Experiment 7-9 Lab Report PDF

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Identification of Unknown Organic Compound Purpose: The purpose of this lab is to collect qualitative data on an unknown compound in order to discover the identity of the unknown via various properties. In this case, the unknown was S23. Physical Properties Table and Flowchart Image obtained from TopHat Safety Data

Physical Properties of Unknown as discovered experimentally Color Odor Melting Point Boiling Point Unknown Colorless No Compound 43oC 201oC (S23) solid noticeable odor Safety: Obtained from TopHat Safety Data Chemicals present are hazardous and should be treated as such. Be sure to wear all proper protective gear and follow all safety guidelines. Take care to not touch personal items that could cause chemical contamination. 2,4-Dinitrophenylhydrazine (Flammable) Risk statements: Explosive when dry. Flammable solid. Causes eye irritation. May be harmful if swallowed. May cause skin and respiratory tract irritation Safety Statements: In case of contact, flush skin with plenty of water. Remove contaminated clothing and shoes. If inhaled, remove to fresh air Tollens Reagent (Irritant) Risk Statements: May be corrosive to metals Harmful if swallowed Causes skin irritation Causes serious eye irritation Safety Information: In case of contact, flush skin with plenty of water. Remove contaminated clothing and shoes. If inhaled, remove to fresh air Jones Reagent (Chromic Acid) (Irritant) Risk Statements: May be corrosive to metals Harmful if swallowed Causes skin irritation Causes serious eye irritation

Safety Information: In case of contact, flush skin with plenty of water. Remove contaminated clothing and shoes. If inhaled, remove to fresh air Cerium Nitrate (Irritant) Risk Statements: May be corrosive to metals, harmful if swallowed, causes skin irritation Causes serious eye irritation Safety Information: In case of contact, flush skin with plenty of water. Remove contaminated clothing and shoes. If inhaled, remove to fresh air Bromine Water (Corrosive) Risk Statements: Causes severe skin burns and eye damage, fatal if inhaled, very toxic to aquatic life Safety Statements: In case of contact, flush skin with plenty of water. Remove contaminated clothing and shoes. If inhaled, remove to fresh air Ferric Iron (Irritant) Risk Statements: May be corrosive to metals, harmful if swallowed, causes skin irritation Causes serious eye irritation Safety Statements: In case of contact, flush skin with plenty of water. Remove contaminated clothing and shoes. If inhaled, remove to fresh air Copper Sulfate (Irritant) Risk Statements: May be corrosive to metals, harmful if swallowed, causes skin irritation Causes serious eye irritation Safety Statements: In case of contact, flush skin with plenty of water. Remove contaminated clothing and shoes. If inhaled, remove to fresh air 4-Methylaniline (Irritant) Risk Statements: May be corrosive to metals, harmful if swallowed, causes skin irritation Causes serious eye irritation Safety Information: In case of contact, flush skin with plenty of water. Remove contaminated clothing and shoes. If inhaled, remove to fresh air Procedure Experiment 7: 1. Amber bottles are located in the hood, obtain one vial of liquid unknown and one vial of solid unknown and label with unknown number. 2. First, observe color, odor, and melting point of unknown (if not given) Obtain boiling point as well if not given by TA 3. Begin with water solubility test. If positive follow the green path, negative follow the red path. 4. For solid sample, use 15mg and add 1 ml water to test for solubility, once added stir vigorously 5. For liquid, add few drops of unknown to test tube containing 1 ml water and mix, if using shell vial, can be capped and shaken. If liquid soluble should have clear solution with non layers. 6. If water soluble, start a pH test by dipping a drop on pH paper 7. If water insoluble, test for solubility in 5% NaOH solution. If soluble, test in 5% NaHCO3 8. If 5% NaOH insoluble, test for solubility in 5% HCl 9. Have your TA obtain an IR spectrum for the unknown Experiment 8:

