Nanostructured surface
Glucose conversion over nickel-containing zeolites in aqueous medium
Patrylak L.1, Pertko O.1, Povazhnyi V.1, Yakovenko A.1, Konovalov S.1
1 Department of Catalytic Synthesis, V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of  NAS of Ukraine. Murmanska Str., 1, Kyiv-02094, Ukraine. E-mail:lkpg@ukr.net

The negative impact of human activity on the environment contributes to the development of «green» chemistry and using renewable raw materials for production both biofuels and important chemicals. Cellulose is the most abundant non-food biomass, however, the low reactivity of cellulose has prevented its utilize in chemical industry, but the carbohydrates present in it can be depolymerized. The sugars are converted into platform substances such as furfural, hydroxymethylfurfural, lactic acid etc. A range of solid catalysts was used for glucose/fructose conversion, but only a few works deal to zeolite application [1]. Ni-containing zeolites show high activity in the isomerization of n-alkanes [2].  Therefore, the aim of the work was to investigate glucose transformation in water solution over Ni-containing zeolites.
H-forms of zeolite Y, M and ZSM-5 (Si/Al ratio 2.35, 4.5, 20.5 respectively, JS “Sorbent”, Russia) were synthesized and impregnated by nickel nitrate. Catalysts with 5 wt % of nickel were calcined (550 oC, 2 h). Glucose solution (10 wt %) transformation was realized at 160 oC during 4 h. Reaction products were identified by HPLC and GC. For all samples quantitative glucose conversions were gotten. The main products were 5-hydroxymethylfurfural (5-HMF) and humines. 5-HMF molar yield on 5NiHY, 5NiHZSM-5 and 5NiHM was 8.5, 14 and 16 % respectively. DTA investigation of deactivated samples showed twice lower weight of deposits (10 wt %) on 5NiHM and 5NiHZSM-5 than on 5NiHY with the biggest total acidity. HM contains more Lewis acid sites compared to HZSM-5. In addition, 5-HMF yield increases with increasing mesopore radius in H-form of zeolites. The latter is <2, 2.5, 3 nm for HY, HZSM-5 and HM respectively.  
Therefore, Ni-contaning zeolites are active in glucose transformation to 5-HMF in aqua medium. The highest yield of 5-HMF (16 %) was showed by mordenite sample with the biggest radius of mesopores and Lewis acidity.  

1.	Esteban J., Yustos P., Ladero M., Catalytic Processes from Biomass-Derived Hexoses and Pentoses // Catalysts.-2018.- 8.-P. 637-676.
2.	Patrylak L.K., Krylova M.M., Pertko O.P., Voloshyna Yu.G. Linear Hexane Isomerization over Ni-Containing Pentasils //  J. Por. Mater.-2019.-26.-P. 861-868.