questions of the day: what is the functional group of carboxylic acids anhydrides esters amides...
Post on 21-Dec-2015
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Questions of the day:
What is the functional group of Carboxylic Acids
Anhydrides Esters
Amides
Amines Nitro???
Preliminary test results?
Mp., bp. Which would you expect to have relatively high/relatively low mp.s / bp.s?
Odor Which would you expect to have a bad smell/a pleasant smell (human perspective…)
Color Which would you expect to have a color?
• Preliminary tests?
• Solubility
• Classification tests
• Derivatives
• Spectra
Carboxylic Acids Anhydrides Esters Amides Amines Nitro
• the ratio of the velocity of light in air to the velocity of light in a given medium.
• sin incident angle/sin refracted angle
• a constant at a given temperature.
• an important physical property of liquids (and gases and transparent solids!)
• Air has a refractive index of 1.000292 at 273 K/760 mm Hg for the yellow sodium D-line at 589.3 nm.
Refractive Index:
What type of information do you get if your unknown
1. is soluble in water?
2. is soluble in NaOH and in NaHCO3?
3. is soluble in NaOH only, not in NaHCO3?
4. is soluble in dilute HCl solution?
5. is soluble only in conc H2SO4?
6. is not soluble in any of the above solvents?
Solubility Tests
Carboxylic Acids Anhydrides Esters Amides Amines Nitro
• Preliminary tests
• Solubility?
• Classification tests
• Derivatives
• Spectra
Carboxylic AcidsGood mp.s (consider recrystallization)
Neutralization Equivalent (titration) experimental instructions on our webpage
• Solubility
• Classification tests
• Derivatives (not done)
• Spectra
Derivatives (we do not do them in the lab):
Convert carboxylic acid into acid chloride first, then into amides
RCO2H + NaOH RCO2(–) Na(+)
aq. + H2O
1.
2.
+ HCl
Esters
Classification Test
Deep-red to purple
• Preliminary tests?
• Solubility
• Classification tests
• Derivatives
• Spectra
Compare with known ester!
a hydroxamic acid
Derivatives for Esters
Hydrolyze (experimental instructions on our webpage)
… to its carboxylic acid component (mp.)
…. and its alcohol component alcohol derivative
• Preliminary tests?
• Solubility
• Classification tests
• Derivatives
• Spectra
Amines
Derivatives
Picrates
Benzamides: amine + benzoyl chloride
NH 2
OH
NO 2
NO 2
O 2 N
+
• Preliminary tests?
• Solubility
• Classification tests
• Derivatives
• Spectra
Carboxylic Acids
IR:
H-NMR:
• Preliminary tests?
• Solubility
• Classification tests
• Derivatives
• Spectra
OH in gas phase(non-H-bonded)
Nitro Compounds Typical properties?
Classification test:
Always do with a known compound to compare!
Derivatives (if no other functional group available):
Reduce to amine and then prepare amine derivatives
• Preliminary tests?
• Solubility
• Classification tests
• Derivatives
• Spectra
Iron (II) Hydroxide Test for Nitro GroupsNitro Compounds
• IR
• UV
• MiniQuiz on today’s class
• Inert Compounds:
AlkanesAromatic Hydrocarbons
Alkyl halides
Next time: