5 carbon atoms and containing one or more etheric oxygen atoms; each occurrence of the subscripts, d, m, n, o, and p independently is an integer wherein d is from 2 to 6, more specifically 2 or 3 and still more specifically 2; m is from 0 to 20; n is specifically from 0 to 18; o is from 0 to 20; p is from 0 to 20; with the proviso that m+n+o+p is equal to or greater than 2.