Total acidity Applied Chemistry

In industry many selective oxidations are carried out in a homogeneously catalyzed process. Heterogeneous catalysts are also applied in a number of processes, e.g. total combustion for emission control, oxidative coupling of methane, the synthesis of maleic acid from butanes, the epoxidation of ethylene. Here we focus upon heterogeneous catalysis and of the many examples we have selected one. We will illustrate the characteristics of catalytic oxidation on the basis of the epoxidation of ethylene. It has been chosen because it illustrates well the underlying chemistry in many selective oxidation processes. 

The chemistry of bismuth vanadate pigments makes them sensitive to acids. Ho v-ever, tests in which acids were applied to baking finishes under practical conditions have shown that the acid resistance of these pigments is normally comparable to that of a highly stabilized lead chromate. The application of bismuth vanadate pigments in powder coatings and coil-coatings should be tested in customer material, because in such cases - more than in standard liquid paint systems - the suitability depends on the total formulation. 

Sultones are the internal esters of hydroxy sulfonic acids and are the sulfur analogs of lactones. Sultones are demanded scaffolds in medicinal chemistry research. Biological studies on sultones are mainly concerned with their toxicological, skin sensitization, and antiviral activities [20]. Sultones are synthetically useful heterocycles which can react with a variety of compounds to introduce the alkylsulfonic acid function and therefore used as sulfoalkylating agents [21]. There have been several new developments for the synthesis of sultones which have also been applied in the total synthesis of natural products. In recent years, the palladium-catalyzed direct arylation of several aromatics via a C-H bond activation using aryl halides has led to successes. An intramolecular version of this reaction has allowed the synthesis of several biaryls via the formation of five- to seven-membered rings. Thus, the sultones should be synthesized by C-H activation via two pathways (Scheme 4.14). 

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