Periodic DFT Study of the Opening of Fructose and Glucose Rings and the Further Conversion of Fructose to Trioses Catalyzed by M‑BEA (M = Sn, Ti, Zr, or Hf)

Periodic density
functional theory calculations with long-range
corrections were used to analyze the opening of fructose and glucose
rings catalyzed by metal-substituted β zeolites (M-BEA). The
reaction mechanisms were systematically analyzed on BEA substituted
with tin (Sn), titanium (Ti), zirconium (Zr), and hafnium (Hf). Here,
we proposed a mechanism for the conversion of fructose to dihydroxyacetone
and glyceraldehyde and a novel mechanism for the glucose ring opening.
The preferential site of substitution of the metals in BEA was reported.
The adsorption energies of fructose and glucose through their different
oxygen atoms on M-BEA were also reported. The transition state energies
were calculated using the nudged elastic band and dimmer methods.
Among the zeolites studied, Sn-BEA displays the lowest energies barriers
for the conversion of the fructose to its trioses and for the glucose
ring opening.