CHLOROSULFONIC ACID
HAZARDOUS MATERIALS
CHEMICAL DATA NOTEBOOK SERIES #55
Chlorosulfonic acid is a corrosive, oxidizing, water-reactive, toxic, reactive, irritating, colorless-to-light-yellow, slightly cloudy, fuming liquid. It has a sharp, pungent, penetrating odor and is an extremely dangerous material. It is used in the manufacture of catalysts, chemical blowing agents, detergents, dyes, pesticides, pharmaceuticals, pigments, plastics resins, plasticizers, saccharin, surfactants, tanning agents, and many other chemicals and chemical intermediates.
PROPERTIES
Chlorosulfonic acid will not burn, but since it is an oxidizing agent it will support the combustion of any substance that will burn. In fact, it is such a powerful oxidizer that it will react explosively with many substances, some of which are mentioned later. It has a specific gravity of 1.766 and a molecular weight of 116.5. It boils at 306°F, freezes at – 112°F, and reacts violently with water. Its chemical formula may be written any of the following ways: HCISO3, ClSO>OH, and HOSCbCl.
HAZARDS
Chlorosulfonic acid is a very strong inorganic acid and is highly corrosive to human tissue, most metals, and many rubbers and plastics. Its corrosive action with metals may release hydrogen, a highly flammable gas. It also will attack all living tissue and many minerals. By reacting with the calcium carbonate that makes up the aggregate stone in most asphalt paving materials it wall destroy asphalt streets. It will attack concrete byreacting with the calcium compounds and other minerals that make up the concrete mix and added stone.
Chlorosulfonic acid is a very powerful oxidizing agent. It should never be stored near anything that will burn, and that includes all organic material. Fuel can be defined as “anything that will burn.” Since all organic materials will burn, they are all fuels. Fuels refer not only to organic materials used in automobiles, heating, and cooking but also to wood and wood products, cardboard, and paper and paper products. Hydrocarbon derivatives such as alcohols, ethers, aldehydes, ketones, esters, organic acids, peroxides, and amines are also fuels, as are all other hydrocarbon compounds and mixtures.
The combination of water-reactivity and oxidizing power in concentrated chlorosulfonic acid actually will produce a fire in certain combustibles in the same manner that concentrated sulfuric acid will. Its reaction with moisture in wood, cardboard, or paper and related products will generate enough heat to ignite the material.
Chlorosulfonic acid will react violently with water. On contact it will break down into sulfuric acid and hydrochloric acid, generating large amounts of acidic white fumes (consisting of hydrogen chloride and sulfur trioxide) and tremendous amounts of heat. Fuming results from chlorosulfonic acid reacting with water in moist air. This generates the white fumes consisting of hydrogen chloride and sulfur trioxide dissolving in the moisture. The heat generated by this reaction is often sufficient to ignite any ordinary combustible nearby.
A dangerous reaction will occur if chlorosulfonic acid is released from its container and comes in contact with any of a great number of chemicals. Contact with phosphorus will produce an explosion, while contact with diphenyl ether, silver nitrate, or sulfuric acid will cause a very violent reaction. Other violent (or dangerous) reactions will occur when chlorosulfonic acid contacts all hydrocarbon derivatives; powdered metals; bases such as sodium, potassium, and ammonium hydroxides; inorganic acids such as hydrochloric, hydrofluoric, and nitric acids; organic acids such as acetic acid; oxidizers such as chlorates, nitrates, and hydrogen peroxide; explosive materials such as fulminates and picrates; monomers such as acrolein, acrylic acid, acrylonitrile, ethyl acrylate, isoprene, styrene, vinyl acetate, and vinylidene chloride; and many other chemicals.
Because chlorosulfonic acid reacts with so many chemicals, a train derailment containing one or more tank cars filled with it can be extremely dangerous. Such a spill will generate hydrogen by the corrosive action of the acid on steel, heat, hydrochloric acid, and sulfuric acid as it contacts water. Violent reactions are possible as it contacts any one of hundreds of common chemicals transported by rail.
SYNONYMS
chlorosulfuric acid
chlorsulfonic acid
monchlorosulfiiric acid
sulfonic acid
monochloride
sulfuric chlorohydrin
Contact with the eyes will cause severe burns and will almost always cause blindness. The same damage may occur from exposure to chlorosulfonic acid vapors and the other acidic vapors produced when chlorosulfonic acid contacts moisture.
If concentrated chlorosulfonic acid contacts the skin, it will cause severe burns and, in most cases, total destruction of the contacted skin. Death will occur if enough surface area of the body has been affected.
Inhaling chlorosulfonic acid vapors or the acid vapors generated by its fuming action may cause severe damage to the upper and lower respirator)’ system. Damage to the lungs may be delayed but may be irreversible and severe enough to cause death.
Ingestion of concentrated chlorosulfonic acid will cause severe burns of the mouth, esophagus, and stomach. Irreversible damage may be done to these organs, and a painful death will follow.
