Relations between the structure of quaternary alkyl ammonium salts and their biodegradability

Abstract

Oxidation rates of various quaternary alkyl ammonium salts by a microbial culture grown on hexadecyltrimethylammonium bromide are used to assess the biodegradability. On the basis of these oxidation rates and additional closed bottle test results the following relationships between the biodegradability and the structure of quaternary alkyl ammonium salts have been formulated: • - the resistance to biological degradation is to a small extent caused by an increasing length of the alkyl chain; • - the resistance increases strongly with the number of long alkyl chains linked to the nitrogen atom. In summary, a closely packed nitrogen atom results in “inherently” biodegradable quaternary alkyl ammonium salts.