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61.
Transformations of n-octane under hydrocracking conditions in a two-reactor flow-circulation system have been studied. It has been established that at high hydro-dehydrogenation activity of zeolite catalysts the reaction mechanism involves an initial step of paraffin dehydrogenation on a metal component and subsequent steps of cracking, isomerization and disproportionation of intermediate olefins on an acid component. Sodium content in zeolite determines the paraffin hydrocracking selectivity.
- - . , - , . .相似文献
62.
V. V. Kuznetsov Z. V. Bondarenko T. V. Pshenichkina N. V. Morozova V. N. Kudryavtsev 《Russian Journal of Electrochemistry》2007,43(3):349-354
Kinetics of processes of electrochemical production of a cobalt-molybdenum alloy out of an ammonia-citrate electrolyte is studied. The electrolyte’s composition is similar to that used for depositing a nickel-molybdenum alloy. It is established that the cobalt-molybdenum alloy undergoes deposition at smaller values of pH (5.0–6.0) than the nickel-molybdenum alloy (7.0–9.0). The current efficiency for the cobalt-molybdenum alloy is substantially dependent on the electrolyte pH, whereas the chemical composition of the obtained deposits is practically independent of the electrolyte pH in the pH interval 5.0–8.0 at current densities of 0.025 to 0.100 A cm?2. On the other hand, a change in the electrolyte pH produces a considerable effect on the morphology of the obtained deposits. At large values of pH (pH 8.0), one can obtain a powder-like deposit of the cobalt-molybdenum alloy with a small value of the current efficiency. The deposits that are obtained in the pH region 5.0–6.0 have some cracks, with the number of cracks increasing with the electrolyte pH. 相似文献
63.
V. E. Tarabanko N. A. Fomova B. N. Kuznetsov N. M. Ivanchenko A. V. Kudryashev 《Reaction Kinetics and Catalysis Letters》1995,55(1):161-170
The influence of catalyst (CuSO4 solution), pH and temperature on the vanillin formation and oxygen consumption in oxidation of lignin in alkaline media have been studied. It was shown that the main role of catalyst in the lignin oxidation is to change the selectivity of hydroperoxide fragmentation rather than to accelerate oxidation. 相似文献
64.
Kuznetsov R. M. Balueva A. S. Litvinov I. A. Gubaidullin A. T. Nikonov G. N. Karasik A. A. Sinyashin O. G. 《Russian Chemical Bulletin》2002,51(1):151-156
The reaction of bis(hydroxymethyl)phenylphosphine with 4,4"-diaminodiphenylmethane in DMF afforded 1,1",5,5"-bis[methylenedi(p-phenylene)]di(3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane) (1) whose structure was established by X-ray diffraction analysis. Sulfurization and oxidation of macrocyclic tetraphosphine 1 gave rise to products 2 and 3, respectively, compound 3 being obtained as a stable hexahydrate. The reaction of bis(hydroxymethyl)phenylphosphine with bis(4-N-methylaminophenyl)methane in DMF followed by sulfurization yielded monocyclic bis{methylenedi[p-phenylene(N-methyl)aminomethyl]}di(P-phenyl)phosphine sulfide (4). 相似文献
65.
L. A. Zemnukhova R. L. Davidovich V. N. Rykovanov S. I. Kuznetsov S. K. Shcherbakova G. K. Semin 《Russian Chemical Bulletin》1987,36(7):1385-1387
Conclusions We have studied the temperature dependence of the NQR parameters of123Sb and81Br in the range 77–360 K for the complexes of MSbBrF3 (M=Na, Cs, NH4) and Cs3Sb2Br9. We have established the temperature regions for which piezoelectric properties appear in the crystal hydrate NaSbBrF3.H2O, and in the compounds MSbBrF3 (M=Na, NH4) and Cs3Sb2Br9 anomalous changes appear in the dependences of the quadrupole coupling constant, the asymmetry parameter of the electric field gradient for the antimony atoms and the resonance frequency of the bromine atoms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1501–1504, July, 1987. 相似文献
66.
E. E. Stashenko P. I. Zakharov V. V. Kuznetsov I. V. Klyavina L. M. Kirilova A. V. Varlamov N. S. Prostakov 《Chemistry of Heterocyclic Compounds》1989,25(6):657-662
The fragmentation of different alkyl(aryl) substituted piperideines [tetrahydro-pyridines] was studied by analyzing high-resolution mass spectra and DADI [Direct Analysis of Daughter Ions] spectra. It was shown that the retrodiene decomposition of the ring is suppressed by competing processes of elimination of ring substitutents. The nature of the substituents and their mutual disposition on the ring have a substantial influence on the extent of their cleavage from the ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 795–800, June, 1988. 相似文献
67.
The possibility was studied of using bromine derivatives, analogous to those of chlorines, in the synthesis of 1,2-dialkyldiaziridines, and it was shown that NaOBr successfully replaces NaOCl, while RNHBr gives good results in water in the presence of an excess of amine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2090–2094, September, 1989. 相似文献
68.
Elli S Ganazzoli F Timoshenko EG Kuznetsov YA Connolly R 《The Journal of chemical physics》2004,120(13):6257-6267
Single-chain simulations of densely branched comb polymers, or "molecular bottle-brushes" with side-chains attached to every (or every second) backbone monomer, were carried out by off-lattice Monte Carlo technique. A coarse-grained model, described by hard spheres connected by harmonic springs, was employed. Backbone lengths of up to 100 units were considered, and compared with the corresponding linear chains. The backbone molecular size was investigated as a function of its length at fixed arm size, and as a function of the arm size at fixed backbone length. The apparent swelling exponents obtained by a power-law fit were found to be larger than those for the corresponding linear polymers, indicative of stiffening of the comb backbone. The probability distribution function for the backbone end-to-end distance was also investigated for different backbone lengths and arm sizes. Analysis of this function yielded the critical exponents, which revealed an increase in the swelling exponent consistent with values found from the molecular size. The apparent persistence length of the backbone was also determined, and was found to increase with increasing branching density. Finally, the static structure factors of the whole bottle-brushes and of their backbones are discussed, which provides another consistent estimate of the swelling exponents. 相似文献
69.
A method has been developed for the synthesis of 4-amino-substituted 7-benzyl-2-morpholin-4-yl-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidines
by condensation of ethyl 1-benzyl-3-oxopiperidine-4-carboxylate with morpholine-4-carboxamidine and subsequent reaction of
the 7-benzyl-2-morpholin-4-yl-5,6,7,8-tetrahydro-3H-pyrido[3,4-d]pyrimidin-4-one with trifluoromethanesulfonic anhydride and
secondary amines.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 762–768, May, 2007. 相似文献
70.
I. V. Shcherbakova V. G. Brovchenko E. V. Kuznetsov 《Chemistry of Natural Compounds》1985,21(6):774-777
The reaction of 6,7-dimethoxy-1-methyl-2-benzopyrylium salt with ammonia forms the corresponding isoquinoline, and its reaction with methylamine and benzylamine forms mixtures of the corresponding isoquinolinium salts and naphthylamines. The reduction of 2-benzyl-1-methyl-6,7-dimethoxyisoquinolinium perchlorate with sodium tetrahydroborate has given the corresponding tetrahydroisoquinoline, the hydrogenolysis of which has led to salsolidine. The products have been characterized by elementary analyses and IR and PMR spectroscopy. 相似文献