Removal of free acids from heavy alkylbenzene sulfonic acid by a novel three-step method

Excessive amounts of free acids will significantly reduce the quality of heavy alkylbenzene sulfonic acid and its downstream products. To get rid of the excess free acids in heavy alkylbenzene sulfonic acid, a novel three-step deacidification technique called barium salt neutralization method was developed with the aware of “process intensification” in this work. Various factors affecting the deacidification process were thoroughly studied. Results show that using this deacidification method, the free acids content in heavy alkylbenzene sulfonic acid can be reduced from 1.5% to less than 0.1% at the producing condition of room temperature, atmospheric pressure, reusable green solvent, and short time. The free acids removal rate and recovery rate of feed can reach to 96.7% and 95.3%, respectively. It has been demonstrated that the barium salt neutralization method is an effective way to lower the amount of free acids in heavy alkylbenzene sulfonic acid, and can be readily turned into practical applications.