Acetaldehyde is used as intermediate for syntheses of bulk chemicals, e.g. ethyl acetate, acetic acid, acetic anhydride, isooctylalcohol, pentaerythrite, pyridines, etc. For specific dyes, e.g. C.I. 46040 Basic Yellow 9. Product Data Sheet
Breathing vapors will be irritating and may cause nausea, vomiting, headache, and unconsciousness. Contact with eyes may cause burns and eye damage. Skin contact from clothing wet with the chemical causes burns or severe irritation.
Acetaldehyde enters your body when you breathe air containing it. It can also enter your body when you eat food or drink liquid containing acetaldehyde. When you drink alcohol, your body makes acetaldehyde when it processes the alcohol.
The effect of acetaldehyde on your health depends on how much is in your body, how long you were exposed, and how often you were exposed. The way it affects you will also depend on your health. Another factor is the condition of the environment when you were exposed.
Breathing acetaldehyde for short periods can hurt your lungs. Acetaldehyde can also hurt your heart and blood vessels.
Contact with acetaldehyde liquid or vapor can hurt the skin and eyes.
It is not known if breathing, drinking or eating small amounts of acetaldehyde over long periods will hurt you. Some animal studies show that acetaldehyde can hurt a growing fetus. Other studies on animals show that breathing acetaldehyde can severely damage the lungs and cause cancer. Repeated exposure to acetaldehyde in the air may cause cancer in humans.
When you drink alcohol, your liver turns acetaldehyde into an acid. Some of the acetaldehyde enters your blood, damaging your membranes and possibly causing scar tissue. It also leads to a hangover, and can result in a faster heartbeat, a headache or an upset stomach.
The brain is most affected by acetaldehyde poisoning. It causes problems with brain activity and can impair memory. Acetaldehyde can cause amnesia, which is the inability to remember things. This is a common effect for people who drink too much alcohol.
Several production methods are used to produce ethanal.
(1) Direct oxidation of ethylene.
Ethylene and oxygen passed the catalysts containing palladium chloride, copper chloride, hydrochloric acid and water .Coarse acetaldehyde can be synthesyed by this one-Step direct oxidation process. Then, after a distillation process, the final product was obtained.
(2) Ethanol oxidation.
Under the 300-480 ℃, the air oxydehydrogenation process of ethanol vapor took place to produce acetaldehyde by using silver, copper or silver-copper alloy mesh as catalyst.
(3) Direct hydration of ethyne.
Under the effect of mercury catalyst or mercury free catalyst, the direct hydration reaction of acetylene and water was used to produce acetaldehyde. Due to the toxicity of mercury, this method has been gradually replaced by other methods.
(4) Ethanol dehydrogenation
Under the effect of copper catalyst with the addition of cobalt, chromium, zinc or other compounds, ethanol dehydrogenation took place to produce acetaldehyde.
(5) Saturated hydrocarbon oxidation.
Material Consumption Quota: one ton product of acetaldehyde costs 610kg ethyne(99%) by direct hydration of ethyne method; 1200kg ethanol (95%) by ethanol oxidation method; 710kg ethylene(99%) and 300m3 oxygen（99%） by ethylene oxidation method (one-step).
(6) Acetaldehyde can be prepared by ethylene oxidation.
Acetaldehyde can be prepared by gas phase hydrogenation of Ethanol.
Acetaldehyde can be prepared by simultaneous destructive distillation calcium acetate and calcium formate.
ethanal can be prepared by adduct reaction of acetylene and water.
Acetaldehyde is a highly flammable, volatile colourless liquid. It has a characteristic, pungent,
and suffocating odour and is miscible in water. Acetaldehyde is ubiquitous in the
ambient environment. It is an intermediate product of higher plant respiration and formed
as a product of incomplete wood combustion in fireplaces and woodstoves, burning of
tobacco, vehicle exhaust fumes, coal refining, and waste processing. Exposures to acetaldehyde
occur during the production of acetic acid and various other industrial chemical
substances, for instance, manufacture of drugs, dyes, explosives, disinfectants, phenolic
and urea resins, rubber accelerators, and varnish.
