40460-44-4Relevant articles and documents
Solvolysis of (4-Nitrophenoxy)ethylene Oxides
Shipley, David S.,Ross, Angela M.,Mohan, Ram S.,Whalen, Dale L.,Sayer, Jane M.,et al.
, p. 977 - 983 (1994)
(4-Nitrophenoxy)ethylene oxide (1a) (2-chloro-4-nitrophenoxy)ethylene oxide (1b), and (4-phenylphenoxy)ethylene oxide (1c) were synthesized.Rates of acid-catalyzed, noncatalyzed, and hydroxide ion-catalyzed reactions for 1a and 1b and rates of acid-catalyzed and noncatalyzed hydrolysis of 1c were measured in 0.1 M NaClO4 solutions.Acid-catalyzed hydrolysis of 1a is ca. 6200 times faster than that of 4-nitrostyrene oxide, and that of 1c is 57 times faster than that of styrene oxide.These increased rates are attributed to stabilization of developing positive charge on the acetal carbon by the phenoxy oxygen that is present in the substituted phenoxyethylene oxides but not in the styrene oxides.The pH-rate profiles for reaction of 1a and 1b in 1.0 M KCl solutions over the pH range 2-14 were determined.At intermediate pH, the rates of reaction of 1a and 1b in 1.0 M KCl solutions are ca. 6-8 times faster than the corresponding rates in 0.1 M NaClO4 solutions.From rate and product studies, these increased reaction rates in KCl solutions were attributed to bimolecular attact of chloride ion at the methylene carbon of the epoxy moiety.The reactivity of 1a is greater than that of 1b toward acid-catalyzed hydrolysis but less than that of 1b in both noncatalyzed and hydroxide ion-catalyzed hydrolysis.Compound 1c reacts about 73-fold faster than 1a in acid and about 11-fold faster in the noncatalyzed reaction.From reactivity considerations, it is proposed that H2O and HO(1-) also add as nucleophiles to the methylene carbon of the epoxide moieties of 1a and 1b, whereas H2O adds to the acetal carbon of 1c.
Investigation of the mechanism of dissociation of glycolaldehyde dimer (2,5-dihydroxy-1,4-dioxane) by FTIR spectroscopy
Yaylayan, Varoujan A.,Harty-Majors, Susan,Ismail, Ashraf A.
, p. 31 - 38 (2007/10/03)
Glycolaldehyde represents the simplest α-hydroxycarbonyl moiety - a common structural feature of reducing sugars. It exists in solid state, only in crystalline dimeric form as 2,5-dihydroxy-1,4-dioxane. However, in solution phase or during heating, it dissociates into different dimeric and monomeric forms. FTIR spectroscopy was used to study the effect of temperature, pH and solvent on the dissociation and chemical transformations of glycolaldehyde. The infrared spectra were recorded in different solvents as a function of time and temperature (both during heating and cooling cycles) between 30 and 85°C. During heating, glycolaldehyde cyclic dimer generated two bands in the carbonyl region, one at 1744 cm-1 and the other at 1728 cm-1. These bands increased during the heating cycle and decreased during the cooling cycle. The data indicated that the glycolaldehyde cyclic dimer (2,5-dihydroxy-1,4-dioxane) undergoes a ring opening to form the acyclic dimer (1728 cm-1) that can recyclize into the 2-hydroxymethyl-4-hydroxy-1,3-dioxolane structure. The acyclic dimer can also dissociate into monomeric glycoladehyde (1744 cm-1) in equilibrium with the enediol form (1703 cm-1). There is evidence to indicate oxidation of glycolaldehyde into glycolic acid during heating, in either neutral or basic aqueous solutions.
