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Thioacetone
Thioacetone is an organosulfur compound belonging to the -thione group called thioketones, with a chemical formula (CH3)2CS. It is an unstable orange or brown substance that can be isolated only at low temperatures. Above , thioacetone readily converts to a polymer and a trimer, trithioacetone. It has an extremely potent, unpleasant odor, and is considered one of the worst-smelling chemicals known. Thioacetone was first obtained in 1889 by Baumann and Fromm, as a minor impurity in their synthesis of trithioacetone.William H. Sharkey (1979): "Polymerization through the carbon-sulfur double bond". ''Polymerization'', series ''Advances in Polymer Science'', volume 17, pages 73-103. Preparation Thioacetone is usually obtained by cracking the cyclic trimer trithioacetone, CH3)2CSsub>3. The trimer is prepared by pyrolysis of allyl isopropyl sulfide or by treating acetone with hydrogen sulfide in the presence of a Lewis acid. The trimer cracks at to give the thione. : Polymeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thioketones
In organic chemistry, thioketones (; also known as thiones or thiocarbonyls) are organosulfur compounds related to conventional ketones in which the oxygen has been replaced by a sulfur. Instead of a structure of , thioketones have the structure , which is reflected by the prefix "thio-" in the name of the functional group. Unhindered alkylthioketones typically tend to form polymers or rings. Structure and bonding The C=S bond length of thiobenzophenone is 1.63 Å, which is comparable to 1.64 Å, the C=S bond length of thioformaldehyde, measured in the gas phase. Due to steric interactions, the phenyl groups are not coplanar and the dihedral angle SC-CC is 36°. Unhindered dialkylthiones polymerize or oligomerize but thiocamphor is well characterized red solid. Consistent with the double bond rule, most alkyl thioketones are unstable with respect to dimerization.Organosulfur Chemistry I: Topics in Current Chemistry, 1999, Volume 204/1999, 127-181, The energy difference between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodoacetone
Iodoacetone is an organoiodine compound with the chemical formula The substance is a colorless liquid under normal conditions, soluble in ethanol. Synthesis The reaction of acetone and iodine produces iodoacetone. The reaction is typically acid catalysed and first order with respect to acetone and the acid catalyst: : + --> + : See also *Bromoacetone *Chloroacetone *Fluoroacetone *Thioacetone Thioacetone is an organosulfur compound belonging to the -thione group called thioketones, with a chemical formula (CH3)2CS. It is an unstable orange or brown substance that can be isolated only at low temperatures. Above , thioacetone readily co ... References {{Chemical agents Organoiodides Lachrymatory agents Ketones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thioketone
In organic chemistry, thioketones (; also known as thiones or thiocarbonyls) are organosulfur compounds related to conventional ketones in which the oxygen has been replaced by a sulfur. Instead of a structure of , thioketones have the structure , which is reflected by the prefix "thio-" in the name of the functional group. Unhindered alkylthioketones typically tend to form polymers or rings. Structure and bonding The C=S bond length of thiobenzophenone is 1.63 Å, which is comparable to 1.64 Å, the C=S bond length of thioformaldehyde, measured in the gas phase. Due to steric interactions, the phenyl groups are not coplanar and the dihedral angle SC-CC is 36°. Unhindered dialkylthiones polymerize or oligomerize but thiocamphor is well characterized red solid. Consistent with the double bond rule, most alkyl thioketones are unstable with respect to dimerization.Organosulfur Chemistry I: Topics in Current Chemistry, 1999, Volume 204/1999, 127-181, The energy difference between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluoroacetone
