Synthesis of substituted polymethylenes by radical polymerization of alkyl N,N-dialkylfumaramates and maleamates: Relative reactivity of the isomers

Bulk polymerization of alkyl N,N-dialkylfumaramates (FAE) and maleamates (MAE) was performed in the presence of a radical initiator. It has been found that FAE is more reactive than MAE when the reactivity of the two geometrical isomers was compared for their homo- and copolymerizations. From investigation on the effect of ester and N-substituents of these monomers, it has been found that the isopropyl ester shows a higher reactivity than the methyl ester and that N-ethyl and n-butyl substitution gives polymers with high molecular weight of more than several thousands. The resulting substituted polymethylenes from FAE and MAE were characterized and compared with each other. The isomerization of MAE to FAE with morpholine as an isomerization catalyst and monomer-isomerization radical polymerization were also investigated.     

胺型键合反相固定相的制备及评价

首次将一种新型硅烷偶联剂--β-（3，4-环氧环已基）乙基三甲氧基硅烷（β-ECTS）与辛胺反应，然后再键合到硅胶上，得到了胺型键合固定相，并用元素分析、^13C固体核磁共振、红外光谱进行了表征。以甲醇和水为二元流动相，用包括碱性、酸性和中性有机化合物在内的混合物对该固定相进行评价，并考察了该填料的适用pH范围及水解稳定性。结果表明，该固定相具有较好的色谱性能，且在pH=2-8之间稳定性能良好，可有效地用于碱性化合物的分析分离。     

Synthesis of Arylidene Derivatives of 1-Aryl-3H-pyrrol-2-ones

The aminolysis of 5-aryl-3-arylidene-3H-furan-2-ones by the action of aromatic amines leads to the formation of substituted amides of 4-oxo acids, the subsequent azacyclization of which in the presence of acetic anhydride leads to the formation of 1,5-diaryl-substituted 3-arylidene-3H-pyrrol-2-ones. The mechanism of the occurring and alternative transformations is discussed.     

The derivatization of fatty acids by (chloro)alkyl chloroformates in non-aqueous and aqueous media for GC analysis

Fatty acids can be conveniently derivatized in less than one minute with (chloro)alkyl chloroformates such as methyl chloroformate, 2-chloroethyl chloroformate and 2,2,2-trichloroethyl chloroformate. 2,2,2-Trichloroethyl chloroformate is the most reactive reagent, and yields a reaction product which can be sensitively detected by GC ECD (detection limit 50 ng/ml, i.e. 25 pg/injection, for C⁸, C¹⁰, and C¹² acids). In non-aqueous media 3-picoline, N-methylpiperidine, and dimethylaminopyridine show catalytic activity comparable with that of pyridine and can, therefore, replace it. N-methylpiperidine is the best basic catalyst in aqueous media (i.e. media containing up to 40 % water).     

Synthesis and structures of silicon-, germanium- and tin-containing tungsten imido alkyl complexes (ArN)2W(CH2EMe3)2 (E = Si, Ge, Sn)

The novel silicon-, germanium- and tin-containing imido alkyl complexes of tungsten of the type (ArN)₂W(CH₂EMe₃)₂ (; E = Si (1), Ge (2), Sn (3)) have been prepared by the reactions of (ArN)₂WCl₂(dme) (dme = 1,2-dimethoxyethane) with heteroelement-containing alkyllithium or Grignard reagents Me₃ECH₂Li (E = Si, Ge), Me₃ECH₂MgCl (E = Ge, Sn). The title compounds were isolated in high yields as crystalline solids and characterized by elemental analysis, IR, ¹H, ¹³C, ²⁹Si and ¹¹⁹Sn NMR spectroscopy and X-ray diffraction studies. The geometry of the W atoms in the compounds can be described as a distorted tetrahedron.     

