Ethanolysis of selected carbohydrates catalyzed by functionalized acidic ionic liquids: An unexpected effect of structural functionalization on selectivity phenomena

A series of functionalized hydrogen sulfate imidazolium ILs were synthesized and applied as catalysts in the reaction of glucose, xylose and fructose with ethanol. In research, the unexpected selectivity phenomena...

Dehydration of Xylose to Furfural over Imidazolium-Based Ionic Liquid with Phase Separation

An environmentally friendly catalyst and task-specific ionic liquid (IL), 1-(4-sulfonic acid) butyl-3-cetyl-2-methyl imidazolium hydrogen sulfate, was applied to the dehydration of xylose to furfural. Its structure was determined by FT-IR, 1H NMR technologies. The solubility of IL in water changed with the temperature, and had the advantages of homogeneous and heterogeneous catalysts. At the given conditions, xylose conversion of 95.3% and furfural yield of 67.5% were achieved over IL.

Production of 5-hydroxymethylfurfural from Japanese cedar (Cryptomeria japonica) in an ionic liquid, 1-methylimidazolium hydrogen sulfate

Production of 5-hydroxymethylfurfural (5-HMF) from Japanese cedar (Cryptomeria japonica) using an ionic liquid, 1-methylimidazolium hydrogen sulfate ([MIM]HSO4), was investigated. 5-HMF can be produced from C. japonica at temperatures above 120 °C. The maximum yield of 5-HMF was about 9 wt% after 15 min of treatment at 160 °C. However, 5-HMF produced in this process tended to decompose as the treatment continued. To avoid decomposition and to provide a means of recovering 5-HMF from [MIM]HSO4, three reaction systems based on [MIM]HSO4 were investigated: biphasic [MIM]HSO4/organic solvent system, [MIM]HSO4 with vacuum distillation, and [MIM]HSO4 with vacuum steam distillation. The [MIM]HSO4 reaction system combined with vacuum steam distillation was most effective. The maximum yield of 5-HMF was 17.5 wt% after treatment for 45 min at 160 °C. The combination of [MIM]HSO4 treatment with vacuum steam distillation is suitable for 5-HMF production because it is a one-pot process without the need for catalysts or pretreatment.

Synthesis and absolute structure of (R)-2-(benzylselanyl)-1-phenylethanaminium hydrogen sulfate monohydrate: crystal structure and Hirshfeld surface analyses

A hydrogen sulfate salt, C15H18NSe+·HSO4 −·H2O or [BnSeCH2CH(Ph)NH3 +](HSO4 −), of a chiral selenated amine (R)-2-(benzylselanyl)-1-phenylethanamine (BnSeCH2CH(Ph)NH2) has been synthesized and characterized by elemental analysis,1H and 13C{1H} NMR, FT–IR analysis, and single-crystal X-ray diffraction studies. The title salt crystallizes in the monohydrate form in the non-centrosymmetric monoclinic P21 space group. The cation is somewhat W shaped with the dihedral angle between the two aromatic rings being 60.9 (4)°. The carbon atom attached to the amine nitrogen atom is chiral and in the R configuration, and, the –C—C– bond of the –CH2—CH– fragment has a staggered conformation. In the crystal structure, two HSO4 − anions and two water molecules form an R 4 4(12) tetrameric type of assembly comprised of alternating HSO4 − anions and water molecules via discrete D(2) O—H...O hydrogen bonds. This tetrameric assembly aggregates along the b-axis direction as an infinite one-dimensional tape. Adjacent tapes are interconnected via discrete D(2) N—H...O hydrogen bonds between the three amino hydrogen atoms of the cation sandwiched between the two tapes and the three HSO4 − anions of the nearest asymmetric units, resulting in a complex two-dimensional sheet along the ab plane. The pendant arrangement of the cations is stabilized by C—H...π interactions between adjacent cations running as chains down the [010] axis. Secondary Se...O [3.1474 (4) Å] interactions are also observed in the crystal structure. A Hirshfeld surface analysis, including d norm, shape-index and fingerprint plots of the cation, anion and solvent molecule, was carried out to confirm the presence of various interactions in the crystal structure.

Spectroscopic and Colorimetric Studies for Anions with a New Urea-Based Molecular Cleft

A new simple urea-based dipodal molecular cleft (L) has been synthesized and studied for its binding affinity for a variety of anions by 1H-NMR, UV-Vis and colorimetric techniques in DMSO-d6 and DMSO, respectively. The results from titration studies suggest that the receptor forms a 1:2 complex with each of the anions used via hydrogen bonding interactions and exhibits strong selectivity for fluoride among halides, showing the binding affinity in the order of fluoride > chloride > bromide > iodide; meanwhile, it displays moderate selectivity for acetate among oxoanions, showing the binding affinity in the order of acetate > dihydrogen phosphate > bicarbonate > hydrogen sulfate > nitrate. Colorimetric studies of L for anions in DMSO reveal that the receptor is capable of detecting fluoride, acetate, bicarbonate and dihydrogen phosphate, displaying a visible color change in the presence of the respective anions.