Phenylene carbonate derivative

Carbon nanotubes have limited solubility in most organic solvents. Phenylene-ethynylene derivatives have been prepared and used to noncovalently functionalize and solubilize these materials by means of the electron donor/electron acceptor characteristics of the polymer backbone. 

As mentioned before, the incorporation of carbon nanotubes in conjugated polymers can lead to improved properties of such composites, one of them being great enhancement of the transport characteristics, which is of primary importance in organic light-emitting diodes (OLEDs) for example. Due to their solubility, which allows easy preparation, composites based on PPV (poly(phenylene vinylene)) derivatives have been extensively studied. Detailed investigation of PmPV (poly(m-phenylene... 

Poly(m-phenylene isophthalamide) derived carbon fibers can be activated by carbon vapor deposition of benzene. The activated carbon fibers are suitable as molecular sieves for air separation. Carbon fibers can be obtained from the aramid by pyrolysis at 750-850°C. The pyrolysis may take place in Ar or CO2. 

The smallest possible five-membered aromatic cyclic carbonate is a derivative of catechol benzo-l,3-dioxolan-2-one (o-phenylene carbonate) (1, Scheme 13). It was synthesized using three different methods the reaction of catechol with phosgene (or its dimer or trimer), ° the reaction of catechol with chloroformate, ° or by transesterification of catechol with diphenyl carbonate. ... 

The name phenylene o-, m-, or p-) is retained for the radical —C5H4—. Bivalent radicals formed from substituted benzene derivatives and having the free valences at ring atoms are named as substituted phenylene radicals, with the carbon atoms having the free valences being numbered 1,2-, 1,3-, or 1,4-, as appropriate. 

Figure 13 shows the irreversible conversion of a nonconjugated poly (p-phenylene pentadienylene) to a lithiun-doped conjugated derivative which has a semiconducting level of conductivity (0.1 to 1.0 S/cm) (29). Obviously, the neutral conjugated derivative of poly (p-phenylene pentadienylene) can then be reversibly generated from the n-type doped material by electrochemical undoping or by p-type compensation. A very similar synthetic method for the conversion of poly(acetylene-co-1,3-butadiene) to polyacetylene has been reported (30), Figure 14. This synthesis of polyacetylene from a nonconjugated precursor polymer containing isolated CH2 units in an otherwise conjugated chain is to be contrasted with the early approach of Marvel et al (6) in which an all-sp3 carbon chain was employed.

These derivatives are soluble in an acetone/water mixture with their p i values similar to that of PIDAA. The phenylene analogs are similar to EDTA except that the two nitrogens are bridged by aromatic rings. These derivatives are soluble in acetone/water. They were characterized by measuring their H- and C-nuclear magnetic resonance (NMR) spectra and Fourier transform infrared (FTTR) spectra. All the PIDAA derivatives showed a peak near 53 ppm for the methylene carbons in carbon NMR spectra. The methylene carbon resonance appears around 44 ppm in the NPG derivative. Thus offers an easier way to characterize these materials. The FTNMR data are listed in Table 1 below. 

M. Dubois, A. Naji,J.P. Buisson, B. Humbert, E. Grivei, and D. Billaud, Characterisation of carbonaceous materials derived from polypara-phenylene pyrolyzed at low temperature, Carbon, 38(9) 1411-1417, 2000. 

Story, B. J., and Koros, W. J. (1991). Sorption of carbon dioxide/methane mixtures in poly(phenylene oxide) and a carboxylated derivative, J. Appl. Polym Sci. 42, 2613. 

Many porous organic polymers are derived from the stationary phase used to pack GC columns. Tenax is one such example. This is a macroporous polymer obtained from diphenyl p-phenylene oxide (DPPO). Generally, this polymer is hydrophobic and does not retain water. However, it exhibits some ability to adsorb polar compounds. As a result of its low surface area (30 m /g), its adsorption capacity is limited and very volatile compounds are not trapped. Therefore, it is an appropriate material for trapping heavier compounds with more than four carbon atoms. Co-precipitated graphitized carbon black and Tenax (in the proportion 23 % to 77 %) was introduced on the market as Tenax GR. This adsorbent combines the advantages of both materials and is approximately twice as effective as Tenax TA [50]. 

Monomers Not Polymerizable by Plasma Initiation. When styrene and a-methy1styrene were subjected to plasma treatment, the monomers became yellowish and only trace amounts of insoluble films were formed. The discoloration was intensified and extensive formation of dark films were observed if carbon tetrachloride was added as the solvent. No post-polymerization was detectable for these monomers. Generally styrene and a-methylstyrene readily undergo thermal polymerization. However, no thermal polymerization was possible for these monomers after having been subjected to plasma treatment for one minute or less. It has been demonstrated from the emission spectra of glow discharge plasma of benzene (6) and its derivatives (7 ) that most of the reaction intermediates are phenyl or benzyl radicals which subsequently form a variety of compounds such as acetylene, methylacetylene, allene, fulvene, biphenyl, poly(p-phenylenes) and so forth. It is possible that styrene and a-methylstyrene also behave similarly, so that species from the monomer plasma are poor initiators for polymerization. 

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