of p-nitrophenol in the reaction of nine substituted phenolates with p-nitrophenylacetate has been determined by spectrophotometric measurements in absolute ethanol at 22°. The phenolate anion is the reactive species and competes with ethoxide anion, arising from solvolysis of the phenolate, for nucleophilic attack on the ester carbonyl carbon atoms. From the observed reaction rates the solvolysis constants
在22°C的无水乙醇中通过分光光度法测定了九种取代酚盐与对硝基苯乙酸酯反应中对硝基苯酚的释放速率。酚盐阴离子是反应性物质,并且与酚盐的溶剂分解产生的乙氧化物阴离子竞争,对酯羰基碳原子进行亲核攻击。从观察到的反应速率获得酚的溶剂分解常数和p K a值。酚盐阴离子的二阶速率常数与p K a相关相应的苯酚的Bronstedβ值为0.57。进行了与芳基硫醚对乙醇中相同底物的亲核反应性的比较。决定速率的步骤可能是芳基硫醚化物反应中离去基团的排出,而苯酚盐反应中亲核试剂的进攻。
Kinetics of the reaction of phenyl picrates with phenoxide ions in water. Concerted or stepwise?
作者:Michael R. Crampton、Ian A. Robotham
DOI:10.1002/poc.3172
日期:2013.12
A kinetic study is reported of the exchange reactions of substituted phenoxide ions with some ring‐substituted 2,4,6‐trinitrophenyl ethers in water. The βrønsted diagrams formed by plotting log k, where k is the second‐order rate constant for reaction, versus pKa show a distinct change in slope when ΔpKa = 0 (ΔpKa being the difference in pKa values of the leaving group and nucleophile). This is consistent
Acid dissociation constants of phenols and reaction mechanism for the reactions of substituted phenyl benzoates with phenoxide anions in absolute ethanol
作者:Ik-Hwan Um、Yeon-Ju Hong、Dong-Sook Kwon
DOI:10.1016/s0040-4020(97)00227-5
日期:1997.4
Aciddissociationconstants of 10 substituted phenols have been measured by a kinetic method together with second-order rate constants for the reactions of aryl benzoates (X-C6H4CO-OC6H4-Y) with Z-substituted phenoxide (Z-C6H4O−) and EtO in absolute ethanol at 25.0±0.1°C. The kinetic results support a stepwise mechanism for the present acyl-transfer reaction.
已通过动力学方法测量了10种取代苯酚的酸解离常数以及苯甲酸芳基酯(XC 6 H 4 CO-OC 6 H 4 -Y)与Z-取代酚盐(ZC 6 H 4 ø - )和环氧乙烷的无水乙醇在25.0±0.1℃。动力学结果支持本酰基转移反应的逐步机理。
The influence of the structure of tetracoordinate phosphorus acid esters on the catalytic effect of the sodium dodecyl sulfate-hexanol-water ternary reverse micellar system
作者:L. Ya. Zakharova、F. G. Valeeva、R. A. Shagidullina、L. A. Kudryavtseva
DOI:10.1007/bf02495077
日期:2000.8
The catalytic effect of the sodium dodecyl sulfate-hexanol-water ternary reverse micellarsystem in the alkaline hydrolysis ofO-alkylO′-aryl chloromethylphosphonates as a function of the substrate structure was studied. The micellareffect is mainly determined by a change in the electronic properties of the substituents, while the hydrophobicity plays a secondary role. The kinetic data were examined
The phenomenology of differently constructed Brønsted-type plots
作者:E. Buncel、R. Tarkka、S. Hoz
DOI:10.1039/c39930000109
日期:——
Two different methodologies for the construction of Brønsted-type plots are compared; curved plots using the traditional approach and linear plots by a novel approach are obtained for the reaction of phenoxides with p-nitrophenyl diphenylphosphinate in dimethyl sulfoxide–water media at 25 °C.
比较了构建 Brønsted 型图的两种不同方法;对于酚盐与对硝基苯基二苯基次膦酸酯在二甲基亚砜-水介质中于 25 °C 的反应,获得了使用传统方法的曲线图和使用新方法的线性图。