| As malodorous, colorless, highly toxic, carcinogenic gas, phosphine was discharged mainly in the process of production of yellow phosphorus, magnesium powder preparation, acetylene production, the sodium phosphate production, the semiconductor industry production, paddy fumigation etc.. This may cause environmental pollution, hazard human health, and restrict the production process control, safety in production and comprehensive utilization of waste. With the enhancements of the people’s environmental awareness, ionic liquid in line with the current development trend of green chemistry has aroused widespread concern. As the current purification methods of phosphine exist the difficulty in product separation even purification efficiency or catalyst regeneration, this paper explore the research of phosphine purification with ionic liquid catalytic oxidation which still had not reported home and abroad.The main goal of the research was deeply selective purification of phosphine in exhaust gas, especially phosphorus exhaust and confined calcium carbide furnace exhaust. A series of ionic liquids were prepared by double composition and characterized by FT-IR. Based on purification efficiency of phosphine, the metal-ligand ionic liquid were screened as catalyst. According to the effects of catalyst concentrations, temperature, oxygen content and other dynamic conditions on activity, stability, renewability of catalysis, the dynamic discipline of the catalytic oxidation were explored and the best catalyst with good activity and stability, easily renewability was obtained. Finally, according to the infrared spectra of catalyst solution and the solubility of PH3and O2in the catalyst, the mechanism of the ionic liquid catalytic oxidation was explored, and conclusions were as follows:(1) Ionic liquid [bmim]C1,[bmim]Br,[bmim]PF6,[bmim]BF4,[bmim][CF3COO][H3N+-CH2-CH2-OH][CH3COO],[bmim]NO3,[SO3H-bmim][HSO4],[bmim][HSO4] palladium-based ionic liquid and cuprous-based ionic liquid were prepared. The infrared characterization results show that the target ionic liquids were successfully synthesized.(2)[bmim]Br and palladium-based ionic liquid appeared weightlessness at70℃,[bmim]Cl and [bmim] PF6started to decompose at90℃, the cuprous-based ionic liquid had the best thermal stability, a slight weightlessness at180℃. (3) PH3did not show any solubility in [bmim]Br, dissolved volumes of PH3and O2in the other ionic liquids suggest that there was a gradually decreased after an increase to a high point as reactions progressed and this phenomenon repeated, except cuprous-based ionic liquid. Dissolved volume of PH3and O2in cuprous-based ionic liquid suggsted almost a linear growth as reactions progressed. The experiments showed that heating favored the dissolution of PH3and O2in the catalyst solution. The experiment also showed that the best temperature range is50℃～70℃for solubility.(4) There is no purification efficiency using single ionic liquid as catalyst, but metal-based ionic liquids demonstraded better catalytic activity on the purification of PH3, especially the palladium-based ionic liquid and cuprous-based ionic liquid,, the purification efficiency could reach90%or more at50℃.(5) Palladium-based ionic liquid catalyst system is of high stability and showed a good catalytic capacity on the oxidation of PH3. The optimum condition were:[bmim]C1/PdCl2was1:0.05, the oxygen content was7.08%, the flow rate of gas mixture was180mL/min at50℃. Under optimum conditions, purification efficiency was99%and saturated phosphorus capacity was25g PH3/L(solution). Regenerating the catalyst solution when it was inactive, and the purification efficiency of PH3could achieve99%as well, indicating that the catalyst was of good regeneration and recovery potential.(6) Cuprous-based ionic liquid catalyst system is of high stability. The optimum condition were:[bmim]Cl/CuCl was1:3, the oxygen content was7.8%and the reaction temperature was60℃. Under optimum conditions, it was100%and45gPH3/L(solution) respectively for purifying efficiency and saturated phosphorus capacity. Regenerating the catalyst solution when it was inactive, and the purification efficiency of PH3could still keep at97%for a long time, indicating that the catalyst was of good regeneration and recovery potential.(7) The mechanism of cuprous-based ionic liquid catalytic oxidation was investigated, and the results indicated a coordinated catalysis. |
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