Synthesis and application of thiocarbamates obtained by oxidative treatment of waste xanthate

Abstract

In this paper, the optimal treatment of industrial waste consisting from xanthate and oxidation product, i.e. diisobutyl and diethyl dixanthogenate, was developed for production of flotoreagents. Waste dixanthogenate was generated during production and storage of flotation agents, i.e. potassium isobutyl (KiBuX) and potassium ethyl xanthate (KEtX), respectively. The process of waste xanthate treatment is based on the reaction of the nucleophilic heterolysis of the persulfide bond in the diisobutyl dixanthogenates by alkylamines in presence of various oxidizing agents (sodium hypochlorite, hydrogen peroxide, potassium persulfate) to produce N-alkyl-, N,N-dialkyl- and N cycloalkyl-O-isobutyl thiocarbamate selective flotoreagents. Also, analogous methodology was applied for synthesis of N-alkyl and N,N-dialkyl-O-ethyl thiocarbamate from KetX using sodium hypochlorite at laboratory and semi-industrial level. The developed method provides the corresponding alkyl thiocarbamates in a high yield and purity. The flotation efficiency was analysed using the obtained thiocarbamate on a real sample of minerals in laboratory and industrial conditions.