14265-45-3

Basic information

• Product Name: sulfur trioxide
• Synonyms: Sulfite;SULPHITE
• CAS NO: 14265-45-3
• Molecular Formula: O₃S
• Molecular Weight: 80.06
• EINECS: 231-197-3
• Mol File: 14265-45-3.mol
• Article Data: 24

Chemical Properties

• Boiling Point: °Cat760mmHg
• Flash Point: °C
• Appearance: /
• Density: g/cm³
• Vapor Pressure: 371mmHg at 25°C
• Refractive Index: 1.662
• CAS DataBase Reference: sulfur trioxide(CAS DataBase Reference)
• NIST Chemistry Reference: sulfur trioxide(14265-45-3)
• EPA Substance Registry System: sulfur trioxide(14265-45-3)

Safety Data

• Hazardous Substances Data: 14265-45-3(Hazardous Substances Data)

Usage

Description

Endogenous sulfite is generated as a consequence of the body’’s normal processing of sulfur-containing amino acids. In addition, as discussed below, sulfite can be produced by neutrophils. Sulfites occur as a consequence of fermentation and also naturally in a number of foods and beverages. As food additives, sulfating agents were first used in 1664, and approved for use in the United States in the 1800s. Sulfite is also noted as a water treatment additive, for example, to control oxygen levels in power plant boiler water. Further, sulfur dioxide is acommonair pollutant produced by numerous processes (burning sulfurbearing coal, smelting sulfide ores, etc.), and may enter the body via inhalation. Sulfur dioxide has been reported to react with water in the ambient air and in the respiratory tract’s mucous membranes to form sulfite and bisulfite ions.

Uses

Inorganic sulfites and bisulfites (such as sodium sulfite, Na2O3S) are used in photography, the bleaching of wool, and as preservatives in foods, beverages, and medications. They act as effective antioxidant compounds and are also used in the manufacture of pulp for paper and wood products. Their preservative properties include controlling microbial growth and the prevention of browning and spoilage. Under the US Federal Food, Drug, and Cosmetic Act, sulfites are permitted for use as preservatives in food. Like other ingredients, sulfites must be declared in the ingredient statement when added to a food product. In addition, sodium sulfite, ammonium sulfite, sodium bisulfite, potassium bisulfite, ammonium bisulfite, sodium metabisulfite, and potassium metabisulfite are inorganic salts that function as reducing agents in cosmetic formulations. All except sodium metabisulfite also function as hair waving/straightening agents. In addition, sodium sulfite, potassium sulfite, sodium bisulfite, and sodium metabisulfite function as antioxidants in cosmetics. All except ammonium sulfite are widely used in hair care products.

Definition

ChEBI: Sulfite is an inorganic anion, which is the conjugate base of hydrogen sulfite.

Environmental Fate

Sulfites are generally soluble compounds that interact with the environment through a variety of processes. The primary function of sulfites is that of a reducing agent, which can remove dissolved oxygen from waterways. This reduction of dissolved oxygen (normally produced via normal aeration through water movement, falls and disturbances, etc.) in turn generates a favorable environment for anaerobic bacteria, disrupting the local microbiota. Decreases in dissolved oxygen caused by the presence of sulfites, typically below 5 ppm dissolved oxygen, can negatively affect fish and other organisms present in polluted waterways. Another effect of sulfite contamination of waterways is the production of hydrogen sulfide gas, which is a by-product of sulfite-induced redox processes. Flue gas desulfurization is an industrial process that produces calcium sulfite (CaSO3) as a by-product. This relatively insoluble sulfite, when deposited in soils, can cause a general shift in local microbiot a; however, calcium sulfite readily undergoes oxidation to calcium sulfate (gypsum), which is generally accepted as a remediation material for poor quality soils. While the resulting gypsum can have beneficial effects on soils for agricultural purposes, large quantities of sulfite species over longer time spans can be expected to directly affect microbial communities in soils, even after conversion to the more benign calcium sulfate. Consequently, the presence of calcium sulfate may produce blooming as a result of oxygen- and sulfurenriched soils and adjoining waterways.

Toxicity evaluation

Although the physiological basis for sulfite sensitivity is still poorly understood, clinical observations have established that certain medical conditions are associated with a predisposition to sulfite hypersensitivity. Approximately 500 000 individuals in the United States (<0.05% of the population) are at higher risk because they are asthma sufferers who are steroid dependent or have general airway hypersensitivity. Studies suggest that sulfur dioxide is the agent that causes the highest physiological response. It has been shown that bronchoconstriction as a result of SO2 exposure is controlled by chemosensitive receptors in the tracheobronchial tree. Sensory C-fiber receptors and rapidly activating receptors are sensitive to gases such as SO2, and are found throughout the respiratory tract. Activation of these receptors triggers central nervous system reflexes that culminate in bronchoconstriction, mucosal vasodilation, cough, mucus secretion, apnea, and potential of bradycardia and changes in blood pressure. Inhaled sulfur dioxide elicited a stronger reaction in sulfite oxidase–deficient rats than endogenously accumulated sulfites and S-sulfocysteine (a reaction product of sulfite with cysteine residues in proteins). Bisulfites result in three main reactions with biomolecules: sulfonation (sulfitolysis), autooxidation (and generation of free radicals), and cytosine addition. Sulfonation reactions in the body resulting from exogenous bisulfites can be long-lived in vivo. Autooxidation reactions induced by bisulfites may result in lipid peroxidation, and possible damage to plasma membranes as a result. Sulfite addition to cytosine creates uracil, producing a mutation at that site.

