Formal Lab Experiment - Essay Example

FORMAL LAB REPORT Lab Section Experiment Number affiliation OBJECTIVE The aim of the experiment wasto allow the aldehyde:acetone to react with the excess of acetone to come up with a dianisalacetone a bis-aldol product. This is important because the products of the condensation are directly applicable to daily life. 2. EXPERIMENTAL From the experiment acetone was taken to be the reagent, therefore, the group members were very keen to use equipment with acetone traces this is because they could easily influence the outcome of the experiment. During the experiment, 6 mL of aqueous NaOH solution was added to 50mL flask then later on 10 mL of acetone was added. The flask was then place on the magnetic stirrers of the bench and then stirred. 0.5mL of p-anisalaldehyde was then dissolved in 2mL of ethanol into the beaker and then swirled to mix the reactants well. The p-anisalaldehyde solution was then added drop wise with the pipette to the acetone and NaOH solution for a given period of time before the next drop was added to ensure that the solution was mixed well. The reaction was stirred well for 25 minutes. The color change of the solution provided the visible indication of the product formation. At the end of the experiment, the stir bar was returned to the instructor and left the magnetic stirrer on the table. In the Dianisalacetone synthesis, acetone was used as a reagent in the reaction. During the experiment, 3 mL of aqueous NaOH solution was added to 25mL flask then later on 10 mL of acetone was added. The flask was then place on the magnetic stirrers of the bench and then stirred. 1 mL of p-anisalaldehyde was then dissolved in 10 mL of ethanol into the beaker and then swirled to mix the reactants well. The p-anisalaldehyde solution was then added drop wise with the pipette to the acetone and NaOH solution for a given period of time before the next drop was added to ensure that the solution was mixed well. The reaction was stirred well for 20 minutes. At the end of the experiment, the stir bar was returned to the instructor and left the magnetic stirrer on the table. To find the isolation and purification of Anisal or Di-Anisalacetone, the reaction mixture was diluted in the Erlenmeyer flask 10mL of tap water. After submitting to the supervisor, the diluted mixture was then transferred to the separatory funnel found at the HOODS. After draining the yellow organic layer, the solution was later dried with the anhydrous sodium sulfate and then filtered into the round bottom flask. The solvent was later removed with the help of the rotary evaporator and water bath found at room temperature. The results from the above procedures were than tabulated and graphed as shown in the results section. 3. RESULTS a) Table of Reagents Reagent FW (g/mol) B.P Degrees Celsius Density g/ml Required by Procedures Measured/Used by you Grams ml moles Grams ml moles P. Anisalalhyde 136.19 248 1.12 0.56 0.5 0.00411 0.56 0.5 0.00411 Acetone 58.08 56 0.791 7.91 10 ml 0.136 7.91 10 ml 0.136 16% NaOH Catalyst 0 0 0 0 6 0 0 6 0 95% Ethanol Solvent   0 0 0 2 0 0 2 0 b) Table of Products Product Yield Obtained MP Identification of IR bonds Identification of m/Z   G Mole % Anisalacetone 0.33 0.0024 58.97 56-58 C=O stretch, C-H stretch 161 Base Peak Dianisalacctone 0.038 0.0029 67 118-122 C=O stretch, C-H stretch, C-O stretch 294 Base Peak 4. DISCUSSION The base peak at Anisalacetone occurred at m/z 161 as shown in the diagram below. The spectrum formed the C=O stretch and C-H stretch. Additionally, the base peak at Dianisalacetone occurred at m/z 294 as shown in the diagram below. The spectrum above formed a =O stretch, C-H stretch, and C-O stretch Graphically, the mass spectrum of the para-Anisalacetone and the mass spectrum of the para-di-Anisalacetone is shown below respectively. And During the synthesis of the anisalacetone, the limiting agent was 4 methobenzadelhyde while the excess was the acetone in the ration of 1:1. Their concentration is as shown in the calculation below 4-Methoxybenzaldehyde: (0.5 mL) x (1.12 g/mL) = 0.56 g (0.56 g)/(136 g-mol-1) = 4.12 mmol (limiting reagent) Acetone: (10 mL) x (0.791 g/mL) = 7.91 g (7.91 g)/(58 g-mol-1) = 136 mmol (large excess) During the synthesis of dianisalacetone, the limiting agent was acetone as justified in the calculation below 4-Methoxybenzaldehyde: (1 mL) x (1.12 g/mL) = 1.12 g (1.12 g)/(136 g-mol-1) = 8.24 mmol (twofold excess) Acetone: (0.3 mL) x (0.791 g/mL) = 0.237 g (0.237 g)/(58 g-mol-1) = 4.09 mmol (limiting reagent) From the experiment, it was realized that the limiting agents were different. This is because the formation of the dianisalacetone required reaction of the two equivalents for the 4-methoxybenzaldehyde with a single equivalent of the acetone. During the experiment, the group members did not worry of the aldol condensation between the acetone molecules this is because the mesityl oxide and the diacetone are liquid in nature at an ambient surrounding and will be in the position to be removed during the workup of the product. 5. CONCLUSION The experiments proved the aldol condensation whereby there was self-addition that involved two molecule of similar ketone or aldehyde and the based to form a carbon to carbon bond that joins the carbonyl carbon of a single molecule to the alpha position of the second molecule. From the experiment it was proved that the molecule contained a reactive carbonyl group and a reactive hydrogen in the alpha position. The aromatic aldehyde did not have hydrogen atoms in the alpha position but it was in a position to participate in the mixed aldol condensation with another ketone that furnished the alpha hydrogen. The success of the reaction depended on the stoichiometric ratios of the reactant and the rate and order of the addition for the chemical to react in the mixture. During the purification and isolation the anisalacetone was dissolved completely in the reaction mixture while the di-anisalacetone was partially precipitated from the reaction mixture. 6. PROBLEMS Since the sodium hydroxide is corrosive, one of the group members happened to come into skin contact with it and it really caused a damage on his skin. Additionally, the members of the group lacked the safety goggles putting the members at risk from the toxic and irritant smell of p-anisalaldehyde. One of the major problem that was faced is that in various cases, the conditions were not sufficiently mild. This is because the aldol product that was initially formed reacted in the elimination reaction to form the enone which did not favor the main objective of the study. Additionally, from the experiment it was realized that the ketone contained the reactive hydrogens in both the alpha positions. This made the reaction to be complicated by the formation of the bis-aldol product. Read More