The radical intermediate, which is produced in the process of electroless nickel plating, was detected in the presence of water-soluble trap α-4-pyridy1-N-tert-buty1 nitrone（POBN） or α-phenyl-tert-buty1 nitrone（PBN） by electron spin resonance（ESR） spectroscopy. The results obtained indicated that a 16-line（g=2.006 1, aβC—H=1.98×10-4 T, aγP—H=3.32×10-4 T, aN=aP=15.93×10-4 T） or a 18-line （g=2.004 9, aβC—H=aγP—H=2.38×10-4 T, aP=17.72×10-4 T, aN=16.20×10-4 T） ESR spectrum was observed in the process of electroless nickel plating when spin trap PBN or POBN was added. The spectra-line patterns and hyperfine coupling parameters were greatly indentical with those in the solution composed of Ti3+（0.01 mol/L）+H2O2（0.05 mol/L）+H2PO-2（0.01 mol/L）+POBN or PBN（0.01 mol/L）. Therefore, the spin adducts formed in the process of electroless nickel plating could be ascribed to the adducts belonging to HPO-·2 and POBN or PBN and it follows that the anion radical HPO-·2 was really produced from the oxidation of sodium hypophosphite in the process of electroless nickel plating.
The intermediates of electroreduction of 3 hexyne 2,5 diol at platinized platinum electrode in perchlorate aqueous solutions with various pH values have been studied by using electrochemical ESR technique with the spin trap phenyl tert butyl nitrone. The six line spectra in the three solutions with 1.5, 3.5 and 5.0 pH values could be ascribed to the form of the radicals, such as CH 3C·HC CCH 2CH 3 , in the process of producing 3 hexyne. The four line spectra, increasing in their intensities with increase in pH values from 1.5 to 5.0, show that a 2 hydroxyalkyl radical CH 3C·(OH)CH CHCH(OH)CH 3 is formed via the interaction between the atom H and intermediates 3 hexene 2,5 diol and/or CH 3C( O)·CH CHCH(OH)CH 3. [WT5HZ]
Electron spin resonance trapping technique with phenyl t-butyl nitrone (PBN)have been used to study the process of electroreduction of p-toluene sulfonamide at mercury electrode. The results showed that the reaction is a free radical one. p-toluene/benzyl radicals formed yia a stage of detaching sulfonamide group have been identified by the hyperfine spectrum of the radical adducts.
Electrochemical-ESR technique (ex situ method) with spin traps phenyl tert-butyl nitrone (PBN) and 5,5-dimethyl-1-Pyrroline-1-oxide (DMPO) has been applied to the detection of radical intermediates produced during electroreduction of propargyl alcohol (PA) at platinized platinum electrode in an acidified alcohol-aqua solution. Propargyl radical and H have been detected by PBN and DMPO, respectively. As a result of the discovery of these radicals, an evidence for a radical mechanism of the electroreduction of PA put forward by some authors might be obtained beyond all doubt.
