Diester Disulphide Urea Synthesis And Performance Studies

Based on the existing synthesis methods of a thiourea and its derivatives, a novel thiourea, oxydiethylenedioxycarbonyl bis(N-alkyl thiourea) is synthesized by phase transfer catalysis in this thesis. The synthesis technology of the novel thiourea studied, its interaction with metal ion, and its adsorption on the mineral surface have been investigated in the paper.Using triphosgene and diethylene glycol as reactants, and N,N-dimethylformamide as a catalyst, an oxydiethylene bis(chloroformate) is synthesized. And, using oxydiethylene bis(chloroformate) prepared and KSCN as reactants, N,N-Dimethylaniline as a catalyst, an oxydiethylenedioxycarbonyl bis(isothiocyanate) intermediate is synthesized through a phase transfer catalytic reaction. Then, an organic amine is added to the mixture containing the bisisothiocyanate intermediate to prepare an oxydiethylenedioxycarbonyl bis(N-alkyl thiourea) product by an addition reaction. The preferred synthesis parameters for the phase transfer catalysis are as follows:the molar ratio of oxydiethylene bis(chloroformate) to KSCN is 1:2.5, the amount of catalyst to the bischloroformate is 6%, the react time is 2.5 hours. Based on the amount of oxydiethylene bis(chloroformate), the preferred amount of amines for the addition reaction is 2.2 for ethylamine with a 92.00% yield of oxydiethylenedioxycarbonyl bis(N-ethyl thiourea),3.0 for propylamine with a 86.65% yield of oxydiethylenedioxycarbonyl bis(N-propyl thiourea), and 2.8 for both methylamine and ethanolamine with the 87.97% and 86.95% yields of oxydiethylenedioxycarbonyl bis(N-methyl thiourea) and oxydiethylenedioxycarbonyl bis(N-hydroxyethyl thiourea), respectively. Moreover, these prepared oxydiethylenedioxycarbonyl bis(N-alkyl thioureas) have been purified, then charaterized by UV, IR spectrum, mass spectrum, elemental analysis, NMR and TG.The interactions between oxydiethylenedioxycarbonyl bis(N-alkyl thioureas) and metal ions are systemically studied. The results show that oxydiethylenedioxycarbonyl bis(N-ethyl thiourea) or oxydiethylenedioxycarbonyl bis(N-propyl thiourea) can chemically react with Cu2+ or Ag+ ions in the aqueous solution, their reactive complexes can settle down from solution in the form of sediment, and the characteristic UV absorption peak of oxydiethylenedioxycarbonyl bis(N-ethyl thiourea) or oxydiethylenedioxycarbonyl bis(N-propyl thiourea) in the reacted solution disappears. While under the same conditions, no reaction is observed when the two bisthioureas mix with Fe2+,Fe3+,Zn2+,Ni2+,Co2+ or Pb2+ ions, the characteristics UV absorption peak of the two bisthioureas in the mixture solution dereased slightly, and no sediment is observed to settle down. This fully explains that oxydiethylenedioxycarbonyl bis(N-alkyl thiourea) has favourably selective bonding ability to Cu2+ or Ag+ ions. The adsorption behavior of oxydiethylenedioxycarbonyl bis(N-alkyl thioureas) on the surfaces of chalcopyrite is investigated by Infrared Spectroscopy and total nitrogen mensuration. The results show that oxydiethylenedioxycarbonyl bis(N-ethyl thiourea) has greater adsorption capacity on the chalcopyrite surfaces than oxydiethylenedioxycarbonyl bis(N-propyl thiourea). For both of them, the adsorption capability is in proportion to the initial concentration of the two bisthioureas, and the maximum adsorption reaches at pH 6-8. Infrared spectrum futher confirm that oxydiethylenedioxycarbonyl bis(N-alkyl thioureas) can chemically adsorb on the chalcopyrite surfaces.