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EC / List no.: 217-157-8
CAS no.: 1758-73-2
Mol. formula: CH4N2O2S
Thiourea dioxide or thiox is an organosulfur compound that is used in the textile industry.
Thiourea dioxide functions as a reducing agent.
Thiourea dioxide is a white solid. The compound exhibits tautomerism.
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.
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.
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.
Synthesis
Thiourea dioxide was first prepared in 1910 by the English chemist Edward de Barry Barnett.
Thiourea dioxide is prepared by the oxidation of thiourea with hydrogen peroxide.
(NH2)2CS + 2H2O2 → (NH)(NH2)CSO2H + 2H2O
The mechanism of the oxidation has been examined.
An aqueous solution of thiourea dioxide has a pH about 6.5 at which thiourea dioxide is hydrolyzed to urea and sulfoxylic acid.
Thiourea dioxide has been found that at pH values of less than 2, thiourea and hydrogen peroxide react to form a disulfide species.
Thiourea dioxide is therefore convenient to keep the pH between 3 and 5 and the temperature below 10 °C.
Thiourea dioxide can also be prepared by oxidation of thiourea with chlorine dioxide.
The quality of the product can be assessed by titration with indigo.
Uses
Thiourea dioxide is used in reductive bleaching in textiles.
Thiourea dioxide has also been used for the reduction of aromatic nitroaldehydes and nitroketones to nitroalcohols
Thiourea dioxide appears as a white or light-yellow odorless crystalline powder. Mp:126°C. Soluble in water (27 g / L at room temperature).
Decomposes exothermically at temperatures above 126°C with the emission of noxious gases (sulfur oxides, ammonia, carbon monoxide, nitrogen oxides and hydrogen sulfide) and carbon dioxide.
Extended exposure to temperatures above 50°C and moisture may cause visible decomposition.
Irritating to skin and mucous membranes.
Corrosive to eye tissue. Used in leather processing, the paper industry, photographic industry, and in textile processing as a bleaching agent.
Industry Uses
Bleaching agents
Finishing agents
Consumer Uses
Paper products
General Manufacturing Information
Industry Processing Sectors
Paper manufacturing
Textiles, apparel, and leather manufacturing
Chemical Properties
white crystalline powder
Uses
Convenient reagent for the reduction of ketones to secondary alcohols.
Thiourea dioxide is an effective bleach when used alone or when used after hydrogen peroxide in a full bleaching process.
Bleaching with thiourea dioxide is not common practice but it is effective when used alone, and the process compares favorably with hydrogen peroxide bleaching.
A formulation can include a commercial thiourea dioxide product, wetting agent and EDTA sequestering agent.
Reductive bleaching is carried out at pH 7.0 at 70°C for 60 min .
General Description
A white or light-yellow odorless crystalline powder.
Melting Point:126°C.
Soluble in water (27 g / L at room temperature).
Decomposes exothermically at temperatures above 126°C with the emission of noxious gases (sulfur oxides, ammonia, carbon monoxide, nitrogen oxides and hydrogen sulfide) and carbon dioxide.
Extended exposure to temperatures above 50°C and moisture may cause visible decomposition.
Irritating to skin and mucous membranes.
Corrosive to eye tissue.
Used in leather processing, the paper industry, photographic industry, and in textile processing as a bleaching agent.
Air & Water Reactions
Soluble in water
Reactivity Profile
Thiourea dioxide is a reducing agent and a derivative of sulfinic acid (a weak inorganic acid).
Decolorizes and bleaches materials by chemical reduction.
Stable under normal temperatures and pressures.
May decompose on exposure to moist air or water.
Incompatible with strong oxidizing agents, strong bases.
Aqueous solutions are acidic and corrosive.
Purification Methods
Dissolve it in five parts of aqueous 1:1% NaHSO3 at 60-63o (charcoal), then allow it to crystallise slowly, with agitation, at 10o. Filter and dry it immediately at 60o
Thiourea Dioxide is a replacement for Sodium Hydrosulphite / Thiosulphite used in vat dyeing, discharge printing and general colour stripping on cellulose and protein fibres.
