Acetaldehyde

  • Ethyl aldehyde
  • Acetic aldehyde
  • Ethanal
  • Acetylhydride
  • Aldehyde
  • AAD
Formula
CH3CHO
Structure
Description
Highly volatile, colorless liquid with a penetrating, pungent, suffocating odor that is somewhat fruity and quite pleasant in low concentrations.
Uses
Acetaldehyde is used mainly as a chemical intermediate in the production of acetic acid. It is also used to produce many other chemicals. It is used in the manufacture of paraldehyde, metaldehyde, other polymers, plastics, synthetic rubber and resins, cosmetics, perfumes, pesticides and pharmaceuticals; in the silvering of mirrors; in leather tanning; in the hardening of gelatin fibres; as a denaturant for alcohols; in fuel compositions; in glue and casein products; as a preservative for fish and fruit; as a synthetic flavouring agent; as a food additive; in the paper industry; and as a laboratory chemical.

Registry Numbers and Inventories.
CAS
75-07-0
EC (EINECS/ELINCS)
200-836-8
EC Index Number
605-003-00-6
EC Class
Extremely flammable; Carcinogenic Category 3; Irritant
R 12 36/37 40
S 16 33 36/37
RTECS
AB1925000
RTECS class
Tumorigen; Mutagen; Reproductive Effector; Human Data; Primary Irritant
UN (DOT)
1089
Merck
12,37
Beilstein/Gmelin
505984
Beilstein Reference
4-01-00-03094
RCRA
U001
EPA OPP
202300
Swiss Giftliste 1
G-1024
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C2H4O
Formula mass
44.05
Melting point, °C
-123
Boiling point, °C
20.1
Vapor pressure, mmHg
965 (25 C)
Vapor density (air=1)
1.52
Saturation Concentration
Extremely high; gas at room temperature.
Odor Threshold Odor threshold Recognition 0.21 ppm
Critical temperature
193
Critical pressure
54.8
Density
0.780 g/cm3 (20 C)
Solubility in water
Miscible
Viscosity
0.2456 cp at 15C
Surface tension
21.2 g/s2 at 20 C
Refractive index
1.3316 (20 C)
Partition coefficient, pKow
-0.16
Thermal expansion
0.0021/K at 20 C
Heat of vaporization
25.7 kJ/mol
Heat of combustion
-1169 kJ/mol

Hazards and Protection.
Storage
Keep away from heat, sparks, and flame. Keep away from sources of ignition. Keep from freezing. Store in a tightly closed container. Keep from contact with oxidizing materials. Keep away from strong acids. Refrigerator/flammables. Keep away from reducing agents. Do not expose to air. After opening, purge container with nitrogen before reclosing. Periodically test for peroxide formation on long-term storage. Addition of water or appropriate reducing materials will lessen peroxide formation. Store under an inert atmosphere.
B2 D2A
Handling
Use only in a well ventilated area. Ground and bond containers when transferring material. Do not breathe dust, vapor, mist, or gas. Do not get in eyes, on skin, or on clothing. Empty containers retain product residue, (liquid and/or vapor), and can be dangerous. Keep container tightly closed. Avoid contact with heat, sparks and flame. Do not ingest or inhale. Handle under an inert atmosphere. Store protected from air. This product may be under pressure; cool before opening. If peroxide formation is suspected, do not open or move container. Do not pressurize, cut, weld, braze, solder, drill, grind, or expose empty containers to heat, sparks or open flames.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to minimize contact with skin.
Respirators
Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks
Absorb spill with inert material, (e.g., dry sand or earth), then place into a chemical waste container. Use water spray to dilute spill to a non-flammable mixture. Avoid runoff into storm sewers and ditches which lead to waterways. Use water spray to disperse the gas/vapor. Remove all sources of ignition. Use a spark-proof tool. Place under an inert atmosphere.
Disposal code
7
Stability
Unstable in air May undergo autopolymerization. Forms explosive peroxides on prolonged storage and exposure to air.
Incompatibilities
Air, acid anhydrides, alcohols, ketones, phenols, ammonia, hydrogen cyanide, hydrogen sulfide, halogens, phosphorus, isocyanates, stong alkalies, amines, cobalt chloride, mercury (II) chlorate, mercury (II) perchlorate, trace metals, acids, acetic acid, sulfuric acid, strong oxidizing agents, strong reducing agents, strong bases, strong acids.
Decomposition
Carbon monoxide, carbon dioxide, methane.

