Spectroscopic Characterization of Ethyl Xanthate Oxidation Products and Analysis by Ion Interaction Chromatography

Abstract

An ion interaction chromatographic separation method, coupled with UV spectroscopic detection, has been developed for the analysis of ethyl xanthate (O-ethyl dithiocarbonate) and its oxidative decomposition products in mineral flotation systems. The effects of the ion-pairing agent (tetrabutylammonium ion), pH modifier (phosphoric acid), and organic modifier (acetonitrile) in the eluant upon the retention characteristics of the ethyl xanthate oxidation products have been determined. The optimized separation procedure has been successfully applied to the analysis of ethyl xanthate and its oxidation products in a nickel-iron sulfide mineral suspension containing a number of other anionic species, including cyanide complexes of nickel and iron, as well as sulfur-oxy anions. The ethyl xanthate oxidation products investigated in this study have been isolated as pure compounds and characterized by UV-visible, FT-IR, and NMR spectroscopies. The UV-visible and FT-IR spectroscopic properties of these species are discussed in terms of the chemical modifications of the thiocarbonate group.

Xanthates: Metabolism by Flavoprotein-Containing Monooxygenases and Antimycobacterial Activity

“…The sharper increase of perxanthate over time compared to that of ETH-S-oxide was not only due to the higher extinction coefficient of the former -ε =10,400 M -1 cm -1 (Hao et al, 2000) versus ε = 6,000 M -1 cm -1 (Vannelli et al, 2002). and EtaA enabled the direct observation and comparison of product formation and substrate consumption rates.…”

Xanthate degradation occurring in flotation process waters of a gold concentrator plant

“…The degradation chemicals were potassium ethyl thiocarbonate (KETC), ammonium ethyl perxanthate (NH 4 EPX), and tetrabutylammonium ethyl xanthyl thiosulfate (TBAEXT). They were synthesized according to the technique described by Hao et al (2000) in the laboratory of organic chemistry at Lappeenranta University of Technology (Lappeenranta, Finland). For the artificial simulation of the industrial processes, the commercial KEX was used as the starting chemical for producing the decomposition products in the laboratory.…”

“…The degradation thus decreases the recovery of metal extraction and disturbs the process productivity (Bulatovic, 2007;Yekeler and Yekeler, 2004). Usually, froth flotation occurs in the pH range 6-12 (Bulatovic, 2007), where xanthates may actively produce side-products such as dixanthogen (Eliseev, 2012), thiocarbonate (Eliseev, 2012), perxanthate (Sun and Forsling, 1997;Hao et al, 2000), and xanthyl thiosulfate (Hao et al, 2000).…”

“…In general, lack of separation is the main problem in the monitoring of xanthate processes, as the degradation of the process chemicals cannot be avoided. In such cases, to obtain reliable information, Hao et al (2000) isolated the xanthates from the process waters using a liquid-liquid extraction containing organic solvents before quantification. However, the method was time consuming, and it could not easily be coupled to the main industrial processes.…”

“…However, the method was time consuming, and it could not easily be coupled to the main industrial processes. Hao et al (2000Hao et al ( , 2008 have also previously studied ethyl xanthate, ethyl dixanthogen, ethyl thiocarbonate, ethyl perxanthate, and ethyl xanthyl thiosulfate with Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies. Conversely, Trudgett (2005) using a separation technique to ensure reliability of the identification of the by-products in the process waters (Trudgett, 2005).…”