Ethanol, acetaldehyde produced from

Acetaldehyde, produced from the metabolism of ethanol, may also be responsible for localized cancers, brain damage in prenatal infants, and growth suppression (in chicken embryos). Acetaldehyde, as a direct result of ethanol metabolism in the body, has been implicated in alcoholic cardiomyopathy and cancer of the digestive tract. The levels of acetaldehyde in blood are directly correlated with ethanol consumption. 

Ethanol is an "antivitamin" that decreases the cellular content of almost every coenzyme. For example, ethanol inhibits the absorption of thiamine, and acetaldehyde produced from ethanol oxidation displaces pyridoxal phosphate from its protein binding sites, thereby accelerating its degradation. 

The acetaldehyde produced from ethanol is highly reactive, toxic, and immunogenic. In Al Martini and other patients with chronic alcoholism, acetaldehyde is responsible for much of the liver injury associated with chronic alcoholism... 

The acetaldehyde produced from ethanol in the liver is further oxidized to acetic acid, which is eventually converted to carbon dioxide and water in the citric acid cycle. However, the intermediate products can cause considerable damage while they are present within the cells of the hver. 

In a process which is now largely of historical interest, 1-butanol has been produced from ethanol [64-17-5] via successive dehydrogenation (to acetaldehyde [75-07-0]) condensation (to crotonaldehyde [4170-30-3]) and hydrogenation. 

Calcium carbide can be treated with water to produce acetjiene from which other organic compounds, eg, ethanol, acetaldehyde, may be obtained (6) (see... 

Acetaldehyde. Until the early 1970s, the maia use of iadustrial ethanol was for the production of acetaldehyde [75-07-0]. By 1977, the ethanol route to acetaldehyde had largely been phased out ia the United States as ethylene and ethane became the preferred feedstocks for acetaldehyde production (286—304). Acetaldehyde usage itself has also changed two primary derivatives of acetaldehyde, acetic acid, and butanol, are now produced from feedstocks other than acetaldehyde. Acetaldehyde is stiU produced from ethanol ia India. 

The vapor-phase esterification of ethanol has also been studied extensively (363,364), but it is not used commercially. The reaction can be catalyzed by siUca gel (365,366), thoria on siUca or alumina (367), zirconium dioxide (368), and by xerogels and aerogels (369). Above 300°C the dehydration of ethanol becomes appreciable. Ethyl acetate can also be produced from acetaldehyde by the Tischenko reaction (370—372) using an aluminum alkoxide catalyst and, with some difficulty, by the boron trifluoride-catalyzed direct esterification of ethylene with organic acids (373). 

Different routes for converting biomass into chemicals are possible. Fermentation of starches or sugars yields ethanol, which can be converted into ethylene. Other chemicals that can be produced from ethanol are acetaldehyde and butadiene. Other fermentation routes yield acetone/butanol (e.g., in South Africa). Submerged aerobic fermentation leads to citric acid, gluconic acid and special polysaccharides, giving access to new biopolymers such as polyester from poly-lactic acid, or polyester with a bio-based polyol and fossil acid, e.g., biopolymers . 

At the lowest concentrations of 2-propanol, 10"2 M, there is reasonable agreement between calculated and experimental results. These results then are consistent with the assumption that acetone is the only oxidation product from the radical produced from 2-propanol in aqueous solution containing oxygen. It has similarly been shown (23) that acetaldehyde is the only organic oxidation product in the radiation-induced oxidation of aqueous ethanol. However, our experiments indicate that in... 

Carbonyl double bonds can also be photoelectrochemically reduced ZnS sols prepared from cold oxygen-free aqueous solutions ofZnSO4 and NajS induce efficient photodisproportionation of aldehydes, i.e., a photo-Canizzaro reaction Thus, acetaldehyde produces ethanol and acetic acid, together with smaller quantities of biacetyl and acetoin, Eq. (37). 

