THIOGLYCOLIC ACID
THIOGLYCOLIC ACID
Thioglycolic acid (TGA or mercaptoacetic acid, CAS 68-11-1) is a high-performance chemical containing mercaptan and carboxylic acid functionalities.
Thioglycolic acid is completely miscible in water and is used in industries and applications as diverse as oil and gas, cosmetics, cleaning, leather processing, metals, fine chemistry and polymerization.
Thioglycolic acid (CAS: 68-11-1) is a chemical compound very present in the cosmetic industry, particularly in depilatory creams and cold perms.
This molecule has also found its use in the petrochemical, agrochemical and pharmaceutical industries.
The organotin derivatives of thioglycolic acid esters (CAS: 68-11-1) are for example used as stabilizers for PVC
Thioglycolic acid forms powerful complexes with metals that give it specific characteristics sought after for the assisted recovery of ore as well as for cleaning and corrosion inhibition.
Mercaptoacetic Acid (Thioglycolic Acid)
TGA is used as a chemical depilatory and is still used as such, especially in salt forms, including calcium thioglycolate and sodium thioglycolate.
TGA is the precursor to ammonium thioglycolate that is used for permanents.
It is also used as an acidity indicator, manufacturing of thioglycolates, and in bacteriology for preparation of thioglycolate media.
In fact thioglycolysis reactions used on condensed tannins to study their structure.
Thioglycolic acid (TGA) is the organic compound HSCH2CO2H.
TGA is often called mercaptoacetic acid (MAA).
It contains both a thiol (mercaptan) and carboxylic acid functional groups.
It is a colorless liquid with a strongly unpleasant odor.
TGA is miscible with polar organic solvents.
Thioglycolic acid is a sulfur-containing carboxylic acid.
It is a conjugate acid of a thioglycolate(1-).
Mercaptoacetic acid acid is a colorless liquid with a strong, typical mercaptan disagreeable odor which is used in cosmetic formulations including permanent wave solutions and depilatories, in pharmaceutical manufacture, and as a stabilizer for vinyl plastics.
A recent use is as a capping or stabilizing agent for Cd/Te quantum microdots (QDs).
It is a member of the thioglycolate chemical class.
Other names for thioglycolic acid include:
Mercaptoacetic acid
Thiovanic acid
Thioglycollic acid
Acetomercaptan
Mercaptoacetate
2-Mercaptoacetic acid
2-Thioglycolic acid
Thioglycolic Acid
CAS 68-11-1; Molecular Formula HSCH2COOH
Thioglycolic acid is a reactive reducing agent: it is readily oxidized on exposure to air. Thioglycolic acid is also a weak acid due to the presence of a carboxylic acid function in the molecule.
Because of its high reactivity, it is incompatible with air, strong oxidizers, bases, active metals such as sodium, potassium, magnesium, and calcium (for examples).
Thioglycolic acid is considered to be a Class IIIB Combustible Liquid, therefore, it is not considered to be flammable.
Description
Thio glycolic acid (TGA) is the organic compound HSCH2CO2H .
It contains both a thiol (mercaptan) and a carboxylic acid.
It is a clear liquid with a strong unpleasant odor.
It is readily oxidized by air to the corresponding disulfide [SCH2CO2H]2.
TGA was developed in the 1940s for use as a chemical depilatory and is still used as such, especially in salt forms, including calcium thioglycolate and sodium thioglycolate.
TGA is the precursor to ammonium thioglycolate that is used for permanents.
TGA and its derivatives break the disulfide bonds in the cortex of hair. One reforms these broken bonds in giving hair a “perm.”
Alternatively and more commonly, the process leads to depilation as is done commonly in leather processing.
It is also used as an acidity indicator, manufacturing of thioglycolates, and in bacteriology for preparation of thioglycolate media.
TGA is also used in the making of tin stabilizers often used in certain polyvinyl chloride products (such as vinyl siding).
