Prof. L.K. Doraiswamy spent significant time at Iowa State University to further the knowledge in the area of phase transfer catalysis (PTC). PTC reactions were reasonably well known when he started working in this area. A few of his graduate students (with speaker being one of them) studied chemical engineering aspects of phase transfer catalysis and developed several mathematical models to describe the mass and heat transfer processes involved. In this talk, Prof. Doraiswamy’s critical contributions in PTC will be highlighted with a review of current applications in the pharmaceutical industry.