The prevalence of solvent effects in heterogeneous catalysis in condensed media has motivated developing quantitative kinetic, and their interactions with reaction intermediates and transition states. In an article, 108-47-4, name is 2,4-Dimethylpyridine, introducing its new discovery. Recommanded Product: 108-47-4
Heats of ionization by thermometric titration for a series of bases (or acids) can be used to compare solid acids (or bases) with liquid analogues bearing the same functionalities in homogeneous solutions.The method is demonstrated for Broensted acids by reacting a series of substituted nitrogen bases with solutions of p-toluenesulfonic acid (PTSA) in acetonitrile and with suspensions of the microporous polymeric arylsulfonic acid resin-Dowex 50W-X8 in the same solvent.Under well-controlled anhydrous conditions there is a good correlation (r=0.992) between the heats of reaction of the bases with the homogeneous and heterogeneous acid systems, but the homogeneous system gives a more exothermic interaction by 3-4 kcal/mol for a series of 29 substituted pyridines, anilines, and some other amines.This difference may be attributed to homohydrogen bonding interactions between excess acid and sulfonate anion sites which are more restricted geometrically in the resin than in solution.Other factors which affect the enthalpy change for the acid-base interaction are the acid/base ratio, the water content of the sulfonic acid, the solvent, and the resin structure (e.g., microporous vs. macroporous).Steric hindrance in the base not differentiate solid from homogeneous acid.In addition to the use of titration calorimetry, heats of immersion are reported for the Dowex-arylsulfonic acid resins and the Nafion-perfluorinated sulfonic acid resin in a series of basic liquids.The results are compared with each other and with those from a previous study of several varieties of coal.
In conclusion, we affirm that quantitative kinetic descriptions of catalytic behavior continue to serve as an indispensable tool to navigate research efforts intended to model. If you are interested in 108-47-4, you can contact me at any time and look forward to more communication. Recommanded Product: 108-47-4
Reference：
Chiral nitrogen ligands in late transition metal-catalysed asymmetric synthesis—I. Addressing the problem of ligand lability in rhodium-catalysed hydrosilations,
Nitrogen-Containing Ligands for Asymmetric Homogeneous and Heterogeneous Catalysis