TGA, usually as its dianion, forms complexes with metal ions. Such complexes have been used for the detection of iron, molybdenum, silver, and tin.
Thioglycolic acid is used as nucleophile in thioglycolysis reactions used on condensed tannins to study their structure.
Chemical Properties
Thioglycolic acid is a colorless liquid with a strong unpleasant odor like rotten eggs.
Chemical Properties
Thioglycolic acid is also known as mercaptoacetic acid, HSCH2COOH is a colorless liquid with a strong unpleasant odor.
Thioglycolic acid is used as a reagent for metals such as iron, molybdenum, silver, and tin,and in bacteriology.
Uses
Thioglycolic Acid is an organic compound containing both a thiol and a carboxylic acid.
Thioglycolic Acid is a precursor to ammonium thioglycolate, a chemical used for permanents.
Thioglycolic Acid is used in organic synthesis as a nucleophile in thioglycolysis reactions and is used as a S transfer agent for sulfonyl chloride synthesis.
Uses
Sensitive reagent for iron, molybdenum, silver, tin.
With ferric iron a blue color appears, and when an alkali hydroxide is added to a solution contg ferrous salts and thioglycolic acid, a yellow precipitate forms. Used in the manufacture of thioglycolates.
The ammonium and sodium salts of Thioglycolic Acid are commonly used for cold waving and the calcium salt is a depilatory.
The sodium salt of Thioglycolic Acid also is used in bacteriology in the preparation of thioglycolate media.
Uses
Mercaptoacetic acid is used as a reagent formetals analysis; in the manufacture of thioglycolates, pharmaceuticals, and permanentwave solutions; and as a vinyl stabilizer.
General Description
A colorless liquid with an unpleasant odor.
Density 1.325 g / cm3.
Mercaptoacetic acid is used to make permanent wave solutions and depilatories.
Corrosive to metals and tissue.
Air & Water Reactions
Readily oxidized by air. Water soluble.
Reactivity Profile
Mercaptoacetic acid is readily oxidized by air . Reacts readily with other oxidizing agents as well in reactions that may generate toxic gases. Incompatible with diazo and azo compounds, halocarbons, isocyanates, aldehydes, alkali metals, nitrides, hydrides, and other strong reducing agents. Reactions with these materials may generate heat and toxic and flammable gases. May react with acids to liberate hydrogen sulfide. Neutralizes bases in exothermic reactions. Reacts with cyanides, sulfites, nitrites, thiosulfates to generate flammable and toxic gases and heat. Reacts with carbonates and bicarbonates.
Hazard
Toxic by ingestion and inhalation, strong irritant to tissue, eyes, and skin.
Health Hazard
TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
Health Hazard
Mercaptoacetic acid is a highly toxic and ablistering compound. Even a 10% solutionwas lethal to most experimental animals by dermal absorption. The oral LD50 value ofundiluted acid is less than 50 mg/kg (Patty1963). The lethal dose in rabbits by skinabsorption is 300 mg/kg. The acute toxicsymptoms in test animals include weakness,respiratory distress, convulsions, irritation ofthe gastrointestinal tract, and liver damage.
Mercaptoacetic acid is a severe irritant.Contact with eyes can cause conjunctivalinflammation and corneal opacity. Skin contact can result in burns and necrosis.
Thioglycolic acid (TGA or mercaptoacetic acid, CAS 68-11-1) is a high-performance chemical containing mercaptan and carboxylic acid functionalities.
TGA is completely miscible in water and is used in industries and applications as diverse as oil and gas, cosmetics, cleaning, leather processing, metals, fine chemistry and polymerization.
