CHEMICAL DATA NOTEBOOK SERIES #91: BUTYL ALCOHOL
HAZARDOUS MATERIALS
Butyl alcohol is a flammable, toxic, irritating, slightly corrosive, clear, colorless liquid with a strong alcoholic odor. It is used as a solvent and as a raw material in the manufacture of film, glue, perfume, pharmaceuticals, plastics, shellac, and many other chemicals. Butyl alcohol is commonly known as butanol. Properties, identification, and hazards will be given for the four isomers.
PROPERTIES
Butyl alcohol is one of four butanol isomers. An isomer is a chemical compound that has the same molecular formula as—but a different structural formula than—another chemical compound. The different structural formula gives each of the isomers a slightly different set of properties. Butyl alcohol is more commonly known as normal butyl alcohol, usually written n-butyl alcohol Its correct chemical name is n-butanol, and the isomers are sec-butyl alcohol or sec-butanol (“sec” is short for secondary), tertbutyl alcohol or tert-butanol (“tert” is short for tertiary), and isobutyl alcohol or isobutanol. The properties of these four isomers are shown in the table below. Note that the properties of specific gravity and vapor density relating to molecular weight (which, obviously, is the same for all the isomers) are identical. However, those properties related to the shape of the molecule—namely flash point, flammable range, ignition temperature, boiling point, and freezing point—change as the structures of the different isomers change. As you can see, some of the significant differences in properties are crucial to emergency responders. The implication here is that one must not settle for information that the product involved in the incident is merely butyl alcohol. To avoid deadly surprises, it is vitally important to know which isomer is involved. It is also important to remember that these four isomers are four different chemicals.
IDENTIFICATION
Students of the chemistry of hazardous materials often complain loudly that they are forced to learn different names for the same chemicals. The reason for this is that chemists over the years sought to develop a system for naming chemicals that would make it possible to identify the chemical in question. In trying to develop such a system, however, they created a great deal of confusion because makers, buyers, and users of the chemicals insisted on calling them by whatever name they preferred. Therefore, some chemicals in the stream of commerce (and therefore candidates for accidental releases) may have from two to 10 chemical names, plus an unknown number of trade names. It can be, and most often is, very confusing. Unfortunately, there is no relief in sight. People tend to identify a chemical by the first name they learned, and they also tend to pass that particular name on. Butyl alcohol, or more accurately, normal butyl alcohol, has been known as n-butanol for many, many years. However, very few emergency responders outside of industry refer to it as such. The isomers have even more complicated proper chemical names. The molecular formula for normal butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and isobutyl alcohol is C4H10O or C4H9OH.
HAZARDS
Flammability is the principal hazard of all the butyl alcohol isomers. The flash points (52°F for the tertiary, 75°F for the secondary, 82°F for the isobutyl, and 84°F for the normal) mean that at room temperature, tert-butyl alcohol evaporates at such a rate that it produces vapors sufficient to form an ignitable mixture with the air near the surface of the liquid. Secbutyl alcohol’s flash point is so close to the room temperature of laboratory or manufacturing facilities, especially on warm days, that this isomer also produces vapors sufficient to be above the lower flammable (explosive) limit.
A hidden danger of both normal butyl alcohol and isobutyl alcohol is that the flash points are a little higher than those lor the other two isomers. Users of these materials might believe that since the flash points are in the 80°F+ range, they artsafe to use. Remember, however, that these two isomers are also flammable liquids (by definition ) and that all of the liquid must not be raised to the flash point to be a hazard. If any part of the process in which normal butyl alcohol and isobutyl alcohol are used can input energy to the liquids and the surface of these liquids reaches 82°F (or 84°F), this would be sufficient to create a serious hazard. Many times these materials are used around warm (or hot) equipment, and the heat radiated from such equipment may be sufficient to raise the temperature of some or all of the liquid to the flash point.
