Search

Acylation of anisole is a commercially important reaction in the production of various fine chemicals, agrochemicals, pharmaceuticals and fragrances. Conventionally, it is carried out using the catalysts like AlCl3, FeCl3, ZnCl3, HF, which suffer from major drawbacks such as larger consumption, corrosion and safety issues, waste disposal and the material handling. Hence the conventional catalysts are being replaced with solid acid catalysts like H-Beta, H-ZSM5 to overcome the above drawbacks. In this work, liquid phase acylation of anisole has been carried out employing H Beta, H ZSM-5 and HY catalysts and the process standardization at a macrolevel has been done with reference to parameters like temperature, reaction time, molar ratio of reactants, catalyst nature, Si/Al ratio of catalyst and the catalyst quantity. In addition, catalyst stability was investigated.

In the present work, the stability and regenerability of H-Beta zeolite in toluene mononitration is studied. Nitration of toluene is carried out in batch mode under reflux conditions using various molar ratios of toluene and nitric acid. Semi batch experiments under reflux are also conducted where nitric acid is dosed at predetermined rates to the reaction mixture containing toluene and the catalyst. The catalyst used in semi batch experiments is found to exhibit consistent performance upto three cycles. The possible cause of consistent activity of the catalyst with respect to para-selectivity has been explored. The physico-chemical changes, if any, in the catalyst is examined for structural stability and presence of pore blockages using sophisticated analytical tools like XRD, EDX, FTIR and 27Al MAS-NMR. These studies indicate the commercial potential of cleaner option of replacing sulfuric acid with zeolites in toluene nitration.