Solid-liquid reactions Grignard reaction

Liquid-solid reactions (Friedel-Crafts acylations and alkylations, Grignard reactions) 1-5 50-250 250 250... 

In liquid-solid processes reaction takes place between a liquid reactant and an insoluble or sparingly soluble solid which must be finely divided to speed up the process. Another measure to accelerate the process is to use an aqueous solution of a phase-transfer agent (typically a quaternary ammonium salt). The solid can also be a catalyst for reactions between liquid components, e.g. in acylations, carried out both conventionally in the presence of metal chlorides (mostly AICI3) or catalysed by zeolites and Grignard reactions. 

In systems of this kind, because the solid is insoluble, no reaction can occur between A and B in the liquid phase. Hence the component from the liquid phase must diffuse into the solid phase and react there. The most important example of such a system in organic technology is the manufacture of organometallic compounds, for example, the Grignard reagent. We shall discuss the Grignard reaction at some length later in this section. Another example is the production of... 

The simulation of sonochemical effects on liquid-solid reactions is accomplished by a two-center model that allows for mechanically activated areas on a solid with increased reactivity. The parameters have been fitted to experiments and can be used to find suitable reaction parameters as well as a prediction whether or not a given Grignard reaction will perform better under ultrasound activation or not. 

In 1962 Renson et al. reported that a variety of selenol esters can be synthesized by the reaction of the appropriate acyl chlorides with selenols in the presence of pyridine. - Selenols can easily be prepared from elemental selenium and the corresponding Grignard reagents. In addition to simple selenol esters, a,P-unsaturated selenol esters (4) and (5) and o-substituted aromatic selenol esters (6) have been obtained by this method, as shown in Scheme 1. Butyl selenol esters are generally colorless or light yellow liquids, whereas the phenyl or substituted phenyl selenol esters are white solids, which are easily purified by recrystallization. More recently other groups have used Renson s method to synthesize similar selenol esters. " ... 

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