Solid/liquid phase-transfer catalysis. Some models and solvent influence

Kinetics of ‘initial burst’ in the solid–liquid phase‐transfer catalysis. Nucleophilic substitution of 2‐octyl mesylate with potassium bromide

“…13 This approach is based on the continuous deceleration of the reaction due to the growing contribution of diffusion through the solid product 'crust,' which constantly accumulates over the reacting particles. Recently, this approach has also been applied to describe s/l PTC kinetics, 11 although the reported case is not identical with ours. In the topochemical model, the amount of 'crust' grows constantly, so the reaction does not become zero-order.…”

“…The IB kinetics have not been studied with respect to PTC before, although there are papers reporting on similar kinetic features in analogous systems. 11,12 This investigation was directed towards a more detailed study of such kinetics in the reaction of 2-octyl mesylate with solid KBr [Eqn. (1)].…”

Recent advances in the syntheses, transformations and applications of 1,1-dihalocyclopropanes

“…49 Wang and co-workers found that the rate of dichlorocyclopropanation of 1,7-octadiene follow a pseudo first order under phase transfer conditions with high or low alkaline concentration. 52 The kinetics of chain chlorination of cyclopropanes was also studied. The kinetics of cyclopropanation of styrene under phase transfer catalysis was investigated and the results showed that formation of a film in a liquid-liquid system and formation of a crust of a product on the surface of the solid reactant in a solid-liquid system make significant contribution to the observed kinetics.…”

Highly Regioselective Friedel–Crafts Reactions of Electron‐Rich Aromatic Compounds with Pyruvate Catalyzed by Lewis Acid‐Base: Efficient Synthesis of Pesticide Cycloprothrin

“…The addition of 7 to dichlorocarbene generated from chloroform in the presence of 50% sodium hydroxide and the phase-transfer catalyst triethylbenzylammonium chloride gave gem-dichlorocyclopropanecarboxylate 8 in 65% yield. [11] The addition of dichlorocarbene was induced at 60 8C with extremely exothermic conditions that caused a vigorous reflux of the solvent to give a black tar product. Thus, the research for safe conditions for dichlorocyclopropanation is very important due to the exothermic reaction when the reaction is scaled up to the tons scale.…”