Acetaldehyde is usually purified by fractional distillation in a glass helices-packed column under dry N2, discarding the first portion of distillate. Or, it is shaken for 30minutes with NaHCO3, dried with CaSO4 and fractionally distilled at 760mm through a 70cm Vigreux column (p 11). The middle fraction is collected and further purified by standing for 2hours at 0o with a small amount of hydroquinone (free radical inhibitor), followed by distillation [Longfield & Walters J Am Chem Soc 77 810 1955]. [Beilstein 1 IV 3094.]
ChEBI: The aldehyde formed from acetic acid by reduction of the carboxy group. It is the most abundant carcinogen in tobacco smoke.
- Acetaldehyde can also be used as an odorant, and it found in nature in many foods such as ripe fruits, cheese and heated milk. acetaldehyde occurs naturally during fermentation, and low levels of acetaldehyde are to be found in certain foods. It is mainly used for preparation of citrus, apple, cream type essence, etc.
- Acetaldehyde is mostly used in acetic acid industry. Butanol and octanol are also the important derivatives of the acetaldehyde in the past. Nowadays, butanol and octanol are prepared by Propylene carbonyl synthesis method.
- Acetaldehyde is a very important raw material in the production of a large number of chemical products, for example paint binders in alkyd paints and plasticizers for plastics. Acetaldehyde is also used in the manufacture of construction materials, fire retardant paints and explosives, while its uses within the pharmaceutical industry include the manufacture of sedatives and tranquilisers, among other things. Acetaldehyde can also be used as a raw material in the manufacture of acetic acid, another platform chemical with many applications.
- Acetaldehyde is also used to produce pentaerythritol, peracetic acid, pyridine and its derivatives. Domestically produced acetaldehyde is mainly used as intermediate for the production of acetic acid. Only a small amount is used for the production of pentaerythritol, butanol, trichloroacetaldehyde, trimethylolpropane, etc.
- Acetaldehyde is primarily used to produce other chemicals, including acetal, Crotonaldehyde, acetic acid peroxide, hydroxyl acrylic nitrile, trichloroacetaldehyde, ethyl acetate, pentaerythritol, acetic anhydride, acetic acid, Glyoxal, phenyl acrolein, acetal, methyl ethylamine , diethylamine, α-Alanine, pyridine, α-methylpyridine, β-methylpyridine, γ-methylpyridine, etc.
Acetaldehyde, also called ethanal, is the simplest aldehyde (CH3CHO). Acetaldehyde is a colourless and volatile liquid made by the catalytic oxidation of ethanol, with a sharp and fruity odour.It is widely used industrially as a chemical intermediate.Acetaldehyde is also a metabolite of sugars and ethanol in humans,is found naturally in the environment, and is a product of biomass combustion.
Acetaldehyde is primarily used as an intermediate in the manufacture of a range of chemicals, perfumes, aniline dyes, plastics and synthetic rubber and in some fuel compounds. Acetaldehyde is an important reagent used in the manufacture of dyes, plastics, and many other organic chemicals.
In the presence of acids it forms the cyclic polymers paraldehyde (CH3CHO)3, and metaldehyde (CH3CHO)4. The former is used as a hypnotic, and the latter as a solid fuel for portable stoves and as a poison for snails and slugs.
Acetaldehyde is also used in the manufacture of disinfectants, drugs, perfumes, explosives, lacquers and varnishes, photographic chemicals, phenolic and urea resins, rubber accelerators and antioxidants, and room air deodourizers. It is also used as a synthetic flavouring substance, food preservative and as a fragrance.
figure 1 Acetaldehyde 2d structural formula
manufacture of paraldehyde, acetic acid, butanol, perfumes, flavors, aniline dyes, plastics, synthetic rubber; silvering mirrors, hardening gelatin fibers. Flavoring agent in foods and beverages. Fumigant for storage of apples and strawberries.
Acetaldehyde, as its metabolite, is responsible for many
of the effects of ethanol, such as hepatic or neurological
toxicity. A case of contact allergy was reported in
the textile industry, where dimethoxane was used as a
biocide agent in textiles, and its degradation led to
Air & Water Reactions
Highly flammable. Easily oxidized by air to form unstable peroxides which may explode. Forms explosive mixture with air above 100°C (30-60% of the vapor in air) owing to formation of peroxyacetic acid [White, A. G. et al., J. Soc. Chem. Ind., 1950, 69, p. 206]. Soluble in water.
