Francois Metz

Bismuth (III) salts in friedel-crafts acylation

Publisher Summary This chapter illustrates that while bismuth chloride is an efficient catalyst for the aromatic ether acylation by acid chlorides or anhydrides, it is not strong enough to carry out the acylation of non activated aromatics. However, the potential of using a wide range of Bi salts as catalysts, in particular the oxide, the oxychloride and the carboxylates, all non hygroscopic compounds, offers advantages, and is indicative of the great versatility of Bi derivatives. Moreover, the Bi salts obtained after hydrolytic workup are directly reusable. The para-selectivity of the described acylations is very high. In the case of the bismuth salt, the ortho effect, with its disadvantages, does not appear. Because the molecular chemistry is well developed, it seems possible to undertake the synthesis and study of the catalytic power of new bismuth derivatives containing suitable ligands to activate the Lewis acidity of this element.

NMR under high gas pressure

Publisher Summary A fine understanding of reaction mechanisms is of crucial importance to the control and optimization of chemical processes. On account of this, various spectroscopic techniques for mechanistic studies and reaction monitoring have been continuously developed. However, in situ analytical techniques still remain rare in the case of reactions involving liquids under high gas pressure, for example reactions in which a gaseous reactant is used (carbonylation, hydrogenation, carboxylation, phosgenation, chlorination,) or reactions performed at high temperatures in closed vessels in which an autogenic pressure results. Among the techniques, high pressure NMR seems the most promising. Although it has the disadvantages of relatively low sensitivity and a long time scale, the multinuclear chemical shifts and couplings can provide detailed structural, kinetic and dynamic information. As a result, this technique has recently been developed.