Production of benzaldehyde: a case study in a possible industrial application of phase-transfer catalysis

The conventional method of producing benzaldehyde by direct oxidation of to luene has a major drawback: low conversion to achieve high selectivity. Pha se-transfer catalysis (PTC) may be used as an alternative route for benzald ehyde production. In the present study, routes to produce benzaldehyde from benzyl chloride in the Liquid phase by using PTC have been examined based on the kinetic data obtained. Using the results of this study and the avail able information on the conventional route, process design simulations have been carried out for all the routes. While PTC-based processes offer advan tages, the study shows that the conventional route appears to be the prefer red one for this relatively large-scale organic intermediate with current c onversions, selectivities, and chemical costs. However, even minor improvem ents in one or two PTC steps can greatly enhance the prospects of the PTC r oute. In general, as the processes get increasingly chemistry intensive, th e PTC route becomes increasingly the preferred candidate. (C) 2001 Elsevier Science B.V. Ah rights reserved.