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Sulfinic Acid
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 typically more acidic than the corresponding carboxylic acid RCO2H. Sulfur is pyramidal, consequently sulfinic acids are chiral. The free acids are typically unstable, disproportionating to the sulfonic acid RSO3H and thiosulfonate RSSO2R. The formal anhydride of a sulfinic acid has no oxygen atom bridge, but is instead a sulfinyl sulfone (R–S+(–O−)–S2+(–O−)2–), and disproportionation is believed to occur through the free-radical fission of this intermediate. Alkylation of sulfinic acids can give either sulfones or sulfinate esters, depending on the solvent and reagent. Strongly polarized reactants (e.g. trimethyloxonium tetrafluoroborate) give esters, whereas relatively unpolarized reactants (e.g. an alkyl halide or enone) give sulfones. Sulfinates react ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt
Cobalt is a chemical element; it has Symbol (chemistry), symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, somewhat brittle, gray metal. Cobalt-based blue pigments (cobalt blue) have been used since antiquity for jewelry and paints, and to impart a distinctive blue tint to glass. The color was long thought to be due to the metal bismuth. Miners had long used the name ''kobold ore'' (German language, German for ''goblin ore'') for some of the blue pigment-producing minerals. They were so named because they were poor in known metals and gave off poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), which was ultimately named for the ''kobold''. Today, some cobalt is produced sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thionyl Chloride
Thionyl chloride is an inorganic compound with the chemical formula . It is a moderately Volatility (chemistry), volatile, colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a Halogenation, chlorinating reagent, with approximately per year being produced during the early 1990s, but is occasionally also used as a solvent. It is toxic, reacts with water, and is also List of Schedule 3 substances (CWC), listed under the Chemical Weapons Convention as it may be used for the production of chemical weapons. Thionyl chloride is sometimes confused with sulfuryl chloride, , but the properties of these compounds differ significantly. Sulfuryl chloride is a source of chlorine whereas thionyl chloride is a source of chloride ions. Production The major industrial synthesis involves the reaction of sulfur trioxide and sulfur dichloride. This synthesis can be adapted to the laboratory by heating oleum to slowly distill the sulfur trioxide into a cooled fla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrophilic Addition
In organic chemistry, an electrophilic addition (AE) reaction is an addition reaction where a chemical compound containing a double or triple bond has a π bond broken, with the formation of two new σ bonds.March, Jerry; (1985). Advanced Organic Chemistry reactions, mechanisms and structure (3rd ed.). New York: John Wiley & Sons, inc. The driving force for this reaction is the formation of an electrophile X+ that forms a covalent bond with an electron-rich, unsaturated C=C bond. The positive charge on X is transferred to the carbon-carbon bond, forming a carbocation during the formation of the C-X bond. : In the second step of an electrophilic addition, the positively charge on the intermediate combines with an electron-rich species to form the second covalent bond. The second step is the same nucleophilic attack process found in an SN1 reaction. The exact nature of the electrophile and the nature of the positively charged intermediate are not always clear and depend on react ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conjugate Addition
Nucleophilic conjugate addition is a type of organic reaction. Ordinary nucleophilic additions or 1,2-nucleophilic additions deal mostly with additions to carbonyl compounds. Simple alkene compounds do not show 1,2 reactivity due to lack of polarity, unless the alkene is activated with special substituents. With α,β-unsaturated carbonyl compounds such as cyclohexenone it can be deduced from resonance structures that the β position is an electrophilic site which can react with a nucleophile. The negative charge in these structures is stored as an alkoxide anion. Such a nucleophilic addition is called a nucleophilic conjugate addition or 1,4-nucleophilic addition. The most important active alkenes are the aforementioned conjugated carbonyls and acrylonitriles. Reaction mechanism Conjugate addition is the vinylogous counterpart of direct nucleophilic addition. A nucleophile reacts with a α,β-unsaturated carbonyl compound in the β position. The negative charge carried by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levulinic Acid
Levulinic acid, or 4-oxopentanoic acid, is an organic compound with the chemical formula, formula CH3C(O)CH2CH2CO2H. It is classified as a keto acid. This white crystalline solid is soluble in water and polar organic solvents. It is derived from degradation of cellulose and is a potential precursor to biofuels, such as ethyl levulinate. Synthesis Levulinic acid was first prepared in 1840 by Dutch chemist Gerardus Johannes Mulder by heating fructose with hydrochloric acid. The first commercial production of levulinic acid began as a batchwise process in an autoclave by starch manufacturer A. E. Staley in the 1940s. In 1953 Quaker Oats developed a continuous process for the production of levulinic acid. In 1956 it was identified as a platform chemical with high potential. and in 2004 the US Department of Energy (U.S. DoE) identified levulinic acid as one of the 12 potential platform chemicals in the biorefinery concept. The synthesis of levulinic acid from hexoses (glucose, fructo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Cyanide
