Enhanced Catalytic Activity of Modified ZSM-5 Towards Glucose Isomerization to Fructose

The present study focuses on generating mesopores within H-ZSM-5 (H-Z) zeolite via desilication and dealumination to incorporate Lewis acidic metal, such as Sn, into the framework (Sn(4)ZS(180)A(15)) to catalyse glucose isomerisation. Sn(4)ZS(180)A(15) possesses enhanced surface area (457 m(2) g(-1)), mesopore volume (0.585 cm(3) g(-1)) and a high weak-medium to strong acidic sites ratio, compared to parent H-Z (395 m(2) g(-1); 0.174 cm(3) g(-1)). DRS-UV-Vis and XPS results corroborate Sn incorporation into the framework of Sn(4)ZS(180)A(15), based on the absorbance peak around 200-220 nm and peaks appearing at 495.8 and 487.4 eV, respectively. Sn(4)ZS(180)A(15) exhibits higher catalytic activity towards glucose isomerisation in ethanol-water at 110 degrees C, yielding 44.2 % fructose with 80.0 % selectivity. Conversely, the parent H-Z afforded negligible glucose conversion with a fructose yield of <1 % under identical conditions. Moreover, Sn-incorporated on dealuminated (Sn(4)ZS(0)A(15)) and desilicated (Sn(4)ZS(180)A(0)) catalysts give a low yield of fructose (7-10 %), signifying the requirement of the desilication-dealumination process before incorporating Sn into the framework.

Automated summary

The study focuses on incorporating Lewis acidic metal Sn into H-ZSM-5 zeolite through desilication and dealumination to generate mesopores, and investigates its catalytic activity for glucose isomerisation. The Sn(4)ZS(180)A(15) catalyst shows enhanced surface area, mesopore volume, and acidic sites compared to the parent H-Z. DRS-UV-Vis and XPS results confirm the incorporation of Sn into the framework of Sn(4)ZS(180)A(15). The Sn(4)ZS(180)A(15) catalyst exhibits high catalytic activity for glucose isomerisation, while the parent H-Z and Sn-incorporated catalysts without desilication-dealumination process show low activity.