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Encyclopedia > Isoprene
Isoprene
Chemical name 2-Methyl-1,3-butadiene
Chemical formula C5H8
Molecular mass 68.11 g/mol
Density 0.681 g/ml
Melting point -145.95 °C
Boiling point 34.067 °C
CAS number 78-79-5
SMILES CC(=C)C=C
Image:Isoprene-Structure.png

Isoprene is a common synonym for the chemical compound 2-methyl-1,3-butadiene. It is commonly used in industry, is an important biological material, and can be a harmful environmental pollutant and toxicant when present in excess quantities. IUPAC nomenclature is a systematic way of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... See also Avogadros number Atomic mass unit Dalton (unit) External links Learning by Simulations Calculation of Molecular Formulas from Molecular Masses Categories: Chemistry stubs | Mass | Chemical properties ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... The melting point of a solid is the temperature at which it changes state from solid to liquid. ... Allah is who made all of this. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII alpha-numeric strings. ... Image File history File links Created on March 21, 2005 by User:Jag123 using ChemDraw Ultra 8. ... Image File history File links Created on March 21, 2005 by User:Jag123 using Chem3D Ultra 8. ...


At room temperature, isoprene is a colorless liquid which is highly flammable and easily ignited. It can form explosive mixtures in air and is highly reactive, capable of polymerizing explosively when heated. The United States Department of Transportation considers isoprene a hazardous material and requires special marking, labeling, and transportation for it. Established October 15, 1966 Activated April 1, 1967 Secretary Norman Mineta Deputy Secretary Maria Cino Budget $58 billion (2004 estimate) Employees 58,622 (2004 estimate) The United States Department of Transportation (DOT) is a Cabinet department of the United States government concerned with transport. ...


It is most readily available industrially as a by-product of the thermal cracking of naphtha or oil. About 95% of isoprene production is used to produce cis-1,4-polyisoprene - a synthetic version of natural rubber. In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ... Naphtha is a group of various volatile flammable liquid hydrocarbon mixtures used primarily as feedstocks in refineries for the reforming process and in the petrochemical industry for the production of olefins in steam crackers. ... Rubber is an elastic hydrocarbon polymer which occurs as a milky emulsion (known as latex) in the sap of a number of plants but can also be produced synthetically. ...


Natural rubber is a polymer of isoprene - most often cis-1,4-polyisoprene - with a molecular weight of 100,000 to 1,000,000. Typically, a few percent of other materials, such as proteins, fatty acids, resins and inorganic materials are found in high quality natural rubber. Rubber is an elastic hydrocarbon polymer which occurs as a milky emulsion (known as latex) in the sap of a number of plants but can also be produced synthetically. ... A polymer is a generic term used to describe a substantially long molecule. ...


Some natural rubber sources are composed of trans-1,4-polyisoprene, a structural isomer which has similar, but not identical properties. In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of bonds between atoms, but in which the atoms are arranged differently. ...

Contents


Biological roles and effects

Isoprene is formed naturally in plants and animals and is generally the most common hydrocarbon found in the human body. The estimated production rate of isoprene in the human body is 15 µmol/kg/h, equivalent to approximately 17 mg/day for a 70 kg person. Isoprene is also common in low concentrations in many foods. Isoprene is produced in the chloroplasts of leaves of certain tree species through the DMAPP pathway; the enzyme isoprene synthase is responsible for its biosynthesis. The amount of isoprene released from isoprene-emitting vegetation depends on leaf mass, leaf area, light (particularly photosynthetic photon flux density), and leaf temperature. Thus, during the night, little isoprene is emitted from tree leaves while daytime emissions are expected to be substantial (~5 ppbV) during hot and sunny days. In chemistry, a hydrocarbon is any chemical compound that consists only of the elements carbon (C) and hydrogen (H). ... The mole (symbol: mol) is the SI term identifying the number of particles in a given amount of matter. ...