1. To perform a 2,4-Dinitrophenylhydrazine Test use a sport plate to add 1-2 drops of the unknown with 7-8 drops of DNP test solution to a well. Mix with stirring rod or pippet. If positive should form a precipitate and turn red or bright yellow 2. To perform tollens test Add ~1 mL of the Tollen's reagent solution to a shell vial. Add 1 drop of liquid unknown or a tiny bit of solid unknown. Cap the vial and shake vigorously. Allow the mixture to stand. If the unknown is an aldehyde, the solution will start darkening within one to two minutes and will likely form a silver mirror on the surface of the vial within a few minutes 3. To perform jones oxidation Use a spot plate for this test. Add 1 drop of liquid unknown or 10 mg of solid unknown and dissolve it ~10 drops of acetone. Add a drop of the Jone's reagent carefully. Some reactions can be very exothermic resulting in splattering of reagent. If something is oxidized by the chromium (VI) salt, the chromium will be reduced to a green chromium (III) salt. 4. To perform copper sulfate test On a spot plate add 7-10 drops of Cu(SO4) (10%, aq) followed by 10 mg of solid or 1 drop of liquid unknown. Mix with stirring rod or pipet and observe any changes to the solution. 5. To perform ferric iron test Add 2-3 drops of water to a white spot plate, 1-2 drops of ethanol. To this solution add the unknown liquid (2 drops) or solid (10 mg) and stir with a glass rod. To the resulting solution, add 1 drop of ferric chloride (2.5% FeCl3) and look for any drastic change of color that would indicate a postive result. If no color change occurs after stirring for 1 minute, add a second drop of ferric chloride and stir again for an additional minute. The color may not persist and could be only temporary, and excess ferric chloride coud lead to changes in the complexation and also reverse the color change. Pyridine can also be used for the same test. Experiment 9: 1. Add 10 drops of aniline and ~1 mL of CH2Cl2 to a 5 mL conical vial. Add a spin vain, long pointy end down. Cool the mixture in an ice bath. In the hood with stirring slowly add the crude acid chloride solution to the stirring chilled aniline solution. Allow mixture to stir for 10 minutes. 2. Extract the CH2Cl2 solution with ~1 mL of H2O, followed by ~1 mL 5% HCl(aq), followed by ~1 mL 5% NaOH(aq), and finally ~1 mL of H2O. All of the aqueous solutions will be the top layer during the extractions. Additional CH2Cl2 can be added if needed. The mixture can be transferred to a centrifuge tube if that is easier to complete the extractions. 3. Dry the organic solution with a minimal of anhydrous MgSO4. If the solution cannot be easily decanted from the solid MgSO4, a pipette with a tiny bit of cotton can be used as a filter. Remove the solvent in the hood with gentle heating and compressed air. 4. Recrystallize the solid from hot ethanol/water. heating the solid in ~1 mL of ethanol until it starts to boil. Do not set the hot plate above 120oC. Watch the solution in case it tries to boil over since there are no boiling chips present. All of the solid should dissolve. If it doesn't, more ethanol may be needed Once the solution is hot slowly add water. Put the vial back on the hot plate between water additions. Solid will look like it is trying to come out of solution briefly and then goes back into solution.. When the solid is just barely going back into solution with swirling, stop adding water and allow the solution to cool to room temperature.

5. Collect the crystals by vacuum filtrate using your Hirsch funnel and 10 mm filter paper. The crystals may be pressed on filter paper to help speed drying. Obtain a melting point and compare the value to that in the blue book. 6. For amides Add a spin vane to a conical vial followed by ~0.5 mL of 10% NaOH(aq) and 50 mg of amine (~5-6 drops if liquid). In the hood rapidly stir and add 5-6 drops of benzoyl chloride drop wise. Stir mixture for 10 minutes. 7. Collect the crystals by vacuum filtrate using your Hirsch funnel and 10 mm filter paper. Rinse crystals with ~ 0.5 mL of dilute HCl(aq) followed by ~ 0.5 mL of water while they are still in the funnel with the water running. The crystals may be pressed on filter paper to help speed drying. Obtain a melting point and compare the value to that in the blue book.

