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The hydroxyl radical is often referred to as the "detergent" of the troposphere because it reacts with many pollutants, often acting as the first step to their removal. It also has an important role in eliminating some greenhouse gases like methane and ozone. [3] The rate of reaction with the hydroxyl radical often determines how long many ...
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula −OH and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry , alcohols and carboxylic acids contain one or more hydroxy groups.
Hydroxyl radical (HO·) is generated by Fenton reaction of hydrogen peroxide with ferrous compounds and related reducing agents: Fe(II) + H 2 O 2 → Fe(III)OH + HO· In its fleeting existence, the hydroxyl radical reacts rapidly irreversibly with all organic compounds. superoxide (O − 2) is produced by reduction of O 2. [4]
The hydroxyl radical, Lewis structure shown, contains one unpaired electron. Lewis dot structure of a Hydroxide ion compared to a hydroxyl radical. In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron.
As hydroxyl radicals are short-lived in solution, they need to be generated upon experiment. This can be done using H 2 O 2, ascorbic acid, and Fe(II)-EDTA complex. These reagents form a system that generates hydroxyl radicals through Fenton chemistry. The hydroxyl radicals can then react with the nucleic acid molecules. [17]
The fact that oxygen changes the radiation chemistry might be one reason why oxygenated tissues are more sensitive to irradiation than the deoxygenated tissue at the center of a tumor. The free radicals, such as the hydroxyl radical, chemically modify biomolecules such as DNA, leading to damage such as breaks in the DNA strands. Some substances ...
Finally, the chain is terminated when the hydroxyl radical is scavenged by a ferrous ion: Fe 2+ + HO • + H + → Fe 3+ + H 2 O (step 4: termination) George showed in 1947 that, in water, step 3 cannot compete with the spontaneous disproportionation of superoxide, and proposed an improved mechanism for the disappearance of hydrogen peroxide.
The free radicals generated by this process engage in secondary reactions. For example, the hydroxyl is a powerful, non-selective oxidant. [6] Oxidation of an organic compound by Fenton's reagent is rapid and exothermic and results in the oxidation of contaminants to primarily carbon dioxide and water.