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Acetaldehyde dehydrogenases (EC 1.2.1.10) ... (Antabuse) prevents the oxidation of acetaldehyde to acetic acid and is used in the treatment of alcoholism. ALDH1 is ...
Traditionally, acetaldehyde was mainly used as a precursor to acetic acid. This application has declined because acetic acid is produced more efficiently from methanol by the Monsanto and Cativa processes. Acetaldehyde is an important precursor to pyridine derivatives, pentaerythritol, and crotonaldehyde.
The net result on the substrate is the addition of one oxygen atom. This is seen for example in the oxidation of acetaldehyde to acetic acid by acetaldehyde dehydrogenase, a step in the metabolism of ethanol and in the production of vinegar.
Prior to the commercialization of the Monsanto process, most acetic acid was produced by oxidation of acetaldehyde. This remains the second-most-important manufacturing method, although it is usually not competitive with the carbonylation of methanol.
Acetaldehyde subsequently accumulates and begins to form covalent bonds with cellular macromolecules, forming toxic adducts that, eventually, lead to death of the cell. This same excess of NADH from ethanol oxidation causes the liver to move away from fatty acid oxidation, which produces NADH, towards fatty acid synthesis, which consumes NADH.
and then to acetic acid (ethanoic acid) ALDH2 plays a crucial role in maintaining low blood levels of acetaldehyde during alcohol oxidation. [ 7 ] In this pathway ( ethanol to acetaldehyde to acetate ), the intermediate structures can be toxic, and health problems arise when those intermediates cannot be cleared. [ 3 ]
The oxidation of primary alcohols to carboxylic acids can be carried out using a variety of reagents, but O 2 /air and nitric acid dominate as the oxidants on a commercial scale. Large scale oxidations of this type are used for the conversion of cyclohexanol alone or as a mixture with cyclohexanone to adipic acid .
In both one- and two-stage processes the acetaldehyde yield is about 95% [27] and the production costs are virtually the same. The advantage of using dilute gases in the two-stage method is balanced by higher investment costs. Both methods yield chlorinated hydrocarbons, chlorinated acetaldehydes, and acetic acid as byproducts.