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1,3-cyclohexadiene
Cyclohexa-1,3-diene is an organic compound with the formula (C2H4)(CH)4. It is a colorless, flammable liquid. Its refractive index is 1.475 (20 Ā°C, D). A naturally occurring derivative of 1,3-cyclohexadiene is terpinene, a component of pine oil. Synthesis Cyclohexadiene is prepared by the dehydrobromination of 1,2-dibromocyclohexane: :(CH2)4(CHBr)2 + 2 NaH ā (CH2)2(CH)4 + 2 NaBr + 2 H2 Reactions Useful reactions of this diene are cycloadditions, such as the Diels-Alder reaction. Conversion of cyclohexa-1,3-diene to benzene + hydrogen is exothermic by about 25 kJ/mol in the gas phase. :cyclohexane ā cyclohexa-1,3-diene + 2 H2 (Ī''H'' = +231.5 kJ/mol; endothermic) :cyclohexane ā benzene + 3 H2 (Ī''H'' = +205 kJ/mol; endothermic) :cyclohexa-1,3-diene ā benzene + H2 (Ī''H'' = -26.5 kJ/mol; exothermic) Compared with its isomer cyclohexa-1,4-diene, cyclohexa-1,3-diene is about 1.6 kJ/mol more stable. Cyclohexadiene and its derivatives form metal-alkene complexes. Ill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terpinene
The terpinenes are a group of isomeric hydrocarbons that are classified as monoterpenes. They each have the same molecular formula and carbon framework, but they differ in the position of carbon-carbon double bonds. Ī±-Terpinene has been isolated from cardamom and marjoram oils, and from other natural sources. Ī²-Terpinene has no known natural source but has been prepared from sabinene. Ī³-Terpinene and Ī“-terpinene (also known as terpinolene) have been isolated from a variety of plant sources. They are all colorless liquids with a turpentine-like odor. Production and uses Ī±-Terpinene is produced industrially by acid-catalyzed rearrangement of Ī±-pinene. It has perfume and flavoring properties but is mainly used to confer pleasant odor to industrial fluids. Hydrogenation gives the saturated derivative ''p''-menthane. Biosynthesis of Ī±-terpinene The biosynthesis of Ī±-terpinene and other terpenoids starts with the isomerization of geranyl pyrophosphate to linalyl pyroph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,4-cyclohexadiene
1,4-Cyclohexadiene is an organic compound with the formula C6H8. It is a colourless, flammable liquid that is of academic interest as a prototype of a large class of related compounds called terpenoids, an example being Ī³-terpinene. An isomer of this compound is 1,3-cyclohexadiene. Synthesis and reactions In the laboratory, substituted 1,4-cyclohexadienes are synthesized by Birch reduction of related aromatic compounds using an alkali metal dissolved in liquid ammonia and a proton donor such as an alcohol. In this way, over reduction to the fully saturated ring is avoided. 1,4-Cyclohexadiene and its derivatives are easily aromatized, the driving force being the formation of an aromatic ring. The conversion to an aromatic system may be used to trigger other reactions, such as the Bergman cyclization The Masamune-Bergman cyclization or Masamune-Bergman reaction or Masamune-Bergman cycloaromatization is an organic reaction and more specifically a rearrangement reaction taking p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruthenium Trichloride
Ruthenium(III) chloride is the chemical compound with the formula RuCl3. "Ruthenium(III) chloride" more commonly refers to the hydrate RuCl3Ā·''x''H2O. Both the anhydrous and hydrated species are dark brown or black solids. The hydrate, with a varying proportion of water of crystallization, often approximating to a trihydrate, is a commonly used starting material in ruthenium chemistry. Preparation and properties Anhydrous ruthenium(III) chloride is usually prepared by heating powdered ruthenium metal with chlorine. In the original synthesis, the chlorination was conducted in the presence of carbon monoxide, the product being carried by the gas stream and crystallising upon cooling. Two allotropes of RuCl3 are known. The black Ī±-form adopts the CrCl3-type structure with long Ru-Ru contacts of 346 pm. This allotrope has honeycomb layers of Ru3+ which are surrounded with an octahedral cage of Clā anions. The ruthenium cations are magnetic residing in a low-spin J~1/2 ground st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,4-Cyclohexadiene
1,4-Cyclohexadiene is an organic compound with the formula C6H8. It is a colourless, flammable liquid that is of academic interest as a prototype of a large class of related compounds called terpenoids, an example being Ī³-terpinene. An isomer of this compound is 1,3-cyclohexadiene. Synthesis and reactions In the laboratory, substituted 1,4-cyclohexadienes are synthesized by Birch reduction of related aromatic compounds using an alkali metal dissolved in liquid ammonia and a proton donor such as an alcohol. In this way, over reduction to the fully saturated ring is avoided. 1,4-Cyclohexadiene and its derivatives are easily aromatized, the driving force being the formation of an aromatic ring. The conversion to an aromatic system may be used to trigger other reactions, such as the Bergman cyclization The Masamune-Bergman cyclization or Masamune-Bergman reaction or Masamune-Bergman cycloaromatization is an organic reaction and more specifically a rearrangement reaction taking p ... [...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] |
Pine Oil