Thiourea dioxide is an active reducing agent which removes the oxygen from indigo when combined with Soda Ash.
Thiourea Dioxide is five times stronger than Sodium Hydrosulphite the alternative reducing agent.
Use 1 part Soda Ash to 4 parts Thiourea Dioxide to make a discharge paste for removing some synthetic dyes, especially Procion MX, from cellulose fibres.
Thiourea Dioxide is combined with Selectasine Indigo Discharge Medium at 8% of volume of discharge medium to activate it.
Stir until all crystals have dissolved.
Once activated, the discharge medium is effective for up to 18 hours.
Uses:
Thiourea dioxide, also referred to as ‘thiox’ or under the brand name is an effective, oxygen-reducing agent for use in indigo and woad (vat) dyeing.
Used in conjunction with sodium carbonate (‘soda ash’) it is reliable and straightforward to use.
Can be used as an alternative to sodium hydrosulphite (‘hydros’), or spectralite.
Application
Convenient reagent for the reduction of ketones to secondary alcohols.
1.Physical and Chemical Properties
Other Name: Formamidine sulfinic acid, Amino imino methanesulfinic acid
Appearance and Odor: White crystal powder, odorless
2. Specification:
Purity: 99.%Min
Thiourea: 0.10%Max
Moisture:0.05%Max
Iron(Fe):10ppm Max
Sulphate: 0.17%Max
3,Why Customers choose Thiourea Dioxide(TDO):
Sodium Hydrosulfite is being used in the textile industry as a reducing agent for dyeing vat and sulfur vat dyes; as a reducing-washing agent for fabricsn dyed with dispersion dyes; as a decolorizing agent for dyed fabrics; as a bleaching agent for wool, silk and polyamide fabrics; etc.
However, various handling problems are inherent in its use such as unstable storage life in powdered form, generation of obnoxious sulfurous acid gas, adsorption of moisture, generation of heat when in contact with water and possibility of igniting.
Furthermore, since it decomposes very quickly in aqueous solution, there is an added disadvantage of requiring several times more than its theoretical amount.
Its decomposition in chemical solution during storage for use in continuous dyeing of vat and sulfur vat dyes is also so great as to present considerable difficulties in maintaining its concentration.
We take great pleasure, therefore, in introducing to you our Thiourea dioxide, a reducing agent for overcoming all these difficulties mentioned above with Sodium Hydrosulfite.
Special Characteristics of Thiourea dioxide
1. Since it is a white powder incapable of any oxidative or reductive action alone, Thiourea dioxide has a very stable storage life.
2. Thiourea dioxide is not hygroscopic and is absolutely free from deliquescence of caking.
3. Thiourea dioxide does not generate heat when in contact with water or ignite under impact.
4. Thiourea dioxide does not emit obnoxious sulfurous gas like Sodium hydrosulfite.
5. Preparation of solution with Thiourea dioxide is simplified since far less amount is required than with Sodium Hydrosulfite.
6. An aqueous solution of Thiourea dioxide is not only very stable when stored but also when on fabrics regardless of what the PH is.
Hence process and quality controls in continuous dyeing, bleaching, reducing-washing and decolorizing operations are easy and dependable.
7. Thiourea dioxide shows very high reduction potential in aqueous solution.
Hence dyes difficult to reduce and decolorize with Sodium Hydrosulfite are possible with Thiourea dioxide.
Furthermore, wool can be bleached to a high level of brightness with Thiourea dioxide.
However, when using Thiourea dioxide as a reducing agent in dyeing vat dyes, an anti-reducing agent is necessary for preventing excessive reduction of indanthrone based dyes.
8. In bleaching wool with Thiourea dioxide, uniform dyeing is obtained due to its slow decomposition in bleaching solution.
Moreover, Thiourea dioxide can be used in continuous steam bleaching with far less shrinkage and damage than with Sodium Hydrosulfite.
