The conversion of fructose, glucose, and sucrose to 5-(hydroxymethyl)furfural (HMF) and levulinic acid (LA)/formic acid (FA) was investigated in detail using sulfuric acid as the catalyst and γ-valerolactone (GVL) as a green solvent. The H 2 SO 4 /GVL/H 2 O system can be tuned to produce either HMF or LA/FA by changing the acid concentration and thus allowing selective switching between the products. Although the best yields of HMF were around 75%, the LA/FA yields ranged from 50% to 70%, depending on the structure of the carbohydrates and the reaction parameters, including temperature, acid, and carbohydrate concentrations. While the conversion of fructose is much faster than glucose, sucrose behaves like a 1:1 mixture of fructose and glucose, indicating facile hydrolysis of the glycosidic bond in sucrose. The mechanism of the conversion of glucose to HMF or LA/FA in GVL involves three intermediates: 1,6-anhydro-β-D-glucofuranose, 1,6-anhydro-β-D-glucopyranose, and levoglucosenone.
Nonafluoro-t-butyl propyl (1), allyl (2), and propargyl (3) ethers as well as 1,2-bis(nonafluoro-t-butoxy)ethane (4), 1,3-bis(nonafluoro-t-butoxy)-propane (5), and 1,4-bis(nonafluoro-t-butoxy)-butane (6) were prepared by the reaction of sodium nonafluoro-t-butoxide (7) with the corresponding alkyl halides in good yields. Their fluorous partition coefficients and toxicity were also investigated. Computational studies have shown that 4, 5 and 6 exist in a monomeric form in MeOH-CF 3 C 6 F 11 and they likely aggregate to form oligomers in PhCH 3 -CF 3 C 6 F 11 . † Electronic supplementary information (ESI) available. See
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