Synonyms: 2-Mercaptoacetic acid; 2-Thioglycolic acid; Acetic acid, mercapto-; Acide thioglycolique [French]; Glycolic acid, 2-thio-; Glycolic acid, thio-; Kyselina merkaptooctova [Czech]; Kyselina thioglykolova [Czech]; Mercaptoacetic acid; Mercaptoessigsaeure; Thioglycolate; Thioglycolic acid; Thioglycollic acid; Thiovanic acid; [ChemIDplus] UN1940
Thioglycolic acid forms powerful complexes with metals that give it specific characteristics sought after for the assisted recovery of ore as well as for cleaning and corrosion inhibition.
Preferred IUPAC name: Sulfanylacetic acid
Other names
2-Sulfanylacetic acid
2-Mercaptoacetic acid
Acetyl mercaptan
Mercaptoacetate
Mercaptoacetic acid
Thioglycolic acid
Thiovanic acid
CAS Number: 68-11-1
Chemical formula: C2H4O2S
Molar mass: 92.11 g·mol−1
Appearance: colorless, clear liquid[3]
Odor: strong, disagreeable
Density: 1.32 g/cm3
Melting point: −16 °C (3 °F; 257 K)
Boiling point: 96 °C (205 °F; 369 K) at 5 mmHg
Solubility in water: miscible
Vapor pressure: 10 mmHg (17.8°C)
Magnetic susceptibility (χ): -50.0·10−6 cm3/mol
TGA is used as a chemical depilatory and is still used as such, especially in salt forms, including calcium thioglycolate and sodium thioglycolate.
TGA is the precursor to ammonium thioglycolate that is used for permanents. TGA and its derivatives break the disulfide bonds in the cortex of hair.
One reforms these broken bonds in giving hair a “perm.” Alternatively and more commonly, the process leads to depilation as is done commonly in leather processing.
It is also used as an acidity indicator, manufacturing of thioglycolates, and in bacteriology for preparation of thioglycolate media.
In fact thioglycolysis reactions used on condensed tannins to study their structure.
Organotin derivatives of thioglycolic acid isooctyl esters are widely used as stabilizers for PVC.
These species have the formula R2Sn(SCH2CO2C8H17)2.
Applying TGA can soften nails and then fix pincer nails in the correct position.
Sodium thioglycolate is a component of a special bacterial growth media : thioglycolate broth.
It is also used in so-called “fallout remover” or “wheel cleaner” to remove iron oxide residue from rims.
Ferrous iron combines with thioglycolate to form red-violet ferric thioglycolate.
Production
Thioglycolic acid is prepared by reaction of sodium or potassium chloracetate with alkali metal hydrosulfide in aqueous medium.
It can be also prepared via the Bunte salt obtained by reaction of sodium thiosulfate with chloroacetic acid
mercaptoacetic acid
thioglycolic acid
68-11-1
2-Thioglycolic acid
Acetic acid, mercapto-
Sulfanylacetic acid
2-Mercaptoacetic acid
Thioglycollic acid
Thiovanic acid
2-sulfanylacetic acid
Mercaptoessigsaeure
Glycolic acid, thio-
thioglycolate
Acide thioglycolique
Glycolic acid, 2-thio-
Mercaptoethanoic acid
Acetic acid, 2-mercapto-
USAF CB-35
2-Mercaptoacetate
mercapto acetic acid
Kyselina thioglykolova
Kyselina merkaptooctova
thioglycolicacid
Thioglykolsaeure
alpha-Mercaptoacetic acid
Thioglycolic acid solution
Merkaptoessigsaeure
NSC 1894
.alpha.-Mercaptoacetic acid
Acide thioglycolique [French]
mercapto-acetic acid
UNII-7857H94KHM
Kyselina thioglykolova [Czech]
CCRIS 4873
Kyselina merkaptooctova [Czech]
HSDB 2702
EINECS 200-677-4
UN1940
BRN 0506166
AI3-24151
CHEMBL116455
CHEBI:30065
7857H94KHM
NSC-1894
MFCD00004876
mercaptoacetic acid (thioglycolic acid)
DSSTox_CID_6141
Mercaptoacetic acid, 98%
DSSTox_RID_78033
DSSTox_GSID_26141
CAS-68-11-1
mercaptoactic acid
2-mercaptoaceticacid
Sulfanylacetic acid #
At temperatures above 70°C – common temperatures in well bores, TGA is more efficient than classic ferric ion chelating agents (citric acid, acetic acid, EDTA, NTA).