9. Thiourea dioxide does good to the environment, not increase waste water pollution load, and conforms to the environmental protection requirements---save production cost.
Thiourea dioxide is a reducing agent for indigo and other vat dyes and is an excellent substitution for sodium hydrosulfite in color stripping and discharge.
Thiourea dioxide is safer to use, has a greater strength, and has a better shelf life.
Thiourea dioxide can be used for stripping cellulose fiber or bleaching wool or silk.
Thiourea dioxide must be used in a well ventilated area or outside.
Thiourea dioxide is a strong reductant.
Thiourea dioxide is used in leather processing industry, paper, pulp and board industry, photographic industry, textile processing industry, bleaching and reducing agents.
Thiourea dioxide is also a component of decolorisation agents.
The use of thiourea dioxide as reducing agent in the application of sulphur dyes: Thiourea dioxide was applied as reducing agent during the dyeing of cellulosic fibres with eight commercial sulphur dyes.
The same dyes were also applied frow dyebaths containing sodium sulphide.
Thiourea dioxide was found that the intensity and fastness properties of the dyeings by both methods were similar, although in some cases slight differences in shade were observed.
Analysis of the exhausted dyebaths indicates that thiourea dioxide may be considered as a more environmental friendly substitute for sodium sulphide during the application of sulphur dyes.
Thiourea Dioxide (Formamidinesulphinic Acid) A New Reducing Agent for Textile Printing:
Thiourea dioxide, an oxidation product of thiourea, is a reducing agent which is stable both in solid form and in cold aqueous solution.
Thiourea dioxide has a slight acidic reaction, and acquires full reducing power only when heated in aqueous solution to about 100°C.
This paper briefly describes the chemistry of thiourea dioxide, and dealB with it as a reducing agent for vat dyes in the direct and discharge printing of cellulose acetate, silk, and wool.
Owing to its acidic properties, these fibres can be printed with a minimum of degradation and great safety of production.
The new reducing agent has been tried on a practical scale, and results of trials are demonstrated.
Chemoselective reduction of carbonyl groups of aromatic nitro carbonyl compounds to the corresponding nitroalcohols using thiourea dioxide:
...Thiourea dioxide (TUDO) or formamidinesulfinic acid (FSA) - a commercially available reducing agent has vast applications for waste papers processing, wool bleaching, the reduction of ferredoxin, cyctochrome C and methaemoglobin.
Thiourea dioxide is also used for the reduction of organosulfur compounds (sulfylimines, sulfoxides, disulfides); for the synthesis of selenides and tellurides from the corresponding diselenides and ditellurides under phase transfer catalysis and the deoxygenation of -epoxy ketones.
Thiourea Dioxide otherwise known as Spectralite or THIOX chemically reduces oxygen from Indigo Dye VAT when using natural indigo dyes to dye fabrics or fibres such as silk, wool, cotton etc.
Spectralite is approximately x 5 more efficient at reducing oxygen that the alternative which is known as Sodium Dithionite (HYDROS).
When dyeing cotton it is important to also use Soda Ash to ensure the correct pH (alkalinity) of the dye bath.
Thiourea Dioxide must be handled with care, as can be harmful and hazardous.
Thiourea dioxide must also be kept in ambient, and dry conditions.
Thiourea dioxide, an oxidation product of thiourea, is a reducing agent which is stable both in solid form and in cold aqueous solution.
Thiourea dioxide has a slight acidic reaction, and acquires full reducing power only when heated in aqueous solution to about 100°C.
A white or light-yellow odorless crystalline powder.
Mp:126°C.
Soluble in water (27 g / L at room temperature).
Decomposes exothermically at temperatures above 126°C with the emission of noxious gases (sulfur oxides, ammonia, carbon monoxide, nitrogen oxides and hydrogen sulfide) and carbon dioxide.
Extended exposure to temperatures above 50°C and moisture may cause visible decomposition. Irritating to skin and mucous membranes. Corrosive to eye tissue.
