Process for the preparation of alkoxyalkanoic acids

Claim 1

A process for the preparation of an alkoxyalkanoic acid of the formula RO(CH 2 CHR'O) n CH 2 CO 2 H wherein R is an alkyl group of from about 1 to about 1000 carbon atoms, R' is hydrogen or alkyl or mixtures thereof (on the individual molecule) and n is an integer of from about 1 to about 1000, which comprises reacting the corresponding alkoxyalkanol with a stable free radical nitroxide having the formula: ##STR16## wherein (1) (a) each of R 1 , R 2 , R 3 and R 4 is an alkyl, aryl or substituted alkyl group having 1 to about 15 carbon atoms, and (b) R 5 and R 6 (i) each is an alkyl group having 1 to about 15 carbon atoms provided that R 1 -R 6 are not all alkyl groups, or a substituted alkyl group having 1 to about 15 carbon atoms wherein the substituent is hydrogen, cyano, --CONH 2 , --OCOCH 3 , OCOC 2 H 5 , carbonyl, alkenyl wherein the double bond is not conjugated with the nitroxide moiety, or --COOR wherein R of the --COOR group is alkyl or aryl, or (ii) together form part of a ring that contains at least 3 carbon atoms and up to two heteroatoms of O or N, (2) the ##STR17## moiety and the ##STR18## moiety individually are aryl, or (3) the ##STR19## moiety and the ##STR20## moiety together form a bicyclic ring with the proviso that the group directly adjacent to the N--O moiety is a bridgehead C--H, or a fully alkylated carbon, in the presence of a chromium (II) salt, a nitrite compound, a highly polar solvent, an oxidant and water, at a temperature in the range of from about 0° C. to about 100° C. and thereafter separating out the alkoxyalkanoic acid.