共查询到20条相似文献,搜索用时 0 毫秒
1.
Reaction of methanol, carbon monoxide and hydrogen in the presence of a rhodium catalyst gives the homologization product, ethanol, with a selectivity of up to 50%, for a H2/CO ratio equal to 40. A mechanism for the reaction is suggested. 相似文献
2.
3.
Perfluoroalkyl iodides (RFI) react with organic halide in dissociants solvents (DMF,DMSO) in the presence of zinc-copper couple through an organometallic route; in this way C6F13Cl, C6F13CH2CH2I, (C6F13)2Zn have been prepared. 相似文献
4.
5.
We describe the direct homologation of a zinc-porphyrin into homoporphyrins on reaction with disubstituted diazoalcanes. The reaction may involve a zinc-carbenoid. At lower temperature competition with N-substitution was observed. We also describe a new series of homoporphyrins in which the supplementary carbon is inserted into a pyrrolic αβ bond. 相似文献
6.
Cr. Simionescu Sv. Dumitrescu S. Vasiliu V. Percec 《Journal of Thermal Analysis and Calorimetry》1974,6(3):389-399
The thermal stabilities of certain unsaturated polymers of the polyacetylene group, such as polyphenylacetylene, poly-p-chlorphenylacetylene and poly-p-methyl-phenylacetylene were investigated by the methods of thermal analysis. The kinetic parameters of the thermal decomposition reactions, e.g. the activation energy and order of reaction, were determined by the method of Freeman and Carroll. The polymers were synthesized by the photochemical polymerisation procedure, by ion coordination and polycondensation. Both the soluble and the insoluble fractions were studied. 相似文献
7.
The thermal analysis of sodium hexachloroiridate(III) obtained by the method indicated by us showed that the complex crystallizes with 10 water molecules which are lost in two steps: 8 and 2 water molecules, respectively. The final product of the thermal decomposition of the complex in an oxygen atmosphere is iridium(IV) oxide, while under inert gases metallic iridium is formed. Na3(IrCl6) · 10H2O crystallises in the rhombohedral system witha=16.677 Å andα=100°01′, space group R 3 m, d=2.29 and Z=9. A monoclinic pseudolattice was observed witha=8.338 Å,b=10.15 Å,c=12.52 Å andβ=107°06′ andZ=2. 相似文献
8.
9.
New chiral halotin derivatives with a diastereotopic anisochronous group bonded to the tin atom have been prepared. The rate of halogenhalogen intermolecular exchange is very low compared to the values found uptill now. 相似文献
10.
The effect of substitution on the aromatic ring in arenetricarbonylchromium complexes was studied by ESCA. The chemical shifts of the core ionisation energies (C 1s, O 1s, Cr 3s) of these derivatives have been measured and information on the bonding in these complexes have been obtained. 相似文献
11.
The thermal behaviour a series of polyphosphonates was studied by thermogravimetry (TG) and differential thermal analysis (DTA). The obtained data permitted the calculation of activation energies and reaction orders on decomposition zones by the Coats — Redfern method. 相似文献
12.
J. Barrau H. Lavayssiere G. Dousse C. Couret J. Satgé 《Journal of organometallic chemistry》1981,221(3):271-277
Desulfuration reactions of germadithiolanes by trialkylphosphines lead to germathiones via intermediate germathietanes. The formation of germylenes finally observed arises from reduction of germathiones by trialkylphosphines. Analogous reduction reactions of germanones by three coordinated linear and cyclic phosphorus compounds are also described. 相似文献
13.
《Materials Chemistry》1976,1(1):25-44
Pitting corrosion of titanium, studied under potentiostatic conditions, is only occurring at high potentials in halide aqueous solutions; valence of dissolution of titanium in pits is about 4. Pits growth kinetic can be described by i = ktn laws (n = 1,5 for the main stage of growth). Metallographic examination of pits associated with these results leads to propose a geometrical model of pits growth. Pits with hemispherical cap shape are growing under a passive film the nature of which, probably saline, should ascertain the polygonal edges of some pits by anisotropic dissolution of the film. On non anodically passivated titanium, interstitial or crevice type pitting corrosion observed on passivated surfaces, is occurring with increased sharpness. 相似文献
14.
