Tsis zoo li qhov cub zoo tib yam, tawg- pov thawj kom qhuav qhov cub muaj qhov xav tau ntau dua rau kev tsim qauv kev nyab xeeb. Lub qhov cub hluav taws xob tsis tuaj yeem hloov pauv tau thaum ziab qee yam khoom uas muaj cov kuab tshuaj organic lossis thaum tshem tawm cov feem me me ntawm cov khoom hnyav uas siv cov txheej txheem fractional distillation.
Qhov flammability ntawm cov organic tebchaw yuav tsum tau txiav txim siab nyob rau hauv tawg - pov thawj tsim ntawm ziab qhov cub.
Roj av, cawv, toluene, thiab xim yog tag nrho cov organic tebchaw. Qhov sib txawv nyob rau hauv cov cawv thiab toluene feem ntau yog tsim los ntawm ib hom hydrocarbon, nrog rau lub cev yooj yim. Roj av thiab xim, ntawm qhov tod tes, feem ntau yog tsim los ntawm ib txwm thiab isomers ntawm ntau yam hydrocarbons thiab lwm yam tsis yog -hydrocarbon impurities, uas ua rau lub cev muaj zog. Txawm li cas los xij, lawv qhia cov yam ntxwv hauv qab no:
1. Flammable.
2. Muaj peev xwm yaj lwm yam organic tshuaj.
3. Tsis muaj zog.
4. Cov vapor ntawm feem ntau cov organic tebchaw yog denser tshaj huab cua.
Vim cov roj av thiab cov xim yog cov sib xyaw ntawm ntau yam hydrocarbons, ua ntej mus txog lawv qhov chaw qhuav distillation (kub), raws li qhov kub thiab txias, cov khoom uas muaj qhov kub thiab txias yuav evaporate rau hauv cov pa roj ua ntej, kom txog rau thaum lub distillation qhuav. Yog li ntawd, rau cov hom ntawm cov organic tebchaw, ib qho chaw txaus ntshai ib txwm muaj nyob rau hauv lub qhov cub kom txog rau thaum qhov kub txog qhov qhuav distillation point. Tsis zoo li cov cawv yooj yim thiab toluene, uas tuaj yeem evaporate tag nrho thaum lub evaporation kub mus txog, cov tebchaw no yuav tsum tau lub sij hawm ntawm qhov kub thiab txias.