Lab 2: Separation of a Mixture of a Carboxylic Acid and a Hydrocarbon PDF

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ochem 1 lab 2...

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9.10.2020, CHEM 3105-384 Lab 2: Separation of a Mixture of a Carboxylic Acid and a Hydrocarbon

Purpose The goal is to separate and purify a mixture containing a carboxylic acid and a hydrocarbon.

Reaction & Physical Properties Table

Reagents/Compounds/Solvent s benzoic acid o-chlorobenzoic acid naphthalene biphenyl diethyl 2 M NaOH (aq) 6 M HCl (aq) saturated NaCl (aq)

Volume (mL)

30 5 2 10

Density (g/mL) 1.3 1.544 1.16 1.041 0.71 2.13 1.19 2.17

Boiling point (°C) 249.2 285 218 256 35 1388 -85.05 1465

Safety SDS found at beta-static.fishersci.com Benzoic acid (corrosive, health hazard, irritant) Hazard statements: Causes skin irritation, causes serious eye damage, causes damage to organs through prolonged or repeated exposure Precautionary statements: If medical advice is needed, have product container or label at hand. Keep out of reach of children. Read label before use. Wear protective gloves/protective clothing/eye protection/face protection. Do not breathe dust/fume/gas/mist/vapours/spray. Wash thoroughly after handling O-chlorobenzoic acid (irritant) Hazard statements: Causes serious eye irritation. Precautionary statements: IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Naphthalene (explosive, flammable, irritant) Hazard statements: Heating may cause a fire or explosion. May cause an allergic skin reaction. Causes serious eye irritation Precautionary statements: If medical advice is needed, have product container or label at hand. Keep out of reach of children. Read label before use. Keep away from heat/sparks/open flames/hot surfaces. No smoking Keep/Store away from clothing/combustible materials. Keep only in original container. Avoid breathing dust/fume/gas/mist/vapours/spray

Biphenyl (irritant) Hazard statement(s) H303 May be harmful if swallowed. Causes skin irritation. Causes serious eye irritation. H335 May cause respiratory irritation. Very toxic to aquatic life. Precautionary statements: Avoid breathing dust/ fume/ gas/ mist/ vapours/ spray. Avoid release to the environment. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Ethyl Ether (health hazard, flammable, irritant) Hazard statements: Extremely flammable liquid and vapour. May be fatal if swallowed and enters airways. Harmful if swallowed. Causes serious eye irritation. May cause drowsiness or dizziness IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician Rinse mouth Fire In case of fire: Use CO2, dry chemical, or foam for extinction Storage Store locked up Store in a well-ventilated place. Keep container tightly closed Disposal: Dispose of contents/container to an approved waste disposal plant IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician Rinse mouth Fire In case of fire: Use CO2, dry chemical, or foam for extinction Storage Store locked up Store in a well-ventilated place. Keep container tightly closed Disposal: Dispose of contents/container to an approved waste disposal plant IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician Rinse mouth Fire In case of fire: Use CO2, dry chemical, or foam for extinction Storage Store locked up Store in a well-ventilated place. Keep container tightly closed Disposal: Dispose of contents/container to an approved waste disposal plant *Dispose of chemicals in an approved disposal area designated by the professor or TA.*

Procedure

1. Put 40 mL of the 2M NaOH in an Erlenmeyer flask. Then use ice bath to cool. 2. Use balance and weigh out 0.5 grams of

unknown. Record how much it was. 3. Add 30 mL of ether through the funnel. Swirl flask to dissolve. 4. Add NaOH to ether in 5-10 mL portions. Use pH paper to check if it’s basic. If not, add NaOH. 5. Remove stopper and pour into an Erlenmeyer flask labeled “Basic Extract”

6. Add water (10 mL) to wash the organic layer. Drain into “basic extract”. 7. Pour ether layer into flask labeled “Ether Wash” 8. Return the basic extract and add 10 mL of fresh ether to wash it. Drain back into extract 9. Add ether wash. Drain the wat 1. Put 40 mL of the 2M NaOH in an Erlenmeyer

flask. Then use ice bath to cool. 2. Use balance and weigh out 0.5 grams of unknown. Record how much it was. 3. Add 30 mL of ether through the funnel. Swirl flask to dissolve. 4. Add NaOH to ether in 5-10 mL portions. Use pH paper to check if it’s basic. If not, add NaOH.

