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21.
A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous highsurface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of mass transfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performance for hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of the traditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersed Rh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation of higher olefins such as 1-dodecene. 相似文献
22.
混合高序铜法立体选择性合成(±)┐EpilitsenolideC2陈祖兴李焰*黄精美黄锦霞徐章煌(湖北大学化学系武汉430062)关键词烷叉基二氢羟基甲基(3H)呋喃酮,混合高序铜,立体选择性反应1996-08-28收稿,1997-05-06修回湖北... 相似文献
23.
New polymeric adsorbents (ZH-02, ZH-03) containing benzoyl group for adsorbing and removing 4-methylaniline from its aqueous solutions were prepared. Studies on the isotherms and the comparison of desorption conditions evidenced through the adsorption of 4-methylaniline in water onto ZH-02 and ZH-03, namely that there are chemisorption‘s transitions at a proper higher temperature. Mini-colunm adsorption studies of 4-methylaniline on XAD-4, ZH-02 and ZH-03 at 288 K show that the breakthrough capacities are 2.39, 2.99 and 3.19 mmol/g and the total capacities are 3.45, 3.92 and 4.35 mmol/g, respectively. 相似文献
24.
M. P. Carril M. Soledad Corbillón J. Manuel Madariaga 《Accreditation and quality assurance》1997,2(6):301-308
The development of an analytical method for the determination of some heavy metals (Fe, Cu, Co, Zn and Ni) in fluoride compounds
[Cu(BF4)2, Sn(BF4)2, Pb(BF4)2 and HBF4] by flame atomic absorption spectroscopy is described. This method is to be used as a routine analytical method in an industrial
quality control laboratory. To this end the "performance characteristics" of an instrumental analytical method such as matrix
effects, sensitivity, linearity, detection and quantitation limits, precision and accuracy were evaluated for every system
under study. The results of these investigations showed that non-spectral interferences (due to the presence of large concentrations
of major metals such as Cu, Sn and Pb) were observed. Nevertheless it was possible to define a matrix concentration interval
where matrix effects were not statistically significant, and therefore a direct calibration approach could be used as the
calibration tool whenever the major metal concentration was not higher than 40×10–3 kg l–1. A guide to the developement of an analytical method for trace metal determination is provided. General tools for quality
control have been used in order to show how an analytical method can be tested daily and evaluated in a convenient manner.
Received: 29 January 1997 Accepted: 11 March 1997 相似文献
25.
Xichen CaiMichihiro Hara Kiyohiko KawaiSachiko Tojo Mamoru FujitsukaTetsuro Majima 《Tetrahedron letters》2003,44(32):6117-6120
Some triplet energy-transfer reactions initiated by photoexcitation of the triplet excited state of dibenz[a,h]anthracene to higher triplet excited states (DBA(Tn)) were observed in the presence of the triplet energy quenchers (Q) such as naphthalene, biphenyl, p-dichlorobenzene, and o-dicyanobenzene. In the case of carbon tetrachloride (CCl4) as Q, DBA(Tn)-sensitized decomposition of CCl4 occurred. 相似文献
26.
A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous high-surface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of masstransfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performancefor hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of thetraditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersedRh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation ofhigher olefins such as 1-dodecene. 相似文献
27.
介绍了非均匀相催化剂的MOVS制备方法,以该法制得的MoO3催化剂在甲醇选择氧化制甲醛、CO加氢制高级和喹啉加氢脱氮中均显示出常规催化剂更为优异的催化性能,并探讨了MOVS催化剂的内在特性与催化性能的关系。 相似文献
28.
YAN Zi-Feng 《天然气化学杂志》1996,5(3):261-271
Introduction0ncofthcintriguingpr0blcmsinhctcrogcncouscatal}'sisisthcactit'ationanddircctconversionofmcthancintoliquidfucIanduscful.h..i..l,lllMcthancactivationisvcry'difficultbccauscn1cthancisathcrmod}'namicalI}'stablccompoundt`ithanoblcgas-likcconfigurati0nThcvcry'strongtctrahcdralC-Hbonds(435kJ/mol)offcrnofiJnctionalgroups,magncticm0mcnts'orpolardistortionstofacilitatcchcmicalattackThismakcsmcthanelcssrcactivcthanncarl}'allitsconvcrsionproducts.Rccentl}'oxidativccouplinghasbecnconsidcrcda… 相似文献
29.
A. I. Bostan Yu. I. Pyatnitskii L. N. Raevskaya V. G. Pryanikova S. A. Nedil’ko A. G. Dzyaz’ko E. G. Zen’kovich 《Theoretical and Experimental Chemistry》2005,41(1):32-36
The oxidative coupling of methane (OCM) in a periodic regime over the SrMnO3 and its derivatives has been investigated. It has been established that partial replacement of the strontium ion by alkali metal ions leads to an increase in both catalytic activity and in selectivity with respect to higher hydrocarbons. Comparison of the results obtained in the present work with those obtained earlier for catalysts based on SrCoO3 led to the conclusion that the Co-containing catalysts were preferable to the Mn-containing catalysts for carrying out oxidative coupling of methane in a periodic regime.__________Translated from Teoreticheskaya i Éksperimentalnaya Khimiya, Vol. 41, No. 1, pp. 30–34, January–February, 2005. 相似文献
30.
Stefan Müller-Stach 《K-Theory》1995,9(4):395-406
LetX be a smooth projective variety over an algebraically closed fieldk. We repeat Bloch's construction of aG
m
-biextension (torseur)E over CH
hom
p
(X)×CH
hom
q
(X) forp+q=dim(X)+1. First we show that in characteristic zeroE comes via pullback from the Poincaré biextension over the corresponding product of intermediate Jacobians which has been conjectured by Bloch and Murre. Then the relations betweenE and various equivalence relations for algebraic cycles are studied. In particular we reprove Murre's theorem stating that Griffiths' conjecture holds for codimension 2 cycles, i.e. every 2-codimensional cycle which is algebraically and incidence equivalent to zero has torsion Abel-Jacobi invariant. 相似文献