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Sulfinate
Sulfinic acids are oxoacids of sulfur with the structure RSO(OH). In these organosulfur compounds, sulfur is pyramidal. Structure and properties Sulfinic acids RSO2H are about 1000x more acidic than the corresponding carboxylic acid RCO2H. Sulfur is pyramidal, consequently sulfinic acids are chiral. Preparation They are often prepared in situ by acidification of the corresponding sulfinate salts, which are typically more robust than the acid. These salts are generated by reduction of sulfonyl chlorides. An alternative route is the reaction of Grignard reagents with sulfur dioxide. Transition metal sulfinates are also generated by insertion of sulfur dioxide into metal alkyls, a reaction that may proceed via a metal sulfur dioxide complex. Unsubstituted sulfinic acid, when R is the hydrogen atom, is a higher energy isomer of sulfoxylic acid, both of which are unstable. Examples An example of a simple, well-studied sulfinic acid is phenylsulfinic acid. A commercially import ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rongalite
Rongalite is a chemical compound with the molecular formula Na+HOCH2SO2−. This salt has many additional names, including Rongalit, sodium hydroxymethylsulfinate, sodium formaldehyde sulfoxylate, and Bruggolite. It is listed in the European Cosmetics Directive as sodium oxymethylene sulfoxylate ( INCI). It is water-soluble and generally sold as the dihydrate. The compound and its derivatives are widely used in the dye industry.D. Schubart "Sulfinic Acids and Derivatives" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2012, Wiley-VCH, Weinheim. The structure of this salt has been confirmed by X-ray crystallography. Synthesis and reactions Although available commercially, the salt can be prepared from sodium dithionite and formaldehyde: :Na2S2O4 + 2 CH2O + H2O → HO-CH2-SO3Na + HO-CH2-SO2Na This reaction proceeds quantitatively, such that dithionite can be determined by its conversion to Rongalite, which is far less O2-sensitive and thus easier to handle. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfinic Acids
Sulfinic acids are oxoacids of sulfur with the structure RSO(OH). In these organosulfur compounds, sulfur is pyramidal. Structure and properties Sulfinic acids RSO2H are about 1000x more acidic than the corresponding carboxylic acid RCO2H. Sulfur is pyramidal, consequently sulfinic acids are chiral. Preparation They are often prepared in situ by acidification of the corresponding sulfinate salts, which are typically more robust than the acid. These salts are generated by reduction of sulfonyl chlorides. An alternative route is the reaction of Grignard reagents with sulfur dioxide. Transition metal sulfinates are also generated by insertion of sulfur dioxide into metal alkyls, a reaction that may proceed via a metal sulfur dioxide complex. Unsubstituted sulfinic acid, when R is the hydrogen atom, is a higher energy isomer of sulfoxylic acid, both of which are unstable. Examples An example of a simple, well-studied sulfinic acid is phenylsulfinic acid. A commercially import ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organosulfur Compound
Organosulfur compounds are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature abounds with organosulfur compounds—sulfur is vital for life. Of the 20 common amino acids, two ( cysteine and methionine) are organosulfur compounds, and the antibiotics penicillin and sulfa drugs both contain sulfur. While sulfur-containing antibiotics save many lives, sulfur mustard is a deadly chemical warfare agent. Fossil fuels, coal, petroleum, and natural gas, which are derived from ancient organisms, necessarily contain organosulfur compounds, the removal of which is a major focus of oil refineries. Sulfur shares the chalcogen group with oxygen, selenium, and tellurium, and it is expected that organosulfur compounds have similarities with carbon–oxygen, carbon–selenium, and carbon–tellurium compounds. A classical chemical test for the detection of sulfur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cysteine Dioxygenase
Cysteine dioxygenase (CDO) is a non-heme iron enzyme that catalyzes the conversion of L-cysteine to cysteine sulfinic acid (cysteine sulfinate). CDO plays an important role in cysteine catabolism, regulating intracellular levels of cysteine and responding changes in cysteine availability. As such, CDO is highly regulated and undergoes large changes in concentration and efficiency. It oxidizes cysteine to the corresponding sulfinic acid by activation of dioxygen, although the exact mechanism of the reaction is still unclear. In addition to being found in mammals, CDO also exists in some yeast and bacteria, although the exact function is still unknown. CDO has been implicated in various neurodegenerative diseases and cancers, which is likely related to cysteine toxicity. Function CDO is responsible for the first major step in metabolism of cysteine. CDO oxidizes to cysteine sulfinic acid (which exists predominantly in the anionic sulfinate form ''in vivo''). Overall, CDO catalyzes t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfoxylic Acid
