Acetaldehyde, reaction with wood

The liver enzymes that oxidize ethanol to acetaldehyde are the same as those that oxidize methanol to formaldehyde. Physicians take advantage of this in the treatment of wood alcohol poisoning by trying to keep those enzymes busy with a reaction that produces a less toxic (not nontoxic) by-product. In cases of methanol poisoning, the patient receives ethanol intravenously. The ethanol should then be in greater concentration than methanol and should compete successfully for the liver enzymes and be converted to acetaldehyde. This gives the body time to excrete the methanol before it is oxidized to the potentially deadly formaldehyde. 

Carbonyl compounds are probably present at low levels in all air samples (Fung and Grosjean, 1981). A great variety of combustion processes produce aldehydes they are particularly abundant in wood smoke, and have also been identified in the products of combustion of natural gas and fuel oil, and in engine exhaust samples. It is likely that they are relatively long-lived intermediates in atmospheric photooxidation reactions. Formaldehyde (CH2O), for example, is always an obligatory intermediate in the conversion of methane to CO2. In nearly all air samples so far examined, formaldehyde has been the most abundant aldehyde, with acetaldehyde, pro-pionaldehyde, acrolein, benzaldehyde, crotonaldehyde, and furfural sometimes present at much lower concentrations (Kuwata et al., 1979 Penkett, 1982 Zhou and... 

There were also improvements in acetaldehyde and acetic anhydride manufacture. Ag based catalysts for the partial oxidation of ethanol became available around 1940. When used to oxidatively dehydrogenate ethanol [14], the conversion of ethanol to acetaldehyde was no longer equilibrium limited since the reaction was now very exothermic. Fortunately, the process still displayed excellent selectivity (ca. 93-97%) for acetaldehyde. This technology replaced the older Cu-Cr processes over the period of the 1940-1950 and made ethanol a much more attractive resource for acetaldehyde. When ethylene became available as a feedstock in the 1940 s through 1950 s, ethanol became cheaply available via ethylene hydration (as opposed to traditional fermentation). With ethanol now cheaply available from ethylene, the advent of the Ag catalyzed oxidative dehydration to acetaldehyde rapidly accelerated the shutdown of the last remaining wood distillation units. 

Most acetate esters, however, are produced from acetaldehyde using the Tishchenko reaction. In addition, ether acetates are used as solvents for nitrocellulose, acrylic lacquers, varnish removers, and wood stains. First, glycol monoethers are produced from ethylene oxide or propylene oxide with alcohol, which are then esterified with acetic acid. The three major products are ethylene glycol monoethyl ether acetate (EEA), ethylene glycol monobutyl ether acetate (EBA), and propylene glycol monomethyl ether acetate (PMA, more commonly known as PGMEA in semiconductor manufacturing processes, where it is used as a resist solvent). This application consumes about 15% to 20% of worldwide acetic acid. Ether acetates, for example EEA, have been shown to be harmful to human reproduction. 

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