氢气存在下一氧化碳偶联反应的化学和性能

实验研究了在氢气存在下，一氧化碳与亚硝酸乙酯偶联合成草酸二乙酸反应体系在典型操作条件下的化学反应和反应性能，结果表明氢气只与反应体系中的亚硝酸乙酯反应生成乙醇。由于氢气与一氧化碳在催化剂表面竞争吸附，并且氢的存在打破了生成草酸二乙酯所必需的正常的氧化还原过程：Pd^0→Pd^2 →Pd^0，因此氢的引入使一氧化碳转化率及草酸二乙酯选择性下降。此外，化学吸附测试结果表明氢气和一氧化碳是在催化剂表面同一活性中心上吸附。     

Low potential electrosyntheses of free-standing polyfluorene films in boron trifluoride diethyl etherate

High quality free-standing polyfluorene (PFe) films were synthesized electrochemically by direct anodic oxidation of fluorene in pure boron trifluoride diethyl etherate (BFEE) on stainless steel sheet. The oxidation potential of fluorene in this medium was measured to be only 1.1 V versus SCE, which was much lower than that determined in acetonitrile + 0.1 mol L⁻¹ TBATFB. PFe films obtained from this medium showed good electrochemical behavior, good thermal stability with conductivity of 0.25 S cm⁻¹, indicating that BFEE is a better medium than acetonitrile for the electrosyntheses of PFe films. FTIR and ¹H NMR spectral investigations indicated that the polymerization of fluorene occurred mainly at 2, 7 position. As-formed PFe films can be partly dissolved in acetone, acetonitrile, tetrahydrofuran, etc.     

CO偶联反应中氧对Pd－Fe／α－Al2O3催化剂活性的影响

 在CO常压气相催化偶联合成草酸酯反应体系中，考察了原料气CO中不同氧杂质含量和不同反应温度对钯系催化剂活性的影响．结果表明，随着氧含量的增加和反应温度的升高，CO的转化率和草酸二乙酯（DEO）的空时收率升高，但DEO的选择性下降，且有副产物乙酸乙酯生成 ；氧杂质的存在同时加快了CO偶联主副反应速率．根据实验现象及XPS表征结果探讨了催化剂活性变化规律的机理，并考察了在反应温度下无CO偶联反应时氧对钯系催化剂中活性组分钯及助剂铁的氧化作用．实验结果表明，氧引起的钯系催化剂活性的改变具有可逆性．     

New poly(amide-imide) syntheses. V. Preparation and properties of poly(amide-imide)s based on the diimide—diacid condensed from 2,2-bis[4-(4-aminophenoxy)phenyl]propane and trimellitic anhydride

A dicarboxylic acid ( 1 ) bearing two pre-formed imide rings, was prepared from the condensation of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and trimellitic anhydride. A new family of poly(amide-imide)s having inherent viscosities of 0.53–1.68 dL/g was prepared by the triphenyl phosphite activated polycondensation from the diimide—diacid I with various aromatic diamines in a medium consisting of N-methyl-2-pyrolidone (NMP), pyridine, and calcium chloride. Most of the resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N-dimethylacetamide. All the soluble poly(amide-imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these poly(amide-imide)s were in the range of 237–293°C and the 10% weight loss temperatures were above 508°C in nitrogen. © 1993 John Wiley & Sons, Inc.     

