Thiourea dioxide

Last updated
Thiourea dioxide
SURDOX.png
Thiox sample.jpg
Names
Preferred IUPAC name
Amino(imino)methanesulfinic acid
Other names
Thiourea dioxide, DegaFAS, Reducing Agent F, Depilor, Formamidine Sulfinic Acid
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.015.598 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/CH4N2O2S/c2-1(3)6(4)5/h(H3,2,3)(H,4,5)
    Key: FYOWZTWVYZOZSI-UHFFFAOYSA-N
  • C(=N)(N)S(=O)O
Properties
CH4N2O2S
Molar mass 108.12 g·mol−1
AppearanceWhite powder
Melting point 126 °C (259 °F; 399 K)
3.0 g/100 mL
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-acid.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg
Danger
H252, H302, H315, H318, H332, H335, H373
P235+P410, P270, P280, P305+P351+P338, P310, P407, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Thiourea dioxide or thiox is an organosulfur compound that is used in the textile industry. [1] It functions as a reducing agent. [2] It is a white solid, and exhibits tautomerism.[ citation needed ]

Contents

Structure

The structure of thiourea dioxide depends on its environment. Crystalline and gaseous thiourea dioxide adopts a structure with C2v symmetry. Selected bond lengths: S-C = 186, C-N = 130, and S-O = 149 pm. The sulfur center is pyramidal. The C-S bond length is more similar to that of a single bond. For comparison, the C=S bond in thiourea is 171 pm. [3] [4] The long C-S bond indicates the absence of C=S character. Instead the bonding is described with a significant contribution from a dipolar resonance structure with multiple bonding between C and N. One consequence of this bonding is the planarity of the nitrogen centers. [5] In the presence of water or DMSO, thiourea dioxide converts to the tautomer, a sulfinic acid, (H2N)HN=CS(O)(OH), named formamidine sulfinic acid. [5]

Structure of the sulfinic acid tautomer of thiourea dioxide, as exists in aqueous solution Thiourea dioxide.svg
Structure of the sulfinic acid tautomer of thiourea dioxide, as exists in aqueous solution

Synthesis

Thiourea dioxide was first prepared in 1910 by the English chemist Edward de Barry Barnett. [6]

Thiourea dioxide is prepared by the oxidation of thiourea with hydrogen peroxide. [7]

(NH2)2CS + 2H2O2 → (NH)(NH2)CSO2H + 2H2O

The mechanism of the oxidation has been examined. [8] An aqueous solution of thiourea dioxide has a pH about 6.5 at which thiourea dioxide is hydrolyzed to urea and sulfoxylic acid. It has been found that at pH values of less than 2, thiourea and hydrogen peroxide react to form a disulfide species. It is therefore convenient to keep the pH between 3 and 5 and the temperature below 10 °C. [9] It can also be prepared by oxidation of thiourea with chlorine dioxide. [10] The quality of the product can be assessed by titration with indigo. [7]

Uses

Thiourea dioxide is used in reductive bleaching in textiles. [11] Thiourea dioxide has also been used for the reduction of aromatic nitroaldehydes and nitroketones to nitroalcohols. [12]

Related Research Articles

<span class="mw-page-title-main">Thiol</span> Any organic compound having a sulfanyl group (–SH)

In organic chemistry, a thiol, or thiol derivative, is any organosulfur compound of the form R−SH, where R represents an alkyl or other organic substituent. The −SH functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols, and the word is a blend of "thio-" with "alcohol".

<span class="mw-page-title-main">Sodium percarbonate</span> Chemical compound

Sodium percarbonate, or sodium carbonate peroxide is a chemical substance with formula Na
2
H
3
CO
6
. It is an adduct of sodium carbonate and hydrogen peroxide whose formula is more properly written as 2 Na
2
CO
3
 · 3 H
2
O
2
. It is a colorless, crystalline, hygroscopic and water-soluble solid. It is sometimes abbreviated as SPC. It contains 32.5% by weight of hydrogen peroxide.

