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Stopped-flow spectrometry enables the solution-phase study of chemical kinetics for fast reactions, typically with half-lives in the millisecond range. Initially, it was primarily used for investigating enzyme-catalyzed reactions but quickly became a staple in biochemistry, biophysics, and chemistry laboratories for tracking rapid chemical ...
[1] [2] [3] In the case of temperature jump, the perturbation involves rapid heating which changes the value of the equilibrium constant, followed by relaxation to equilibrium at the new temperature. The heating usually involves discharging of a capacitor (in the kV range) through a small volume (< 1 mL) of a conducting solution containing the ...
There are two reactions occurring simultaneously in the solution. In the first, slow reaction, iodine is produced: H 2 O 2 + 2 I − + 2 H + → I 2 + 2 H 2 O. In the second, fast reaction, iodine is reconverted to two iodide ions by the thiosulfate: 2 S 2 O 2− 3 + I 2 → S 4 O 2− 6 + 2 I −. After some time the solution changes color to ...
A classic example of NGP is the reaction of a sulfur or nitrogen mustard with a nucleophile, the rate of reaction is much higher for the sulfur mustard and a nucleophile than it would be for a primary or secondary alkyl chloride without a heteroatom. [5] Ph−S−CH 2 −CH 2 −Cl reacts with water 600 times faster than CH 3 −CH 2 −CH 2 ...
In general terms, the free energy change (ΔG) of a reaction determines whether a chemical change will take place, but kinetics describes how fast the reaction is. A reaction can be very exothermic and have a very positive entropy change but will not happen in practice if the reaction is too slow.
Cu 2 O in water at room temperature was found also to catalyze the same reaction in 15 minutes with 91% yield. [18] The first reaction mechanism proposed included one catalytic copper atom; but isotope, kinetic, and other studies have suggested a dicopper mechanism may be more relevant.
Solution polymerization is a method of industrial polymerization. In this procedure, a monomer is dissolved in a non-reactive solvent that contains a catalyst or initiator. The reaction results in a polymer which is also soluble in the chosen solvent. Heat released by the reaction is absorbed by the solvent, reducing the reaction rate.
A fluorous technology was described by Curran [16] The fluorous synthesis employs functionalized perfluoroalkyl (Rf) groups like 4,4,5,5,6,6,7,7,8,8,9,9,9-Tridecafluorononyl {CF 3 (CF 2) 4 CF 2 CH 2 CH 2-} group attached to substrates or reagents. The Rf groups make it possible to remove either the product or the reagents from the reaction mixture.