Frequency dependence Aniline

Figure 9.23 Frequency dependence of losses due to reflection (SEj ) and absorption (SE ) for MWCNT-loaded PANl nanocomposites having different loadings of MWCNT relative to aniline monomer viz. PCNTO (0.0 wt.%), PCNT5 (5.0 wt.%), PCNTIO (10 wt.%), PCNT20 (20 wt.%), and PCNT25 (25 wt.%). Loss tangent (tan 6) of in-situ synthesized PANl-MWCNT nanocomposites as a function of MWCNT loading. Reprinted from Ref [4] with permission from Elsevier.

Amino groups may act not only as proton acceptor, but also as proton donor. Acidic N—H protons interact with basic solvents. In these cases an ortho-nitro group in an aniline system competes with the solvent by an internal hydrogen bond66, as depicted in 12. The stretching frequencies (by IR spectra in carbon tetrachloride) of vnh of complexes between A-methylaniline or diphenylamine (and some nitro-anilines66) and solvents depend on the proton accepting ability of the solvent (which is a moderate base)67. The frequency shifts are linearly related to the solvent s donor number (DN)3. 

Two-colour photoionization spectroscopy of aniline cooled in a supersonic jet. Strong propensity for vertical (An = 0) ionization allows vibrational frequencies of CgHgNH2 ( B,) to be determined Two-colour photoacoustic and MPI spectra of aniline, determined as a function of time delay between the two laser pulses. Observed both ionization and dissociation t MPI/TOF mass spectrometric study of phenol. Mechanism of ionization and ion fragmentation t MPI/TOF mass spectrometric study of fragmentation patterns in benzaldehyde. Strong wavelength dependence observed at 266 and 355 nm. Results show operation of two different mechanisms at these excitation wavelengths... 

By way of introduction let us note that the depolarized spectrum Ivh(co) calculated in Section 7.5 for independent rotors consists of a superposition of Lorentzian bands all centered at zero frequency. In the simplest case of symmetric top rotors the spectrum consists of a single band with a width [q2D + 6<9] which depends only on the translational self-diffusion coefficient D and on the rotational diffusion coefficient 0. This should be compared and contrasted with the depolarized spectrum Ivh(co) of certain pure liquids (e.g., aniline, nitrobenzene, quinoline, hexafluorobenzene) shown schematically in Fig. 12.1.1. The spectrum appears to be split. This entirely novel fea-... 

The second question addressed during the discussion deals with the calculation of the density of VdW states N(E). The major conclusion of the interpretation of the data reported by E.R. Bernstein is to point out this density of states, as being the primary factor controlling the IVR/VP dynamics. These conclusions are based on the comparison between the behaviours of the aniline-Ar complex and the aniline-CH4 complex. It is clear that, within the framework of the serial IVR/VP model, a proper counting of the VdW modes is essential since it drastically affects N(E) and consequently the predictions of the model. The simplest approach is to remark that, besides the three usual VdW modes (one stretch and two bends) aniline-CH4 complex offers three hindered rotation degrees of freedom. But the proper way to take them into account may be non trivial, due to selection rules imposed by symmetry and spin statistics. Simultaneously the exact values of associated (vibrational) frequencies may depend very much on the relative magnitude of the barrier to internal rotation compared to the free rotation frequency. These factors are expected to reduce the density of states. 

As for the dependence of Ar on the cpX molecule (Fig. 2), Fig. 3 shows the plot of k vs. 0 monomer energy for the series of Ar complexes with several benzenic molecules whose stretch frequency values are available. The unassigned spectrum of the aniline-Ar complex recently reported /7/ is very similar to the present results (Fig. 1). Thus we assign the three vdW bands observed in aniline-Ar at 21, 39 8.5 cm" to the, crj vdW... 

The activity of this catalytic system is very high. Although comparisons between data collected in different laboratories should be made with caution, it appears that [PPN][Rh(CO)4] is the most active homogeneous catalyst ever reported for the reduction of nitrobenzene to aniline. In the paper, only forcing conditions were used, in order to reach the highest turnover frequencies. However, we have observed in model studies that nitroarenes reduction to anilines with this catalyst can occur even at room temperature and atmospheric CO pressure. So the reaction appears to be very versatile and easily tuneable depending on the activities required and the apparatus available. 

Temperature dependent microwave frequency dielectric constant of poly(aniline)-camphor sulfonic acid (PAN-CSA) prepared in CHCI3 and m-cresol. Inset microwave frequency conductivity of PAN-CSA (m-cresol). Data were recorded at 6.5 X 10 . After Reference [482], reproduced with permission. 

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