Moreover, TGA is more efficient than classic ferric reducing agents, such as erythorbic acid or ascorbic acid.
TGA reduces Fe3+ (ferric) ions to chelated Fe2+ (ferrous) ions that remain in solution at pH < 7.5
TGA is stable and efficient at low pH (TGA rapidly reduces high quantities of Fe3+)
TGA can control very high concentrations of ferric iron – up to about 10%
TGA in Corrsion Inhibition Formulation
Water is present in most crude oil and gas production and is the cause of problems in the recovery and transportation of oil and gas. Water can come either from the formation itself or from the water flooding used in the secondary recovery operations. Corrosion is mainly due to the presence of water with CO and/or H2S.
Corrosion inhibitors could be added to form a film which protects the metal from iron corrosion. Corrosion inhibitors are injected either continuously into the fluid stream or into a producing well. They can be added in the water flooding operations of secondary oil recovery, as well as pipelines, transmission lines and refinery units. Although the corrosion inhibition is a complex process, highly dependent of various parameters such as the nature of the inhibitor, fluid composition, pH, temperature, etc., the mechanism generally involves the anchoring of the inhibitor and the formation of a protective film.
A variety of corrosion inhibitors are known, particularly nitrogen-containing compounds such as a morpholine, cyclohexylamine or imidazoline. However, the sulfur-containing compounds can be also effective especially at elevated temperatures. With its unique properties (fast adsorption onto mild steel surfaces, strong chelant), TGA provides good inhibition even in concentrations as low as 5-10 ppm.
TGA for Stimulation
Well stimulation increases the rate at which hydrocarbons will flow out of the reservoir rock into the well. The flow is governed by the permeability and porosity of the rock.
Acidizing is mostly used in limestone (CaCO3) and dolomite formations. Acidizing consists of acid injection into the formation to dissolve rock, which creates large pores allowing the restoration or increase of the flow in the formation. Strong reducing and chelating agents are necessary to avoid precipitation of Fe3+ compounds as they can cause damage (gelatinous precipitates of ferric hydroxide, asphaltic products).
TGA for Oil and Gas Production
Specialty chemicals are now taking an important role in the enhancement of oil recovery and production at different stages:
Well Drilling
Drilling fluids are used to lubricate the drill bit, to control the formation pressure, and to remove formation cuttings. Chemicals can be incorporated into the drilling fluids to create specific effects (foaming, viscosity control).
Cementing and Stimulation
Specific chemicals are used to cement steel pipes and to encourage the flow of crude oil to the well (stimulation).
Oil Production
Chemicals are used at all stages, from oil production at the well bore to the delivery of crude oil at the refinery: as corrosion and scale inhibitors, biocides, and demulsifiers.
Due to its mercaptan functional group, thioglycolic acid and its salts provide essential properties in a wide range of applications:
Industry Applications
TGA is a very effective chain transfer agent for emulsion polymerizations in aqueous media, in particular for acrylic acid and acrylates.
The total miscibility of TGA with water is a benefit in this application.
Polymerization
Petrochemical
Cosmetics
The Bronsted acid characteristics of thioglycolic acid and its thiol functionality make it a chemical of choice for the preparation or regeneration of metal catalysts for hydrodesulfurization.
The salts of thioglycolic acid are used to formulate hair treatments, specialty hair styling products, and in the preparation of depilatory creams.
The main salts are ammonium, calcium and potassium thioglycolate or its disulfide salts.
In some formulations, glyceryl monothioglycolate is also used.
Alkaline sodium thioglycolate is used in removal of hair from leather hides.
