Benzoic Acid Paper

Percent Recovery of Components Compound Aspirin Caffeine Salicylamide Actual Mass (g) 0.671 0.052 0.283 Expected Mass (g) 1.300 0.0666 0.390 Percent Yeild (%) 52% 78% 73%

The melting point of the final product, diphenylacetylene, was found to be 65-68 degrees Celsius which is right around the ideal 61 degrees Celsius melting point; this shows that purification during the lab worked and that the sample was almost 100% pure. Since only 0.01g of diphenylacetylene was collected and the theoretical yield was calculated to be 0.049g, this experiment had a 20.41% yield. A few sources of error that explain the low percentage could be the loss of crystals when transferred from the test tube to the suction apparatus or when they were transferred from the suction apparatus to the filter paper to be dried and then weighed. Crystals could have also been lost if more than 5 drops of methanol was added because excess methanol would dissolve the crystals. The experiment was successful when looking at the crystals collected from the addition step and the elimination step; however, to improve the percent yield and collected product the the test tubes could have been allowed to cool down in the ice bath past the 5 minutes to ensure all the crystals formed

b. As I mentioned above that I spilled some of the benzoic acid therefore the initial mass

Discussion: As seen in the melting point determination, the average melting point range of the product was 172.2-185.3ºC. The melting points of the possible products are listed as 101ºC for o-methoxybenzoic acid, 110ºC for m- methoxybenzoic acid, and 185ºC for p- methoxybenzoic acid. As the melting point of the sample

The text suggested that the solvent be removed by evaporation via a hot water bath or filtration (Weldegrima 2016). A situation occurred during the lab where time had become a constraint and the hot water bath was being occupied by the naphthalene. The instructor advised that the sand bath be used to isolate the crystals from the solvent, or the crystals and liquid be poured on filter paper and hand dried. The sand bath was too hot and started to melt the solid. This led to the pouring of the liquid and crystals onto filter paper. This method left more room for error, as drying the crystals would be more tedious and it would be more difficult to remove all the crystals from the test tubes. The optimal percent recovery is a 100% for each solid. However, it is expected that less would be obtained. The percent recovery for the benzoic acid in both procedures and the phthalic acid were between 40%-25% less than the desired 100%. The low percent recovery can be attributed to the method previously mentioned, to separate the solvent from the crystals. When pouring the crystals and liquid onto the filter paper for the benzoic and phthalic acid, it could clearly be seen that there were many crystals still stuck to the inside of the tube. A spatula was used to recover as much of the crystals as possible, but not all of the crystals could be collected. This left many crystals still in the test tube which would have skewed the results for percent recovery, as they could not be weighed as well. The naphthalene was different, as it was not pure to begin with. A 1g solid mixture including an unknown amount of naphthalene was used. The lack of information on how much naphthalene was started with, makes it very cumbersome to determine the percent yield. However, .532g of naphthalene was recovered in total. There

Melting points are indicative of identifying an unknown product and the level of impurity the product contains. In this case, the possible identity of the product based on its melting points are determined by comparing the obtained melting points of the product to the melting points of the five possible products. Two mini capillaries, containing the product only, were used to determine the product’s melting point. For one mini capillary, the temperature range was 132.1-134.2℃, and the product’s melting point for the second minicapillary ranged from 135.1-137.5℃. In addition, melting points were obtained with the product mixed with meso-hydrobenzoin. The temperature range was 135.0-136.0℃ and 135.0-137.5℃. Although the recorded melting point values fall into the racemic range, but the results still indicate that the product is a meso-hydrobenzoin. The melting point values for the product mixed with the meso-hydrobenzoin standard explains that it is unlikely that the product is racemic. The melting point values were two degrees from each other due to the meso-hydrobenzoin standard making

The percentage of the product being recovered is more than 50% which is 59%. The Percentage yield obtained is not 100% as what we expected, this might be due to the spillage of the benzoic acids when it was being measured or transferred and the benzoic acid was not weighed properly. It might also be caused by the errors when the benzoic acids solution was not filtered properly and they might have trapped in the filter paper.

