Aspirin Lab Report

Aspirin Lab Report AbstractThe objective of this experiment is to enable us to conduct the sythesis of aspirin and help us reinforce the skills of recrystallisation and the technique of melting point determination. The main procedures are preparation of salicylic acid, recrystallisation of aspirin, and determining the melting point of aspirin. TheoryAspirin (acetylsalicylic acid) is a pain-relieving compound familiar to everyone. It is used to relieve minor aches and pain and other medical uses such as anit-inflammatory medication. Aspirin is an ester that has high molecular weight and it not soluble in water hence the solid can be separated by crystallization process. Synthesis of Aspirin is known as esterification. All of our chemicals to asprin will be located in the fumehood. The fumehood is a local ventilation device that is designed to limit exposure to hazordous fumes. In the results, we calculated the percent yield and the melting tempurature. Precent yield is calculated by ( Mass of dried asprin)/( Expected mass of asprin). The percent yield is the percent ratio of actual yield to the theoretical yield. The importance for this is to find how much we loss of the sample during recovery. The higher the percent yield, the better your results will be. In our experiment, our theoretical yield we got was 1.83 grams and the precent yield we got 77% yield which shows that we got it to be almost pure. Our melting point of asprin should be in the range of 138-140 degrees celcius. Our salicyclic acid should be in the range of 158- 161 degrees celcius. When we mix our salicylic acid, our asprin, and our commercial asprin with the Fecl3 we should be getÝng different shades of purple. The salicylic acid should be a dark purple, the asprin should be a normal purple, and the commercial asprin should be a light purple. Chemical Data- Reactant Formula Name Concentration Moles Oil of Wintergreen C8H8O3 Oil of Wintergreen 6.75M .027M NaOH NaOH Sodium Hydroxide 6.0M .24M H2SO4 H2SO4 Sulfuric Acid 8.0M .40M Name Mixed with Observations Salicylic Acid Fecl3 Dark Purple Our Asprin Fecl3 Purplish Commercial Asprin Name Fecl3 Start Temperature Light Purple End Temperature Acetyl Salicylic Acid 125 degrees celsius 135 degrees celsius Salicylic 146 degrees celsius 158 degrees celcius ProcedureAsprin I  Transfer 4 ml of oil of wintergreen, which will eventually be added with 40 ml of 6M NaOH ( You will observe precipate)  Make sure while heating to rinse the sides to leave no precipate behind.  Adding 50ml of 8M H2SO4 (You will observe precipate)  Make sure to give ample time to cool for the crystals to form (The more time the better) Asprin II  Make sure properly weigh your salicyclic acid (Important for precent yield)  Add 3.0ml of acetic anhydride and 5 drops of concentrated H3PO4  For step four it is important to pay attention to the thermometer  For step six making sure the it is cool to the touch and don’t rush ObservationsWhen I observed the asprin crystals, they were tightly packed and it seemed like they were all compressed without any air gaps. Then when we melted them and it came into the range of 138-140 degrees celsius. Since the theoretical melting tempurature is 140 degrees celsius, my partner and I determined that the asprin we obtained is pure and didn’t have many impurities. From the calculations, I can evaluate that the asprin is pure. Due to some technique errors and may be leaving some behind in certain steps or incomplete reactions our percent yield was not up to expectation. During the end of our experiment we mixed our salicylic acid, our asprin, and commercial asprin with FeCl3. We noticed that the Salicyclic acid was dark purple, our aprin was a normal purple, and our commercial asprin was a light purple. By these observations we could determine that our asprin did have some of salicyclic acid still in our asprin. CalculationsBeaker- 108.94 C w/ beaker- 113.12 Concentration= 4.18g Moles of oil of wintergreen is post lab question 1 Our Salicylic Acid was- 3.0g Theoretical yield1.4g/138.12g= .0101M .0101=weight of aspirin x 180.1574= 1.83g Percent YieldOur measured aspirin/ theoretical yield x 100= .765 or 76.5% ResultsIn the results, we calculated the percent yield and the melting tempurature. Precent yield is calculated by ( Mass of dried asprin)/( Expected mass of asprin). The percent yield is the percent ratio of actual yield to the theoretical yield. The importance for this is to find how much we loss of the sample during recovery. The higher the percent yield, the better your results will be. In our experiment, our theoretical yield we got was 1.83 grams and the precent yield we got 76.5% yield which shows that we got it to be almost pure. This shows that my partner and I didn’t leave many impurities and was pretty acurate with our results. Our melting point of acetyl salicylic acid started at 125 degrees celsius and ended at 135 degrees celsius. Our salicylic acid started at 146 degrees celsius and ended at 158 degrees celsius. Acording to our theory our results were extremely accurate. When we mix our salicylic acid, our asprin, and our commercial asprin with the Fecl3 we should be getÝng different shades of purple. The salicylic did have a dark purple, the asprin was a normal purple, and the commercial asprin was a light purple. The reason for this is because FeCl3 reacts with phenol groups. Therefore, if you have an aspirin sample and want to test for some unreacted salicylic acid within it, you would add FeCl3, if the solution turns purple, that means you have unreacted salicylic acid. This shows that our asprin wasn’t exactly pure asprin. Disscusions- Overall, I believe the results we have found were extremely accurate to our theory. Our precent yield ended up being 76.5%, which is good, but it leads me to think what I could have done better in this experiment. Obviously we weren’t perfect in our experiment and to my knowledge I belive we left some of the salicylic acid behind during our experiment. Maybe when we had to transfer the 4 ml of oil of wintergreen or add 40 ml of 6M of NaOH we didn’t add the certain amount we needed. When we were heating and using the stirring rod we could have left some precipitate on the rod when we took it out. There could have been numerous things we did durring the experiment that we did to lower our precent yield. Personally, I belive where we went wrong was when we had to filtrate in our experiment I belive we left some in our filtration paper and we couldn’t gdt it all out. This is why I belive we got the percent yield we got, but ultimately I belive my partner and I did a good job. Post Lab QuestionsAspirin I 1) 4.18 x 1/152.15= .027M 2) Not a question 3) Overall the reaction is the conversion of oil of wintergreen to the salicylic acid. C8H803+2OH+2H30+ +(CH3CO)2O 3H20+ CH3COOH+ Aspirin 4) 180.157/138.121 x 4.18= 5.45g 5) You would use hot water, because if it was room temperature it would dissolve. 6) If the water we use in each step isn’t chilled we wouldn’t form crystals. Aspirin II 1) Weight of aspirin/ 1.83 x 100= .765 or 76.5% 2) 76.5% 3) Leaving some precipate in the filtration paper, not rinsing the precipate, leaving some on the stirring rod. 4) -OH 5) Ester 6) Acetyl Salicylic Acid- (138-125)/135 x 100= 96.2% Salicylic Acid- (158-158)158= 100% 7) Due to the results I have gotten the purity of both came out to be very pure.