Description | Propionaldehyde is a volatile liquid substance which consists of one carbonyl group and its characteristic functional group. The main functional group is an aldehyde which classifies propionaldehyde in the carbonyls. The main trunk of this substance is a short aliphatic chain. The carbonyl group determines, to a large extent, its chemical properties and most importantly its nucleophilic property. Propionaldehyde is readily oxidized if in contact to oxygen and should therefore be stored under inert gases. |
Chemical Properties | Propionaldehyde has a characteristic sharp and pungent odor similar to acetaldehyde.It undergoes reactions typical for the low molecular weight aldehydes, which, because of the terminal carbonyl group, are very reactive. Contamination or the exposure to elevated temperatures may induce a hazardous polymerization.
Propionaldehyde is a colorless, flammable liquid with a suffocating fruity odor. It is used as Intermediate for the chemical industry, for example for the manufacture of pharmaceuticals, pesticides, perfumes and plastics. |
Occurrence | Reported found in apple aroma and in the essential oils of camphor, Rosa centifolia, clary sage, Pinus excelsa and Pinus silverstris. Also reported found in over 100 natural products including apple, banana, sweet cherry, sour cherry, black currant grapes, melon, pineapple, strawberry, cabbage, carrot, celery, cucumber, garlic, onion, leek, potato, peas, rutabaga, tomato, Scotch spearmint oil, vinegar, bread and bread preferment, blue cheeses, cheddar cheese, Swiss cheese, butter, milk, cream, boiled egg, caviar, fatty fish, cooked turkey, beef, pork and chicken, beer, rum, cognac, whiskies, grape wines, coffee, cocoa, tea, roasted filberts and peanuts, peanut oil, potato chips, pecans, oats, honey, soybeans, Arctic bramble, beans, Bantu beer, plum brandy, cauliflower, Brussels sprouts, rice, prickly pear, peated malt, clary sage, truffle, krill, oysters, loganberry, Chinese quince and maté. |
Uses | Manufacture of propionic acid, polyvinyl, and other plastics; synthesis of rubber chemicals; disin- fectant; preservative. |
Uses | Propionaldehyde is produced by the oxo reaction of ethylene with carbon monoxide and hydrogen. n-Propyl alcohol is produced by hydrogenation of propionaldehyde, and propionic acid is made by oxidation of propionaldehyde. n-Propyl alcohol is used as solvent in printing inks and as an intermediate in the preparation of agricultural chemicals. Propionic acid is used as a grain preservative as, for example, in preventing spoilage of wet corn used as animal feed. The use of propionic acid as a grain preservative is an alterna tive to drying by heating, which consumes fuel, and is considered mostly when fuel is expensive. |
Uses | Propionaldehyde is used in the productionof propionic acid, propionic anhydride, andmany other compounds. It is formed in theoxidative deterioration of corn products, suchas corn chips. It occurs in automobile exhaustgases. |
Definition | ChEBI: An aldehyde that consists of ethane bearing a formyl substituent. The parent of the class of propanals. |
Preparation | By oxidation of propyl alcohol, or by dry distillation of barium propionate with calcium formate. |
Preparation | Propionaldehyde is prepared in the usual way by the oxidation of n-propyl alcohol. It can also be prepared by dehydrogenating the alcohol by passing the vapors over a heated copper or brass catalyst. This avoids the danger of further oxidation to propionic acid. The reactions of propionaldehyde are practically like those of acetaldehyde. It must be remembered that only the two alpha hydrogen atoms are active in replacement and condensation reactions. |
General Description | A clear colorless liquid with an overpowering fruity-like odor. Less dense than water. Flash point 15°F. Vapors are heavier than air. |
Air & Water Reactions | Highly flammable. Soluble in water. |
Reactivity Profile | Propionaldehyde may form explosive peroxides. Reacts vigorously with oxidizing agents. Explosive in the form of vapor when exposed to heat or flame [Lewis]. Incompatible with strong bases and strong reducing agents. Vigorous polymerization reaction with methyl methacrylate. Polymerization may also occur in the presence of acids or caustics . |
Hazard | Flammable, dangerous fire risk, explosive limits in air 3.0–16%. Upper respiratory tract irri- tant. |
Health Hazard | Propionaldehyde is a mild irritant to humanskin and eyes. The irritation effect from40 mg was severe in rabbits’ eyes. The toxicityof this compound observed in test animalswas low. Subcutaneous administration in ratsexhibited the symptoms of general anestheticeffect, convulsion, and seizure. Inhalationtoxicity was determined to be low. A concentrationof 8000 ppm (19,000 mg/m3) inair was lethal to rats. LD50 value, oral (rats): 1400 mg/kg LD50 subcutaneous (rats): 820 mg/kg. |
Fire Hazard | Behavior in Fire: Vapor is heavier than air and may travel considerable distance to a source of ignition and flash back. |