Fire.
Flash Point,°C
-38
Autoignition, °C
140
Upper exp. limit, %
57
Lower exp. limit, %
4
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Water runoff can cause environmental damage. Dike and collect water used to fight fire. Use water spray to keep fire-exposed containers cool. Wear appropriate protective clothing to prevent contact with skin and eyes. Wear a self-contained breathing apparatus (SCBA) to prevent contact with thermal decomposition products. Extremely flammable liquid. Vapor may cause flash fire. Forms peroxides of unknown stability. Containers may explode in the heat of a fire. Will be easily ignited by heat, sparks or flame. Extinguishing media: For small fires, use dry chemical, carbon dioxide, water spray or alcohol-resistant foam. For large fires, use water spray, fog, or alcohol-resistant foam. Use water spray to cool fire-exposed containers.
Fire potential
Very flammable, combustion imminent.
Hazards
Vapors are heavier than air and may travel a considerable distance to a source of ignition and flash back.
Combustion products
Produces irritating vapor when heated Vapors are heavier than air and may travel a considerable distance to a source of ignition and flash back.
Health
2
 
Flammability
4
 
 
Reactivity
2
 

Health.
Exposure limit(s)
OSHA PEL: TWA 200 ppm (360 mg/m3) NIOSH REL: Ca See Appendix A See Appendix C (Aldehydes) NIOSH IDLH: Potential occupational carcinogen 2000 ppm
Carcinogin
G-A3, I-2B, N-2, CP65
Poison_Class
4
Exposure effects
Prolonged or repeated skin contact may cause dermatitis. Prolonged or repeated eye contact may cause conjunctivitis. May cause cancer according to animal studies. May cause reproductive and fetal effects. Laboratory experiments have resulted in mutagenic effects. Prolonged skin contact may cause erythema and burns.
   Ingestion
Harmful if swallowed. May cause gastrointestinal irritation with nausea, vomiting and diarrhea. May cause central nervous system depression.
   Inhalation
Causes respiratory tract irritation. May cause narcotic effects in high concentration. Exposure produces central nervous system depression. Vapors may cause dizziness or suffocation. Can produce delayed pulmonary edema. Inhalation of large amounts may cause respiratory stimulation, followed by respiratory depression, convulsions and possible death due to respiratory paralysis. May cause respiratory sensitization.
   Skin
May cause skin sensitization, an allergic reaction, which becomes evident upon re-exposure to this material. Causes skin irritation and possible burns.
   Eyes
Lachrymator. Causes severe eye irritation and possible burns.

First aid
 
   Ingestion
Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
   Inhalation
Get medical aid immediately. Remove from exposure to fresh air immediately. If breathing is difficult, give oxygen. DO NOT use mouth-to-mouth respiration. If breathing has ceased apply artificial respiration using oxygen and a suitable mechanical device such as a bag and a mask.
   Skin
Get medical aid immediately. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Discard contaminated clothing in a manner which limits further exposure. Destroy contaminated shoes.
   Eyes
Get medical aid immediately. Do NOT allow victim to rub or keep eyes closed. Extensive irrigation is required (at least 30 minutes).

Transport.
UN number
1089
Response guide
Hazard class
3.1
Packing Group
I
 
USCG CHRIS Code
AAD
 
HS Code
2912 12 00
 
Std. Transport #
4907210
 
IMO Pollution Category
C
IMO Gas Code
B