BRANDEIS UNIVERSITY
CHEMISTRY 29A
PRELAB WRITEUP AND EXPERIMENTAL REPORT SHEET
NAME Richard Fan______________ T.A.'S NAME
David Gay_______________________________
DATE 8/2/06________EXPERIMENT# ___8___TITLE ___Polymerization of Nylon___________________
PURPOSE Polymerizing nylon from a reaction of sebacoyl chloride with 1,6-hexane diamine_______________
PRELIMINARY WRITEUP:
Materials:
0.25g Sebacic acid
0.25mL thionyl chloride
N,N-dimethylformamine
0.25g 1,6-hexane diamine
6mL water
1mL NaOH
12mL methylene chloride
%yield = experimental/theoretical × 100%
Acetone, methanol
Formic acid, hexane
Reaction tubes, beakers
Gas trap setup
Sandbath, wire
EXPERIMENTAL PROCEDURES*
(Include in preliminary writeup.)
-Place beaker of hot water on sandbath, set to 5.
-To reaction tube, add 0.25g Sebacic acid and 0.25mL
thionyl chloride (cap thionyl chloride when not in
use).
-Set up gas trap as shown.
-Set thermometer in hot water bath, when temperature
is 60º-70ºC, add 2 drops of N,N-dimethylformamine
to reaction tube mixture. Quickly cap the tube with the
gas trap and let heat in water bath for 15 minutes.
-While reaction is being heated, coat a 30mL beaker
with silicone grease.
-In greased beaker, prepare mixture of 6mL water,
1mL NaOH, 0.25g 1,6-hexane diamine, 10mL
methylene chloride.
-After 15 minutes of heating, add 2mL methylene
chloride to reaction tube. Float this solution on top of
the beaker solution.
-Use a wire to pull out the nylon, drag along lab
bench. Record the length of the longest piece and total
weight for percentage yield.
-Perform solubility test in acetone, methanol, formic
acid, and hexane.
theoretical yield =
weightsebacic acid/MWsebacic acid × MWfinal product
Thionyl chloride
Sebacoyl chloride
MW 118.97
MW 239.14
Density 1.64g/mL
BP 168ºC
BP 79ºC
1,6-hexane diamine
Sebacic acid
MW 116.21
MW 202.25
MP 45-46ºC
MP 137ºC
Nylon 6.10
MW 282.43
(monomer)
MODIFICATIONS AND OBSERVATIONS*
(Obtained from the lab experience)
The mixture of solid Sebacic acid and aqueous thionyl chloride produced
an aqueous solution. The appearance of the liquid after 15 minutes of
heating was expected to be clear with a small liquid layer on the bottom of
the tube. Instead, the solution was a slightly dark and cloudy solution with
a bead of immiscible liquid on the bottom. The tube was flicked to mix the
solution, but there was no change in appearance. This was thought to be
due to an incomplete reaction, and one additional drop of thionyl chloride
and two additional drops of N,N-dimethylformamine were added to the
reaction tube. This made no change to the appearance of the solution The
rest of the experiment was then carried out according to procedure. After
heating, 2mL of methylene chloride was added to the reaction tube, and
this mixture was slowly poured down the side of the greased beaker on top
of the 1,6-hexane diamine mixture. As it was being poured, some reaction
was already starting as evident in the vapors observed near the mouth of
the reaction tube. As the two mixtures came into contact, a continuous
white polymer formed. The first attempt to extract this polymer with a
wire yielded a large flat piece that came out at once without forming a
rope shape. Further attempts yielded a longest piece of 184cm. Together,
the total nylon yield was 0.817g, which still contained some amount of
water despite pressing dry on filter paper. The results of the solubility tests
showed that the polymerized nylon was soluble only in formic acid.
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RESULTS, DISCUSSION AND CONCLUSIONS*
There are two separate reactions in this experiment used to create polymerized nylon. The first involves the reaction of thionyl
chloride with sebacic acid. This reaction chlorinates the terminal hydroxyl positions on the sebacic acid molecule to create
sebacoyl chloride. The HCl and SO2 by-products are gaseous and collected in a gas trap. These by-products then react with water
from the cotton plug to form aqueous HCl and HSO 3, which then remain in the gas trap. Once the diacid chloride has been
formed, it is reacted with 1,6-hexane diamine to form the film of polymerized nylon. This second reaction process occurs at the
interface of the two immiscible liquids (sebacoyl chloride in water solution and 1,6-hexane diamine in methylene chloride
solution) because this is the point at which the 1,6-hexane diamine can come into contact with the diacid chloride. While the two
solutions are not miscible, the diamine is soluble in both the water and organic solvents, allowing it to diffuse from the organic
solvent into the water solvent in which the sebacoyl chloride is dissolved, and react with it in this interfacial region. After the
nylon was formed, it was pulled out with a piece of copper wire, but due to the formation of a large piece of the nylon, no stringshaped piece could be pulled out at first. This result most likely had to do with the rate at which the final reaction occurred. If the
sebacoyl chloride had been added more slowly to the 1,6-hexane diamine solution, there would have been less disruption to the
interfacial region , leading to a slower reaction. In that case, the nylon would be able to polymerize as it is being pulled out of the
beaker to form a longer continuous strand. In the experiment however, too much of the sebacoyl chloride was poured in too
quickly, resulting in unnecessary mixing of the two solutions and promoting premature polymerization of a larger amount of
nylon.
ANSWERS TO END-OF-CHAPTER QUESTIONS*
#2 – ClC=O(CH2)8C=OCl + 2H2O  HOOC(CH2)8COOH + 2HCl
#4 –
A – The nylon 6.10 polymer is made up of some number of the monomer attached to each other. This means
that the unknown weight of the nylon polymer is a multiple of the molecular weight of the 6.10 monomer.
For instance, if 1mmol of the limiting reagent is used, then 1mmol of the nylon monomer can be expected to
be produced, totaling 0.282g (1mmol × 282.43g).
B – The interfacial polymerization describes the joining together of the nylon monomers (nylon
polymerization) at the contact point between two reacting layers of solutions (at their interface). The two
solutions are not miscible, but one compound (here, 1,6-hexane diamine) is soluble in both solutions and is
able to diffuse across and react at the interface.
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