三类引发剂引发苯乙烯聚合特性的比较研究和理论分析

用膨胀计法分别测定了氮 氮键引发剂偶氮二异丁腈 (AIBN)、氧 氧键引发剂过氧化二苯甲酰 (BPO)、碳 碳键引发剂 2 ,3 二氰基 2 ,3 二苯基丁二酸二乙酯的内消旋体 (I)和外消旋体 (II)在苯乙烯中的分解动力学参数 ,分解活化能分别为 :Ed(AIBN) =1 40 0 6kJ·mol-1,Ed(BPO) =1 2 0 3 3kJ·mol-1,Ed(I) =1 0 4 5 2kJ·mol-1,Ed(II) =89 5 6kJ·mol-1;分解活化熵分别为 :ΔS≠(AIBN) =76 3 2J·mol-1·K-1,ΔS≠(BPO) =1 2 76J·mol-1·K-1,ΔS≠(I) =-3 5 2 3J·mol-1·K-1,ΔS≠(II) =-80 84J·mol-1·K-1,并且II的极限转化率α∞ 表现出随温度升高而升高 ,I的α∞ 随温度升高先减小而后趋于平稳的趋势 ,这与AIBN和BPO引发苯乙烯聚合的极限转化率α∞ 随温度的升高而降低的规律有明显不同。对此用动力学链长综合常数k对T的微分结果并结合过渡态理论进行了分析。     

Polymerization of methyl methacrylate with cobalt acetylacetonate-diethyl zinc catalyst system

Polymerization of methyl methacrylate was studied with a cobalt acetylacetonate-diethyl zinc catalyst initiator system in benzene medium at 40°C. When the stoichiometric ratio of Zn/Co is 2, the activity for polymerization is found to be maximum. The structure of the obtained polymethyl methacrylate is compared with that obtained using a free-radical initiator such as benzoyl peroxide. The structure of polymer and the M?_w/M?_n values indicate that cobalt acetylacetonate-zinc diethyl system has pronounced free-radical characteristics. A suitable mechanism is proposed from the kinetic studies. © 1995 John Wiley & Sons, Inc.     

1,3-Dipolar addition of diethyl diazomethylphosphonate onto a CN double bond. Synthesis of triazolinyl and aziridinyl phosphonates

Cycloaddition of diethyl 1-diazomethylphosphonate onto a CN double bond is described. It was found that the reaction of this phosphorus diazomethane with benzylidene-alkyl-amines resulted in the formation of (1-alkyl-5-phenyl-4,5-dihydro-1H-[1,2,3]triazol-4-yl)-phosphonic acid diethyl esters, whereas its reaction with methylene-aryl-amines, generated from the corresponding hexahydro-1,3,5-triazines, led to diethyl esters of (aziridin-2-yl)-phosphonic acid.     

Reaction of glycidyl phenyl ether with imines: A model study of latent hardeners of epoxy resins in the presence of water

The hydrolyses of several imines and their reactions with glycidyl phenyl ether were examined under highly humid conditions as a model study for the development of water‐initiated hardeners for epoxy resins. Diethyl ketone‐based imines were hydrolyzed more efficiently than methyl isobutyl ketone‐based imines. The reactions of glycidyl phenyl ether with the imines depended on their hydrolysis rates and the basicity of the amines generated from them. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 971–975, 2002     

Neryl- and geranyltriethylammonium halides in the allylation of sodium diethyl malonate. The effect of the leaving group of the allylating reagent on the selectivity of the reaction

In the absence of catalysts,N-neryl-andN-geranyltriethylammonium halides can allylate sodium diethyl malonate to give terpene malonate derivatives. Using the above-mentioned ammonium salts, geranyl and neryl acetates, geranyl ethyl carbonate, and geranyl diethyl phosphate as examples, it has been shown that with Pd⁰ and Pd^II catalysts, the selectivity of the formation of neryl-, geranyl-, and linalylmalonates can be governed by varying the leaving group of the allylating agent.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 270–272, February, 1994.     

Reaction of α-ethoxyarolein with diethyl malonate

The reaction of α-ethoxyacrolein with diethyl malonate in the presence of EtONa, lithium diisopropylamide, or the Na₂CO₃−benzene−Et₃(PhCH₂)NCl catalytic system proceeds as the Michael addition. In the presence of an equimolar amount of triethylamine, selective 1,2-addition followed by dehydration of the 1,2-adduct occurs. Owing to the strong +M effect of the EtO group, α-ethoxyacrolein is a substantially less active Michael acceptor than acrolein. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2508–2510, December, 1998.