HuagongsheHuagongshe Chemistry Print Report · For research reference only
Sulfur trioxide
SO3 · SULPHUR TRIOXIDE · SULFURIC ANHYDRIDE · Sulfuric oxide · Schwefeltrioxid · Sulfur oxide (SO3) · Sulfan · SULFAN(R)
Identifiers & Physical Properties
| CAS No. | 12210-38-7 |
|---|---|
| Molecular formula | O3S |
| Average molar mass | 80.07 g/mol |
| Monoisotopic mass | 79.95681486 g/mol |
| SMILES | O=S(=O)=O |
| InChIKey | AKEJUJNQAAGONA-UHFFFAOYSA-N |
| PubChem CID | 24682 |
| ChEBI | CHEBI:29384 |
| EC No. | 231-197-3 |
| DTXSID | DTXSID1029673 |
Chemical & Physical Properties
| XLogP | -0.5 |
|---|---|
| Topological polar surface area | 52.2 |
| Hydrogen bond donors | 0 |
| Hydrogen bond acceptors | 3 |
| Rotatable bonds | 0 |
| Heavy atoms | 4 |
| Formal charge | 0 |
| Complexity | 61.8 |
| Chemical classes | Toxic Gases & Vapors -> Other Toxic Gases & VaporsCarcinogens |
| SpringerMaterials Properties | Schoenflies notation |
| Density | 1.92 at 68 °F Gamma form (liquid) (EPA, 1998) - Denser than waterwill sinkCritical density: 0.630 g/cu cmRelative density (water = 1): 1.91.97 g/mL at 25 °C(lit.) |
| Color/Form | White needlesAsbestos-like needlesPure sulfur trioxide is a colorless liquid that fumes in air at room temperature and pressure. |
| Solubility | Slowly very sol in aqueous, and sol in 100 parts water at room tempSolubility in water: violent reactionreacts with H2Oreacts violently |
| Corrosivity | Absolute dry sulfur trioxide is not corrosive to metals |
| Boiling point | 113 °F at 760 mmHg all forms (EPA, 1998)Sublimes44.8 °C |
| Decomposition | When heated to decomposition ... emits toxic fumes of /sulfur oxides/. |
| Melting point | 144 °F Alpha form90.5 °F Beta form62.2 °F Gamma form (EPA, 1998)62.2 °CExists in three solid modifications: alpha, beta, and gamma. The alpha form seems to be the stable form but the solid transitions are commonly slowa given sample may be a mixture of the various forms and its melting point not constant.Physical form: asbestos-like needlesmelting point: 32.5 °Cvapor pressure: 344 mm Hg at 25 °C /beta-form/17 °C16.8 °C(lit.) |
| Vapor density | 2.76 (EPA, 1998) - Heavier than airwill sink (Relative to Air)2.76 (Air = 1)Relative vapor density (air = 1): 2.82.8 (vs air) |
| Polymerization | Explosive polymerization in case of non-presence of stabilizer and presence of humidity. |
| Vapor pressure | 73 mmHg at 77 °F Alpha form344 mmHg at 77 °F Beta form433 mmHg at 77 °F Gamma form (EPA, 1998)263.0 [mmHg]Vapor pressure: 73 mm Hg at 25 °C /alpha-form/Vapor pressure, kPa at 25 °C: 57.7280 mm Hg ( 25 °C) |
| Storage conditions | Indoors |
| Physical state | colorless liquid |
| Color | white needles |
| Specific heat capacity | Cp(gas): 0.63 J/(g·K), at 25℃ |
| Merck | 13,9069 |
| Henry's law constant | 5.1×10-8 mol/(m3Pa) at 25℃, Hayer et al. (2022) |
| Exposure limits | PC-TWA: 1 mg/m3PC-STEL: 2 mg/m3 |
| Dielectric constant | 3.1(18℃) |
| Stability | Stable. Incompatible with organic materials, finely powdered metals, bases, water, cyanides and a wide variety of other chemicals. Reacts violently with water, oxygen and other chemicals - read a full data sheet before use. |
| InChI | 1S/O3S/c1-4(2)3 |
| InChIKey | AKEJUJNQAAGONA-UHFFFAOYSA-N |
| SMILES | O=S(=O)=O |
| CAS DataBase Reference | 7446-11-9(CAS DataBase Reference) |
| EWG's Food Scores | 1 |
| FDA UNII | HH2O7V4LYD |
| NIST Chemistry Reference | Sulfur trioxide(7446-11-9) |
| EPA Substance Registry System | Sulfur trioxide (7446-11-9) |
| Toxicological Profile|ATSDR | Sulfur trioxide|Toxicological Profile|ATSDR |
| UNSPSC Code | 12352300 |
| GHS pictogram | GHS05 |
| Signal word | Danger |
| GHS hazard statements | H314-H335 |
| GHS precautionary statements | P260-P264-P280-P261-P271-P301+P330+P331-P303+P361+P353-P363-P304+P340-P310-P305+P351+P338-P312-P405-P403+P233-P501 |
| Target organs | Respiratory system |
| Personal protective equipment (PPE) | Faceshields, Gloves, Goggles |
| Hazard symbols | O,T+,C |
| Risk statements (R) | 45-8-14-26-34-37-35 |
