Synergism effects

The higher activity observed when working with reduced Cu/MgO suggests that there is a synergic effect between the support and the metallic phase, while the MgO may play a major role in determining the product s stereochemistry. 

It is interesting to note that, as far as superactivation is concerned, a hierarchy effect, rather than a simple additive or synergic effect, is found,127 i.e., the activators act in the order Sn, Ga, In. Hence, when Sn is present, the superactivation occurs as though the other elements were not present at all. 

The removal of H2S in the gas phase was found to proceed with good results when composites of Ti02 and SiMgO materials were employed, owing to the synergic effect of the photocatalytic activity of the former material and the adsorptive properties of the latter for S02 [134]. 

The same group, in a previous work, reported on the realization of a hybrid anode electrode [197]. An appreciable improvement in methanol oxidation activity was observed at the anode in direct methanol fuel cells containing Pt-Ru and Ti02 particles. Such an improvement was ascribed to a synergic effect of the two components (photocatalyst and metal catalyst). A similar behavior was also reported for a Pt-Ti02-based electrode [198]. Another recent study involved the electrolysis of aqueous solutions of alcohols performed on a Ti02 nanotube-based anode under solar irradiation [199]. 

The effectiveness of zeolites in catalysis and separation can often be improved by the textural and chemical properties of the matrices in which they are imbedded. Chitosan gels issued from renewable resources are already used as supports for the preparation of heterogeneous catalysts in the form of colloids, flakes or gel beads [1, 2], In this study we present several methods for the incorporation of zeolites in chitosan matrices and characterize the synergic effect of the components on the properties of the composite. 

Microwave heating has already been used in combination with some other (unconventional activation processes. Such a combination might have a synergic effect on reaction efficiencies or, at least, enhance them by combining their individual effects. Application of MW radiation to ultrasound-assisted chemical processes has been recently described by some authors [18, 19]. Mechanical activation has also been successfully combined with MW heating to increase chemical yields of several reactions [1]. 

Synergic effect of calcium oxide and iron (III) oxide on the dechlorination of hexachlorobenzene ... 

Rh, are the base of active catalysts for CO hydrogenation and the hydroformylation of olefins. The presence of several promoters modifies their catalytic behavior and synergic effects on the base-metal have been observed Table 8.5 illustrates several examples in which homonuclear or heteronuclear carbonyl compounds have been used in the preparation of Co- or Co-Rh-based catalysts for the CO hydrogenation and/or hydroformylation reactions. 

In most cases two different additives are used, one acting as an internal filter or excited state quencher and the other one being a scavenger of free radicals. These two additives have a synergic effect, that is they are much more effective together than either of them separately. 

NaN03 increased DRu further while HDBP had a synergic effect on Ru(NO) 3+ extraction by TBP. This latter observation indicates another mechanism by which ruthenium may be extracted into and retained by the organic phase. 

Tokudome, Y., and K. Sugibayashi. 2003. The synergic effects of various electrolytes and electroporation on the in vitro skin permeation of calcein. J Control Release 92 (l-2) 93. 

In the absence of an aqueous phase, the increased >M(III) were attributed to the synergic effect brought about by H2MEHP DAm measured in a mixture... 

E. J. Baerends and A. Rozendaal, in Quantum Chemistry The Challenge of Transition Metals and Coordination Chemistry, A. Veillard, Ed., Reidel, Dordrecht, 1986, pp. 159-177. Analysis of o-Bonding, it-(Back) Bonding and the Synergic Effect in Cr(CO)6. Comparison of Hartree-Fock and Xa Results for Metal-CO Bonding. 

Lithium + succinylcholine —> prolonged muscle paralysis synergic effect of the drugs at the neuromuscular junction. 

The difficulty in finding a correlation between file results of chemical analyses and ecotoxicological assays may have been due to antagonistic and synergic effects... 

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