| Chemical Abstract Number (CAS #) |
75070
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| Synonyms | Acetaldehyde |
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Ethanal | Ethyl aldehyde | Acetic aldehyde |
| Analytical Methods |
EPA Method 554 |
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EPA Method 8315 |
| Molecular Formula | C2H4O |
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| Use | IN PRODN OF WIDE RANGE OF ORG CHEMICALS; IMPORTANT CHEMICAL
INTERMEDIATE.
SYNTHETIC FLAVOR & ADJUVANT
MFR SYNTHETIC RESINS, DYES
MFR PARALDEHYDE, ACETIC ACID, BUTANOL, PERFUMES, ANILINE DYES,
PLASTICS, SYNTHETIC RUBBER, SILVERING MIRRORS, HARDENING GELATIN
FIBERS.
SYNTHETIC FLAVOR INGREDIENT USEFUL IN ALL FRUITS FOR LIFT; ESPECIALLY
ORANGE, APPLE, AND BUTTER.
CHEM INT FOR ACETIC ACID & PERACETIC ACID
CHEM INT FOR PYRIDINE & PYRIDINE BASES
CHEM INT FOR PENTAERYTHRITOL & 1,3-BUTYLENE GLYCOL
CHEM INT FOR CHLORAL & GLYOXAL
MONOMER FOR POLYACETALDEHYDE & COMONOMER FOR COPOLYMERS
ALCOHOL DENATURANT
OXIDN PROMOTER IN MFR OF TEREPHTHALIC ACID
Intermediate for pesticides and photographic formulations.
Chemical intermediate for ester production, particularly ethyl acetate and isobutyl acetate. Other
significant derivatives of acetaldehyde include lactic acid.
currently an important intermediate in the production of acetic acid, acetic anhydride, ethyl
acetate, peracetic acid, pentaerythritol, chloral, glyocal, alkylamines, and pyridines.
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| Consumption Patterns | CHEM INT FOR ACETIC ACID, 61%; CHEM INT FOR PYRIDINE & PYRIDINE
BASES, 9%; CHEM INT FOR PERACETIC ACID, 8%; CHEM INT FOR
PENTAERYTHRITOL, 7%; CHEM INT FOR 1,3-BUTYLENE GLYCOL, 2%; CHEM INT
FOR CHLORAL, 1%; OTHER USES (INCL EXPORTS), 12% (1982)
USA acetaldehyde demand in 1978 was 1.30 billion lb; 1979, 1.35 billion lb; 1983, 1.58 billion lb.
Acetic acid, 50%; exports, 14%; miscellaneous including lactic acid and croton aldehyde, 13%;
pyridine and pyridine bases, 8%; pentaerythritol, 7%; peracetic acid, 6%; 1,3-butyleneglycol, 2%
(1986).
A survey of USA industry on the use of food additives reported that 8.6 thousand kg of
acetaldehyde were used in 1976 as an important component of many flavors added to foods, such
as milk products, baked goods, fruit juices, candies, desserts & soft drinks, at usual levels up to
0.047% (1976).
Acetaldehyde is one of the denaturants approved for use (at a level of 10 lb/100 gal (12 g/l) of
alcohol) in the USA in specially denatured alcohol Formula No 29. Although the volume of this
formula used in the USA each year is published, no information is available on the amount made
with acetaldehyde.
Synthetic pyridine derivatives, peracetic acid, acetate esters by the Tischenko route, and
pentaerythritol accout for 40% of acetaldehyde demand. all of these materials may be prepared
from alternative processes.
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| Apparent Color | COLORLESS LIQUID ; Colorless gas
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| Odor | Pungent, suffocating odor that is slightly fruity when diluted.
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| Boiling Point | 21 DEG C
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| Melting Point | -123.5 DEG C
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| Molecular Weight | 44.05
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| Density | 0.788 AT 16 DEG C/4 DEG C
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| Odor Threshold Concentration | Recognition in air= 2.1x10-1 ppm (chemically pure)
Odor low: 0.0002 mg/cu m; Odor high: 4.14 mg/cu m
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| Sensitivity Data | Man: eye irritation sensitive persons: 25 ppm 15 min; eye irritation: 50 ppm 15 min;
irritation of respiratory tract: 134 ppm 30 min; irritation of nose and throat: 200 ppm 15 min.
