The oligomer concept is contrasted to that of a polymer, which is usually understood to have a large number of units, possibly thousands or millions. However, there is no sharp distinction between these two concepts. One proposed criterion is whether the molecule's properties vary significantly with the removal of one or a few of the units.[3]
An oligomer with a specific number of units is referred to by the Greek prefix denoting that number, with the ending -mer: thus dimer, trimer, tetramer, pentamer, and hexamer refer to molecules with two, three, four, five, and six units, respectively. The units of an oligomer may be arranged in a linear chain (as in melam, a dimer of melamine); a closed ring (as in trioxane, a cyclic trimer of formaldehyde); or a more complex structure (as in tellurium tetrabromide, a tetramer of TeBr4 with a cube-like core). If the units are identical, one has a homo-oligomer; otherwise one may use hetero-oligomer. An example of a homo-oligomeric protein is collagen, which is composed of three identical protein chains.
A pentamer unit of the major capsid protein VP1. Each monomer is in a different color.
The units of an oligomer may be connected by covalent bonds, which may result from bond rearrangement or condensation reactions, or by weaker forces such as hydrogen bonds. The term multimer (/ˈmʌltɪmər/) is used in biochemistry for oligomers of proteins that are not covalently bound. The major capsid protein VP1 that comprises the shell of the polio virus is a self-assembling multimer of 72 pentamers held together by local electric charges.
Oligomerization is a chemical process that converts monomers to macromolecular complexes through a finite degree of polymerization.[3]Telomerization is an oligomerization carried out under conditions that result in chain transfer, limiting the size of the oligomers.[4][3] (This concept is not to be confused with the formation of a telomere, a region of highly repetitive DNA at the end of a chromosome.)
Green oiledit
In the oil and gas industry, green oil refers to oligomers formed in all C2, C3, and C4 hydrogenation reactors of ethylene plants and other petrochemical production facilities; it is a mixture of C4 to C20 unsaturated and reactive components with about 90% aliphaticdienes and 10% of alkanes plus alkenes.[5] Different heterogeneous and homogeneous catalysts are operative in producing green oils via the oligomerization of alkenes.[6]
^ abcdeJenkins, A. D.; Kratochvíl, P.; Stepto, R. F. T.; Suter, U. W. (1996). "Glossary of basic terms in polymer science (IUPAC Recommendations 1996)". Pure and Applied Chemistry. 68 (12): 2287–2311. doi:10.1351/pac199668122287.Quote: Oligomer molecule: A molecule of intermediate relative molecular mass, the structure of which essentially comprises a small plurality of units derived, actually or conceptually, from molecules of lower relative molecular mass.
^Ghashghaee, Mohammad (2018). "Heterogeneous catalysts for gas-phase conversion of ethylene to higher olefins". Rev. Chem. Eng. 34 (5): 595–655. doi:10.1515/revce-2017-0003. S2CID 103664623.
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December 07, 2023
oligomer, hexamer, redirects, here, other, uses, hexamer, disambiguation, contents, green, also, references, external, links, chemistry, biochemistry, oligomer, molecule, that, consists, repeating, units, which, could, derived, actually, conceptually, from, sm. Hexamer redirects here For other uses see Hexamer disambiguation Contents 1 Green oil 2 See also 3 References 4 External links In chemistry and biochemistry an oligomer e ˈ l ɪ ɡ e m er is a molecule that consists of a few repeating units which could be derived actually or conceptually from smaller molecules monomers 1 2 3 The name is composed of Greek elements oligo a few and mer parts An adjective form is oligomeric 3 The 15 crown 5 crown ether a cyclic oligomer and its monomer ethylene oxide The oligomer concept is contrasted to that of a polymer which is usually understood to have a large number of units possibly thousands or millions However there is no sharp distinction between these two concepts One proposed criterion is whether the molecule s properties vary significantly with the removal of one or a few of the units 3 An oligomer with a specific number of units is referred to by the Greek prefix denoting that number with the ending mer thus dimer trimer tetramer pentamer and hexamer refer to molecules with two three four five and six units respectively The units of an oligomer may be arranged in a linear chain as in melam a dimer of melamine a closed ring as in trioxane a cyclic trimer of formaldehyde or a more complex structure as in tellurium tetrabromide a tetramer of TeBr4 with a cube like core If the units are identical one has a homo oligomer otherwise one may use hetero oligomer An example of a homo oligomeric protein is collagen which is composed of three identical protein chains A tetrapeptide a hetero oligomer of the amino acids valine green glycine black serine black and alanine blue The units were joined by condensation of the carboxylic acid group C O OH of one monomer with the amine group H2N of the next one Some biologically important oligomers are macromolecules like proteins or nucleic acids for instance hemoglobin is a protein tetramer An oligomer of amino acids is called an oligopeptide or just a peptide An oligosaccharide is an oligomer of monosaccharides simple sugars An oligonucleotide is a short single stranded fragment of nucleic acid such as DNA or RNA or similar fragments of analogs of nucleic acids such as peptide nucleic acid or Morpholinos A pentamer unit of the major capsid protein VP1 Each monomer is in a different color The units of an oligomer may be connected by covalent bonds which may result from bond rearrangement or condensation reactions or by weaker forces such as hydrogen bonds The term multimer ˈ m ʌ l t ɪ m er is used in biochemistry for oligomers of proteins that are not covalently bound The major capsid protein VP1 that comprises the shell of the polio virus is a self assembling multimer of 72 pentamers held together by local electric charges Many oils are oligomeric such as liquid paraffin Plasticizers are oligomeric esters widely used to soften thermoplastics such as PVC They may be made from monomers by linking them together or by separation from the higher fractions of crude oil Polybutene is an oligomeric oil used to make putty Oligomerization is a chemical process that converts monomers to macromolecular complexes through a finite degree of polymerization 3 Telomerization is an oligomerization carried out under conditions that result in chain transfer limiting the size of the oligomers 4 3 This concept is not to be confused with the formation of a telomere a region of highly repetitive DNA at the end of a chromosome Green oil editIn the oil and gas industry green oil refers to oligomers formed in all C2 C3 and C4 hydrogenation reactors of ethylene plants and other petrochemical production facilities it is a mixture of C4 to C20 unsaturated and reactive components with about 90 aliphatic dienes and 10 of alkanes plus alkenes 5 Different heterogeneous and homogeneous catalysts are operative in producing green oils via the oligomerization of alkenes 6 See also editGPCR oligomer Oligomery botany Protein oligomerReferences edit Oligomer Merriam Webster Retrieved 25 October 2014 IUPAC Compendium of Chemical Terminology 2nd ed the Gold Book 1997 Online corrected version 2006 oligomer molecule doi 10 1351 goldbook O04286 a b c d e Jenkins A D Kratochvil P Stepto R F T Suter U W 1996 Glossary of basic terms in polymer science IUPAC Recommendations 1996 Pure and Applied Chemistry 68 12 2287 2311 doi 10 1351 pac199668122287 Quote Oligomer molecule A molecule of intermediate relative molecular mass the structure of which essentially comprises a small plurality of units derived actually or conceptually from molecules of lower relative molecular mass IUPAC Compendium of Chemical Terminology 2nd ed the Gold Book 1997 Online corrected version 2006 telomerization doi 10 1351 goldbook T06260 Chemicals amp Polymers www pall com Ghashghaee Mohammad 2018 Heterogeneous catalysts for gas phase conversion of ethylene to higher olefins Rev Chem Eng 34 5 595 655 doi 10 1515 revce 2017 0003 S2CID 103664623 External links edit nbsp Media related to Oligomers at Wikimedia 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