In this study, the chromatographic and spectroscopy evidence
about this reaction have been generated to verify this mechanism.
The applications of this derivatization reaction in polymer analysis
of (1) polyallylamine derivatized with acetonylacetone, (2) ethyl-
ene-carbon monoxide alternating copolymer derivatized with
methylamine, and (3) ethylene-carbon monoxide, styrene-
carbon monoxide alternating terpolymer derivatized with methy-
lamine have been demonstrated.
line pyrolysis interface for 5 min at 300 °C to evaporate any
nonpolymeric material (water, unreacted reagents). After this
cleaning procedure, the quartz tube was equilibrated for 5 min in
a 300 °C interface connected to the injection port of a Hewlett-
Packard (HP) model 5890 gas chromatograph equipped with a
HP 5970 mass-selective detector (MSD). The samples were
pyrolyzed (CDS 2000 Pyroprobe Pt coil) at an actual temperature
of 700 °C with probe calibration. The coil was heated to the set
temperature at 20 °C/ ms and held at the set temperature for a
20-s interval. The pyrolysis products were split in the 300 °C
injection port, with 10 psi head pressure, 30:1 split ratio, and
separated on a fused-silica capillary column (J & W Scientific DB-
EXPERIMENTAL SECTION
Reagent Sources. The poly(allylamine hydrochloride) (Cata-
log No. 28,321-5), methylamine, 40 wt % solution in water (Catalog
No. 42,646-6), acetonylacetone (Catalog No. A1,060-4), and 1,2,5-
trimethylpyrrole (Catalog No. T8,030-6) were purchased from
Aldrich Chemical Co., Inc. (Milwaukee, WI). All polymers and
reagents purchased were used without further purification. The
ethylene-carbon monoxide alternating copolymer and ethylene-
carbon monoxide, styrene-carbon monoxide alternating terpoly-
mer were synthesized in the laboratory on the basis of a literature
method.9 The alternating structures of both copolymer and
terpolymer have been verified by 13C NMR spectroscopy.
Derivatization Reaction. (1 ) Methylamine and Aceton-
ylacetone. A 2.0-g sample of acetonylacetone (orange color) was
mixed with 5.0 g of methylamine, 40 wt % aqueous solution (a
clear solution), in a reaction vial. The reaction takes place
immediately at room temperature. This reaction is exothermic as
evidenced by warming of the vial wall. When the reaction was
complete, the solution separated into two layers. The top layer is
the reaction product, 1,2,5-trimethylpyrrole, with a light yellow-
green color. The bottom layer is unreacted methylamine solution,
with a clear to light green color.
5
, 30 m × 0.25 mm i.d., 1.0-µm film) using a linear temperature
program (40 °C/ 4 min, 10 °C/ min, to 320 °C/ 18 min) and detected
by a MSD. The output from the GC was transferred through a
transfer line (300 °C) to the ion source of the MSD. An electron
ionization mass spectrum was obtained every second over the
mass range of 15-500 Da.
NMR Conditions. The 75.512-MHz 13C NMR spectra were
acquired using a Varian Inova 300 NMR spectrometer operating
at a field strength of 7.0527 T. The chemical shift scale was set
6 6
using an external shift reference; C D ) 128.39 ppm. Proton-
coupled 13C NMR spectra were acquired in order to determine
the carbon multiplicity.
Safety Considerations. The derivatization reagent is a com-
bustible liquid, neurologic hazard, and irritant. The liquid is readily
absorbed through skin. Any contact and inhalation should be
avoided. Personal protective devices should be used when
performing the derivatization reaction. The experiment should be
carried out inside a vented hood. The polymers are considered
to be nonhazardous materials, but skin contact or inhalation of
vapor/ powder should be avoided.
(
2 ) P olyallylamine and Acetonylacetone. The poly(allyl-
amine) 10 wt % solution was prepared by mixing appropriate
amounts of poly(allylamine) and water. The derivatization reaction
was prepared by adding 1.0 g of acetonylacetone into 5.0 g of poly-
RESULTS AND DISCUSSION
Figure 1 shows the total ion chromatogram (TIC) of the
reaction product of methylamine and acetonylacetone. The reac-
tion equation can be expressed as follows:
(
allylamine) solution and then slowly adding 1.0 g of NaOH 10
wt % solution. The reaction takes place instantly at room temper-
ature. The reacted solution was first frozen and then put on a
freeze-drier (model 75034, Labconco Corp., Kansas City, MO) to
remove the water. The final reaction product, poly(allyl 2,5-
dimethyl pyrrole), is a light yellow-green solid.
(
3 ) Methylamine and Ethylene-Carbon Monoxide Alter-
nating Copolymer or Ethylene-Carbon Monoxide, Styrene-
Carbon Monoxide Alternating Terpolymer. A 0.5-g sample
(
white solid powder) of ethylene-carbon monoxide alternating
copolymer was mixed with 5.0 g of methylamine, 40 wt % aqueous
solution (a clear solution), in a reaction vial. The reaction mixture
was allowed to sit open in a hood at room temperature for 3 days
until all the methylamine aqueous solution evaporated. During
the methylamine evaporation, the color of the solid powder turned
from white to brown. The reaction product was a dark brown solid
powder. The reaction of ethylene-carbon monoxide, styrene-
carbon monoxide alternating terpolymer with methylamine is the
same as ethylene-carbon monoxide alternating copolymer.
P y-GC/ MS Conditions. Samples of polymer were carefully
deposited into a quartz tube. The quartz tube was put into an off-
On the basis of the reaction equation, the major reaction
product should be the 1,2,5-trimethylpyrrole with the assumption
that there is no structural rearrangement during the reaction.
Comparison of the mass spectrum of the major peak (at retention
time 12.18 min) with the NIST mass spectra library finds that there
are several mass spectra from different trimethyl-substituted
pyrrole compounds with more than 95% match. The mass
spectrum of the reaction product is not specific enough to
differentiate from other possible candidates. Theoretically, the
(
(
8) Wang, F. C.-Y. Anal. Chem. 1 9 9 8 , 70, 3642-3648.
9) Kiji, J.; Okano, T.; Chiyoda, T.; Bertini, F.; Audisio, G. J. Anal. Appl. Pyrolysis
1
9 9 7 , 40-41, 331-345.
1132 Analytical Chemistry, Vol. 71, No. 6, March 15, 1999