One step erythritol hydrodeoxygenation towards green butadiene over mixed molybdenum-rhenium supported catalysts

This work explores the one-step catalytic process of erythritol hydrodeoxygenation (HDO) to 1,3-butadiene over supported Re and mixed Mo-Re oxides on carbon black. Catalyst screening under reducing H2 atmosphere was performed in liquid phase under batch conditions. Mixed Mo-Re catalysts show the best HDO performance, as they are active towards C-O scission with mild hydrogenation activity, contributing to preservation of the Cdouble bondC bond of 1,3-butadiene. The effect of reaction parameters was exploited over the promising 5Mo-10Re/CB catalyst. 3-butene-1,2-diol is the main intermediate to 1,3-butadiene formed at short reaction times while longer reaction times lead to butenes. Maximum 1,3-butadiene selectivity 93 % was achieved at 51 % erythritol conversion at 140 °C, 60 bar and 5 h reaction time. XPS measurements of fresh and used materials indicated that the upper surface layer consists of fully and partially reduced Mo and Re species, which according to CH$_3$OH-TPSR host both redox and acid sites.