Acetaldehyde is a useful huilding block for acetic aod, acetic anhydride. and chloral Ills currently produced from ethylene, ethanol, propane, and butane Production from acetylene appear to be outdated... 

Fresh feed (pure ethanol) is blended with a recycle stream (95 mole% ethanol and 5% acetaldehyde), and the combined stream is heated and vaporized, entering the reactor at 280 C. Gases leaving the reactor are cooled to -40 C to condense the acetaldehyde and unreacted ethanol. Off-gas from the condenser is sent to a scrubber, where the uncondensed organic compounds are removed and hydrogen is recovered as a by-product. The condensate from the condenser, which is 45 mole% ethanol, is sent to a distillation column that produces a distillate containing 97 mole% acetaldehyde and a bottoms product that constitutes the recycle blended with fresh feed to the process. The production rate of the distillate is 1000 kg/h. The pressure throughout the process may be taken as 1 atm absolute. 

An aqueous solution containing ethyl alcohol in water is fermented to produce dilute acetic acid. The feed mixture (the ethanol solution and the bacteria that make the fermentation occur) and a>r are fed at a temperature Tq. The product solution contains ethanol, acetaldehyde (CH CHO), acetic acid, and water. All liquid and gaseous effluents are at temperature T. The variables involved in the process are n (mol feed solution), x (mol eihanol/mol feed solution), n i (mol air fed). (percent excess air),nah, (gram-moles of ethanol, acetaldehyde, acetic acid, and water, respectively, in the product mixture), Hox, n (gram-moles of oxygen and nitrogen, respectively, emerging from the reactor), 7 , 7, and 0(kJ heat transferred . 

Methyl ketones can be distinguished from other ketones by the iodoform test. The methyl ketone is treated with iodine in a basic solution. Introduction of the first iodine atom increases the acidity of the remaining methyl protons, so halogenation stops only when the triiodo compound has been produced. The base then allows the relatively stable triiodomethyl carban-ion to leave and a subsequent proton transfer gives iodoform, a yellow crystalline solid of mp 119-123°C. The test is also positive for fragments easily oxidized to methyl ketones, such as CH3CHOH— and ethanol. Acetaldehyde also gives a positive test because it is both a methyl ketone and an aldehyde. 

Acetaldehyde is produced from the metabolism of ethanol in the body. 

The present work deals with ethanol oxidation which was performed in a flow reactor under lean conditions. Catalysts were evaluated by studying their light-off behaviour and by determining the amount of acetaldehyde produced during the temperature programmed experiment from ambient temperature to 500°C. 

During ageing, the andiocyanins can react with other compounds produced from the yeast like pyruvic acid (Fulcrand et al. 1998), acetaldehyde (Es Safi et al. 1999) or odier aldehydic compounds such as furfural and hydroxymethyl furfural coming from oak wood (Es-Safi et al. 2002). In order to assess the possibility for acetaldehyde to be produced by oxidation of ethanol (Wildenradt and Singleton 1974) and to study the structures of compoimds formed, the model solution previously used for copigmentation studies (Mirabel et al. 1999) were stored for ten weeks in the dark at ambient temperature. Two model solutions (pH3.75) containing 0 or 12% Ethanol were analyzed by LC/MS after 10 weeks of incubation. 

Although acetaldehyde may generally be more economically produced from acetylene by hydration, the high yields that may be obtained by the dehydrogenation of ethanol show the excellent directive powers of the copper catalysts for this reaction. By operating at temperatures below... 

Although alcohol has been produced by the hydrogenation of acetaldehyde obtained from the hydration of acetylene, this source is relatively unimportant ordinarily. It does, however, furnish a means for the synthesis of ethanol from such sources of carbon as calcium carbide, methane, the carbon arc, etc., which might become of importaice during periods of war, or in locations where very cheap electric power is available. Experiments on a technical scale78 in Switzerland have shown the process to be successful but at a cost too high to make the process competitive. 

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