content of hydrophobic monomer units, such as MMA units, is necessary for effective platelet permeation. Copyright © 2007 John Wiley & Sons, Ltd.     

A novel synthesis of organic diselenapolysulfides

A family of organic polychalcogenides with a common structure of RSeS_xSeR (with x=1, 2, 3 and R=CH₃, Ph, PhCH₂, O₂NC₆H₄CH₂) as well as cyclic 5,5-dimethyl-1,2-dithia-3,7-diselenacycloheptane were synthesized in good yield and high purity from the reaction of Ph₃CS_xCl with corresponding diselenides in chloroform at room temperature. Mechanistic aspects of the insertion involving the formation of an intermediate (RSeS_xCPh₃) are discussed.     

Polysulfide Coordination Clusters of the Lanthanides

The reaction of [(DippForm)₂Ln(thf)₂] with an excess of elemental sulfur in toluene resulted in the formation of the trinuclear polysulfide coordination clusters [(DippForm)₃Ln₃S₁₂] (Ln=Sm, Yb; DippForm=N,N′‐bis(2,6‐diisopropylphenyl)formamidinate). These are the first f element coordination clusters (Ln_nS_x) with a larger polysulfide unit (n and x>2). The formation of the coordination clusters can be rationalized by the reductive cleavage of S₈ with divalent lanthanides.