| Safety statements (S) | 53-17-26-36/37/39-45-8-25-30 |
| UN transport number | UN 1829 (SULPHUR TRIOXIDE, STABILIZED) |
| Water hazard class (WGK) | 1 |
| RTECS number | WT4830000 |
| TSCA inventory status | TSCA listed |
| Hazard class | 8Eye Dam. 1Skin Corr. 1ASTOT SE 3 |
| Packing group | I |
| Storage class | 8B - Non-combustible corrosive hazardous materials |
| Hazardous substances data | 7446-11-9(Hazardous Substances Data) |
| REACH registrations | Active |
Safety & Regulations
| GHS classification | This chemical does not meet GHS hazard criteria for 14.9% (75 of 503) of reports.DangerH314 (85.1%): Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]P203, P260, P261, P264, P264+P265, P271, P273, P280, P284, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P318, P319, P320, P321, P363, P391, P403+P233, P405, and P501 (click each P-code to see the statement)Aggregated GHS information provided per 503 reports by companies from 22 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies. |
|---|---|
| Hazards Identification | Toxic/poison by inhalation (TIH/PIH) |
| Regulatory information | Chemical: Sulfur trioxideStatus: Active Update: 21-11-2022 https://echa.europa.eu/registration-dossier/-/registered-dossier/15436Sulfur trioxide: Does not have an individual approval but may be used as a component in a product covered by a group standard. It is not approved for use as a chemical in its own right.The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.) |
| DOT label | Corrosive Poison Inhalation Hazard |
| Fire hazards | Fire risk in contact with organic materials. An explosive increase in vapor pressure occurs when the alpha form melts. Combines with water with explosive violence, forming sulfuric acid. May ignite other combustible materials (wood, paper, oil, etc.). Flammable poisonous gases may accumulate in tanks and hopper cars. Runoff to sewer may create fire or explosion hazard. Forms sulfuric acid on contact with water. Avoid water and organic materials. On exposure to air, it absorbs moisture and emits dense white fumes. (EPA, 1998)· EXCEPT FOR ACETIC ANHYDRIDE (UN1715), THAT IS FLAMMABLE, some of these materials may burn, but none ignite readily.Not combustible. Gives off irritating or toxic fumes (or gases) in a fire. Many reactions may cause fire or explosion. Heating will cause rise in pressure with risk of bursting. Risk of fire and explosion on contact with bases, combustible substances, reducing agents, water or organic materials. |
| Fire potential | Material itself does not burn or burns with difficulty. |
| Health hazards | This material is highly toxic. It is an irritant and corrosive to mucous membranes. Poisonous if inhaled or swallowed. Contact causes severe burns to skin and eyes. (EPA, 1998)· CORROSIVE and/or TOXICinhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. |
| Hazards summary | Highly corrosive to skin[Quick CPC] Can cause severe coughing at a concentration of 1 ppm[HSDB] When dry, rapidly absorbs moisture from air evolving dense white fumesReacts explosively with water forming sulfuric acid[Merck Index] A strong oxidant that poses a fire and explosion hazard on contact with organic materialsCorrosive to skin, eyes, and respiratory tractRepeated or prolonged exposure to aerosol may cause effects to the lungs and erosion of teeth[ICSC] Concentrations of 1 ppm may cause coughing, choking, and severe discomfortCauses severe burns to skin and eyesInhalation causes severe irritation and may cause pulmonary edemaCauses erosion and discoloration of teethHealth effects basically the same as those for sulfuric acid[IUCLID] Causes diffuse hepatitis, changes in bronchi, and other endocrine changes in inhalation lethal-concentration studies of guinea pigs[RTECS] See Sulfuric acid.The major hazards encountered in the use and handling of sulfur trioxide stem from its toxicologic properties and reactivity. Toxic by all routes (ie, inhalation, ingestion, and dermal contact), exposure to this colorless-to-white, crystalline solid may occur from its use in the