InChI:InChI=1/O3S/c1-4(2)3

Upstream product

• 7783-06-4 hydrogen sulfide 
• 1423-18-3 bis(perfluoroisopropyl)sulfurdifluoride 
• 20901-21-7 disulfur monoxide 
• 1313-82-2 sodium sulfide 
• 7757-83-7 sodium sulfite 
• 80937-33-3 oxygen 
• 201230-82-2 carbon monoxide 
• 14701-22-5 nickel(II) 
• 14844-07-6 dithionite^(2-) 
• 7758-99-8 copper(II) sulfate 
• 1333-74-0 hydrogen 
• 14383-50-7 thiosulphate ion 
• 1310-73-2 sodium hydroxide 
• 10025-67-9 disulfur dichloride 

Downstream Products

• 75-07-0 acetaldehyde 
• 126901-00-6 iodosulfate ion 
• 14362-44-8 iodide 
• 7727-37-9 nitrogen 
• 7446-11-9 sulfur trioxide 
• 10024-97-2 dinitrogen monoxide 
• 7446-09-5 sulfur dioxide 
• 14808-79-8 Sulfate 
• 16887-00-6 chloride 
• 14866-68-3 chlorate 
• 7782-49-2 selenium 
• 10097-32-2 bromide 
• 23134-05-6 disulfite ion 
• 7704-34-9 sulfur 

Relevant articles and documents

Catalytic activity of CuS nanoparticles in hydrosulfide ions air oxidation

The most efficient technique for H2S removal from the wastewaters is the catalytic aeration of the wastewaters, i.e., H2S oxidation in air-saturated solutions in the presence of catalysts. Photophysical characteristics of colloidal CuS nanoparticles synthesized in various conditions and stabilized in aqueous solutions with sodium polyphosphate were studied. Hydrosulfide ions air oxidation in aqueous solutions at room temperatures and 1 atm proceeded with small rates in the absence of catalysis and increased, substantially upon the injection of CuS nanoparticles into a reacting mixture. The rate of HS- catalytic oxidation grew at an increase in molar CuS concentration, initial concentration of Na2S, volume fraction of oxygen in gas mixture bubbled into the reactor, and pH of a solution (≤ 11.9). A scheme for the mechanism of HS- catalytic oxidation was proposed. According to the scheme, HS- oxidation is a chain radical reaction initiated on the surface of CuS nanoparticles and propagated further in the bulk of a solution.

DNA damage induced by sulfite autoxidation catalyzed by copper(II) tetraglycine complexes

Copper(II)/(III) tetraglycine complexes were investigated for their ability to catalyze the autoxidation of sulfite resulting in oxidative DNA damage. The focus of this work is on DNA damage by Cu(III) and oxysulfur radicals formed by the oxidation of S(IV) oxides by dissolved oxygen in the presence of Cu(II) tetraglycine complexes. The results suggest that sulfite is rapidly oxidized by oxygen in the presence of Cu(II) complexes producing Cu(III) tetraglycine, which can be monitored spectrophotometrically at 365 nm. A synergistic effect of Cu(II) with a second metal ion (Ni(II), Co(II) or Mn(II) traces) was observed. The Royal Society of Chemistry 2005.

The preparation and properties of N-fluoroformyliminosulfur difluoride, SF2=NCOF

The inorganic isocyanates derived from silicon, phosphorus, and sulfur have been found to react readily with sulfur tetrafluoride to give, in common, the novel compound, N-fluoroformyliminosulfur difluoride, SF2=NCOF, the preparation and proper

Evidence for Multistep Reactions in the Iron(III) Catalysed Autoxidation of Sulphur(IV) Oxides: Possible Steps during Acid Rain Formation

Kinetic and spectroscopic evidence is presented for the formation and decomposition of iron(III)-sulphur(IV) transients during the iron(III) catalysed autoxidation of sulphur(IV) oxides in aqueous solution, for which four different reaction steps could be

Oxidation of thiocyanate with H2O2 catalyzed by [RuIII(edta)(H2O)]-

The [RuIII(edta)(H2O)]- (edta4- = ethylenediaminetetraacetate) complex is shown to catalyze the oxidation of thiocyanate (SCN-) with H2O2 mimicking the action of peroxidases. The kinetics of the catalytic oxidation process was studied by using stopped-flow and rapid scan spectrophotometry as a function of [RuIII(edta)], [H2O2], [SCN-], pH (3.2-9.1) and temperature (15-30 °C). Spectral analyses and kinetic data are suggestive of a catalytic pathway in which hydrogen peroxide reacts directly with thiocyanate coordinated to the RuIII(edta) complex. Catalytic intermediates such as [RuIII(edta)(OOH)]2- and [Ru V(edta)(O)]- were found to be non-reactive in the oxidation process under the specified conditions. Formation of SO 42- and OCN- was identified as oxidation products in ESI-MS experiments. A detailed mechanism in agreement with the spectral and kinetic data is presented. The Royal Society of Chemistry 2013.

