Hydrochloric Acid → p-Toluenesulfonic acid

Temperature

7.5 °C

A mixture of 15.0 g (47.5 mmol) PRON-HCl, 170 mL MTBE and 20 mL water is cooled to 5 to 10° C. in a 250 mL vessel. After addition of 12.8 g of a 20% NaOH solution the mixture is stirred for further 15 min, while phase separation occurs. The organic phase is washed with water (60 mL) and the aqueous phase is extracted with MTBE (2×50 mL). The combined organic phases are cooled to below 10° C. and within 15 min a suspension of 8.6 g (45 mmol) p-toluenesulfonic acid monohydrate in 400 mL MTBE is added. An oily suspension is formed. The volume of the solvent is reduced to approximately the half. The reaction mixture is heated under reflux and 250 mL heptane are added. The mixture is cooled to RT and stirred for 30 min. The solid matter is filtered off, washed with MTBE (2×60 mL) and dried in vacuo at 50 to 55° C. affording 14.3 g of product (tan solid matter).

1. washThe organic phase is washed with water (60 mL)
2. extractionthe aqueous phase is extracted with MTBE (2×50 mL)
3. temperatureThe combined organic phases are cooled to below 10° C. and within 15 min
4. additionis added
5. customAn oily suspension is formed
6. temperatureThe reaction mixture is heated
7. temperatureunder reflux
8. temperatureThe mixture is cooled to RT
9. stirringstirred for 30 min
10. filtrationThe solid matter is filtered off
11. washwashed with MTBE (2×60 mL)
12. customdried in vacuo at 50 to 55° C.

ORD record

ord-dc28fb3962d94168a126f68256dc1c5d

Source dataset

uspto-grants-2011_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07973182B2