Optimization of biological-hydroxyapatite supported iron catalyzed methyl oleate synthesis using response surface methodology

Innovative biological-hydroxyapatite (BHAp) derived from Catla catla (abundantly aqua-cultured freshwater species in South Asia) bone was employed to prepare cost-effective, reusable supported iron solid acid catalyst using Fe-2 (SO4)(3).H2O through wet impregnation method employing infrared (IR) irradiation assisted freeze-drying protocol. The catalytic effectiveness was assessed and optimized through response surface methodology (RSM) in synthesis of methyl oleate through esterification of oleic acid with methanol. Catalyst characterization involved TGA, FESEM, EDX, XRD, BET-BJH and FTIR analyses. The catalyst that rendered optimal performance possessed 14.9 m(2)/g specific surface area, 0.0335 cm(3)/g pore volume and 33.13 nm modal pore size with an acidity of 10.336 rnmol KOH/g catalyst. Esterification attained a maximum 93.0% conversion at 70 degrees C freeze-drying temperature, 1.85 weight ratio of ferric sulphate to BHAp and 2.0 wt.% catalyst concentration within 60 min batch time. Application of recyclable solid desiccant during esterification could further significantly augment methyl oleate yield at the derived optimal conditions. The novel catalyst exhibited appreciable reusability and rejuvenation attributes. The present research demonstrates successful application of C. catla bone as a potential support for economical preparation of solid iron acid catalyst, creating an innovative avenue for recycling of this municipal solid waste. (C) 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.