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Xylylene Dibromide
Xylylene dibromide is an organic compound with the formula C6H4(CH2Br)2. It is an off-white solid that, like other benzyl halides, a strong lachrymator. It is a useful reagent owing to the convenient reactivity of the two C-Br bonds. Two other isomers are known, para- and meta-xylylene dibromide. Synthesis It is prepared by the photochemical reaction of ortho-xylene with bromine: :C6H4(CH3)2 + 2Br2 → C6H4(CH2Br)2 + 2 HBr Reactions Further bromination gives the tetrabromide: :C6H4(CH2Br)2 + 2Br2 → C6H4(CHBr2)2 + 2 HBr Upon reaction with thiourea followed by hydrolysis of the intermediate bisisothiouronium salts, xylylene dibromide can be converted to the dithiol C6H4(CH2SH)2. Xylylene dibromide is a precursor to the ephemeral molecule ortho-quinonedimethane, also known as xylylene. This species can be trapped when the dehalogenation is conducted in the presence of iron carbonyl. Coupling of xylylene dibromide by treatment with lithium metal gives dibenzo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzyl Halide
Benzyl chloride, or α-chlorotoluene, is an organic compound with the formula C6H5CH2Cl. This colorless liquid is a reactive organochlorine compound that is a widely used chemical building block. Preparation Benzyl chloride is prepared industrially by the gas-phase photochemical reaction of toluene with chlorine: :C6H5CH3 + Cl2 → C6H5CH2Cl + HCl In this way, approximately 100,000 tonnes are produced annually. The reaction proceeds by the free radical process, involving the intermediacy of free chlorine atoms. Side products of the reaction include benzal chloride and benzotrichloride. Other methods of production exist, such as the Blanc chloromethylation of benzene. Benzyl chloride was first prepared from treatment of benzyl alcohol with hydrochloric acid. Uses and reactions Industrially, benzyl chloride is the precursor to benzyl esters, which are used as plasticizers, flavorants, and perfumes. Phenylacetic acid, a precursor to pharmaceuticals, is produced from benzyl cyani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lachrymator
Tear gas, also known as a lachrymator agent or lachrymator (), sometimes colloquially known as "mace" after the early commercial aerosol, is a chemical weapon that stimulates the nerves of the lacrimal gland in the eye to produce tears. In addition, it can cause severe eye and respiratory pain, skin irritation, bleeding, and blindness. Common lachrymators both currently and formerly used as tear gas include pepper spray (OC gas), PAVA spray (nonivamide), CS gas, CR gas, CN gas (phenacyl chloride), bromoacetone, xylyl bromide and Mace (a branded mixture). While lachrymatory agents are commonly deployed for riot control by law enforcement and military personnel, its use in warfare is prohibited by various international treaties.E.g. the Geneva Protocol of 1925 prohibited the use of "asphyxiating gas, or any other kind of gas, liquids, substances or similar materials". During World War I, increasingly toxic and deadly lachrymatory agents were used. The short and long-term effec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photochemical Reaction
Organic photochemistry encompasses organic reactions that are induced by the action of light. The absorption of ultraviolet light by organic molecules often leads to reactions. In the earliest days, sunlight was employed, while in more modern times ultraviolet lamps are employed. Organic photochemistry has proven to be a very useful synthetic tool. Complex organic products can be obtained simply. History Early examples were often uncovered by the observation of precipitates or color changes from samples that were exposed to sunlights. The first reported case was by Ciamician that sunlight converted santonin to a yellow photoproduct: An early example of a precipitate was the photodimerization of anthracene, characterized by Yulii Fedorovich Fritzsche and confirmed by Elbs. Similar observations focused on the dimerization of cinnamic acid to truxillic acid. Many photodimers are now recognized, e.g. pyrimidine dimer, thiophosgene, diamantane. Another example was uncovered by Egbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromine
Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826), its name was derived from the Ancient Greek (bromos) meaning "stench", referring to its sharp and pungent smell. Elemental bromine is very reactive and thus does not occur as a native element in nature but it occurs in colourless soluble crystalline mineral halide salts, analogous to table salt. In fact, bromine and all the halogens are so reactive that they form bonds in pairs—never in single atoms. While it is rather rare in the Earth's crust, the high solubility of the bromide ion (Br) has caused its accumulation in the oceans. Commercial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiourea
Thiourea () is an organosulfur compound with the formula and the structure . It is structurally similar to urea (), except that the oxygen atom is replaced by a sulfur atom (as implied by the ''thio-'' prefix); however, the properties of urea and thiourea differ significantly. Thiourea is a reagent in organic synthesis. "Thioureas" refer to a broad class of compounds with the general structure . Thioureas are related to thioamides, e.g. , where R is methyl, ethyl, etc. Structure and bonding Thiourea is a planar molecule. The C=S bond distance is 1.71 Å. The C-N distances average 1.33 Å. The weakening of the C-S bond by C-N pi-bonding is indicated by the short C=S bond in thiobenzophenone, which is 1.63 Å. Thiourea occurs in two tautomeric forms, of which the thione form predominates in aqueous solutions. The equilibrium constant has been calculated as ''K''eq is . The thiol form, which is also known as an isothiourea, can be encountered in substituted compounds such as i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isothiouronium