It minimizes wastewater treatment costs as compared to the more toxic and harmful sodium hydrosulfide.
Leather Processing
Metals Recovery
Cleaning Formulations
TGA derivatives are also used as depressants in flotation processes for separating valuable metals from ores in mining operations.
TGA derivatives are a safer alternative to the more traditional sodium sulfhydrate (NaSH), particularly in mining environments.
Fine Chemicals
Thioglycolic acid is used for the preparation of pesticides such as thifensulfuron herbicide, or for polythiols or thio-esters.
Due to their ability to complex with metals, thioglycolic acid and thioglycolic acid salts are excellent additives in cleaning solutions, in particular for automotive applications including automotive wheel rim cleaners.
In the catalytic cracking of hydrocarbons for petroleum refining, mercaptides of thioglycolic acid are effectively used as a heavy metal passivator that counteracts the adverse effects of metal (Ni, V, Fe) contaminants on catalysts.
ATAMAN offers distilled thioglycolic acid (TGA) with a minimum purity of 99%, as well as an aqueous 80% solution that offers longer shelf life.
200-677-4 [EINECS]
2-Mercaptoacetic acid
2-mercaptoethanoic acid
2-thioglycolic acid
506166 [Beilstein]
68-11-1 [RN]
Acetic acid, 2-mercapto- [ACD/Index Name]
acetic acid, mercapto-
acetyl mercaptan
Acide sulfanylacétique [French] [ACD/IUPAC Name]
Acide thioglycolique [French]
Glycolic acid, 2-thio-
Glycolic acid, thio-
Kyselina merkaptooctová [Czech]
Kyselina thioglykolová [Czech]
mercaptoacetic acid
Mercaptoessigsaeure [German]
mercaptoethanoic acid
Merkaptoessigsaeure [German]
MFCD00004876 [MDL number]
Sulfanylacetic acid [ACD/IUPAC Name]
Sulfanylessigsäure [German] [ACD/IUPAC Name]
Thioglycolic acid [Wiki]
thioglycolic acid-
Thioglycolicacid
thioglycollic acid
Thioglykolsaeure [German]
α-mercaptoacetic acid
2-sulfanylacetic acid
2-sulfanylethanoic acid
368-11-1
Acetic acid [ACD/Index Name] [ACD/IUPAC Name] [Wiki]
Acide thioglycolique
Acide thioglycolique [French]
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:30065
Kyselina merkaptooctova [Czech]
Kyselina thioglykolova [Czech]
mercapto acetic acid
METHYLTHIO, CARBOXY-
SH1VQ [WLN]
sJPhLPDIKTp@
STR00166
Thiovanic acid
WLN: SH1VQ
α-mercaptoacetic acid
α-Mercaptoacetic acid
巯基乙酸 [Chinese]
acetic acid, 2-mercapto-
acetic acid, mercapto-
glycolic acid, 2-thio-
glycolic acid, thio-
mercaptoacetic acid
2- mercaptoacetic acid
alpha- mercaptoacetic acid
mercaptoethanoic acid
2- mercaptoethanoic acid
sulfanylacetic acid
2- sulfanylacetic acid
2- thioglycolic acid
thioglycolic acid-
thioglycollic acid
thiovanic acid
2-mercaptoacetic acid
2-thioglycolic acid
α-mercaptoacetic acid
Mercaptoacetic acid
Mercaptoessigsäure
Mercaptoethanoic acid
Merkaptoessigsäure
SULFANYLACETIC ACID
Thioglycolic acid
Thioglykolsäure
Thioglycolic acid (TGA, also known as MERCAPTOACETIC ACID) is widely used in the hairdressing industry, which mostly caters to women. TGA has been reported to impair several organs, especially reproductive ones such as testes and ovaries. Thioglycolates (the salt forms of TGA) was shown to penetrate the skin and distribute to the kidneys, lungs, small intestine, and spleen; excretion is primarily in the urine. In addition, thioglycolates can be skin irritants of an animal and can be sensitizers.