<span class="mw-page-title-main">Tautomer</span> Structural isomers of chemical compounds that readily interconvert

Tautomers are structural isomers of chemical compounds that readily interconvert. The chemical reaction interconverting the two is called tautomerization. This conversion commonly results from the relocation of a hydrogen atom within the compound. The phenomenon of tautomerization is called tautomerism, also called desmotropism. Tautomerism is for example relevant to the behavior of amino acids and nucleic acids, two of the fundamental building blocks of life.

<span class="mw-page-title-main">Thiourea</span> Organosulfur compound (S=C(NH2)2)

Thiourea is an organosulfur compound with the formula SC(NH2)2 and the structure H2N−C(=S)−NH2. It is structurally similar to urea, except that the oxygen atom is replaced by a sulfur atom ; however, the properties of urea and thiourea differ significantly. Thiourea is a reagent in organic synthesis. Thioureas are a broad class of compounds with the general structure R2N−C(=S)−NR2.

<span class="mw-page-title-main">Sulfamic acid</span> Chemical compound

Sulfamic acid, also known as amidosulfonic acid, amidosulfuric acid, aminosulfonic acid, sulphamic acid and sulfamidic acid, is a molecular compound with the formula H3NSO3. This colourless, water-soluble compound finds many applications. Sulfamic acid melts at 205 °C before decomposing at higher temperatures to water, sulfur trioxide, sulfur dioxide and nitrogen.

<span class="mw-page-title-main">Sulfoxide</span> Organic compound containing a sulfinyl group (>SO)

In organic chemistry, a sulfoxide, also called a sulphoxide, is an organosulfur compound containing a sulfinyl functional group attached to two carbon atoms. It is a polar functional group. Sulfoxides are oxidized derivatives of sulfides. Examples of important sulfoxides are alliin, a precursor to the compound that gives freshly crushed garlic its aroma, and dimethyl sulfoxide (DMSO), a common solvent.

<span class="mw-page-title-main">Selenium dioxide</span> Chemical compound

Selenium dioxide is the chemical compound with the formula SeO2. This colorless solid is one of the most frequently encountered compounds of selenium. It is used in making specialized glasses as well as a reagent in organic chemistry.

<span class="mw-page-title-main">Potassium cyanate</span> Chemical compound

Potassium cyanate is an inorganic compound with the formula KOCN. It is a colourless solid. It is used to prepare many other compounds including useful herbicide. Worldwide production of the potassium and sodium salts was 20,000 tons in 2006.

<span class="mw-page-title-main">Isocyanic acid</span> Chemical compound (H–N=C=O)

Isocyanic acid is a chemical compound with the structural formula HNCO, which is often written as H−N=C=O. It is a colourless, volatile and poisonous substance, with a boiling point of 23.5 °C. It is the predominant tautomer and an isomer of cyanic acid (aka. cyanol).

<span class="mw-page-title-main">2-Iodoxybenzoic acid</span> Chemical compound

2-Iodoxybenzoic acid (IBX) is an organic compound used in organic synthesis as an oxidizing agent. This periodinane is especially suited to oxidize alcohols to aldehydes. IBX is prepared from 2-iodobenzoic acid, potassium bromate, and sulfuric acid. Frigerio and co-workers have also demonstrated, in 1999 that potassium bromate may be replaced by commercially available Oxone. One of the main drawbacks of IBX is its limited solubility; IBX is insoluble in many common organic solvents. In the past, it was believed that IBX was shock sensitive, but it was later proposed that samples of IBX were shock sensitive due to the residual potassium bromate left from its preparation. Commercial IBX is stabilized by carboxylic acids such as benzoic acid and isophthalic acid.

Organoselenium chemistry is the science exploring the properties and reactivity of organoselenium compounds, chemical compounds containing carbon-to-selenium chemical bonds. Selenium belongs with oxygen and sulfur to the group 16 elements or chalcogens, and similarities in chemistry are to be expected. Organoselenium compounds are found at trace levels in ambient waters, soils and sediments.

