|
Isobutene
Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula . It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value. Production Polymer and chemical grade isobutylene is typically obtained by dehydrating tertiary butyl alcohol (TBA) or catalytic dehydrogenation of isobutane (Catofin or similar processes).. Gasoline additives methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), respectively, are produced by reacting methanol or ethanol with isobutylene contained in butene streams from olefin steam crackers or refineries, or with isobutylene from dehydrated TBA. Isobutylene is not isolated from the olefin or refinery butene stream before the reaction, as separating the ethers from the remaining butenes is simpler. Isobutylene can also be produced in high purities by "back-cracking" MTBE or ETBE at high temperatures and then separating the isobutylene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethyl Tert-butyl Ether
Ethyl ''tertiary''-butyl ether (ETBE), also known as ethyl ''tert''-butyl ether, is commonly used as an oxygenate gasoline additive in the production of gasoline from crude oil. ETBE offers equal or greater air quality benefits than ethanol, while being technically and logistically less challenging. Unlike ethanol, ETBE does not induce evaporation of gasoline, which is one of the causes of smog, and does not absorb moisture from the atmosphere. Production Ethyl tert-butyl ether is manufactured industrially by the acidic etherification of isobutylene with ethanol at a temperature of 30–110 °C and a pressure of 0,8–1,3 MPa. The reaction is carried out with an acidic ion-exchange resin as a catalyst. Suitable reactors are fixed-bed reactors such as tube bundle or circulation reactors in which the reflux can be cooled optionally. Ethanol, produced by fermentation and distillation, is more expensive than methanol, which is derived from natural gas. Therefore, MTBE, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethenolysis
In organic chemistry, ethenolysis is a chemical process in which internal olefins are degraded using ethylene () as the reagent. The reaction is an example of cross metathesis. The utility of the reaction is driven by the low cost of ethylene as a reagent and its selectivity. It produces compounds with terminal alkene functional groups (α-olefins), which are more amenable to other reactions such as polymerization and hydroformylation. The general reaction equation is: :\ce + \longrightarrow \ce + \ce Ethenolysis is a form of methylenation, i.e., the installation of methylene () groups. Applications Using ethenolysis, higher molecular weight internal alkenes can be converted to more valuable terminal alkenes. The Shell higher olefin process (SHOP process) uses ethenolysis on an industrial scale. The SHOP α-olefin mixtures are separated by distillation, the higher molecular weight fractions are isomerized by alkaline alumina catalysts in the liquid phase. The resulting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isooctane
2,2,4-Trimethylpentane, also known as isooctane or iso-octane, is an organic compound with the formula (CH3)3CCH2CH(CH3)2. It is one of several isomers of octane (C8H18). This particular isomer is the standard 100 point on the octane rating scale (the zero point is ''n''-heptane). It is an important component of gasoline, frequently used in relatively large proportions (around 10%) to increase the knock resistance of fuel. Strictly speaking, if the standard meaning of ‘iso’ is followed, the name ''isooctane'' should be reserved for the isomer 2-methylheptane. However, 2,2,4-trimethylpentane is by far the most important isomer of octane and historically it has been assigned this name. Production Isooctane is produced on a massive scale in the petroleum industry by alkylation of isobutene with isobutane. This process is conducted in alkylation units in the presence of acid catalysts. It can also be produced from isobutylene by dimerization using an Amberlyst catalyst to pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a light, volatile, colourless, flammable liquid with a distinctive alcoholic odour similar to that of ethanol (potable alcohol). A polar solvent, methanol acquired the name wood alcohol because it was once produced chiefly by the destructive distillation of wood. Today, methanol is mainly produced industrially by hydrogenation of carbon monoxide. Methanol consists of a methyl group linked to a polar hydroxyl group. With more than 20 million tons produced annually, it is used as a precursor to other commodity chemicals, including formaldehyde, acetic acid, methyl tert-butyl ether, methyl benzoate, anisole, peroxyacids, as well as a host of more specialised chemicals. Occurrence Small amounts of methanol are present in normal, healthy hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Tert-butyl Ether
Methyl ''tertiary''-butyl ether (MTBE), also known as methyl tert-butyl ether and ''tert''-butyl methyl ether, is an organic compound with a structural formula (CH3)3COCH3. MTBE is a volatile, flammable, and colorless liquid that is sparingly soluble in water. Primarily used as a fuel additive, MTBE is blended into gasoline to increase its octane rating and knock resistance, and reduce unwanted emissions. Production and properties MTBE is manufactured via the chemical reaction of methanol and isobutylene. Methanol is primarily derived from natural gas, where steam reforming converts the various light hydrocarbons in natural gas (primarily methane) into carbon monoxide and hydrogen. The resulting gases then further react in the presence of a catalyst to form methanol. Isobutylene can be produced through a variety of methods. One process the isomerization of ''n''-butane into isobutane, which then undergoes dehydrogenation to form the isobutylene. In the Halcon process, t-Butyl hyd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dehydrogenation
