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Preferred IUPAC name Sodium 2-hydroxyethane-1-sulfonate | |
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3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.014.858 |
PubChem CID | |
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CompTox Dashboard (EPA) | |
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Properties | |
Melting point | 191 to 194 °C (376 to 381 °F; 464 to 467 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Sodium 2-hydroxyethyl sulfonate (also: sodium isethionate) is the sodium salt of 2-hydroxyethane sulfonic acid (isethionic acid), it is used as a hydrophilic head group in washing-active surfactants, known as isethionates (acyloxyethanesulfonates) due to its strong polarity and resistance to multivalent ions. It is being studied as a high production volume chemical in the "High Production Volume (HPV) Chemical Challenge Program" of the US Environmental Protection Agency (EPA). [1]
Sodium 2-hydroxyethyl sulfonate is formed by the reaction of ethylene oxide with sodium hydrogen sulfite in aqueous solution:
To avoid contamination and suppress the formation of by-products (which are difficult to remove) the reaction must be performed under careful control of mass ratios and process conditions. [2] Excess sulfite (SO32−) or bisulfite (HSO3−) lead to an unpleasant odor of the downstream product, higher levels of ethylene glycol or glycol ethers (formed by the hydrolysis and ethoxylation of ethylene oxide) give hygroscopic and greasy surfactants. Concentrated ethylene glycol-containing sodium 2-hydroxyethyl sulfonate solutions can subsequently mostly be freed from ethylene glycol by continuous extraction with e.g. isopropanol (<0.5%). [3] Therefore, in the continuous industrial process an aqueous sodium hydrogen sulfite solution is prepared in a first reactor by mixing a sodium hydroxide solution and sulfur dioxide. In a second reactor the sodium hydrogen sulfite solution is mixed with a slight excess of ethylene oxide to obtain sodium 2-hydroxyethyl sulfonate in almost quantitative yields at elevated temperature and pressure with a precise control of pH. The reaction has to take place under the exclusion of oxygen and under precise control of the stoichiometry of the reactants, the temperature, the pH and the throughput.
Solid sodium 2-hydroxyethyl sulfonate is a colorless, free-flowing, non-hygroscopic solid, which dissolves readily in water and has good biodegradability. Due to the method of synthesis samples often contain traces of sodium sulfite or sodium hydrogen sulfite causing aqueous solution to possesses a mildly alkaline pH of about 10. [4]
The main use of sodium 2-hydroxyethyl sulfonate is the production of the isethionate class of surfactants. These are readily foaming and particularly mild, making them suitable for cleaning sensitive skin and are therefore mainly used in baby soaps and shampoos. [5] Because of its pronounced skin compatibility sodium 2-hydroxyethyl sulfonate is added to soaps and liquid skin cleansers with up to 15 parts by weight.
From sodium 2-hydroxyethyl sulfonate the so-called biological buffers such as HEPES, MES, PIPES etc. are easily accessible. [6]
The addition of 2-hydroxyethyl sulfonate to electroplating baths allows higher current densities and lower concentrations than the much more expensive methane sulphonic acid with improved appearance. [7]
In chemistry and manufacturing, electrolysis is a technique that uses direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. The voltage that is needed for electrolysis to occur is called the decomposition potential. The word "lysis" means to separate or break, so in terms, electrolysis would mean "breakdown via electricity."
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na+ and hydroxide anions OH−.
Petrochemicals are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.
Surfactants are chemical compounds that decrease the surface tension or interfacial tension between two liquids, a liquid and a gas, or a liquid and a solid. The word "surfactant" is a blend of surface-active agent, coined in 1950. As they consist of a water-repellent and a water-attracting part, they enable water and oil to mix; they can form foam and facilitate the detachment of dirt.
Polyethylene glycol (PEG; ) is a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine. PEG is also known as polyethylene oxide (PEO) or polyoxyethylene (POE), depending on its molecular weight. The structure of PEG is commonly expressed as H−(O−CH2−CH2)n−OH.
Ethylene oxide is an organic compound with the formula C2H4O. It is a cyclic ether and the simplest epoxide: a three-membered ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless and flammable gas with a faintly sweet odor. Because it is a strained ring, ethylene oxide easily participates in a number of addition reactions that result in ring-opening. Ethylene oxide is isomeric with acetaldehyde and with vinyl alcohol. Ethylene oxide is industrially produced by oxidation of ethylene in the presence of a silver catalyst.
N-Methylethanolamine is an alkanolamine with the formula CH3NHCH2CH2OH. It is flammable, corrosive, colorless, viscous liquid. It is an intermediate in the biosynthesis of choline.
Nafion is a brand name for a sulfonated tetrafluoroethylene based fluoropolymer-copolymer synthesized in 1962 by Dr. Donald J. Connolly at the DuPont Experimental Station in Wilmington Delaware. Additional work on the polymer family was performed in the late 1960s by Dr. Walther Grot of DuPont. Nafion is a brand of the Chemours company. It is the first of a class of synthetic polymers with ionic properties that are called ionomers. Nafion's unique ionic properties are a result of incorporating perfluorovinyl ether groups terminated with sulfonate groups onto a tetrafluoroethylene (PTFE) backbone. Nafion has received a considerable amount of attention as a proton conductor for proton exchange membrane (PEM) fuel cells because of its excellent chemical and mechanical stability in the harsh conditions of this application.
