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991.
F. Ritschl U. Rodemerck B. Kubias M. Meisel 《Reaction Kinetics and Catalysis Letters》1999,66(2):211-216
It is shown that the selectivity of furan formation from butadiene is not limited by the C−H bond strengths of the molecules
involved and that ring fission energies are not suitable data for the criterion applied. 相似文献
992.
993.
A simple wet chemical method is used to prepare zinc oxide nanoflowers (ZnO NFs) which were subjected to various characterization techniques such as XRD, FTIR, UV–Vis, FE-SEM, and XPS. XRD pattern indicates pure, crystalline, and monodispersed form with hexagonal wurtzite phase. The 3-D flower shape morphology with hexagonal ZnO nanorods was confirmed in FE-SEM. The synthesized ZnO NFs was used to study catalytic behavior in Kabachnik–Fields reaction under controlled ultrasound cavitation technique. High surface-to-volume ratio of ZnO NFs and the effect of ultrasonication enhances the yield of α-aminophosphonate. The catalyst was recycled and reused four times without any significant loss of its catalytic activity. Moreover, existing method becomes attractive and practical due to its easy, clean, fast, cost-effective, and eco-friendly procedure. 相似文献
994.
Bing Han Run-Feng HanYu-Wei Ren Xiao-Yong DuanYi-Chuan Xu Wei Zhang 《Tetrahedron》2011,67(31):5615-5620
4-Substituted dihydropyrimidinones and dihydropyrimidines were first efficient aerobic oxidized to the corresponding pyrimidinones and pyrimidines, respectively, in high yields by molecular oxygen in the presence of catalytic amount of N-hydroxyphthalimide (NHPI) and Co(OAc)2 in a mild and environmental benign condition. 相似文献
995.
996.
The kinetics of the oxidation of nickel (II) hexaaza and nickel (II) pentaaza macrocycles by the peroxydisulphate anion, S2O8
2−, were studied in aqueous media. Effect of pH on reaction rate was also studied. The rate increases with increase of S2O8
2− concentration. Rates are almost independent of acid betweenpH 4 and 2, giving overall a relatively simple second-order rate law followed by oxidation within the ion pair solvent shell.
Using rate =+1/2 d[Ni(L)3+]/dt =k[Ni(L)2+][S2O8
2−], oxidation rate constants were determined. 相似文献
997.
998.
Kiyotomi Kaneda Kazuya Yamaguchi Kohsuke Mori Tomoo Mizugaki Kohki Ebitani 《Catalysis Surveys from Japan》2000,4(1):31-38
Various Mg-Al type hydrotalcites were examined as catalysts for the epoxidation of olefins and N-oxidation of pyridines using hydrogen peroxide. The catalytic activity of hydrotalcites increased with increasing the basicity of their surface. Adding cationic surfactants, e.g., n-dodecyltrimethylammonium bromide, to the above system remarkably accelerated the reaction rate. The hydrotalcites, into which were introduced both Ru and Co cations in the Brucite layers, were found to be good catalysts for the oxidation of various alcohols in the presence of molecular oxygen. Moreover, these hydrotalcites could smoothly catalyze also the oxygenation of diphenylmethane, fluorene, and xanthene at benzylic position with excellent yields. The hydrotalcite catalysts could be easily separated from the reaction mixture and reused with retention of their high catalytic performance for the above oxidations. 相似文献
999.
1000.
高碘酸钾法测钢铁及合金中锰的改进建议 总被引:1,自引:0,他引:1
张萍 《理化检验(化学分册)》1999,(11)
试样经酸溶解后,以磷酸-高氯酸混合酸(4 1)或(9 1)氧化至冒烟.在硫酸、磷酸介质中,用高碘酸钾将锰氧化到七价,测其吸光度. 相似文献