International Journal of Chemical Kinetics p. 746 - 758 (2006)
Update date:2022-08-16
Topics:
Sim, Yoke-Leng
Ariffin, Azhar
Khan, M. Niyaz
The values of pseudo first-order rate constants (kobs) for the cleavage of AM 2-hydroxyphenyl)phthalamic acid (7), obtained at 4.9 × 10-2 M HCl, 35°C, and within CH3CN content range 2-80% (v/v) in mixed aqueous solvent are smaller than kobs for the cleavage of N-(2-methoxyphenyllphthalamic acid (8), obtained under almost similar experimental conditions, by nearly 1.5- to 2-fold. These observations show the absence of expected intramolecular general acid catalysis due to 2-OH group in 7. The values of kobs for the cleavage of 7 and 8 decrease by more than 20-fold with the increase in the content of CH3CN from 2 to 80-82% (v/v) in mixed aqueous solvent. The kinetic data reveal that in acidic aqueous cleavage of 7, N-cyclization (leading to the formation of imide) and O-cyclization (leading to the formation of phthalic anhydride) vary from ~10 to 15% and ~90 to 85%, respectively, with the increase in CH 3CN content from 2 to 80% (v/v). Similar increase in CH3CN content causes increase in N-cyclization from ~0 to 5% and decrease in O-cyclization from ~100 to 95% in the acidic aqueous cleavage of 8. Some speculative, yet conceivable, reasons for nearly 10 and 0% N-cyclization in the cleavage of respective 7 and 8 at low content of CH3CN have been described.
View MoreJining Shengrun Chemical Industry Co., Ltd.
Contact:+86-537-7121666 ,
Address:West Ring Road,Wenshang County Shandong Province
Shanghai Pengkai Chemical Co.,Ltd
Contact:+86-21-60526671
Address:No.4226 Duzhuang Rd Minhang District Shanghai China
Contact:0792-8228321
Address:10TH Floor No.121 binjiang Road Xunyang District
Hangzhou Dingyan Chem Co., Ltd
website:http://www.dingyanchem.com
Contact:86-571-87157530-8001
Address:RM.1118,NO.1 Building, Baiyun Tower,Jianggan Area, Hangzhou city, China,310004
Shenzhen ZheYi Chemicals Co.,LTD(Shanghai Branch)
Contact:+86-21-54159691
Address:Room1002,Building No.2, Lane 98 Bixiu Road,Minhang District, Shanghai,China 201100
Doi:10.1021/jm00001a025
(1995)Doi:10.1016/j.ica.2015.05.024
(2015)Doi:10.1007/s11164-016-2743-0
(2017)Doi:10.1039/c4sm00941j
(2014)Doi:10.1039/c39870000683
(1987)Doi:10.1021/acs.macromol.9b02571
(2020)