A process 1 wherein the at least one aromatic monocarboxyclic acid of is selected from the group consisting of: ##STR19## where L is a direct link, O , S , or ##STR20{HEAD ~ ##} where {TAIL ~ p} is 1 or 2, q is 1 or 2, r is 0 or 1, R is a direct link, O , or S , R is a direct link, O , S , CO , SO2 , or C2 , and Q is CO , SO2 or C2 