Rekha V.,Catalysis Laboratory |
Sumana C.,Indian Institute of Chemical Technology |
Douglas S.P.,Andhra University |
Lingaiah N.,Catalysis Laboratory
Applied Catalysis A: General | Year: 2014
A series of Co-ZnO catalysts with varying Co to Zn ratio were prepared by co-precipitation method and these were characterized by X-ray diffraction, temperature programmed reduction, H2 chemisorption, X-ray photoelectron spectroscopy and transmission electron microscopy. The developed catalysts were evaluated for selective hydrogenolysis of glycerol to 1,2-propanediol. Glycerol conversion was found to be dependent on the ratio of Co to ZnO and a weight ratio Co/Zn of 50:50 was shown about 70% glycerol conversion with 80% selectivity to 1,2-propanediol. Glycerol hydrogenolysis activity was found to be related to Co metal area as well as amount of ZnO in the catalyst. The proposed catalysts were stable under the reaction conditions and reusable with consistent activity. Different reaction parameters were studied and optimum reaction conditions were established. A kinetic model for the hydrogenolysis reaction was also derived. © 2014 Elsevier B.V. All rights reserved.
Rafi J.M.,Catalysis Laboratory |
Rajashekar A.,Catalysis Laboratory |
Srinivas M.,Catalysis Laboratory |
Rao B.V.S.K.,Indian Institute of Chemical Technology |
And 2 more authors.
RSC Advances | Year: 2015
Karanja seed shells were subjected to pyrolysis in an inert atmosphere at different temperatures to prepare a biochar. The biochar was characterized by X-ray diffraction, FT-infrared spectroscopy, laser Raman spectroscopy, thermogravimetric analysis, CHNS-elemental analysis, BET surface area analysis and for the temperature programmed desorption of ammonia. These biochar carbon catalysts were used as catalysts without any functionalization/treatment for the esterification of glycerol with acetic acid. Carbonization at 400°C led to the formation of biochar with a greater number of strong acidic sites. Amorphous carbon obtained by high temperature carbonization was composed of aromatic carbon sheets oriented in a considerably random fashion. The biochar obtained at 400°C exhibited the highest glycerol esterification activity. The catalytic activity of the biochar was explained based on its properties derived from the different characterization methods. The biochar catalyst can be reused with consistent activity. © The Royal Society of Chemistry 2015.
Srilatha K.,Catalysis Laboratory |
Sree R.,Catalysis Laboratory |
Prabhavathi Devi B.L.A.,Indian Institute of Chemical Technology |
Sai Prasad P.S.,Catalysis Laboratory |
And 2 more authors.
Bioresource Technology | Year: 2012
Biodiesel synthesis from rice bran fatty acids (RBFA) was carried out using cesium exchanged 12-tungstophosphoric acid (TPA) catalysts. The physico-chemical properties of the catalysts were derived from X-ray diffraction (XRD), Fourier transform infrared (FTIR), temperature programmed desorption (TPD) of NH 3 and scanning electron microscopy (SEM). The characterization techniques revealed that the Keggin structure of TPA remained intact as Cs replaced protons. The partial exchange of Cs for protons resulted in an increase in acidity and the catalysts with one Cs + (Cs 1H 2PW 12O 40) showed highest acidity. Under optimized conditions about 92% conversion of RBFA was obtained. The catalyst was reused for five times and retained of its original activity. Pseudo-first order model was applied to correlate the experimental kinetic data. Modified tungstophosphoric acids are efficient solid acid catalysts for the synthesis of biodiesel from the oils containing high FFA. © 2012 Elsevier Ltd.