氯代烷烃、硫粉和氢亚磷酸酯一步合成S-烷基硫磷酸酯

S-苄基硫磷酸酯和S-烷基硫磷酸酯在农药中有着重要的应用。 本文发展了一种无需催化剂,仅在碱作用下,氯代烷烃、硫粉以及氢亚磷酸酯三组份一步生成S-烷基硫磷酸酯的绿色经济方法,该反应可以在一步反应中同时构建磷—硫键和碳—硫键。 以苄氯及衍生物、硫粉、氢亚磷酸酯在碳酸铯的促进下,室温反应,共合成了17个S-苄基硫磷酸酯,产率为70%~99%。 同时,实现了脂肪链的氯代烃、硫粉和氢亚磷酸酯的反应,在三乙胺的促进下,在空气中60 ℃反应,共合成了13个S-烷基硫磷酸酯,产率为45%~93%。 本方法在合成上和工业上将具有较好的应用前景。     

Stereo- and regioselective synthesis of 1,3-diaryl-3-chloro-1-propanols via the reaction of aryl aldehydes with styrene and (E)-β-methylstyrene

Reactions of aryl aldehydes with styrene and (E)-β-methylstyrene in the presence of phenylboron dichloride regioselectively generate 1,3-diaryl-3-chloro-1-propanols and 1,3-diaryl-3-chloro-2-methyl-1-propanols in good to excellent yields with high stereoselectivity.     

Oxidation of aromatic hydrocarbons with oxygen in a radiofrequency plasma

The reactions of three aromatic hydrocarbons, benzene, toluene, and styrene, with oxygen in a radiofrequency (r) plasma were investigated. Benzene was oxidized to yield phenol as a single volatile organic product. Similarly, toluene gave the ring oxidation products, cresols, as well as considerable amounts of methyl oxidation products, consisting mainly of benzaldehyde and benzyl alcohol. In contrast, the oxidation of styrene took place predominantly on the olefinic double bond to produce styrene oxide On basis of the products and effects of reaction variables, r power and flow rates of hydrocarbons and oxygen, on the reaction rate, the oxidation mechanism was discussed, particularly focusing on the intermediate species responsible for the formation of major products.     

Calculation of the thermondynamic values of alkylthiazoles from the Kovats retention indices on the basis of the non-linear additivity principle

Summary Retention indices and their energy equivalents were determined for ten alkylthiazoles analysed on the stationary phases Apiezon L, Triton X-305 and Carbowax 1000. It was found that the energy contributions of identical alkyl groups to the partial molar free energy of sorption of a molecule are not equivalent. Smaller energy contribututions are due to the α-position of alkyl groups with respect to the heteroatoms in the thiazole ring (α-effect). This effect was most pronounced for 2-alkylthiazoles. Higher sorption energies were found for dimethylthiazoles with two methylgroups in a vicinal position. The retention indices were predicted for ten other di- and tri-substituted methyl, ethyl and propyl thiazoles on the basis of the so-called α- and ortho-effects. The predicted values are in good agreement with the experimentally determined values. Dedicated to Prof. Dr. E. sz. Kováts (Ecole Polytechnique Fédérale de Lausanne) on the occasion of his sixtieth birthday.     

烷基在针状焦形成中的作用

采用煤焦油沥青的甲苯可溶物和废聚苯乙烯共碳化制备针状焦,考察了中间相沥青中烷基含量对针状焦性能的影响。结果表明,通过添加废聚苯乙烯共碳化,中间相沥青中烷基的质量分数从12.0%增加到33.3%,可以制备出热膨胀系数更低、光学各向异性排列更好的针状焦。代表光学各向异性指数的两个量,在光学结构单元中,平行于热膨胀系数方向的轴向分矢量平均长度和光学结构单元的矢量平均长度,分别从20.8μm 和23.4μm增加到28.4μm和28.8μm,热膨胀系数从0.8×10^-6 /K降低到0.1×10^-6 /K。针状焦形成过程中中间相沥青的烷基含量增加使体系黏度降低,有利于光学各向异性相的融并和定向排列。烷基的增多在固化阶段产生足量的气体,在向外逸出过程中使融并中间相的芳香平面大分子沿轴向排列的更为规整。