<span class="mw-page-title-main">2-Pyridone</span> Chemical compound

2-Pyridone is an organic compound with the formula C
5
H
4
NH(O)
. It is a colourless solid. It is well known to form hydrogen bonded dimers and it is also a classic case of a compound that exists as tautomers.

<span class="mw-page-title-main">Sulfinic acid</span> Class of chemical compounds

Sulfinic acids are oxoacids of sulfur with the structure RSO(OH). In these organosulfur compounds, sulfur is pyramidal.

<span class="mw-page-title-main">Thioureas</span> Organosulfur compounds with an >NC(=S)N< structure

In organic chemistry, thioureas are members of a family of organosulfur compounds with the formula S=C(NR2)2 and structure R2N−C(=S)−NR2. The parent member of this class of compounds is thiourea. Substituted thioureas are found in several commercial chemicals.

Pyridine-<i>N</i>-oxide Chemical compound

Pyridine-N-oxide is the heterocyclic compound with the formula C5H5NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine. It was originally prepared using peroxyacids as the oxidising agent. The compound is used infrequently as an oxidizing reagent in organic synthesis.

<span class="mw-page-title-main">Squaramide</span> Chemical compound

Squaramide is the organic compound with the formula O2C4(NH2)2. Not an amide in the usual sense, it is a derivative of squaric acid wherein the two OH groups are replaced by NH2 groups. Squaramides refer to a large class of derivatives wherein some of the H's are replaced by organic substituents. Exploiting their rigid planar structures, these compounds are of interest as hydrogen-bond donors in supramolecular chemistry and organocatalysis. Squaramides exhibit 10-50x greater affinity for halides than do thioureas. Squaramides also find application in medicinal chemistry, metabolomics and material science due to their ability to selectively conjugate amines

<span class="mw-page-title-main">Selenourea</span> Chemical compound

Selenourea is the organoselenium compound with the chemical formula Se=C(NH2)2. It is a white solid. This compound features a rare example of a stable, unhindered carbon-selenium double bond. The compound is used in the synthesis of selenium heterocycles. Selenourea is a selenium analog of urea O=C(NH2)2. Few studies have been done on the compound due to the instability and toxicity of selenium compounds. Selenourea is toxic if inhaled or consumed.

<span class="mw-page-title-main">Trifluoroperacetic acid</span> Chemical compound

Trifluoroperacetic acid is an organofluorine compound, the peroxy acid analog of trifluoroacetic acid, with the condensed structural formula CF
3
COOOH
. It is a strong oxidizing agent for organic oxidation reactions, such as in Baeyer–Villiger oxidations of ketones. It is the most reactive of the organic peroxy acids, allowing it to successfully oxidise relatively unreactive alkenes to epoxides where other peroxy acids are ineffective. It can also oxidise the chalcogens in some functional groups, such as by transforming selenoethers to selones. It is a potentially explosive material and is not commercially available, but it can be quickly prepared as needed. Its use as a laboratory reagent was pioneered and developed by William D. Emmons.

<span class="mw-page-title-main">Sulfoxylic acid</span> Chemical compound

Sulfoxylic acid (H2SO2) (also known as hyposulfurous acid or sulfur dihydroxide) is an unstable oxoacid of sulfur in an intermediate oxidation state between hydrogen sulfide and dithionous acid. It consists of two hydroxy groups attached to a sulfur atom. Sulfoxylic acid contains sulfur in an oxidation state of +2. Sulfur monoxide (SO) can be considered as a theoretical anhydride for sulfoxylic acid, but it is not actually known to react with water.

