Journal of the American Chemical Society p. 4710 - 4715 (1985)
Update date:2022-08-30
Topics:
Grunwald, Ernest
There is a long-standing evidence that in the general base catalyzed addition of alcohols to formaldehyde, C...O bond formation and proton transfer occur simultaneously.Structure-energy relations for this reaction are complicated.The slopes of Bronsted plots vary greatly, even for structurally similar alcohols, and plots of log k vs. pKa of the alcohols go through minima.The data thus provide good material for testing the author's recent theory of structure-energy relations for concerted reactions.The theoretical equations are nonlinear and depend specifically on the reaction mechanism.Of four mechanisms, only that favored by previous independent work fits the data well, even onto reproducing the rate-constant minima.The rate-determining step of this mechanism is R'CH2COO(-) + RCH2OH + H2C=O -> R'CH2COOH + RCH2OCH2O(-).R ranges in electronegativity from CH3 to CF3, R' from H to CN.Assuming this mechanism to be correct, progress of C...O bond formation (u<*>) and proton transfer (v<*>) were deduced from the theoretical equations.The results show that mean progress at the transition state, (u<*> + v<*>)/2, varies only sightly with substitution, but that disparity of progress of the two reaction events, (v<*>-u<*>)/2, varies markedly both with R and R' and changes sign within the series.Rate-constant minima occur near points where u<*> = v<*>, thus proving the effectiveness of disparity at lowering the free energy of activation.
View MoreShenZhen InnoSyn Biotech Co.,Ltd
website:http://www.innosyns.com
Contact:+86-755-28351685
Address:Floor 5 & 6, Building A1, HAIKEXING Strategic Innovative Industrial Park, 16 BaoShan Road, PingShan District
Shanghai Bosman Industrial Co., Ltd
Contact:86-21-63065878-8006
Address:Rm907, No.1611, North Sichuan Road, Hongkou District, Shanghai, 200080 China
Zhuzhou Farshine Chemical Industry Co., Ltd
Contact:0086-731-28482786
Address:No. 1,Shui Xian Road, He Tang Dictrict,Hunan-412000,China
Hengshui Bangsheng Environmental Protection and Technology Co., Ltd
Contact:+86-318-2275966
Address:1956 Renmin Road, Hengshui city, Hebei, China
JIAXING SUNS INTERNATIONAL TRADE CO LTD
Contact:18367306858
Address:No.123,Huixin Avenue,Huimin Dist
Doi:10.1016/j.dyepig.2018.03.058
(2018)Doi:10.1248/cpb.38.1438
(1990)Doi:10.1002/jhet.3799
(2020)Doi:10.1021/ja990885i
(2000)Doi:10.1016/j.tetlet.2005.05.132
(2005)Doi:10.1002/ardp.201700076
(2017)