CHEZ 301 Extraction Full Lab Report PDF

Preview

Summary

A sample of the extraction full lab report...

Description

AIE CHEZ 301 06/28/2020 Extraction Lab Report

Abstract:

The components of phensuprin, sucrose, acetylsalicylic acid, and acetanilide, were isolated via acid-base extractions. Sucrose, acting as the binder, did not dissolve in the organic solvent and was recovered by gravity filtration. Acetylsalicyclic acid reacted with sodium bicarbonate to leave the acetanilide dissolved in the ethyl acetate, which was removed using a rotovap. The acetylsalicylate salt was neutralized using 6M HCl, and this compound was collected by vacuum filtration. The masses of all three compounds were measured, and the experimental percent composition was calculated. Melting points for each compound were taken on a Mel-Temp to assess purity and confirm identity.

Scheme 1. Reaction of acetylsalicylic acid with sodium bicarbonate followed by neutralization of the salt. 5% sodium bicarbonate solution was used for the extraction and 6M HCl was used for the neutralization. Sodium

bicarbonate deprotonates the carboxylic acid, but the resulting carbonic acid is unstable and decomposes to form water and carbon dioxide. 1 1 PerkinElmer Informatics, Inc. ChemDraw Professional, version 19.0.1.28, 2019.

Chemical Properties: Chemical

Hazards

Molar Mass (g/mol)

Melting Point (°C)

Boiling Point (°C)

Density (g/mL)

Acetanilide (CAS 103-84-4)

Irritant; do not ingest or inhale

135.16

113-115

305

1.22

Acetylsalicylic Acid (CAS 50-78-2)

Irritant; do not ingest or inhale

180.16

136

140

1.4

Sucrose (CAS 57-50-1)

none

342.3

185.5

102.82

1.59

Sodium Sulfate, Anhydrous (CAS 7757-82-6)

Corrosive. Irritant; do not ingest or inhale

142.04

884

1,429

2.66

Sodium Bicarbonate (CAS 144-55-8)*

Irritant; do not ingest or inhale

84.007

> 300

851

2.61

Ethyl Acetate (141-78-6)

Flammable, Irritant; do not ingest or inhale

88.11

−84

76.5-77.5

0.902

Hydrochloric Acid (CAS 7647-01-0)*

Extremely hazardous; may be deadly if swallowed,

36.46

-35

57

1.2

.

Chemical

Hazards

Molar Mass (g/mol)

Melting Point (°C)

Boiling Point (°C)

Density (g/mL)

Flammable, Explosive, Irritant; do not ingest or inhale Water (7732-18-5)

none

18.00

0

100

1.00

*Sodium bicarbonate was used as a 5% (w/v) sodium bicarbonate solution in water. 6M HCl was used prepared in advance for use in the experiment. 1. Sigma Aldrich Online Catalog. www.sigmaaldrich.com Accessed June 5, 2020.

Procedure2:

Phensuprin (1.264 g) was dissolved in ethyl acetate (25 mL). The solution was stirred for 1 min and the solid that did not dissolve was collected by gravity filtration. This filtrate was then extracted twice with 5% NaHCO3 (15 mL each time). The combined organic layers were dried over anhydrous sodium sulfate and the solvent was removed using a rotovap to leave a white powdery solid in the round bottom flask. The aqueous layer was cooled on an ice bath and 6M HCl was used to acidify the solution to a pH of 2 (by pH paper). The resulting solid was collected by vacuum filtration. The masses and melting points for each of the three solids were measured after they had been left to dry for a week.

Calculations: Percent Composition of Acetylsalicylic acid: •

(0.93 g acetylsalicylic acid / 1.264 g phensuprin) x 100 = 74% composition

Percent Composition of Sucrose: •

(0.291 g sucrose / 1.264 g phensuprin) x 100 = 23% composition

(Mass of solid (acetanilide) + round bottom flask) – (Mass of empty round bottom flask) = Mass of acetanilide: •

(70.373 g – 70.032 g) = 0.341 g of acetanilide

Percent Composition of Acetanilide: •

(0.341 g acetanilide / 1.264 g phensuprin) x 100 = 27% composition

Percent Recovery:

•

[(0.93 g acetylsalicylic acid + 0.291 g sucrose + 0.341 g acetanilide)/1.264 g phensuprin] x 100 = 124%

Results: The results concluded that the masses of all three components were 0.291 g sucrose, 0.341 g acetanilide and 0.93 g acetylsalicylic acid. The percent composition values were 27% acetanilide, 74% acetylsalicylic acid and 23% sucrose. The masses of all three components totaled resulted in a percent recovery of 124%. The melting points that were used to test the purity of all three components ranged between 175.6°C-179.8°C for acetylsalicylic acid (aspirin), 95.4°C-102.3°C for acetanilide and 130.5°C-134.1°C for sucrose. The literature melting point values were 136°C for acetylsalicylic acid, 185.5°C for sucrose and 113-115°C for acetanilide.

Discussion: For this experiment we used the method of extraction. Extraction is a method used with different components by solubility to obtain a purer substance. Phensuprin was separated into three components of acetylsalicylic acid, sucrose, and acetanilide. Phensuprin is an analgesic that was separated so that it could be analyzed. An acid-base reaction occurred after sodium bicarbonate was added. The acid-base reaction was useful to the experiment because it allowed for a water soluble salt and water to be form. This result helped us extract the acetylsalicylic acid and sucrose. During extraction of acetanilide a rotovap was used to form the solid through the evaporation of ethyl acetate. After the extractions, percent compositions was calculated from each of the three components. These compositions were 23% for sucrose, 74% for acetylsalicylic acid and 27% for acetanilide. The melting points ranged from 175.6°C-179.8°C for acetylsalicylic acid, 95.4°C-102.3°C for acetanilide and 130.5°C-134.1°C for sucrose. The total

percent recovery calculated from all three components was 124%. This result could be due to several different errors in the experiment. One example of a possible error is that during filtration and extraction components could have been lost. Another possible error could have been due to the ranges of the melting points from all three components being slightly lower than the literature melting point values indicating that there were impurities in our substance, which resulted in an improper percent recovery value.

Questions: Answer the following questions to be graded along with the full lab report. 1. Suppose you want to separate a mixture of the following compounds: salicylic acid, o-cresol, p-aminoacetophenone, and naphthalene. Come up with a list of steps and chemicals needed to most efficiently isolate all four compounds as solids with the greatest purity possible. You do

not need to write a formal procedure, but be sure to indicate steps needed clearly and in order. You can use a diagram or flow chart if you prefer. 1

Sneden, A., Moses, M., Franklin, C. 301 Expt 3 – Acid-Base Extraction Background, www.blackboard.vcu.edu (accessed June 23, 2020).

2. In the procedure, the bicarbonate solution was acidified with HCl to precipitate out acetylsalicylic acid. Why wasn’t the water removed by a rotovap instead? • In the presence of an acid or a base acetylsalicylic acid will undergo ester hydrolysis to produce salicylic acid at a high temperature. Because of this high temperatures were avoided during the procedure; therefore, further evaporation will remove the water.

References: 1. PerkinElmer Informatics, Inc. ChemDraw Professional, version 19.0.1.28, 2019. 2. Sneden, A., Moses, M., Franklin, C. 301 Expt 3 – Acid-Base Extraction Background, www.blackboard.vcu.edu (accessed June 23, 2020)....