微米级PSt,P(St/MAA)磁性高分子微球的合成Ⅰ. 温度、引发剂、介质极性、稳定剂量的影响

以Fe3O4为核,采用分散聚合法,合成了粒径为0．5－2．0μm、单分散性好、磁含量可达10％的PSt、P（St/MAA)磁性高分子微球。讨论了温度、引发剂、分散介质、稳定剂等因素对反应结果的影响。对所得磁性微球的外观形态、磁响应性进行了表征。     

等离子体引发原位聚合制备凹凸棒土/聚苯乙烯纳米复合物

用阳离子表面活性剂处理凹凸棒土（Attapulgite),通过超声分散的方法将其均匀分散到苯乙烯单体中,并采用等离子体引发的方法制备出凹凸棒土／聚苯乙烯纳米复合物。通过透射电子显微镜（TEM）和X－射线衍射（XRD）观察了凹凸棒土及其纳米复合物的微观结构。对复合物的GPC测试表明,采用等离子体引发聚合反应可以显著提高树脂的分子量。XRD结果表明聚苯乙烯不是嵌入到凹凸棒土的层间,而是通过离子吸附接枝在凹凸棒土的棒状晶束上。     

Indium (III) Tribromide : An Excellent Catalyst for Biginelli Reaction

A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy- carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of β-keto ester, aldehydes and urea through improved Biginelli reaction.     

盐卤硼酸盐化学(非汉字字符)——MgO·nB_2O_3-18%MgCl_2-H_2O过饱和溶液20℃结晶动力学

用结晶动力学方法对不同摩尔比的 Mg O/B2 O3在摩尔分数为 1 8% Mg Cl2 -H2 O中的过饱和溶液在2 0℃的结晶动力学过程进行了研究 .n(Mg O) /n(B2 O3) =1 /1和 1 /1 .5时分别结晶析出 2 Mg O· 2 B2 O3·Mg Cl2 · 1 4H2 O和 2 Mg O· 3 B2 O3· 1 5 H2 O(多水硼镁石 ) .n(Mg O) /n(B2 O3) =1 /2时依次结晶析出 Mg O·3 B2 O3· 7.5 H2 O,Mg O· 2 B2 O3· 9H2 O和 2 Mg O· 3 B2 O3· 1 5 H2 O(多水硼镁石 ) 3种固相 .n(Mg O) /n(B2 O3)=1 /3时结晶析出不同结晶水的六硼酸镁 Mg O· 3 B2 O3· 7H2 O和 Mg O· 3 B2 O3· 7.5 H2 O.析出固相采用X射线粉末衍射、红外光谱和热分析进行物相鉴定 .拟合并给出结晶动力学方程 ,同时对水合镁硼酸盐的结晶反应机理进行了探讨     

First Synthesis of Mosquito Larvicidal Butenolides I and II

ＩｎｔｒｏｄｕｃｔｉｏｎＶｅｒｙｒｅｃｅｎｔｌｙ ,ｔｗｏｎｅｗｍｏｓｑｕｉｔｏｌａｒｖｉｃｉｄａｌｂｕｔｅｎｏ ｌｉｄｅｓＩ (1)ａｎｄＩＩ (2 )ｗｅｒｅｉｓｏｌａｔｅｄｂｙＫａｒｕｎａｒａｔｎｅｅｔａｌ.1ｆｒｏｍｔｈｅｌｅａｖｅｓｏｆａｌｌｔｈｒｅｅｓｐｅｃｉｅｓｏｆＨｏｒｔｏｎｉａ (ｆａｍ ｉｌｙＭｏｎｉｍｉａｃｅａｅ) (Ｈ .ａｎｇｕｓｔｉｆｏｌｉａ ,Ｈ .ｆｌｏｒｉｂｕｎｄａａｎｄＨ .ｏｖａｌｉｆｏｌｉａ) .Ｂｏｔｈｂｕｔｅｎｏｌｉｄｅｓｅｘｈｉｂｉｔｅｄｍｏｓｑｕｉｔｏｌａｒ ｖｉｃｉｄａｌａｃｔ…     

PPV Polymerization through the Gilch Route: Diradical Character of Monomers

Despite various studies on the polymerization of poly(p‐phenylene vinylene) (PPV) through different precursor routes, detailed mechanistic knowledge on the individual reaction steps and intermediates is still incomplete. The present study aims to gain more insight into the radical polymerization of PPV through the Gilch route. The initial steps of the polymerization involve the formation of a p‐quinodimethane intermediate, which spontaneously self‐initiates through a dimerization process leading to the formation of diradical species; chain propagation ensues on both sides of the diradical or chain termination occurs by the formation of side products, such as [2.2]paracyclophanes. Furthermore, different p‐quinodimethane systems were assessed with respect to the size of their aromatic core as well as the presence of heteroatoms in/on the conjugated system. The nature of the aromatic core and the specific substituents alter the electronic structure of the p‐quinodimethane monomers, affecting the mechanism of polymerization. The diradical character of the monomers has been investigated with several advanced methodologies, such as spin‐projected UHF, CASSCF, CASPT2, and DMRG calculations. It was shown that larger aromatic cores led to a higher diradical character in the monomers, which in turn is proposed to cause rapid initiation.     

