Donor hydrogenation product yields

In the four components, i.e., TiOj/MV /electron donor/bacterial cells, each of the last three components has its own specific function and each facilitates the other s role, thereby enhancing the yield of hydrogen production. It was found that with sensitized TiO, there is a higher amount of hydrogen production than with the naked TiO. Among the sensitizers used, Rhodamine B and Ru(bpy)3 " exhibited higher efficiencies compared with other sensitizers, as well as other methods of sensitization (2 and 3) (Gumnathan, 2000). 

The highest ttn published to our knowledge so far for chemzymes (in the sense of polymer-enlarged chemical catalysts) is found in the transfer hydrogenation process catalyzed by Gao-Noyori s catalyst bound to a siloxane polymer (Fig. 3.1.3, 4) [13, 14]. In this transfer hydrogenation acetophenone is reduced to (S)-phenyl-ethanol using isopropanol as hydrogen donor. The product is produced in a CMR with 91% ee at a space-time yield of 578 g L d the ttn for the catalyst is 2633. 

The carbocation subsequently is quenched by a hydride donor or hydrogen to yield the saturated product. A sufficient stability of the intermediate carbocation and proper choice of the hydrogenating reagent pair are prerequisites to a successful ionic hydrogenation. 

One of the methods used in the production of liquid fuels from coal is to heat coal in the presence of solvents in order to dissolve and stabilize low molecular weight fragments. Many studies (1-6) have been devoted to elucidating the chemical mechanism of product formation in hydrogen donor and non-donor solvents. In most of these studies, the time dependence of the product yield was used as a measure of the rates of reaction, or the product yield was correlated with the solvent, the rank of the coal or other properties of the coal. In order to gain a better understanding of the nature of the coal-solvent interactions, we... 

Compound reduced Hydrogen donor Product Yield, %... 

Photochemical Hydrogen Production using Cadmium Sulfide Suspensions in Aerated Water Cysteine or EDTA used as electron donor and platinized samples used as in Entry 5. The H2 yield only marginally reduced in the presence of O2. 492... 

Data on the photocatalytic hydrogen-production cycles in systems including different macrobicyclic complexes are systematized in Ref. 384. [Ru(bpy)3], [Ru(4,4 -Me2bpy)3] +, and [Ru(bpy)2L] (L is a carboxylic acid or its derivatives) cations were chosen as sensitizers and EDTA as a sacrificial electron donor. Dependences of hydrogen-production rates and hydrogen yields on the redox potential magnitude, as well as on the concentrations of ETA, sensitizer, and platinum catalyst the irradiation time and the pH of the solution have been studied. 

Transfer hydrogenation is a reaction in which hydrogen is catalytically transferred from a suitable hydrogen donor (DH2) to a reducible substrate (S) yielding the hydrogenated product (SH2) and the oxidized form of the donor molecule (D) [236-238]. 

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