STUDY OF Cu-Mu CATALYST FOR THE SYNTHESIS OF METHYL FORMATE AND METHANOL FROM SYNTHESIS GAS

将一种新型的ＣｕＭｎ催化剂用于由合成气合成甲酸甲酯和甲醇，该催化剂表现出良好的反应活性和甲酸甲酯选择性。考察了反应温度、合成气压力及催化剂制备方法等对合成甲酸甲酯和甲醇的反应活性及选择性的影响。在反应条件下，产物收率最高达６０．１０ｇ／（Ｌ·ｈ），产物甲酸甲酯的选择性很高。用ＢＥＴ、ＸＲＤ及ＸＰＳＡｕｇｅｒ等测试方法对催化剂的比表面、晶相组成以及铜、锰在催化剂中的价态进行了表征，并探讨了催化剂失活的原因。     

Solvent effect on reaction rates: Reaction between sodium ethoxide and methyl iodide in ethanol + cyclohexane solvent systems

The kinetics of the reaction between sodium ethoxide and methyl iodide has been studied at 25°C in various cyclohexane-ethanol solvent mixtures with a cyclohexane content of 10 to 50% per volume. The determination of the rate constants att=0 were carried out by a new iterative method proposed in this investigation. The obtained results show that the reaction rate decreases with the increasing cyclohexane content. This behavior can be attributed to various solute-solvent interactions of electrostatic nature. On the other hand, the variation of ion and ion pairs rate constants with solvent composition permits the various solvation effects to be taken into account.     

α-羰基硫代甲酰胺与溴的反应研究

报道了α 羰基硫代甲酰胺与溴在三乙胺存在下的反应 ,合成了二 [( 1 芳基亚胺基 1 苯甲酰基 )甲基 ]二硫醚类化合物 ,产率为 60 %～ 65 %.它们的结构经元素分析、红外光谱、核磁共振光谱和质谱分析得到确证     

Heterocyclization of 1,1-dicyano-2-(trifluoromethyl)ethylenes with 1,3,3-trimethyl-3,4-dihydroisoquinoline and its derivatives

1,3,3-Trimethyl-3,4-dihydroisoquinolines react with 1,1-dicyano-2,2-bis(trifluoromethyl)ethylene to give 4-amino-6,6-dimethyl-2,2-bis(trifluoromethyl)-3-cyano-6,7-dihydro-2H-benzo[a]quinolizines. The reaction of 3,3-dimethyl-1-cyanomethylidene-1,2,3,4-tetrahydroisoquinoline and the methyl ester of 3,3-dicyano-2-(trifluoromethyl)acrylic acid leads to 5,5-dimethyl-3-oxo-2-(trifluoromethyl)-2-(dicyanomethyl)-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline.A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1888–1892, August, 1992.     

STRUCTURE AND PROPERTIES OF P(MMA-MAA)/PEO INTERMACROMOLECULAR COMPLEX FORMED THROUGH HYDROGEN BONDING

The superstructure and properties of polymers might be improved and enhanced througl intermolecular complexation. In this paper, the preparation, structure and properties of P(MMA-MAA)/PEO intermolecular complex through hydrogen bonding are studied. By acid hydrolysis of PMMA, a series of P(MMA-MAA) copolymers have been prepared, the MAA content of which depends on the temperature and time of hydrolyzation. In case the MAA content in P(MMA-MAA) is beyond 0.4 mole fraction, the hydrogen bonding between P(MMA-MAA) and PEO is strong enough to form intermolecular complex. The supermolecular structure of the complex is quite different from that of its constituent, which was observed by an X-ray diffraction and transmission electron microscope. The crystallization of PEO is confined owing to complexation. The complex exhibits quite a lot of good properties in thermal stability, gas permeability as well as mechanical strength, and could be used in many fields.     

Study of the influence of physical aging on macroradical decay in poly(methyl methacrylate)

The macroradical decay in poly(methyl methacrylate) samples with different thermal histories was investigated in the temperature interval 20–100 °C using ESR spectroscopy and the second order kinetic model. The rate constants exhibit two different regimes with the transitions atT _tr=68±1°C which are independent of thermal treatment. ForT<T _tr andT>T _tr the rate constants as well as the corresponding activation parameters are sensitive to history because of different physical microstructures. The compensation law, i.e., the linear relation between lnk _{o, eff} andE _eff, was analyzed in terms of the so-called compensation quantitiesk _c andT _c and a proximity betweenT _c=T _tr andT _o=53±3 °C — Vogel temperature for -segmental dynamics was found. A comparison of kinetic and dynamic data suggests that the decay of terminal macroradicals in the low-temperature region is controlled by secondary relaxations and that the -mobility contributes to a more rapid decay at higher temperatures belowT _g.     

Synthesis of esters ofpara-hydroxy substituted α-trifluoromethylmandelic acids

Methyl trifluoropiruvate in trifluoroacetic acid at 20 °C rapidly C-hydroxyalkylates various phenols at thepara-positions to afford the corresponding esters ofpara-hydroxy substituted -trifluoromethylmandelic acids.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 528–530, March, 1995.The present study was carried out with the financial support of the Russian Foundation for Basic Research (Project code 93-03-22696).     

Prediction of the retention indices of methyl pyridines and pyrazines in capillary gas chromatography based on the non-linear additivity of the sorption energy

Summary Methylbenzenes, pyridines and pyrazines were investigated on fused-silica and glass capillary columns coated with SE-30 and PEG-40M/KF liquid phases, at two temperatures, 80° and 110°C. The contribution of the methylene groups to the partial molar free sorption energy was determined for methylpyridines and pyrazines. Equations are proposed for the calculation of the retention indices of methyl pyridines and pyrazines. These equations are based on the ortho- and α-effects of the methyl groups. The predicted indices have been experimentally tested for six dimethyl- and trimethylpyridines, and four methylpyrazines. Good accuracy of the calculation permits to use this method for the identification of methylpyridines and pyrazines in complex mixtures. Enlarged text of the paper presented at the Eighth International Symposium on Capillary Chromatography, Riva del Garda, Italy, May 19–21, 1987.     

Thermogravimetric analysis of poly(alkyl methacrylates) and poly(methylmethacrylate-g-dimethyl siloxane) graft copolymers

The thermal stabilities of various poly(alkyl methacrylate) homopolymers and poly(methyl methacrylate-g-dimethyl siloxane) (PMMA-g-PSX) graft copolymers have been determined by thermogravimetric analysis (TGA). As expected, the thermal stabilities of poly(alkyl methacrylates) were a function of the ester alkyl group, and polymerization mechanism. In particular, thermally labile linkages, which result from termination during free radical or nonliving polymerization mechanisms, decrease the ultimate thermal stabilities of the polymers. However, graft copolymers, which were prepared by the macromonomer technique with free radical initiators, exhibited enhanced thermal stability compared to homopolymer controls. A more complex free radical polymerization mechanism for the macromonomer modified polymerization may account for this result. © 1994 John Wiley & Sons, Inc.