Effect of glucose on lowering Al–Ni alloy consumption in dehalogenation of halogenoanilines

Hydrodechlorination of Different Chloroaromatic Compounds at Room Temperature and Ambient Pressure—Differences in Reactivity of Cu- and Ni-Based Al Alloys in an Alkaline Aqueous Solution

“…Al-Ni is the most expensive reagent, however, in this HDC system which disfavored the application of this technique even in the case of three-times repeated Al-Ni recycling. We observed that using NaOH or KOH and Al-Ni alloy for HDC of Ar-Cl in molar ratio 10:2:1, the HDC is completed within 120 min in the case of monochloroanilines and the quantity of used Raney Al-Ni alloy could even be lowered by addition of glucose in some cases [23].…”

“…In addition, attempts to recycle an already used Devarda's Al-Cu-Zn alloy for subsequent HDC of 3-or 2-chloroaniline completely failed. Weidlich et al [23] published a method available for reducing the minimal quantity of Al-Ni alloy for HDC of several Cl-ANs. This method is based on the addition of glucose which works as an oxidation inhibitor of Raney Al-Ni in the diluted NaOH solution.…”

“…Apart from bimetals, several Al-based metallic alloys containing Cu or Ni (Al-Cu and Al-Ni) have been published as very effective for HDC of Ar-Cls [18][19][20][21][22][23][24][25][26] due to the high quantity of Ni (or Cu, respectively) working as HDC catalysts compared with bimetals where electropositive metal (source of reductant) is covered with a thin layer of HDC catalyst. Raney Al-Ni alloy (which contains 50 wt.% of Al and 50 wt.% of Ni) in a diluted aqueous base seems to be an especially effective HDC reagent exploiting both the reduction potential of Al in the alkaline aqueous solution with the high HDC activity of in situ produced Raney Ni [18][19][20][21][22][23][24][27][28][29]. The role of the base in the HDC reaction mediated by the Al-Ni alloy was studied in several works [21,24,28,29].…”

“…In this study, the long reaction time (around 16 h) was used usually in describing HDC experiments to achieve completion of the HDC reaction (at least more than 10 half-lives of HDC reaction) [21,26]. A concentration of diluted aqueous NaOH solution and an excess of both tested Al alloys were chosen on the basis of our earlier published results by studying the hydrodehalogenation of halogenated anilines and phenols [21][22][23][24]26]. Changes in the structures of both mentioned alloys are presented during a HDC reaction in the diluted aqueous NaOH solution.…”

Intramolecular homolytic substitution in selenoxides and selenones

“…163 Monosaccharides can also be added to organic transformations 164 to act as reductants for chemical process that occur in the 165 absence of catalyst 60,61 or to reduce a metal precatalyst to the 166 necessary oxidation state in situ so that the reaction can proceed. This concept has been employed for a variety of 168 reactions such as dehalogenations, 62 69 Additionally, a four component 182 process resulted in the efficient formation of 3-phenyl-2-[4-{(1-phenyl-1H-1,2,3-triazol-4-yl)methoxy}phenyl]thiazolidin-4ones 29 from readily available starting materials (Scheme 8b). 70 In both cases, the glucose is purported to reduce the copper to In contrast to other related reports (vide inf ra), exogenous capping agents were used in this study.…”