The terms flammable and combustible liquids really are dangerous misnomers, since liquids do not burn. What burns are the vapors released from those liquids as they evaporate. The term flammable liquid is given to those liquids that have flash points below 100°F, while combustible liquids are those liquids with flash points at 100°F and higher.
These names also lead people (especially firefighters) to believe that when the vapors are ignited in air, they simply burn. Nothing could be further from the truth. An explosion inevitably happens when vapors of flammable or combustible liquids (or flammable gases, for that matter) are within their flammable ranges. And, if there is no ignition source near the release of the liquid, the vapors of those liquids will accumulate and flow (vapors are fluids) downhill or along low spots in the terrain (if not disturbed by wind or other turbulence) until they find an ignition source. The resultant explosion then will “flash back” along the trail of vapors to the original source. Anyone caught in this path will have a very unpleasant experience!
If the vapors are more or less contained in a particular area due to the configuration of the terrain or other factors, the resulting explosion could be devastating. Remember, the first phenomenon that occurs on ignition of any amount of vapors that burn is an explosion, not a fire. The fire follows the explosion, if anything is left to burn.
All the isomers of butyl alcohol are moderately toxic. Normal butyl alcohol’s TLV-TWA (threshold limit value-time weighted average) has a ceiling limit of 50 ppm (parts per million of air), while the other three isomers have a TLV-TWA of 100 ppm. Tert-butyl alcohol’s TLV-TWA is listed as being proposed for a change in the future.
Ingesting any of the isomers will cause one or more of the following symptoms: diarrhea, dizziness, headache, narcosis, nausea, and vomiting. Ingesting large quantities could cause death.
Eye contact with the liquid or continued contact with high concentrations of vapors could cause severe irritation.
Inhaling large quantities will irritate the nose and throat, and continued inhalation will cause many of the symptoms of ingestion in addition to blurred vision and central nervous system (CNS) depression. Prolonged CNS depression could cause death.
Repeated or prolonged contact of any of the isomers with the skin can cause severe irritation by defatting action (the solvent action of the alcohol).
All of the butyl alcohol isomers are considered stable chemicals, but they might react violently if they contact strong mineral acids or strong oxidizers. At high temperatures, there may be a reaction with aluminum. The butyl alcohol isomers also will corrode some coatings, plastics, and rubber compounds.
NONFIRE RELEASE
None of the butyl alcohol isomers are considered very hazardous or dangerous,so some incident commanders might not choose to activate the community’s emergency response plan. This could be a serious mistake, especially if the release is a large one. Some mild harm to the environment could be caused by the liquid’s percolation into the soil, and any liquid that enters a waterway could damage all aquatic life. It never hurts to have environmental experts present to offer advice on how to avoid damage to the environment caused by mitigation techniques. In addition, all the other activated resources can stand by in case the situation gets out of control. Do not let ego stand in the way of safeguarding your community.
Treat releases of any of the butyl alcohol isomers as releases of any other flammable liquids. Approach from upwind and uphill, eliminate all ignition sources, and restrict all nonessential personnel from entering the danger zone.
Just because the butyl alcohol isomers are not extremely hazardous chemicals doesn’t mean that you should not take all standard precautions. The liquid must not >enter any sewer system or waterway. If possible, contain the release by damming or diking with soil or other material that can be pushed up around the spill.
The major danger will be the explosive vapors being generated. The high vapor density of all the isomers (since all the butyl alcohol isomers have the same chemical formula, they all have the same vapor density of 2.5) means that the vapors will flow along low spots in the terrain and stay together for a considerable distance.
Since all the butyl alcohol isomers are soluble in water, their vapors can be dissolved out of the air by the downwind application of water spray. Of course, the runoff from this operation must be contained, since this water will contain some concentration of butyl alcohol.
Another mitigation technique would be to slow the production of vapors, or prevent them from accumulating, by covering the spill with alcohol-resistant firefighting foam. The foam may break down over time and may have to be replenished. The use of foam presupposes the ability to contain the additional volume of liquid created.
