Catalytic reduction in subcritical water

Acid-Catalyzed Production of 5-Hydroxymethyl Furfural from d-Fructose in Subcritical Water

“…Because of these properties, along with the higher concentration of hydrogen and hydroxide ions, 7 it seems to be a good alternative medium. 37 A few studies on the production of HMF in the sub-CW have been reported: in the presence of H 2 SO 4 as a catalyst, 11 at 523 K, the combined yield of 60% was obtained for HMF and furfural. Antal et al 12 have studied the mechanism of dehydration of fructose at sub-CW at 523 K, and they have reported yields of 47% and 53% for HMF in the absence and presence of H 2 SO 4 as the catalyst, respectively.…”

Synthesis of quinolines, pyridine ligands and biological probes in green mediaThis work was presented at the Green Solvents for Catalysis Meeting, held in Bruchsal, Germany, 13–16th October 2002.

“…Ethyl formate in hot pressurized water has been shown to be an effective green reducing system for olefins, acetylenes and aldehydes. 10 However the nitro group can be selectively reduced in the presence of aldehydes and ketones in a pressure reactor at 170-200 °C yielding the Friedländer quinoline product in good to modest yields (Table 1, method A). 11,12 The yields of this combined one-step quinoline preparation is generally close to the overall yield of a two-step procedure from o-nitrobenzaldehyde.…”

On-line monitoring of the hydrolysis of acetonitrile in near-critical water using Raman spectroscopy

“…Recently, we have reported how scH 2 O can be used as an effective solvent for the selective partial oxidation of paraxylene to terephthalic acid [24], a key reaction in the manufacture of bulk chemicals for the polyester industries [25]. Most synthetic chemistry, however, is performed in the near-critical region (also known as sub-critical) [26][27][28][29][30][31]. The latter is an arbitrarily defined region of the liquid phase, where organic compounds are stable, because of the lower temperatures employed, the dielectric constant is comparable to that of organic solvents, and the ionic product is sufficiently increased to favour acid/base catalysed reactions.…”