homogeneous catalyst


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homogeneous catalyst

A catalyst that exists in the same phase as the chemicals it influences and the reactions it produces. See: phase
See also: catalyst
References in periodicals archive ?
Common examples of homogeneous catalysts includes: polymolybdates like phosphomolybdic acid, ammonium heptamolybdate, etc.
Pseudo-first order reaction rate constants ([k.sup.1]) and squared correlation coefficients ([R 2) for the degradation of BA with homogeneous catalysts No catalyst [Mn.sup.2+] [Ni.sup.2+] [k.sup.1] [10.sup.-4] [s.sup.-1] 12.2 11.5 12.5 [R.sup.2] 0.964 0.994 0.993 [Mo.sup.6+] [Fe.sup.2+] [Cu.sup.2+] [k.sup.1] [10.sup.-4] [s.sup.-1] 14.8 15.4 18.2 [R.sup.2] 0.995 0.956 0.997
For this reason, the highly active homogeneous catalysts which can be easily recycled and reused are highly attractive in this reaction.
The book describes several heterogeneous catalysts currently in use, then shows how nanoscience can be used with artificial homogeneous catalysts. Some chapter topics include the structure and reactivity of single and multiple sites on heterogeneous and homogeneous catalysts, the relationship between catalysis with transition metal complexes and catalysis by nanoparticles, synthetic catalysts of nanometric dimensions, and nanostructured photovoltaic materials for solar energy conversion.
However, the removal of homogeneous catalysts is very time-consuming and expensive, which creates a big problem for pharmaceutical companies," Zubarev added.
Currently, heterogeneous catalysts have been developed for use in a transesterification reaction for biodiesel production due to the problems of homogeneous catalysts in terms of water treatment and the nonreusability of the catalyst.
Sanford, "Heterogenization of homogeneous catalysts in metal-organic frameworks via cation exchange," Journal of the American Chemical Society, vol.
Objective: In the past decade, artificial metalloenzymes (AMs) have emerged as an attractive alternative to the more traditional enzymes and homogeneous catalysts. Such hybrid catalysts result from the incorporation of an abiotic metal cofactor within a macromolecule (protein or oligonucleotide).
The yield of 3,5-diphenyl-4,5-dihydroisoxazole catalyzed by homogeneous catalysts, NaOH, is comparable to the result catalyzed by CaO under the suggested react condition, while the lowest catalytic activity is shown over Na2CO3, only proceed with yield of 21.4% indicating the strong basic sites of CaO is highly active for this reaction.
The problems of homogeneous catalysts in recovering and recycling lead to the loss of metal and ligands and incorporation of impurities in the products [11].
Homogeneous catalysts; activity--stability--deactivation.
These catalysts can now compete more closely with homogeneous catalysts, which industry traditionally uses for reactions that require high selectivity such as those involved in the manufacture of medicines or other fine chemicals," he said.