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971.
A. L. Vereshchagin N. N. Pogodaeva A. A. Semenov 《Chemistry of Heterocyclic Compounds》1987,23(12):1302-1304
A spectrophotometric study of the acid-base properties of 3-acylindoles showed that they were stronger acids than the alkylindoles. It was found that protonation of these compounds occurs at the carbonyl group. For indolylglyoxal, 3-acetylindole, and 1-methyl-3-acetylindole the pKb was determined; the pKafor indolylglyoxal and 3-acetylindole was measured in 50% aqueous methanol.Translated from Khimiya Geterotsiklicheskhikh Soedinenii, No. 12, pp. 1621–1624, December, 1987. 相似文献
972.
S. V. Ketchik L. M. Plyasova A. E. Seredkin V. V. Kostrov L. N. Morozov 《Reaction Kinetics and Catalysis Letters》1980,14(4):429-434
Structural peculiarities of the formation of copper-aluminium catalysts at copper concentrations <10 wt% and calcination temperatures of 573–1173 K have been studied.
<10% . 573–1173°K.相似文献
973.
The concentration dependence of the apparent molar volumes of lithium halides (and electrolytes in general) in alcohols (and
solvents permitting association in general) is, in the first instance, due to changes in the degree of association and to
the inherent difference between the apparent molar volumes of the ions and of the ion pairs. Previous publications on the
molar volumes of electrolytes in organic solvents, disregarding altogether ion pairing, appear to be incorrect. Data from
the literature for lithium chloride and lithium bromide in normal primary alcohols and several branched alcohols from C1 to C8 and data from our laboratory for lithium halides in 1-hexanol and 2-ethyl-1-hexanol served for the determination of φ
V
and φ
E
. Electrical and structural contributions to the values of these functions for the ions and for the ion pairs are discussed. 相似文献
974.
The free NH3 molecule and the [Zn(NH3)4]2+ ion were studied by the kinematic coupling approach. The pure effects of this coupling were found to be small, and some modifications had to be introduced in order to get a reasonable force field. The force constants deduced for the skeletal vibrations are comparable with those of a quasi-exact force field. Calculated frequencies for [68Zn(NH3)4]2+ and [64Zn(ND3)4]2+ are reported in addition to those of [64Zn(NH3)4]2+. Mean amplitudes of vibration for [64Zn(NH3)4]2+ are given. 相似文献
975.
Chloride1), borohydrides2) and hydrides3) of dicyclopentadienyl thallium (III) and diindenyl thallium (III) have already been reported. The present communication deals with a study on the preparation and characterization of difluorenyl thallium (III) chloride, -hydride and -borohydride. 相似文献
976.
Miss Itawati Pratanata L. R. Williams R. N. Williams 《Journal of mass spectrometry : JMS》1974,9(4):418-421
When subjected to electron-impact, chloromethyl aryl sulphones (II, X = Cl) fragment predominantly by the loss of CH2Cl from the molecular ion followed by the loss of SO2 and in most cases the appropriate metastable peaks are present to confirm the transitions. In addition, alkyl–oxygen bond formation in the molecular ion was revealed by the presence of prominent peaks corresponding to the [R? ?-SO]+ ions. In most spectra no evidence for aryl–oxygen bond formation could be found and thus the presence of the chlorine atom was able to effectively reverse the direction of skeletal rearrangement reported for aryl methyl sulphones. 相似文献
977.
978.
The condensation of -substituted acetophenones with benzylidenebisurea in an acid medium has given 5-R-2-oxo-4,6-diphenyl-1,2,3,4-tetrahydropyrimidones. The analogous condensation of propiophenone forms 5-methyl-2-hydroxy-4,6-diphenylpyrimidine. The tetrahydro derivatives obtained are readily dehydrogenated to 5-R-2-hydroxy-4,6-diphenylpyrimidines.For part XX, see [1]. 相似文献
979.
M. F. Shostakovskii A. S. Atavin E. P. Vyalykh B. A. Trofimov N. A. Vodhol'skaya V. V. Keiko 《Russian Chemical Bulletin》1966,15(7):1239-1240
Conclusions Cyclic alkoxysilanes — 1,3-dioxa-2-silacyclanes — and their oligomers are decomposed by organomagnesium compounds with the formation of the corresponding silanols (disiloxanes) and tetraalkylsilanols.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1283–1285, July, 1966. 相似文献
980.
A. A. Pud G. S. Shapoval V. K. Skubin N. V. Kondrashova Yu. V. Kontsur G. M. Tel'biz 《Theoretical and Experimental Chemistry》1989,25(6):653-658
A study has been made of the electrochemical reductive breakdown (ECRB) of solid-phase chlorinated butyl rubber (CBR). It has been established that CBR does not accept electrons under conditions of fast sweep of electrode potential; however, with prolonged cathodic polarization of the substrate at the polymer/cathode/solution three-phase boundary, it undergoes reduction and subsequent chemical conversion, including intermolecular cross-linking and breakdown of the macromolecules. The rate of ECRB of the CBR depends on the potential and materials of the cathode, and also on the nature of the solvent. In a aprotic medium, the process of CBR breakdown leads to the formation of long polyconjugated structures that color its surface black in the vicinity of the three-phase boundary. In an aqueous medium, no such color is observed, but the products of ECRB are found to contain conjugated double bonds with a shorter conjugation chain than in the case of the aprotic medium. It has been established that he starting reaction in ECRB of CBR is reduction of the C-Cl bond and subsequent elimination of Cl–.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 6, pp. 710–715, November–December, 1989. 相似文献