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Due to the moderate dielectric constant of CXB (ε = 7.9 [2]), PMMA acquires charges that can be screened by the addition of salt (e.g. tetrabutyl ammonium bromide), leading to a very good approximation of colloidal hard sphere. [3]
In the case where the heterochiral complexes ML R L R L S and ML S L S L R are less reactive than the homochiral complexes ML S L S L S and ML R L R L R, a kinetic behavior similar to the ML 2 model is observed (Figure 9). However, a substantially different behavior is observed in the case where the heterochiral complexes are more reactive than
3 I. (Similar procedures can give cis,trans isomers of 1,4-cyclooctadiene and 1,5-cyclooctadiene). [2] In addition, a photochemical method exists for the direct cis–trans isomerisation. Although this equilibrium strongly favours the more stable cis form, the reaction can be driven towards the trans form by trapping with silver ions. [11] [12]
A single-displacement reaction, also known as single replacement reaction or exchange reaction, is an archaic concept in chemistry.It describes the stoichiometry of some chemical reactions in which one element or ligand is replaced by atom or group.
The sulfur radical was found to be more reactive (6*10 8 vs. 1*10 7 M −1.s −1) and less selective (selectivity ratio 76 vs 1200) than the carbon radical. In this case, the effect can be explained by extending the Bell–Evans–Polanyi principle with a factor δ {\displaystyle \delta \,} accounting for transfer of charge from the reactants ...
Living cationic polymerization is a living polymerization technique involving cationic propagating species. [1] [2] It enables the synthesis of very well defined polymers (low molar mass distribution) and of polymers with unusual architecture such as star polymers and block copolymers and living cationic polymerization is therefore as such of commercial and academic interest.
A corollary of the effect is to explain the existence of one-way enzymes that are much more effective catalysts for one direction of reaction than the other. For example, the limiting rate in the forward direction of the reaction catalyzed by methionine adenosyltransferase is about 2 × 10 5 times higher than it is for the reverse reaction. [5]
Additionally, the reactivity of two series of ketones are in the orders Cl 3 CCOCH 3 > CH 3 COCH 3 > C 6 H 5 COCH 3 and cyclohexanone > cyclopentanone > cycloheptanone > cyclooctanone. [7] [8] These orders of reactivity are the same as those observed for reactions that are well established as proceeding through nucleophilic attack on a carbonyl ...