Investigation Of The Synthesis And Performance Of Acylthioureas

Based on the available synthesis methods of acyl cloride and acyl thiourea, a series of acyl chlorides and acylthioureas were synthesised respectively by triphosgene method and phase transfer catalysis in this paper. Meanwhile, their synthesis conditions were studied. For the acylthiourea, its interaction with metal ion, adsorption on the surface of minerals and flotation performance had been investigated.Using carboxylic acid as reactants, triphosgene as acylating reagent and N,N-dimethylformamide(DMF) as a catalyst, n-butyryl chloride, n-hexanoyl chloride and n-octanoyl chloride were synthesized under sovent-free condition。The synthesis conditions of n-butyryl chloride were as follows:the reacting weight of n-butyric acid was40mmol, the molar ratio of triphosgene to n-butyric acid was1.5:3, the temperature of the reaction was55℃. the mass fraction of DMF to triphosgene was1.7%, and the time of the reaction was50minutes. The yied of n-butyryl chloride was79.64%under above conditons. While reacting at60℃, the mass fraction of DMF to triphosgene was1.8%and other conditions were as same as the n-butyryl chloride, n-hexanoyl chloride was synthesized with yied of84.90%. While the mass fraction of DMF to triphosgene was2.1%and other conditions were as same as the n-butyryl chloride, n-octanoyl chloride was synthesized with yied of68.74%. The synthesis parameters of benzoyl chloride were as follows:the reacting weight of benzoic acid was80mmol, dosage of solvent toluene was40mL, the molar ratio of triphosgene to benzoic acid was1.5:3, the reactive temperature was60℃, the amount of DMF was1.5%of the triphosgene quality and the reactive time was4hours. The yied of benzoyl chloride was78.05%under above conditions.Using acyl chlorides prepared, potassium thiocyanate and organic amine as reactants and PEG-400as a phase transfer catalyst, a series of N,N-(di-n-alkyl)-N’-n-hexanoyl (octanoyl)thioureas were prepared by one pot process, whose yied was80%～90%. The synthesis parameters were as follows:the reacting weight of acyl cloride was350mmol, the dosage of solvent dichloromethane was80mL, the molar ratio of n-hexanoyl(octanoyl) chloride, potassium thiocyanate, secondary amine and PEG-400was1:1.08:1.10:0.03; the time of substitution reaction was4hours, and2hours for addition reaction; the reactive temperature was20℃. Using similar process, N-(3-alkoxy)-propyl-N’-benzoyl thioureas were synthesized, whose synthesis parameters were as follows: the reacting weight of benzoyl chloride was150mmol, the dosage of solvent dichloromethane was80mL, the molar ratio of benzoyl chloride, potassium thiocyanate, amine and PEG-400was1:1.50:1.10:0.03; the time of substitution reaction was1hour, and1hour for addition reaction; the reactive temperature was20℃. And the yield of N-3-methoxy-propyl-N’-benzoyl thiourea was66.73%. Moreover, these acylthioureas prepared had been purified, then charaterized and confirmed by UV, IR and NMR spectrum.The interactions between acyltioureas and metal ions were studied by UV spectrum and IR spectrum. The results showed that these acylthioureas had favorably selective bonding ability to Cu and Ag. The adsorption behavior of N,N-dipropyl-N’-n-hexanoyl thiourea on the surface of chalcopyrite was investigated. The results showed that the adsorption capability was in proportion to the initial concentration of the acylthiourea, and the maximum adsorption reached at pH8～10. The results of the flotation test showed that the N-3-butoxypropyl-N’-benzoyl thiourea had good collecting ability for copper mineral.