Sn2 Nucleophilic Substitution Lab Report

An Erlenmeyer flask was used to accommodate the largest volume of recrystallization solvent calculated and was cooled in an ice bath to increase the yield of crystals. The solid was collected by vacuum filtration and washed with a small amount of ice water. The product is then dried to a constant mass by use of an oven and weighed. A small amount of the unknown was compared to two samples of acetanilide and phenacetin for a melting point range to determine the identity. The temperature of the unknown was recorded when the first trace of liquid can be seen and when the unknown was completely liquid.

The possible reasons for this discrepancy were discussed as the plausible mistakes committed in the procedure, such as allowing the solution to excessively cool, as well as the possibility of having used faulty or contaminated reagents and components. In general, in order to improve the results of future experiments, as well as to have potentially improved these results, a more diligent and strict manner of performing these experiments is necessary, as well as ensuring the purity and condition of any reagents used and to ensure that no objects such as glassware are compromised. Considering this information, the experiment must be considered a failure, although the purity of the small yield could be considered pure, the yield’s sheer lack of size is evidence of the fact that the reaction did not reach completion, whether it be because of a low temperature or a lack of purity in components. Therefore, it must be regretfully reported that the objective of the experiment was not

The first TLC plate showed that the fractions collected during the experiment that appeared to be the purest were fractions 4 and 6. These two fractions and fractions number 5 were combined for the final product. The Rf values for the standard carvone, fraction 4, and fraction 6 were all 0.32 indicating that these compounds were

Recrystallization purifies a crude product by separating the product from impurities based on solubility. The product being purified should easily dissolve in the chosen solvent at high temperatures, but not at room temperature. Impurities should dissolve in the solvent at room temperature but not at high temperatures.

The H-NMR of the unknown alcohol was provided for analysis in order to determine the identity. Based on the peaks and their respective locations, the unknown was determined to be isopentanol. The peak at 0 ppm was the TMS. From this, the first doublet peak represented the six hydrogens located on the two terminal carbons, the signal was split as a result of the single hydrogen from the adjacent carbon. This peaks falls within the typical range for a primary alkyl hydrogen, 0.7-1.3 ppm. The next peak is a quartet that has a

The percent yield of this experiment is calculated to be 33.9% thus making this experiment not very reliable and the product, not very pure. This may be due to a number of different reasons. First of all, some transfer residue could have remained on the conical vial after the sample was transferred into the pre-weighed vial. Another possible source of this low percent yield, may have been from adding too much drying agent. If too much of the anhydrous sodium sulfate is added, some of the product will be dried out of the solution. The idea of the drying agent is to take out the excess water in the product, however, if left in the vial for too long or too much was added, the water may have all been absorbed, but now some of the product has as well. One final reason that could contribute to this low percent yield is when, after extracting the bottom layer in the conical vial with the sodium bicarbonate, perhaps too much product was removed along with that bottom layer. By taking out some of the product that would have contributed to the overall percent yield calculation, the yield will automatically be lowered.

As discussed in lecture, the determining factors of a substitution reaction is likely to occur in either S_N 1 or S_N 2 by: substrates, leaving group, strength of the nucleophile, and the type of solvent.

To conclude, it is evident from the Rf values obtained that unknown # 3 Rf is closest to that of 2 – Octanone. With a 7.2 % error, this can be due to the reagent being diluted with too much ethanol or still containing traces of the acid, however if traces of the acid are present then the melting point[3] should be significantly lower.

An impure substance of benzoic acid was used in the attempt to purify and remove impurities through the process of recrystallization. Recrystallization is perfect for purifying solid mixtures by allowing the soluble material the solute in this case impure benzoic acid to create a solution with the solvent of 95% ethanol when heated. If the energy was not added to the solvent then the solute would not dissolve completely for what was desired and the process would not work properly. Recrystallization is the easiest way to isolate and purify solids from and unknown mixture. To perform a recrystallization of a solid mixture a solvent should be acquired and heated to allow the mixture to dissolve into solution. Approximately 2.0 grams of crude

In order to achieve the best result, this experiment was broken into two part: the first part of this experiment involves carrying out solubility tests on known compounds, N-pivaloyl-o-toluidine, and in the second part the TLC and solubility tests was used to find a suitable recrystallization solvent for an unknown compound. For Experiment 6A, a 50 mL round-bottom flask with a small stir bar and septum was flame-dried under the hood, and cooled down to room temperature. Then, a balloon was filled with N2 and attached to the rubber septum in the round-bottom flask via a 20G, ½ needle. The flask was clamped to a stir plate and 9.3 mL of DCM was cautiously added using a 12 mL syringe and a long thick needle. Furthermore, 1.2 mL of pivaloyl chloride was added to the mixture using a 3 mL syringe and a 22G‚1/2 needle. Next, the flask was carefully submerged into an ice and water bath for 15 minutes until the

I - Introduction - In chemistry, the use of a scientific method to solving problems and collecting data is crucial to a successful conclusion. Observation, Investigation and Interpretation are the scientific tools that are used to help construct this conclusion. Observation is used to gather both quantitative and qualitative properties of matter in order to set a basis upon which every other part of the experiment is built. Then, the observations are investigated and records are kept of the results. Interpretation is the final step of the process.

Recrystallization is a technique to purify organic compounds. Both the impurities and the compound are dissolved. The impurities are forced out, and the purified compound is recrystallized. The purpose of this lab is to use the recrystallization method to purify an impure naphthalene compound using methanol.

In order to properly identify an unknown compound and its state of purity, it is important to take note of the compounds physical properties. The physical property that this lab focuses on is the melting point. The melting point is found through the use of a DigiMelt, which is a melting apparatus. When studying the melting point of a compound, it is important to note that the more pure a substance is, the higher the melting point and the narrower its melting point range. The purpose of this experiment is to identify known and unknown substances based off of their melting points.

To examine this, the theoretical yield was determined and recorded as 0.6127 grams. Then the actual product was massed to determine the actual yield and documented as .1041 grams. This results in a percent yield of 16.99%. While this is a very yield and appears to highlight the inefficiency of the reaction there are likely several errors that contribute to these appearant inefficiencies. First, several TLC samples were removed from the reaction while it was in progress and an additional sample was removed to confirm the completion of the reaction. Next, more product was removed in order to obtain an IR and H1NMR spectrum and confirm the identity of the product. Additionally, the liquid-liquid separation technique is not a highly efficient method of extraction and thus likely resulted in the loss of some product. Furthermore, the product was transferred between reaction vessels several times in order to remove residual water and undergo rotary vaporization and in each of these transfers it is likely that a small amount of product was

The character of numerous organic compounds is resolved through a blend of different tests, methods, and procedures. When attempting to discover the identity of a specific compound, different strategies and lab techniques will be used, for example,crystallization, recrystallization, and so on.,