Used in leather processing, the paper industry, photographic industry, and in textile processing as a bleaching agent.
Introduction
Thiourea dioxide (TUD), also known as formamidinesulfinic acid (FASA) or aminoiminomethanesulfinic acid (AIMS), is an organosulfur compound with white or pale yellow color; it is an odorless crystalline powder which is stable both in solid form and in cold aqueous solution.
Thiourea dioxide is relatively soluble in water (at 20 ºC, 30 g/L) and insoluble in typical organic solvents and hence can easily be resumed and reused at the end of the reaction.
Thiourea dioxide was first reported by Barnett in 1910.
Thiourea dioxide can be prepared via the oxidation of thiourea by using hydrogen peroxide as an oxidant.
Recently, thiourea dioxide has been used in chemical and industrial processes, as multi-purpose reagent, catalyst, reductant.
Thiourea dioxide is manufactured mainly for use in industrial processes such as discoloring dyes in paper recycling, textile printing and similar processes.
About Thiourea dioxide
Helpful information
Thiourea dioxide is registered under the REACH Regulation and is manufactured in and / or imported to the European Economic Area, at ≥ 1 000 to < 10 000 tonnes per annum.
Thiourea dioxide is used by consumers, in articles, in formulation or re-packing, at industrial sites and in manufacturing.
Consumer Uses
Thiourea dioxide is used in the following products: washing & cleaning products.
Other release to the environment of Thiourea dioxide is likely to occur from: indoor use in close systems with minimal release (e.g. cooling liquids in refrigerators, oil-based electric heaters).
Article service life
Other release to the environment of Thiourea dioxide is likely to occur from: indoor use in long-life materials with low release rate (e.g. flooring, furniture, toys, construction materials, curtains, foot-wear, leather products, paper and cardboard products, electronic equipment). Thiourea dioxide can be found in products with material based on: paper (e.g. tissues, feminine hygiene products, nappies, books, magazines, wallpaper).
Widespread uses by professional workers
ECHA has no public registered data indicating whether or in which chemical products the substance might be used. ECHA has no public registered data on the types of manufacture using Thiourea dioxide.
ECHA has no public registered data on the routes by which Thiourea dioxide is most likely to be released to the environment.
Formulation or re-packing
Thiourea dioxide is used in the following products: coating products, pH regulators and water treatment products, leather treatment products, lubricants and greases, textile treatment products and dyes and fillers, putties, plasters, modelling clay.
Thiourea dioxide has an industrial use resulting in manufacture of another substance (use of intermediates).
Release to the environment of Thiourea dioxide can occur from industrial use: formulation of mixtures and formulation in materials.
Uses at industrial sites
Thiourea dioxide is used in the following products: pH regulators and water treatment products, textile treatment products and dyes, coating products, leather treatment products, lubricants and greases, paper chemicals and dyes, washing & cleaning products and fillers, putties, plasters, modelling clay.
Thiourea dioxide has an industrial use resulting in manufacture of another substance (use of intermediates).
Thiourea dioxide is used in the following areas: formulation of mixtures and/or re-packaging.
Thiourea dioxide is used for the manufacture of: pulp, paper and paper products, textile, leather or fur and chemicals.
Release to the environment of Thiourea dioxide can occur from industrial use: as processing aid, as an intermediate step in further manufacturing of another substance (use of intermediates), in processing aids at industrial sites and in the production of articles.
Manufacture
Release to the environment of Thiourea dioxide can occur from industrial use: manufacturing of the substance.
Thiourea dioxide (CH4N2O2S) is an organosulfur compound that is used as reductive bleaching in the textile industry.
Thiourea dioxide exhibits tautomerism.
Properties
Chemical
Thiourea dioxide can be used to reduce ketones to secondary alcohols.[2]
Physical
Thiourea dioxide is a white solid, poorly soluble in water.
Availability
Thiourea dioxide is sold by lab suppliers.
Preparation
Thiourea dioxide can be easily prepared by the oxidation of thiourea with hydrogen peroxide.
