Trapp mixture: Difference between revisions
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The '''Trapp mixture''' is a specific [[mixture]] of organic [[solvent]]s that allows [[chemical reaction]]s to take place at very low temperatures.<ref>{{cite journal |author1=Köbrich, G. |author2=Trapp, H. | journal = [[Chem. Ber.]] | year = 1966 | volume = 99 | issue = 2 | pages = 680 | doi = 10.1002/cber.19660990243 | title = Darstellung und thermische Stabilität von 1-Chlor-2.2-diaryl-vinyllithium-Verbindungen ('The formation and thermal stability of 1-chloro-2,2-diaryl-vinyl lithium compounds')}}</ref> It is made up of [[THF]]:[[diethyl ether]]:[[pentane]] in a 4:4:1 ratio which remains liquid down to −110 °C and the same solvents in a 4:1:1 ratio remain a liquid down to −120 °C. This solvent system retains a low viscosity until just before freezing and it allows a lower temperature reaction than pure THF, which melts at −108.4 °C. An illustrative application of Trapp solvent is the preparation of vinyllithium by [[Organolithium reagent#lithium halogen exchange|lithium halogen exchange]] from [[vinyl bromide]] and [[tert-Butyllithium|''tert''-butyllithium]].<ref>Eric K. Eisenhart, Bernard Bessieres "Vinyllithium" e-EROS Encyclopedia of Reagents for Organic Synthesis, 2001. {{DOI|10.1002/047084289X.rv015.pub2}}.</ref> The low temperatures suppress the reaction of the strongly basic organolithium reagent with the THF. |
The '''Trapp mixture''' is a specific [[mixture]] of organic [[solvent]]s that allows [[chemical reaction]]s to take place at very low temperatures.<ref>{{cite journal |author1=Köbrich, G. |author2=Trapp, H. | journal = [[Chem. Ber.]] | year = 1966 | volume = 99 | issue = 2 | pages = 680 | doi = 10.1002/cber.19660990243 | title = Darstellung und thermische Stabilität von 1-Chlor-2.2-diaryl-vinyllithium-Verbindungen ('The formation and thermal stability of 1-chloro-2,2-diaryl-vinyl lithium compounds')}}</ref> It is made up of [[THF]]:[[diethyl ether]]:[[pentane]] in a 4:4:1 ratio which remains liquid down to −110 °C and the same solvents in a 4:1:1 ratio remain a liquid down to −120 °C. This solvent system retains a low viscosity until just before freezing and it allows a lower temperature reaction than pure THF, which melts at −108.4 °C. An illustrative application of Trapp solvent is the preparation of [[vinyllithium]] by [[Organolithium reagent#lithium halogen exchange|lithium halogen exchange]] from [[vinyl bromide]] and [[tert-Butyllithium|''tert''-butyllithium]].<ref>Eric K. Eisenhart, Bernard Bessieres "Vinyllithium" e-EROS Encyclopedia of Reagents for Organic Synthesis, 2001. {{DOI|10.1002/047084289X.rv015.pub2}}.</ref> The low temperatures suppress the reaction of the strongly basic organolithium reagent with the THF. |
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== References == |
== References == |
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Revision as of 19:48, 29 April 2017
The Trapp mixture is a specific mixture of organic solvents that allows chemical reactions to take place at very low temperatures.[1] It is made up of THF:diethyl ether:pentane in a 4:4:1 ratio which remains liquid down to −110 °C and the same solvents in a 4:1:1 ratio remain a liquid down to −120 °C. This solvent system retains a low viscosity until just before freezing and it allows a lower temperature reaction than pure THF, which melts at −108.4 °C. An illustrative application of Trapp solvent is the preparation of vinyllithium by lithium halogen exchange from vinyl bromide and tert-butyllithium.[2] The low temperatures suppress the reaction of the strongly basic organolithium reagent with the THF.
References
- ^ Köbrich, G.; Trapp, H. (1966). "Darstellung und thermische Stabilität von 1-Chlor-2.2-diaryl-vinyllithium-Verbindungen ('The formation and thermal stability of 1-chloro-2,2-diaryl-vinyl lithium compounds')". Chem. Ber. 99 (2): 680. doi:10.1002/cber.19660990243.
- ^ Eric K. Eisenhart, Bernard Bessieres "Vinyllithium" e-EROS Encyclopedia of Reagents for Organic Synthesis, 2001. doi:10.1002/047084289X.rv015.pub2.
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