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Formaldehyde can be synthesized (Turnover number=10) from sodium methoxide and carbon dioxide using the anionic tungsten carbonyl complex [(CO)₅WCl]⁻ as catalyst precursor and a molar ratio NaOMe/W lower than 8 at 125°C, 400 psi of CO₂ for a 24-h period. The most probable mechanism involves the generation of the [(CO)₅WOCH₃]⁻ species by the reaction of [(CO)₅WCl]⁻ with NaOMe. The methoxide complex can undergo β-hydrogen abstraction to yield formaldehyde and the terminal hydride [(CO)₅WH]⁻, which in turn, decomposes under reaction conditions to provide the bridging hydride [(μ-H)W₂(CO)₁₀]⁻. Carbon dioxide insertion into the complex [(CO)₅WH]⁻, followed by reaction of NaOMe regenerates the alkoxide compound [(CO)₅WOCH₃]⁻ and sodium formate. A kinetic study of the reaction of [(CO)₅WCl]⁻ with NaOMe suggests that the mechanism involves nucleophilic attack of the base on the metal center, and proceeds by two different pathways depending on the molar ratio base/metal. For a ratio NaOMe/W < 8 the β-hydrogen reaction takes place with the formation of [(μ-H)W₂(CO)₁₀]⁻ and formaldehyde. For higher base/metal ratio (>8) the formation of metal cluster is observed.

The intolerance of a large number of children and adults for the lactose containing products caused a wide spread of investigations of the decrease of this bisaccharide in meals carried out by the application of such enzymes as β-galactosidases. The properties of four different commercial preparations of β-galactosidase originating from bacteria and fungi are described. The native enzymes are compared with their immobilized forms. pH and temperature optimalization and stability curves are presented not only for the immobilized enzymes but also for those which were additionally cross-linked with glutaraldehyde or bis-oxirane. Lactozym 3000 in an immobilized form seems to be the most useful for the delactatic process of commercially available milk.

A series of TiO₂SiO₂ catalysts were prepared by coprecipitation from the mixed solution of titanium tetrachloride and sodium silicate. Some of the sample were modified with 0.5 M H₂SO₄ and used as modified catalysts. The addition of TiO₂ to SiO₂ caused the increase of acidity and acid strength, and the shifts of OH and SiO stretching bands of silanol group to lower frequencies in proportion to the TiO₂ content. Catalytic activities for 2-propanol dehydration and cumene dealkylation increased in relation to the increase of acidity and the band shifts to lower frequencies. The catalytic activities of modified catalysts were higher than those of unmodified catalysts, and the effect of modification on catalytic activity was higher for 2-propanol dehydration than for cumene dealkylation. The effect of modification on catalytic activity increased with increasing TiO₂ content of the catalysts. Actually, 92-TiO₂SiO₂/SO²⁻₄ had the highest increment in catalytic activity and 10-TiO₂SiO₂/SO²⁻₄ had the lowest increment for the 2-propanol dehydration.

The Cu^II—diamine complexes, (bipy)CuSO₄ and (tmen)CuSO₄, catalyze the hydrolysis of p-nitrophenyl diphenyl phosphate (PNDP) adsorbed on a strong-base ion exchange resin. Turnover is observed. The major hydrolysis products are diphenyl phosphate, p-nitrophenyl phenyl phosphate, and the ethanolysis product ethyl diphenyl phosphate (EDPP) which are observed in similar amounts in both the presence and absence of the Cu^II—diamine catalysts. The apparent bimolecular rate constants found for the (bipy) CuSO₄ and (tmen)CuSO₄ catalysts are 0.023 and 0.024 M⁻¹ s⁻¹, respectively. CuSO₄ is inactive as a catalyst. ³¹P MAS NMR relaxation measurements of the stable EDPP product reveal that the Cu^II—diamine complexes greatly enhance T₁ relaxation, whereas CuSO₄ has only minimal effect. These results are consistent with the complexation of neutral phosphorus esters by the Cu^II—diamine catalysts. ³¹P T₁ measurements of hydrolytically-stable dimethyl methylphosphonate (DMMP) in water solutions of Cu²⁺, (tmen)Cu²⁺, and Mn²⁺ suggest that DMMP exchanges rapidly between inner-sphere and outer-sphere complexes in a nearly identical manner with each of these paramagnetic species.