(NH2)2CS + 2 H2O2 → (NH)(NH2)CSO2H + 2 H2O
Chlorine dioxide can also be used.
Projects
Reduction of aromatic nitroaldehydes and nitroketones to nitroalcohols
Thiourea occurs as white, lustrous crystals or flaky solids.
Thiourea dioxide is soluble in water, ammonium thiocyanate solution, and ethanol, and almost insoluble in ether.
Thiourea dioxide is also called formamidine-sulfinic acid or aminoiminomethanesulfinic acid and is often abbreviated as TDO or TUD.
Thiourea dioxide is a powdered stable compound, which dissolves in water and decomposes gradually to produce sulfoxylic acid through formamidine-sulfinic acid to exhibit a reducing action.
Thiourea is a lustrous white crystalline compound and its estimated melting point is 170-180 C and soluble in water and in polar organic solvents; insoluble in non-polar solvents.
Decolorizing the natural color of pigmented fibers, such as cashmere, camel hair, human hair and contaminated dark fibers in white wool, brings about by the following three sequential processes: mordanting, specific rinsing and alkaline hydrogen peroxide bleaching.
Thiourea dioxide (formamidinesulfinic acid or aminoiminomethanesulfinic acid, abbreviated as aimsa) can easily be prepared via the oxidation of thiourea with aqueous solutions of hydrogen peroxide.
Thiourea dioxide (TDO) product is used in leather processing industry, paper, pulp and board industry, photographic industry, textile processing industry, bleaching and reducing agents.
This product is also a component of decolorisation agents.
Thiourea dioxide has been used as a photographic toning agent, in hair preparations, as a dry cleaning agent, in the synthesis of pharmaceuticals and insecticides, in boiler water treatment, and as a reagent for bismuth and selenite ions.
Applications of Thiourea Dioxide
Honorable Discharge: Decolorization of Natural Fabrics
Vat dyes
Indigo Dyeing
Optimized Synthesis of Phosphorothioate Oligodeoxyriboneucliotides substituted with a 5-protected thiol function and a 3 amino group
Material Safety Data Sheet & Product
Thiourea Dioxide
Thiox
Formamidinesulfinic acid
Formamidinesulfinic acid 98+%
Safety Sheet for Thiourea Dioxide
Earthues Thiourea Dioxide
Patent
Thiourea dioxide was applied as a reducing agent during the dyeing of cellulosic fibers with eight commercial sulfur dyes.
The same dyes were also applied to frow dyebaths containing sodium sulfide.
Thiourea dioxide was found that the intensity and fastness properties of the dyeings by both methods were similar, although in some cases slight differences in the shade were observed.
Analysis of the exhausted dyebaths indicates that thiourea dioxide may be considered as a more environmental-friendly substitute for sodium sulfide during the application of sulfur dyes.
Usage : A new environmental-protection agent which can be used in place of sodium hydrosulfite, Thiourea dioxide has better thermal stability and stronger reducing ability.
Operation is simple and effective, and transportation and storage convenient.
There is no pollution associated with the use of thiourea dioxide.
As a promoter used with textiles and dyes, it is widely used to reduce dyes and sulfur dyes, and for bleaching wool and silk.
Other uses include the red uction cleaning of disperse dyes, stripping undesirable colors from dyes, and in dye vat cleaning.
Thiourea dioxide is also used in the paper industry as a bleaching agent and for deinking waste paper.
Other uses:
Thiourea dioxide may be used as catalyst for producing synthetic resins in the polymer materials industry, and also has applications in organic synthesis of photosensitive materials, pharmaceuticals, spices and other fine chemicals, as well as in precious metal recovery and separation.
Properties：
Thiourea Dioxide is an odorless white powder, a stable compound without oxidizability and reducibility.
Solubility in water 26.7g/l at 20℃, saturated aqueous solution pH5.0.
Thiourea Dioxide is very stable even in 20-30℃ aqueous solution, but it decomposes gradually to form sulfinic acid under heat and alkali conditions.