Pine oil is an essential oil obtained from a variety of species of pine, particularly ''Pinus sylvestris''. Typically, parts of the trees that are not used for lumber - stumps, etc. - are ground and subjected to steam distillation. As of 1995, synthetic pine oil was the "biggest single turpentine derivative." Synthetic pine oils accounted for 90% of sales as of 2000. Composition Pine oil is a higher boiling fraction from turpentine. Both synthetic and natural pine oil consists mainly of alpha-Terpineol, Ī±-terpineol, a C10 alcohol (b.p. 214ā217 Ā°C).''Merck Index'', 11th Edition, 7416. p. 1182 The detailed composition of natural pine oil depends on many factors, such as the species of the host plant. Synthetic pine oil is obtained by treating pinene with water in the presence of a catalytic amount of sulfuric acid. This treatment results in hydration reaction, hydration of the alkene and rearrangement of the pinene skeleton, yielding terpineols. Uses Industrially, pine oil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dehydrobromination
In chemistry, dehydrohalogenation is an elimination reaction which removes a hydrogen halide from a substrate. The reaction is usually associated with the synthesis of alkenes, but it has wider applications. Dehydrohalogenation from alkyl halides Traditionally, alkyl halides are substrates for dehydrohalogenations. The alkyl halide must be able to form an alkene, thus halides having no CāH bond on an adjacent carbon are not suitable substrates. Aryl halides are also unsuitable. Upon treatment with strong base, chlorobenzene dehydrohalogenates to give phenol via a benzyne intermediate. Base-promoted reactions to alkenes When treated with a strong base many alkyl chlorides convert to corresponding alkene. It is also called a Ī²-elimination reaction and is a type of elimination reaction. Some prototypes are shown below: :\begin \ce\ &\ce \\ \ce\ &\ce \\ \ce\ &\ce \end Here ethyl chloride reacts with potassium hydroxide, typically in a solvent such as ethanol, giving ethylene. Li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycloaddition
In organic chemistry, a cycloaddition is a chemical reaction in which "two or more Unsaturated hydrocarbon, unsaturated molecules (or parts of the same molecule) combine with the formation of a cyclic adduct in which there is a net reduction of the Multiplicity (chemistry)#Molecules, bond multiplicity". The resulting reaction is a cyclization reaction. Many but not all cycloadditions are Concerted reaction, concerted and thus pericyclic. Nonconcerted cycloadditions are not pericyclic. As a class of addition reaction, cycloadditions permit carbonācarbon bond formation without the use of a nucleophile or electrophile. Cycloadditions can be described using two systems of notation. An older but still common notation is based on the size of linear arrangements of atoms in the reactants. It uses parentheses: where the variables are the numbers of linear atoms in each reactant. The product is a cycle of size . In this system, the standard Diels-Alder reaction is a (4 + 2)-cyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomer
In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae ā that is, same number of atoms of each element ā but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Isomers do not necessarily share similar chemical or physical properties. Two main forms of isomerism are structural or constitutional isomerism, in which ''bonds'' between the atoms differ; and stereoisomerism or spatial isomerism, in which the bonds are the same but the ''relative positions'' of the atoms differ. Isomeric relationships form a hierarchy. Two chemicals might be the same constitutional isomer, but upon deeper analysis be stereoisomers of each other. Two molecules that are the same stereoisomer as each other might be in different conformational forms or be different isotopologues. The depth of analysis depends on the field of study or the chemical and physical properties of interest. The English word "isomer" () is a back-for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal-alkene Complex
In organometallic chemistry, a transition metal alkene complex is a coordination compound containing one or more alkene ligands. Such compounds are intermediates in many catalytic reactions that convert alkenes to other organic products.Elschenbroich, C. āOrganometallicsā (2006) Wiley-VCH: Weinheim. Mono- and dialkenes are often used as ligands in stable complexes. Monoalkenes The simplest monoalkene is ethene. Many complexes of ethene are known, including Zeise's salt (see figure), Rh2Cl2(C2H4)4, Cp*2Ti(C2H4), and the homoleptic Ni(C2H4)3. Substituted monoalkene include the cyclic cyclooctene, as found in chlorobis(cyclooctene)rhodium dimer. Alkenes with electron-withdrawing groups commonly bind strongly to low-valent metals. Examples of such ligands are TCNE, tetrafluoroethylene, maleic anhydride, and esters of fumaric acid. These acceptors form adducts with many zero-valent metals. Dienes, trienes, polyenes, keto-alkenes, and other complicated alkene ligands Butadiene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
(Benzene)ruthenium Dichloride Dimer
(Benzene)ruthenium dichloride dimer is the organoruthenium compound with the formula CH)RuCl This red-coloured, diamagnetic solid is a reagent in organometallic chemistry and homogeneous catalysis. Preparation, structure, and reactions The dimer is prepared by the reaction of cyclohexadienes with hydrated ruthenium trichloride. As verified by X-ray crystallography, each Ru center is coordinated to three chloride ligands and a Ī·-benzene. The complex can be viewed as an edge-shared bioctahedral structure. (Benzene)ruthenium dichloride dimer reacts with Lewis bases to give monometallic adducts: : CH)RuCl+ 2 PPh ā 2 (CH)RuCl(PPh) Related compounds * (cymene)ruthenium dichloride dimer, a more soluble analogue of (benzene)ruthenium dichloride dimer. * (mesitylene Mesitylene or 1,3,5-trimethylbenzene is a derivative of benzene with three methyl substituents positioned symmetrically around the ring. The other two isomeric trimethylbenzenes are 1,2,4-trimethylbenzene (pseudoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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