Fluoroacetone is an organofluorine compound with the chemical formula . In contrast to trifluoroacetone, the compound has one fluorine atom. Under normal conditions, the substance is a colorless liquid. Fluoroacetone is also a highly toxic and flammable compound. Fumes of fluoroacetone can form an explosive mixture with air. Synthesis Fluoroacetone can be obtained by a reaction of triethylamine trihydrofluoride with bromoacetone. Applications Fluoroacetone is used as a catalyst to study the kinetics of the ketone-catalysed decomposition of peroxymonosulfuric acid (Caro's acid). It is also a precursor material for the production of higher fluoroketones. Fluoroacetone has not been used as a lachrymatory substance in contrast to other halogenated acetone derivatives, such as bromoacetone or chloroacetone. See also *Bromoacetone *Chloroacetone *Iodoacetone *Thioacetone Thioacetone is an organosulfur compound belonging to the -thione group called thioketones, with a chemical fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2,2,4,4,6,6-Hexamethyl-1,3,5-trithiane
Trithioacetone (2,2,4,4,6,6-hexamethyl-1,3,5-trithiane) is an organic chemical with formula . Its covalent structure is , that is, a six-membered ring of alternating carbon and sulfur atoms, with two methyl groups attached to each carbon. It can be viewed as a derivative of 1,3,5-trithiane, with methyl-group substituents for all of the hydrogen atoms in that parent structure. The compound Trithioacetone is a stable cyclic trimer of thioacetone (propane-2-thione), which by itself is an unstable compound. In contrast, the analogous trioxane compound, 2,2,4,4,6,6-hexamethyl-1,3,5-trioxane ( Triacetone), with oxygen atoms in place of the sulfur atoms, seems to be unstable, while its corresponding monomer acetone (2-propanone) is stable. Synthesis Trithioacetone was first made in 1889 by Baumann and Fromm, by reaction of hydrogen sulfide with acetone. In the presence of an acidified catalyst at 25 °C, one obtains a product that is 60–70% trithioacetone, 30–40% of 2,2-prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromoacetone
Bromoacetone is an organic compound with the formula . It is a colorless liquid although impure samples appear yellow or even brown. It is a lachrymatory agent and a precursor to other organic compounds. Occurrence in nature Bromoacetone is present (less than 1%) in the essential oil of a seaweed (''Asparagopsis taxiformis'') from the vicinity of the Hawaiian Islands. Synthesis Bromoacetone is available commercially, sometimes stabilized with magnesium oxide. It was first described in the 19th century, attributed to N. Sokolowsky. Bromoacetone is prepared by combining bromine and acetone, with catalytic acid. As with all ketones, acetone enolizes in the presence of acids or bases. The alpha carbon then undergoes electrophilic substitution with bromine. The main difficulty with this method is over-bromination, resulting in di- and tribrominated products. If a base is present, bromoform is obtained instead, by the haloform reaction. Applications It was used in World War I as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trithioacetone
Trithioacetone (2,2,4,4,6,6-hexamethyl-1,3,5-trithiane) is an organic chemical with chemical formula, formula . Its Covalent bond, covalent structure is , that is, a six-membered ring of alternating carbon and sulfur atoms, with two methyl groups attached to each carbon. It can be viewed as a derivative of 1,3,5-trithiane, with methyl-group substituents for all of the hydrogen atoms in that parent structure. The compound Trithioacetone is a stable cyclic compound, cyclic trimer of thioacetone (propane-2-thione), which by itself is an unstable compound. In contrast, the analogous 1,3,5-trioxane, trioxane compound, 2,2,4,4,6,6-hexamethyl-1,3,5-trioxane (Triacetone), with oxygen atoms in place of the sulfur atoms, seems to be unstable, while its corresponding monomer acetone (2-propanone) is stable. Synthesis Trithioacetone was first made in 1889 by Baumann and Fromm, by reaction of hydrogen sulfide with acetone. In the presence of an acidified catalyst at 25 °C, one obtains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethylene Oxide
Ethylene oxide is an organic compound with the chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered Ring (chemistry), 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 silver catalyst. The reactivity that is responsible for many of ethylene oxide's hazards also makes it useful. Although too dangerous for direct household use and generally unfamiliar to consumers, ethylene oxide is used for making many consumer products as well as non-consumer chemicals and intermediates. These products include detergents, thickeners, solvents, plastics, and various organic chemicals such as ethylene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroacetone
