Catalysis Today, Vol.60, No.3-4, 263-273, 2000
Alkylation of hydroquinone with methyl-tert-butyl-ether and tert-butanol
The alkylation of hydroquinone yields industrially important compounds, amongst which tert-butylhydroquinone is a very important precursor for its use in pharmaceuticals and in developing photographic plates. Twenty per cent (w/w) dodecatungstophosphoric acid supported on K10 montmorillonite clay (DTP/K10) was found to be a very efficient and novel catalyst in comparison with several others for alkylation of hydroquinone with different alkylating agents such as methyl-tert-butyl-ether (MTBE) and tert-butanol at 150 degrees C in an autoclave. A summary of characterisation of DTP/K10 is provided and related to the activity. Various reaction parameters were also investigated and a kinetic model was built. The rate of alkylation with MTBE was much faster than that with tert-butanol. The reaction follows a typical second order kinetics at a fixed catalyst loading with weak adsorption of both the species. The energy of activation was found to be 19.34 kcal/mol.
Keywords:alkylation;hydroquinone;methyl-tert-butyl-ether;tert-butanol;2-tert-butylhydroquinone;2,5-di-tert-butylhydroquinone;heteropolyacids;catalysis;dodecatungstophosphoric acid