Six oligomers of -aminocaproic acid (ACA) from dimer (K2) to heptamer (K7), gamma-irradiated in an oxygen-free atmosphere, were investigated by the EPR method. The oligomers were synthesized and irradiated with60Co gamma-rays in the dose range from 0 to 6.5 kGy. The formation of –CH2–CONH–CH–CH2– radical was established. The quantitative determinations of total concentrations of spins were carried out. On the basis of the present and earlier results, the competition of the reactions of detachment of hydrogen and of breaking of –CONH– bond is discussed. The particular resistance of amide bond in dimer seems to be confirmed by the measurements of kinetics of radical decay. The mass spectrometry of gamma-unirradiated ACA and ACA oligomers K2-K4 was carried out. The results indicate a minute contribution of ionic processes in the radiolysis of ACA oligomers in solid phase.
Stable and transient products of the -radiolysis of dichloromethane (DCM) and 1,1-dichloroethane (11 DCE) have been investigated in an oxygen-free atmosphere. The stable products were separated by preparative gas chromatography and identified by NMR and mass spectroscopy. The quantitative determinations were performed by potentiometric and gas chromatographic analysis. The main products of radiolysis of DCM are dimers (11DCE, 12DCE, 112TCE, 1122TetraCE) and the product of dechlorination CM; in the case of 11DCE-dimers (133TCB, 2233TetraCB) and the product of dechlorination CE as well as products of isomerization and chlorination of the parent compound (12DCE, 112TCE). The gas products of both chlorides are HCl and H2. The ESR investigations at 77 K indicate the formation of at least two kinds of radicals in both chlorides: CH2Cl/CHCl2=1/3 in DCM and CH3CCl2/CH3CHCl=2.5/1 in 11DCE. An outline of the mechanism of radiolysis is proposed.
Authors:W. Szymanski, S. Truszkowski, G. Smietanska, and M. Kowal
The stable radiolysis products of 1-chlorobutane (1-CB), 1-chlorobutene-2 (1-CB-2), 1-chloropropane (1-CP), 2-chloropropane (2-CP) and 1,3-dichloropropane (1,3-DCP) gamma-irradiated in an oxygen-free atmosphere have been investigated. The pure radiolysis products were separated by preparative gas chromatography and identified by NMR and mass spectroscopy as well as qualitative gas chromatography. The compounds formed were determined by potentiometric analysis and quantitative gas chromatography. From 1-CB we have obtained in the gas phase: HCl, H2, butane; in the liquid phase: 2-chlorobutane, 1,3-dichlorobutane and a mixture of oligomers of the initial compound (dimer and trimer). We have not recorded H2 in 1-CB-2. The main gaseous products of radiolysis of 1-CP are HCl and H2. Radiation yield of isomerization was determined. From 2-CP we have obtained in the gas phase: HCl and H2; in the liquid phase: 2,2-dichloropropane and a mixture of oligomers of the initial compound (dimers and trimers). From 1,3-DCP we have found in the gas phase: HCl and H2; in the liquid phase: 1-CP, 2-CP, 1,2-DCP and oligomers. Preliminary schemes for the formation of stable products are proposed.