a value of 0 or 1, M is an alkali metal, and R.sup.1 is an organic group selected from one ofthe following groups:(i) a linear or branched, alkyl or alkenyl group having 8 to 36 carbon atoms,(ii) an alkylphenyl group having an alkyl group of 4 to 14 carbon atoms,(iii) a polyoxyalkylene alkyl, alkenyl or alkylp