wherein R is an alkyl group with from about 1 to about 50, such as from about 5 to about 35 or from about 6 to about 28 carbon atoms, x is an integer of from about 1 to about 50, such as from about 5 to about 25 or from about 9 to about 13, y is 1 or 2, and z is an integer of from about 1 to about 50, such as from about 5 to about 25 or from about 9 to about 13; and those available from PETROLITE