13160-79-7Relevant academic research and scientific papers
Formation of fibril structures in polymerizable, rod-coil-oligomer-modified epoxy networks
Yu, Yingfeng,Gao, Zongyong,Zhan, Guozhu,Li, Ang,Li, Shanjun,Gan, Wenjun,Crivello, James V.
, p. 2920 - 2928 (2007)
This paper describes the in situ preparation of fibrils in epoxy networks in which the fibril-like structures are cured polymerizable rod-coil oligomers. The epoxy-terminated α,ω-modified PEO oligomers, which are ABA rod-coil-rod oligomers with a poly(eth
Effect of partially aqueous solutions of different pH's on the hydrolysis rate of some Schiff bases
El-Taher,El-Haty,Hussien
, p. 79 - 91 (2007/10/03)
The mechanism of the hydrolysis of a series of Schiff bases derived from p-phenylenediamine and various aromatic aldehydes has been examined in aqueous media containing 40 wt% methanol, in the presence of NaOH. The base hydrolysis reaction of these compounds is strictly second-order kinetics, first-order with respect to the Schiff base and also to hydroxide ion, and the hydroxide ion attack on the free base becomes the rate-determining step under these basic conditions. The work is extended to include a systematic kinetic study on the hydrolysis reaction of the Schiff bases under investigation, in partially aqueous solutions of different pH's, in media containing 40 wt% methanol. A rate profile diagram of pH versus hydrolysis rate constant for all of the Schiff bases shows that the rate is minimal at alkaline region (pH > 8.96), and too rapid at strongly acidic media (pH 3.53).
Kinetics and Mechanism of Acid Hydrolysis of Some Mono-, Bi-Functional and Double Schiff Bases
El-Taher, M. A.,El-Haty, M. T.,Hussien, T. M.
, p. 203 - 215 (2007/10/03)
Kinetics of acid hydrolysis of dome mono, bi-functional or double Schiff bases derived from p-phenylenediamine and certain aromatic aldehydes have been investigated in aqueous media containing 40 wt percent methanol, in the presence of acetic acid. The acid hydrolysis reaction of these imines was found to follow second-order kinetics, strictly first-order with respect to each of the Schiff base and the acetic acid. Thus, the attack of water molecules on the protonated substrate is considered as the rate-determining step under these acidic conditions. The mono-functional imines showed relatively fast acid hydrolysis compared to that observed for bi-functional or double Schiff bases. This was discussed on the basis of the geometric flexibility of the molecular structure of such compounds. The effect of nature of the organic co-solvent on the hydrolysis rate was investigated and related to the polarizability of the hydrolysis medium. Furthermore, the various thermodynamic parameters have been calculated and discussed.
