Sulfuric Acid → 2-Isopropylaminoethanol sulfate

In a 50-ml three-necked flask, 1.01 g (10 mmol) of sulfuric acid (97%) was diluted with 1 g of water, and the resulting dilution was ice-cooled. A mixture of 1.03 g (10 mmol) of 2-isopropylaminoethanol and 1 g of water was slowly dropped into the cooled dilution. After completion of the dropping, the resulting mixture was warmed to room temperature and 10 ml of toluene was added thereto. The mixture thus obtained was dehydrated by heating with vigorous stirring after attaching a Dean-Stark trap to the flask. The mixture was heated and stirred for 4 hours until a theoretical amount of water was removed. Then, the reaction was continued for another 1 hour. After a large portion of the toluene was removed by decantation, the residual toluene was distilled off under reduced pressure to obtain a crude product of 2-isopropylaminoethyl hydrogensulfate, the desired compound, quantitatively.