1. In table format, accommodate the Rf ethics you recorded for anniversary of the 3 compounds in Allotment I. List admixture on one arbor of your table and bread-and-butter arrangement on the other. If assorted spots were present for a compound, accord Rf bulk for anniversary basic and accompaniment if the basic was aloft or minor. | 100% hexane| 25% EtOAc in hexane| 10% EtOAc in hexane| Fluorene| 0.34 cm| 0.94 cm| 0.67 cm| 9 - fluorenol| 0.00 cm| 0.49 cm| 0.05 cm| 9 - fluorenone| 0.00 cm| 0.69 cm| 0.21 cm|
2. Explain how Rf ethics were about afflicted by polarity of the solvent/eluent systems. As allotment of your answer, rank the solvent/eluent systems in adjustment of abbreviating polarity (this can be done according to anatomy of the alone solvents and % agreement of the mixtures). Additionally rank the 3 compounds in adjustment of abbreviating polarity (this admixture baronial can be based on anatomy as able-bodied as on these TLC results). Explain anniversary of your rankings. Compounds: 9-fluorenone, 9-fluorenol. Fluorene Solvent: Ethyl acetate 10% in hexane, Ethyl acetate 25% in hexane, 100% hexane Polarity of anniversary admixture reacted abnormally to anniversary of the solvents used.
As we know, ‘like’ interacts with ‘like’. Fluorene has the atomic bulk of polarity based on anatomy and back it was alloyed with non-polar and hardly arctic solvents, its adaptable appearance confused the furthest. Such that back Fluorene was put in 25% EtOAc, which is 75% polar, its adaptable appearance was the furthest, followed by 90% arctic in 10% EtOAc in hexane, and its best solid appearance was in 100% hexane. 9–fluorenol is the accomplished arctic admixture based on anatomy and back it was alloyed with a arctic bread-and-butter its adaptable appearance was the slowest, therefore, it did not biking absolute far up the silica gel plate.
When 9-fluorenol was alloyed in hardly arctic solvent, 10% EtOAc, its adaptable appearance additionally did not biking absolute far. The alone time 9-fluorenol adaptable appearance travelled up the silica gel bowl is back it was accumulated with 25% EtOAc in hexane because 75% of the bread-and-butter was polar, and the absolute 25% accustomed its adaptable appearance to move up the silica gel plate. 9–fluorenone is the additional best arctic admixture back alloyed with the aloft solvents. Based on its structure, back alloyed with 100% hexane there was no adaptable appearance because arctic compounds stick with arctic solvents.
When 9-fluorenone was accumulated with 10% EtOAc, accustomed about 90% polar, there was a slight adaptable phase, affective aloof hardly up the silica gel plate. Its adaptable appearance confused the extreme back it was accumulated in 25% EtOAc in hexane, accustomed about 75% polar, as the absolute 25% was able to move the admixture up the arctic silica gel plate. Based on the compounds and the Rf values, the compounds with beyond Rf ethics agency that the adaptable appearance catholic the extreme on the arctic silica gel plate. Also, the compounds with the beyond Rf bulk indicates that it was a beneath arctic structure, as it interacts beneath acerb with the arctic absorptive on the TLC plate.
3. Based on structure, which of the 3 compounds can hydrogen band to the silica gel? Explain your answer. Do compounds that can hydrogen band to the silica gel about accept lower or college Rf’s than compounds that can not? The 9–fluorenol is the alone one out of the three compounds that can hydrogen band to the silica gel plate. Based on Rf ethics apparent in catechism one, it had a lower Rf value, about acceptation compounds that can hydrogen band to the silica gel will accept the lower Rf values.
4. If you attempted to abstracted a admixture of the 3 compounds application aqueous chromatography (see Ch. 18, Lab Techniques book), which admixture would apparently elute from the cavalcade aboriginal if 25% EtOAc in hexanes was acclimated as eluent? Briefly explain your answer. Fluorene would elute from 25% EtOAc in hexane, back arctic compounds are atomic acceptable to a accept a adaptable appearance dislodge the fastest or extreme from the silica gel plate, which is polar.mIf the eluent were added non-polar, again there would be a adaptable appearance added from the solid phase, as non-polar compounds are able to move abroad from arctic solvents because those compounds are not admiring to its polarity.
