渣油中硫化物的测定方法研究进展

渣油中硫化物的存在对石油加工和石油生产带来很多不利条件,渣油中的主要硫化物为硫醚硫和噻吩硫,总硫与硫醚硫的差值即为噻吩硫。对硫化物定量研究,可以为渣油加工提供理论依据和数据基础。本文概述了渣油中硫醚硫的测定方法,并对各种方法的优缺点进行了讨论,在实际应用中应结合实际条件选择合适的方法对硫化物进行研究。     

A simple and efficient synthesis of new indeno- and naphtho-fused thiophenes using arylthioacetamides

New indeno- and naphtho-fused thiophenes were synthesized from reaction of 2-bromo-1-indanone and 2-bromo-1-tetralone with arylthioacetamides in good yields.     

Palladium‐Catalyzed Highly Regioselective Arylation of Allylamines with Thiophenes and Furans

A palladium‐catalyzed highly regioselective and stereoselective direct arylation of allylamine derivatives with a wide range of thiophenes and furans has been developed. In the presence of palladium(II) acetate [Pd(OAc)₂] catalyst and appropriate oxidants, the coupling reaction proceeded with excellent group compatibility and high efficiency, leading exclusively to γ‐arylated linear (E)‐allylamines. It was found that the choice of solvent, olefin substrate and oxidant had an important influence on reaction efficiency, and the use of sterically demanding N,N‐diprotected allylamines bearing a carbamate moiety is crucial for securing high regioselectivity and stereoslectivity. This method provides a straightforward approach for the efficient synthesis of various γ‐heteroarylated, linear (E)‐allylamines.     

Syntheses and characterisation of electrically conductive and fluorescent poly[3-(ω-bromoalkyl)thiophenes]

A novel series of functionalized polythiophenes incorporating 3-(ω-bromoalkyl) pendants were synthesized by chemical oxidative polymerization using FeCl₃ and characterized using FT-IR, UV–Vis absorption spectroscopy, fluorescence emission spectroscopy, conductivity measurements and thermal analyses. These polymers attained a maximum electrical conductivity between 4.7 and 8.4 S cm⁻¹ upon doping with iodine and have a fluorescence quantum yield of up to 11.1% with respect to quinine sulfate. The influence of the terminal ω-bromine substituent as of the length of the alkyl pendant on electrical conductivity, spectral behavior and thermal stability is discussed.     

Pd(dppf)Cl2催化Suzuki偶联反应合成4-(4-叔丁基苯基)-6-甲基-1,2,3,5-四氢-s-引达省

以Pd(dppf)Cl2为催化剂催化Suzuki偶联反应合成了一种在烯烃聚合中有重要作用的茂金属催化剂配体——4-(4-叔丁基苯基)-6-甲基-1,2,3,5-四氢-s-引达省(Ⅲ),其结构经1HNMR,IR,GC-MS和MS进行了表征。考察了催化剂、添加剂、溶剂的种类及其与反应物的配比等因素对反应的影响,得到的最佳合成工艺条件为:以底物4-溴-6-甲基-1,2,3,5-四氢-s-引达省计,摩尔分数1.5%Pd(dppf)Cl2,4-叔丁基苯硼酸1.1 mol/mol,无水碳酸钾1.5 mol/mol,异丙醇1 000 mL/mol,回流至溴代茚底物转化保持恒定(约需26 h),Ⅲ的收率为82.1%,GC纯度99%。探索出一种以溴代茚类化合物为底物合成联芳基茚类化合物的方法,有效控制了合成过程中"双键移位"副产物的产生。     

Unexpected synthesis of novel O-ethyl-P-aryl-N-(thiophen-2-yl) phosphonamidothioates from ethyl 2-aminothiophene- 3-carboxylates and Lawesson's reagent

The reaction of ethyl 2-aminothiophene-3-carboxylates with a stoichiometric amount of Lawesson's reagent (LR) gave novel O-ethyl-P-aryl-N-(thiophen-2-yl) phosphonamidothioate derivatives rather than the expected thienothiazaphosphorines. A possible reaction mechanism, involving a carbonyl sulfide extrusion, is proposed.     

