Pt and Au catalysts, 2 wt% metal loading, supported on SiO2 and Al2O3 were used to study the effect of metal and support on the liquid-phase oxidation of lactose. Pt-based catalysts were prepared by incipient wetness impregnation while Au-based catalysts were obtained by the precipitation-deposition method. Catalytic tests were carried out in aqueous phase at 65 °C, using O2 as oxidizing agent and keeping pH constant at 9 by controlled addition of NaOH aqueous solution. In all of the cases, the only product of reaction detected and quantified was lactobionic acid. It was found that Pt supported on Al2O3 was more active than Pt supported on SiO2. This was explained on the basis that metal Pt dispersion on Al2O3 was three times higher than on SiO2. At the same time, Au/Al2O3 catalyst was more active than Pt/Al2O3 catalysts. The higher activity of Au/Al2O3 was attributed to Au nanoparticles interacting with the support, as determined by transmission electron microscopy. It was also verified that Au/Al2O3 activity was almost the same after two consecutive runs, indicating a good stability of the Au active phase. Kinetic studies were carried out by varying the initial concentration of lactose in the reaction mixture. A negative order respect to the reactant, determined applying a pseudo-homogeneous model, was estimated, which indicates that lactose molecules are strongly adsorbed on the surface of metal Au nanoparticles. A LHHW model, assuming that oxygen chemisorption was the controlling step, allowed to explain the negative order respect to lactose.
Lactose Lactobionic acid Noble metal catalysts Kinetic modeling
This is a preview of subscription content, log in to check access.
We thank the Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT) from Argentina for the financial support of this work. We also acknowledge to LMA-INA-UNIZAR facilities for the transmission electronic microscopy analysis.
Druliolle H, Kokoh KB, Beden B (1997) Electrooxidation of lactose on platinum and on modified platinum electrodes in alkaline medium. Electrochim Acta 39:2577–2584CrossRefGoogle Scholar
Gallezot P (2007) Catalytic routes from renewable to fine chemical. Catal Today 121:76–91CrossRefGoogle Scholar
Budtz P, Vindelev J, Ashie P, Nordkvist M (2005) Enzymatic process for obtained increased yield of lactobionic acid. Canadian Patent WO/2005/104859 A3Google Scholar
Meyer N, Devillers M, Hermans S (2015) Boron nitride supported Pd catalysts for the hydrogenation of lactose. Catal Today 241:200–207CrossRefGoogle Scholar
Gutiérrez LF, Hamoudi S, Belkacemi K (2012) Lactobionic acid: a high value-added lactose derivative for food and pharmaceutical applications. Int Dairy J 26:103–111CrossRefGoogle Scholar
Gangwal VR, van der Schaf J, Kuster BFM, Schouten JC (2005) Influence of pH on noble metal catalysed alcohol oxidation: reaction kinetics and modelling. J Catal 229:389–403CrossRefGoogle Scholar
Tokarev AV, Murzina EV, Mikkola JP, Kuusisto J, Kustov ML, Murzin DYJ (2007) Application of in situ catalyst potential measurements for estimation of reaction performance: lactose oxidation over Au and Pd catalysts. Chem Eng J 134:153–161CrossRefGoogle Scholar
Belkacemi K, Vlad MC, Hamoudi S, Arul J (2007) Value-added processing of lactose: preparation of bioactive lactobionic acid using a novel catalytic method. Int J Chem React Eng 5:A64Google Scholar
Moroz BL, Pyrjaev PA, Zaikovskii VI, Bukhtiyarov VI (2009) Nanodispersed Au/Al2O3 catalysts for low-temperature CO oxidation: results of research activity at the Boreskov Institute of catalysis. Catal Today 144:292–305CrossRefGoogle Scholar
Uriz I, Arzamendi G, Diéguez PM, Laguna OH, Centeno MA, Odriozola JA, Gandía LM (2013) Preferential oxidation of CO over Au/CuOx–CeO2 catalyst in microstructured reactors studied through CFD simulations. Catal Today 216:283–291CrossRefGoogle Scholar
Shimada S, Takei T, Akita T, Takeda S, Haruta M (2010) Influence of the preparation methods for Pt/CeO2 and Au/CeO2 catalysts in CO oxidation. Stud Surf Sci Catal 175:843–847CrossRefGoogle Scholar
Centeno MA, Hadjiivanov K, Tz V, Hr K, Odriozola JA (2006) Comparative study of Au/Al2O3 and Au/CeO2-Al2O3 catalysts. J Mol Catal A 252:142–149CrossRefGoogle Scholar
Tz V, Hr K, Centeno MA, Odriozola JA, Hadjiivanov K (2006) State of gold on an Au/Al2O3 catalyst subjected to different pre-treatments: an FTIR study. Catal Commun 7:308–313CrossRefGoogle Scholar
Regenhardt SA, Trasarti AF, Meyer CI, Garetto TF, Marchi AJ (2013) Selective gas-phase conversion of maleic anhydride to propionic acid on Pt-based catalysts. Catal Commun 35:59–63CrossRefGoogle Scholar
Srinivasan R, Davis BH (1992) X-ray diffraction and electron microscopy studies of platinum-tin-silica catalysts. Appl Catal A 87:45–67CrossRefGoogle Scholar
Bertero NM, Apesteguía CR, Marchi AJ (2008) Catalytic and kinetic study of the liquid-phase hydrogenation of acetophenone over Cu/SiO2 catalyst. Appl Catal A 349:100–109CrossRefGoogle Scholar
Bokwon Y, Hannu H, Uzi L (2003) Interaction of O2 with gold clusters: molecular and dissociative adsorption. J Phys Chem A 107:4066–4071CrossRefGoogle Scholar
Franceschetti A, Pennycook SJ, Pantelides ST (2003) Oxygen chemisorption on Au nanoparticles. Chem Phys Lett 374:471–475CrossRefGoogle Scholar