Chemistry 225 An Unknown Binary Mixture

Name Gabor Pohl Chemistry 225 An Unknown Binary Mixture

INTRODUCTION

Organic chemist identify compounds using techniques that aid in the identification of functional groups. This lab’s objective is to separate a two-component mixture using extraction techniques to separate liquid from solid, and then chemical tests such as saturation test, Lucas test, Tollen’s test,etc.. to confirm the presence of the functional groups. Infrared spectrometry and NMR are used to create a list of possible functional groups before beginning the chemical tests.

METHODS/PROCEDURE:

Mixture 84 was a solid-liquid mixture. The first step was to perform vacuum filtration in order to separate solid phase from liquid. The next step was to further purify both substances.Distillation is used to purify the liquid, so this was set up first because of the time it takes to complete. While simple distillation was happening, the solid was recrystallized in order to receive purer substance. A purer substance is preferred because the less contaminants present in to compound, the more accurate functional group testings and melting point recordings are, and therefore the more accurate the identification of the compound becomes. After both solid and liquid were purified, they were dissolved in dichloromethane and run through the IR spectrometer. The IR spectrum for both the solid and liquid phases was analyzed for distinct peaks. Based on those peaks, a list of possible functional groups was created, and chemical tests were that would confirm or reject these possibilities.The first test run on both solid and liquid was a solubility test with hydrochloric acid, sulfuric acid, water, sodium hydroxide, and bicarbonate. Testing to see in which solvent the unknowns are soluble in allows one to classify if the unknown is an acid, base, or neutral compound. Based on the findings listed in Table 1, one had an idea of which functional groups to test for. Those tests and the results are documented in Table 1.

RESULTS & OBSERVATIONS:

Table 1 Solid #84Liquid #84 Melting Point or Boiling

Point:

Melting Point: 157 -160

℃ ℃

Boiling Point: 118 -119

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Solubility Test: H2O: Insoluble

NaOH: Soluble

HCO3: Insoluble

HCl: Insoluble

H2SO4: Soluble

H2O: Insoluble

NaOH: Insoluble

HCO3: Insoluble

HCl: Insoluble

H2SO4: Soluble

Saturation Test: NegativeNegative

Lucas Test for alcohol:N/ACloudiness after two minutes

of adding the Lucas reagents to liquid Ferric Chloride Test for

Phenol:

Color change to purple upon addition of solid.N/A Sodium Bicarbonate test for Carboxylic Acids Formation of small bubblesN/A

NMR & IR Spectroscopy Results:

Solid Unknown #84 Liquid Unknown #84

NMR:●Shift at 1.0249

●Shift at 1.000 ●Shift at 1.9856 ●A shift labelled 3.0900 with three splits.●A shift labelled 3.1202 with two splits ●A shift labelled 4.1161 with multiple splits

IR Spectroscopy: ●A peak at 1655.9

●A peak at 1439.32 ●A peaks at 3233.55 ●Peaks at 3009.50 and

2998.30

●A broad, wide peak at

3327.42

●Two peaks at 2964.06 and 2876.94 ●A peak at 1370.4

TREATMENT OF RESULTS

Unknown Solid #84:

The first test conducted in order to begin testing for functional groups, was the solubility test. The solid was insoluble in water, soluble in sodium hydroxide, insoluble in bicarbonate, insoluble in hydrochloric acid, and soluble in sulfuric acid. When following the solubility chart, it was concluded that the compound was a weak acid and that a test for phenols should be carried This study source was downloaded by 100000857952895 from CourseHero.com on 12-12-2022 16:58:04 GMT -06:00

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out. I carried out the ferric chloride test for phenols which resulted in a purple color change, indicating the presence of a phenol.The IR spectrum showed peaks at 30009.50 to 2998.30 which could belong to a carboxylic acid and/or phenol O-H stretch. The peak at 1655.9 could also belong to a carboxylic acid C double bonded O stretch. In order to confirm the presence of a carboxylic acid, the sodium bicarbonate test was carried out, and resulted in the formation of bubbles which confirmed the presence of a carboxylic acid. The NMR had higher chemical shifts due to the acidic protons that can be due to the presence of the carboxylic acid. There are three types of hydrogens, containing doublets, meaning it’s neighbor has one hydrogen on the carbon next to it.The melting point of the solid was 157-160 . When choosing a derivative, salicylic ℃ acid had a melting point of 158 . This compound was used and tested using an amide ℃ derivative test which yielded a melting point of 159-161 .℃ From the results analyzed, it was concluded that unknown solid #84 was a phenol with a carboxylic acid attached on the ortho position to the alcohol of the phenol, such as carboxylic acid.

Unknown Liquid #84:

The first test conducted in order to begin testing for functional groups, was the solubility test. The solid was insoluble in water, insoluble in sodium hydroxide, insoluble in bicarbonate, insoluble in hydrochloric acid, and soluble in sulfuric acid. When following the solubility chart, it was concluded that the compound was a neutral compound. There are many neutral compounds, such as alkenes, alkynes, esters, ethers, alcohols, amides, ketones, aldehydes and nitro compounds. However, the IR spectrum showed a broad peak at 3327.42, indicating the presence of an alcohol. The peaks at 2964.06 and 2876.94 could be C-H stretches.Based on the IR and solubility tests, the unknown liquid was underwent the Lucas Test for alcohols. The test resulted in cloudiness after two minutes, which confirmed the presence of a secondary alcohol.The NMR showed a shift labelled 3.0900 with three splits, indicating a hydrogen connected to a carbon with two neighbors, meaning that carbon is connected to a CH2. The shift at 3.1202 with two splits indicated the presence of one neighbor, also known as a C-H bond.Lastly, the shift labelled 4.1161 with multiple splits indicates multiple CH2 bonds. Without a C- NMR, it is not possible to say how many CH2 bonds the unknown compound contains.The boiling point of the liquid was 118 -119 , which corresponded to 2-pentanol

℃ ℃

which has a listed boiling point of 119 from the list of derivatives. The 3,5-dinitrobenzoate ℃ test was carried out.

CONCLUSION

From the solubility test, the positive purple color on the ferric chloride test and the positive bubble formation of the sodium bicarbonate test, one can conclude that unknown solid #84 is salicylic acid. From the solubility test, and the positive cloudiness after two minutes from lucas test, one can conclude that unknown liquid #84 is 2-pentanol. This study source was downloaded by 100000857952895 from CourseHero.com on 12-12-2022 16:58:04 GMT -06:00

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