CAS number
68-11-1, 7659-86-1
Chemical name
2-Mercaptoacetic Acid; 2-Mercaptoethanoic Acid; 2-Thioglycolic Acid; Glycolic Acid, 2-thio-;, 2-EHTG; OCTYL THIOGLYCOLATE; 2-ethvlhexvlthioglvcolate;2-ETHYLHEXYL THIOGLYCOLATE;Ethylhexyl mercaptoacetate;2-Ethylhexylmercaptoacetat;2-ETHYLHEXYL MERCAPTOACETATE;THIOGLYCOLIC ACID OCTYL ESTER;2-(ETHYLHEXYL) THIOGLYCOLATE;acetic acid, mercapto-, 2-ehylhexyl ester
Common name
TGA, 2-EHTG, 2-EHMA
Thioglycolic acid IN CORROSION INHIBITION FORMULATIONS Water is present in most crude oil and gas production and is the cause of problems in the recovery and transportation of oil and gas. Water can come either from the formation itself or from the water flooding used in the secondary recovery operations. Corrosion is mainly due to the presence of water with CO and/or H2S. Corrosion inhibitors could be added to form a film which protects the metal from iron corrosion. Corrosion inhibitors are injected either continuously into the fluid stream or into a producing well. They can be added in the water flooding operations of secondary oil recovery, as well as pipelines, transmission lines and refinery units. Although the corrosion inhibition is a complex process, highly dependent of various parameters such as the nature of the inhibitor, fluid composition, pH, temperature, etc., the mechanism generally involves the anchoring of the inhibitor and the formation of a protective film. A variety of corrosion inhibitors are known, particularly nitrogen-containing compounds such as a morpholine, cyclohexylamine or imidazoline. However, the sulfur-containing compounds can also be effective especially at elevated temperatures. With its unique properties (fast adsorption onto mild steel surfaces, strong chelant), TGA provides good inhibition even in concentrations as low as 5-10 ppm.
Thioglycolic acid FOR STIMULATION Well stimulation increases the rate at which hydrocarbons will flow out of the reservoir rock into the well. The flow is governed by the permeability and porosity of the rock. Acidizing is mostly used in limestone (CaCO3) and dolomite formations. Acidizing consists of acid injection into the formation to dissolve rock, which creates large pores allowing the restoration or increase of the flow in the formation. Strong reducing and chelating agents are necessary to avoid precipitation of Fe3+ compounds as they can cause damage (gelatinous precipitates of ferric hydroxide, asphaltic products). KEY BENEFITS OF TGA At temperatures above 70°C – common temperatures in well bores – TGA is more efficient than classic ferric ion chelating agents (citric acid, acetic acid, EDTA, NTA). Moreover, TGA is more efficient than classic ferric reducing agents, such as erythorbic acid or ascorbic acid. • TGA reduces Fe3+ (ferric) ions to chelated Fe2+ (ferrous) ions that remain in solution at pH < 7.5 • TGA is stable and efficient at low pH (TGA rapidly reduces high quantities of Fe3+) • TGA can control very high concentrations of ferric iron – up to about 10%.
INDUSTRY APPLICATIONS Due to its mercaptan functional group, thioglycolic acid and its salts provide essential properties in a wide range of applications: Polymerization: TGA is a very effective chain transfer agent for emulsion polymerizations in aqueous media, in particular for acrylic acid and acrylates. The total miscibility of TGA with water is a benefit in this application. Petrochemical: The Bronsted acid characteristics of thioglycolic acid and its thiol functionality make it a chemical of choice for the preparation or regeneration of metal catalysts for hydrodesulfurization. Cosmetics: The salts of thioglycolic acid are used to formulate hair treatments, specialty hair styling products, and in the preparation of depilatory creams. The main salts are ammonium, calcium and potassium thioglycolate or its disulfide salts. In some formulations, glyceryl monothioglycolate is also used. Leather Processing: Alkaline sodium thioglycolate is used in removal of hair from leather hides. It minimizes wastewater treatment costs as compared to the more toxic and harmful sodium hydrosulfide.