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| Environmental Impact | Acetaldehyde is a natural product of combustion and photooxidation of commonly found
hydrocarbons in the atmosphere. It is also photochemically produced in surface water.
Acetaldehyde occurs naturally in many foods. Additionally it is an important industrial chemical
and may be released into the air or in wastewater during its production and use. If released into
water it will rapidly biodegrade and volatilize (half-life 3 hrs for a typical river). If spilled on land
it will also rapidly evaporate and leach into the ground where it will biodegrade. In the
atmosphere it will degrade in a matter of hours by reaction with hydroxyl radicals and photolysis.
Human exposure will be principally by inhalation of ambient air especially in urban areas or near
sources of combustion and from the ingestion of foods naturally containing acetaldehyde.
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| Environmental Fate | TERRESTRIAL FATE: If released on soil, acetaldehyde will rapidly evaporate since its
vapor pressure is 740 torr at ambient temperature. Some may leach into the ground where it is not
expected to adsorb appreciably except by montmorillonite clay and it also is expected to
biodegrade.
AQUATIC FATE: If released into water, acetaldehyde will be rapidly lost by volatilization
(half-life 9.3 hrs for a typical river and rapidly biodegrade).
ATMOSPHERIC FATE: If released into the atmosphere, acetaldehyde will be involved in a
complex chain of photochemical reactions. It will degrade with a half-life on the order of hours
principally by reaction with hydroxyl radicals and photolysis.
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| Drinking Water Impact | DRINKING WATER: 10 city survey (representing different sources and types of
contamination of raw water supply) detected in 4 of 10 supplies with levels of 0.1 ppb in the
water supplies of Philadelphia and Seattle(1,2). Detected, not quantified in the drinking water of
New Orleans , Cincinnati, Miami, Ottuma (Iowa) and Durham(NC) . Median concn of
acetaldehyde in drinking water from 35 US treatment plant was 2.7, 2.6 and 1.8 ppb in Summer
1988, Fall 1988, and Winter 1989, respectively(7). SURFACE WATER: Detected, not quantified
in the Mississippi River at New Orleans(6). Surface seawater off the southwest coast of Florida -
19 nM, max at mid afternoon and 2 nM at 6 AM(8). OTHER: Ice fog (Fairbanks, AK) -
0.007-0.13 ppm; Rain (5 sites-California) 0-0.11 ppm with 2 of 6 sites positive; Clouds
(California) 0-0.59 ppm; Mist (2 sites-California) 0.10-0.11 ppm; Fog (4 sites-California) 0-0.17
ppm . Precipitation (Hannover, Germany) 1.5-20.5 ppb, 12.0 ppb, mean(9).
RAINWATER: Analysis of rain, mist and dew samples, collected in Petten (The Netherlands)
during 1987 and 1988, showed acetaldehyde levels of 5 to 185 ug/l for rain (n= 8), 15 and 200
ug/l for dew and 30 ug/l for mist.
EFFL: Gasoline engine exhaust 0.8-4.9 ppm . Diesel exhaust 3.2 ppm . Cars with catalytic
converters 13.3-40.8 mole%, cars without catalytic converters 7.2-12.3 mole% . Effluent from
chemical plants into Mobile River (Alabama) and Pacolet and Enoree River (South Carolina) .
Effluent from sewage treatment plants - although it has not been determined whether the
acetaldehyde was in the influent or formed as a product of microbial degradation .
Coffee-roasting operations (14-22 mg/cu m), from a lithographic plate coater (0.5-4.1 mg/cu m),
from an automobile-spray booth (2.5-3.4 mg/cu m), from plants mfr acrylic acid, & from a
fat-rendering plant at levels of 3.4-6.8 mg/cu m.
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