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Diethylbenzenes
Diethylbenzene (DEB) refers to any of three isomers with the formula C6H4(C2H5)2. Each consists of a benzene ring and two ethyl Ethyl may refer to: Arts and entertainment * Cold Ethyl, a Swedish rock band *Ethyl Sinclair, a character in the ''Dinosaurs'' television show Science and technology * Ethyl group, an organic chemistry moiety * Ethyl alcohol (or ethanol) * E ... substituents. The meta and para have the greater commercial significance. All are colorless liquids. Nomenclature * ''Ortho'': known as 1,2-diethylbenzene and ''o''-diethylbenzene. * ''Meta'': known as 1,3-diethylbenzene and ''m''-diethylbenzene. * ''Para'': known as 1,4-diethylbenzene and ''p''-diethylbenzene. Production and applications Diethylbenzenes arise as side-products of the alkylation of benzene with ethylene, which can described as two steps. The first step is the industrial route to ethylbenzene, which is produced on a large scale as a precursor to styrene. :C6H6 + C2H4 → C6H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transalkylation
In organic chemistry, transalkylation is a chemical reaction involving the transfer of an alkyl group from one organic compound to another. The reaction is used for the transfer of methyl and ethyl groups between benzene rings. This is of particular value in the petrochemical industry to manufacture p-xylene, styrene, and other aromatic compounds. Motivation for using transalkylation reactions is based on a difference in production and demand for benzene, toluene, and xylenes. Transalkylation can convert toluene, which is overproduced, into benzene and xylene, which are under-produced. Zeolites are often used as catalysts in transalkylation reactions. Disproportionation Transalkylation, as used by the petrochemical industry, is often used to convert toluene into benzene and xylenes. This is achieved through a disproportionation reaction of toluene in which one toluene molecule transfers its methyl group to another one. The reaction is not selective, and the xylene produced can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomer
In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – 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] |
Benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline. It is used primarily as a precursor to the manufacture of chemicals with more complex structure, such as ethylbenzene and cumene, of which billions of kilograms are produced annually. Although benzene is a major industrial chemical, it finds limited use in consumer items because of its toxicity. History Discovery The word "''benzene''" derives from "''gum benzoin''" (benzoin res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethyl Group
In organic chemistry, an ethyl group (abbr. Et) is an alkyl substituent with the formula , derived from ethane (). ''Ethyl'' is used in the International Union of Pure and Applied Chemistry's nomenclature of organic chemistry for a saturated two-carbon moiety in a molecule, while the prefix "''eth-''" is used to indicate the presence of two carbon atoms in the molecule. Ethylation Ethylation is the formation of a compound by introduction of the ethyl group. The most widely practiced example of this reaction is the ethylation of benzene with ethylene to yield ethylbenzene, a precursor to styrene, which is a precursor to polystyrene. Approximately 24.7 million tons of ethylbenzene were produced in 1999. :: Many ethyl-containing compounds are generated by electrophilic ethylation, i.e. treatment of nucleophiles with sources of Et+. Triethyloxonium tetrafluoroborate t3OF4 is such a reagent. For good nucleophiles, less electrophilic reagents are employed, such as ethyl h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arene Substitution Pattern
Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon. ''Ortho'', ''meta'', and ''para'' substitution * In ''ortho''-substitution, two substituents occupy positions next to each other, which may be numbered 1 and 2. In the diagram, these positions are marked R and ''ortho''. * In ''meta''-substitution the substituents occupy positions 1 and 3 (corresponding to R and ''meta'' in the diagram). * In ''para''-substitution, the substituents occupy the opposite ends (positions 1 and 4, corresponding to R and ''para'' in the diagram). The toluidines serve as an example for these three types of substitution. Synthesis Electron donating groups, for example amino, hydroxyl, alkyl, and phenyl groups tend to be ''ortho''/''para''-directors, and electron withdrawing groups such as nitro, nitrile, and ketone groups, tend to be ''meta''-directors. Propert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethylbenzene
Ethylbenzene is an organic compound with the formula . It is a highly flammable, colorless liquid with an odor similar to that of gasoline. This monocyclic aromatic hydrocarbon is important in the petrochemical industry as an reaction intermediate in the production of styrene, the precursor to polystyrene, a common plastic material. In 2012, more than 99% of ethylbenzene produced was consumed in the production of styrene. Occurrence and applications Ethylbenzene occurs naturally in coal tar and petroleum. The dominant application of ethylbenzene is its role as an intermediate in the production of polystyrene. Catalytic dehydrogenation of ethylbenzene gives hydrogen and styrene: : → C6H5CH=CH2 + As of May 2012, more than 99% of all the ethylbenzene produced is used for this purpose. Ethylbenzene hydroperoxide, a reagent and radical initiator, is produced by autoxidation of ethylbenzene: :C6H5CH2CH3 + O2 → C6H5CH(O2H)CH3 Niche uses Ethylbenzene is added to gasoline as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Styrene
Styrene () is an organic compound with the chemical formula C6H5CH=CH2. This derivative of benzene is a colorless oily liquid, although aged samples can appear yellowish. The compound evaporates easily and has a sweet smell, although high concentrations have a less pleasant odor. Styrene is the precursor to polystyrene and several copolymers. Approximately 25 million tonnes of styrene were produced in 2010, increasing to around 35 million tonnes by 2018. Natural occurrence Styrene is named after storax balsam (often commercially sold as ''styrax''), the resin of Liquidambar trees of the Altingiaceae plant family. Styrene occurs naturally in small quantities in some plants and foods (cinnamon, coffee beans, balsam tree (other), balsam trees and peanuts) and is also found in coal tar. History In 1839, the German apothecary Eduard Simon isolated a volatile liquid from the resin (called ''storax'' or ''styrax'' (Latin)) of the Liquidambar styraciflua, American sweetgu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeolite
Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These positive ions can be exchanged for others in a contacting electrolyte solution. exchanged zeolites are particularly useful as solid acid catalysts. The term ''zeolite'' was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have been stilbite, produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material ''zeolite'', from the Greek , meaning "to boil" and , meaning "stone". Zeolites occur naturally but are also produced industrially on a large scale. , 253 unique zeolite frameworks have been identified, and over 40 naturally occurring zeolite frameworks are known. Every new zeolite structure that is ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Divinylbenzene
Divinylbenzene (DVB) consists of a benzene ring bonded to two vinyl groups. It is related to styrene (vinylbenzene) by the addition of a second vinyl group.CRC Handbook of Chemistry and Physics 65Th Ed. It is a colorless liquid manufactured by the thermal dehydrogenation of isomeric diethylbenzenes. Under synthesis conditions, ''o''-divinylbenzene converts to naphthalene and thus is not a component of the usual mixtures of DVB. Production and use It is produced by dehydrogenation of diethylbenzene: : C6H4(C2H5)2 → C6H4(C2H3)2 + 2 H2 Divinylbenzene is usually encountered as a 2:1 mixture of ''m''- and ''p''-divinylbenzene, containing also the corresponding isomers of ethylvinylbenzene. Styrene and divinylbenzene react to form the copolymer styrene-divinylbenzene, S-DVB or Sty-DVB. The resulting cross-linked polymer is mainly used for the production of ion exchange resin and Merrifield resin Merrifield Resin is a cross-linked polystyrene resin that carries a chloromet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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