Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.41, No.4, 464-470, 2003
Methylphosphonicdifluoride의 가수분해 및 가수분해 생성물로부터 HF의 회수 연구
Study on the Hydrolysis of Methylphosphonicdifluoride and HF Recovery from the Hydrolysate
Methylphosphonicdifluoride(DF)의 최적 가수분해 조건을 찾기 위하여 염기성 및 중성 수용액에서 가수분해하고 가수분해 생성물로부터 F 화합물을 분리, 회수하였다. DF는 NaOH 수용액의 농도 6 mole, [OH]/[DF]의 비율 4 이상에서 5분 내에 80%가 분해된 반면, 중성 수용액에서는 H2O/DF의 부피 비 1.5 이상에서 93-97%의 분해율을 보였다. 가수분해 후 생성물중의 HF를 분리하기 위하여 수산화칼슘을 사용하였으나 생성입자의 크기가 매우 작고 겔 상태로 존재하여 HF의 완전분리가 곤란하였다. 반면, 중성 수용액에서 가수분해한 DF의 생성물은 MPA, HF 및 미량의 methylphosphonofluoridic acid(MF)가 존재하였다. MPA는 휘발성이 없는 흡습성 고체이고 HF는 물과 공비점을 형성하므로 물을 주기적으로 반응기에 공급하면서 반복 증류하여 HF를 용이하게 분리할 수 있었다. 가수분해 생성물을 증류 한 결과 최대 99.7%의 F 이온을 분리하였으며 증류 후 회수된 불산의 최종 농도는 20% 이었다.
The hydrolysis of methylphosphonicdifluoride (DF) both in NaOH solutions and neutral waters was studied to find optimum reaction conditions. Separation of F ions from the reaction products was also conducted. The destruction efficiency of DF in NaOH solutions was above 80% in five minutes at the mole ratio of [OH]/[DF] 3-6, while the efficiency of 93-97% was obtained in water when the the volume ratio of the H2O/MPD was above 1.5. Ca(OH)2 was added to to remove HF in the product solutions after DF hydrolysis in alkaline solutions but it was not easy to remove due to coagulation of the products. On the other hand, HF was easily separated by repeated distillation adding water periodically to the reactor from the reaction products of DF hydrolysis in water. 99.7% of the total fluoride ions were removed from the products by repeated distillation. The final concentration of HF solution recovered was 20 wt%.
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