Experiment 6 Lab Report PDF

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Column Chromatography Purpose: The purpose of this experiment is to separate a product from a Friedel-crafts acylation of ferrocene using column chromatography Reaction and Physical Properties Table:

Reagents and Solvents Ferrocene Acetylferrocene Diacetyl ferrocene Dichloromethane Hexane Methanol Alumina

Molecular Weight (g/mol) 186.04 228.07 270.03 84.93 86.18 32.04 101.96

Density (g/ml) 1.49 1.014 N/A 1.33 0.66 0.791 3.97

Safety: All data obtained from Thermofischer Scientific Ferrocene (Flammable) Risk Statements: flammable, harmful if swallowed. Safety Statements: Keep away from open flames. Do not inhale. Wash any exposed skin thoroughly for 15 minutes. Acetylferrocene (Irritant) Risk Statements: may cause skin burns and eye damage. May cause respiratory irritation. Safety Statements: Wear all protective clothing and use in well ventilated area. Do not breath in fumes. Diacetyl Ferrocene (Irritant) Risk Statements: may cause skin burns and eye damage. May cause respiratory irritation. Safety Statements: Wear all protective clothing and use in well ventilated area. Do not breath in fumes. Dicholormethane (Irritant) Risk Statements: may cause skin burns and eye damage. May cause respiratory irritation. Safety Statements: Wear all protective clothing and use in well ventilated area. Do not breath in fumes. Hexane (Flammable) Risk Statements: flammable, harmful if swallowed.

Safety Statements: Keep away from open flames. Do not inhale. Wash any exposed skin thoroughly for 15 minutes. Methanol (Flammable) Risk Statements: flammable, harmful if swallowed. Safety Statements: Keep away from open flames. Do not inhale. Wash any exposed skin thoroughly for 15 minutes. Alumina (Irritant) Risk Statements: may cause skin burns and eye damage. May cause respiratory irritation. Safety Statements: Wear all protective clothing and use in well ventilated area. Do not breath in fumes. Procedures: 1. Add ~1ml of CH2Cl2 to vial containing crude product from experiment 5. Use solution to spot TLC plate 2. Ferrocene should be spotted for comparison but if ferrocene not available, dissolve a bit in CH2Cl2 and spot 3. Push a piece of cotton into the bottom of the column, It needs to hold the sand and alumina in place, Do not pack very tightly. 4. Add small amounts of sand to column, add alumina to column, only need 2-3 inches of sand to funnel (2 in should be sufficient) 5. Add solution of crude product to beaker with ~0.3 alumina in small beaker and evaporate using compressed air 6. Scrape mixture from from beaker and add to top of column. 7. Should appear like this

8. Sand should be added to the top of the column after the mixture is added to minimize disruption of material when solvent is added. 9. Once solvent added to column do not let column to go dry (don’t let liquid to drop below alumina top) 10. Use hexene to elute ferrocene from the column. Keep stock cock open as add enough hexene to fill the column. A colored band should move down the column, Try to collect colored solution separately from the hexene 11. Once solution no longer colored, ferrocene eluted from column. 12. Use 1:1 mixture hexene to CH2Cl2 to elute acetylferrocene from the column. If not efficiently enough then use straight CH2Cl2 13. Remember to only collected colored band of moving down the column. Only solution no longer colored, acetylferrocene has been eluted form the column. 14. 9:1 mixture CH2Cl2OH used to elute diacetyl ferrocene from column. 15. Solvent from each colored fraction evaporated in the hood using compressed air and gentle heating.

16. Clean column using compressed air 17. IR spectrum will be obtained for ferrocene, acetylferrocene, and diacetylferrocene for each isolated product obtained by students. 18. Check each fraction by TLC to confirm purity Data/Observations: Mass of starting mixture: 0.1022g To begin, eluted with hexene to obtain ferrocene from the product Eluted with 1:1 CH2Cl2 and hexene to obtain acetylferrocene Eluted with 9:1 CH2Cl:CH3OH to obtain diacetylferrocene Mass of empty beaker: 25.5816 g Mass of beaker with solid from Fraction 1: 25.6016 g Fraction 1 was a bright yellow color in both liquid and solid Mass of empty beaker: 28.9357 g Mass of beaker with solid from Fraction 2: 29.0037 g Fraction 2 was a bright orange color in both liquid and solid Mass of empty beaker: 31.6434 g Mass of beaker with solid from Fraction 3: 31.6493 g Fraction 3 was a yellowish-orange color in both liquid and solid Fraction 1: 0.02g Fraction 2: 0.068g Fraction 3: 0.0059 g

Calculations/Results: Percent yield ferrocene:

!.!!!#!$%&'()%*+',-./ 𝑥100% !.!!!012%&'()%)/3+/456 %&3/7+43(

Percent Yield Acetylferrocene:

= 19.67%

!.!!!82$%&'()%*+',-./ 𝑥100%=66.55% !.!!!11$%&'()%)/3+/456%&3/7+43(

Percent Yield Diacetylferrocene:

!.!!!!88%&'()%*+',-./ 𝑥100% !.!!!9:$%&'()%)/3+/456%&3/7+43(

= 5.78%

Discussion/Conclusion The purpose of this lab was to isolate products from one crude product that was obtained from a previous lab. This previous lab had an impure product that contained three different compounds. These three different compounds in the product could then be isolated. Different solvents dissolve different products contained in the compound. Ferrocene was eluted by hexene, acetylferrocene by a CH2Cl2 and hexene mixture and then diacetylferrocene with CH2Cl and CH3OH mixture. In this experiment, the silica was used as the stationary phase and the solvent as the mobile phase. The experiment began with the most non-polar molecule first and then gradually increased in polarity with the different solvents used.

Post Lab Questions: 1. Rank ferrocene, acetylferrocene, and diacetylferrocene in order of increasing polarity. Do the TLC results from your fractions support this ranking? Explain. Ferrocene < Acetylferrocene < Diacetylferrocene and this was supported by the TLC plate because the highest Rf value was ferrocene and then actylferrocene and diacetylferrocene. 2. Rank the solvents used in the experiment in order of increasing polarity. hexane < 1:1 mixture of hexane: methylene chloride < 9:1 mixture of methylene chloride: hexane 3. Why do you start with the least polar solvent/solvent mixture and progress to increasing polar solvent/solvent mixtures when eluting the ferrocene compounds from the column rather than starting with more polar solvent system and progressing to less polar solvents? The silica is highly polar so beginning with non-polar solvents allows the more polar products to bind to the silica and not be eluted out of the mixture just yet 4. How do the thin layer and column chromatography for this experiment compare in regard to stationary and mobile phases? Both TLC and column chromatography have the silica gel as the stationary phase. Both also use the same kind of solvent so the results are identical. TLC works against gravity and the column works with gravity. 5. What key feature in the IR spectrum of acetylferrocene distinguishes it from the spectrum of ferrocene?’ Carbonyl stretching frequency at 1700cm-1 distinguishes the two...