Organic Chem
Organic Lab I No. 5-6
Separation of a Carboxylic Acid, a Phenol, and a Neutral Substance
(Two-week lab)
Reading Assignment
1) Chapter 7
• Introduction: P. 135- first paragraph
• Theory and Techniques (p142-145) o Properties of Extraction Solvents o Mixing and Separating the Layers o Drying Agents o Part 1: The Technique of Neutral Liquid/Liquid Extraction The description is for dichloromethane-aqueous solution mixture, but you will use the same technique for your tert-butyl methyl ether-aqueous solution mixture. Note, however, that the ether is less dense than water, while dichloromethane is denser than water. o Part 2: Acid/Base Liquid/Liquid Extraction (p.147-150 middle)
2) THIS HANDOUT: Scheme of Procedure and Reaction Equations
Reports
(1) Due the beginning of Lab No. 6: Answers to the post-lab questions (see below) (2) Due the beginning of Lab No. 7: Formal Report (see Guideline)
Post-lab questions
1. When you have a two-layer mixture of water and tert-butyl methyl ether, what physical property of these liquids assures you that ether is the top layer?
2. Explain how a phenol can be separated from a mixture of a phenol and a neutral compound using the acid-base extraction method.
3. In this separation experiment, you first extract a carboxylic acid with NaHCO3(aq), then extract a phenol with NaOH(aq). Can you reverse the order? Why or why not?
4. You perform each extraction twice, first with 1 mL and second with 0.15 mL. Why is the second extraction necessary?
5. What is the purpose of washing an ether solution with saturated NaCl solution?
6. What is the purpose of using CaCl2 pellets?
(More questions next page!)
7. a) If your carboxylic acid is benzoic acid, how many moles of benzoic acid are present in your sample? b) How many moles of sodium
Separation of a Carboxylic Acid, a Phenol, and a Neutral Substance
(Two-week lab)
Reading Assignment
1) Chapter 7
• Introduction: P. 135- first paragraph
• Theory and Techniques (p142-145) o Properties of Extraction Solvents o Mixing and Separating the Layers o Drying Agents o Part 1: The Technique of Neutral Liquid/Liquid Extraction The description is for dichloromethane-aqueous solution mixture, but you will use the same technique for your tert-butyl methyl ether-aqueous solution mixture. Note, however, that the ether is less dense than water, while dichloromethane is denser than water. o Part 2: Acid/Base Liquid/Liquid Extraction (p.147-150 middle)
2) THIS HANDOUT: Scheme of Procedure and Reaction Equations
Reports
(1) Due the beginning of Lab No. 6: Answers to the post-lab questions (see below) (2) Due the beginning of Lab No. 7: Formal Report (see Guideline)
Post-lab questions
1. When you have a two-layer mixture of water and tert-butyl methyl ether, what physical property of these liquids assures you that ether is the top layer?
2. Explain how a phenol can be separated from a mixture of a phenol and a neutral compound using the acid-base extraction method.
3. In this separation experiment, you first extract a carboxylic acid with NaHCO3(aq), then extract a phenol with NaOH(aq). Can you reverse the order? Why or why not?
4. You perform each extraction twice, first with 1 mL and second with 0.15 mL. Why is the second extraction necessary?
5. What is the purpose of washing an ether solution with saturated NaCl solution?
6. What is the purpose of using CaCl2 pellets?
(More questions next page!)
7. a) If your carboxylic acid is benzoic acid, how many moles of benzoic acid are present in your sample? b) How many moles of sodium