Synthesis Of Ruthenium Catalysts On Hydrogenation Of Glucose

Supported Ru catalyst was prepared for hydrogenation of glucose tosorbitol. The salt RuCl3was chosen as the precursor to prepare Ru catalyst.The HPLC was used to analyse the samlples taken during the reaction, thenquantitate the glucose concentration of samples according to the standardcurve of glucose. The first order rate constants gotten from changes ofglucose concentration with time combined with conversion of glucose wereadopted to compare the activity of catalysts prepared in different ways. Theinfluences of the types of support, pre-treatment of activated carbon, Rudeposition methods, addition of certain stabilizer, and dechlorination bypost-treatment on catalyst activity were investigated. It was found inexperiment that sodium hypochlorite was much more effective forpretreatment of active carbon than H2O2, however, the influence of chlorideion on the catalyst should be taken into consideration; the glucose conversionwas the highest under the following conditions: the temperature was90oCand the solution pH value was around1during dipping process,which wasreacted for10h, then adjusted the pH as neutral by adding certainconcentration of sodium hydroxide and reduced for12h; Ru/C catalystprepared by adding some sodium citrate as stabilizer showed the bestcatalytic activity and the distribution of Ru particle; washing with differentdetergents after reduction could be more effective to remove chloride ion andpromoted the activity of the catalyst. Finally,5.0wt.%Ru/C catalystprepared under the optimized conditions was reacted at4MPa and120oC,and at last measured a1st-order rate constant as0.485(L/s·kg-cat), which ismuch higher than0.422(L/s·kg-cat) for the commercial5%Ru/C at thesame conditions, what’s more, reduced the hydrogenation reaction timegreatly.