Sodium cyanide is a compound with the formula Na C N and the structure . It is a white, water-soluble solid. Cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in gold mining, also exploits its high reactivity toward metals. It is a moderately strong base. Production and chemical properties Sodium cyanide is produced by treating hydrogen cyanide with sodium hydroxide: : Worldwide production was estimated at 500,000 tons in the year 2006. Formerly it was prepared by the Castner process involving the reaction of sodium amide with carbon at elevated temperatures. : The structure of solid NaCN is related to that of sodium chloride. The anions and cations are each six-coordinate. Potassium cyanide (KCN) adopts a similar structure. When treated with acid, it forms the toxic gas hydrogen cyanide: : Because the salt is derived from a weak acid, sodium cyanide readily reverts to HCN by hydrolysis; the moist solid emits smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophile
In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are Lewis bases. ''Nucleophilic'' describes the affinity of a nucleophile to bond with positively charged Atomic nucleus, atomic nuclei. Nucleophilicity, sometimes referred to as nucleophile strength, refers to a substance's nucleophilic character and is often used to compare the affinity of atoms. Neutral nucleophilic reactions with solvents such as Alcohol (chemistry), alcohols and water are named solvolysis. Nucleophiles may take part in nucleophilic substitution, whereby a nucleophile becomes attracted to a full or partial positive charge, and nucleophilic addition. Nucleophilicity is closely related to basicity. The difference between the two is, that basicity is a thermodynamic property (i.e. relates to an equilibrium state), but nucleop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfone
In organic chemistry, a sulfone is a organosulfur compound containing a sulfonyl () functional group attached to two carbon atoms. The central hexavalent sulfur atom is double-bonded to each of two oxygen atoms and has a single bond to each of two carbon atoms, usually in two separate hydrocarbon substituents. Synthesis and reactions By oxidation of thioethers and sulfoxides Sulfones are typically prepared by organic oxidation of thioethers, often referred to as sulfides. Sulfoxides are intermediates in this route. For example, dimethyl sulfide oxidizes to dimethyl sulfoxide and then to dimethyl sulfone. From SO2 : Sulfur dioxide is a convenient and widely used source of the sulfonyl functional group. Specifically, Sulfur dioxide participates in cycloaddition reactions with dienes. The industrially useful solvent sulfolane is prepared by addition of sulfur dioxide to buta-1,3-diene followed by hydrogenation of the resulting sulfolene. From sulfonyl and sulfuryl halides Sulf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Sulfur Dioxide Complex
In organometallic chemistry, metal sulfur dioxide complexes are complexes that contain sulfur dioxide, , bonded to a transition metal. Such compounds are common but are mainly of theoretical interest. Historically, the study of these compounds has provided insights into the mechanisms of migratory insertion reactions. Bonding modes Sulfur dioxide forms complexes with many transition metals. Most numerous are complexes with metals in oxidation state 0 or +1. In most cases SO2 binds in monodentate fashion, attaching to the metal through sulfur. Such complexes are further subdivided according to the planarity or pyramidalization at sulfur. The various bonding modes are: * η1-SO2, planar (meaning that the MSO2 subunit forms a plane). In such complexes, SO2 is classified as a 2e donor complemented by pi- back bonding into the empty pz orbital localized on sulfur. * η1-SO2, pyramidal (meaning that the MSO2 subunit is pyramidal at sulfur). In such complexes, SO2 is classifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur Dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is released naturally by volcanic activity and is produced as a by-product of metals refining and the burning of Sour gas, sulfur-Sour crude oil, bearing fossil fuels. Sulfur dioxide is somewhat toxic to humans, although only when inhaled in relatively large quantities for a period of several minutes or more. It was known to medieval alchemy, alchemists as "volatile spirit of sulfur". Structure and bonding SO2 is a bent molecule with ''C''2v Point groups in three dimensions, symmetry point group. A valence bond theory approach considering just ''s'' and ''p'' orbitals would describe the bonding in terms of resonance (chemistry), resonance between two resonance structures. The sulfur–oxygen bond has a bond order of 1.5. There is support f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disulfide
In chemistry, a disulfide (or disulphide in British English) is a compound containing a functional group or the anion. The linkage is also called an SS-bond or sometimes a disulfide bridge and usually derived from two thiol groups. In inorganic chemistry, the anion appears in a few rare minerals, but the functional group has tremendous importance in biochemistry. Disulfide bridges formed between thiol groups in two cysteine residues are an important component of the tertiary and quaternary structure of proteins. Compounds of the form are usually called ''persulfides'' instead. Organic disulfides Structure Disulfides have a C–S–S–C dihedral angle approaching 90°. The S–S bond length is 2.03 Å in diphenyl disulfide, similar to that in elemental sulfur. Disulfides are usually symmetric but they can also be unsymmetric. Symmetrical disulfides are compounds of the formula . Most disulfides encountered in organosulfur chemistry are symmetrical disulfides. Unsymme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
