Distillation Principple of Chemical Reagents

Lub hom phiaj tseem ceeb ntawm distillation yog cais cov volatile thiab semi-volatile impurities los ntawm cov tshuaj reagents uas muaj impurities los yog kom evaporate volatile thiab semi-volatile tshuaj, tawm hauv tsis-volatile thiab nyuaj-rau-volatile impurities. Qhov kev hloov pauv hauv cov pa saturated vapor siab ntawm ib yam khoom ntawm qhov kub sib txawv yog lub hauv paus ntawm kev sib cais distillation. Feem ntau, yog hais tias lub vapor pressures ntawm ob lub Cheebtsam nyob rau hauv cov kua sib tov sib txawv heev, ntau volatile thiab semi-volatile Cheebtsam nyob rau hauv lub vapor theem yuav enriched. Ob theem-theem ua kua thiab theem vapor-tuaj yeem rov qab tau sib cais, thiab cov khoom tsis zoo thiab ib nrab-volatile yog concentrated nyob rau hauv cov roj theem thiab cov tsis-volatile Cheebtsam yog concentrated nyob rau hauv cov kua theem.

Ntxiv nrog rau cov khoom sib xyaw hydrocarbon thiab ob peb lwm cov piv txwv, Raoult' txoj cai lij choj thiab Dalton' txoj cai lij choj tuaj yeem siv rau cov txheej txheem sib tov zoo, thiab cov kev daws teeb meem feem ntau tsis ua raws li qhov zoo tshaj plaws vapor theem- kua theem cwj pwm. Los ntawm kev siv ob txoj cai no, qhov tshwj xeeb volatility (aAB) ntawm ob lub ntsiab lus ntawm binary system tuaj yeem tau txais: aAB=(YA / YB) / (XA / XB)=P0A / P0B qhov twg YA thiab YB yog qhov sib npaug. mole feem ntawm Cheebtsam A thiab B nyob rau hauv lub roj theem, XA thiab XB yog cov mole feem ntawm Cheebtsam A thiab B nyob rau hauv cov kua theem ntawm equilibrium, thiab P0A thiab P0B yog cov vapor pressures ntawm Cheebtsam A thiab B ntawm equilibrium, tag nrho cov mloog Raouilt's law. Raws li aAB nce, qib ntawm kev nplua nuj kuj nce.