In lower concentrations, the damage may be less severe in each of the situations mentioned, but the acid still has the potential to be life-threatening. Protect the body and respiratory system from any contact with chlorosulfonic acid and/or its vapors.
NONFIRE RELEASES
In the event of any release of a material as hazardous as chlorosulfonic acid, keep all unnecessary personnel away from the immediate area of the spill (the hot zone) throughout the incident. Because of its chemical properties and its water-reactivity, chlorosulfonic acid will he fuming, producing very noxious and dangerous fumes of sulfuric and hydrochloric acids. Anyone contacting these fumes without respiratory protection will he at great risk. Therefore, evacuation of all individuals in the immediate area must be a top priority. Evacuation should he underway by the time the environmental authorities are alerted to the release.
Chlorosulfonic acid immediately will begin to react with the moisture in the air and soil if the acid has reached unpaved ground. It will begin oxidizing any organic material in the soil, and the heat released from this water contact may ignite any ordinary combustible nearby.
If the spill occurs on paved ground, the acid will attack the pavement itself. This reaction with the aggregate (stones) in asphalt pavement, the aggregate in concrete pavement, or the concrete itself will slightly neutralize the acid by using part of it up. However, this neutralization will not effectively reduce the dangerous properties of the acid unless the spill is approximately one quart or less.
Assuming the spill is large, the chlorosulfonic acid must be kept from spreading. Employ the same techniques used to contain other liquids, but keep in mind the increased hazard of dealing with chlorosulfonic acid. A containment pond may be created by pushing dry soil or dry sand into dikes around the spill. Take extreme care to avoid any contact with the acid, and ensure that any tools, equipment, and machinery used are compatible with the product —that is, that they are made of a material that can resist the strong corrosive action of the acid.
If machinery and operators arc available, a containment pit may be dug. Trenches may be dug to lead the liquid chlorosulfonic acid into the pit. Consult with environmental authorities to determine the method that will provide the least amount of soil contamination. These containment techniques are not recommended for firefighters but rather for professionals who have been properly trained, educated, and equipped to do the job. It is imperative that anyone attempting to contain chlorosulfonic acid be prepared for a sudden increase in fuming as the acid contacts new sources of moisture.
IDENTIFICATION NUMBERS AND RATINGS
CAS
(Chemical Abstract Services)
7790-94-5
STCC
(Standard Transportation Commodity Code)
4930204
RTECS
(Registry of Toxic Effects of Chemical Substances)
FX5730000
UN/NA
(United Nations/North America)
1754
CHRIS
(Chemical Hazard Response Information System) CSA DOT
(U.S. Department of Transportation)
Corrosive NFPA 704 Rating
3-0-2-OXY
IMO
(International Maritime Organization)
Corrosive, 8
If the containment pit is used, a cover made of a compatible material may be placed over the pit to slowdown or help contain fumes and protect the product from rain or contact with another incompatible material. An open pit will produce less fumes than a pond because the pond exposes a larger surface area of the chlorosulfonic acid to the atmosphere. A material such as white mineral oil, perlite, or clay applied to the surface may reduce the generation of fumes. Covering the chlorosulfonic acid with a foam is not advisable, since foams are water-based and will produce a reaction. Consult the manufacturer of the acid for help in addition to the shipper and consignee. The mitigation technique of dilution is not advisable because the addition of water w ill begin a violent reaction.
Neutralization may be effective if the neutralization agents are available and they can be applied safely. Acceptable neutralizing agents are soda ash (sodium carbonate) and ground limestone (calcium carbonate). Perform a sample test first by removing a small amount of the acid to a safe place and then carefully adding the selected neutralizing agent. Note any adverse reactions and estimate the amount of material required to neutralize the entire spill.
Chlorosulfonic acid may react with any metal in the area of the spill, producing explosive hydrogen gas. Any metal contacted by the fumes also will be damaged.
The acid vapors generated by fuming chlorosulfonic acid are heavier than air. Therefore, they will “hang together” and flow downhill and/or move with a gently blow ing breeze. A strong wind will break up the fumes and disperse them over a wider area more quickly, reducing the hazard far downwind. In the absence of a strong wind, evacuate downwind for an area at least one mile long and one-half mile wide or perhaps larger, depending on the size of the spill and weather conditions. Applying a high-pressure spray or fog will help disperse vapors in the air, but take care to keep the water from contacting the spill itself. The runoff water created by the spraying action will be contaminated with dissolved acid gases and be acidic itself.
Once the chlorosulfonic acid is contained, the manufacturer, the shipper, the consignee, or some professional firm experienced in the transfer of hazardous materials should begin removal of the material. Once the bulk of the acid is removed, any remaining acid may be neutralized by adding soda ash or ground limestone. Any liquid remaining after this procedure may be absorbed by the addition of cement powder, clay, or fly ash. If the acid spill is small and neutralization is not a viable option, absorption of the untreated acid with these materials may be attempted. Perform a test first with a small amount of the acid. Once used, the absorbents may become as dangerous as the original acid, since the acid is still present in its original chemical composition. In any case, the environmental authorities will decide how much contaminated soil must be removed and disposed of in accordance with federal, state, and local regulations.