With a global biogenic production in the range of 350–500 Tg of carbon/year, isoprene has a large impact on atmospheric processes and is thus an important compound in the field of Atmospheric Chemistry. Isoprene affects the oxidative state of large air masses, is an important precursor for ozone, a pollutant in the lower atmosphere. Furthermore, isoprene forms secondary organic aerosols through photooxidation with OH radicals which also have wide-ranging health effects, particularly for the respiratory tract, and reduce visibility due to light scattering effects. Because of its atmospheric importance, much work has been devoted to emission studies from isoprene-emitting vegetation, and, kinetic and mechanistic studies of isoprene oxidation via OH radicals, ozone, and NO3 radicals. Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earths atmosphere and that of other planets is studied. ... Ozone (O3) is an allotrope of oxygen, the molecule consisting of three oxygen atoms instead of the more stable diatomic O2. ... http://visibleearth. ... In physical chemistry, chemical kinetics or reaction kinetics study reaction rates in a chemical reaction. ... SN2 reaction scheme In chemistry, a reaction mechanism is the step by step sequence of reactions by which overall chemical change occurs. ...


It is a common structural motif in biological systems. The terpenes (for example, the carotenes are tetraterpenes) are derived from isoprene, as are the terpenoids and coenzyme Q. Also derived from isoprene are phytol, retinol (vitamin A), tocopherol (vitamin E), dolichols, and squalene. Heme A has an isoprenoid tail, and lanosterol, the sterol precursor in animals, is derived from squalene and hence from isoprene. The functional isoprene units in biological systems are dimethylallyl pyrophosphate (DMAPP) and its isomer isopentenyl pyrophosphate (IPP), which are used in the biosynthesis of terpenes and lanosterol derivatives. Terpenes are a class of hydrocarbons, produced by many plants, particularly conifers. ... Carotene is a terpene, an orange photosynthetic pigment, important for photosynthesis. ... The terpenoids, sometimes referred to as isoprenoids, are a class of naturally occurring chemicals similar to terpenes, derived from five-carbon isoprene units assembled and modified in thousands of ways. ... Coenzyme Q (CoQ), also known as ubiquinone or ubiquinol, is a biologically active quinone with an isoprenoid side chain, related in structure to vitamin K and vitamin E. // History Coenzyme Q was first discovered in 1957 by professor F. L. Crane and colleagues at the University of Wisconsin Enzyme Institute. ... Retinol, the dietary form of vitamin A, is a fat-soluble, antioxidant vitamin important in vision and bone growth. ... Retinol, the dietary form of vitamin A, is a fat-soluble, antioxidant vitamin important in vision and bone growth. ... Tocopherol, or Vitamin E, is a fat-soluble vitamin in eight forms that is an important antioxidant. ... Tocopherol, or Vitamin E, is a fat-soluble vitamin in eight forms that is an important antioxidant. ... Dolichol is an isoprenoid compound similar to cholesterol. ... Squalene is a natural organic compound obtained primarily from shark liver oil. ... A hæm or heme is a metal-containing cofactor that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin. ... Squalene is a natural organic compound obtained primarily from shark liver oil. ...


In virtually all organisms, isoprene derivatives are synthetised by the HMG-CoA reductase pathway. Addition of these chains to proteins is termed isoprenylation. The HMG-CoA reductase pathway, also known as MVA pathway or mevalonate-dependent (MAD) route, is an important cellular metabolic pathway present in virtually all organisms. ... Prenylation or isoprenylation is the addition of hydrophobic molecules to a protein to facilitate its attachment to the cell membrane. ...


According to the United States Department of Health and Human Services Eleventh Edition Report on Carcinogens, isoprene is reasonably expected to be a human carcinogen. Tumors have been observed in multiple locations in multiple test species exposed to isoprene vapor. No adequate human studies of the relationship between isoprene exposure and human cancer have been reported. The United States Department of Health and Human Services, often abbreviated HHS, is a Cabinet department of the United States government with the goal of protecting the health of all Americans and providing essential human services. ... In pathology, a carcinogen is any substance or agent that promotes cancer. ...


