594-60-5Relevant articles and documents
Mechanism of Hydration of Simple Olefins in Aqueous Solution. cis- and trans-Cyclooctene
Chiang, Y.,Kresge, A. J.
, p. 6363 - 6367 (1985)
Rates of hydration of cis- and trans-cyclooctene and 2,3-dimethyl-2-butene to the corresponding alcohols have been measured in concentrated and dilute aqueous perchloric acid, and those of the latter two olefins in bisulfate ion and phosphoric acid buffer solutions as well.The systems examined in buffers show general-acid catalysis.The reaction of trans-cyclooctene is not reversible, but those of cis-cyclooctene and 2,3-dimethyl-2-butene are; for cis-cycloctene, K=/=1.8 and for 2,3-dimethyl-2-butene, K ca. 4.For hydration of trans-cyclooctene, ΔH*= 22 kcal mol-1, ΔS*= 1 cal K-1 mol-1, and kH(1+)(25 deg C)= 5.2x10-4 M-1 s-1; for the hydration of cis-cyclooctene, ΔH*= 24 kcal mol-1, ΔS*= -10 cal K-1 mol-1, and kH(1+)( 25 deg C)= 2.1x10-7 M-1 s-1; and for the rate of approach to equilibrium in the 2,3-dimethyl-2-butene system, kH(1+)( 25 deg C)= 2.9x10-4 M-1 s-1.The lifetime of tertiary carbocations such as that formed by protonation of 2,3-dimethyl-2-butene is estimated to be τ ca. 10-10 s in dilute aqueous solution, which allows this ion to be a viable, solvationally equilibrated intermediate in the hydration reaction.The secondary cyclooctyl cation is likewise judged to be a solvationally equilibrated species in concentrated aqueous acids, with τ ca. 5x10-8 to 5x10-9 s in the 45-55 wt percent HClO4 solutions used for the hydration of cis-cyclooctene.In dilute aqueous solution, however, carbocation lifetimes are shorter, and τ ca. 5x10-12 s is estimated for the cyclooctyl cation in dilute acids such as those used for the hydration of trans-cyclooctene.Species as short-lived as this can probably still be reaction intermediates, but they are not solvationally equilibrated and may have to react by preassociation mechanisms; an argument is presented that shows that such a mechanism is likely not to be required in the hydration of trans-cyclooctene.
Application method of Grignard reaction
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Paragraph 0026-0039, (2021/03/31)
The invention discloses an application method of a Grignard reaction, belonging to the technical field of organic synthesis. According to the invention, a two-way dropwise adding mode is adopted, andpreparation of a Grignard reagent and a Grignard reaction are carried out at the same time; as the Grignard reaction is carried out while the Grignard reagent is prepared, the concentration of the Grignard reagent in a reaction system is reduced, and coupling side reactions are reduced; the use amount of a solvent in the reaction system is reduced, the accumulation rate of raw materials is increased, yield is increased and cost is reduced; and meanwhile, in the reaction system, the activity of the Grignard reagent in the system is reduced due to the reduction of the concentration of the Grignard reagent, so an explosion risk caused by over-high concentration of the Grignard reagent during storage and reaction of the Grignard reagent is avoided.
Palladium-catalyzed selective generation of CO from formic acid for carbonylation of alkenes
Sang, Rui,Kucmierczyk, Peter,Dong, Kaiwu,Franke, Robert,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
supporting information, p. 5217 - 5223 (2018/04/24)
A general and selective palladium-catalyzed alkoxycarbonylation of all kinds of alkenes with formic acid (HCOOH, FA) is described. Terminal, di-, tri-, and tetra-substituted including functionalized olefins are converted into linear esters with high yields and regioselectivity. Key-to-success is the use of specific palladium catalysts containing ligands with built-in base, e.g., L5. Comparison experiments demonstrate that the active catalyst system not only facilitates isomerization and carbonylation of alkenes but also promotes the selective decomposition of HCOOH to CO under mild conditions.