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. The complementary base is the sulfoxylate anion which is much more stable. In between these states is the ion, also somewhat stable. Sulfoxylate ions can be made by decomposing thiourea dioxide in an alkaline solution. To do this, thiourea dioxide first forms a tautomer, aminoiminomethanesulfinic acid (H2NC(=NH)SO2H, abbreviated AIMS) which breaks apart. Sulfoxylate reacts with formaldehyde to yield a hydroxymethanesulfinate called rongalite: : + H2CO → which is an important chemical for dyeing. Formation Sulfoxylic acid has been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenylsulfinic Acid
Phenylsulfinic acid is an organosulfur compound with the formula C6H5SO2H. It is a colorless or white crystalline solid that is usually stored in the form of its sodium salt. In aqueous solution it is strongly acidic and is easily oxidized in air. Phenylsulfinic acid and its esters are chiral. Acidity There is a large range of p''K''a values in the literature, with most authors giving a value of around 1.30.a) A. T. Fuller, I. M. Tonkin and J. Walker, J. Chem. Soc., 1945, 636; b) S. Smiles and C. M. Bere, "Organic Syntheses," Coll. Vol. I, ed. by A. H. Blatt, John Wiley and Sons, Inc., New York, 1948, p. 7; c) E. Bader and H. D. Hermann, Chem. Ber., 88, 46 (1955); d) M. Kulka, Can. J. Chem., 32, 601 (1954). This inconsistency can be explained by differences in ionic strength between quoted values. By measuring the p''K''a at various ionic strengths and extrapolating to zero ionic strength, the p''K''a of phenylsulfinic acid was determined to be 2.76. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sultine
In chemistry, a sultine is a cyclic ester of a sulfinic acid. This class of organosulfur compound Organosulfur compounds are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature abounds with organosulfur compounds—sulfur ...s has few applications. These compounds are typically prepared by the dehydration of hydroxy-sulfinic acids or their equivalent. Illustrative of an alternative route, xylylene dibromide reacts with sodium sulfoxylate (source of SO22-) to give the sultine C6H4(CH2S(O)OCH2), which is a precursor to o- quinodimethane.{{cite book, first1=Donald C., last1=Dittmer, first2=Michael D., last2=Hoey , chapter=Cyclic Sulphinic Acid Derivatives (Sultines and Sulphinamides), page = 239-273, year=1981, editor=Saul Patai, title=Sulphinic Acids, Esters and Derivatives, doi=10.1002/9780470772270.ch9, publisher=John Wiley & Sons, series=PATAI'S Chemis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cysteine
Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, sometimes the symbol Cyz is used. The deprotonated form can generally be described by the symbol Cym as well. The thiol is susceptible to oxidation to give the disulfide derivative cystine, which serves an important structural role in many proteins. In this case, the symbol Cyx is sometimes used. When used as a food additive, it has the E number E920. Cysteine is encoded by the codons UGU and UGC. The sulfur-containing amino acids cysteine and methionine are more easily oxidized than the other amino acids. Structure Like other amino acids (not as a residue of a protein), cysteine exists as a zwitterion. Cysteine has chirality in the older / notation based on homology to - and -glyceraldehyde. In the newer ''R''/''S'' system of design ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conjugate Base
A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid donates a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a hydrogen ion. On the other hand, a conjugate base is what is left over after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a species formed by the removal of a proton from an acid, as in the reverse reaction it is able to gain a hydrogen ion. Because some acids are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic. In summary, this can be represented as the following chemical reaction: :acid + base conjugate\ base + conjugate\ acid Johannes Nicolaus Brønsted and Martin Lowry introduced the Brønsted–Lowry theory, which proposed that any compound that can transfer a proton to any other compound is an acid, and the compound that accepts the proton is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use, and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or " high-test peroxide", decomposes explosively when heated and has been used as a propellant in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a stabilizer in a weakly acidic solution in a dark bottle to block light. Hydrogen peroxide is found in biological systems including the human body. Enzymes that use or decompose hydrogen peroxide are classified as peroxidases. Properties The boili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. There are two classes of redox reactions: * ''Electron-transfer'' – Only one (usually) electron flows from the reducing agent to the oxidant. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * ''Atom transfer'' – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidation reactions are commonly associated with the formation of oxides, other chemical species can serve the same function. In hydrogenation, C=C (and other) bon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