In organic chemistry, ethoxylation is a chemical reaction in which ethylene oxide adds to a substrate. It is the most widely practiced alkoxylation, which involves the addition of epoxides to substrates.
In organic chemistry, sulfonic acid refers to a member of the class of organosulfur compounds with the general formula R−S(=O)2−OH, where R is an organic alkyl or aryl group and the S(=O)2(OH) group a sulfonyl hydroxide. As a substituent, it is known as a sulfo group. A sulfonic acid can be thought of as sulfuric acid with one hydroxyl group replaced by an organic substituent. The parent compound is the parent sulfonic acid, HS(=O)2(OH), a tautomer of sulfurous acid, S(=O)(OH)2. Salts or esters of sulfonic acids are called sulfonates.
Isethionic acid is an organosulfur compound containing an alkylsulfonic acid located beta to a hydroxy group. Its discovery is generally attributed to Heinrich Gustav Magnus, who prepared it by the action of solid sulfur trioxide on ethanol in 1833. It is a white water-soluble solid used in the manufacture of certain surfactants and in the industrial production of taurine. It is most commonly available in the form of its sodium salt.
Lignosulfonates (LS) are water-soluble anionic polyelectrolyte polymers: they are byproducts from the production of wood pulp using sulfite pulping. Most delignification in sulfite pulping involves acidic cleavage of ether bonds, which connect many of the constituents of lignin. Sulfonated lignin (SL) refers to other forms of lignin by-product, such as those derived from the much more popular Kraft process, that have been processed to add sulfonic acid groups. The two have similar uses and are commonly confused with each other, with SL being much cheaper. LS and SL both appear as free-flowing powders; the former is light brown while the latter is dark brown.
2-Acrylamido-2-methylpropane sulfonic acid (AMPS) was a Trademark name by The Lubrizol Corporation. It is a reactive, hydrophilic, sulfonic acid acrylic monomer used to alter the chemical properties of wide variety of anionic polymers. In the 1970s, the earliest patents using this monomer were filed for acrylic fiber manufacturing. Today, there are over several thousands patents and publications involving use of AMPS in many areas including water treatment, oil field, construction chemicals, hydrogels for medical applications, personal care products, emulsion coatings, adhesives, and rheology modifiers. Lubrizol discontinued the production of this monomer in 2017 due to copy-cat production from China and India destroying the profitability of this product.
Vinylsulfonic acid is the organosulfur compound with the chemical formula CH2=CHSO3H. It is the simplest unsaturated sulfonic acid. The C=C double bond is a site of high reactivity. Polymerization gives polyvinylsulfonic acid, especially when used as a comonomer with functionalized vinyl and (meth)acrylic acid compounds. It is a colorless, water-soluble liquid, although commercial samples can appear yellow or even red.
N-Oleoylsarcosine (Sarkosyl O) is an amphiphilic oleic acid derivative having a sarcosine head group (N-methylglycine) which is used as a water-in-oil emulsifier and corrosion inhibitor.
The Criegee oxidation is a glycol cleavage reaction in which vicinal diols are oxidized to form ketones and aldehydes using lead tetraacetate. It is analogous to the use of periodate but uses a milder oxidant. This oxidation was discovered by Rudolf Criegee and coworkers and first reported in 1931 using ethylene glycol as the substrate.
1,4-butane sultone is a six-membered δ-sultone and the cyclic ester of 4-hydroxybutanesulfonic acid. As a sulfo-alkylating agent, 1,4-butanesultone is used to introduce the sulfobutyl group (–(CH2)4–SO3−) into hydrophobic compounds possessing nucleophilic functional groups, for example hydroxy groups (as in the case of β-cyclodextrin) or amino groups (as in the case of polymethine dyes). In such, the sulfobutyl group is present as neutral sodium salt and considerably increases the water solubility of the derivatives.
Taurates (or taurides) are a group of mild anionic surfactants. They are composed of a hydrophilic head group, consisting of N-methyltaurine (2-methylaminoethanesulfonic acid) and a lipophilic residue, consisting of a long-chain carboxylic acid (fatty acid), both linked via an amide bond. The fatty acids used could be lauric (C12), myristic (C14), palmitic (C16) or stearic acid (C18), but mainly mixtures of oleic acid (C18:1) and coconut fatty acid (C8 – C18) are used. Besides sodium, no other counterions play a relevant role (these could be e. g. ammonium or other alkali or alkaline earth metals).
N-Methyltaurine is an aminosulfonic acid which is present as a zwitterion in the crystalline state and in polar solvents. In contrast to the widespread taurine, N-methyltaurine has been found in nature only in red algae, where it is formed by methylation of taurine. It is suitable for esterification with long-chain carboxylic acids to taurides (acylaminoethansulfonaten) because of its high polarity and the relatively good solubility of its alkaline earth metal salts, which are also used as mild anionic surfactants.
Choline bitartrate is an organic compound with the chemical formula [(CH3)3NCH2CH2OH]+HOOC−CH(OH)−CH(OH)−COO−. It is a white crystalline powder with an acid taste. It is hygroscopic when exposed to air. Modern texts refer to the choline salt of the natural form of tartaric acid, that is, the salt called choline dextrobitartrate, choline (2R,3R)-bitartrate or choline L-(+)-bitartrate.