Latin American Applied Research 53(1):13-18 (2023) TRABAJOS SELECCIONADOS DEL XII CONGRESO ARGENTINO DE CATÁLISIS https://doi.org/10.52292/j.laar.2023.1143 13 ANALYSIS OF CATALYTIC BEHAVIOR OF RHENIUM PROMOTED PT/TIO2 CATALYST IN ERYTHRITOL HYDROGENOLYSIS E.M. VIRGILIO † , M.E. SAD and C.L. PADRÓ Catalysis Science and Engineering Research Group (GICIC) Instituto de Investigaciones en Catálisis y Petroquímica -INCAPE-(UNL-CONICET) CCT Santa Fe, Colectora RN 168 km 0, Paraje El Pozo, (3000) Santa Fe, Argentina. † evirgilio@fiq.unl.edu.ar Abstract−− Rhenium modified Pt/TiO2 catalyst has been tested during erythritol (ERY) hydrogenolysis reaction in a slurry reactor. N2 physisorption, temper- ature programmed reduction and CO chemisorption characterizations were performed. After reduction treatment, Pt species were fully reduced with a dis- persion of 26% whereas Re species remained partially oxidized. ERY may convert through four pathways: isomerization, dehydration and C-O or C-C hydro- genolysis. Pt-Re/TiO2 was active and selective to bu- tanetriols and butanediols formation. The influence of temperature (423–498 K) and reactant concentrations (15-35 barH2 and 0.2-0.6 MERY) on catalytic activity and products distribution were evaluated; the activa- tion energy and the reaction orders for each route were estimated. Dehydration pathway displayed the highest activation energy whereas isomerization showed the lowest value. The order to ERY and H2 were 0.23 and 0.97 respectively, for C-O hydrogenol- ysis route and is consistent with two different mecha- nisms proposed for the removal of primary or second- ary OH group. Keywords−− bimetallic catalysts – C-O hydrogen- olysis – Kinetic study – C4 polyols. I. INTRODUCTION The study of lignocellulosic biomass and derivatives as raw materials for the production of valuable compounds has gained great interest in the last decades. Among this biomass derived molecules can be found a C4 polyol: erythritol (ERY, C4H10O4), that is a stable sugar alcohol widely present in fruits, fermented foods, and animals. Erythritol has a O/C=1 ratio, and therefore the excess of oxygen must be removed to produce fuels and valuable chemicals. One of the most interesting methods to re- move oxygen atoms is deoxygenation (Nakagawa et al., 2020), involving the dissociation of C−O bonds, and re- placing it by C−H bonds. For this reaction, the use of some reducing agents like molecular hydrogen (H2) is re- quired. Deoxygenation of alcohols using molecular hy- drogen is called hydrodeoxygenation or C−O hydrogen- olysis and typically, supported noble metals (Pt, Ru, Rh, and Ir) are capable of catalyze these reactions. A large number of works have been published using Rh or Ir cat- alysts together with a promoter oxide (Re or Mo) for C- O hydrogenolysis of polyols such as glycerol (GLY) or ERY. The effect of the support, the addition of acid co- catalysts, the metal content and the reaction conditions strongly affect the product distribution since several competitive routes usually get involved when an aqueous polyol solution and H2 reacts in presences of metal cata- lysts (Amada et al., 2012; Said et al., 2017; Tomishige et al., 2014; Virgilio et al., 2021). In a previous work (Virgilio et al., 2021), TiO2 was selected as the most con- venient support for Ir-based catalysts, to favor C-O scis- sions of ERY to render butanediols (BDO). Pt catalysts were less studied for polyols hydrogenol- ysis. Actually, Pt-Re/SiO2 (4%wt. Pt, Re/Pt=0.25) re- sulted less active than Ir-Re/SiO2 during GLY hydrogen- olysis at 373 K although the products distribution were similar forming mainly 1,3-propanediol (13PDO) (Amada et al., 2011). Some discrepancy was found when comparing the catalytic activity of Pt-W catalysts during GLY hydrogenolysis. Liu et al. (2019) informed that W- modified Pt (5-38 %wt. of W and 1-9 %wt. of Pt) cata- lysts supported on different solids displayed very low conversion (less than 5%) at 403-493 K and 10-80 barH2 resulting unattractive when comparing with Ir catalysts. On the other hand, it was also reported a 13PDO selec- tivity of 46% for GLY conversion of 70% on Pt- WOx/ZrO2 (3 %wt. Pt and 10 %wt. W) at 403 K and 40 barH2 (Gong et al., 2010). Finally, Daniel et al. have re- ported that Pt-Re (5.5%wt of each metal) supported on carbon have been selective in the conversion of GLY to PDO at 443 K and 40 barH2, while monometallic Pt/C only favored the breaking of C-C bonds (Daniel et al., 2010). Regarding ERY hydrogenolysis, it has been reported that Pt-WOx/SiO2 can produce 1,4-butanediol (14BDO) from ERY at 413 K and 80 barH2 (40% selectivity and 83% conversion) at 24 h (Liu et al., 2020) but the time evolution of products were not informed. Moreover, rhe- nium promoted Pt has not been tested in this reaction ac- cording to our best knowledge. Herein, we present the catalytic performance of Pt- Re/TiO2 in ERY conversion under different reaction tem- peratures and reactant concentrations. Furthermore, we estimate kinetic parameter as activation energy and reac- tion orders of routes involved in the ERY transformation. II. EXPERIMENTAL SECTION A. Catalyst preparation and characterization Pt-Re/TiO2 catalyst was prepared by sequential incipient wetness impregnation with Ir and Re aqueous solution. Prior impregnation, the support (TiO2, Degussa P-25) was treated in air flow at 723 K for 4 h. Then, the support