sulfonation of oils and detergents, in the manufacture of sulfuric acid and explosives, and in solar energy collectors. Effects from exposure may include burns to the eyes, skin, and mucous membranes, shortness-of-breath, chest pain, and pulmonary edema. In activities and situations where over-exposure may occur, wear chemical protective clothing and a self-contained breathing apparatus. If contact should occur, irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes, and wash exposed skin thoroughly with soap and water. Contaminated clothing should be removed and left at the worksite for cleaning. While sulfur trioxide itself burns with great difficulty, it may react violently (explosively) with water, giving off heat and light. Also, organic materials, particularly those containing adsorbed or absorbed moisture, may be ignited by sulfur trioxide. For fires involving sulfur trioxide, extinguish with agent suitable for surrounding materials. If water is used, apply in flooding quantities as a fog, and from as far a distance as possible. Use dikes to prevent sulfur trioxide from entering water sources and sewers. Sulfur trioxide may be shipped domestically via air (cargo only), rail (cargo only), road, and water, in containers bearing the label, "Corrosive." Sulfur trioxide should be stored in air-tight containers, away from moisture. Before implementing land disposal of sulfur trioxide waste, consult with environmental regulatory agencies for guidance. |
| DOT ID and guide | 1829 137 |
| Reactive group | Acids, Strong Oxidizing |
| UN classification | UN Hazard Class: 8UN Pack Group: I |
| Special Reports | U.S. Dept Health & Human Services/Agency for Toxic Substances & Disease RegistryToxicological Profile for Sulfur Trioxide and Sulfuric Acid (December 1998). The ATSDR toxicological profile succinctly characterizes the toxicologic and adverse health effects information for a hazardous substance.[Available from, as of October 15, 2009: http://www.atsdr.cdc.gov/toxpro2.html#] |
| Reactivity Alerts | Strong Oxidizing Agent |
| Fire fighting | Keep unnecessary people awayisolate hazard area and deny entry. Stay upwindkeep out of low areas. Ventilate closed spaces before entering them. Wear positive pressure breathing apparatus and special protective clothing.NO water. In case of fire in the surroundings, use appropriate extinguishing media. In case of fire: keep drums, etc., cool by spraying with water. NO direct contact with water. |
| First aid measures | Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer immediately for medical attention.Wear protective gloves when administering first aid. First rinse with plenty of water for at least 15 minutes, then remove contaminated clothes and rinse again. Refer immediately for medical attention .Rinse with plenty of water for several minutes (remove contact lenses if easily possible). Refer immediately for medical attention.Rinse mouth. Give nothing to drink. Do NOT induce vomiting. Refer immediately for medical attention. |
| Accidental release measures | · CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.· Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. |
| First aid | Warning: Sulfur trioxide is extremely corrosive. Caution is advised.General First Aid: |
| Safe storage | Refer to the manufacturer's instructions for proper storage conditions. Dry. Well closed. Store only in original packaging. Separated from food and feedstuffs and incompatible materials. See Chemical Dangers. Store only if stabilized. |
| Exposure control and personal protection | · Wear positive pressure self-contained breathing apparatus (SCBA).TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016]. |
| Fire fighting procedures | If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire ... Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible.NO hydrous agents. NO water. In case of fire in the surroundings: use appropriate extinguishing media ... Cool drums, etc., by spraying with water but avoid contact of the substance with water. |