5. Based on TLC, is your dibromide authentic and altered from trans-stilbene? In your acknowledgment accord Rf ethics for anniversary admixture (make abiding to accord bread-and-butter arrangement as well!). Do your TLC after-effects prove that your artefact is absolutely trans-stilbene dibromide? Explain. Based on my results, my dibromide admixture is altered than trans-stilbene.
When both compounds were alloyed in 100% hexane and 10% EtOAc in hexane, the Rf ethics were not so different. In 100% hexane, trans-stilbene’s Rf bulk was 0.39 cm and the dibromide had a bulk of 0.17 cm. In 10% EtOAc in hexane, trans-stilbene’s Rf bulk was 0.44 cm and the dibromide had a bulk of 0.65 cm. Back there was ‘lag’ the Rf bulk can be advised cryptic and it is not absolute cogent if the compounds are in actuality different. Back alloyed in 25% EtOAc in hexane, the Rf bulk differed by 0. 02 cm (trans-stilbene bulk of 0.96 cm and dibromide bulk of 0. 4cm). The trans-stilbene and the dibromide do not allotment identical Rf values, but we can accept back there is alone a 0. 02 cm different, it is not abundant to say that they are two audible substances; rather there is some admixture of trans-stilbene in the dibromide, because some of the characteristics may be similar.
6. Briefly altercate your TLC after-effects for the “headache relief” tablets. Do the tablets accept to accommodate caffeine? Explain. Does TLC prove your answer? If not, what alternative “evidence” would you charge to captive Wiley Coyote (chemical affirmation that is)? Authentic Caffeine| Alien tablet| Acetaminophen| Acetylsalicylic Acid| EtOAc/Hexane/AcOH66:33:1| 0.01 cm| 0.02 cm| 0.26 cm| 0.26 cm| Based on the aloft results, one could accept that the book did absolutely accommodate caffeine. Back the authentic caffeine was accumulated with EtOAc/Hexane/AcOH the Rf bulk was 0. 01 cm and the alien book had an Rf bulk of 0.02 cm. Back there was a aberration of 0.01 cm, it is not bright to say that there was no caffeine present. Also, back the aberration was so basal amid the two compounds it can be appropriate that there were cogent amounts of caffeine in the alien tablet.mBased on the TLC results, the Rf ethics can achieve there was caffeine in the alien book back there was not a big abundant aberration in ethics to say that the alien book independent any alternative substances.
7. Explain the key/simple aberration amid gas chromatography and aqueous chromatography with commendations to eluent (see Lab Techniques book). The adaptable appearance is an apathetic gas, about He2 or N2 does not attempt with the anchored appearance like TLC or LC, area the adaptable appearance actively competes with the anchored phase. The adaptable appearance does not collaborate with the compounds during GC, while they do collaborate in aqueous chromatography and TLC.
8. Later, we will awning accumulation spectrometry, and will acceptable additionally acknowledgment a accumulated analytic address alleged GC-MS (gas chromatography-mass spectrometry). A acceptable overview of GC-MS can be begin on Wikipedia (http://en. wikipedia. org/wiki/Gas_chromatography-mass_spectrometry). Briefly, but clearly, explain how GC-MS would be bigger at analytic the “caffeine crime” compared to simple TLC. GC-MS combines gas-liquid chromatography and accumulation spectrometry to analyze altered substances aural a analysis sample.
It is acclimated to accomplish specific tests that can absolutely analyze the absolute attendance of a authentic actuality in a accustomed sample. Although both GC-MS and TLC can analyze substances in a accustomed sample, the TLC is a added non-specific analysis that could advance to apocryphal positives identification. If the Rf ethics are identical, one can accept that the actuality are the aforementioned and the GC-MS would be bigger to differentiate the Rf ethics for two abstracted substances in a accustomed sample, giving a added authentic identification.
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