Acetaldehyde hydroxyl radical reaction

A series of six a-pinene hydroxyl radical reaction products were derivatized with 2,4-dintirophenylhydrazine (DNPH) (formaldehyde, acetaldehyde, acetone, pinonal-dehyde [both mono- and di-DNPH substituted], campholenealdehyde) and separated on 35°C C 8 column (A = 360nm) using a 95/5 -> 16/84 (at 50min hold lOmin) gradient [1229], Peak shapes and resolution were excellent. Peak identities were confirmed by negative ion APCI. 

In 1977, Kellogg and Fridovich [28] showed that superoxide produced by the XO-acetaldehyde system initiated the oxidation of liposomes and hemolysis of erythrocytes. Lipid peroxidation was inhibited by SOD and catalase but not the hydroxyl radical scavenger mannitol. Gutteridge et al. [29] showed that the superoxide-generating system (aldehyde-XO) oxidized lipid micelles and decomposed deoxyribose. Superoxide and iron ions are apparently involved in the NADPH-dependent lipid peroxidation in human placental mitochondria [30], Ohyashiki and Nunomura [31] have found that the ferric ion-dependent lipid peroxidation of phospholipid liposomes was enhanced under acidic conditions (from pH 7.4 to 5.5). This reaction was inhibited by SOD, catalase, and hydroxyl radical scavengers. Ohyashiki and Nunomura suggested that superoxide, hydrogen peroxide, and hydroxyl radicals participate in the initiation of liposome oxidation. It has also been shown [32] that SOD inhibited the chain oxidation of methyl linoleate (but not methyl oleate) in phosphate buffer. 

Morris, E.D., Jr., Stedman, D.H., and Niki, H. Mass spectrometric study of the reactions of the hydroxyl radical with ethylene, propylene, and acetaldehyde in a discharge-flow system, J. Am. Chem. Soc., 93(15) 3570-3572, 1971. 

Other than water, protein is the major constituent of meat averaging nearly 21% in heef or chicken meat, with fat varying fiom 4.6 to 11.0% in beef and fiom 2.7 to 12.6% in chickoi. The principal radiolytic reactions of aqueous solutions of aliphatic amino acids are reductive deamination and decarboxylation. Alanine yields NH3, pyruvic add, acetaldehyde, propionic acid, CO2, H2, and ethylamine (6). Sulfur-containing amino adds are espedally sensitive to ionizing radiation. Cysteine can be oxidized to cystine by the hydroxyl radical or it can react with the hydrated electron and produce... 

Taylor et al. [104] investigated the reaction of hydroxyl radicals with acetaldehyde in a wide temperature range using a quantum RRK model to describe the competition between addition and abstraction. They conclude that different reaction mechanisms occur, depending on the temperature, and that OH addition followed by CH3 elimination is the dominant reaction pathway between 295 and 600 K. Moreover, they claimed that the H-atom elimination pathway is largely insignificant, except possibly at the lowest temperatures. 

Rayez MT, Rayez JC, Berces T, Lendvay G. (1993) Theoretical study of the reactions of hydroxyl radicals with substituted acetaldehydes. J Phys Chem A 97 5570-5576. 

Reactions of formaldehyde and acetaldehyde with hydroxyl radicals... 

Because of its high reactivity, SCW can act as both an oxidant and catalyst. As was shown experimentally, even in the gas phase at low temperatures, water, due to its ability to form hydrogen bonds, can act as a molecular catalyst, capable of increasing the rate of the reaction of hydroxyl radicals with acetaldehyde [223]. Such effects are even more expected in SCW. 

Give a sequence of reactions leading to the formation of acetaldehyde from ethane starting with the reaction of hydroxyl radical. 

Michael, J.V., D.G. Keil, and R.B. Klemm (1985), Rate constants for the reaction of hydroxyl radicals with acetaldehyde from 244-528 K, J. Chem. Phys., 83, 1630-1636. 

Vandenberk, S., and J. Peelers (2003), The reaction of acetaldehyde and propionaldehyde with hydroxyl radicals Experimental determination of the primary H2O yield at room temperature, J. Photochem. Photobiol. A, 157, 269-21 A. 

In studying the reaction of oxygen atoms with CH3CHO by using the photochemical method, at a pressure of 100 mm. Hg and with sensitization by mercury, Cvetanovi664 came to another conclusion, namely, that the reaction of oxygen atoms with acetaldehyde yielded mainly hydroxyl and the CH3CO radical. The hydroxyl formed reacted with an acetaldehyde molecule to form water, and acetyl yields diacetyl. The main reaction products were found to be water and biacetyl. 

---