Metals Recovery: TGA derivatives are also used as depressants in flotation processes for separating valuable metals from ores in mining operations. TGA derivatives are a safer alternative to the more traditional sodium sulfhydrate (NaSH), particularly in mining environments. Cleaning Formulations: Due to their ability to form complexes with metals, thioglycolic acid and thioglycolic acid salts are excellent additives in cleaning solutions, in particular for automotive applications including automotive wheel rim cleaners. Fine Chemicals: Thioglycolic acid is used for the preparation of pesticides such as thifensulfuron herbicide, or for polythiols or thio-esters. Petroleum Refining: In the catalytic cracking of hydrocarbons for petroleum refining, mercaptides of thioglycolic acid are effectively used as a heavy metal passivator that counteracts the adverse effects of metal (Ni, V, Fe) contaminants on catalysts.
At temperatures above 70°C – common temperatures in well bores, TGA is more efficient than classic ferric ion chelating agents (citric acid, acetic acid, EDTA, NTA). Moreover, TGA is more efficient than classic ferric reducing agents, such as erythorbic acid or ascorbic acid.
• Thioglycolic acid reduces Fe3+ (ferric) ions to chelated Fe2+ (ferrous) ions that remain in solution at pH < 7.5
• Thioglycolic acid is stable and efficient at low pH (TGA rapidly reduces high quantities of Fe3+)
• Thioglycolic acid can control very high concentrations of ferric iron – up to about 10%.
Thioglycolic acid in Corrsion Inhibition Formulation
Water is present in most crude oil and gas production and is the cause of problems in the recovery and transportation of oil and gas.
Water can come either from the formation itself or from the water flooding used in the secondary recovery operations.
Corrosion is mainly due to the presence of water with CO and/or H2S.
Corrosion inhibitors could be added to form a film which protects the metal from iron corrosion.
Corrosion inhibitors are injected either continuously into the fluid stream or into a producing well.
They can be added in the water flooding operations of secondary oil recovery, as well as pipelines, transmission lines and refinery units.
Although the corrosion inhibition is a complex process, highly dependent of various parameters such as the nature of the inhibitor, fluid composition, pH, temperature, etc., the mechanism generally involves the anchoring of the inhibitor and the formation of a protective film.
A variety of corrosion inhibitors are known, particularly nitrogen-containing compounds such as a morpholine, cyclohexylamine or imidazoline.
However, the sulfur-containing compounds can be also effective especially at elevated temperatures.
With its unique properties (fast adsorption onto mild steel surfaces, strong chelant), TGA provides good inhibition even in concentrations as low as 5-10 ppm.
Thioglycolic acid for Stimulation
Well stimulation increases the rate at which hydrocarbons will flow out of the reservoir rock into the well.
The flow is governed by the permeability and porosity of the rock.
Acidizing is mostly used in limestone (CaCO3) and dolomite formations.
Acidizing consists of acid injection into the formation to dissolve rock, which creates large pores allowing the restoration or increase of the flow in the formation.
Strong reducing and chelating agents are necessary to avoid precipitation of Fe3+ compounds as they can cause damage (gelatinous precipitates of ferric hydroxide, asphaltic products).
Thioglycolic acid for Oil and Gas Production
Specialty chemicals are now taking an important role in the enhancement of oil recovery and production at different stages:
Well Drilling
Drilling fluids are used to lubricate the drill bit, to control the formation pressure, and to remove formation cuttings.
Chemicals can be incorporated into the drilling fluids to create specific effects (foaming, viscosity control).
