Synthesis, Characterization And Properties Of Novel Alkoxycarbonyl Bisthioureas And Thionocarbamate Thioureas

Based on the research development of the thiourea and its derivatives, alkoxycarbonyl bisthioureas and thionocarbamate thioureas with the new structure containing two thiourea groups or thiourea、 thionocarbamate group were synthesized. The synthesis technology of the novel thiourea was studied. Meanwhile, the chelating properties of these novel collectors to mineral ions and the adsorption mechanism on monominerals were investigated. Furthermore, the performance of these novel collectors to flotation and extraction was also studied.The novel thiourea collectors were prepared by the intermediate alkoxycarbonyl isothiocyanate and the organic amine added, and the intermediate alkoxycarbonyl isothiocyanate was produced from sodium thiocyanate and chloroformate (ethyl chlorocarbonate, isobutyl chloroformate, isooctyl chloroformate) with N,N-dimethylaniline (DMA) as the catalyst. The optimal conditions to prepare N, N’-di-iso-octyl oxycarbonyl-N",N"’-(2,2’-polypropylene etheryl)-bis-thiourea (DiOPEBT U) were found as follow:mole ratio of DMA、NaSCN、poly ether amine to isooctyl chloroformate0.06:1.1:0.6:1, the reaction time and temperature for the first step were2.5h and0～5℃, respectively, the reaction time and temperature for the second step were2h and under12℃. Under these conditions, the yield of DiOPEBTU reached82.34%. As to N,N’-diethoxycarbonyl-O,N"’-(2,2’-alkylene etheryl)-thionocarbamate thiourea(DEEECTU), the optimal conditions were found as follow:mole ratio of DMA, NaSCN,2-(2-aminoethoxy)ethanol to ethyl chlorocarbomate0.08:1.1:0.6:1, the reaction time and temperature for the first step were2.5h and0～5℃and the reaction conditions for the second step were illustrated as follows:the reaction time was2h at a temperature below10℃and then2h at60℃followed by the separation of the aqueous phase. Under these conditions, the yield of DEEECTU reached90.63%. Moreover, these novel alkoxycarbonyl bisthioureas and thionocarbamate thioureas were charaterized by UV spectrum, IR spectrum and NMR. The interactions between novel alkoxycarbonyl bisthioureas and thionocarbamate thioureas and metal ions were systemically studied by ultraviolet spectroscopy combining with the effect of pH in the solutions.The results showed that Cu2+、Ag+ions can significantly reduced absorbance and pH value of the thiourea solution, while the effect with Fe2+、Fe3+、Co2+、Ni2+、Zn2+、and Pb2+was not obvious. Based on the above experimental data, a conclusion may be drawn as below:the novel alkoxycarbonyl bisthioureas and thionocarbamate thioureas could chemically react with Cu2+, Ag+except Fe2+, Fe3+, Ni2+, Co2+, Zn2+or Pb2+. The results of adsorption experiments showed the adsorption capacity of DEEECTU onto chalcopyrite surface was larger than adsorption capacity onto sphalerite and galena surface. The analysis of the adsorption thermodynamics revealed that the adsorption of DEEECTU on chalcopyrite was the chemical action.In addition, the extraction and flotation performance of alkoxycarbonyl bisthioureas and thionocarbamate thioureas were also studied.The performance of N, N’-di-isobutyloxycarbonyl-N",Nm-(1,3-propylene)-Bisthiourea (DiBPLBTU) to extract in ammonia solution was studied. The results showed that the temperature was30℃, the phase ratio of organic phases and aqueous volume was O/A=1:4, the extraction time was lOmin, the extractant concentration was200g/L, the aqueous initial pH was10, Cu2+concentration was3g/L and total ammonia was0.5mol/L, the extraction ratio of copper could be achieved98.88%. The results of the flotation test showed that N,N’-di-ethoxycarbonyl-N", N"’-(2,2’-alkylene polypropylene etheryl)-bisthiourea(DEPEBTU) and DEEECTU had good collecting ability.