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101.
Catalysis and deactivation of SO42−/ZrO2 solid acid on the alkylation of benzene and 1-dodecene were studied by the characterization of XRD, BET, IR, TG/DTA, and
NH3-TPD techniques and the determination of the 1-dodecene conversion, the yield of dodecylbenzene and the selectivity of linear
alkylbenzene respectively. In addition, some treatment methods, such as the extraction with benzene or THF as solvent, and
the calcinations with or without the dipping of H2SO4 in air, were respectively used to recover the activity of deactivated catalyst. The results indicate that SO42−/ZrO2 solid acid shows higher catalytic activity for the alkylation of benzene and 1-dodecene with nearly 100% of 1-dodecene conversion
and more than 80% of dodecylbenzene yield, and higher selectivity of 2-LAB. The activity of catalyst for the alkylation of
benzene is in proportion to the content and the strength of medium acid site. However, the distinct deactivation of catalyst
was also obversed in the alkylation. According to the characterization of deactivated catalyst, the accumulation of hydrocarbon
fragment and the removal of are mainly reasons of SO42−/ZrO2 deactivation. The SO42−/ZrO2 calcinated at higher temperature is apt to deactivate. The treatment by extraction with solvent or calcinations can recover
the catalytic activity of spent catalyst at a certain extent, especially calcination with the dipping of H2SO4.
Published in Russian in Kinetika i Kataliz, 2009, Vol. 50, No. 3, pp. 455–463.
The article is published in the original. 相似文献
102.
103.
重金属离子对猪胰α-淀粉酶活性影响的作用机理研究 总被引:17,自引:0,他引:17
通过在α-淀粉酶介质中加入Ce^3 ,Cd^2 和Pb^2 ,研究其对α-淀粉酶活性影响的作用机理。结果表明,低浓度重金属离子对酶活性有激活作用,高浓度则严重抑制酶活性。在高浓度下,Ce^3 ,Cd^2 和Pb^2 能完全竞争出α-淀粉酶中的Ca^2 。荧光滴定结果表明,Ce^3 ,Cd^2 和Pb^2 不仅可能完全占据Ca^2 的结合位点,而且还可能在Ca^2 的结合位点以外的氨基酸残基上结合,从而导致酶的构象改变。 相似文献
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107.
SUPG finite element method based on penalty function for lid-driven cavity flow up to $$Re = 27500$$
A streamline upwind/Petrov–Galerkin(SUPG)finite element method based on a penalty function is proposed for steady incompressible Navier–Stokes equations.The SUPG stabilization technique is employed for the formulation of momentum equations. Using the penalty function method, the continuity equation is simplified and the pressure of the momentum equations is eliminated. The lid-driven cavity flow problem is solved using the present model. It is shown that steady flow simulations are computable up to Re = 27500, and the present results agree well with previous solutions. Tabulated results for the properties of the primary vortex are also provided for benchmarking purposes. 相似文献
108.
Multi-walled carbon nanotube multilayers were modified onto a newly proposed gold hair microelectrode via a simple layer-by-layer assembling method.The resulting electrode showed a sensitive oxidation response to estradiol with detection limit as low as 1.0×10~(-8) mol/L,foreseeing a promising approach to the fabrication of high-sensitive microsensors. 相似文献
109.
Lin HE Xian Fu LIN* De Shui LV Zhi Chun CHEN Institute of Applied Chemistry of Zhejiang University Hangzhou 《中国化学快报》2001,(1)
Preparing the organized ultrathin film of proteins is the key to developing of protein-based molecular devices such as biosensors. In the past, the organized molecular layers were fabricated by the means of Langmuir-Blodgett (LB), which utilized the amphipathy of molecules. Molecular deposition (MD) which is based on the electrostatic interaction between the charged substrates and oppositely charged absorbate is a new and versatile method for preparing organized self-assembled ultrathin film… 相似文献
110.
Lan TAO* Ling Li ZHANG Shui Jun SHEN Xiao Ping HAN Department of Chemistry Hangzhou Teachers College Hangzhou 《中国化学快报》2001,(9)
1, 2, 4- and 1, 2, 3-triazole derivatives have found wide applications as plant growth regulators1, bactericides and medical fungicides2, insecticides3 and in dyeing and color development4.One of the general routes of synthesis of 1-aryl-1, 2, 3-triazoles was to treat aryl azides with a-keto phosphorus ylides in dry refluxing benzene for 0.5 to 2 days5. Herein we report, for the first time, a very quick and simple, microwave-promoted synthesis of 1-aryl-1, 2, 3-triazoles 3 from aryl azides 1 an… 相似文献