(764b) Multifunctional Homogeneous-Heterogeneous Polymer Catalysts for the Synthesis of Hydroxymethylfurfural from Glucose

Homogenous catalysts are generally more active than their heterogeneous counterparts because the solubility in the reaction medium contributes to access of reactants to all active sites. However, heterogeneous catalysts are commonly preferred since catalysts can be easily recovered from the medium and be reused. Poly(styrenesulfonic acid) (PSSA) combines the advantages of both homogeneous and heterogeneous catalysis. PSSA is soluble in polar solvents; therefore, all acidic sulfonic groups are readily accessible. In addition, the catalyst cannot be deactivated through coking because there is no surface for the carbonaceous species to be deposited. At the same time, PSSA, due to its high molecular weight, can be easily recovered by ultrafiltration for further utilization.

PSSA can be obtained by sulfonation of polystyrene waste (e.g., yogurt packaging or expanded polystyrene), which is an additional advantage from an environmental point of view [1]. This polymer catalyst demonstrated high activity in several biomass conversion reactions that require Brønsted acid sites: synthesis of biodiesel from vegetable oil [1], dehydration of xylose to furfural, and furfural oxidation to maleic and succinic acids [2]. Here we present the addition of Lewis acid functionality to this polymer for a one-pot synthesis of hydroxymethylfurfural (HMF) from glucose.

1. Alonso-Fagúndez, N.; Laserna, V.; Alba-Rubio, A.; Mengibar, M.; Heras, A.; Mariscal, R.; Granados, M. L., Poly-(styrene sulphonic acid): An acid catalyst from polystyrene waste for reactions of interest in biomass valorization. Catalysis Today 2014, 234, 285-294.

2. Granados, M. L.; Alba-Rubio, A. C.; Sádaba, I.; Mariscal, R.; Mateos-Aparicio, I.; Heras, Á., Poly(styrenesulphonic) acid: an active and reusable acid catalyst soluble in polar solvents. Green chemistry 2011, 13(11), 3203-3212.