ELECTROCARBOXYLATION OF ORGANIC COMPOUNDS WITH CARBON DIOXIDE CATALYZED BY METALLOPORPHYRINS(Ⅰ)——CATALYTIC ACTIVITIES OF METALLOPORPHYRINS FOR ELECTROCARBOXYLATION OF BENZYL CHLORIDE

The electrocarboxylation of benzyl chloride with CO_2 catalyzed by metalloporphyrins and the effects of different kinds of central metals and ligands on catalytic activities are reported. These metalloporphyrins whose central metals can form corresponding M (Ⅰ) complexes such as CoTPP, FeTPP have high activities. With water-soluble porphyrin ligands such as TPPS, TTMAPI, the corresponding metalloporphyrins have high catalytic activity. Electron-with-drawing groups on the porphyrin ring cause the lowering of activity.     

INVESTIGATION OF THE SURFACE CHARACTERISTICS AND CATALYTIC ACTIVITY OF Sb_xO_y/SiO_2CATALYSTS FOR VAPOR-PHASE SYNTHESIS OF ISOPRENE FROM ISOBUTYLENE AND FORMALDEHYDE

The surface characteristics and catalytic activity of Sb_xO_Y/ SiO_2 catalysts forvapor-phasc synthesis of isoprene from isobutylene and formaldehyde have been investi-gated by TPR, XRD, XPS, IR and catalytic activity evaluation. The results show that whenthe Sb loadings are less than about 5 wt%,Sb_xO_Y is compIctely dispersed on the surface ofsilica to form a surface compound with Sb(V)=O group and the catalysts have relativelyhigh catalytic activity; when the Sb loadings are more than 5 wt%, in addition to this surfacccompound, the crystalline α-Sb_2O_4 is formed on the support surface and causes rapid de-crease of catalytic activity. It is suggcsted that the catalytic activity of Sb_xO_Y /siO_2 catalystsresults from synetgistic catalysis of the surface compound Sb(V)=O as the basic sites andthe surface silanol Si-OH as the acidie sites. The mechanism of this synergistic catalysis forisoprene production is discussed.     

Application of DEPBT on the Synthesis of the Protected Dipeptides Containing Histidine with Unprotected Imidazole Group by Solution Method

3- (Diethoxyphosphoryloxy)- 1,2,3-benzotriazln-4 (3H)-one (DE-PBT) was an organophosphorus coupling reagent developed by our group. It was an effective coupling reagent for the synthesis of protected peptides containing Tyr, Ser and Thr with unprotected hydroxy group on their side chain. The further study of the synthesis of a series of protected dipeptides containing hisfidine with unprotected imidazole group using DEPBT is reported. During the synthetic procedure, the imidazole group of histidine did not need to be protected. When the carboxyl components were N-protected aromatic amino acids or basic amino acids, the yields were relatively high (63%--81%). However,when the carboxyl components were N-protected acidic amino acids, the yields were relatively low (47%--48%). The results expanded the application of DEPBT on the synthesis of bioactive peptides containing histidine.     

ROLE OF MoO_3 AND La_2O_3 PROMOTERS IN Ni-CATALYZED METHANATION REACTIONS OF CO

A series of catalysts containing nickel were prepared by impregna-tion.The activity,heat resistance and sulfur resistance of catalysts were inves-tigated using catalytic microreactor.The experimental results show that the Ni/γ-Al_2O_3 catalysts containing molybdenum or lanthanum possess higher activity,better heat resistance and sulfur resistance than Ni/γ-Al_2O_3 catalyst.The sur-face behaviour of catalysts and the role of molybdenum or lanthanum in Ni-Mo-La/γ-Al_2O_3 system have been studied by XRD,TEM,XPS and TPY.It hasbeen shown that the addition of molybdenum or lanthanum can increase theconcentration of nickel atoms on the surface of catalysts,make the crystallinegranule of nickel smaller,increase the number of active centers of nickel andaffect the electronic structure of nickel.All these avtions will improve thecatalytic activity and surface behaviour of catalllysts.     

