Abstract: The purpose of this lab was to synthesize triphenylmethanol from benzophenone and bromobenzene by the formation of a Grignard compound with the reagents bromobenzene and magnesium metal. The bromobenzene was first transformed into the Grignard compound and was then reacted with the benzophenone to make the final product. The mixture was then mixed with sulfuric acid and the organic layer was extracted via a separatory funnel. The mixture was then recrystallized from methanol and was allowed to dry and the percent yield, melting point, and the IR was obtained. The mass of the product obtained was 5.45 grams and the percentage yield was determined to be 41.95%. The melting point range obtained from the final product was 89-91°C …show more content…
5.3 mL of bromobenzne and 15 mL of anhydrous ether was then placed into the separatory funnel and was shaken and vented in order to mix the solution. Half of the bromobenzene solution was added first into the round bottom flask and as soon as a color change was observed, the remaining half of the bromobenzene was added drop wise into the round bottom flask. The mixture was then refluxed on a heating mantle for 10 minutes until most of the magnesium has been consumed. After the initial mixture has refluxed, 9.11 grams of benzophenone was dissolved in 100 mL of anhydrous ether in a beaker and was then transferred into the separatory on the reflux apparatus. This solution was then added to the Grignard reagent at a drop wise rate while stirring. After the benzophenone was added, the mixture was then refluxed for 15 minutes on a heating mantle. After the mixture finished refluxing, the flask was then cooled on ice. A sulfuric acid solution was then prepared by pouring 4.5 mL of concentrated H2SO4 over 50 grams of ice and then diluted to 75 mL by adding enough tap water to reach 75 mL. The sulfuric acid solution was then cooled on ice. The Claisen adapter was then removed from the 250 mL round bottom flask and the condenser was then attached to the top of the round bottom flask which was then put on ice. The sulfuric acid solution was then poured through the condenser in order to protonate the product. A stirring rod was then used to dislodge any solid that was stuck to
In part A, the Grignard reagent was created. Mg is added between the benzene ring and the bromine by means of a non-chain radical reaction. Initially, Mg donates and electron to bromide and heterolytically breaks the C-Br bond; therefore, this results in a carbon radical, Br - ion, and a Mg+ radical. Next, the carbon radical and the Mg+ radical bond together, and the Mg and Br - ionically bond together2. In the experiment, no initial color change to cloudy gray was observed. Eventually, it was decided to try and
The solid product was then collected from the funnel and added to a hot 95% ethanol solution in an Erlenmeyer flask and completely dissolved. Once the solid was dissolved completely, the solution was allowed to cool to room temperature. Once yellow crystals formed, the solution was placed into
The purpose of this experiment was to synthesize the Grignard reagent, phenyl magnesium bromide, and then use the manufactured Grignard reagent to synthesize the alcohol, triphenylmethanol, by reacting with benzophenone and protonation by H3O+. The triphenylmethanol was purified by recrystallization. The melting point, Infrared Spectroscopy, 13C NMR, and 1H NMR were used to characterize and confirm the recrystallized substance was triphenylmethanol.
8. Repeat step 7 with H2SO4, except that you should use a 10 mL graduated cylinder of H2SO4 and adding 15 mL water.
For this lab, certain actions were performed to facilitate the optimal conditions for the Grignard reaction to proceed. As mentioned above, forming the Grignard reagent and the Grignard reaction must take place in dry, anhydrous conditions. This was why the glassware was initially placed in the oven to evaporate any moisture that was present on the glassware. Additionally, the magnesium used in the experiment needed to be dry too, so it was also placed in the oven to be heated. Creating a dry environment was also why the reaction vessel was covered in the septum because it helped prevent the moisture in the air from entering the reaction. Having water in the reaction vessel would destroy the Grignard reagent and hinder the Grignard reaction. Because the reaction needed to be done in dry and anhydrous conditions, diethyl ether was used as the solvent because it was aprotic meaning that the formation of phenylmagnesium bromide and the Grignard reaction would not be hindered by the protonation of water and alcohols3.
The wet, crude product was placed into the 50 mL Erlenmeyer flask. Small amounts of CaCl2 were added to dry the solution. The flask was sealed and the mixture was swirled and left to settle. Once
In this experiment, 0.31 g (2.87 mmol) of 2-methylphenol was suspended in a 10 mL Erlenmeyer flask along with 1 mL of water and a stir bar. The flask was clamped onto a hotplate/stirrer and turned on so that the stir bar would turn freely. Based on the amount of 2-methylphenol, 0.957 mL (0.00287 mmol) NaOH was calculated and collected in a syringe. The NaOH was then added to the 2-methylphenol solution and allowed to mix completely. In another 10 mL Erlenmeyer flask, 0.34 g (2.92 mmol) of sodium chloroacetate was calculated based on the amount of 2-methylphenol and placed into the flask along with 1 mL of water. The sodium chloroacetate solution was mixed until dissolved. The sodium chloroacetate solution was poured into the 2-methylphenol and NaOH solution after it was fully dissolved using a microscale funnel.
alcohol (2-methyl-2-butanol, MW _ 88.2, d _ 0.805 g/mL) and 25 mL of concentrated hydrochloric acid (d _ 1.18 g/mL). Do not stopper the funnel. Gently swirl the mixture in the separatory funnel for about 1 minute. After this period of swirling, stopper the separatory funnel and carefully invert it. Without shaking the separatory funnel, immediately open
40 g of ice and approximately 30 ml of sulfuric acid is cautiously added to a 100 mL beaker respectively. Weigh 7.6 g of ammonium chloride and 14.0 g of ammonium bromide and place it in another beaker, crushing the lumps until a powdery mixture remains. The powdery mixture is then transferred to a 125 mL Erlenmeyer flask. Add the ammonium salts into the sulfuric acid mixture. Heat is applied to dissolve the salt. Once the
Experiment 4A: Determination of a Partition Coefficient for Benzoic Acid in Methylene Chloride and Water, and Experiment 4B: Solvent Extraction I: Acid-Base Extraction Using the System Benzoic Acid, Methylene Chloride, and Sodium Bicarbonate Solution
b. Place crushed ice in the beaker so the water level is just below the top of the
In the following reaction, benzil was rearranged to from benzilic acid by reacting it with potassium hydroxide in ethanol. 0.100 benzil was utilized and the theoretical yield of benzilic acid was 0.109 grams (see Eq 5). The final yield and weight of benzilic acid was 0.60 grams. The final yield and theoretical yield were used to calculate the percent yield, 55% (similar to Eq 3). The melting point of benzilic acid was 148.3C and the literature value for
The 1,000ml graduated cylinder was held secure in the tub as the gas started to push the water down. Occasionally, the Erlenmeyer flask would be stirred to ensure that the reactants combined. After the reaction was completed, changes to the amount of water in the 1,000ml graduated cylinder was
Because magnesium is a very electropositive metal, it is reactive and inserts itself in between the carbon on the aniline ring and the bromine atom. A cloudy brown-grayish solution formed and bubbles emerged and these processes were indicators that the Grignard reagent was proceeding. The bubbles formed was from the hydrogen gas that arised from the unreacted magnesium specks. It was formed from the quenching step, where HCL was added to the reaction flask and two chlorine ions reacted with the unreacted Magnesium ions to form MgCl2 and h2. This formation of H2 was the hydrogen gas that was produced and appeared in the form of
Heat the precipitate on a hot plate in a beaker to evaporate any excess water.