General Description
Colorless liquid with a mild, choking alcohol odor. Less dense than water, soluble in water. Hence floats on water. Produces an irritating vapor.
Reactivity Profile
ISOAMYL ALCOHOL(123-51-3) attacks plastics [Handling Chemicals Safely, 1980. p. 236]. Mixtures with concentrated sulfuric acid and strong hydrogen peroxide may cause explosions. Mixing with hypochlorous acid in water or water/carbon tetrachloride solution can generate isoamyl hypochlorites, which may explode, particularly on exposure to sunlight or heat. Mixing with chlorine would also yield isoamyl hypochlorites [NFPA 491 M, 1991]. Base-catalysed reactions with isocyanates can occur with explosive violence [Wischmeyer,1969].
Air & Water Reactions
Highly flammable. Water soluble.
Hazard
Moderate fire risk. Vapor is toxic and irritant. Explosive limits in air 1.2–9%.
Health Hazard
Very high vapor concentrations irritate eyes and upper respiratory tract. Continued contact with skin may cause irritation.
Potential Exposure
(n-isomer); Suspected reprotoxic hazard,
Primary irritant (w/o allergic reaction), (iso-, primary):
Possible risk of forming tumors, Primary irritant (w/o allergic
reaction), (sec-, active primary-, and other isomers)
Primary irritant (w/o allergic reaction). Used as a solvent in
organic synthesis and synthetic flavoring, pharmaceuticals,
corrosion inhibitors; making plastics and other chemicals;
as a flotation agent. The (n-isomer) is used in preparation
of oil additives, plasticizers, synthetic lubricants, and as a
solvent.
First aid
Skin contact contributes significantly to overall
exposure. If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including
resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical
attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Shipping
UN2811 Pentanols, Hazard Class: 3; Labels: 3-
Flammable liquid. UN1987 Alcohols, n.o.s., Hazard Class:
3; Labels: 3-Flammable liquid.
Incompatibilities
Forms an explosive mixture with air.
Contact with strong oxidizers and hydrogen trisulfide may
cause fire and explosions. Incompatible with strong acids.
Violent reaction with alkaline earth metals forming hydrogen,
a flammable gas.
Description
Isoamyl alcohol has a characteristic pungent odor and repulsive
taste. Industrially prepared by rectification of fusel oil.
Waste Disposal
Dissolve or mix the material
with a combustible solvent and burn in a chemical incinerator
equipped with an afterburner and scrubber. All federal,
state, and local environmental regulations must be
observed.
Physical properties
Clear, colorless liquid with a pungent odor. An odor threshold concentration of 1.7 ppbv was
reported by Nagata and Takeuchi (1990).
Occurrence
Constitutes the major portion of fusel oil; also known as fermentation of amyl alcohol; it has been identified
as an ester among the constituents of Roman chamomile oil; French peppermint, Java citronella, Réunion geranium, tea, Teucrium
chamaedrys, Eucalyptus amigdalina, Achillea ageratum and Artemisia camphorata. It is reported present in the aromas of strawberry and raspberry. It is also reported found in over 230 natural sources including apple, apricot, banana, sweet and sour cherry,
citrus peel oils and juices, berries, guava, grapes, raisin, melon, papaya, peach, pear, pineapple, asparagus, cabbage, kohlrabi,
celery stalk and seed, leek, peas, potato, sauerkraut, tomato, ginger, mint oils, vinegar, mustard, bread, cheeses, butter, milk, fish，meats, cognac, rum, whiskies, cider, sherry, grape wines, tea, filberts, pecans, walnuts, oats, honey, soybean, avocado, Arctic
bramble, olive, passion fruit, rose and Malay apple, mushroom, mango, tamarind, pear brandy, port, cardamom, gin, quince,
radish, sukiyaki, sake, buckwheat, corn oil, sweet corn, laurel, malt, wort, cherimoya, loquat, Bourbon vanilla, shrimp, oysters,
crayfish, mussels and scallops
Characteristics
Amyl alcohols (pentanols) have eight isomers. All are flammable, colorless liquids, except the isomer 2,2- dimethyl-1-propanol, which is a crystalline solid.
Definition
ChEBI: An alkyl alcohol that is butan-1-ol substituted by a methyl group at position 3.
Preparation
3-Methyl-1-butanol and 2-methyl-1-butanol were first isolated from fusel oils, by-products of ethanol fermentation by yeast. These compounds can also be derived from the chlorination of pentane followed by hydrolysis. Another alternative process is the oxo process, a general strategy for the manufacture of C4 and higher alcohols. Both the chlorination process and the oxo process are current commercial processes for the production of 3-methyl-1-butanol and 2-methyl-1-butanol, but the oxo process via the hydroformylation reaction is the more popular. Two main technologies are used for the process. The first was brought on stream by Ruhrchemie in Germany and Exxon in USA in the 1940s and is generally referred to as "high-pressure cobalt catalyst technology." The active catalyst species is cobalt hydrocarbonyl, and a pressure of 200–300 atm is required to maintain the stability of the catalyst. In the early 1960s, Shell commercialized a modern version of the cobalt catalyst process. This technology uses organophosphine ligands, which allows a lower operating pressure of 30–100 atm but at the expense of the catalyst activity. The Shell technology is employed primarily in the production of linear primary alcohols, whereas the high-pressure cobalt technology is frequently used in the production of branched alcohols.
Preparation
Industrially prepared by rectification of fusel oil.
Aroma threshold values
Detection: 250 ppb to 4.1 ppm
Taste threshold values
Taste characteristics at 50 ppm: fusel, fermented, fruity, banana, ethereal and cognac
Flammability and Explosibility
Flammable
Chemical Reactivity
Reactivity with Water: No reaction; Reactivity with Common Materials: No reactions; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
Biochem/physiol Actions
3-Methyl-1-butanol is a pentanol isomer useful in biofuels. It is used as a starting material for the production of isoamyl acetate, a flavoring agent applicable in the food industry. 3-Methyl-1-butanol shows anti-fungal action by inhibiting the hyphal formation and reducing biofilm formation in Candida albicans. It is also used in DNA extraction protocols.
Environmental Fate
Biological. Using the BOD technique to measure biodegradation, the mean 5-d BOD value (mM
BOD/mM isoamyl alcohol) and ThOD were 4.46 and 59.5%, respectively (Vaishnav et al., 1987).
Chemical/Physical. Isoamyl alcohol will not hydrolyze because it has no hydrolyzable
functional group (Kollig, 1993).
Purification Methods
Dry the alcohol by heating with CaO and fractionally distilling, then heating with BaO and redistilling. Alternatively, boil it with concentrated KOH solution, wash it with dilute H3PO4, and dry it with K2CO3, then anhydrous CuSO4, before fractionally distilling it. If very dry alcohol is required, the distillate is refluxed with the appropriate alkyl phthalate or succinate as described for ethanol. It is separated from 2-methyl-1-butanol by fractional distillation, fractional crystallisation and preparative gas chromatography. [Beilstein 1 IV 1677.]
