Aj. Vreugdenhil et al., INFRARED SPECTROSCOPIC DETERMINATION OF THE GAS-PHASE THERMAL-DECOMPOSITION PRODUCTS OF METAL-ETHYLDITHIOCARBONATE COMPLEXES, SPECT ACT A, 53(12), 1997, pp. 2139-2151
Citations number
27
Journal title
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
Head-space analysis by gas-phase infrared spectroscopy (HAGIS) allows
the facile examination of the decomposition mechanisms of the metal xa
nthates [metal-(O-alkyldithiocarbonates], Fe(EtOCS2)(3), Zn(EtOCS2)(2)
, Cu(EtOCS2), Pb(EtOCS2)(2) and Ni(EtOCS2)(2), over the temperature ra
nge 25-120 degrees C. These metal xanthates fall into two groups based
on the generation of the primary gaseous decomposition products, CS2,
COS and CO2. The first group, consisting of Fe(III) and Zn(II) xantha
tes, decompose readily, forming mostly CS2 and COS in a constant ratio
and leaving, initially, a metal-alkoxide residue. In the second group
, decomposition is relatively small, generating CO2 and COS, with the
proportion of COS increasing as the temperature increases and CS2 form
ation occurring only at the upper end of the temperature range. The re
sidue is more of a metal-thioalkyl species in this case. Presumably, C
O2 is formed by re-insertion of COS into a metal alkoxide and eliminat
ion of CO2, leaving a thioalkyl moiety. Volatile metal-xanthates are p
robably observed in the gas-phase, allowing examination of the changes
concomitant to the vaporization of the discrete metal xanthates from
network or partially associated solids. (C) 1997 Elsevier Science B.V.