Tsutomu Osawa

Progress of enantio-differentiating hydrogenation of prochiral ketones over asymmetrically modified nickel catalysts and a newly proposed enantio-differentiation model

This article reviews the enantio-differentiating hydrogenation of various prochiral ketones over asymmetrically modified Ni catalysts. Development from the discovery to the state of the art of the modified Ni catalyst is surveyed. Understanding and interpretation of this catalyst is discussed and new enantio-differentiation models are proposed.

Application of an in situ modification of nickel catalysts to the enantio-differentiating hydrogenation of methyl acetoacetate

Abstract In situ modification (( R , R )-tartaric acid and NaBr were directly added to the reaction media) of fine Ni powder (FNiP) and reduced Ni catalysts was applied to the enantio-differentiating hydrogenation of methyl acetoacetate (MAA). The high optical yield of 89% was attained by the reduced Ni catalyst. This is the highest value reported so far for the hydrogenation of methyl acetoacetate using the in situ modification. The addition of a small amount of NaBr to the reaction media increased both the optical yield and hydrogenation rate, while the hydrogenation rate decreased with the addition of NaBr to the modification solution for the conventional modification method. NaBr added to the reaction media for the in situ modification would have both of the following roles: (i) Na + increased the optical yield and the hydrogenation rate; and (ii) Br − increased the optical yield and decreased the hydrogenation rate.

High durability of asymmetrically modified nickel catalysts prepared by in situ modification

Abstract The in situ modification of a reduced Ni catalyst at the first run showed a high durability for the repeated use with high optical yields in the enantio-differentiating hydrogenation of methyl acetoacetate. Reduced Ni from Ni oxide and fine Ni powder were the best materials in comparison with Raney Ni. For attaining high optical yields and high durability, in situ modification and a Ni surface suitable for the enantio-differentiating hydrogenation are necessary. One of the reasons for the low durability of the conventional pre -modified Ni with repeated use would be the desorption of tartaric acid from the catalyst surface during the hydrogenation reaction.

Enantio-differentiating hydrogenation of methyl acetoacetate over tartaric acid-NaBr-modified supported nickel catalyst prepared from nickel acetylacetonate

Abstract Supported nickel catalysts were prepared from nickel acetylacetonate, and then modified in a solution containing tartaric acid and sodium bromide. The enantio-differentiating hydrogenation of methyl acetoacetate was carried out over this catalyst. The effects of the preparation variables of the supported nickel catalysts on the optical yield and the effects of the conditions for the nickel surface modification on the optical yield were examined. The catalysts were also characterized by XRD and TEM. The maximal optical yield of 87% was attained when crystallized α-alumina (sumico rundum) was used as a support.

Enantio-differentiating hydrogenation of methyl acetoacetate over fine nickel powder with in situ modification

Enantio-differentiating hydrogenation of methyl acetoacetate (MAA) was carried out using fine nickel powder (FNiP) by adding tartaric acid (TA) and sodium salts to the reaction media (in situ modification) instead of using a conventionally modified nickel catalyst. This catalyst prepared by the in situ modification gave an optical yield up to 79%.

Acinetobacter sp. Ud-4 Efficiently Degrades Both Edible and Mineral Oils: Isolation and Characterization

A novel Acinetobacter strain, Ud-4, possessing a strong capacity to degrade edible, lubricating, and heavy oil was isolated from seawater in a fishing port located in Toyama, Japan. It was identified by morphological and physiological analyses and 16S rDNA sequencing. This strain could utilize five types of edible oils (canola oil, olive oil, sesame oil, soybean oil, and lard), lubricating oil, and C-heavy oil as the sole carbon source for growth in M9 medium. The strain grew well and heavily degraded edible oils in Luria–Bertani medium during a 7-day culture at 25°C; it also degraded all kinds of oils in artificial seawater medium for marine bacteria. Furthermore, this strain was capable of degrading almost all C10–C25 n-alkanes in C-heavy oil during a 4-week culture. Oligonucleotide primers specific to two catabolic genes involved in the degradation of n-alkanes (Acinetobacter sp. alkM) and triglyceride (Acinetobacter sp. lipA) allowed amplification of these genes in strain Ud-4. To our knowledge, this is the first report on the isolation of a bacterium that can efficiently degrade both edible and mineral oils.

Highly efficient enantio-differentiating hydrogenation over an ultrasonicated raney nickel catalyst modified with tartaric acid

A tartaric acid–NaBr-modified Raney nickel catalyst prepared from ultrasonicated Raney nickel showed excellent enantio-differentiating and hydrogenating activity in the hydrogenation of a series of 3-oxoalkanoate and 1,3-diketones.

Study of the parameters controlling the enantio-differentiating ability of asymmetrically modified solid catalysts for the hydrogenation of γ-ketoesters

The enantio-differentiating hydrogenation of γ-ketoesters was carried out over asymmetrically modified solid catalysts. The parameters affecting the enantiomer excess (ee) were investigated and the results were compared with those of the hydrogenation of methyl acetoacetate and 2-octanone reported in the literature. The highest value of enantiomer excess of 51% was attained for the hydrogenation of methyl 4-oxopentanoate over a tartaric acid (TA)-NaBr-modified reduced nickel catalyst prepared from nickel oxide. The amount of NaBr in the modification solution needed to be optimized according to the manufacturers of the nickel oxides. The addition of an appropriate amount of carboxylic acid to the reaction media increased the enantiomer excess of the hydrogenated products.

Non-solvent hydrogenation of solid alkenes and alkynes with supported palladium catalysts

Abstract The non-solvent hydrogenation of solid alkenes and alkynes was investigated using supported palladium catalysts. trans-Stilbene and carboxylic acids with α,β-CC bonds were employed as the alkene-type substrates for the non-solvent hydrogenation. Their hydrogenation proceeded over a Pd/SiO2 catalyst at room temperature in a hydrogen stream. The hydrogenation rate of the trans-stilbene under the non-solvent conditions was lower than the hydrogenation in tetrahydrofuran (THF). The non-solvent hydrogenation of the CC bond in diphenylacetylene or phenylpropiolic acid proceeded over a Pd/C catalyst more smoothly than their hydrogenation in THF. There was a close relation between the melting points of the substrates or the products and the yields of the non-solvent hydrogenation. This relation suggested that the smooth non-solvent hydrogenation of the substrates with CC or CC bonds proceeded in the fused state.

Enantio-differentiating hydrogenation of 3-alkanones with asymmetrically modified fine nickel powder

The enantio-differentiating (e.d.) hydrogenation of 3-alkanones was carried out over a tartaric acid-NaBr-modified nickel catalyst. An optical yield of 44% was attained in the hydrogenation of the 3-alkanones after an intensive investigation of the catalyst preparation conditions and hydrogenation conditions. The following points were the special features of the hydrogenation of the 3-alkanones. (i) Fine nickel powder was a better source of the e.d. catalyst than Raney nickel which was a suitable source of the e.d. catalyst for β-ketoesters and 2-alkanones. (ii) The addition of a highly bulky carboxylic acid such as 1-methyl-1-cyclohexanecarboxylic acid or 1-adamantanecarboxylic acid was necessary for attaining the high optical yield. (iii) The optimal hydrogenation temperature was 100°C. The differentiation between the ethyl and other alkyl groups (3-alkanones) was much more difficult than that between the methyl and other alkly groups (2-alkanones). However, tartaric acid-NaBr-modified fine nickel powder was a unique catalyst giving good optical yield in the enantio-differentiating hydrogenation of the 3-alkanones.