| Storage conditions | /When/ stabilized, must be kept warm to liquefy, but under 40 °C. |
| Cleanup methods | SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.Evacuate danger area! Consult an expert! Do NOT absorb in saw-dust or other combustible absorbents. Absorb remaining liquid in dry sand or inert absorbent and remove to safe place. Ventilation. NEVER direct water jet on liquid. Do NOT let this chemical enter the environment. |
| Nonfire spill response | Excerpt from ERG Guide 137 [Substances - Water-Reactive - Corrosive]: |
| Disposal methods | SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air qualitypotential migration in soil or watereffects on animal and plant lifeand conformance with environmental and public health regulations. |
| Spillage disposal | Evacuate danger area! Consult an expert! Personal protection: chemical protection suit including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Do NOT wash away into sewer. Ventilation. Collect leaking liquid in covered containers. Absorb remaining liquid in dry sand or inert absorbent. Do NOT absorb in saw-dust or other combustible absorbents. Then store and dispose of according to local regulations. |
| Environmental fate | Atmospheric Fate: Sulfur trioxide is a highly reactive gas, and in the presence of moisture in the air it is rapidly hydrated to sulfuric acid. In the air, therefore, it is sulfuric acid in the form of an aerosol that is found rather than sulfur trioxide, and in general, it is associated with other pollutants in droplets or solid particles extending over a wide range of sizes. |
| Adverse effects | Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation. |
| Exposure routes | Serious local effects by all routes of exposure. The substance can be absorbed into the body by inhalation of its vapour. |
| Signs and Symptoms | Cough. Sore throat. Burning sensation. Shortness of breath. Laboured breathing.Redness. Pain. Blisters. Serious skin burns.Redness. Pain. Severe burns.Burns in mouth and throat. Burning sensation behind the breastbone. Abdominal pain. Vomiting. Shock or collapse. |
| ICSC Environmental Data | The substance is harmful to aquatic organisms. |
| Human Toxicity Excerpts | /SIGNS AND SYMPTOMS/ Sulfur trioxide and sulfuric acid mists are strongly irritants, and inhaling concn of approximately 3 mg/cu m causes a choking sensation. Persons accustomed to the exposure are unable to notice concn at this order of magnitude. Sulfur trioxide is irritating and corrosive to all mucous surfaces and causes inflammation of the upper respiratory tract and possible lung injury./SIGNS AND SYMPTOMS/ Lungs may be affected by repeated or prolonged exposure to an aerosol of this substance. Risk of tooth erosion upon repeated or prolonged exposure to an aerosol of this substance. Strong inorganic acid mists containing this substance are carcinogenic to humans./SIGNS AND SYMPTOMS/ Irritant and corrosive to mucous membranes. May cause coughing, choking and severe discomfort in a concn of 1 ppm./SIGNS AND SYMPTOMS/ Sulfur trioxide causes pulmonary skin and eye damage since it forms sulfuric acid.For more Human Toxicity Excerpts (Complete) data for Sulfur trioxide (10 total), please visit the HSDB record page. |
| Non-Human Toxicity Excerpts | /GENOTOXICITY/ The 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation and DNA damage by sulfur trioxide anion radicals (SO3.-) were investigated using ESR spin trapping, HPLC, and electrophoretic assays. Sulfite (SO3(2-) autoxidation generated both hydroxyl (.OH) and SO3.- radicals. Oxidation of SO3(2-) by chromium (VI) generated only SO3.- with much enhanced yield. Incubation of 2'-deoxyguanosine (dG) with SO3(2-) generated 8-OHdG albeit at low yield. Chromium (VI) enhanced the yield four-fold. Electrophoretic assays showed that SO3.- radicals generated by chromium (VI) oxidation of SO3(2-) caused DNA double strand breaks. The results demonstrate that SO3.- radicals are capable of causing dG hydroxylation and DNA double strand breaks. |