The butyl alcohol isomers also may be diluted by adding water to the released pool, assuming the liquid can continue to be contained. The dilution technique raises the flash point of the original material by spreading the molecules of the ^product out further. If enough water can be added (and contained), the flash point could be raised to higher than 100°F, making the remaining solution much safer. The entire solution could be salvaged and the butyl alcohol isomers recovered kfrom the solution.
Since any vapors generated and released from the pool of spilled product will stay together, they may accumulate in low spots, causing an explosion and toxic hazard for anyone in the area.
Any entry of butyl alcohol into a sewer system could cause the system to fill with explosive vapors. Warn all sewage treatment facilities immediately. Within the sewer, the concentration of vapors probably would be above the upper flammable limit, but at any opening in the system the vapors are sure to be within the flammable range. Any ignition source near such an opening could cause a citywide explosion.
If any of the butyl alcohol isomers enter a waterway, the alcohol will dissolve in the water. The danger to aquatic life depends on the size and type of waterway and the amount of product entering it. Alert all downstream users of the water as soon as entry occurs.
IDENTIFICATION NUMBERS AND RATINGS
CAS
(Chemical Abstract Services) normal butyl alcohol: 71-36-3 sec-butyl alcohol: 78-92-2
tert-butyl alcohol: 75-65-0 isobutyl alcohol: 78-83-1
STCC (Standard Transportation Commodity Code)
normal butyl alcohol: 4909117 sec-butyl alcohol: 4909129
tert-butyl alcohol: 4909230 Isobutyl alcohol: 4909131
RTECS (Registry of Toxic Effects of Chemical Substances)
normal butyl alcohol: EO 1400000 sec-butyl alcohol: E01750000
tert-butyl alcohol: EO 1925000 isobutyl alcohol: NP9625000
UN/NA (United Nations/North America)
normal butyl alcohol: 1120 sec-butyl alcohol: 1120 or 1121
tert-butyl alcohol: 1120 or 1122 isobutyl alcohol: 1212
CHRIS (Chemical Hazard Response Information System)
normal butyl alcohol: BAN sec-butyl alcohol: BAS
tert-butyl alcohol: BAT isobutyl alcohol: 1AI.
RCRA (Resource Conservation and Recovery Act) normal butyl alcohol: U031 (waste number) isobutyl alcohol: U140 (waste number)
DOT (U.S. Department of Transportation)
normal butyl alcohol: Class 3, flammable liquid sec-butyl alcohol: Class 3, flammable liquid
tert-butyl alcohol: Class 3, flammable liquid isobutyl alcohol: Class 3, flammable liquid
NFPA 704 Rating
normal butyl alcohol: 1-3-0 sec-butyl alcohol: 1-3-0
tert-butyl alcohol: 1-3-0 isobutyl alcohol: 1-3-0
IMO (International Maritime Organization)
normal butyl alcohol: 3.3, flammable liquid sec-butyl alcohol: 3.3, flammable liquid
tert-butyl alcohol: 3.3, flammable liquid isobutyl alcohol: 3-3, flammable liquid
SYNONYMS
normal butyl alcohol
butan-1 -ol
butyl hydroxide
butyl alcohol
butyric alcohol
n-butyl alcohol
CCS 203
1-butanol
1-hydroxybutane
methylolpropane
n-butanol
n-propylcarbinol
propylcarbinol
propylmethanol
normal butanol
sec-buty l alcohol
2-butanol
butan-2-ol
2-butyl alcohol
butylene hydrate
CCS 301
ethyimethylcarbinol
2-hydroxybutane
methylethylcarbinol
S.B.A.
sec-butanol
secondary’ butanol
tert-butyl alcohol
1,1 -dimethylethanol
2-methyl-2-propanol
NCI-c55367
tert-butanol
tertiary butanol
tert-butyl hydroxide
trimethylcarbinol
isobutyl alcohol
fermentation butyl alcohol
1 -hydroxymethylpropane
p isobutanol
isopropylcarbinol
2-methyl propanol
2-methylpropan-1 -ol
2-methyl-1 -propanol
2-methylpropyl alcohol
Contaminated water can be decontaminated by aeration techniques, if it is possible to isolate or divert such water. This should be carried out by certified experts. Firefighters never should become involved in the salvage or cleanup of anyreleased material, hazardous or not. The environmental authorities must decide when the water is safe tor use again.
