Selective Lactose Oxidation in Liquid Phase on Au/Al2O3 metallic monolith catalysts.

S.A. REGENHARDT; C.I. MEYER; O. SANZ; S.IVANOVA; M.A. CENTENO; J.A. ODRIOZOLA; M. MONTES; T.F. GARETTO; A.J. MARCHI

San Sebastian

Conferencia; ICOSCAR 5; 2016

Lactose (LA) is a major component of whey, the main by-product in cheese production in dairy industry. Cheese whey typically contains about 5 wt. % lactose, which can be converted to lactobionic acid (LBA) by selective oxidation. This acid has antioxidant properties and its largest commercial use is as an important constituent of solutions to preserve human organs during transplantation procedures. LBA is also employed as acidulant, complexing agent and antioxidant in food and pharmaceuticals industries. Nowadays, LBA is produced by microbiological oxidation of LA. The main disadvantages of this process are the long times required to achieve high levels of conversion and the formation of hydrogen peroxide as a byproduct [1]. Recently, there has been increasing interest in the LBA production by heterogeneous catalytic oxidation of LA. Some authors have studied LA oxidation using different metals and supports [2,3]. It was found that metal, pH, temperature and O2 concentration have important influence on this reaction. Particularly, an active, selective and stable metal for LA oxidation to LBA in aqueous solution is Au, usually supported on SiO2, Al2O3 or carbon powders [2,4]. In this work, we used for the first time an Au/Al2O3 monolithic catalyst to perform this reaction. The aim is to analyze the effect of different process variables, such as stirring rate and temperature of activation and regeneration, on the catalyst activity and stability during the selective conversion of LA to LBA in aqueous phase.