Journal of the American Chemical Society p. 567 - 571 (1988)
Update date:2022-07-29
Topics:
Schade, Christian
Mayr, Herbert
Arnett, Edward M.
Scales of carbenium ion stabilities have been obtained from 1H NMR equilibrium studies of mixtures of partly ionized para-substituted diarylmethyl chlorides in CD2Cl2/BCl3 at -70 deg C and via calorimetric determination of the heats of ionization (ΔHi) of the alkyl chlorides (Ar2CHCl + BCl3 -> Ar2CH+BCl4-) in CH2Cl2/BCl3 at -70 deg C.The heats of the reactions of diarylmethyl tetrachloroborates with 2-methyl-1-pentene (Ar2CH+BCl4- + CH2=C(CH3)C3H7 -> Ar2CHCH2C(CH3)ClC3H7 + BCl3), which were determined by low-temperature calorimetry, increase from -53.1 kJ/mol for (H3CC6H4)2CH+BCl4- to -33.0 kJ/mol for the better stabilized (H3COC6H4)(H3CC6H4)CH+BCl4-.In contrast, the heats (ΔHa) of the Lewis acid catalyzed additions of the corresponding para-substituted diarylmethyl chlorides to 2-methyl-1-pentene are independent of the para substituents (ΔHa=-86.5 +/-2.7 kJ/mol).Similar values of ΔHa were obtained for the addition of p-anisylphenylmethyl chloride to trimethylethylene, styrene, β-methylstyrene, and isoprene. ΔHa is predominantly determined by the conversion of a ?(C=C) into a ?(C-C) bond, and the heats of addition of diarylmethyl tetrachloroborates to alkenes in CH2Cl2 are given by the equation ΔHb=(9.5 +/- 6.3 pKR+) kJ/mol.
View MoreSuzhou Jingye Medicine & Chemical Co., Ltd
website:http://www.jingyechem.cn
Contact:+86-512-66658588
Address:No. 88, Sanlian Street, Jinfeng Road, Suzhou New District, Jiangsu Province, P. R. China
Compro Shijiazhuang Fine Chemical Co., Ltd
Contact:0086-311-89689838
Address:Economic and Technological Development Zone of Shijiazhuang,Hebei
Yixing Bluwat Chemicals Co., Ltd.
Contact:+86 510 87821568
Address:Yongan Road, Yixing Chemical Industrial Park, Yixing, Jiangsu, China
Shandong Jincheng Zhonghua Bio-pharmaceutical Co.,Ltd
Contact:+86-533-5415882
Address:Zichuan Economic Development Zone,Zibo City,Shandong Province,China
Yantai Derun Liquid Crystal Materials Co. Ltd.
website:http://www.ytderun.com
Contact:86-535-6300169
Address:ROOM 90, XIANGFU STREET, FUSHAN NEW-HIGH-TECH IDUSTRY ZONE, YANTAI
Doi:10.1039/b901277j
(2009)Doi:10.1021/op010068e
(2002)Doi:10.1080/00397919908086466
(1999)Doi:10.1039/b616705e
(2007)Doi:10.1007/s11743-012-1332-5
(2012)Doi:10.1002/ejoc.201901825
(2020)