Some perfluoroalkyliminosulfur derivatives

Trifluoromethyliminosulfur dichloride and pentafluoroethyliminosulfur dichloride are prepared by reaction of aluminum trichloride with trifluoromethyliminosulfur difluoride and pentafluoroethyliminosulfur difluoride, respectively. These imino dichlorides

177. Photoreduction of Thiosulfate in Semiconductor Dispersions

Conduction band electrons produced by band gap excitation of TiO2-particles reduce efficiently thiosulfate to sulfide and sulfite. This reaction is confirmed by electrochemical investigations with polycrystalline TiO2-electrodes.The valence ban

Light-Activated generation of nitric oxide (NO) and sulfite anion radicals (SO3-) from a ruthenium(ii) nitrosylsulphito complex

This manuscript describes the preparation of a new Ru(ii) nitrosylsulphito complex, trans-[Ru(NH3)4(isn)(N(O)SO3)]+ (complex 1), its spectroscopic and structural characterization, photochemistry, and thermal reactivity. Complex 1 was obtained by the reaction of sulfite ions (SO32-) with the nitrosyl complex trans-[Ru(NH3)4(isn)(NO)]3+ (complex 2) in aqueous solution resulting in the formation of the N-bonded nitrosylsulphito (N(O)SO3) ligand. To the best of our knowledge, only four nitrosylsulphito metal complexes have been described so far (J. Chem. Soc., Dalton Trans., 1983, 2465-2472), and there is no information about the photochemistry of such complexes. Complex 1 was characterized by spectroscopic means (UV-Vis, EPR, FT-IR, 1H-and 15N-NMR), elemental analysis and single-crystal X-ray diffraction. The X-ray structure of the precursor complex 2 is also discussed in the manuscript and is used as a reference for comparisons with the structure of 1. Complex 1 is water-soluble and kinetically stable at pH 7.4, with a first-order rate constant of 3.1 × 10-5 s-1 for isn labilization at 298 K (t1/2 ～ 373 min). Under acidic conditions (1.0 M trifluoroacetic acid), 1 is stoichiometrically converted into the precursor complex 2. The reaction of hydroxide ions (OH-) with 1 and with 2 yields the Ru(ii) nitro complex trans-[Ru(NH3)4(isn)(NO2)]+ with second-order rate constants of 2.1 and 10.5 M-1 s-1 (at 288 K), respectively, showing the nucleophilic attack of OH- at the nitrosyl in 2 (Ru-NO) and at the nitrosylsulphito in 1 (Ru-N(O)SO3). The pKa value of the-SO3 moiety of the N(O)SO3 ligand in 1 was determined to be 5.08 ± 0.06 (at 298 K). The unprecedented photochemistry of a nitrosylsulphito complex is investigated in detail with 1. The proposed mechanism is based on experimental (UV-Vis, EPR, NMR and Transient Absorption Laser Flash Photolysis) and theoretical data (DFT) and involves photorelease of the N(O)SO3- ligand followed by formation of nitric oxide (NO) and sulfite radicals (SO3-, sulfur trioxide anion radical).

Mechanism of decomposition of the human defense factor hypothiocyanite near physiological pH

Relatively little is known about the reaction chemistry of the human defense factor hypothiocyanite (OSCN-) and its conjugate acid hypothiocyanous acid (HOSCN), in part because of their instability in aqueous solutions. Herein we report that HOSCN/OSCN- can engage in a cascade of pH- and concentration-dependent comproportionation, disproportionation, and hydrolysis reactions that control its stability in water. On the basis of reaction kinetic, spectroscopic, and chromatographic methods, a detailed mechanism is proposed for the decomposition of HOSCN/OSCN- in the range of pH 4-7 to eventually give simple inorganic anions including CN -, OCN-, SCN-, SO32-, and SO42-. Thiocyanogen ((SCN)2) is proposed to be a key intermediate in the hydrolysis; and the facile reaction of (SCN) 2 with OSCN- to give NCS(=O)SCN, a previously unknown reactive sulfur species, has been independently investigated. The mechanism of the aqueous decomposition of (SCN)2 around pH 4 is also reported. The resulting mechanistic models for the decomposition of HOSCN and (SCN) 2 address previous empirical observations, including the facts that the presence of SCN- and/or (SCN)2 decreases the stability of HOSCN/OSCN-, that radioisotopic labeling provided evidence that under physiological conditions decomposing OSCN- is not in equilibrium with (SCN)2 and SCN-, and that the hydrolysis of (SCN)2 near neutral pH does not produce OSCN-. Accordingly, we demonstrate that, during the human peroxidase-catalyzed oxidation of SCN-, (SCN)2 cannot be the precursor of the OSCN- that is produced.