Effects of mixed H2O-CH3CN solvents on the rate of hydrazinolysis of N-phenylphthalimide: Spectral and kinetic evidence for the occurrence of N-aminophthalimide on the reaction path

✍ Scribed by Azhar Ariffin; Sim Yoke Leng; Lai Chwee Lan; M. Niyaz Khan

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 207 KB
• Volume: 37
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.20057

✦ Synopsis

Abstract

Kinetic study on the cleavage of N‐phenylphthalimide (NPhPT) in the presence of 0.05 M NH~2~NH~2~ and mixed H~2~O‐CH~3~CN solvents reveals the occurrence of reaction scheme

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where A, B, C, C~1~, An, E, and F represent NPhPT, o‐CO^−^~2~C~6~H~4~CONHC~6~H~5~, o‐CONHNH~2~C~6~H~4~‐ CONHC~6~H~5~, N‐aminophthalimide, aniline, o‐CO^−^~2~C~6~H~4~CONHNH~2~, and o‐CONHNH~2~C~6~H~4~‐CONHNH~2~, respectively. But, in the presence of either nonbuffered ⩾0.20 M NH~2~NH~2~ hydrazine buffer of pH ∼7.30–8.26 with total buffer concentration ([Buf]~T~) of >0.02 M, further conversion of F to 2,3‐dihydrophthalazine‐1,4‐dione (DHPD) has been detected depending upon the length of the reaction time (t), the values of [Buf]~T~, and pH. It has been shown that the rate of conversion of C~1~ to F is much faster than that of C to C~1~ which is much faster than that of F to DHPD. The reaction step A → C involves general base (GB) catalysis, while step C → C~1~ seems to involve specific base–general acid (GA) and GB‐GB catalysis. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 147–161, 2005