In organic chemistry, isothiouronium is a functional group with the formula SC(NH2)2sup>+ (R = alkyl, aryl) and is the acid salt of isothiourea. The H centres can also be replaced by alkyl and aryl. Structurally, these cations resemble guanidinium cations. The CN2S core is planar and the C–N bonds are short. Synthesis Salts comprising these cations are typically prepared by alkylation of thiourea: :SC(NH2)2 + RX → SC(NH2)2sup>+X− Reactions Hydrolysis of isothiouronium salts gives thiols. : SC(NH2)2sup>+X− + NaOH → RSH + OC(NH2)2 + NaX Isothiouronium salts in which the sulfur has been alkylated, such as ''S''-methylisothiourea hemisulfate (CAS number: 867-44-7), will convert amines into guanidinium Guanidine is the compound with the formula HNC(NH2)2. It is a colourless solid that dissolves in polar solvents. It is a strong base that is used in the production of plastics and explosives. It is found in urine predominantly in patients experie ... groups. This ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dithiol
In organic chemistry, a dithiol is a type of organosulfur compound with two thiol () functional groups. Their properties are generally similar to those of monothiols in terms of solubility, odor, and volatility. They can be classified according to the relative location of the two thiol groups on the organic backbone. File:C6H4(SH)2.svg, Benzene-1,2-dithiol, the parent aromatic dithiol File:1,3-Propandithiol Structural Formula V1.svg, Propane-1,3-dithiol File:Meso-2,3-dimercaptosuccinic-acid-2D-skeletal-A-configurations-labelled.png, The drug meso-2,3-dimercaptosuccinic acid File:Dimercaprol.svg, Dimercaprol ("British anti-Lewisite"), an early antidote for arsenic poisoning File:Dihydrolipoic-acid-2D-skeletal.png, Dihydrolipoic acid, a vitamin File:Dithiothreitol.png, Dithiothreitol, a reagent in protein biochemistry Geminal dithiols Geminal dithiols have the formula RR'C(SH)2. They are derived from aldehydes and ketones by the action of hydrogen sulfide. Their stability con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xylylene
In organic chemistry, a xylylene (sometimes quinone-dimethide) is any of the constitutional isomers having the formula C6H4(CH2)2. These compounds are related to the corresponding quinones and quinone methides by replacement of the oxygen atoms by CH2 groups. ''ortho''- and ''para''-xylylene are best known, although neither is stable in solid or liquid form. The ''meta'' form is a diradical. Certain substituted derivatives of xylylenes are however highly stable, such as tetracyanoquinodimethane and the xylylene dichlorides. p-Xylylene ''p''-Xylylene forms upon pyrolysis of ''p''-xylene or, more readily, the α-substituted derivatives. ''p''-Xylylene dimerizes with moderate efficiency to give ''p''-cyclophane: Further heating of the ''p''-cyclophane gives poly(''para''-xylylene). o-Xylylenes o-Xylylenes (''o''-quinodimethanes) are often generated in situ, e.g., by the pyrolysis of the corresponding sulfone. Another method involves 1,4-elimination of ortho benzylic silanes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Carbonyl
Iron pentacarbonyl, also known as iron carbonyl, is the compound with formula . Under standard conditions Fe( CO)5 is a free-flowing, straw-colored liquid with a pungent odour. Older samples appear darker. This compound is a common precursor to diverse iron compounds, including many that are useful in small scale organic synthesis. Properties Iron pentacarbonyl is a homoleptic metal carbonyl, where carbon monoxide is the only ligand complexed with a metal. Other examples include octahedral Cr(CO)6 and tetrahedral Ni(CO)4. Most metal carbonyls have 18 valence electrons, and Fe(CO)5 fits this pattern with 8 valence electrons on Fe and five pairs of electrons provided by the CO ligands. Reflecting its symmetrical structure and charge neutrality, Fe(CO)5 is volatile; it is one of the most frequently encountered liquid metal complexes. Fe(CO)5 adopts a trigonal bipyramidal structure with the Fe atom surrounded by five CO ligands: three in equatorial positions and two axially b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xylylene Dichloride
The chemical compound xylylene dichloride (C6H4(CH2Cl)2) is a white to light yellow sandlike solid. This compound can be classified as a benzyl halide. Xylylene dichloride is used as a vulcanizing agent to harden rubbers. It catalyzes the crosslinking of phenolic resins. Structure and reactivity The structure of xylylene dichloride is characterized by an benzene ring with two chloromethyl groups and four hydrogen atoms bound to it. The chloromethyl groups can be located on different sites on the ring, leading to a few different possible forms. These forms are: *''o''-xylylene dichloride: 1,2-bis(chloromethyl)benzene *''m''-xylylene dichloride: 1,3-bis(chloromethyl)benzene *''p''-xylylene dichloride: 1,4-bis(chloromethyl)benzene The reactive groups of xylylene dichloride are the two CH2Cl groups. Synthesis Xylylene dichloride can be synthesized from benzenedimethanol by reaction with hydrogen chloride. It has also been produced by photochemical chlorination of ortho-xylene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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