Some esters of mono-, di-, and tricarboxystearic acid as plasticizers: Preparation and evaluation

Methyl mono-, di-, and tricarboxystearates were prepared by either a two-step hydroformylation-oxidation reaction or direct hydrocarboxylation of unsaturated vegetable oil methyl esters. Procedures were developed for preparing alkyl dicarbomethoxy-, dicarboethoxy-, and dicarbobutoxystearates. These triesters, along with some di- and tetraesters from mono- and tricarboxystearic acids, were evaluated as primary plasticizers for polyvinyl chloride (PVC). Except for butyl carbobutoxystearate, the esters were compatible at the 32% level and had properties equal or superior to those of dioctyl phthalate. Methyl and butyl diesters of carboxystearic acid had undesirable migration and volatility properties. The migration and volatility properties of some tri- and tetraalkyl esters were equal to or better than the controls. Of the various esters tested, methyl dicarbomethoxystearate containing 13–49% methyl tricarbomethoxystearate was an efficient plasticizer for PVC at the 32% level.