In this lab, liquid-liquid extraction was performed to isolate a mixture of benzocaine and benzoic acid. 2.0107 grams of the mixture was first weighed out for the trials. When HCl was added to the mixture for the first acid extraction of benzocaine, an emulsion formed during inversion and venting that prevented a defined separation of the two layers. 8 mL of water was therefore added before continuing the extraction. The addition of NaOH then turned the top aqueous layer basic, indicated by the pH strips that turned blue when tested. A vacuum filtration isolated 0.29 grams of benzocaine and a MelTemp apparatus measured the crystal’s melting point ranges to be 85.1C-87.4C. For the base extraction of benzoic acid, the aqueous layers were retrieved

Sample number Initial mass (g) Final mass (g) Materials Remaining (%) Rhyolite 1 35.20 35.30 100.28 Rhyolite 2 28.00 27.80 99.28 Rhyolite 3 19.20 19.30 100.52 Rhyolite 4 24.20 24.20 100.00 Rhyolite 5 15.90 14.90 93.71 Rhyolite 6 25.90 25.90 100.00 Rhyolite 7 22.10 21.70 98.19 Rhyolite 8 18.20 18.10 99.45 Rhyolite 9 29.90 29.90 100.00 Rhyolite 10 25.20 25.20 100.00 Average Percentage of Materials Remaining: 99.14%

In part A, I had to determine the distribution coefficient of benzoic acid between MTBE and H2O. I started with 0.0511g of benzoic acid and mixed with water and MTBE to a centrifuge tube. MTBE was the top layer which H2O was bottom layer as water has a higher density. There was usually a separation line formed between two layers, which can help us to remove the bottom layer. The easiest way to identify the two layers was to put into the centrifuge machine to let the layers separate.

The percent recovered was determined to be 91.67%. Acknowledgements: I would like to acknowledge my lab partner Melissa Colwell for assistance during the lab. References: 1) Organic Chemistry Laboratory Manual, Spring 2015 Edition, Department of Chemistry, Binghamton University, Binghamton New York, 2012 pp 3-4, 77-86. 2) "Liquids."

Benzo[a]pyrene (B[a]P), a polycyclic aromatic hydrocarbon (PAH) is formed during the incomplete combustion of organic material (eg. gasoline and wood) and also found widely in tobacco smoke and grilled foods. Anthropogenic and industrial activities result in an elevated concentration of B[a]P in the environment.1 B[a]P is a known human carcinogen and also causes teratogenicity, neurotoxicity and immunotoxicity.2

Objective: The objective of this experiment is to use acid-base extraction techniques to separate a mixture of organic compounds based on acidity and/or basicity. After the three compounds are separated we will recover them into their salt forms and then purify them by recrystallization and identify them by their melting points.

A. There a many different test that are chemical and physical that we could use for our soil sample. One physical test that can be performed is a particle size distribution of a soil sample. For this test, you get your sample of soil and place it in a jar. You then add water, a drop of soap, and shake the jar. After a length of time the contents of soil will develop into layers. You would then see the makeup of your soil with sand being at the bottom, silt in the middle, and clay at the top. You can then find the distribution of the soil and determine the soil texture. This soil test could help a cooperative extension service to determine if they need to add more contents like sand, silt, or clay so it will increase the growth of plants on that particular area where the soil is growing. A chemical test that can be preformed is a PH test to get the acidity of the soil. You test this by placing PH paper in soil concentration and the color change will indicate the PH of the soil. The a high PH shows the level of the base while the low PH will show how acidic the soil is. This is important to a recommendation because the PH can affect nutrients, minerals and growth.

Acid Rain is classified as rain with a pH lower than 5.7. The pH of normal rainfall is around 5.6; the acidity in this is natural and due to the CO2 and carbonic acid that is present in the atmosphere. Acid rain contains higher amounts of nitric and sulfuric acids compared to normal rainfall.