Experiment 2 Acid-Base Extraction Lab Report PDF

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Name: Catherine Corniello Partner: Peter Anderson TA: Xiaoliang Wang Experiment 2: Acid-Base Extraction Separation of an Organic Acid, a Base and a Neutral Compound

Introduction The aim of this experiment is to be able to separate an acid (benzoic acid), a base (4chloroaniline), and a neutral (naphthalene) compound, through methods of acid-base extracting (Solomon, 2018). We should be able to characterize each compound by comparing their melting point to the literature value and whether it is sharp, to ensure if it is pure or not. The main technique being used for this experiment is extraction, one of the most useful techniques in Organic Chemistry (Solomon, 2018). An extraction that is more common in the day to day life, is the extraction of tea or coffee through a filter, to be able to steep the concentrated contents of the leaves or coffee ground, using water to facilitate the process. To be able to perform this extraction, a chemical reaction must be performed in a separatory funnel, therefore, resulting in the separation of layers between organic and aqueous (Solomon,2018). It is called an acid-base or a liquid-liquid extraction because this process allows an acid, base, and neutral compound to be able to be separated from a general stock solution of an even amount of each chemical. In this case, it would an amount of 1 gram per compound, a total of 3 grams. With this experiment, knowledge of vacuuming and the condensation and precipitation of a substance will be needed.

+20ml saturate NaOH + cool in ice bath solution (to remove any + 6M HCl Experimental Section 3g Stock Mixture Conical + cool in ice bath residual water in molecules) dropwise + dry + add 3M NaOH dropwise +shake, venting + litmus test, + weigh + test pH with litmus +see two layers acidic + % recovery= + dry +draw off the paper, +bottom 30 ml layer 5% HCl Organic Solution + see (weight/1g) x100% + weigh = basic into aqueous organic waste + Cap then shake vigorouslyblue + 50 mL 5% NaOH precipitation + melting point (sharp, + % recovery= + see precipitation container + Venting + cap, shake, vent + vacuum lit. value) (weight/1g) x100% Lower Level (Aqueous +draw let stand for 10layer minutes off organic solution + anhydrous NaSO4 Lower Level (Aqueous ++draw off lower + letpoint it stand for 1-2 minutes Organic Solution in + draw off lower layer into Upper (ether) + dry + melting (sharp,lit. value) filtration Separation + melting point (sharp lit value) 4 Chloroaniline Benzoic Organic Flask #1 FlaskAcid #2 + vacuum filtration t i Funnel l fl Solution k l S l i ) i l fl k +iDecant i i l fl k l i )

Table of Chemicals Table 1

ment, including th

Structure

Chemica l Formula

Molar Mass

ies.

Meltin g Point

Boiling Point

Hazards and Toxicity

Benzoic Acid

C7H6O2

122.12 g/mol

122°C

249°C

-Corrosive -Irritant -Health Hazard

Naphthalene

C10H8

128.17g/mo l

80°C

218°C

-Irritant -Health Environmenta l Hazard

127.57 g/mol

6871°C

HCl

36.46 g/mol

-114.22 °C

-85.1 °C

-Corrosive -Acute Toxic

NaOH

39.997 g/mol

318 °C

1388 °C

-Corrosive

6

6

Chloroaniline

Hydrochloric Acid (HCl)

232°C -Acute Toxic -Irritant -Health Hazard Environmenta l Hazard

H-Cl

Sodium Hydroxide (NaOH)

Na-O-H

Diethyl Ether

C4H10O

74.12 g/mol

-116.3 °C

34.6 °C

-Flammable -Irritant

Results Table 1.2. Recovered masses, melting point, and percent recovery, of the following chemicals.

Benzoic Acid

0.442g

44%

Melting Point Initial Final 123.1°C 124.5°C

4-Chloroaniline

1.40g

104%

67.3°C

69.5°C

Naphthalene

0.826g

83%

122.3°C

124.2°C

Mass

Percent Recovery

Percent Recovery Calculations: Percent Recovery of Benzoic Acid: Percent Yield = (Actual Yield/ Theoretical Yield) x 100% = (0.442g/ 1g) x 100% = 44% Percent Recovery of 4-Chloroaniline: Percent Yield = (Actual Yield/ Theoretical Yield) x 100% = (1.4g/ 1g) x 100% = 104%

Percent Recovery of Naphthalene: Percent Yield = (Actual Yield/ Theoretical Yield) x 100% = ( 0.826g/ 1g) x 100% = 83%

Discussion According to our results, 4-Chloroaniline had the highest percent recovery of 104 percent. However, this leads to believe that the 4-chloroaniline produced may not have been dried and may have impurities. The initial and final melting point resulted matches up almost perfectly with 4-choroaniline’s melting point value of 68-71°C. This could be due to human error in draining off the lower layer, it could have been contaminated with the upper layer. As for the Benzoic Acid, when filtering out the precipitate, it took a while to dry, as it felt still very moist after a while of vacuuming and being left to dry. This could have contributed to the low percent recovery of 44 percent. The initial and final melting point result was also a few degrees higher than the true melting point of Benzoic acid. Like 4-chloroaniline, this could be due to lack of drying and the remaining of other chemicals, causing it to be impure. Naphthalene has a relatively high recovery percentage, of 86 percent. However, the values of the initial and final melting point resulted were very off from Naphthalene’s melting point of 80 degrees Celsius. The results, 122.3°C and 124.2°C, related more closely to that of Benzoic Acid’s melting point, this shows that Benzoic Acid could have still been combined with Naphthalene resulting in impurities.,

Conclusion We can conclude that none of the three- naphthalene, benzoic acid, or 4-chloroanilinecompounds extracted were pure; all showed signs of impurities. Whether it be a low percent recovery, or skewed melting points, these final compounds resulted to be impure. This could have been derived by any factors, such as, draining the separatory funnel incorrectly (human error), faulty scales (equipment error), not drying the compound enough, and many more. Despite the potential sources of errors, this experiment was performed correctly and correlates with the theoretical background. This technique of extracting can be applied in the real world, especially in the kitchen. When producing vanilla extract or almond extract, etc., the concentrate of the product is extracted into its purest, most rich form, using alcohol. Moreover, this experiment did set out what it aimed to do, separate three compounds, despite the encountered experimental error. We were able to turn a liquid stock solution into the three original solids.

References Solomon, W. 2018. Experiment 2: Acid-Base Extraction: Separation of an Organic Acid, a Base and Neutral Compound, Experimental Organic Chemistry Laboratory Manual, University of South Florida, Tampa, Fl. pp 10-13. National Center for Biotechnology Information. PubChem Database. 4-Chloroaniline, CID=7812, https://pubchem.ncbi.nlm.nih.gov/compound/4-Chloroaniline (accessed on Feb. 7, 2020)

National Center for Biotechnology Information. PubChem Database. Benzoic acid, CID=243, https://pubchem.ncbi.nlm.nih.gov/compound/Benzoic-acid (accessed on Feb. 7, 2020) National Center for Biotechnology Information. PubChem Database. Hydrochloric acid, CID=313, https://pubchem.ncbi.nlm.nih.gov/compound/Hydrochloric-acid (accessed on Feb. 7, 2020) National Center for Biotechnology Information. PubChem Database. Naphthalene, CID=931, https://pubchem.ncbi.nlm.nih.gov/compound/Naphthalene (accessed on Feb. 7, 2020) National Center for Biotechnology Information. PubChem Database. Sodium hydroxide, CID=14798, https://pubchem.ncbi.nlm.nih.gov/compound/Sodium-hydroxide (accessed on Feb. 7, 2020)...