Transcript Synthetic Routes to Porous Polymers Containing Borazine and Diazaborole Building Blocks Hani M.

Synthetic Routes to Porous Polymers Containing Borazine and Diazaborole
Building Blocks
Hani M. El-Kaderi, Department of Chemistry, Virginia Commonwealth University, Richmond, VA
Borazine building blocks
and a typical topology
-1
3
Nitrogen sorption experiments
B
B
N
O
O
N
N
were performed to investigate
B
B
the
polymers’
permanent
B
B
B
B
N
N
O
N
B
porosity following an activation
process.
All boroxine
polymers B-derived borazine N-derived borazine
exhibited isotherms related to
polymers
of
microporous
nature, which is consistent with
their theoretical computergenerated models.
The
synthesized polymers yielded
BET surface areas between
503 and 1364 m2g-1. Surface
areas of that magnitude are
attractive for a wide range of
applications
including
gas
storage and catalysis.
We also investigated the potential use of these polymers in gas
storage capabilities by performing sorption experiments on gases
such as hydrogen, carbon dioxide, and methane. These isotherms
served to not only indicate uptake at certain temperature and
pressure but also allowed us to calculate the isosteric heat of
adsorption, Qst, an important property in gas storage. Although these
values were lower than what is required to reach the goals for use at
ambient temperature and pressure, in several cases, they
surpassed that of most studied gas storage media to date. These
results along with the gas storage uptakes illustrated these
polymers’ promising capabilities as media for gas storage as well as
gas separation in processes such as carbon dioxide capture and
sequestration.
N2 Uptake (cm g ) STP
A library of porous polymers was successfully synthesized through
the reactions of various aryl amines with boron sources (borane or
boron trihalide, for example) by thermolysis reactions and/or under
catalytic conditions. These polymers resulted in the formation of
borazine rings—the first time that borazine has been incorporated in
a polymeric form. Of the many attractive features of these polymers
is their tunable chemical nature which can be accessed by careful
selection of the building blocks. The simple choice of the aryl amine
and boron source determines the resulting topology and gives rise to
varying spatial, textural, and storage properties. In addition, postsynthesis modification could take advantage of the reactive boronhalide bonds to yield yet more polymers in this library.
700
N2 at 77 K
650
600
550
500
450
400
350
300
250
200
150
100
50
0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
BLP-1_Cl
BLP-2_Cl
BLP-10_Cl
0.8 0.9 1.0
P/Po
Nitrogen isotherms of selected polymers