SYNTHESIS AND PRELIMINARY EVALUATION OF ARYL ARENESULFONATE ESTERS ASPOTENTIAL INTERMEDIATE TEMPERATURE FLUIDS

The synthesis and preliminary evaluation of sixty aryl arenesulfonate esters for potential use as intermediate temperature lubricant fluids (225-300 degrees C) is described. These compounds were readily accessi ble synthetically from the reaction of phenols and arenesulfonyl chlor ides. This class appeared to exhibit good methanolytic stability for e xtended periods under neutral or acidic conditions, even when heated a t reflux in methanol. However, methanolysis occurred readily under bas ic conditions, particularly in the presence of electron-withdrawing su bstituents. Many of the aryl arenesulfonates studied were fluids at am bient temperature, but no obvious correlations between structure and f luidity could be discovered. Monosulfonates had a greater likelihood o f being fluids than disulfonates. Also, all of the monosulfonates stud ied which were based on 4-phenoxybenzenesulfonic acid were fluids at a mbient temperature. Aryl arenesulfonates as a class were, in general, significantly more oxidatively stable than a leading commercial pentae rythritol ester fluid, as determined by pressure differential scanning calorimetry (PDSC). Fluoro substitution (F, CF3, CF3O) seemed to enha nce oxidative stability. However, the PDSC data did not lead to the id entification of any obvious trends or correlations between structure a nd oxidative stability.