Investigation of Catalysis of Y-Ba-Cu-O Mixed Oxides in Phenol Hydroxylation

Superconductor Y-Ba-Cu-O mixed oxides were synthesized and their catalysis in phenol hydroxylation was studied too. Results show that, Y2BaCuO5 has better activity than that of YBa2Cu3O7-x, With the catalysis study of another mixed oxide La2CuO4 a conclusion that AO structure unit is the key for mixed oxides to have high activity in phyenol hydroxylation was drawn. Meanwhile, the effects of reaction temperature, medium and medium (water) pH on phenol hydroxylation catalyzed by Y2BaCuO5 and the stability of the mixed oxides were also studied.

STUDIES ON PREPARATION OF IRON, COBALT AND COPPER PHTHALOCYANINES Y ZEOLITE - CHARACTERIZATION AND THEIR CATALYSIS FOR HYDROXYLATION OF PHENOL

Iron, cobalt and copper phthalocyanines/Y zeolite, denoted as FePcY, CoPcY and CuPcY respectively,were prepared. The formation of metal phthalocyanine compounds within the cages of Y zeolite and their crystal structures were determined by elementary analyses, IR, UV-Vis, TG, BET, and XRD methods; The influence of experimental parameters upon phenol conversion and product selectivities was investigated as well.

STUDY OF A 1/12 PHOSPHOMOLYBDIC ANION DOPED POLYPYRROLE FILM ELECTRODE AND ITS CATALYSIS

A phosphomolybdic anion doped polypyrrole (PMo12O403- + PPy) film electrode has been prepared by electrochemical polymerization of pyrrole in an aqueous solution of 0.5 mol l-1 H2SO4 or 0.5 mol l-1 KNO3 containing PMo12O403- anions, and characterized by scanning electron microscopy and in-situ UV-visible spectroelectrochemical methods. The film electrode obtained is very stable upon potential cycling in acidic solution, but not in neutral solution. The catalytic effect of the film electrode on the reduction of ClO3- and BrO3- was studied.

ELECTROCHEMICAL CATALYSIS AT AN ULTRAMICROELECTRODE MODIFIED WITH REDOX SPECIES

General equations of the electrocatalytic reaction at an ultramicroelectrode modified with redox species have been described according to the Andrieux Saveant model. The electrocatalytic kinetic process has been discussed for the whole set of cases, ie (R), (R + S), (SR) (SR + E), (E), (R + E), (ER), (S), (ER + S) and (S + E) limiting situations. The effect of gamma on the catalytic steady state current shows that the higher the value of gamma, the lower the catalytic current. The kinetic process shifts rapidly from R to E with increasing values of gamma. It is favorable for catalysis only when gamma is very low. Therefore, the redox species modified ultramicroelectrode with thin film is utilized for electrocatalysis, and the larger the radius of ultramicroelectrode, the higher the catalytic efficiency.

HELIX-INDUCED ASYMMETRIC POLYMERIZATION

Asymmetric polymerization could be induced by an already formed optically active living prepolymer with one-handed screw sense helix conformation. The usually formed anionic active centre on the prepolymer could be changed to cationic, radical and even of Ziegler-Natta type. These living prepolymers with various kinds of active centre were all effective to induce a consequent asymmetric polymerization of a monomer which may be other than that in the prepolymer, to afford an optically active helical chain with the same screw sense as that of the prepolymer. Eight monomers have been used in the work. Optical rotation, circular dichroism and gelpermeation chromatography have been taken to prove the helix-induced asymmetric polymerization.

A NOVEL METAL THIAMINE COMPLEX WITH A CYCLIC DIMER FORMED BY METAL-BRIDGED 2 THIAMINE LIGANDS - CRYSTAL-STRUCTURE OF [MN(THIAMINE)CL2(H2O)]2[THIAMINE]2CL4.2H2O

The crystal structure of [Mn(thiamine)Cl2(H2O)]2[thiamine]2Cl4.2H2O has been determined by X-ray diffraction methods. The compound contains a cyclic dimer of a complex cation with two thiamine ligands bridged by two Mn(II) ions across a crystallographic center of symmetry. Each Mn(II) is coordinated by two chloride atoms, a water molecule, a N(1') atom of the pyrimidine from a thiamine and an O(53) atom of the hydroxyethyl side chain from another thiamine. There are two free-base thiamine molecules related by a center of symmetry in the unit cell, which form a base-pair through the hydrogen bonds. Both the independent thiamine molecules in the asymmetric unit assume the common F conformation with phi-T = 10.0(9) and 3.6(10) and phi-P = 85.6(7) and 79.6(7), respectively. The compound provides a possible model for a metal-bridged enzyme-coenzyme complex in thiamine catalysis. Crystallographic data: triclinic, space group P1BAR, a = 12.441(4), b = 13.572(4), c = 11.267(3) angstrom, alpha = 103.15(2), beta 89.03(3), gamma = 115.64(2)-degrees, Z = 1, D(calc) = 1.524 g cm-3, and R = 0.050 for 3019 observed reflections with I > 3-sigma(I).

ASYMMETRIC ALKYLATION MEDIATED BY CHIRAL PHASE-TRANSFER CATALYSTS

Seven chiral phase-transfer catalysts, among which three have not been reported so far, have been prepared and applied to the asymmetric alkylation of alpha-isopropyl benzyl cyanide and alpha-isopropyl-p-chlorobenzyl cyanide. The result showed that short reaction time, low temperature, high catalyst concentration and non-polar solvent would improve the optical yield. The influence of structure of the catalyst on the asymmetric reaction was preliminarily studied. The optical purity of the products were evaluated by gas chromatography with a chiral column.

Genetic characterization of asymmetric reciprocal hybridization between the flatfishes Paralichthys olivaceus and Paralichthys dentatus

Interspecific reciprocal crosses between the two flatfishes Paralichthys olivaceus and P. dentatus yielded hybrids with different viabilities. Specifically, the hybrids of P. olivaceus female and P. dentatus male (HI) were found to be viable, while the reciprocal hybrids from P. dentatus female and P. olivaceus male (HII) were completely inviable. All the HII individuals showed morphological deformities and died before first feeding. The chromosome analysis showed that HI individuals had the same chromosome number as parents. However, two chromosomes were missing in HII offspring indicating that the latter were aneuploids. Genomic inheritance from the parents to F-1 progeny was also examined by amplified fragment length polymorphism (AFLP) analyses, and the results showed differences between reciprocal hybrids. Almost all AFLP bands (97.71%) observed in parents were passed on to HI individuals. In contrast, only 86.64% of the AFLP bands from parents were scored in HII individuals. Frequency of lost parental bands was thus significantly higher in HII than that in HI and intraspecific crosses, which was probably associated with chromosomal elimination. In addition, higher segregation distortions were found in hybrids than in controls, although these differences were not significant. The present study indicates that chromosomal elimination and loss of AFLP loci occurred in inviable HII individuals, while such genomic changes were not found in viable HI individuals. Possible implications of such difference on genomic changes for asymmetric viability in reciprocal hybrids are discussed.