Sulfonic acid functionalized zeolite as efficient bifunctional solid acid catalysts for the synthesis of 5-hydroxymethylfurfural from cellulose

Introduction of the sulfonic acid group into H-beta zeolite to prepare beta-SO3H bifunctional catalysts for the efficient synthesis of 5-hydroxymethylfurfural (HMF) from cellulose. Catalysts characterization, such as XRD, ICP-OES, SEM (Mapping), FTIR, XPS, N-2 adsorption-desorption isotherm, NH3-TPD, Py-FTIR demonstrate the sulfonic acid group was successfully grafted onto the beta zeolite. A superior HMF yield (59.4 %) and cellulose conversion (89.4 %) was obtained in the H2O(NaCl)/THF biphasic system under 200 degrees C for 3 h with beta-SO3H(3) zeolite as catalyst. More valuable, beta-SO3H(3) zeolite converts other sugars and obtains ideal HMF yield, including fructose (95.5 %), glucose (86.5 %), sucrose (76.8 %), maltose (71.5 %), cellobiose (67.0 %), starch (68.1 %), glucan (64.4 %) and also converts plant material (25.1 % for moso bamboo and 18.7 % for wheat straw) with great HMF yield. beta-SO3H(3) zeolite catalyst keeps an appreciable recyclability after 5 cycles. Moreover, in the presence of beta-SO3H(3) zeolite catalyst, the by-products during the production of HMF from cellulose were detected, and the possible conversion pathway of cellulose to HMF was proposed. The beta-SO3H bifunctional catalyst has excellent potential for the biorefinery of high value platform compound from carbohydrates.