Study of Manganese Promoter on a Precipitated Iron-Based Catalyst for Fischer-Tropsch Synthesis

The effects of Manganese(Mn)incorporation on a precipitated iron-based Fischer-Tropsch synthesis(FTS)catalyst were investigated using N_2 physical adsorption,air differential thermal analysis (DTA),H_2 temperature-programmed reduction(TPR),and M(?)ssbauer spectroscopy.The FTS perfor- mances of the catalysts were tested in a slurry phase reactor.The characterization results indicated that Mn increased the surface area of the catalyst,and improved the dispersion ofα-Fe_2O_3 and reduced its crystallite size as a result of the high dispersion effect of Mn and the Fe-Mn interaction.The Fe-Mn inter- action also suppressed the reduction ofα-Fe_2O_3 to Fe_3O_4,stabilized the FeO phase,and(or)decreased the carburization degree of the catalysts in the H_2 and syngas reduction processes.In addition,incorporated Mn decreased the initial catalyst activity,but improved the catalyst stability because Mn restrained the reoxidation of iron carbides to Fe_3O_4,and improved further carburization of the catalysts.Manganese suppressed the formation of CH_4 and increased the selectivity to light olefins(C_(2-4)~=),but it had little effect on the selectivities to heavy(C_(5 )) hydrocarbons.All these results indicated that the strong Fe-Mn interaction suppressed the chemisorptive effect of the Mn as an electronic promoter,to some extent,in the precipitated iron-manganese catalyst system.     

A Study on bioactivity of Corn Peptides with Low Molecular Weight（Ⅰ）——Effect of an Intake of them on Alcohol Metabolism in Rats

IntroductionIn the past few years,some researchers foundthat small peptides derived from the hydrolysate offood protein play an important role in regulatingautonomic nervous system,activating the cellularimmunity function,ameliorating the cardiovascularfunction,antioxidizng and antaging,etc.[1— 8] .Par-tial proteolysis is effective for improving the func-tional properties of protein.Small peptides havesome advantages compared to protein,such as lowosmotic pressure,fast absorption,good taste a…     

Synthesis and Characterization of Poly(isoprene-b-butyl methacrylate) Block Copolymer in the Presence of Rare Earth Catalyst

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Effect of Glucose-lowering of Heteropolytungstogermanate β-K_6H[GeW_9V_3O_(40)]·9H_2O

IntroductionThe main abnormality in insulin- dependentdiabetes mellitus is heperglycemia due to thedeficiency of insulin. At present severe diabetescan be controlled only by dialy injections of insulin,so the development of some compounds that servethe function of insulin or as insulin mimetics onoral administration would be very helpful.The finding in 1 985 that vanadate ( + 5oxidation state of vanadium) shows an in vivoinsulin- like effect stimulated the research oninsulin- mimetic vanadium[…     

The Synthesis of Poly(ethylene oxide)-Block-Polybutylacrylate

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Synthesis and Crystal Structure of One-dimensional Chain Complexes [K(18-C-6)]2[M(mnt)2](M=Zn, Hg)

IntroductionThe 1 ,2 - dicyanoethene- 1 ,2 - dithiolato anion isa bidentate ligand.It can form square- coplanarcomplexes with many transition metal ions and hasfound a lot of application in analytical chemistry,catalyst and biochemistry.In recent years,metalcomplexes containing mnt and its dithiolate analogligands have been extensively studied and have re-ceived considerable attention due to their potentialapplication in charge transfer and storage,molecu-lar metals,magnetic materials,supercon…     

Fluorescence Microscopic Image Analysis of Nucleic Acids Based on The Capillary Flow Directed Assembly Ring of Neutral Red-nucleic Acid Supramolecular Complexes

IntroductionIt is well known thata ring- like deposit can beformed when a droplet of coffee is splashed onto atable. The reason for this has recently been investi-gated and determined to be the solvent transporta-tion from the interior of the droplet in order tocompensate for the solvent evaporative loss at theperiphery of the droplet spot[1] . The solventtrans-portation thus forms a capillary flow that carriesthe solute to the periphery of the spot,where thesolute accumulates to form a ring- …     

Preparation of Porous ZrO2 and Study on Its Properties

IntroductionSolid super- strong acid SO2 -4/ Zr O2 can be usedat a high temperature,dissociated from productand reactivated easily[1— 3 ] . Researchers have madeefforts to investigate into it[4— 7] . However,it hassome shortcomings of lower specific surface area,afewer number of surface acid centers,and easyinactivation. Generally,zirconia for catalyticapplication is prepared by the calcination ofhydrous zirconia above 70 0 K,or by the hydrolysisof zirconium tetrachloride at a high tempera…