ELECTROCARBOXYLATION OF ORGANIC COMPOUNDS WITH CARBON DIOXIDE CATALYTZED BY METALLOPORPHYRINS(Ⅳ)——EFFECT OF VARIOUS FACTORS ON ELECTROCARBOXYLATION

The effects of various factors on the electrocarboxylation of organic compounds withcarbon dioxide catalyzed by metalloporphyrin are studied.The optimal potential of electrocar-boxylation is -1.6 V(vs.SCE).A weak protic solvent methanol can enhance catalytic activity.Tetrabutylammonium iodide is the best one of five electrolytes.The yields and current efficienciesof electrocarboxylation are increased slowly as the concentration of catalyst increases.     

THE PHOSPHORYLATION SITE OF SNAKE MUSCLE FRUCTOSE 1,6-BISPHOSPHATASE AND ITS PHOSPHORYLATION CONDITIONS

From the tryptic digests of phosphorylated snake muscle FruP_(2ase), a phosphoryl peptide has beenisolated, its amino acid sequence was Gly-Ala-Gly-Ser-Arg and the phosphorylation site was consideredto be on the serine residue. Effectors of the enzyme such as FruP_2, F6P and AMP did not affect thephosphorylation. The effect of pH on phosphorylation was consistent with that on the activity of theenzyme. The activity of phosphorylated enzyme was slightly lower than that of the native enzyme, thisdifference in activities between the two forms of the enzyme increased with decreasing the substrateconcentration. Results further support that a phosphorylated intermediate is involved in the catalytic reac-tion of FruP_(2ase).     

Artificial Esterase Based on Self-assembly Gel Microspheres Constructed from Chitosan and Amino Acids

A novel artificial esterase based on chitosan and amino acids was synthesized in the present study. The Fmoc-His and Glu were linked to chitosan by active ester method(AEM). The hydroxide radical in chitosan, imidazole group of Fmoc-His and carboxyl from Glu formed a catalytic center of natural esterase. Gel microspheres were coated with a protective layer and a supporting layer by seiassembly construction function in carboxymethylcellulose sodium(CMCS) solution. As for catalytic activity, chitosan-His-Glu was found to be more efficient than chitosan- His and chitosan-Glu in mimicking the core catalytic sites of natural esterase, and the best ratio(mass ratio) of chitosan-His-Glu:CMCS was 1:3. Furthermore, metal ions, such as Ca^2+, Mg^2+, Fe^2+, etc., were able to improve the catalytic efficiency of artificial esterase. And tlie Lineweaver-Burk plot indicated that the catalytic kinetics of artificial esterase conformed to Michaelis-Menten equation.     

过氧化氢溶液中单和双金属金-银纳米粒子氧化L-亮氨酸的动力学(英文)

The catalytic activity of surfactant stabilized mono-and bimetallic Au and Ag nanoparticles for the oxidation of an amino acid,L-leucine,was studied using hydrogen peroxide as the oxidant.The Au and Ag nanoparticle catalysts exhibited very good catalytic activity and the kinetics of the reaction were found to be pseudo-first order with respect to the amino acid.The effects of several factors,such as oxidant concentration,ionic strength,pH,and catalyst concentration on the reaction,were also investigated.In particular,optimal oxidant and catalyst concentrations were determined.Very high concentrations of the metal nano-catalysts or the oxidant led to a dramatic increase in reaction rate.Moreover,bimetallic Au-Ag catalysts provided higher selectivity than pure Au or Ag.     

SYNTHESIS OF DI（ETHYLMERCAPTOETHYL） AMINO GROUP—CONTAINING POLYSESQUISILOXANE PLATINUM COMPLEX AND ITS CATALYSIS IN HYDROSIL YLATION OF OLEFINS WITH TRIETHOXYSILANE

Three new polysesquisiloxane-bound platinum complexes were synthesized via hydrolysis of N,N-di(β-ethylmercaptoethyl)γ-(triethoxysilyl)propylamine or cohydrolysis of the monomer with dodecyltriethoxysilane or with phenylpropylthiethoxysilane and immobilixation on fumed silica,followed by reacting with potassium platinite in acetone under argon atmosphere.The platinum complexes exhibited high catalytic activity for the hydrosilylation of olefins by triethoxysilane. The effects of temperature and the amount of complex on the catalytic activity,as well as the recovery and reusability of the catalysts were investigated.     

