Organic Chemistry 102
Lab Schedule and Review
Fall 2003
Exp.
#
1
2
Description
Introduction to lab,
Safety
Writing lab reports,
Melting Point
Simple and
Fractional Distillation
Refractive Index
3
Molecular modeling
Lab
4
Recrystallization
5
Liquid-liquid
extraction
Ref. & Reading assignments
(Things you should know for exam)
p. 1-29
Review safety section; refer to notes on specific topics.
Notebook preparation: read section and review handout.
Tech. 6, Part A, Handout
Melting point theory; energy changes; mixed melting point; eutectic; problems and
solutions.
Exp. 6, Handout
Tech. 8,10,18
Review techniques 8 and 10 on simple and fractional distillation. Be familiar with
different types of apparatus used and the names and uses of the components of a
distillation apparatus (see notes). Be able to read/construct a phase diagram using
Raoult’s Law for a particular binary system. Know about non-ideal systems:
azeotropes both minimum and maximum; and how to use a phase diagram from these.
Be familiar with the types of columns used in fractional distillation, factors such as
theoretical plates; HETP, hold-up, etc., in choosing a particular column for a
separation (see notes and handout).
What is a refractometer and why did we use it? How does it work, in general.
Essay pp. 166-172; Exp. 16; Handout
Review handout and Essay; know the advantages and limitations of using a MM
program like PCModel.
Handout; Tech. 5
Understand the major steps in crystallization and why it works so well for most solids.
Be able to list the steps and describe each one in detail. Know both semi-micro and
Microscale methods and the equipment used for both. Know the advantages of a Craig
Tube. Be able to list and explain the several factors that go into an “ideal” solvent (see
notes). Understand and be able to pick the best solvent for a recrystallization based on
solubility/polarity characteristics of solute/solvent. Know what solvent will not work
for a particular solute. Understand how to use a mixed solvent system for
recrystallization (Tech. 5.9). Know about and how to solve the following problems:
insoluble impurities, soluble impurities, colored impurities, oiling out (know all
possible causes and solutions), supersaturation, rapid crystal formation. Know how,
when and why hot filtration and vacuum filtration are done. Know the following
terms: crystallization vs. precipitation, solubility gradient, mother liquor, filtering
pipet, fluted filterpaper, Norit, Hirsch funnel, stemless funnel, 2nd crop, 3rd crop.
Tech. 7; Handout
Know components of an extraction, and the requirements for a good extraction. Be
able to generate/use a distribution (partition) coefficient and estimate one based on
relative solubilities of a solute in the two solvents. Understand and be able to
demonstrate why several small volume extractions are better than one large extraction.
Be familiar with the different techniques/apparatus used for extractions. Know when
the aqueous layer will be on top or bottom. Be able to describe the proper use of a
separatory funnel, centrifuge tube extraction method, etc. How do you avoid, break-up
an emulsion? Be able to use and draw an extraction diagram showing how a mixture
of compound may be separated using aqueous solutions of different pH. Be able to
write the chemical equations that are being carried out in each step of the separation,
and which ones to do first. Amines, carboxylic acids, phenols, etc. Do not forget to
regenerate and purify each separated component. Know why and how we use drying
agents. Know several of the more common ones and how they work. When and why
do you use a saturated NaCl (brine) solution?
6
Natural product
isolation, sublimation
Caffeine from tea
Exp. 11; Tech. 7, 16
Understand the main steps used in this experiment. Why were they done?
Exp. 10, Tech. 14
Know the analgesics used in the experiment and their advantages. Understand the
theory of chromatography: mobile and stationary phases and partitioning of the solute
between them. Be able to predict relative Rf values for a group of compounds, given a
TLC system. Know the several steps of a TLC experiment and the options in each.
Visualization is an important part of the experiment; know the methods and
advantages/disadvantages. In setting up an analysis, know what solvents would be
used to allow for a better method/separation.
Handout; Tech. 11, 17.
Understand how steam distillation works to purify natural products from the natural
sources. Be able to explain the theory of steam distillation where the each liquid
(water and organic) exerts its own vapor pressure, independent of the other. Be able to
compare this to the distillation of a normal mixture where the vapor pressures are
modified by their mole fractions (Raoult’s Law). Know the two different methods of
steam generation: direct and live steam methods. We used the direct method on a
macroscale (see fig. 11.4 p. 667) apparatus.
Know how a polarimeter works, by taking plane polarized light and passing it through
a sample, measuring the optical rotation of the plane of light. Be able to calculate the
specific rotation from the observed rotation and concentration data. With this also be
able to determine the optical purity and enantiomeric excess in a sample.
7
Thin-Layer
Chromatography
8
Natural Product
Isolation, Limonene;
Steam Distillation ;
Polarimetry
9
Synthesis of n-Butyl
Bromide;
Infrared spectroscopy
Exp. 21A; Appendix 3
Lab Exam
Over all techniques and experiments 1-8