1
|
Merits of online electrochemistry liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS). Anal Bioanal Chem 2016; 408:2227-38. [DOI: 10.1007/s00216-015-9246-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/25/2015] [Accepted: 12/02/2015] [Indexed: 12/11/2022]
|
2
|
Kinetics and Mechanism of the Heterogeneous Oxidation of N-Substituted-p-Phenylenediamines over Supported Zinc Oxide. Z PHYS CHEM 2002. [DOI: 10.1524/zpch.2002.216.2.249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The kinetics and mechanism of the oxidation of some N-substituted-p-phenylenediamines over ZnO supported with some transition metal sulfates were investigated at 25 °C. The rate of reaction decreased in the following order; N,N,N´,N´-tetramethyl-p-phenylenediamine, TMPPD > N,N-diethyl-p-phenylenediamine, DEPPD > N,N-di-methyl-p-phenylenediamine, DMPPD, due to the positive inductive effect of alkyl groups. For the oxidation of DEPPD, the rate of reaction was observed to have the order: Cu(II) > Fe(III) > Ni(II) > Cr(III) > Mn(II) > Co(II). The initial rate of reaction was decreased with decreasing pH as a result of the protonation of the diamine nitrogen atoms. Also, it follows a first order dependence of the initial concentration of the diamine and attained a maximum at higher concentrations. Moreover, it increased with increasing amount of the oxidant. Greater amounts, however, reduced the rate of reaction as a result of the adsorption of the formed p-semiquinonediimine, S
Collapse
|