A Further Decrease in the Catalyst Loading for the Palladium‐Catalyzed Direct Intramolecular Arylation of Amides and Sulfonamides

The direct arylation of N‐substituted o‐bromobenzanilides and benzenesulfonamides via C H bond functionalization has been developed using very low catalyst loadings. This novel cost‐effective and more sustainable method relies on a PCN‐type palladium pincer complex as a highly active palladium source, providing a general and efficient access to phenanthridinones, biaryl sultams and related heterocyclic systems. The beneficial effect of water as cosolvent has been observed in this process, which is not seriously influenced by electronic effects at the arene moieties or sterically demanding substituents at the amide or sulfonamide nitrogen. In addition, a number of experiments (kinetic plot, poisoning assays, TEM, ESI) have been performed in order to understand the role of the employed palladium complex in this reaction.

     

Soluble Phenanthrenyl‐Imidazole‐Presenting Regioregular Poly(3‐octylthiophene) Copolymers Having Tunable Bandgaps for Solar Cell Applications

We have used Grignard metathesis polymerization to successfully synthesize a series of regioregular polythiophene copolymers that contain electron‐withdrawing and conjugated phenanthrenyl‐imidazole moieties as side chains. The introduction of the phenanthrenyl‐imidazole moieties onto the side chains of the regioregular polythiophenes increased their conjugation lengths and thermal stabilities and altered their bandgap structures. The bandgap energies, determined from the onset of optical absorption, could be tuned from 1.89 eV to 1.77 eV by controlling the number of phenanthrenyl‐imidazole moieties in the copolymers. Moreover, the observed quenching in the photoluminescence of these copolymers increases with the number of phenanthrenyl‐imidazole moieties in the copolymers, owing to the fast deactivation of the excited state by the electron‐transfer reaction. Both the lowered bandgap and fast charge transfer contribute to the much higher external quantum efficiency of the poly(3‐octylthiophene)‐side‐chain‐tethered phenanthrenyl‐imidazole than that of pure poly(3‐octylthiophene), leading to much higher short circuit current density. In particular, the short circuit current densities of the device containing the copolymer having 80 mol % phenanthrenyl‐imidazole, P82 , improved to 14.2 mA cm^–2 from 8.7 mA cm^–2 for the device of pure poly(3‐octylthiophene), P00 , an increase of 62 %. In addition, the maximum power conversion efficiency improves to 2.80 % for P82 from 1.22 % for P00 (pure P3OT ). Therefore, these results indicate that our polymers are promising polymer photovoltaic materials.     

A Facile and Convenient Synthesis of some Novel Hydrazones, Schiff's Base and Pyrazoles Incorporating Thieno[2,3-b]thiophenes

A facile and convenient synthesis of some novel hydrazones, schiff's base and pyrazoles from thieno[2,3-b]thiophene derivatives 1 have been achieved in high yields assisted by microwave and classical methods. The structures of all the title compounds have been elucidated by elemental analysis, IR, MS, (1)H-NMR and (13)C-NMR. Generally, these findings represent a new class of sulfur and nitrogen moieties that should also be of interest as new materials.     

Synthesis and Properties of Branched Oligo(2‐thienyl)‐ and Oligo(2,2′‐bithien‐5‐yl)‐Substituted Pyridine Derivatives

Starting from easily accessible precursors we describe the preparation of a series of branched oligo(2‐thienyl)‐ and oligo(2,2′‐bithienyl)‐substituted pyridine derivatives. With palladium‐catalyzed cross‐coupling reactions of pyridyl nonaflates/triflates as key steps we synthesized 2,6‐di(2‐thienyl)pyridines bridged by thiophene or benzene rings. By selective bromination of 2,6‐di(2‐thienyl)pyridine and 2,4,6‐tri(2‐thienyl)pyridine and subsequent coupling reactions an access to oligo(2,2′‐bithien‐5‐yl)‐substituted pyridine derivatives was gained. The constitution and solid state conformation of 2,6‐bis(2,2’‐bithien‐5‐yl)pyridine was determined by X‐ray analysis. This series of new pyridine‐thiophene conjugates was systematically investigated by UV/vis spectroscopy. Large Stokes shifts in the neutral and protonated form were observed. The electrochemical oxidation of two typical compounds was studied, however, these oxidations were irreversible forming a polymeric film at the anode. As a selected example, a thiophene‐bridged 2,6‐di(2‐thienyl)pyridine derivative was also investigated by scanning tunneling microscopy showing an interesting self‐assembly into a highly ordered monolayer on highly oriented pyrolytic graphite.