| Chemical Abstract Number (CAS #) |
123386
|
|---|
| Synonyms | Propionaldehyde |
|---|
| Analytical Methods |
EPA Method 554 |
|---|
EPA Method 8315 |
| Molecular Formula | C3H6O |
|---|
| Use | Mfr of polyvinyl & other plastics; synthesis of rubber chemicals; disinfectant; preservative
INTERMEDIATE IN THE MFR OF TRIMETHYLOLETHANE FOR USE IN ALKYD RESIN
SYSTEMS &, IN CERTAIN CASES, IT IS OXIDIZED TO PROPIONIC ACID & REDUCED
TO PROPYL ALCOHOL; IN MEDICINAL & AGRICULTURAL CHEMICAL
PREPARATIONS.
|
|---|
| Apparent Color | COLORLESS LIQUID
|
|---|
| Odor | SUFFOCATING, FRUITY ; CHARACTERISTIC ODOR SIMILAR TO
ACETALDEHYDE ; Pungent, unpleasant ; Choking odor
|
|---|
| Boiling Point | 49 DEG C @ 760 MM HG; 47 DEG C @ 740 MM HG; 45 DEG C @ 687 MM HG
|
|---|
| Melting Point | -81 DEG C
|
|---|
| Molecular Weight | 58.08
|
|---|
| Density | 0.8071 @ 20 DEG C/4 DEG C; 0.8432 @ 0 DEG C/4 DEG C; 0.8192 @ 9.7 DEG C/4
DEG C; 0.7898 @ 33 DEG C/4 DEG C
|
|---|
| Odor Threshold Concentration | 1 ppm.
|
|---|
| Sensitivity Data | THE VAPOR MAY CAUSE RESPIRATORY IRRITATION BUT IS NOT A STRONG
ENOUGH IRRITANT OF EYES OR RESPIRATORY TRACT TO BE CONSIDERED
SIGNIFICANT FACTOR IN SMOG.
WHILE IT IS QUITE TOXIC BY INHALATION, IT IS ONLY MODERATELY TOXIC BY
INGESTION OR ABSORPTION THROUGH SKIN.
|
|---|
| Environmental Impact | Propionaldehyde is a highly volatile compound that is emitted to air from arboreous
plants. Evidence suggests that it is photolytically produced by UV irradiation of dissolved organic
materials in seawater. Anthropogenic releases to the environment may occur at sites where it is
produced or used as a chemical intermediate in the manufacture of propionic acid, polyvinyl and
other plastics in the synthesis of rubber chemicals and as a disinfectant and preservative.
Atmospheric emissions result from the combustion of wood, gasoline, diesel fuel and
polyethylene. Hence, municipal waste incinerators also release it to ambient air. Effluents of alkyd
resin production have been shown to contaminate surface and ground waters, and land with
propionaldehyde. Photolysis, hydrolysis, adsorption and bioconcentration of propionaldehyde are
not expected to be important environmental fate processes. In terrestrial and aquatic
environments, propionaldehyde will biodegrade to its corresponding carboxylic acid, which then
undergoes mineralization. Volatilization from soil and water is also expected to be significant. The
volatilization half-lives from a model river and a model pond, the latter considers the effect of
adsorption, have been estimated to be 11 hrs and 5 days, respectively. In the atmosphere,
propionaldehyde exists almost entirely in the vapor-phase and reactions with photochemically
generated hydroxyl radicals should be important (average half-life of 19.6 hrs). Removal by wet
deposition can also occur. The most probable route of human exposure to propionaldehyde is by
inhalation or ingestion. Atmospheric workplace exposures have been documented and monitoring
data indicate that it is a widely occurring atmospheric pollutant. Nonoccupational exposures may
occur among coffee drinkers or populations with contaminated drinking water supplies.
|
|---|
| Environmental Fate | TERRESTRIAL FATE: Direct photolysis and hydrolysis are not expected to be
important fate processes of propionaldehyde in soils. Biodegradation and volatilization are
expected to be the dominant removal mechanisms from terrestrial environments. Propionaldehyde
biodegrades to its corresponding carboxylic acid, which then undergoes mineralization . Both
the vapor pressure and Henry's Law constant indicate volatilization of propionaldehyde from soil
should be significant. Adsorption should not compete with volatilization; calculated Koc values (4
to 50) indicate a very high mobility class in soil(6).