Salvage of contained product is relatively safe and easy, but it still should be carried out by properly educated, trained, and equipped professionals. The shipper, seller, or buyer of the product should carry out this work or arrange tor it to be done (and pay for it). In fact, all costs, including the cost of the fire department’s response, should be paid for by the partyresponsible for the incident. If ail fire departments made those responsible for the spills pay for their response and the eventual cleanup (and any damage to the environment), there would be an absolutely phenomenal drop in hazardousmaterials incidents.
FIRE SCENARIO
Fires caused by the release of butyl alcohol isomers may be fought with alcohol foam, carbon dioxide, dry chemical, or water spray. The choice of fire extinguishing agent depends on the findings of the incident commander’s size-up. As in the case of any fire involving a hazardous material, contain any water runoff.
Dilution with water may be used as a mitigation technique if the resulting increased volume can be contained. Applying water directly to a pool or container of burning butyl alcohol isomers (as opposed to applying water spray to extinguish the llames) not only will cool the unburned product but will spread out the alcohol’s molecules, slowing the entry’ of fresh fuel into the burning zone. Manufacturers of butyl alcohol will be glad to share this or any other firefighting technique with your fire department. Just ask!
As you would for all flammable liquid fires, cool containers of butyl alcohol isomers by applying water if you can do it safely! Your training has provided you with approach techniques. Unmanned appliances placed as far away as possible should apply all cooling water. The probability of a boiling-liquid, expanding-vapor explosion (BLEVE) is not as high as it would be with an easily liquefiable flammable gas, but take no chances. Remember O’Brien’s law: Murphy was an optimist!
PROTECTIVE CLOTHING AND EQUIPMENT
Choose protective clothing and equipment that prevents the liquid or vapor from contacting the eyes, skin, or respiratory system. Use splashproof chemical goggles and a face shield to protect the eyes, and use positive-pressure, self-contained breathing apparatus. Rubber boots, gloves, and aprons and other impervious clothing will offer protection. If total encapsulating suits are worn, know that manufacturers claim materials such as butyl rubber, chlorinated polyethylene, neoprene, nitrile-butadiene rubber (NBR), nitrile rubber, polyethylene, polyurethane (PUR), polyvinyl chloride (PVC), styrene-butadiene, and Viton® may offer protection. Another reference suggests that only butyl rubber. Teflon®, and polyethylene/ethylene vinyl alcohol offer protection for normal butyl alcohol and isobutyl alcohol. Only butyl rubber and polyethylene/ethylene vinyl alcohol offer protection for the secand tertisomers. This raises questions as to which materials offer what protection, but it may not be a major issue, since contact with butyl alcohol is not as hazardous as contact with many other substances. For safety, however, ask the manufacturers of butyl alcohol for their recommendations.
FIRST AID
Inhalation. Remove the victim to fresh ” air. If the victim has stopped breathing or i if breathing has become difficult, administer artificial respiration (mouth-to-mouth resuscitation may expose the provider of first aid to the material in the victim’s mouth or vomit). Provide medical atten-⅜ tion immediately.
Ingestion. If the victim is conscious and ‘ less than two hours has passed since ingestion, give the victim two glasses of water and induce vomiting. At least one source suggests that vomiting be induced only if immediate medical attention is not ’ available. Never try to force an unconscious person to drink anything or vomit. Call for immediate medical attention while making sure the victim is warm and comfortable.
Skin contact. Remove all contaminated, clothing and wash all affected body areas with large amounts of water. Provide medical attention if skin irritation persists after washing.
Eye contact. Immediately flush the eyes with large amounts of water for 15 minutes. occasionally lifting the eyelids. Provide immediate medical attention.
