Organic compositions

Compounds of formula I:

• ##EQU2## wherein, n is an odd integer of 3 to 13 and
• R is hydrogen, alkyl of one to 16 carbon atoms, alkenyl of two to 16 carbon atoms, alkynyl of two to 16 carbon atoms, cycloalkyl of four to eight carbon atoms, aryl of six to 14 carbon atoms, aralkyl of seven to 15 carbon atoms, said cycoalkyl, aryl or aralkyl being optionally sustituted by one or more halogen, alkyl, alkoxy, aryl, aralkyl, aryloxy or aralkoxy groups, with the proviso that each compound of formula I contains at least 15 carbon atoms in the molecule.