Carbonic Acid Esters

Abstract

Although the microbicides described in this section all belong to the same substance class, namely to the acid esters, their antimicrobial activity is based on different mechanisms of action. The halogen containing esters (Sections 7.1–7.6) and dimethyl dicarbonate (Section 7.7) are substances with electrophilic character, a character which enables them to react with nucleophilic groups of the microbial cell and which equips the substances with a wide spectrum of antimicrobial effectiveness. The electrophilic character of the halogenated esters mentioned here is reduced due to the fact that the substances are bearing an activated halogen group in the α-position to an electronegative group (see Fig. 34, page 357). Bromo compounds are preferred, because due to the average electronegativity of the bromo atom in comparison to other halogen atoms (for scale of electronegativity values of halogen atoms see Table 71) these compounds are not too stable (not persistent) but also not too reactive (unstable), so that they are preferably used as slimicides not causing waste problems.

Sources for toxicity data, if not otherwise indicated: Registry of toxic effects of chemical substances (1990). Department of Health and Human Services, Cincinnati, USA. Lexikon der Hilfsstoffe für Pharmazie, Kosmetik und angrenzende Gebiete (1989), Ed. H P. Fiedler, Editio Cantor, Aulendorf Germany. Product information and safety data sheets of microbicide suppliers. All indications are given in good faith and conscience. This also applies for the ’maximum working place concentrations’ (MWC), the ’acceptable daily intake’ (ADI) values and to the data with regard to ecotoxicity and biodegradability of microbicides which, as far as accessible, were also incorporated.