68-11-1 Usage
Description
Mercaptoacetic acid, also known as thioglycolic acid (TGA), is an organic compound containing both a thiol (mercaptan) and a carboxylic acid. It is a colorless liquid with a strong unpleasant odor and is readily oxidized by air to the corresponding disulfide. Mercaptoacetic acid was developed in the 1940s and has a wide range of applications across various industries.
Uses
Used in Chemical Synthesis:
Mercaptoacetic acid is used as a nucleophile in thioglycolysis reactions and as a sulfur transfer agent for sulfonyl chloride synthesis. It serves as an intermediate in the production of various pharmaceuticals, including thiomethoprol (caputril), biotin, thiozinc acid, sodium dithiosuccinate, and cysteine.
Used in Hair Care Industry:
Mercaptoacetic acid is used in the manufacture of thioglycolates, which are commonly used for cold waving and as depilatories. The ammonium and sodium salts are used as curling agents, while the calcium salt is used as a depilatory agent.
Used in Metal Analysis:
Mercaptoacetic acid is used as a sensitive reagent for the determination of metals such as iron, molybdenum, silver, and tin. It forms complexes with metal ions, which have been used for the detection of these metals.
Used in Bacteriology:
Mercaptoacetic acid is used in bacteriology for the preparation of thioglycolate media, which is essential for the growth and study of certain types of bacteria.
Used in Polymer Stabilization:
Mercaptoacetic acid is used as an antioxidant and stabilizer in pharmaceuticals to enhance the stability of the main drug and prolong the validity period of pharmaceutical preparations. It is also used as a stabilizer raw material for polyvinyl chloride and rubber products.
Used in Industrial Applications:
Mercaptoacetic acid is used as an inhibitor of copper sulfide and iron sulfide minerals in beneficiation. It is also used for cleaning and derusting of equipment and rails in the petrochemical industry and the railway sector.
Used in Plastics and Coatings:
Mercaptoacetic acid is used in the synthesis of epoxy resins, catalysts of bisphenol A, and as a basic raw material for synthesizing PVC transparent plastic and organic antimony and organic tin heat stabilizers. It can also be used as a modifier for coatings and fibers, a crystallization nucleating agent in polypropylene processing and molding, and a blanket quickening agent.
Used in Analytical Chemistry:
Mercaptoacetic acid is used as a color developer for the photometric determination of molybdenum, rhenium, and iron, and as a compounding masking agent.
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.
Fire Hazard
Combustible material: may burn but does not ignite readily. When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. Runoff may pollute waterways. Substance may be transported in a molten form.
Safety Profile
Poison by ingestion,
skin contact, intraperitoneal, and
intravenous routes. Moderately toxic by
subcutaneous route. A corrosive irritant to
skin, eyes, and mucous membranes. When
heated to decomposition it emits toxic
fumes of SOx. See also MERCAPTANS and
HYDROGEN SULFIDE.
Potential Exposure
Thioglycolic acid is used to make thioglycolates; in sensitivity tests for iron; in formulations of permanent wave solutions and depilatories; in pharmaceutical manufacture; as a stabilizer in vinyl plastics.
Carcinogenicity
Thioglycolic acid was not mutagenic in a
number of Salmonella typhimurium strains with
or without metabolic activation.
Shipping
UN1940 Thyoglycolic acid, Hazard class: 8; Labels: 8-Corrosive material.
Purification Methods
Mix the acid with an equal volume of *benzene; the *benzene is then distilled off to dehydrate the acid. After heating to 100o to remove most of the *benzene, the residue is distilled under vacuum and stored in sealed ampoules at 3o. [Eshelman et al. Anal Chem 22 844 1960, Beilstein 3 IV 1130.]
Incompatibilities
Compounds of the carboxyl group react with all bases, both inorganic and organic (i.e., amines) releasing substantial heat, water and a salt that may be harmful. Incompatible with arsenic compounds (releases hydrogen cyanide gas), diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides (releasing heat, toxic and possibly flammable gases), thiosulfates and dithionites (releasing hydrogen sulfate and oxides of sulfur). Air, strong oxidizers; bases, active metals, for example, sodium potassium, magnesium, and calcium. Readily oxidized by air. Thermal decomposition causes release of hydrogen sulfide. May attack various metals.
Waste Disposal
Dissolve in flammable solvent and burn in furnace equipped with afterburner and alkaline scrubber.
Check Digit Verification of cas no
The CAS Registry Mumber 68-11-1 includes 5 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 2 digits, 6 and 8 respectively; the second part has 2 digits, 1 and 1 respectively.
Calculate Digit Verification of CAS Registry Number 68-11:
(4*6)+(3*8)+(2*1)+(1*1)=51
51 % 10 = 1
So 68-11-1 is a valid CAS Registry Number.
InChI:InChI=1/C2H4O2S/c3-2(4)1-5/h5H,1H2,(H,3,4)/p-1
68-11-1Relevant articles and documents
Sastry, M. S.,Kulshreshtha, S. K.
, p. 95 - 100 (1989)
A new procedure for thioester deprotection using thioglycolic acid in both homogeneous and heterogeneous phase
Mahler, Graciela,Saiz, Cecilia,Villamil, Valentina
, (2021/07/20)
Classic acetyl thioester protection/deprotection methodologies are widely used in organic synthesis, but deprotection step usually requires harsh conditions not suitable for labile substrates. In this work, a new method for thioester deprotection using a thiotransesterification approach is described. Firstly, thioglycolic acid (TGA) was identified as a good deprotecting reagent in solution. In order to develop a thiol polymer-supported reagent, TGA was anchored to a PEG-based resin through an amide bond (TG-NCO-SH). Both homogeneous and heterogeneous approaches were conveniently carried out at room temperature, in aqueous buffer at pH 8. The mild conditions were suitable for alkyl and phenyl thioesters. Moreover labile thioesters containing thiazolidine and oxazolidine scaffolds, bearing amine, ester and acetal functionalities were also deprotected. The polymer-supported TGA gave better deprotection yields compared to TGA in solution, yields ranging from 61 to 90%. The feasibility of the recovery and reuse of TG-NCO-SH reagent was explored, showing it can be reused at least five times without lossing the activity.
Synthesis of an enantiopure thioester as key substrate for screening the sensitivity of penicillin binding proteins to inhibitors
Simon, Justine F.,Bouillez, André,Frère, Jean-Marie,Luxen, André,Zervosen, Astrid
, p. 22 - 31 (2016/10/31)
The synthesis of the enantiopure thioester (R)-2-(2-benzamidopropanoylthio)acetic acid was developed. After the exploration of several activation methods, reaction conditions were found for the formation of the thioester bond in the presence of propylphosphonic anhydride with high enantioselectivity (ee > 99%). The thioester activity of Penicillin Binding Proteins is helpful in research programs looking for new lead structures to overcome the problem of bacterial resistance.