Provided are mixtures of 1) compounds of the formula: ##STR00001##
wherein R.sub.1 is a saturated or unsaturated cyclic hydrocarbon optionally substituted with an alkyl and/or an OXO-ester, and R.sub.2 is a C.sub.4 to C.sub.14 hydrocarbyl; and 2) one or more second plasticizers selected from the group consisting of alkyl terephthalates, alkyl phthalates, alkyl benzoate esters, di-benzoate esters, esters of cyclohexane polycarboxylic acids, and dialkyl adipates. Also provided are plasticized polymer compositions containing said mixtures.