长链聚酰胺酸的热环化动力学

利用GPC、原位FTIR测定了长链聚酰胺酸PAA(由双酚A二酐与 4 ,4′ 二 (4 胺基苯氧基 )二苯酚制备 )的热环化过程 .结果表明 ,在升温热环化的初始阶段 ,聚合物环化的同时其分子链断裂成酐、胺端基分子链 ,相对数均分子量降低 ,薄膜渐脆 ;随着温度进一步的升高 ,酐、胺端基链又重新链合 ,相对数均分子量回升 ,薄膜重具韧性 ;恒温热环化存在两个明显的阶段 ,初期的快速阶段和后期的慢速阶段 ,表现出动力学中断的现象 .采用两步、一级动力学模型研究热环化并得出相关的动力学参数 (速率常数、活化能、指前因子等 ) .针对恒温热环化 ,建立动力学中断时亚胺化程度与温度的关联式 ,从构象转化与自由体积两个方面对动力学中断现象提出解释 ,并由实验数据得到了该关联式的相关参数     

Synthesis and Characterization of Ion-exchange Sulfonated Poly （ether sulfone）

N,N'-Bis(3-hydroxyphenyl)-1,8,4,5-naphthalenetetracarboxylic bisimide was prepared from the reaction of 1,8,4,5-naphthalenetetrcarboxylic acid dianhydride and 2-aminophenol in N, N-dimethylformamide. Polymerization of this bisimide with 4,4'-difluorodiphenylsulfone and disodium 3,3'-disulfonate4,4'-difluorodiphenylsulfone gave ion-exchange sulfonated poly(ether sulfone). The structure of the title compound was characterized with 1H-NMR and its polymer was characterized with FT-IR.     

水悬浮体系中α,β-环氧酮类化合物的合成研究

在水悬浮体系中使用三氯异氰尿酸/碱氧化体系对α,β-不饱和酮化合物进行环氧化和对烯丙基醇类化合物进行直接氧化-环氧化制备α,β-环氧酮, 考察了表面活性剂、碱等因素对反应的影响. 反应无需有机溶剂, 对于大部分的烯酮和烯丙基醇反应可以在数小时内完成, 产率良好.     

Isomerization and conformational transformations of theN-allyl-N-methylcarbamoyl bridging ligand in the (μ-H)Os3{μ-OCN(Me)CH2CH=CH2}(CO)10 complex

The (μ-H)Os₃{μ-OCN(Me)CH₂CH=CH₂}(CO)₁₀ complex containing an allylic fragment in theN,N-dialkylsubstituted carbamoyl briding ligand was synthesized. The stereo-chemical behavior of this complex in solution was investigated. As follows from the NMR spectral data, the complex undergoes reversible conformational (about the amide C−N bond) and irreversible allylic isomerization. Both conformers were isolated in the solid state by chromatography at a reduced temperature. The allylic isomerization occurs stereospecifically to produce the (μ-H)Os₃{μ-OCN(Me)CH=CHMe}(CO)₁₀ complex with thetrans-oriented olefinic hydrogen atoms. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 158–162, January, 1998.     

Synthesis of 2,6-dimethyl-9-aryl-9-phosphabicyclo[3.3.1]nonanes: their application to asymmetric synthesis of chiral tetrahydroquinolines and relatives

Synthesis of 2,6-dimethyl-9-aryl-9-phosphabicyclo[3.3.1]nonanes from 1,5-cyclooctadiene and their application to asymmetric cyclization leading to chiral tetrahydroquinolines and relatives through palladium-catalyzed allylic alkylation are described.     

Stereoselective synthesis of vinyl sulfones by carbomagnesiation of acetylenic sulfone in the presence of CuCN

Carbomagnesiation of acetylenic sulfone in the presence of catalytic amount of CuCN gave α-sulfonyl vinyl magnesium reagent, which further reacted with aldehydes to afford polysubstituted vinyl sulfones in moderate to good yields.     

DMFC用PES/SPEEK共混阻醇质子交换膜

将磺化聚醚醚酮(SPEEK, 磺化度DS为68.3%)和聚醚砜(PES)两种聚合物共混制得PES/SPEEK共混膜. DSC研究表明两种聚合物之间具有较好的相容性, 因而共混膜均匀致密, 未发生大尺度相分离. PES的混入能有效降低膜的溶胀度及甲醇透过系数. 纯SPEEK 膜40 ℃时在1 mol•L−1甲醇水溶液中溶胀度达到160%, 45 ℃时就完全溶解, 而含30%(w)PES的共混膜在80 ℃时的溶胀度仅有15%. 室温下含20%−30%(w)PES的共混膜的甲醇透过系数为1×10−7 cm2•s−1左右, 比Nafion 115膜的透过系数小一个数量级. 尽管80 ℃下30%(w)PES/SPEEK共混膜的电导率与Nafion 115膜相当, 但由于共混膜的厚度比Nafion 115膜小1/3左右, 膜电阻较小, 因而其电池性能比Nafion 115膜的好.     

Cyclic Oligomers of Phenolphthalein Polyarylene Ether Sulfone （Ketone）： Preparation Through Cyclo-depolymerisation of Corresponding Polymers

Cyclic oligomers of phenolphthalein polyarylene ether sulfone(ketone) were preparedthrough cyclo-depolymerisation of corresponding polymers using CsF as the catalyst in dipolaraprotic solvent DMAc and DMF, and a family of macrocycles containing from dimer up to at leastheptamer were confirmed by GPC, HPLC and MALDI-TOF-MS. The yields of cyclics get ashigh as 86.3% and 87.9% respectively.     

New Chiral N,S-Ligands with Thiophenyl at Benzylic Position. Palladium(II)-catalyzed Enantioselective Allylic Alkylation

Ｃｈｉｒａｌｌｉｇａｎｄｓｐｌａｙａｃｒｕｃｉａｌｒｏｌｅｉｎａｓｙｍｍｅｔｒｉｃｃａｔａｌｙｓｉｓ .Ｔｏｄａｔｅａｖａｒｉｅｔｙｏｆｌｉｇａｎｄｓｈａｖｅｂｅｅｎｓｙｎｔｈｅ ｓｉｚｅｄａｎｄｐｒｏｖｅｄｔｏｂｅｅｆｆｅｃｔｉｖｅ .Ａｍｏｎｇｔｈｅｍｔｈｅｌｉｇａｎｄｓ1ｗｉｔｈｂｏｔｈｃｏｏｒｄｉｎａｔｅａｔｏｍｓａｔｂｅｎｚｅｎｅｒｉｎｇ ｐｏｓｉｔｉｏｎｓｓｈｏｗｇｏｏｄｔｏｅｘｃｅｌｌｅｎｔａｓｙｍｍｅｔｒｉｃｉｎｄｕｃｔｉｏｎｉｎｃａｔａｌｙｔｉｃａｓｙｍｍｅｔｒｉｃｒｅａｃｔｉｏｎｓ …     

Efficient synthesis of 3-substituted 2,3-dihydroquinolin-4-ones using a one-pot sequential multi-catalytic process: Pd-catalyzed allylic amination-thiazolium salt-catalyzed Stetter reaction cascade

We developed an efficient method for the synthesis of 3-substituted 2,3-dihydroquinolin-4-ones using a one-pot sequential multi-catalytic process: Pd-catalyzed allylic amination-thiazolium salt-catalyzed Stetter reaction cascade. Measurement of the initial rate of the developed sequential process revealed a significant increase in the reaction rate of the Stetter reaction in the presence of Pd(OAc)₂ and AcOH·i-Pr₂NEt, the constituents of the first Pd catalysis.