TFCH2002 Organic Chemistry II Lab Report Experiment title: A Floral Fragrance, Methyl Benzoate Name: Conor Fitzpatrick Student number: C14740151 Course code: DT422/2 Report submission date: 02/03/16 Aims • To convert benzoic acid and produce methyl benzoate by Fischer esterification. • Learn reaction mechanism involved in esterification. Benzoic acid + methanol Methyl benzoate + water Introduction The ester functional group can be synthesized a number of different ways. These esters have very pleasant aromas and contribute greatly to the flavour and smells of many fruits. Due to this, the food industry often uses single esters to obtain synthetic flavouring agents and odours. The synthesis in this experiment …show more content…
Shake funnel and rinse off water layer ( This contains the sulfuric acid and majority of methanol). Again wash the ether with 25ml of water and then wash the organic layer with 25ml of 10% sodium bicarbonate to extract unreacted benzoic acid. Again shake separatory funnel with frequent venting of pressure and opening the stopcock. Allow the separation of layers and drain off bicarbonate layer into a beaker. Wash ether layer with saturated sodium chloride solution and retain ether layer. In a small 125ml Erlenmeyer flask, dry the ether solution over anhydrous calcium chloride. Add sufficient calcium chloride so that it no longer clumps to pellets added earlier on the bottom of the flask. Remove the solvent using a rotary evaporator and weigh product. Results 1 mole of benzoic acid (C6H5COOH = 122.12grams) reacts with 1 mole of methanol (CH3OH = 32grams/mole) to produce 1 mole of methyl benzoate (C6H5COOCH3 = 136.15grams) and 1 mole of water. 5.0grams of benzoic acid Molar mass of benzoic acid: 122.12g/ml 5.0g122.12g=0.041moles 19.75grams of …show more content…
The percentage recovery of methyl benzoate was 28.93% which is a very low result. This was not as expected. This could be due to a number of different factors, mainly human error. The glassware used may have been too large for the quantities handled. The mixture may have not been refluxed fully. Initially not all of the 5.0grams of benzoic acid went into the round-bottomed flask as there was still residue left on weighing boat. This would mean the starting amount of benzoic acid was less then stated. There was some product loss during the draining of the aqueous layers. All these will account for the low yield that was produced. However, the ester formed produced a wintergreen odour and this was to be suspected. Conclusion Due to the very low percentage yield, the results were not what was wanted. The ideal product range would have been between 80 – 100% which was far from the recovered product. When you mix a carboxylic acid with a alcohol in the presence of a catalyst an ester is formed that gives off a pleasant fragrance. In the reaction a wintergreen smell was composed and this is a positive result from the experiment proving the mechanism of
After 28 minutes, the mixture stopped boiling, and approximately 4.5 ml of bromobenzene was added drop by drop in the mixture, and color of the mixture was turned light brown orange. Then, the phenylmagnesium bromide was cooled in ice bath for a few minutes, and 10 ml of anhydrous diethyl ether was added in the mixture by using the syringe. After that, approximately 2.3 ml of methyl benzoate was added to the reaction, and it was added slowly slowly because the reaction was exothermic which needed to be cool in order to maintain a gentle reflux. Once all the methyl benzoate solution was added, the heating mantle was removed from the reaction flask and was cooled to the room temperature. During the reaction, a milky white salt began to precipitate, and the reaction flask was swirled for ten minutes until most of the reaction became visibly subdivided.
To test for the presence of the ammonia cation, a scoop of the unknown compound was mixed with NaOH to see if the resulting solution had a noticeable smell that would affirm the presence of ammonia. A moist piece of pH paper was then held near the solution to see if the ammonium would dissolve the water on the pH paper. The next cation test performed was the flame test. A gram of the unknown compound was held by a metal stick above the flame of a Bunsen burner to see what color flame the compound would produce. The chart in the lab manual on page 63 was used to determine what cation correlated with what flame color.
The reaction to synthesize benzocaine was known as a Fisher esterification reaction. The Fisher esterification was reaction between alcohol and carboxylic acid in the presence of acid. The reaction was used to form an ester. In the experiment, sulfuric acid acted as a catalyst and necessary for this reaction to occur. There was a change between the –OH group of carboxylic acid to an –OCH2CH3 group in the reaction.
