Experiment 3: Separation of a Mixture by Acid-Base Extraction

Chemical Safety Information:

**Possible Extraction Organic Compounds**
benzoic acid	trans-cinnamic acid	para-toluic acid
ethyl para-aminobenzoate	naphthalene	biphenyl
triphenylmethane

**Reagents & Solvents**
sodium hydroxide	hydrochloric acid	diethyl ether
ethanol	methanol	dichloromethane
deuterated-chloroform

Experimental Spectra:

Sample starting Mixture ¹H-NMR Spectra (for reference and pre-lab questions)

Mixture A: triphenylmethane, trans-cinnamic acid, and ethyl 4-aminobenzoate	Mixture B: naphthalene, benzoic acid, and ethyl 4-aminobenzoate	Mixture C: triphenylmethane, benzoic acid, and ethyl 4-aminobenzoate
Mixture D: naphthalene, p-toluic acid, and ethyl 4-aminobenzoate	Mixture E: biphenyl, p-toluic acid, and ethyl 4-aminobenzoate	Mixture F: triphenylmethane, p-toluic acid, and ethyl 4-aminobenzoate
Mixture G: biphenyl, benzoic acid, and ethyl 4-aminobenzoate	Mixture H: naphthalene, trans-cinnamic acid, and ethyl 4-aminobenzoate	Mixture I: biphenyl, trans-cinnamic acid, and ethyl 4-aminobenzoate

Authentic Spectra of Mixture Components (for reference, not available for submission for credit)

triphenylmethane (¹H-NMR, ¹³C-NMR)	naphthalene (¹H-NMR, ¹³C-NMR)	biphenyl^{(1H-NMR, 13C-NMR)}
trans-cinnamic acid (¹H-NMR, ¹³C-NMR)	p-toluic acid (¹H-NMR, ¹³C-NMR)	benzoic acid (¹H-NMR, ¹³C-NMR)
ethyl 4-aminobenzoate (¹H-NMR, ¹³C-NMR)

Extracted Coumpound ¹H-NMR, 13C-NMR, GC-MS, and IR Stock data (available to submit for course credit, see lab manual for details)

Mixture A:

triphenylmethane (¹H-NMR, ¹³C-NMR)

trans-cinnamic acid (IR, ¹H-NMR)

ethyl 4-aminobenzoate
(IR, ¹H-NMR, GC-MS)

Mixture B:

naphthalene (¹H-NMR, ¹³C-NMR)

benzoic acid (IR, ¹H-NMR)

ethyl 4-aminobenzoate
(IR, ¹H-NMR, GC-MS)

Mixture C:

triphenylmethane (¹H-NMR, ¹³C-NMR)

benzoic acid (IR, ¹H-NMR)

ethyl 4-aminobenzoate
(IR, ¹H-NMR, GC-MS)

Mixture D:

naphthalene (¹H-NMR, ¹³C-NMR)

p-toluic acid (IR, ¹H-NMR)

ethyl 4-aminobenzoate
(IR, ¹H-NMR, GC-MS)

Mixture E:

biphenyl (¹H-NMR, ¹³C-NMR)

p-toluic acid (IR, ¹H-NMR)

ethyl 4-aminobenzoate
(IR, ¹H-NMR, GC-MS)

Mixture F:

triphenylmethane (¹H-NMR, ¹³C-NMR)

p-toluic acid (IR, ¹H-NMR)

ethyl 4-aminobenzoate
(IR, ¹H-NMR, GC-MS)

Mixture G:

biphenyl (¹H-NMR, ¹³C-NMR)

benzoic acid (IR, ¹H-NMR)

ethyl 4-aminobenzoate
(IR, ¹H-NMR, GC-MS)

Mixture H:

naphthalene (¹H-NMR, ¹³C-NMR)

trans-cinnamic acid (IR, ¹H-NMR)

ethyl 4-aminobenzoate
(IR, ¹H-NMR, GC-MS)

Mixture I:

biphenyl (¹H-NMR, ¹³C-NMR)

trans-cinnamic acid (IR, ¹H-NMR)

ethyl 4-aminobenzoate
(IR, ¹H-NMR, GC-MS)

Spectral Workup Instructions

A general guide for spectral workup in MestReNova has been created. Use it to guide you through your spectral analysis of the isolated carboxylic acid, isolated amine, and isolated unfunctionalized compound.

Chem 344 MestReNova Guide

A video is provided below to demonstrate the use of MestReNova for the preparation of one of the spectra. See the sample spectra below for examples of well-prepared spectra.

A general guide for spectral workup in MestReNova has been created. Use it to guide you through your spectral analysis.

Frequently Asked Questions:

Q1) How do I know which phase is organic layer and which is aqueous? How do I know which phase has which molecule?

A1) The extraction separation is based upon charge, polarity, and solubility. The solubility of the acidic or basic functional group can be manipulated by exploiting its reactivity with other bases and acids respectively. Via and acid/base reaction the changes in charge and polarity upon reaction for these species can be used to separate them due to their changes in solubility. The general flowchart of the separation is shown below. Read pages 3-8 to 3-10 in the lab manual.

Extraction Flow Chart

Q2) Why will MestreNova not open my fid file?

A2) The most common reason for this is that the license file is not properly installed. The file (mnova.lic) is available here and should be obtained by right-clicking and choosing save as. The image below shows what Mestrenova looks like when it is open with an unistalled license file. Notice the circled red X in the lower right corner.

After downloading the license file, you must activate it as a member of the University of Wisconsin Chemistry Department. This means that you must be connected properly, by one of two ways (renewed at least once every 90 days):

Using a network cable (not wireless), the computer is directly connected to the Chemistry Building.
Using WiscVPN (wired or wireless), the computer is connected to the campus network.

Without connecting by either of those methods, the license installation will fail and MestreNova will not open any fid data. See the complete directions on the spectroscopy and spectrometry page.

MestreNova License Error