<span class="mw-page-title-main">Metal peroxide</span>

Metal peroxides are metal-containing compounds with ionically- or covalently-bonded peroxide (O2−
2
) groups. This large family of compounds can be divided into ionic and covalent peroxide. The first class mostly contains the peroxides of the alkali and alkaline earth metals whereas the covalent peroxides are represented by such compounds as hydrogen peroxide and peroxymonosulfuric acid (H2SO5). In contrast to the purely ionic character of alkali metal peroxides, peroxides of transition metals have a more covalent character.

References

  1. Fischer, Klaus (2003). "Textile Auxiliaries". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a26_227. ISBN   9783527303854. OCLC   55738480. Archived from the original on 2022-06-18. Retrieved 2022-06-18.
  2. Milne, George W. A. (11 July 2005). Gardner's Commercially Important Chemicals: Synonyms, Trade Names, and Properties. Hoboken, New Jersey, USA: Wiley-Interscience. doi:10.1002/0471736627.ch1. ISBN   9780471735182. OCLC   57392953. Archived from the original on 18 June 2022. Retrieved 18 June 2022.
  3. Sullivan, R. A. L.; Hargreaves, A. (1962). "The Crystal and Molecular Structure of Thiourea Dioxide". Acta Crystallographica. 15 (7): 675–682. Bibcode:1962AcCry..15..675S. doi: 10.1107/S0365110X62001851 .
  4. Chen, I-C.; Wang, Y. (1984). "Reinvestigation of the Structure of Thiourea S,S-Dioxide, CH4N2O2S". Acta Crystallographica. 40 (11): 1937–1938. Bibcode:1984AcCrC..40.1937C. doi:10.1107/S010827018401012X.
  5. 1 2 Makarov, S. V. (2001). "Recent Trends in the Chemistry of Sulfur-Containing Reducing Agents". Russian Chemical Reviews. 70 (10): 885–895. Bibcode:2001RuCRv..70..885M. doi:10.1070/RC2001v070n10ABEH000659. S2CID   250741549.
  6. Barnett first prepared thiourea dioxide ("aminoiminomethanesulphinic acid") by oxidizing thiourea ("thiocarbamide") with hydrogen peroxide ("hydrogen dioxide"). See: Barnett, Edward de Barry (1910) "The action of hydrogen dioxide on thiocarbamides," Archived 2020-06-06 at the Wayback Machine Journal of the Chemical Society, Transactions, 97 : 63–65.
  7. 1 2 D. Schubart "Sulfinic Acids and Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wiley-VCH, Weinheim. doi : 10.1002/14356007.a25_461
  8. Hoffmann, Michael; Edwards, John O. (1977). "Kinetics and Mechanism of the Oxidation of Thiourea and N,N'-dialkylthioureas by Hydrogen Peroxide". Inorganic Chemistry. 16 (12): 3333–3338. doi:10.1021/ic50178a069.
  9. USpatent 2783272,James H. Young,"PRODUCTION OF FORMAMIDINE SULFINIC ACID",issued 1957-2-26
  10. Rábai, G.; Wang, R. T.; Kustin, Kenneth (1993). "Kinetics and mechanism of the oxidation of thiourea by chlorine dioxide" International Journal of Chemical Kinetics. Volume 25: 53–62. doi : 10.1002/kin.550250106
  11. Hebeish, A.; El-Rafie, M. H.; Waly, A.; Moursi, A. Z. (1978). "Graft copolymerization of vinyl monomers onto modified cotton. IX. Hydrogen peroxide–thiourea dioxide redox system induced grafting of 2-methyl-5-vinylpyridine onto oxidized celluloses". Journal of Applied Polymer Science. 22 (7): 1853–1866. doi:10.1002/app.1978.070220709.
  12. Sambher, Shikha; Baskar, Chinnappan; Dhillon, Ranjit S. (22 May 2009). "Chemoselective reduction of carbonyl groups of aromatic nitro carbonyl compounds to the corresponding nitroalcohols using thiourea dioxide". Arkivoc. 2009 (10): 141–145. doi: 10.3998/ark.5550190.0010.a14 . hdl: 2027/spo.5550190.0010.a14 .