Chloroacetone is a chemical compound with the formula . At STP it is a colourless liquid with a pungent odour. On exposure to light, it turns to a dark yellow-amber colour. It was used as a tear gas in World War I. Synthesis Chloroacetone may be synthesized from the reaction between chlorine and diketene, or by the chlorination of acetone. Applications Chloroacetone is used to make dye couplers for colour photography, and is an intermediate in chemical manufacturing. It is also used in the Feist-Benary synthesis of furans. *Reaction of phenoxide with chloroacetone gives phenoxyacetone, which is used to make a wide variety of different pharmaceuticals. A catalytic amount of potassium iodide is also necessary to facilitate a Finkelstein reaction. Purification Chloroacetone purchased from commercial suppliers contains 5% impurities including mesityl oxide, which is not removed by distillation. Mesityl oxide can be oxidized using acidified KMnO4 to form a diol (followed by s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiobenzophenone
Thiobenzophenone is an organosulfur compound with the formula (C6H5)2CS. It is the prototypical thioketone. Unlike other thioketones that tend to dimerize to form rings and polymers, thiobenzophenone is quite stable, although it photoxidizes in air to form benzophenone and sulfur. Thiobenzophenone is deep blue and dissolves readily in many organic solvents. Structure The C=S bond length of thiobenzophenone is 1.63 Å, which is comparable to 1.64 Å, the C=S bond length of thioformaldehyde, measured in the gas phase. Due to steric interactions, the phenyl groups are not coplanar and the dihedral angle SC-CC is 36°.Sustmann, R.; Sicking, W.; Huisgen, R. "A Computational Study of the Cycloaddition of Thiobenzophenone S-Methylide to Thiobenzophenone". J. Am. Chem. Soc. 2003, 125, 14425-14434. A variety of thiones with structures and stability related to thiobenzophenone have also been prepared. Synthesis One of the first reported syntheses of thiobenzophenone involves the reaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leeds
Leeds () is a city and the administrative centre of the City of Leeds district in West Yorkshire, England. It is built around the River Aire and is in the eastern foothills of the Pennines. It is also the third-largest settlement (by population) in England, after London and Birmingham. The city was a small manorial borough in the 13th century and a market town in the 16th century. It expanded by becoming a major production centre, including of carbonated water where it was invented in the 1760s, and trading centre (mainly with wool) for the 17th and 18th centuries. It was a major mill town during the Industrial Revolution. It was also known for its flax industry, iron foundries, engineering and printing, as well as shopping, with several surviving Victorian era arcades, such as Kirkgate Market. City status was awarded in 1893, a populous urban centre formed in the following century which absorbed surrounding villages and overtook the nearby York population. It is locate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freiburg Im Breisgau
Freiburg im Breisgau (; abbreviated as Freiburg i. Br. or Freiburg i. B.; Low Alemannic German, Low Alemannic: ''Friburg im Brisgau''), commonly referred to as Freiburg, is an independent city in Baden-Württemberg, Germany. With a population of about 230,000 (as of 31 December 2018), Freiburg is the List of cities in Baden-Württemberg by population, fourth-largest city in Baden-Württemberg after Stuttgart, Mannheim, and Karlsruhe. The population of the Freiburg metropolitan area was 656,753 in 2018. In the Southern Germany, south-west of the country, it straddles the Dreisam river, at the foot of the Schlossberg (Freiburg), Schlossberg. Historically, the city has acted as the hub of the Breisgau region on the western edge of the Black Forest in the Upper Rhine Plain. A famous old German university town, and Roman Catholic Archdiocese of Freiburg, archiepiscopal seat, Freiburg was incorporated in the early twelfth century and developed into a major commercial, intellectual, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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