One‐pot conversion of carbohydrates into γ‐valerolactone under the coordination of heteropoly acid based ionic liquid and Ru/ZrO₂ in water media

Abstract

BACKGROUND: The chemical catalytic conversion of carbohydrates into -valerolactone (GVL) is a sustainable alternative to the petrochemical process starting from the depleting fossil resources. Direct conversion of carbohydrates (fructose, glucose, starch and cellulose) into GVL was achieved via the combined heteropoly acid based SO 3 H-functionalized ionic liquid (HAIL) and supported ruthenium (Ru) catalyst system in one pot and in water media. RESULTS: A 63% GVL yield (based on fructose) was obtained under the catalysis of 1-methyl-3-(3-sulfopropylimidazolium) silicotungstate ([MIMPS] 4 SiW) and Ru/ZrO2 at 180 ∘ C, first in 0.1 MPa nitrogen (N 2 ) for 3 h (dehydration), and then in 4 MPa hydrogen (H 2 ) for 10 h (hydrogenation). Under the same reaction conditions, the GVL yields from glucose, starch and cellulose were 68%, 60% and 60%, respectively. The recyclability of the catalytic system consisting of [MIMPS] 4 SiW and Ru/ZrO 2 was investigated in four runs. The activity for [MIMPS] 4 SiW did not change after use. Partial deactivation of Ru/ZrO 2 was observed, which was ascribed to the severe carbon deposition.CONCLUSIONS: In the present method, HAIL and Ru/ZrO 2 catalysts were loaded together. No separation and/or neutralization step reported in the literature was needed and only an atmosphere change (from N 2 to H 2 ) step was involved. Therefore, we provide a promising method for efficient conversion of carbohydrates into GVL.

Silica‐immobilized acid ionic liquid: An efficient catalyst for pentanal self‐condensation

“…Functionalized ionic liquids not only have the advantages of solid inorganic catalysts (easy separation and environmentally friendly), organic-inorganic composite materials (outstanding designability and easy adjustment), and liquid catalysts (good mobility, high density, and uniform distribution of active sites), but they also play the role of solvents, so they are widely used in catalysis, organic synthesis, and other fields. [7][8][9][10] The functionalized ionic liquids have been used to catalyze aldol condensation reactions. For example, acid ionic liquids were used for butanal self-condensation and for aldol condensation of aromatic aldehydes with ketones, [10][11][12][13] basic ionic liquids were employed for aldol condensation of aldehydes with ketones, [14][15][16] and several acid-base bifunctional ionic liquids were synthesized for catalyzing pentanal self-condensation.…”

“…Functionalized ionic liquids not only have the advantages of solid inorganic catalysts (easy separation and environmentally friendly), organic–inorganic composite materials (outstanding designability and easy adjustment), and liquid catalysts (good mobility, high density, and uniform distribution of active sites), but they also play the role of solvents, so they are widely used in catalysis, organic synthesis, and other fields . The functionalized ionic liquids have been used to catalyze aldol condensation reactions.…”