Gather appropriate lab equipment and… the Field Leaders Reaction Course lab. This was done in the hopes of having enough material to generate acetylferrocene crystals later on in step 9. During this experiment, two equivalents of t-butyl alcohol were actually used to encourage disubstitution. Solvent is made using 30mL of toluene and 1mL of ethanol. It has widespread applications in the organic synthetic lab because of its efficiency for separating and purifying components of a mixture.
Once the group had made a tentative plan we scheduled a time to conduct reconnaissance of the Field Leaders Reaction Course area. The reaction involves the substitution of hydrogen on the aromatic ring system by an electrophilic carbon species forming a new carbon-carbon bond. The Friedel-Crafts acylation reaction of ferrocene involves the addition of the acylium cation to one of the carbon atoms on the ring, followed by loss of a proton to solvent. Thus, it could then be seen that phosphoric acid had aided acetic anhydride in adding a carbonyl group to the crude ferrocene, thus forming acetylferrocene. The reaction time of this experiment is reduced to limit the formation of 1,1-diacetylferrocene. Chromatography takes advantage of the differences in polarity and binding strength that the components of a mixture have for column adsorbents. Thus, it could then be seen that phosphoric acid had aided acetic anhydride in adding a carbonyl group to the crude ferrocene, thus forming acetylferrocene.
The reaction will occur via the Friedel-Crafts alkylation mechanism, and involves the attack of the aryl group at the electrophilic trimethylcarbocation. Definition: The rate of a chemical reaction is defined as the change in the concentration of one of the reactants or products in unit time. Pour the reaction onto 25g of ice in a 200mL beaker. Provide as much detail as you can about the procedure you propose to use e. Your Rf values appear to be miscalculated. This adhesiveness to the paper meant some solid product was lost from the transfer step onward.
Decant the dark-orange solution into a new Erlenmeyer flask, leaving behind the black gummy substance. The melting range for the product was taken and found to be 84. Entries 4 and 5 are critical for the catalytic performance in this reaction. The use of imino derivatives of glyoxylates as electrophiles in aza-Friedel—Crafts reaction afforded the corresponding 3-indolyl glycine derivatives, an important class of nonproteinogenic amino acids useful for synthetic intermediates and building blocks for natural products such as dragmacidins. Stir the orange-brown mixture with a glass rod for a few minutes.
Note that reaction mixture darkens in color as it heats up. Remove the solvent liquid layer using a glass Pasteur pipet with a. Adsorbents are high surface area stationary phase materials that bind solute molecules. This was lower due to the fact that many of the crystals remained stuck in the Pasteur pipet during removal of the solvents, and there may have possibly been crystals lost when removing them from the funnel for weighing, etc. In step 7 of the workup and the purification portion of the lab, almost all of the solution was boiled off.
The runoff from step 6 had to be collected, and substituted for the solution in step 7. There were multiple opportunities when crystals may have been lost. Swirl flask in hot water bath until all ferrocene is dissolved. On a small scale, column chromatography is fast and cost effective. From here, a melting point range of 147. The percent yield was 31.
Then carefully add solid sodium bicarbonate in small portions until the remaining acid has been neutralized. Boil for 5 minutes with stirring, do not over boil. The effect of catalyst structure on the reaction outcome was first investigated at 10 mol% catalyst loading in toluene Table 1, Entries 1—5. Prepare a hot water bath, heat water to nearly boiling while preparing the reaction mixture. This may be due to impuri ties in the product or the sam ple may still have been wet.
A mobile phase solvent, or eluent, is used to desorb solute molecules, carrying them along the column to a receiving flask. The first step of Friedel-Crafts alkylation requires the generation of an intermediate carbocation to act as the electrophile during the aromatic substitution process. In order to generate the electrophilic carbocation, t-butyl alcohol was treated with concentrated sulfuric acid. Throughout the lab, several errors occurred. Preliminary:… We were further interested to elaborate our catalytic conditions to the Friedel-Crafts reaction of indoles with α-amido sulfone 8 as a precursor of N-Boc α-imino ethyl glyoxylate.