Central African Journal of Public Health

Publisher B.S.

Amulya V., Ramesh A.

M. Oymak M., Uner D.

Publisher B.S.

S. Edake M., D. Samant S.

Nadtochenko V., Nikandrov V., Borisova Y., Nizova G., Aybush A., Kostrov A., Shagadeev I., Lukashov E., Gostev F., Shelaev I., Traore M., Kanaev A., Shuvalov V., Semenov A.

We report on a performance of the photocatalytic solar energy convertors based on mesoporous TiO2 films with immobilized enzymes and membrane pigment-protein complexes of bacterial reaction centers Rhodobacter sphaeroides and Synechocystis sp. PCC 6803 photosystem-I (PS I) using our patented immobilization technique. These semiconductor- enzymes-pigment-protein systems functioned as both the light-harvester and charge separator in photocatalytic and solar cells self-assembled on nanostructured semiconductors. We described our recent patents on different possibilities of electrons photogeneration in the TiO2 conduction band (c.b.) as well as possibilities to use the potential of e- in the TiO2 c.b for the catalytic reduction of H+ to molecular hydrogen and for reduction of NAD+ (NADP+) to NADH(NADPH) by immobilized enzymes. We also report on femtosecond dynamics of charge separation in PS I with relation to these photocatalytic solar energy convertors.

Escriba M., Ibhadon A.

Bozga G., Apan I.T., Bozga R.E.

The paper is reviewing the patents and journal papers treating catalysis and engineering issues involved in the dimethyl ether (DME) production from synthesis gas. The necessary catalysts include components active for the two reactions defining this process: carbon oxides hydrogenation to methanol and methanol etherification to DME respectively. For the first reaction, amongst the dozens of catalytic materials proposed, the largest utilization has the classical methanol synthesis catalyst Cu-ZnO-Al2O3, sometimes modified with ingredients contributing to the increase of the copper dispersion and stability. Good activity and selectivity for methanol etherification have the solid acids with moderate acidity (γ- Al2O3, zeolites, mesoporous materials etc.). An important challenge in the formulation of the bi-functional catalyst and the reactor design is the prevention or limitation of deactivating phenomena: copper sintering, coking of acidic components and metal ions migration. Particularly, a good temperature control is necessary, due to the important overall process exothermicity. Demonstration plants having capacities up to 100 t DME/day, based on tri-phase slurry reactors or jacketed multi-tubular reactors, are already in successful operation. An important drawback of the one-step DME synthesis process is the formation of CO2 as secondary product, difficult to separate from DME mixture. Patented technologies are based on separation by extraction with selective solvents or by refrigeration and distillation. Efficient and environmentally friendly design solutions are integrating the DME synthesis line with hydrocarbon reforming units, recycling and valorizing CO2 byproduct. Studies are also in progress, aiming to develop technologies for DME synthesis by CO2 hydrogenation.

Wang S.

Ouyang L., Da G., Ni J., Xu J., Han Y.

Patel A.

Babu S.A., Anand R.V., Ramasastry S.S.

This review provides insights into the patents available on one of the subfields of organocatalytic reactions, specifically, the Cinchona alkaloids-based organocatalytic reactions, involving asymmetric C-C bond construction. Some of the very important achievements in the asymmetric carbon-carbon bond formation by employing the Cinchona alkaloids- based organocatalysts, one of the privileged classes of asymmetric catalysts, have been accentuated. The Cinchona alkaloids-based enantio- and diastereoselective syntheses of a range of amino acid derivatives, bioactive molecules and various synthetic intermediates with high efficiency are also highlighted.

Bentham Science Publisher B.S.

Sanchez L., Sathicq A., Thomas H., Romanelli G.

The present review focuses on the patented synthetic methods and numerous pharmaceutical applications of 1,4-dihydropyridines. They were originally prepared by the Hantzsch multicomponent reaction, but nowadays there are several new methods. They have improved reaction yield and have reduced the risks of contaminating the environment. These improvements were achieved through the use of different catalytic systems, a variety of reaction solvents, and also some reactions were carried out without either catalyst or reaction solvent.

Tankovsky N., Syrakov E., Zografov N.