Attempt to keep chlorosulfonic acid from entering sewers and waterways. Entry into sewers is particularly dangerous since sewers are usually full of organic material and chlorosulfonic acid is a powerful oxidizer —all that is needed for an explosion to occur is an ignition source. The heat from the exothermic reaction may be enough to provide ignition. In addition, tremendous amounts of acid vapors will be formed as the acid contacts water in the sewer. The results are a possible explosion and/or the spreading of acid gases throughout a city through the sewer system.
If chlorosulfonic acid does enter the sewer system, notify the sewage treatment plant immediately. Also, protect the people who might be exposed to acid fumes coming from every manhole cover or catch basin.
If chlorosulfonic acid enters a waterway, notify all downstream users of the water immediately. Any intake of acidic water into an industrial or other application may damage equipment and could be extremely hazardous to humans. If the waterway is a stream or small river, use a containment dike to contain or divert the water to another area until it can be treated.
Sodium carbonate and calcium carbonate may be added to contained water to try to neutralize it. Consult the manufacturer of the chlorosulfonic acid or other expert to determine if this or another neutralization method should be tried. Ask the environmental authorities for suggestions on treating the water. It will be their responsibility to determine when the water is safe, when the waterway is no longer contaminated, and if any damage has occurred to the environment along the waterway or to wildlife in or near it. They also will decide what contaminated soil must be removed and determine if there has been permanent environmental damage.
FIRE SCENARIO
Chlorosulfonic acid will not burn, but its oxidizing nature will support combustion, and its water-reactivity will produce enough heat so that the reaction may be the ignition source. Any time chlorosulfonic acid is released and contacts an organic material or metal, a fire is imminent. Emergency responders should be prepared for a fire whenever the acid is released, keeping in mind the particular hazards associated with this fire situation. Water should not be used to fight a fire where chlorosulfonic acid is present because it will produce severe reactions and large amounts of acid gases. Firefighters probably should not fight this type of fire if protective clothing or equipment is not available.
A railroad accident involving chlorosulfonic acid could occur with no fire, but chances are any leaking acid will react with something, even if it is the steel in the rails. This will liberate hydrogen, which could ignite explosively. In a derailment, the probability of chlorosulfonic acid mixing with some other chemical and producing a violent reaction is very high. Emergency responders must be aware of what could happen.
If the chlorosulfonic acid is not involved in a fire but flames are approaching and threatening containers of the acid, withdraw immediately and apply cooling water to the containers from unmanned appliances located as far away as possible. Rapid rises in pressure caused by radiated or conducted heat can cause the containers to fail catastrophically, resulting in concentrated chlorosulfonic acid being thrown great distances and reacting violently wherever it lands.
GLOSSARY
Blowing agent—a substance that produces a uniform amount of gas when heated to a specific temperature or contacted by a specific chemical.
Dilution—the action of adding water to a water-soluble material, thereby lowering its concentration.
Fuming—the evolution of visible fumes by some highly reactive substance (usually a liquid) on contact with air.
Hydrocarbon derivative—a covalent compound made up of a hydrocarbon “backbone” and a functional group.
Inorganic acid—usually called mineral acids, they are ionic in composition and contain the hydrogen (H + ) ion. They are all strong acids.
Oxidizer—substances that contain oxygen and give it up readily or will otherwise support combustion (also called oxidizing agents). The halogens are oxidizers that contain no oxygen.
Plasticizer—a substance added to a rigid plastic that makes it softer and more pliable.
Surfactant—any substance that reduces interfacial tensions between two liquids or a liquid and a solid.
PROTECTIVE CLOTHING AND EQUIPMENT
Full protective clothing that will protect the emergency responder from all contact with chlorosulfonic acid is an absolute necessity. The onlymaterials recommended by any reference for contact with chlorosulfonic acid are Teflon® and Saranex®. Consult the manufacturers of total encapsulating suits for their recommendations. Use positive-pressure, self-contained breathing apparatus in conjunction with protective clothing.
FIRST AID
If the victim has inhaled chlorosulfonic acid fumes or vapors formed by its reactions, remove him to fresh air and keep him warm and quiet. Administer mouth-to-mouth resuscitation if the victim has difficulty breathing or has stopped breathing altogether (be aware that such action may expose the first-aid giver to the chemical in the victim’s lungs or vomit). Get medical attention immediately.
For eye contact, flush the eyes immediately for at least 15 minutes, occasionally lifting the eyelids. Immediate medical attention is required.
For skin contact, remove contaminated clothing and wash the affected body areas with large amounts of w’ater. Seek immediate medical attention.
For ingestion, if the victim is conscious, make him drink large quantities of water immediately but do not induce vomiting. Never try to make an unconscious person drink anything. Seek immediate medical attention.
