Qhov sib txawv tseem ceeb ntawm cov khoom siv hluav taws xob thiab qhov yooj yim distillation yog cov fractional distillation yog siv thaum cov khoom hauv qhov sib tov muaj cov ntsiab lus kub dua, thaum cov khoom siv hluav taws xob yooj yim siv thaum cov khoom sib xyaw ua ke muaj qhov sib txawv loj hauv lawv cov ntsiab lus kub.
Distillation yog ib txoj kev sib cais lub cev uas yog siv los cais cov tebchaw los ntawm kev sib tov. Nws yog nyob ntawm qhov kub ntawm cov ntsiab lus ntawm cov khoom sib xyaw. Thaum sib tov muaj cov khoom sib txawv nrog cov ntsiab lus sib txawv, lawv evaporate ntawm lub sijhawm sib txawv thaum rhuab. Txoj cai no yog siv rau hauv cov txheej txheem distillation. Xav tias muaj ob yam khoom A thiab B hauv qhov sib tov, thiab A muaj qhov kub siab dua. Nyob rau hauv tas li ntawd, thaum boiling, A yuav evaporate qeeb dua B; Yog li ntawd, cov vapor yuav muaj ntau dua B dua li A. Ntawm no, qhov kev faib ua feem ntawm A thiab B nyob rau theem vapor yog qhov sib txawv ntawm qhov kev faib ua feem hauv cov kua sib tov. Los ntawm qhov no, peb tuaj yeem ncav cuag qhov kev txiav txim siab tias cov tshuaj tsis haum tshuaj feem ntau yuav raug cais tawm ntawm qhov sib xyaw thawj zaug, qhov tsis muaj tshuaj lom tsawg yuav nyob hauv qhov sib xyaw qub.
Dab tsi yooj yim yog dab tsi?
Yooj yim distillation tuaj yeem nqa tawm hauv chav kuaj. Thaum npaj ib lub cuab yeej, ib lub khob hauv qab yuav tsum tau txuas nrog ib kem. Qhov kawg ntawm kem txuas nrog lub condenser thiab dej txias yuav tsum tau nyob hauv lub condenser kom thaum vapor mus los ntawm lub condenser nws tau txias. Dej yuav tsum taug kev nyob rau hauv qhov opposite direction ntawm lub vapor, thiab uas tso cai rau siab tshaj efficiency. Qhov kawg qhib ntawm lub condenser yog txuas nrog lub hwj. Tag nrho cov cuab yeej yuav tsum tau muab tso rau hauv huab cua kom lub vapor yuav tsis khiav thaum lub sij hawm txheej txheem. Lub tshuab cua sov tuaj yeem siv los muab cov cua sov rau lub khob hauv qab, uas muaj cov sib tov sib cais. Thaum cua sov, cov vapor txav mus rau sab thiab nkag mus rau hauv lub condenser. Thaum nws mus rau hauv lub condenser, nws yuav txias thiab liquefies. Cov kua no tau sau rau hauv lub khob ntim rau ntawm qhov kawg ntawm lub condenser.
Nyob rau hauv txoj kev no, cov vapor uas tsim ncaj qha mus rau hauv lub condenser yam tsis tau taug kev los ntawm kab siab. Yog li ntawd, condensation tshwm sim sai heev. Txawm li cas los xij, txoj kev no yuav muaj qhov tsis zoo ntawm kev tsim cov distillate nrog tsawg purity. Txij li thaum tag nrho cov volatile tebchaw yuav evaporate thaum tshav kub yog muab, lub vapor yuav muaj ib tug sib tov ntawm volatile tebchaw. Qhov piv ntawm cov tebchaw hauv qhov sib tov tuaj yeem txiav txim siab raws li lawv qhov sib piv hauv thawj qhov sib xyaw. Raws li Raoult txoj cai, qhov sib xyaw ua ke yuav zoo ib yam rau cov vapors ntawm qhov muab kub thiab siab.
Yog tias peb xav kom tau txais kev sib cais zoo hauv txoj kev yooj yim distillation, nws yog qhov zoo los siv cov sib tov uas muaj cov ntsiab lus kub sib txawv. Yog tias tsis yog, cov khoom hauv qhov sib tov yuav tsum tsis yog-volatile (khoom) tshwj tsis yog qhov peb xav tau cais. Nyob rau hauv rooj plaub no, tsuas yog lub hom phiaj yuav evaporate thiab cais tawm purely.
Fractional Distillation yog dab tsi?
Thaum cov khoom hauv qhov sib tov muaj cov ntsiab lus kub dua, peb tuaj yeem siv cov txheej txheem fractional distillation los cais lawv tawm. Ib kab fractional yog siv rau hauv txoj kev no. Nyob rau hauv txhua theem ntawm cov fractionating kem, qhov kub thiab txias yuav txawv, yog li cov khoom uas muaj feem xyuam rau qhov kub thiab txias yuav nyob twj ywm rau hauv seem li vapor thaum lwm tus yog condensed rov qab mus rau lub round hauv qab khob.
Nws tseem ceeb heev uas yuav tsum nco ntsoov tias cov khoom yuav tsum yog miscible rau cov feem ntau distillation kom ua tau zoo. Ntxiv mus, fractional distillation yog txoj kev siv los ntxuav cov roj crude rau hauv ntau yam khoom.
Qhov txawv ntawm Fractional thiab Simple Distillation yog dab tsi?
Nyob rau hauv fractional distillation txoj kev, ib kab fractionating yog siv nyob rau hauv sib piv rau yooj yim distillation. Thaum cov khoom sib xyaw ua ke muaj cov ntsiab lus kub kub, fractional distillation yog siv. Thaum lawv muaj qhov sib txawv loj hauv lawv cov ntsiab lus boiling, yooj yim distillation yuav siv tau. Tsis tas li ntawd, Raoult txoj cai tuaj yeem tsis quav ntsej hauv qhov yooj yim distillation tab sis, hauv fractional distillation, nws raug txiav txim siab.
Summary – Fractional vs Simple Distillation
Qhov sib txawv tseem ceeb ntawm kev faib tawm thiab yooj yim distillation yog txoj kev faib cov fractional distillation yog siv thaum cov khoom hauv qhov sib tov muaj cov ntsiab lus kub dua, thaum cov khoom siv sib xyaw yooj yim siv thaum cov khoom sib xyaw ua ke muaj qhov sib txawv loj hauv lawv cov ntsiab lus kub..
Image Courtesy:
1. “Fractional distillation lab apparatus” Los ntawm Original: Theresa knott (tham · contribs)Derivative work: John Kershaw (tham · contribs) – File: Fractional distillation lab apparatus-p.webp
2. "Yooj yim distillation apparatus" Los ntawm Thawj-p.webp
