removing tsa and dsa from the solvent by vacuum stripping or distillation a solvent with a low vapor pressure with respect to the vapor pressure of dsa and tsa will facilitate vacuum stripping of the dsa and tsa from the reaction solvent and collecting the dsa and tsa products a solvent with a high vapor pressure with respect to dsa and tsa will also facilitate removal of the solvent from the dsa and tsa leaving a concentrated dsa and tsa product in a storage vessel that will not collect the lower boiling higher vapor pressure solvent the dsa and tsa products collected may then be further purified by standard techniques such as those disclosed herein and in the literature suitable solvents are solvents that are aprotic non acidic lewis acidic and solvents that do not form strong hydrogen bonds n u2014 h a source of hydrogen bonding preferred solvents are selected from the group consisting of high boiling point mono oxygenated ethers non limiting examples are r u2014 o u2014 r u2032 r u2550 r u2032 and r u2260 r u2032 wherein r and r u2032 are linear branched or cyclic alkyl groups mixtures of the solvents are suitable in the present inventive process the boiling point and therefore vapor pressure of preferred solvents would be either high or low relative to tsa in examples solvents were selected that had at least about a 1 10 vapor pressure ratio solvent tsa relative to.