AQUATIC FATE: Direct photolysis and hydrolysis of propionaldehyde in natural waters
are not expected to be important fate processes. The dominant removal mechanisms of
propionaldehyde from aquatic systems are expected to be biodegradation and volatilization.
Propionaldehyde biodegrades to its corresponding carboxylic acid, which then undergoes
mineralization . Based on a Henry's Law constant of 7.34X10-5 atm-cu m/mole at 25 deg C ,
the volatilization half-life from a model river has been estimated to be 11 hrs(2,SRC). The
volatilization half-life from a model pond, which considers the effect of adsorption, can be
estimated to be about 5 days(5,SRC). Based on estimated values of log BCF (-0.30 to 0.22) and
Koc (4 to 50), propionaldehyde is not expected to bioconcentrate or partition from the water
column to organic matter contained in sediments and suspended solids.
ATMOSPHERIC FATE: Based on a vapor pressure of 317 mm Hg at 25 deg C ,
propionaldehyde is expected to exist almost entirely in the vapor phase in ambient air .
Propionaldehyde weakly absorbs UV light in the environmentally significant range, >290 nm
and probably will not undergo direct photolysis in the atmosphere. However, vapor phase
reactions with photochemically produced hydroxyl radicals in the atmosphere should be
important. A rate constant for the hydroxyl radical reaction with propionaldehyde of 1.96X10-11
cu cm/molecule-sec at 25 deg C corresponds to an atmospheric half-life of 19.6 hrs at an
atmospheric concn of 5X10 5 hydroxyl radicals per cu cm. Removal by wet deposition can also
occur(5-6).
|
|---|
| Drinking Water Impact | DRINKING WATER: Propionaldehyde was one of the most frequently occurring
organic compounds found in drinking water supplies according to the US National Organic
Reconnaissance Survey; however, levels were not reported . It was also qualitatively listed as a
contaminant of drinking water supplies in the UK .
SEAWATER WATER: Surface sea water samples from off the coast of Florida contained
propionaldehyde at trace concns .
RAINWATER: Trace quantities of propionaldehyde were detected in fog, ice fog, cloudwater
and rainwater in the air of Los Angeles, CA . It was also qualitatively detected in precipitation
at Hanover, Germany in 1989-90 .
EFFL: Propionaldehyde is a product of wood , gasoline(1-2), diesel fuel and polyethylene
combustion. Propionaldehyde was detected in the gaseous phase among the atmospheric
emissions of 4 gasoline fuels upon combustion at average concentrations of 2.4, 2.8, 4.9, and 3.3
ug/km . It was also identified as a stack emission from municipal waste incinerators(7).
Propionaldehyde was emitted at a rate of 0.002 g/min from burning green ash wood; it was first
detected 18 min after the flames disappeared in the smolder stage of a wood stove fire . An
identical test with red oak wood used as fuel emitted propionaldehyde at rates of 0.050 and 0.009
g/min for the first 2 min of burn, and thereafter, respectively . Average concentrations for
various wood types were 0.15 g/kg (jack pine), 0.040 g/kg (cedar), 0.017 g/kg (red oak), 0.012
g/kg (red oak), 0.088 g/kg (red oak), 0.020 g/kg (green ash), and 0.014 g/kg (green ash) .
Wastewater from an alkyd resin production facility contained propionaldehyde; accidental releases
from effluent pipes contaminated the underlying soil and ground water(6).
|
|---|
