2,4-Dichlorotoluene → Toluene chlorotoluene

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Reaction Steps

This example shows the utility of sulfided noble metals as a dehalogenation catalyst for substituted chlorobenzenes. The catalyst used was 0.5% palladium on 1/8" alumina. 2,4-Dichlorotoluene was used as the feed and the feed rate was maintained at about 1.25 g/min. The dehalogenation reaction catalysed by non-sulfided palladium at a temperature of 300° C. was found to be very vigorous. Up to 81% toluene was formed during such dehalogenation, yielding a mole ratio of toluene-chlorotoluene of 4.24. When the dehalogenation was catalysed by a sulfided palladium, the reaction rate was reduced considerably and the selectivity to chlorotoluene was improved. Only 41% toluene was found in the dehalogenated product which corresponded to a toluene/chlorotoluene mole ratio of 1.19. Thus sulfided palladium was found to be effective in improving selectivity to substituted chlorobenzene.

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