631-59-4Relevant articles and documents
Raman spectroscopy of glyoxal oligomers in aqueous solutions
Avzianova, Elena,Brooks, Sarah D.
, p. 40 - 48 (2013)
Raman microscopy and Attenuated Total Reflection infrared spectroscopy were utilized to facilitate investigations of equilibria between various hydrated and oligomeric forms of glyoxal in aqueous glyoxal solution droplets. The assignment of spectra is obtained with the assistance of B3LYP density functional quantum chemical calculations of vibrational wavenumbers, Raman activities, and infrared intensities. Several forms of glyoxal derivatives with similar functional groups, e.g., hydroxyl and dioxolane rings, are found to be present. The absence of a Raman spectral peak corresponding to the vibrational carbonyl stretch provides evidence that both carbonyl groups of a glyoxal molecule become hydrated in solutions of a broad concentration range. The presence of bands corresponding to deformation vibrations of the dioxolane ring indicates that dihydrated glyoxal oligomers are formed in glyoxal solutions with concentrations of 1 M and higher. Under typical ambient temperature and humidity conditions, concentrated glyoxal solution droplets undergo evaporation with incomplete water loss. Our results suggest that formation of crystalline glyoxal trimer dihydrate from concentrated solutions droplets is hindered by the high viscosity of the amorphous trimer and requires dry conditions that could rarely be achieved in the atmosphere. However, crystallization may be possible for droplets of low initial glyoxal concentrations, such as those produced by evaporating cloud droplets.
Kinetics, Mechanism, and Thermodynamics of Glyoxal-S(IV) Adduct Formation
Olson Terese M.,Hoffmann, Michael R.
, p. 533 - 540 (2007/10/02)
The reversible addition of glyoxal (ethanedial) and S(IV) to form glyoxal monobisulfite (GMBS) was studied spectrophotometrically over the pH range of 0.7-3.3.Far from equilibrium, the rate of GMBS formation is given by d/dt = (k1,appα1) + k2,appα2), where = + + , = + -> + 2->, α1 = ->/, and α2 = 2->/.The apparent rate constants, k1,app = 0.13 M-1 s-1 and k2,app = 2.08E3 M-1 s-1, are pH independent functions of the dehydration equilibrium constants of (CH(OH)2)2 and CHOCH(OH)2, and intrinsic rate constants for the reaction of HSO3- and SO32- with unhydrated and singly hydrated glyoxal.Glyoxal dibisulfite (GDBS) and GMBS were shown to dissociate with a rate given by d/dt = -1 + k"-1KD3 + (k'-2K'a2 + k"-2K"a2KD3)/+>>t + -3 + k-4Ka3/+>>t, where k-1 and k-2 correspond to the release of bisulfite and sulfite, respectively, from unhydrated and hydrated GMBS species; k-3 and k-4 correspond to the release of bisulfite and sulfite from GDBS; KD3 is the dehydration constant for GMBS; K'a2, K"a2, and Ka3 are acid dissociation constants.Stability constants for the formation of GMBS and GDBS were determined to be cK1 = ->/(-) = 2.81E4 M-1 and cK2 = -)2>/(->->) = 1.45E4 M-1 at 25 deg C and μ = 0.2 M.