Nabil El Murr 《Journal of organometallic chemistry》1976,112(2):177-187
Unlike ferrocene, cobalticinium cation is chemically inactive towards electrophilic substitutions and for this reason the number of derivatives in this series is limited. Substituted cobalticinium salts are usually prepared indirectly from substituted cyclopentadienyl derivatives. These intermediates can be obtained by treating substituted cyclopentadienes with strong bases or by reducing fulvenes. Various homo- and hereto-substituted cobalticinium salts have been prepared using this type of reaction. Due to the remarkable stability of the metallocenic skeleton of cobalticinium ion, we have succeeded in obtaining new derivatives transforming ring-substituted cobalticinium salts by known reactions. 相似文献
15.
Cycoladducts of furfurylakyl and arylketones with methyl acetylendicarboxylate undergo acid-catalysed rearrangement in high yield to 6-hydroxyphthalates bearing an acetonly or a phenacyl group in the 3-positionl. These phthalic compounds are useful intermediates for the synthesis of polyfunctional derivatives in the isocoumarin and the isoquinoline series. 相似文献
16.
The stereochemistry of the addition of the zinc derivative of ether PhCCCH2OMe, to aldehydes and ketones has been studied. In the case of saturated carbonyl compounds, the results can be explained by a mechanism which takes into account the steric effects of the substituents. However, with those which contain phenyl, vinyl or alkynyl groups in the α position, conformational and electronic factors must be considered. 相似文献
17.
Alain Deffieux Maurice Sepulchre Nicolas Spassky 《Journal of organometallic chemistry》1974,80(3):311-327
The reaction between organozinc or organocadmium derivatives and different chiral hydroxy compounds leads to the corresponding alcoholates and glycolates which can be used as initiators in polymerizations.The composition of such initiators is defined by the ratio iS = R-M-O/O-M-O of the number of alkylalkoxy groups to the number of dialkoxy groups. This ratio depends on the nature of the organometallic and hydroxy compound and on the conditions of reaction used to prepare them.Toward a given hydroxy compound, the reactivity of the organometallic derivatives follows the order: ZnEt2 > CdEt2 > CdMe2.Primary alcohols and 1,2-diols are more reactive than secondary alcohols in the case of organozinc compounds, while in the case of organocadmium compounds the secondary alcohols are more reactive than primary alcohols, but less reactive than 1,2-diols. The kinetics of the reaction can be followed by monitoring the variation of optical activity of the solution.Several compounds having definite stoichiometry have been isolated and identified by their NMR spectra. 相似文献
18.
en]Organotin amines react with α-enones to give various products depending on the nature of the initial carbonyl derivatives. 1,2 or 1,4-addition or, abstraction of an hydrogen from the α position were observed; each kinetic product being able to form a more stable species. 相似文献
19.
The conformations of biotin 1, cis 3,4-isopropylidenedioxythiophane 2, its 2,5-methylated homologs, 3, 4 and 5 and those of the corresponding sulfoxides and sulfones have been studied by NMR. Coupling constants, temperature and solvent effects show that all these compounds exist in a highly preferred conformation, the thiophane being in the envelope form with the sulphur atom out of the plane. In series 1, 2, 3 and 5 the arrangement is of the “boat-chair” type, in series 4 of the “crown” type, the sulphur being respectively cis and trans with respect to the other ring. 相似文献
20.
The reaction of substituted benzylidene anilines with 1,1-dicyano or 1-cyano 1-ethoxycarbonyl epoxides gives oxazolidines, the structures of which is established by NMR spectroscopy. The formation of oxazolidines proceeds via regiospecific addition of epoxide derived ylid to imine. The influence of ylid substituants and imine substituants on the reaction may be interpreted by interactions of the frontier orbitals. 相似文献