As seen in table 1, the theoretical yield was .712 g of C_17 H_19 NO_3. The % yield of this experiment was 7.51 % of C_17 H_19 NO_3. . This low yield can be explained from a poor recrystallization technique combined with potential contamination. Throughout the experiment, the mixture changed color from green, orange, to yellowish lime, and eventually clear.
3. Upon adding 20 drops of NaOH, a white precipitate was formed signifying acidic impurity. In the second NaOH mixture, about 20 drops were administered and no precipitate formed indicating that the ample is more pure than before. Data: Weight of flask = 75.10 grams Weight of the flask with solids =
The yellow solution containing the reactants was slowly poured into the beaker containing the cold water and the acid in order to cause the precipitation of the alcohol, 9-fluorenol and to destroy (hydrolyzed) the unreacted excess sodium borohydride. Subsequently, the white precipitate was vacuum filtered and washed twice with 20.0 ml portions of distilled cold water by pouring the liquid into the Buchner Funnel during filtration. It was necessary to wash the alcohol prior to recrystallization considering that the C-OH bond is easily broken by the formation of a stable and benzylic carbocation that favors the synthesis of difluorenyl ether. Finally, before the purification by recrystallization of the obtained product, the white solid alcohol was allowed to dry over a period of a
(150.22g/mol)(3.5 x 10^-3 mol of nucleophile) = 0.525 g Actual yield = 0.441 g, Percent Yield = (0.441g/0.525g) x 100% = 84% 10. Percent recovery from recrystallization = (0.172g/0.441g) x 100% = 38% 11.
The percent yield was 22.33%. In most cases, that means that a lot of possible product was lost. However, in this case, that was not true. When Benzaldehyde reacted with the Wittig reagent, it produced two products: E-Stilbene and Z-Stilbene. The Z product was a liquid, while the E product was a solid.
Verna Wang Hannah Palmer CHEM 101-069 Lab 11-19-16 Stoichiometry and Limiting Reagents Lab Report Purpose: We are using the reaction of sodium hydroxide and calcium chloride to illustrate stoichiometry by demonstrating proportions needed to cause a reaction to take place. Background: Just like a recipe would call for a specific amount of one ingredient to a specific amount of another, stoichiometry is the same exact method for calculating moles in a chemical reaction. Sometimes, we may not have enough of or too much of one ingredient , which would be defined as limiting and excess reagent, respectively.
The percent yield was calculated to be 88.1%. Some amount of the product was lost when transferring the product from the Buchner funnel to the balance to measure its mass. To ensure the formation of the desired product, melting point of the product was measured to be 119.8-121.90c, which is in the range of the normal melting point of 2,4,6-tribromoanilne, 120-1220c. Thus, the product was indeed
In other lab procedures, benzoic acid is sometimes substituted for anisole in the Friedel-Craft acylation. However, the reason benzoic acid
The melting point range for the crude product was 113-115.3℃. the melting point range for the purified product was also 113-116℃. This melting point range was almost perfect to that of the theoretical melting point which is 113-115℃ proving that the product was in fact created. When looking at the percent yield of the crude acetanilide, there was an 81% yield which was a very good yield because the average percent yield is between 80-90%. The percent recovery of the acetanilide was 88% which is also very good because much of the product was recovered meaning that the product was in fact
Data suggests that Water is the best solvent that will allow for better saturation and the best recrystallization of benzoic acid, this is largely due to water being a polar molecule whose properties allow for carboxylic acid groups, such as the one found in benzoic acid, to disassociate and donate protons to the water
Methylene chloride and water are both polar, as is benzoic acid, however, both benzoic acid and methylene chloride are only slightly polar. They are very similar in chemical properties because they are just slightly polar. Why benzoic acid is high in mass is explained by the similarity in chemical properties, and the reason the partition coefficient is greater than 1. Mine resulted in a partition coefficient of
Abstract The unknown concentration of benzoic acid used when titrated with standardized 0.1031M NaOH and the solubility was calculated at two different temperatures (20◦C and 30◦C). With the aid of the Van’t Hoff equation, the enthalpy of solution of benzoic acid at those temperatures was determined as 10.82 KJ. This compares well with the value of 10.27KJ found in the literature.