| Probable Routes of Human Exposure | NIOSH (NOES Survey 1981-1983) has statistically estimated that 56,102 workers (3,077 of these were female) were potentially exposed to sulfur trioxide in the US(1). |
| Antidote and Emergency Treatment | Treatment includes the use of oxygen, decontamination with special attention to the eyes, and monitoring for hypoxic ischemia. Treatment should include use of beta-agonists for bronchospasm, repeat pulmonary function tests, and monitoring for delayed pulmonary edema. Steroids, antibiotics, and nebulized sodium bicarbonate have not been adequately studied.Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Inorganic acids and related compounds/Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist respirations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. Activated charcoal is not effective. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Do not attempt to neutralize because of exothermic reaction. Cover skin burns with dry, sterile dressings after decontamination ... . /Inorganic acids and related compounds/Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Early intubation, at the first sign of upper airway obstruction, may be necessary. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's(LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Inorganic acids and related compounds/ |
| Toxicity Data | LCLo (guinea pig) = 30 mg/m3/6hr |
| RAIS Toxicity Values | 0.12CALEPA0.001 |
| Non-Human Toxicity Values | LC50 Rat/male inhalation 1375 mg SO3/cu m 1 hrLC50 Rat/female inhalation 1136 mg SO3/cu m 1 hr |
| DHS Chemicals of Interest (COI) | Sulfur trioxide110000Toxic chemical that can be released at a facility. |
| Personal protective equipment (PPE) | Faceshields, Gloves, Goggles |
| Water hazard class (WGK) | 1 |
| TSCA inventory status | TSCA listed |
| RTECS number | WT4830000 |
| UN transport number | UN 1829 (SULPHUR TRIOXIDE, STABILIZED) |
| Risk statements (R) | 45-8-14-26-34-37-35 |
| Signal word | Danger |
| GHS pictogram | GHS05 |
| Hazard symbols | O,T+,C |
| Safety statements (S) | 53-17-26-36/37/39-45-8-25-30 |
| Hazard class | 8Eye Dam. 1Skin Corr. 1ASTOT SE 3 |
| Storage class | 8B - Non-combustible corrosive hazardous materials |
| Packing group | I |
| Target organs | Respiratory system |
| GHS hazard statements | H314-H335 |
| REACH registrations | Active |
| GHS precautionary statements | P260-P264-P280-P261-P271-P301+P330+P331-P303+P361+P353-P363-P304+P340-P310-P305+P351+P338-P312-P405-P403+P233-P501 |
| Hazardous substances data | 7446-11-9(Hazardous Substances Data) |
Applications & Uses
Uses
Sulfur trioxide may be used in the synthesis of methane sulfonic acid (MSA) by sulfonating methane. it may also be used in the synthesis of fluorinated β-sultones by reacting with fluoroolefins.
Uses
Sulfur trioxide is used as an intermediate in the manufacture of sulphuric acid and oleum for sulphonation, in particular, of dyes and dye-stuffs, and for the production of anhydrous nitric acid and explosives. Solid Sulfur trioxide is marketed under such names as Sulphan and Triosul, and is used primarily for sulphonation of organic acids. Sulphur tetrafluoride is a fluorinating agent. Sulphur hexafluoride serves as a gaseous insulator in high-voltage electric installations. Sulphyryl fluoride is used as an insecticide and a fumigant. Sulfonation of organic compounds, especially nonionic detergents, solar energy collectors. It is usually generated in the plant where it is to be used.
General Description
Sulfur trioxide, is a colorless to white crystalline solid which will fume in air. Often shipped with inhibitor to prevent polymerization. Sulfur trioxide reacts violently with water to form sulfuric acid with the release of heat. Sulfur trioxide is corrosive to metals and tissue. Sulfur trioxide causes eye and skin burns. Ingestion causes severe burns of mouth esophagus and stomach. The vapor is very toxic by inhalation. Sulfur trioxide is a fire risk when in contact with organic materials such as wood, cotton, fiberboard, etc.