5. Remove stopper and pour into an Erlenmeyer flask labeled “Basic Extract” 6. Add water (10 mL) to wash the organic layer. Drain into “basic extract”. 7. Pour ether layer into flask labeled “Ether Wash” 8. Return the basic extract and add 10 mL of fresh ether to wash it. Drain back into extract

9. Add ether wash. Drain the wat 1. Use balance and weigh out 0.5 grams of unknown. #4 (0.5004 g) 2. Add 30 mL of ether to unknown sample. Swirl beaker to dissolve. 3. Add unknown and ether mixture to a separation funnel. 4. Swirl and hold upside down then open valve to release pressure under hood. 5. Mixture should be separated with obvious line between the acid and the base. Open valve and allow the base to flow into beaker underneath. Set aqueous layer aside for later step. 6. Empty remaining ether into a separate beaker. 7. Add NaCl to mixture and swirl until salt moves freely. 8. Use paper to create a filter and pour sample through, filtering out the salt 9. Placed beaker on a heat source. Use air to blow dry sample. 10. Scrap samples into vial for safe keeping for the next week’s experiment. 11. Add 1.5 mL of NaOH to the H2O mixture from step #5. Use pH paper to check if basic. If not, add more NaOH by the mL. 12. Use vacuum flask on a separatory funnel with a small filter paper on top. Turn on vacuum and pour mixture over paper. 13. Once filtration paper is dry, scrap sample off into flask and save for next experiment.

Data & Observations #4 unknown sample turned red upon initial mixture. This will help determine the unknown in the next lab. After adding the NaCl to the acid and heating/cooling it to a solid, it appeared to have a shiny ice-like texture. After adding the HCl to the base, the redness faded and the mixture appeared to have a flour-like texture with an orangish tint. *Mistake was made during lab- NaOH was added to incorrect sample by mistake. Dr. Mummadi resolved issue and enough of the sample was collected for following lab.

Calculations & Results

No calculations were used for this experiment. The mixtures were separated successfully. Due to this being a twopart lab, results have not yet been determined. The identification of the unknown will be identified in the following lab.

Conclusions/Discussion After completion of this experiment, separation of the hydrocarbon and an acid was successful. The solutions were separated easily due to very different densities as well as obvious color difference as the base was deep red on the bottom and the acidic was clear on top.

Post Lab Questions 1. Why is sodium benzoate more soluble in water than benzoic acid? Sodium Benzoate is more polar than benzoic acid. 2. Why is biphenyl more soluble in diethyl ether than water? Biphenyl is neutral aromatic compound that is most soluble in organic solvent like diethyl ether and insoluble in water because like dissolves like. 3. What solvent (diethyl ether or water) would glucose (shown below) be most soluble in? Why? Glucose is very hydrophilic and dissolves readily in water. Glucose forms hydrogen bonds with water 4. Outline a procedure for separating anthracene and indoline (shown below) using extraction and possibly acid/base chemistry. 1. Add ether to solution. 2. Add diluted HCl. 3. Shake the mixture. 4. Separate into the two layers (organic and water). 5. With the ethyl layer add sodium sulfate and filter it out. Be sure to let the mixture evaporate before moving. 6. With the water layer add diethyl ether and a diluted NaOH. 7. Separate the water and ether layer. 8. With the ether layer add anhydrous sodium sulfate. Filter the mixture and allow the excess liquid to evaporate....