Synthesis Of Imidazolium-based Ionic Liquids And Its Application In The Preparation Of Titanium By Electro-deoxidization

Ionic liquids have the excellent performance of wide electrochemical windows,good electrical conductivity,well chemical and thermal stability and so on.It is widely used in electrochemistry,organic synthesis,extractive separation,material preparation areas and has become one of the research hotspots of green chemistry;Titanium is a kind of structural and functional material,which has a series of particular properties such as little density,high strength,corrosion resistance.It also has the function of superconductivity,hydrogen storage and shape memory etc.It has been widely used in aerospace,weaponry biomedicine and so on.But the Kroll method of producing titanium sponge has the disadvantage of process long,high energy consumption,intermittent shortcomings.The researcher has been trying to find a new production titanium method.In this article,we electrolytic titanium oxide to prepareing Ti in ionic liquid which added CaCl2 based on FFC of preparing metal titanium whih electro-deoxidization in molten salt.The main research contents are as follows:We synthesized[EMIM]BF4,[BMIM]BF4,[EMIM]PF6,[BMIM]PF6 four ionic liquids with two steps method and proofed the products with FT-IR.The optimized synthetic process is the reaction time is 24h,temperature is 70℃,molar ratio is 1:1.10 by orthogonal experiment and the productivity is 92.31%.The[BMIM]Br of microwave-assisted synthesis condition was molar ratio is 1:1.05,temperature is 70℃,power is 160W,worked 25s and suspended 10s circulation five timesThe solubility,water imbibition,density,conductivity,viscosity was measured of the four ionic liquid.The result show that:Fluorine acid-based ionic liquid is hydrophilic ionic liquid,Fluorine phosphoric acid ionic liquid is hydrophobic ionic liquid;The density of ionic liquid gradually reduced with the rise of temperature;The conductivity is gradually increasing with the rise of temperature,The smaller of the anion and the cation,the greater of the conductivity under the same tempreture;The logarithm of conductivity and viscosity with the reciprocal of tempreture is linear relation,corresponded Arrhenius formula.Thermogravimetric analysis and Electrochemical window of ionic liquids was measured:ionic liquids began to weightlessness above 300℃;The Electrochemical window of[BMIM]BF4 is widest.Cathode pressing,sintering temperature,additives was investigated to the cathode performance,The pressure of the cathode pressing,sintering temperature,the influence factors such as additive was investigated,The results show that:when the pressure is 10 MPa,sintering temperature is 1000℃ is suitable for the cathode,cathode blowhole rate reached 45%and conductivity reached to 44 mS/cm when contentd 30%carbon.Cathode sample was electrolyzed in[BMIM]BF4 ionic liquid added CaCl2.The before and after electrolysis surface morphology of the titanium dioxide,adding graphite and adding calcium carbonate cathode was studied by scanning electron microscope.The surface morphology changed was indicated that the electrolytic reaction had happened;The phase composition of electrolyted cathode pure titanium dioxide and graphite added was studied by x-ray diffraction.The best result was under the condition of adding 10%graphite,suppressing at 1OMPa,sintering at 1000℃,electrolysising at 3.0V for 10h.The thermodynamic stability of titanium oxides was studied,the low atomicity of titanium oxide stability is greater than the higher oxides.We can obtain the conclusion of preparing of titanium through electrolysis of titanium dioxide in the ionic liquid was happened by step through electrochemical method.The mechanism is TiO2→TiO→Ti,the mechanism of preparing of titanium through electrolysis of titanium dioxide was the cathodic oxygen ionization.