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821.
Carbon dioxide exerts a strong inhibitory effect on oxygen adsorption and complete oxidation of ethylene on silver but has little effect on the rate of ethylene oxidation to ethylene oxide.
.相似文献
822.
Summary 1. For a comparative study of the esterase activities of trypsin and thrombin on synthetic substrates we have obtained a number of N-arylsulfonyl derivatives ofl-arginine and their methyl esters containing substituents with different electronic natures and volumes in the benzene ring.2. The UV spectra and the ORD spectra of the compounds obtained have been studied.Sector of Molecular Biology and Genetics, Academy of Sciences of the Ukrainian SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 69–73, January–February, 1975. 相似文献
823.
Z. B. Rakhimkhanov A. S. Sadykov A. I. Ismailov A. K. Karimdzhanov 《Chemistry of Natural Compounds》1974,7(6):702-705
Conclusions Two anthocyanin glycosides have been isolated from the flowers ofHibiscus cannabinus var. simplex. One of them is a new glycoside, which has been called cannabinin, and the second is the known glycoside myrtillin, this being the first time that it has been isolated from the flowers of Kenaf hemp.Scientific-Research Institute for the Chemistry and Technology of Cotton Cellulose, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 723–727, November–December, 1971. 相似文献
824.
V. E. Tarabanko I. V. Kozhevnikov K. I. Matveev 《Reaction Kinetics and Catalysis Letters》1978,8(1):77-79
Oxidative coupling of thiophene and 2-methylfuran to the corresponding dihetaryls in DMFA medium occurs in the presence of the homogeneous catalytic system Pd(II)-molybdovanodophosphoric heteropolyacid (HPA). The data obtained show that HPA may act as a reversible oxidant in polar aprotic media.
, Pd(II)- 2- . , .相似文献
825.
The anomeric equilibrium of 2-methoxy-trans-5,6-dimethyltetrahydropyran was found to have an enhanced fraction of axial methoxyl compared to 2-methoxy-4- or 6-methyltetrahydropyran. The 2-methoxy-cis-5,6-dimethyltetrahydropyran did not. The enhanced anomeric effect is attributed to a steric repulsion between the trans vicinal Me groups. A similar effect is postulated for methyl glucoside and glucose pentaacetate. 相似文献
826.
A. G. Zyskin Yu. S. Snagovskii M. G. Slinko 《Reaction Kinetics and Catalysis Letters》1981,17(3-4):257-261
The dynamics of a closed isothermal system of constant volume consisting of an ideal gaseous mixture and particles adsorbed over the biographically inhomogeneous catalyst surface, has been studied. The existence, uniqueness and asymptotic stability of the point of detailed equilibrium in each positive reaction simplex has been proved.
, , . , , .相似文献
827.
Guoyi Bai Chenfang Zhang Yuecheng Zhang Haijun Yu Fei He Huisen Ning Ligong Chen 《Reaction Kinetics and Catalysis Letters》2007,90(2):373-380
The racemization of R-(-)-2-amino-1-butanol in a reaction using Co/γ-Al2O3 catalysts and catalysts modified by Mg or Ca was investigated in this paper. Complete racemization was achieved with a yield
of over 83% at using the Mg modified Co/γ-Al2O3 catalyst under optimized reaction conditions of 170°C and 2.5 MPa of H2. The catalysts were thoroughly characterized by XRD, XPS, TPR, SEM and TEM. The addition of Mg and Ca may be advantageous
for dispersing and stabilizing the active species of the Co/γ-Al2O3 catalyst, protecting from sintering, significantly improving its catalytic activity and stability. 相似文献
828.
The new nickel selenite chloride, Ni5(SeO3)4Cl2, was obtained by high-temperature solid state reaction of NiCl2, Ni2O3 and SeO2 in a 1:2:4 molar ratio at 700 °C in an evacuated quartz tube. Its structure was established by single-crystal X-ray diffraction. Ni5(SeO3)4Cl2 crystallizes in the triclinic system, space group P-1 (No. 2) with cell parameters of a=8.076(2), b=9.288(2), c=9.376(2) Å, α=101.97(3), β=105.60(3), γ=91.83(3)° and Z=2. All nickel(II) ions in Ni5(SeO3)4Cl2 are octahedrally coordinated by selenite oxygens or/and chloride anions (([Ni(1)O5Cl], [Ni(2)O4Cl2], [Ni(3)O5Cl], [Ni(4)O6] and [Ni(5)O4Cl]). The structure of the title compound features a condensed three-dimensional (3D) network built by Ni(II) ions interconnected by SeO32− anions as well as Cl− anions. Magnetic property measurements show strong antiferromagnetic interaction between nickel(II) ions. 相似文献
829.
O. S. Alekseev V. A. Poluboyarov Yu. A. Ryndin V. F. Anufrienko 《Reaction Kinetics and Catalysis Letters》1989,38(2):319-324
As shown by EPR, upon supporting Ni(-C3H5)2 on Ti/SiO2, the Ni complex is coordinated to Ti3+ ions. Deactivation of (Ni+Ti)/SiO2 catalysts so obtained during CO hydrogenation is due to the oxidation of Ti3+ ions and metallic nickel particles by reaction products.
, Ni(-C3H5)2 Ti/SiO2 Ni Ti3+. , (Ni+Ti)/SiO2 CO Ti3+ .相似文献
830.
M. A. Agzamova M. I. Isaev M. B. Gorovits N. K. Abubakirov 《Chemistry of Natural Compounds》1987,22(6):671-676
The quantitatively main glycoside — cycloorbicoside A — has been isolated from the epigeal parts of the plantAstragalus orbiculatus, and on the basis of chemical transformations and spectral characteristics its structure has been established as (23R,24S)-16,23:16,24-diepoxycycloartane-3,7,25-triol 3-0--D-xylopyranoside.Institute of the Chemistry of Plant Substances Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 719–726, November–December, 1986. 相似文献