Fractional Distillation

The substitution reaction was successful but not fully effective. 19. If the data was inconclusive, then comparing various compounds and the unknown based on physical characteristics would be the first step, titrations would also be a good method. 20. To get a better yield, redoing the experiment would require careful attention in the recrystallization steps: amount of solvent used, how hot solvent is, if the mixture cools to room temperature before placing it in an ice

Solvent used in the elution process would be the mobile phase and solvents of different polarity would have a significant impact on the separation due to the varying solubility of compounds in different solvents. Hexane, being the less polar solvent, interacts mainly with the less polar analytes but very slowly with polar analytes. Therefore using hexane at the start of the elution process allows the less polar compound to be eluted out first. After the complete collection of less polar analyte, the mobile phase was changed to the more polar hexane/ethyl acetate solvent, which has stronger interaction with the more polar component, allowing it to be eluted out faster. The change in solvents throughout the elution process would allow for an effective and efficient separation of the compounds β-carotene and chlorophyll in the crude extract of green leaves.

Fractional distillation was performed in this lab to separate a mixture of two miscible liquids with a difference in boiling points of less than 40 C, and to predict their identities. After that, gas chromatography was used to confirm the identities of the two liquids in the unknown solution, and to obtain the ratio of the composition of the solution with respect to these two liquids. Distillation is a separation technique that relies on two substances having different boiling points, so that one evaporates and condenses in a separate flask. Simple distillation can be used for mixtures of solids and liquids, as liquids typically have lower boiling points than solids, or for mixtures of two liquids with a difference in boiling points greater

Abstract The experiment was performed in order to compare the effectiveness of Simple and Fractional distillation in separation of solid impurities from liquid and liquids with difference in boiling point higher than 25⁰C. The distillation curves of both processes were graphed on each case and compared. The main source of possible error was discussed and the way to improve the experimental procedure was proposed. It was concluded that the Fractional distillation is more efficient procedure than Simple distillation in liquid separation. However, in case of separation of solid impurities from liquid or liquids with high difference in boiling points Simple distillation can be preferred.

Thus, a higher percent yield was calculated for acetaminophen. Although, a second filtration was performed; however, a very low concentration of acetaminophen was recovered as a result of human errors, and the transfer of solution/solid contributed to product loss. However, the mass use to calculate percent yield was the first mass recorded because it may be more consistent than the mass measured after the second filtration. However, for further experiments, the percent yield must be calculated with the corresponding mass of product (actual yield) even though there is loss of product, the actual yield is the final concentration of the recovered product in the experiment. Thus, the results may be more conclusive if the actual percent yield was used.

This means that the reaction acted quicker and would increase the probability of the sample being pure, this would mean that you didn’t have to wait very long and the material changes that have taken place whilst the reaction was taken place would be easier to define and make a note of the start and end point. The precipitation reaction forms aspirin crystals which involves joining ions in solutions to form a precipitate. Another technique that we used was filtration. The equipment we used was a Buckner which uses gravity and a vacuum and this gets rid of the moisture in the sample and creates a dry sample. Another technique would be dissolving and reacting which involves the crystals to be made and for the chemicals to react to make the

React ethanoic acid and 1-butanol under reflux with the presence of trace amount of concentrated sulfuric acid. In this step, the amount of 1-butanol and ethanoic acid used is the same so that a maximum 70% ester yield can be synthesised at the end of the experiment. After the reactants is accommodated in the reactant flask, the trace amount of concentrated sulfuric acid is added drops-by-drops into the reactant flask and the flask is swirled while adding the acid. Additional of concentrated sulfuric acid is to use as a catalyst to increase the rate of reaction by donating a proton to the oxygen atom in carboxylic acid to allow for the mechanism for esterification and thus, the satisfactory yield of ester can be achieved. Moreover, it acts as dehydrating agent, forcing the equilibrium to the products and lead to a greater yield of ester.

This reaction was able to happen during designated lab time due to the fact that a phenol was used. Phenols or more reactive than unsubstitued benzene rings due to the presence of the alcohol on the benzene ring. The alcohol is considered an activating group due to the oxygen’s ability to donate its lone pairs into the benzene ring thus giving it more electrons and thus making it more nucleophilic and more likely to react with the introduced electrophilic species. As aforementioned, there are various products formed in this reaction the two major products formed though are the ortho and para products. It is debatable which product is more prominent due to steric reasons and the capability of each product to conduct in hydrogen bonding.

In a supersaturated solution, the solvent is unable to dissolve into the solution, possible because of temperature or due to the fact that there is too much of the solute. Supersaturated is when the concentration of a solution increases beyond the saturation point. Unsaturated solutions have solute concentrations that are lower than the equilibrium soulbility. For a solution to be unsaturated, it has to contain less solute than its maximum amount. When it comes to making soda, a saturated solution would be needed.

When the aqueous layer was added to the vial, calcium chloride was then added to dry the solution. If the solution was dry enough, a large peak between 3300-3500 would have been present in the IR spectrum. In order to obtain the IR spectrum two Classification test were performed. The Bromine test and Permanganate test were used to determine if alkenes were indeed present in the solution. Both test were positive for the compound.

The final topic, also in the experiment, is the importance of the materials. The acid with the lowest ph level will be the highest acid that works better than the other acids. Higher acids have more hydrogen ions. The baking soda base is a high ph and soaks up hydrogen ions. Based on the results of testing the various liquids will help determine which ph level is best to be used.