CATALYTIC BEHAVIOR OF A SILICA-SUPPORTED POLYTITAZANE-PLATINUM COMPLEX FOR THE HYDROGENATION OF PHENOL

A new kind of inorganic polymer, viz. silica-supported polytitazane (Ti-N), and itsplatinum complex (Ti-N-Pt) were prepared. Cyclohexanone can be obtained in a maximumyield of about 62.2% in the hydrogenation of phenol over Ti-N-Pt at room temperatureunder atmospheric pressure. The effects of mole ratio of N/Pt in the complex, concentrationof the catalyst and reaction temperature on the catalytic activity and selectivity have beenstudied. The complex can be reused several times without loss in its catalytic activity.     

POLYMER-SUPPORTED LEWIS ACID CATALYSTS. Ⅵ. POLYSTYRENE-BONDED STANNIC CHLORIDE CATALYST

A polystyrene-bonded stannic chloride catalyst was synthesized by the method of lithium polystyryl combined with stannic chloride. This catalyst is a polymeric organometallic compound containing 0.25 mmol Sn (Ⅳ)/g catalyst. The catalyst showed sufficient stability and catalytic activity in organic reaction such as esterification, acetalation and ketal formation, and it could be reused many times without losing its catalytic activity.     

SYNTHESIS, CHARACTERIZATION OF IMIDAZOLATE-BRIDGED HETEROPOLY- NUCLEAR COMPLEXES AND THEIR ACTIVITY IN DISMUTATION OF O~(-)_(2)

A series of imidazolate-bridged heteropolynuclear complexes containing Cu2+ or Zn2+ were synthesized and characterized by reflectance spectroscopy, NMR and X-ray diffraction analysis. The bonding nature and the stability of imidazolate bridges in the complexes were studied by ESR spectroscopy, and the catalytic activity of the complexes in dismutation of O-2 was determined by NBT method. Results obtained indicate that the central Cu with N4 and N2O2 square planar or N4O square pyramidal coordination in which there is a weak bond H2O or ClO-4 on axial position, has a comparatively higher activity, but that with N5 square pyramidal having a strong bond axial ligand has almost no activity. Thus the results imply a possible formation of Cu-O-2 intermediate adduct in the catalytic process by Cu, Zn-SOD.     

A STUDY OF POLYBUTADIENE SYNTHESIS WITH MoCl_n(OR)_(4-n)-(i-Bu)_2AlOPh AS A CATALYST

The catalytic effect of Mo Cl_n (OR)_(4_n)-(i-Bu)_2AlOPh on the polymerization of butadiene inhydrogenated gasoline is studied (R is alkyl, cycloheptyl, phenyl of C_(4_16)). In this system, the solu-bility and the catalytic activity of the catalyst do not depend on whether the number of carbon atomsin R group is odd or even. The R group with the primary and secondary carbon atom has a fairlygreat influence on the catalytic activity. When R is an alkyl, the catalytic activity increases and therange of Al/Mo values that keeps higher conversion of butadiene is broadened as the size of the Rgroup increases. The content of 1,2-units in the polymer hardly varies with the size of the R group.     

CATALYTIC ACTIVITY OF Pd-Sn COMPLEX CARBONYLATION OF ACETYLENE

The influence of different concentration of HO, SnCl2, Cl- and n-BuOH on the carbonylation of acetylene has been studied. The results show that the yield of n- butyl propionate increases with the increase of HC1 concentration and the catalytic activity is depressed when Cl" concentration increases. However, the stability of catalytic complex is promoted by Cl-. The key to the carbonylation of acetylene lies in the addition of SnCl2, which promotes the formation of the complex of C2H2, CO with catalyst and plays an important role in the hydrogen removal from n-BuOH. The hydrogen removed from n BuOH is the hydrogen source of this reaction. Meanwhile, the principle of the effect of HCl, Cl- and SnCl2 on reaction has been discussed. The reaction model has also been proposed.     

