in order to prepare fluid , storage - stable ampholytic surface - active agents , 1 - hydroxyethyl - 2 - alkyl - 2 - imidazolines having formula , in which r 1 stands for an alkyl residue with 5 to 21 carbon atoms , are quaternated or carboxymethylated with halogenated carboxylic acid salts at a ph range from 7 . 5 to 9 , and at the same time hydrolyzed with aqueous bases , then the ph value of the reaction final products is set between 5 and 7 . ## str1 ##