View all references and large excess of polyphosphoric acid[17]17. Learmonth , DA 2002. Synth. Commun., 32: 2757 [Taylor & Francis Online], [Web of Science ®] View all references were needed to complete the reactions. We would like to decrease amounts of catalysts and not to use organic solvents in our microwave assisted Friedel-Crafts acylation, because chemical wastes should be as little as possible from the environmental and economic ...