29456-04-0Relevant articles and documents
Vinyl Alcohol: Generation and Decay Kinetics in Aqueous Solution and Determination of the Tautomerization Equilibrium Constant and Acid Dissociation Constants of the Aldehyde and Enol Forms
Chiang, Y.,Hojatti, M.,Keeffe, J. R.,Kresge, A. J.,Schepp, N. P.,Wirz, J.
, p. 4000 - 4009 (1987)
Vinyl alcohol was generated in aqueous solution by Norrish type II photoelimination of 5-hydroxy-2-pentanone and by the acid-catalyzed hydrolysis of a ketene acetal (1-(vinyloxy)-1-methoxyethene) and an ortho ester (2-(vinyloxy)-2-phenyl-1,3-dioxolane), and rates of isomerization of this enol to acetaldehyde catalyzed by hydronium and hydroxide ions and formic and acetic acid buffers were measured.Rates of enolization of acetaldehyde, determined by iodine scavenging and catalyzed by hydronium and hydroxide ions, were also measured.These data lead to two concordant, independent determinations of the tautomerization equilibrium constant for acetaldehyde in aqueous solution whose average is KE=(5.89+/-0.81)x10-7, pKE=6.23+/-0.06.They also give KaE=(3.13+/-0.17)x10-11, pKaE=10.50+/-0.02, for the dissociation constant of vinyl alcohol ionizing as an oxygen acid, and KaK=(1.85+/-0.27)x10-17, pKaK=16.73+/-0.06, for the dissociation constant of acetaldehyde ionizing as a carbon acid; all equilibrium constants are concentration quotients and refer to aqueous solution at ionic strength 0.10 M.Kinetic solvent isotope effects on both enolization and ketonization suggest that reaction occurs by a stepwise rather than a concerted mechanism.
Comparative studies of the photocatalytic and microwave -assisted degradation of alizarin red using ZnO/poly(1- naphthylamine) nanohybrids
Riaz, Ufana,Ashraf,Budhiraja, Vaibhav,Aleem, Sadaf,Kashyap, Jyoti
, p. 259 - 267 (2016/01/20)
Semiconductors such as ZnO and TiO2 have been extensively utilized in the photocatalytic degradation of dyes. However till date, no study has been reported to compare the catalytic efficiency of such organic-inorganic hybrids under UV light and microwave irradiation separately. The present work reports the synthesis of poly(1-naphthylamine)/ZnO nanohybrids. The structure and morphology of the synthesized nanocomposites were characterized using FT-IR, UV, XRD, TEM and Cyclic voltammetry analyses. The dye degradation studies were done separately in a photochemical reactor and in laboratory microwave oven and the fragments were identified using LC-MS technique. Results showed that under microwave irradiation, the efficiency of ZnO/PNA as catalyst was higher as compared to UV irradiation. Higher extent of ?OH radical generation was confirmed in microwave as compared to UV irradiation which was found to be responsible for the high rate of degradation of dye solution. A plausible degradation pathway was proposed.
PROCESS FOR PRODUCTION OF ACROLEIN AND OTHER OXYGENATED COMPOUNDS FROM GLYCEROL IN A TRANSPORTED BED REACTOR
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Page/Page column 9-12, (2008/12/05)
Disclosed is a process for the production of acrolein and other oxygenated compounds from glycerol. Use is made of an acidic catalyst in a moving bed reactor at 200 - 650°C.
