ither straight-chain or branched), or a haloalkyl group having 1 to 5 carbon atoms (either straight-chain or branched); and p is zero or an integer of 1 or more, preferably 3 or less, a compound of the formula: ##STR10## wherein R7 is a straight-chain, branched or cyclic alkyl group having 1 to 10 carbon atoms, a trifluoromethyl group, a phenyl group or a tolyl group; R8 and R9 are independently a