In chemistry, dehydrogenation is a chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. At its simplest, it is useful way of converting alkanes, which are relatively inert and thus low-valued, to olefins, which are reactive and thus more valuable. Alkenes are precursors to aldehydes (), alcohols (), polymers, and aromatics. As a problematic reaction, the fouling and inactivation of many catalysts arises via coking, which is the dehydrogenative polymerization of organic substrates. Enzymes that catalyze dehydrogenation are called dehydrogenases. Heterogeneous catalytic routes Styrene Dehydrogenation processes are used extensively to produce aromatics in the petrochemical industry. Such processes are highly endothermic and require temperatures of 500 °C and above. Dehydrogenation also converts saturated fats to unsatura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butyl Rubber
Butyl rubber, sometimes just called "butyl", is a synthetic rubber, a copolymer of isobutylene with isoprene. The abbreviation IIR stands for isobutylene isoprene rubber. Polyisobutylene, also known as "PIB" or polyisobutene, (C4H8)n, is the homopolymer of isobutylene, or 2-methyl-1-propene, on which butyl rubber is based. Butyl rubber is produced by polymerization of about 98% of isobutylene with about 2% of isoprene. Structurally, polyisobutylene resembles polypropylene, but has two methyl groups substituted on every other carbon atom, rather than one. Polyisobutylene is a colorless to light yellow viscoelastic material. It is generally odorless and tasteless, though it may exhibit a slight characteristic odor. Properties Butyl rubber has excellent impermeability to gas diffusion, and the long polyisobutylene segments of its polymer chains give it good flex properties. The formula for PIB is: –(–CH2–C(CH3)2–)n– The formula for IIR is: It can be made from the mono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomers Of Butylene
Butene, also known as butylene, is an alkene with the formula . The word ''butene'' may refer to any of the individual compounds. They are colourless gases that are present in crude oil as a minor constituent in quantities that are too small for viable extraction. Butene is therefore obtained by catalytic cracking of long-chain hydrocarbons left during refining of crude oil. Cracking produces a mixture of products, and the butene is extracted from this by fractional distillation. Butene can be used as the monomer for polybutene, but this polymer is more expensive than alternatives with shorter carbon chains such as polypropylene. Polybutene is therefore used in more specialized applications. Butenes are more commonly used to make copolymer (mixed with another monomer such as ethylene). Isomers Among the molecules which have the chemical formula four isomers are alkenes. All four of these hydrocarbons have four carbon atoms and one double bond in their molecules, but have diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neohexene
Neohexene is the hydrocarbon compound with the chemical formula . It is a colorless liquid, with properties similar to other hexenes. It is a precursor to commercial synthetic musk perfumes. Preparation and reactions Neohexene is prepared by ethenolysis of diisobutene, an example of a metathesis reaction: :\ce + \longrightarrow \ce + \ce It is a building block to synthetic musks by its reaction with ''p''-cymene. It is also used in the industrial preparation of terbinafine. In the study of C-H activation, neohexene is often used as a hydrogen acceptor.{{cite journal, last1 = Liu, first1 = Fuchen, last2 = Pak, first2 = Esther B., last3 = Singh, first3 = Bharat, last4 = Jensen, first4 = Craig M., last5 = Goldman, first5 = Alan S., title = Dehydrogenation of ''n''-Alkanes Catalyzed by Iridium "Pincer" Complexes: Regioselective Formation of α-Olefins, journal = J. Am. Chem. Soc. The ''Journal of the American Chemical Society'' is a weekly peer-reviewed scientific journal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trans-2-Butene
But-2-ene is an acyclic alkene with four carbon atoms. It is the simplest alkene exhibiting ''cis''/''trans''-isomerism (also known as (''E''/''Z'')-isomerism); that is, it exists as two geometric isomers ''cis''-but-2-ene ((''Z'')-but-2-ene) and ''trans-''but-2-ene ((''E'')-but-2-ene). It is a petrochemical, produced by the catalytic cracking of crude oil or the dimerization of ethylene. Its main uses are in the production of gasoline (petrol) and butadiene,. although some but-2-ene is also used to produce the solvent butanone via hydration to 2-butanol followed by oxidation. The two isomers are extremely difficult to separate by distillation because of the proximity of their boiling points (~4 °C for ''cis'' and ~1 °C for ''trans'' ). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butene
Butene, also known as butylene, is an alkene with the formula . The word ''butene'' may refer to any of the individual compounds. They are colourless gases that are present in crude oil as a minor constituent in quantities that are too small for viable extraction. Butene is therefore obtained by catalytic cracking of long-chain hydrocarbons left during refining of crude oil. Cracking produces a mixture of products, and the butene is extracted from this by fractional distillation. Butene can be used as the monomer for polybutene, but this polymer is more expensive than alternatives with shorter carbon chains such as polypropylene. Polybutene is therefore used in more specialized applications. Butenes are more commonly used to make copolymer (mixed with another monomer such as ethylene). Isomers Among the molecules which have the chemical formula four isomers are alkenes. All four of these hydrocarbons have four carbon atoms and one double bond in their molecules, but have diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cis-2-Butene
But-2-ene is an acyclic alkene with four carbon atoms. It is the simplest alkene exhibiting cis-trans isomerism, ''cis''/''trans''-isomerism (also known as (''E''/''Z'')-isomerism); that is, it exists as two geometric isomers ''cis''-but-2-ene ((''Z'')-but-2-ene) and ''trans-''but-2-ene ((''E'')-but-2-ene). It is a petrochemical, produced by the catalytic cracking of crude oil or the dimerization of ethylene. Its main uses are in the production of gasoline (petrol) and butadiene,. although some but-2-ene is also used to produce the solvent butanone via Hydration reaction, hydration to 2-Butanol, 2-butanol followed by oxidation. The two isomers are extremely difficult to separate by distillation because of the proximity of their boiling points (~4 °C for ''cis'' and ~1 °C for ''trans'' [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
