A Polarographic Study of Organic Peroxides

Abstract

An improved procedure is outlined for the polarographic study of organic peroxides in a nonaqueous electrolyte solution. Polarograms were observed for 23 commercial organic peroxide compounds having the following functional peroxide groups: hydroperoxides, peroxy acids, peroxyesters, six-membered bicydic peroxides, diacyl peroxides, other diacyl peroxides, and ketone peroxides. Twenty-one of the compounds showed one or more characteristic reduction waves; they were placed in five groups based on different half-wave potentials.A linear relationship existed between diffusion current and concentration for all of the peroxides investigated

Generation of acyloxyl spin adducts from N-tert-butyl-α-phenylnitrone † (PBN) and 4,5-dihydro-5,5-dimethylpyrrole 1-oxide (DMPO) via nonconventional mechanisms

“…(1)], 1f reacted with formation of two spin adducts, of which one was assigned to the acyloxyl type and the second one to the alkoxyl type. Separately, it was shown that a few alcohols (19)(20)(21)(22), including methyl benzilate 20, undergo the same type of reaction (Table 2) under similar conditions.…”

“…The reaction between dibenzoyl peroxide and PBN is known to give PhCOO-PBN ؒ in a thermal reaction, assumed to proceed by homolysis of the O᎐O bond of the peroxide and trapping of the benzoyloxyl radical by PBN. 4 However, since dibenzoyl peroxide is a weak electron transfer (ET) oxidant {it has a thermochemically estimated EЊ[(PhCOO) 2 /(PhCOO ؒ PhCOO Ϫ )] of 0.6 V in water and Ϫ0.2 V in a solvent like acetonitrile; 19 a kinetic study of the reaction between dibenzoyl peroxide and a series of hydroquinones in acetonitrile, 20 in combination with the Marcus theory, gave EЊ[(PhCOO) 2 /(PhCOO ؒ PhCOO Ϫ )] = Ϫ0.17 V; an irreversible reduction potential of Ϫ0.1 V in benzene-methanol has been determined; 21 see also below} and is likely to contain and/or form small amounts of benzoic acid or peroxybenzoic acid upon dissolution, it cannot be excluded that the HA catalysed mechanism [eqns. (3)-( 5), with HA = PhCOOH and/or PhCO 3 H and Ox = (PhCOO) 2 ] is the pathway for formation of PhCOO-PBN ؒ .…”

“…Hfs constants for spin adducts formed in the reaction between PBN and ROH(19)(20)(21)(22) in dichloromethane in the presence of 2 ϩ BF 4 Ϫ under LLE conditions or with irradiation by light of λ > 400 nm. For pK values, see ref 33.…”

High-performance liquid chromatography of selected organic peroxides with oxidative amperometric detection

“…In seeking to obtain information with regard to understanding the mechanisms associated with the ozonation process and formation of organic peroxides, and to develop sensitive and selective methods for this purpose, the approach has been to investigate the utility of electrochemical based techniques, as detection procedures, in conjunction with chromatographic methods of analysis. The literature contains little information with regard to determining organic peroxides using electrochemical based techniques except for polarographic (dc), [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] biamperometric (or dead stop end-point), 23,24 coulometric (controlled-potential), 25 etc., techniques employed more than a quarter century earlier. The high-performance liquid chromatographic (HPLC) determination of organic peroxides and hydroperoxides has been performed with various spectroscopic modes of detection such as UV, [26][27][28][29][30][31][32] IR, 30 NMR, 30 mass spectrometric 30 and chemiluminescence.…”

Polarography of conjugated unsaturated lipids

“…In neutral solvent the log of the conjugated double bonds versus the half-wave potential (versus mercury pool anode) gave a linear equation, E~ = 2.98 --1.6 log C. A proposed mechanism for the step-wise reduction of conjugated lipids is presented and discussed. polar and nonpolar solvents and a suitable supporting electrolyte, organic polarography has been extended to lipid studies to include both triglyceride and organic peroxides (1,2), steroid (3), and some 'fat-soluble vitamins (4)(5)(6).…”