Data/Observations: Experiment 7: Unknown was labeled S23

The presence of a medium peak at 3500cm-1 indicates a primary amine, later confirmed by further testing. The presence of a peak at 1615 might have indicated a unsaturated ketone but further tests proved this was not the case. Ir spectrum was not used to initially determine unknown but was used to compare and confirm unknown’s identity.

These two spectrums were obtained from the first experiment. Of these two, the H NMR was the easiest to begin interpreting. The peak splitting between 6-8ppm on the chart is a typical signal of a benzene ring. The area of 4 H’s shows that the benzene ring has 4 free carbons that attach to the hydrogens which means 2 other carbons will be bonded. The peak at 3-4ppm is a single peak that contains two hydrogens. It is in an integration that is typical of a carbon bonded to X, N, or O molecule. The peak at 2-3ppm has multiple bonds it could be but most likely is a carbon bonded to a carbon in a double bond A solubility test was also performed and the solid was not soluble in water but was soluble in ether. Experiment 8: S23 A 2,4-Dinitrophenylhydrazine Test was performed first to identify an aldehyde or ketone. The precipitate did not form, showing the lack of either functional group. A Jones Oxidation test was then performed. An extremely dark precipitate formed. This showed the possibility of either an aniline or phenol function group. The Ceric Nitrate test was then performed. A dark precipitate formed but was not red. This indicates that a phenol was not present as a functional group. The Copper Sulfate test formed a green precipitate on top when the reagent was added. This indicates the presence of an amine. A ferric ion and bromine water test was performed but neither had a reaction, indicating none had a functional group that fit the test.

Experiment 9: S23 Previous results from other tests showed a benzamide derivative was to be obtained in order to obtain a melting point. The crystals were obtained, and a melting point was found. The melting point experimentally was 43oC Using the information gathered from tests and spectrums, the blue book was used to identify the unknown as 4-methylaniline. Calculations/Results No Calculations done. Result of all experiments was S23 is 4-Methylaniline

Discussion/Conclusion The identification of the unknown, S23, first began by collecting properties of the unknown and spectrums to begin to know the structure of the unknown. The 1H NMR spectrum immediately gave insight into the unknown, as the splitting of the peak between 6-8ppm was a classic characteristic of a benzene ring. Only 4 carbons being present under this peak indicated that two of the carbons on the ring are bonded. The second peak at 3-4ppm indicates a carbon bonded to either a halogen, nitrogen, or oxygen. Two hydrogens under this peak mean that two hydrogens are bonded to this atom. The last peak between 2-3ppm has multiple bonds that it could be. The most likely bond is a CH3 bonded to a double bonded C atom. This would correlate to a benzene ring but further tests need to be done to be sure. The second experiment included many tests to determine a functional group. The first test to narrow down a functional group was the Jones Oxidation test. This produced a dark precipitate that was characteristic of either an amine or a phenol. A Ceric Nitrate test was done to determine if the phenol was present. It also produced a dark precipitate which is not characteristic of a phenol. This narrowed the functional group to an amine but a Copper Sulfate test was done to be sure. When a green precipitate was formed, the amine group was confirmed. Other tests where performed including ferric acid and bromide water but none showed the presence of an additional functional group. The last experiment was done to find the melting point using a benzamide derivative because an amide group was found in the previous tests. The crystals were obtained and the melting point experimentally was found to be 43oC. Collection of all this data and referencing the bluebook, the compound S23 was found to be 4-methylaniline. The structure follows both the 1H NMR and IR spectrums. The blue book

property of 45oC melting point was extremely close to the experimentally found value and the compound contains an amine, as found in experiment 8. Both spectrums were compared to online spectrums to confirm compound identity....