New method for synthesis of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropylthiocarbamates by oxidation of ammonium salt of xhantogenic acid

Abstract

Syntheses of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates by oxidation of ammonium salts of ethyl- and isopropylxanthogenic acid in the presence of sodium hypochlorite and hydrogen peroxide were performed. Ammonium salts of ethyl - and isopropylxanthogenic acid was obtained by the reaction of alkylammonium sulfate and sodium ethyl and isopropyl xanthate. Dependence of N-ethyl-O-isopropylthiocarbamate yield and purity with respect to reaction parameters (reaction time, molar ratio of oxidant and ethylamonium salt of isopropylxanthogenic acid) were studied. Optimal reaction conditions for synthesis of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates were established. The synthesized compounds have been fully characterized by FTIR, 1H-NMR and MS data, while purities have been determined by GC method. A plausible pathway for the N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates synthesis in the presence of the oxidative agents sodium hypochlorite and hydrogen peroxide was proposed. The presented synthetic method has been developed at laboratory and applied at semi-industrial level. The developed optimal method provides a powerful and versatile means for the preparation of N-alkyl and N,N-dialkyl- O-ethyl and O-isopropyl thiocarbamates, offering several benefits, namely, simple operation, mild reaction conditions, bypass of hazardous organic solvents, moderately toxic and inexpensive reagents, and also short reaction times and high product yields.

U ovom radu prikazana je sinteza, novim optimizovanim postupkom, N-alkil - i N,N-dialkil- O-etil- i O-izopropiltiokarbamata oksidacijom aminskih soli etil- i izopropilksantogene kiseline pomoću natrijum-hipohlorita i vodonik-peroksida. Alkilaminske soli etil- i izopropilksantogene kiseline dobijene su reakcijom između alkilamonijumsulfata i natrijum-etilksantata ili natrijum-izopropilksantata. Struktura sintetisanih jedinjenja potvrđena je IR, 1H-NMR i MS instrumentalnim metodama, a čistoća je određena gasnom hromatografskom metodom. Postupak sinteze opisan u ovom radu daje velike prednosti u odnosu na poznate postupke sinteze koji se primenjuju u laboratoriji i u industrijskim uslovima. Postupak karakteriše visok stepen konverzije reaktanata u proizvod, visok stepen čistoće, bez sporednih proizvoda, a tehnološki je primenljiv na industrijskom nivou proizvodnje. Sintetisana jedinjenja se primenjuju kao selektivni reagensi za flotaciju ruda bakra i cinka.