Biosynthesis and Its Inhibition by Statins

HMG-CoA reductase inhibitors, also known as the group of cholesterol-lowering drugs called statins, inhibit the synthesis of mevalonate. Mevalonate is a precursor to isopentenyl pyrophosphate, which combines with its isomer, dimethyl allyl pyrophosphate, in repeating alternations to form isoprene (or polyprenyl) chains. Lovastatin, the first statin to be marketed The statins form a class of hypolipidemic agents. ...


Statins are used to lower cholesterol, which is synthesized from the 15-carbon isoprenoid, farnesyl pyrophosphate, but also inhibit all other isoprenes, including coenzyme Q10. This flow chartshows the biosynthesis of isoprenes, and the point at which statins act to inhibit this process. Lovastatin, the first statin to be marketed The statins form a class of hypolipidemic agents. ... Cholesterol chemical structure Cholesterol is a steroid, a lipid, and an alcohol, found in the cell membranes of all body tissues, and transported in the blood plasma of all animals. ... Coenzyme Q (CoQ), also known as ubiquinone or ubiquinol, is a biologically active quinone with an isoprenoid side chain, related in structure to vitamin K and vitamin E. The oxidized structure of CoQ, or Q, is given here: The various kinds of Coenzyme Q can be distinguished by the number...


Reference

Merck Index, Eleventh Edition, ISBN 911910-28-X. The Merck Index is an encyclopedia of chemicals, drugs and biologicals with over 10,000 monographs on single substances or groups of related compounds. ...


Poisson, N., M. Kanakidou, and P. J. Crutzen, "Impact of nonmethanehydrocarbons on tropospheric chemistry and the oxidizing power of the global troposphere: 3-dimensional modelling results," Journal of Atmospheric Chemistry, vol. 36, pp. 157–230, 2000.


Monson, R. K., and E. A. Holland, "Biospheric trace gas fluxes and their control over tropospheric chemistry," Annual Review of Ecological Systems, vol. 32, pp. 547–+, 2001.


Claeys, M., B. Graham, G. Vas, W. Wang, R. Vermeylen, V. Pashynska, J. Cafmeyer, P. Guyon, M. O. Andreae, P. Artaxo, and W. Maenhaut, "Formation of secondary organic aerosols through photooxidation of isoprene," Science, vol. 303, pp. 1173–1176, 2004.


Pier, P. A., and C. McDuffie, "Seasonal isoprene emission rates and model comparisons using whole-tree emissions from white oak," Journal of Geophysical Research, vol. 102, pp. 23,963–23,971, 1997.


Poschl, U., R. von Kuhlmann, N. Poisson, and P. J. Crutzen, "Development and intercomparison of condensed isoprene oxidation mechanisms for global atmospheric modeling," Journal of Atmospheric Chemistry, vol. 37, pp. 29–52, 2000.


External link

Flow Chart Showing the Biosynthesis of Isoprenes


Report on Carcinogens, Eleventh Edition; U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program


  Results from FactBites:
 
Isoprene - Wikipedia, the free encyclopedia (858 words)
Isoprene is formed naturally in plants and animals and is generally the most common hydrocarbon found in the human body.
Isoprene is produced in the chloroplasts of leaves of certain tree species through the DMAPP pathway; the enzyme isoprene synthase is responsible for its biosynthesis.
Isoprene affects the oxidative state of large air masses, is an important precursor for ozone, a pollutant in the lower atmosphere.
Home page of Dr. Mark Potosnak, Assistant Research Professor, DEES/DRI (894 words)
Isoprene affects oxidation cycles in the atmosphere, and in turn the rate of emission depends on both the genetic potential of the plant and environmental factors.
Isoprene is produced enzymatically in the chloroplast of many plant species and may provide a protective benefit to the photosynthetic apparatus during transient episodes of heat stress.
Isoprene in the atmosphere is reduced by the hydroxyl radical (and by ozone to a lesser extent) on a timescale of 2 hours, which couples isoprene emissions and atmospheric chemistry.
  More results at FactBites »

 
 

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