A tartaric acid—sodium bromide—modified Raney nickel (TANaBrMRNi) is a unique catalyst for the enantioface-differentiating hydrogenation of 2-alkanones and β-ketoesters. The addition of carboxylic acid to the reaction system results in improvement of the optical yield over this catalyst. In this study, the enantioface-differentiating hydrogenations of 2-octanone and methyl acetoacetate were carried out to clarify how the added carboxylic acids improve the efficiency of the enantio-differentiation of the substrates over TANaBrMRNi. The participation of the conjugate bases and protons generated from the added carboxylic acid during the hydrogenation of 2-alkanones and β-ketoesters is proposed.

Experiments were conducted aiming for the reduction of coordinated nitrogen in mononuclear end-on dinitrogen complex, [Ru (Hedta) N₂]⁻ and dinuclear bridged complex, [Ru (Hedta)]₂N²⁻₂ using the conduction band electrons of illuminated Pt/CdS (λ_ex= 505 nm). It has been found that the dinitrogen in mononuclear end-on complex is more easily reduced to ammonia.

The physicochemical properties of lipase from Candida rugosa in the hydrolysis of micellized p-nitrophenyl palmitate, such as thermal stability, enzyme concentration and the effect of ionic strength on the rate of catalysis, have been characterized. As regards the specificity for a series of p-nitrophenyl esters (p-NPCn), n = 2, 4, 8, 12 and 16 being the number of carbon atoms of the hydrophobic tail, the lipase from Candida rugosa proved to be non-specific, although it did hydrolyze them at different rates, depending on n and the physicochemical nature of the substrate (mixed micelles with surfactant or simple solution). At Triton X-100 levels above the critical micelle concentration (c.m.c.), the kinetic behaviour of the hydrolysis of p-nitrophenyl palmitate in Triton X-100 mixed micelles catalyzed by Candida rugosa lipase was consistent with the Michaelis—Menten rate equation under three different experimental conditions: (i) the molar fraction of substrate held constant and the Triton X-100 concentration varied; (ii) the bulk substrate concentration held constant and the Triton X-100 concentration varied, and (iii) the Triton X-100 concentration held constant and the bulk substrate concentration varied. Kinetic analysis performed in the above conditions revealed that the simple model described by Verger et al. [J. Biol. Chem., 248 (1973), 4023] correctly interprets the kinetic behaviour of the commercial lipase from Candida rugosa used in the study and highlights the advantage that this classic mechanism may have in current lipase modelling in biocatalysis.

The oxidative coupling of methane was carried out over Mg₃ (PO₄)₂ and MgSO₄ in the presence of tetrachloromethane (TCM) in order to compare the catalytic activities, the interaction between TCM and each catalyst and the effect of the nature of the anion. The conversion of methane on the sulphate increased with increase in the partial pressure of TCM and of reaction temperature, while with the phosphate the presence of TCM had little effect under the same conditions as those on the sulphate. With both catalysts the addition of TCM increased the selectivities to ethylene. Relatively large quantities of chlorinated species were detected on the catalyst surface of the used phosphate by XPS, although none were detected by XRD analyses. In contrast, only small quantities of chlorinated species were formed on the sulphate catalyst and magnesia was detected by XRD in the bulk phase of the used sulphate. The interactions between TCM and the catalyst and, in particular, the effect of the nature of the anion are discussed.

Vanadyl complexes anchored to polymers are effective as catalysts in the oxidation of sulfoxide to sulfone by tert-butyl hydroperoxide. To study the effect of ligand bound to vanadium in such catalytic reactions, vanadyl complexes of salicylaldoxime (a), 3-2(thenoyl-1,1,1-trifluoroacetone) (b) and (o-phenylene-bis-salicylimine) (c) were anchored to polymers and the effectiveness of the catalysts in the oxidation of dimethylsulfoxide and diphenylsulfoxide by tert.-butylhydroperoxide was investigated. The order of catalytic activity was a ≈ b > c in both cases. In the homogeneous systems using the same complexes, the order of catalytic activity was found to be b > c > a. The polymeric beads isolated at the end of oxidation reaction were used for successive runs and the catalytic activity was similar in the first three cycles. The results are discussed on the basis of structural features of the ligands and the reactants.

Several organofluorine compounds endowed with unique pharmaceutical activity, such as fluorinated aminoacids, fluorinated arylpropanoic acids, etc. can be conveniently prepared by hydroformylation, hydrocarboxylation and hydroesterification of appropriated olefins containing one or more fluorine atoms in definite positions of the molecule.

Many organic-fluorinated compounds obtained by carbonylation procedures represent very useful intermediates for the synthesis of pharmacologically active molecules, as for instance: fluor-indoles, fluor β-lactams and fluor uracils.