Hazardous Substances Data Bank (HSDB)
Acetaldehyde has been classified by the International Agency for Research on Cancer (IARC) as Group 2B, possibly carcinogenic to humans, based on evidence in animals.Acetaldehyde is a respiratory tract carcinogen in experimental animals, especially of the nasal mucosa in rats and of the larynx in hamsters.
There is inadequate evidence for the carcinogenicity of acetaldehyde in humans. One small study of workers manufacturing several types of aldehydes found increased risk of bronchial tumours, but workers were exposed to many other chemicals in addition to acetaldehyde.Three other studies on the carcinogenicity of alcoholic beverages found that people who developed cancer after heavy alcohol use had genetic differences and higher concentrations of acetaldehyde in their blood compared to those who didn't develop cancer.Further study is required to establish a causal relationship.
Acetaldehyde can cause respiratory and eye irritation and in severe cases, lung edema. It also exacerbates the effects of alcohol and is a central nervous system depressant.
65 ml of 0.5 mol/L hydroxylamine hydrochloride and 50.0 ml of triethanolamine were added to a fixed pressure-heat resistant bottle with good sealing property. A slow nitrogen flow is fed into the bottle through a glass tube slightly above the liquid surface for 2 min to exhaust the air. About 600 mg of the sample, accurately weighed, was sealed in one ampoule bottle and put in the above mixture. Several short glass rods with the diameter of about 8 mm were added to the bottle. After covering the cork, the bottle was strongly shaken to break the ampoule. Then keep the reaction for 30 min at room temperature, shaking the bottle from time to time. Remove the cork after cooling if necessary. The whole process should be careful in order to avoid the loss of the product. The above system was then titrated by certain amount of 0.5 mol/L sulfuric acid to cyan end point. At the same time a blank titration was conducted. Each 0.5 mol/L sulfur acid was equivalent to 22.03 mg acetaldehyde (C2H4O).
As a flavor ingredient
CoE: Approved. Bev.: 23 ppm; Food: 20 ppm
FDA: 21 CFR 182.60, 582.60; 27 CFR 19.460, 21 et seq.
FDA (other): n/a
JECFA: ADI: Acceptable. No safety concern at current levels of intake when used as a flavoring agent (1997).
Reported uses (ppm): (FEMA, 1994)
Reported found in oak and tobacco leaves; in the fruital aromas of pear, apple, raspberry, strawberry and pineapple; in the distillation waters of Monarda punctata, orris, cumin, chenopodium; in the essential oils of Litsea cubeba, Magnolia grandiflora, Artemisia brevifolia, rosemary, balm, clary sage, Mentha arvensis, daffodil, bitter orange, camphor, angelica, fennel,mustard, Scotch blended whiskey, Japanese whiskey, rose wine, blackberry brandy and rum.
Acetaldehyde is used as a general solvent in organic and polymer chemical reactions. It also plays a role in fruit and food quality, ripening and deterioration.
Acetaldehyde undergoes a vigorously exothermic condensation reaction in contact with strong acids, bases or traces of metals. Can react vigorously with oxidizing reagents such as dinitrogen pentaoxide, hydrogen peroxide, oxygen, silver nitrate, etc. Contamination often leads either to reaction with the contaminant or polymerization, both with the evolution of heat. Can react violently with acid anhydrides, alcohols, ketones, phenols, ammonia, hydrogen cyanide, hydrogen sulfide, halogens, phosphorus, isocyanates, concentrated sulfuric acid, and aliphatic amines. Reactions with cobalt chloride, mercury(II) chlorate or perchlorate form sensitive, explosive products [Sax, 9th ed., 1996, p. 5]. An oxygenation reaction of Acetaldehyde in the presence of cobalt acetate at -20°C exploded violently when stirred. The event was ascribed to peroxyacetate formation [Phillips B. et al., J. Am. Chem. Soc., 1957, 79, p. 5982].
A clear colorless liquid with a pungent choking odor. Flash point -36°F. Boiling point 69°F. Density 6.5 lb / gal. Vapors are heaver than air and irritate the mucous membranes and especially the eyes. Used to make other chemicals.
Colourless clear liquid