Application：
Thiourea Dioxide is mainly used in dyeing industry, pulp industry, organic synthesis in synthetic fiber industry, as well as an additive in polymerization, stabilizer for polythene, sensitizer of photographical emulsion and so on.
Thiourea Dioxide has the advantages of safe handling and storage, high redox potential and efficiency.
IUPAC names
(E)-amino(imino)methanesulfinic acid
amino(imino) methanesulfinic acid
amino(imino)methanesulfinic acid
AMINOIMINOMETHANESULPHINIC ACID
Aminoiminomethanesulphinic Acid
Aminoiminomethanesulphinic acid
aminoiminomethanesulphinic acid
aminoiminomethanesulphinic acid
Aminoiminomethansulfinsäure
biossido di tiourea
carbamimidoylsulfinic acid
FAS
formamidine sulfinic acid
Formamidinesulfinic Acid
THIOUREA DIOXIDE
Thiourea dioxide
thiourea dioxide
THIOUREA DIOXINE
SYNONYMS
Thiourea dioxide
1758-73-2
Formamidinesulfinic acid
amino(imino)methanesulfinic acid
Formamidine sulfinic acid
Manofast
Thiourea S,S-dioxide
AMINOIMINOMETHANESULFINIC ACID
AIMSA
Aminoiminomethanesulphinic acid
Methanesulfinic acid, aminoimino-
Methenesulfinic acid, aminoimino-
MFCD00002397
NSC 34540
UNII-42BWR07L73
carbamimidoylsulfinic acid
EINECS 217-157-8
NSC 226979
Methanesulfinic acid, 1-amino-1-imino-
42BWR07L73
Formamidinesulfinic acid (Thiourea dioxide)
Formamidinesulfinic acid, 99%
Thiourea, S,S-dioxide
CH4N2O2S
Sulfinoformamidine
PubChem18093
dexamethasoneisonicotinate
DSSTox_CID_9224
EC 217-157-8
DSSTox_RID_78718
DSSTox_GSID_29224
SCHEMBL42684
Urea, thio-, 2,2-dioxide
DTXSID4029224
Formamidinesulfinic acid, >=98%
NSC34540
EINECS 224-065-1
Tox21_200647
BBL011111
NSC-34540
NSC226979
STK802362
ZINC94437827
AKOS005622655
azanyl(azanylidene)methanesulfinic acid
MCULE-7034022108
NE1019
NSC-226979
BRN 1902754
NCGC00248780-01
NCGC00258201-01
AS-12131
CAS-1758-73-2
F0115
FT-0626528
A812126
J-011147
Q7784714
aminoimino-methanesulfinicaci
HONGDA GROUP LIMITED LLC
Amino(imino)
Aminoiminomethanesulfinic acid for synthesis
(4189-44-0) thiourea dioxide
Methanesulfinicacid,aminoimino-
AMIDINOSULFINIC ACID
AMINOIMINOMETHANESULFINIC ACID
AMINOIMINOMETHANESULFINIC ACID THIOUREA DIOXIDE
TNFRSF6 PRIMER PAIR
THIOUREA DIOXIDE
Thiurea dioxide
FAS PRIMER PAIR
FASTECH
FORMAMIDINESULFINIC ACID
FORMAMIDINESULPHINIC ACID
Thiourea Dioxide Formamidine Sulphinic Acid Aminoiminomethanesulfinic acid
FORMAMIDINESULFINIC ACID, 98+%
FORMAMIDINESULFINIC ACID 99%
Sulfocarbamide dioxide
Aminoiminomethanesulphinic acid
Aminoiminomethansulfinsure
Formamidine sulfinate
1,1-Diamino-2-thiaethene2,2-dioxide
Isothiourea 2,2-dioxide
Tiourea dioxide
Formamidinesulfinic acid,99%
Thiourea S,S-dioxide
Methanesulfinic acid, 1-amino-1-imino-
FormamidinesulfinicAcid>
Thiourea dioxide fandachem
Thiourea dioxide ISO 9001：2015 REACH
