Propanol, technically known as 1-Propanol, is a primary alcohol with the formula CH3CH2CH2OH.
This colorless liquid is also known as propan-1-ol, 1-propyl alcohol, n-propyl alcohol, and n-propanol.
It is an isomer of isopropanol. It is formed naturally in small amounts during many fermentation
processes and used as a solvent in the pharmaceutical industry mainly for resins and cellulose esters.
Chemical properties 1-Propanol shows the normal reactions of a
primary alcohol. Thus it can be converted to alkyl halides; for example red phosphorus
and iodine produce n-propyl iodide in 80% yield, while PCl3 with catalytic ZnCl2 gives
1-chloropropane. Reaction with acetic acid in the presence of an H2SO4 catalyst under
Fischer esterification conditions gives propyl acetate, while refluxing propanol overnight
with formic acid alone can produce propyl formate in 65% yield. Oxidation of 1-propanol
with Na2Cr2O7 and H2SO4 gives only a 36% yield of propionaldehyde, and therefore for this
type of reaction higher yielding methods using PCC or the Swern oxidation are recommended.
Oxidation with chromic acid yields propionic acid.
Preparation 1-Propanol is manufactured by catalytic hydrogenation
of propionaldehyde. The propionaldehyde is itself produced via the oxo process, by hydroformylation
of ethylene using carbon monoxide and hydrogen in the presence of a catalyst such as cobalt
octacarbonyl or a rhodium complex. H2C=CH2 + CO + H2 → CH3CH2CH=O
CH3CH2CH=O + H2 → CH3CH2CH2OH A traditional laboratory preparation of 1-propanol
involves treating n-propyl iodide with moist Ag2O.
1-Propanol was discovered in 1853 by Chancel, who obtained it by fractional distillation
of fusel oil. Indeed 1-propanol is a major constituent of fusel oil, a by-product formed
from certain amino acids when potatoes or grains are fermented to produce ethanol. This
process is no longer a significant source of 1-propanol.
Safety 1-Propanol is thought to be similar to ethanol
in its effects on human body, but 2-4 times more potent. Oral LD50 in rats is 1870 mg/kg.
It is metabolized into propionic acid. Effects include alcoholic intoxication and high anion
gap metabolic acidosis. As of 2011, only one case of lethal 1-propanol poisoning was reported.
Inhalation Although this method is rare, it does indeed
exist. Propanol might be much more convenient than ethanol for inhalation because of its
potency with nebulizers. Propanol as fuel
1-propanol has high octane numbers and it is suitable to engine fuel usage. However,
production of propanol has been too expensive to be a common fuel. The Research octane number
of propanol is 118 and Anti-Knock Index is 108.
References
Further reading Furniss, B. S.; Hannaford, A. J.; Smith, P.
W. G.; Tatchell, A. R., Vogel's Textbook of Practical Organic Chemistry, Harlow: Longman,
ISBN 0-582-46236-3 Lide, David R., ed.. CRC Handbook of Chemistry
and Physics, 87th Edition. TF-CRC. ISBN 0-8493-0487-3. Maryadele J. O'Neil, ed.. The Merck Index:
An Encyclopedia of Chemicals, Drugs, and Biologicals. Merck. ISBN 0-911910-00-X.
Perkin, W. H.; Kipping, F. S. Organic Chemistry. London: W. & R. Chambers. ISBN 0-08-022354-0.
External links International Chemical Safety Card 0553
NIOSH Pocket Guide to Chemical Hazards