Olefin Polymerization Catalyzed by Double‐Decker Dipalladium Complexes: Low Branched Poly(α‐Olefin)s by Selective Insertion of the Monomer Molecule

Dipalladium complexes of a cyclic bis(diimine) ligand with a double‐decker structure catalyze polymerization of ethylene and α‐olefins and copolymerization of ethylene with 1‐hexene. The polymerization of 1‐hexene yields a polymer that is mainly composed of the hexamethylene unit formed by 2,1‐insertion of the monomer into the palladium–carbon bond, followed by chain‐walking (6,1‐insertion). The polymerization of 4‐methyl‐1‐pentene proceeds by 2,1‐insertion with a selectivity of 92–97 %, and affords the polymer with methyl and 2‐methylhexyl branches. 2,1‐Insertion occurs selectively in all of the polymerization reactions of α‐olefins catalyzed by the dipalladium complexes. Ethylene polymerization with the catalyst at 100 °C lasts over 24 h, whereas the monopalladium–diimine catalyst loses its activity within 8 h at 60 °C. Polyethylene obtained by the dipalladium catalyst is less‐branched and has a higher molecular weight compared to that of the monopalladium catalyst under the same conditions. Copolymerization of ethylene with 1‐hexene affords solid products with melting points and molecular weights that vary depending on the polymerization time, suggesting formation of a block and/or gradient copolymer.     

Neutral and cationic alkylmanganese(II) complexes containing 2,6-bisiminopyridine ligands

Manganese alkyl complexes stabilised by 2,6-bis(N,N'-2,6-diisopropyl-phenyl)acetaldiminopyridine ((iPr)BIP) have been selectively prepared by reacting suitable alkylmanganese(II) precursors, such as homoleptic dialkyls [(MnR(2))(n)] or the corresponding THF adducts [{MnR(2)(thf)}(2)] with the mentioned ligand. For R=CH(2)CMe(2)Ph or CH(2)Ph, formally Mn(I) derivatives are produced, in which one of the two R groups migrates to the 4-position of the central pyridine ring in the (iPr)BIP ligand. In contrast, a true dialkyl complex [MnR(2)((iPr)BIP)] can be isolated for R=CH(2)SiMe(3). In solution, this compound slowly evolves to the corresponding Mn(I) monoalkyl derivative. A detailed study of this reaction provides insights on its mechanism, showing that it proceeds through successive alkyl migrations, followed by spontaneous dehydrogenation. Protonation of [Mn(CH(2)SiMe(3))(2)((iPr)BIP)] with the pyridinium salt [H(Py)(2)][BAr'(4)] (Ar'=3,5-C(6)H(3)(CF(3))(2)) leads to the cationic species [Mn(CH(2)SiMe(3))(Py)((iPr)BIP)](+). Alternatively, the same complex can be produced by reaction of the pyridine complex [{Mn(CH(2)SiMe(3))(2)(Py)}(2)] with the protonated ligand salt [H(iPr)BIP](+)[BAr'(4)](-). This last reaction allows the synthesis of analogous cationic alkylmanganese(II) derivatives, when precursors of type [MnR(2)((iPr)BIP)] are not available. Treatment of these neutral and cationic (iPr)BIP alkylmanganese derivatives with a range of typical co-catalysts (modified methylaluminoxane (MMAO), B(C(6)F(5))(3), trimethyl or triisobutylaluminum) does not lead to active ethylene polymerisation catalysts.     

Prediction of aqueous solubilities of solid carboxylic acids with COSMO-RS

The methodology for the prediction of aqueous solubilities of solid organic compounds, and their temperature dependence, based on the Conductor-like Screening Model for Real Solvents (COSMO-RS/COSMOtherm) procedure, is presented and evaluated. The predictive capability of the quantum chemistry based program and the applied methodology was tested on the most common solid carboxylic acids. From the temperature dependence of the solubilities, the mean apparent enthalpies of solution were derived. The results obtained for a set of 27 carboxylic acids, consisting of aromatic carboxylic acids, dicarboxylic acids, as well as hydroxycarboxylic acids, are in good agreement with the experimental solubility data and their dependence with the temperature. The mean apparent enthalpies of solution, although of the same order of magnitude of the experimentally values, seem to be systematically underestimated.     

多元电解质溶液表面张力的新型预测方程

将半理想溶液理论和Butler方程相结合建立了预测多元电解质溶液表面张力的新型线性预测方程.新方程可由二元系数据预测多元系的表面张力数据,而不涉及任何多元交互作用参数.利用不同温度下24个混合电解质溶液的表面张力数据对新方程进行了系统检验.结果表明新方程可利用298.15K时二元系的渗透压系数和不同温度下二元系的表面张力数据预测不同温度下高浓度的多元系的表面张力数据,且预测结果与实验数据符合得很好,并且预测结果普遍优于基于Pitzer方程的表面张力模型.