Cementing and Stimulation
Specific chemicals are used to cement steel pipes and to encourage the flow of crude oil to the well (stimulation).
Oil Production
Chemicals are used at all stages, from oil production at the well bore to the delivery of crude oil at the refinery: as corrosion and scale inhibitors, biocides, and demulsifiers.
Due to its mercaptan functional group, thioglycolic acid and its salts provide essential properties in a wide range of applications:
Industry Applications
Thioglycolic acid is a very effective chain transfer agent for emulsion polymerizations in aqueous media, in particular for acrylic acid and acrylates.
The total miscibility of TGA with water is a benefit in this application.
Polymerization
Petrochemical
Cosmetics
The Bronsted acid characteristics of thioglycolic acid and its thiol functionality make it a chemical of choice for the preparation or regeneration of metal catalysts for hydrodesulfurization.
The salts of thioglycolic acid are used to formulate hair treatments, specialty hair styling products, and in the preparation of depilatory creams.
The main salts are ammonium, calcium and potassium thioglycolate or its disulfide salts.
In some formulations, glyceryl monothioglycolate is also used.
Alkaline sodium thioglycolate is used in removal of hair from leather hides.
It minimizes wastewater treatment costs as compared to the more toxic and harmful sodium hydrosulfide.
Leather Processing
Metals Recovery
Cleaning Formulations
Thioglycolic acid derivatives are also used as depressants in flotation processes for separating valuable metals from ores in mining operations.
Thioglycolic acid derivatives are a safer alternative to the more traditional sodium sulfhydrate (NaSH), particularly in mining environments.
Fine Chemicals
Thioglycolic acid is used for the preparation of pesticides such as thifensulfuron herbicide, or for polythiols or thio-esters.
Due to their ability to complex with metals, thioglycolic acid and thioglycolic acid salts are excellent additives in cleaning solutions, in particular for automotive applications including automotive wheel rim cleaners.
In the catalytic cracking of hydrocarbons for petroleum refining, mercaptides of thioglycolic acid are effectively used as a heavy metal passivator that counteracts the adverse effects of metal (Ni, V, Fe) contaminants on catalysts.
• Mercaptoacetic acid
• Acetyl mercaptan
• Mercaptoacetate
• 2-Thioglycolic acid
• 2-Mercaptoacetic acid
Thioglycolic acid, a simple sulfur group- chained carboxylic acid, is a clear liquid melts at -16. c, boils at 96 C soluble in water.
It is an useful chemical intermediate in the chemical reactions such as addition, elimination and cyclization.
Sulfur group will react with bases, acids, ketones and organic halogen compounds, whereas the carboxylic group will preferentially react In the presence of alcohols or amines.
The applications of thioglycolic acid and its derivatives are wide in the fields of PVC stabilizers, down-hole acidizing, corrosion inhibition in the oil field industry, manufacturing of pharmaceuticals, agrochemicals and dyes, shrink-resistant treatment of wool, fabric dying, leather processing.
Thioglycolates are used in cosmetic hair-care products especially permanent waving products as they weaken the keratin structure by the opening of the cystine disulfide linkages.
In addition to hair-waving application, they are used as depilating agents to remove unwanted body hair.
The break-down of disulfide bonds in the cortex by thioglycolates either rearranges (permanent waving) or entirely destroys (depilating) hair structure.
As an antioxidant application in cosmetics, thioglycolates protect the product itself not the skin against oxidative reactions promoted by ultraviolet radiation or oxygen.
Mercaptoacetic Acid (Thioglycolic Acid)
TGA is used as a chemical depilatory and is still used as such, especially in salt forms, including calcium thioglycolate and sodium thioglycolate.
TGA is the precursor to ammonium thioglycolate that is used for permanents.
It is also used as an acidity indicator, manufacturing of thioglycolates, and in bacteriology for preparation of thioglycolate media.
In fact thioglycolysis reactions used on condensed tannins to study their structure.