Studies on Manganese Peroxidase Immobilized in Gelatin-containing Microemulsion-based Gels

The immobilized technique of manganese peroxidase (MnP) in gelatin-containing microemulsion-based gels and the effects of storage time and reuse times on its catalytic activity were studied. The results show that the MnP immobilized together with Mn^2 and H2O2 could effectively oxidize syringaldazine in n-heptane. The immobilized MnP still had a high catalytic activity after one-month storage under a freezing condition. The reuse times have a relation to the amount of the immobilized H2O2. When the amount of the immobilized H2O2 is sufficient, the microemulsion-based gels containing MnP could be used many times.     

CHARACTERIZATION OF IRON COMPLEXES SUPPORTED ON POLYMER AND THEIR CATALYTIC ACTIVITY IN BUTADIENE POLYMERIZATION

Styrene-acrylic acid copolymer (SAAC)-supported iron complex (SAAC·Fe)was characterized and the effect of the characteristic parameters on the catalytic activity of the complex was investigated. IR spectrum suggested that the complex SAAC·Fe possesses a structure of(C)and the Fe-O bond is higher in covalency.The complex SAAC·Fe with the structure of(C)shoved a higher catalytic activity in butadiene polymerization. When Fe/-COOH molar ratio in SAAC·Fe was about 0.2 the complex gave optimum catalytic activity. The catalytic activity of SAAC·Fe with the higher content of long sequence of acrylic acid units was low. When the content of the short sequence of acrylic acid units was predominant and at the same time the content of the short sequence was approximately equal to that of the long sequence for stryrene, the activity of the complex was high.     

Density Functional Theory Study on Organic Dye Sensitizers Containing Bis-dimethylfluorenyl Amino Benzofuran

The geometries, electronic structures, polarizabilities and hyperpolarizabilities, as well as the UV-Vis spectra of the two organic dye sensitizers containing bis-dimethylfluorenyl amino benzofuran were studied via density functional theory （DFT） and time-dependent DFT. The features of electronic absorption spectra were assigned on account of the agreement between the experiment and the calculations. The absorption bands in visible region are related to photoinduced electron transfer processes, and the dimethylfluorenyl amino benzo[b]furan groups are major chromophore that contributed to the sensitization of photo-to-current conversion. The role of vinylene group in geometry, electronic structure and spectra property is analyzed according to the comparative study of the dyes.     

ELECTROCARBOXYLATION OF ORGANIC COMPOUNDS WITH CARBON DIOXIDE CATALYZED BY METALLOPORPHYRINS(Ⅱ)——ELECTROSYNTHESIS OF SOME ORGANIC COMPOUNDS WITH CO_2 CATALYZED BY CoTPP

The catalyzation of CoTPP for electrocarboxylation of alkyl halides, alkenes and ketones with CO_2 are studied. The electrocarboxylation of these organic compounds with CO_2 in the presenec of catalyst can occur at more positive potential than that of no catalyst. The products of electrocarboxylation were identified by UV, IR and GC-MS. The electrocarboxylation mechanisms of different organic compounds are discussed.     

Kinetic studies of methanol synthesis from CO_2+H_2 over copper based catalysts

The catalytic activity for the synthesis of methanol from carbon dioxide and hydrogen wasmeasured on various binary and ternary catalysts containing copper oxide under a pressure of 10 atm.Among these samples the catalysts, CuO/ZnO/γ-Al_2O_3, demonstrated the highest activity andselectivity to methanol; MnO, as third component, had no promotional effect on the activity of meth-anol formation. Based on a simple power rate law the apparent activation energy estimation and par-tial pressure dependence measurement were accomplished over eight catalysts. The activation energiesvaried from 40 to 120 kJ / mol depending on the composition of catalysts. The rates of methanol for-mation to be 0.3 -- 0.9 order in H_2 and about 0.1 -- 0.2 order in CO_2 were reported.     

Synthesis and biological activities of dithiocarbamates containing1,2,3-triazoles group

Twelve novel dithiocarbamates containing 1,2,3-trizaoles group were prepared via one step starting from organic halides, dithiocarbamic acid prop-2-ynyl ester, and sodium azide, using a very simple catalytic system composed of copper（I） chloride and water at 70 8C. The structures of the new compounds were characterized and screened for their in vitro anti-tumor. Four of the compounds displayed varying levels of anti-tumor activity against the CDC25 B.