• N S Pandya

      Articles written in Proceedings – Section A

    • The raman spectra of organic compounds: Aniline

      C S Venkateswaran N S Pandya

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      An intense Raman spectrum of aniline has yielded thirty-nine lines. They are: 234 (4,.71), 280 (0, D), 330 (0, D), 387 (4, 63), 408(1), 532 (5,.62), 619 (5,.62), 700(1,), 757 (3,.71), 775(0), 810 (8,.28), 830 (8,.30), 888 (0, P), 938 (1,P), 987 (0 ), 996 (10,.26), 1029 (5,.28), 1060 (0, ), 1110 (0 ), 1149 (3, .78), 1168 (2, .55), 1200(0, P), 1230 (0, P), 1272(4,.33), 1340 (1, D), 1388 (1, D), 1456 (2,.62), 1499 (2, P), 1538 (2, P), 1590 (2, D), 1601 (10,.69), 1612 (2, P), 2922 (2, P), 3020 (0, D), 3046 (10,.53), 3066 (4, P), 3190 (1, D), 3362 (3, P), and 3423 (2, D). Thirty of these are assigned to the benzene ring by comparing these frequencies with those of benzene and its monosubstituted derivatives. 3362 (3 P), 3423 (3 D,) and 1538 (2 P) are assigned to the NH2 group and 830 (8, .30) and 408 (1) to the C–N linkage.

    • The raman spectra of organic compounds: Diethyl disulphide

      C S Venkateswaran N S Pandya

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      An intense Raman spectrum of diethyl disulphide and its polarisation characters are recorded. The spectrum consists of twenty-seven lines. Nine of these are observed for the first time. It is shown that nine of these lines (three of which are depolarised) belong to the ethyl group (C2 H5), and the remaining eighteen of which six are depolarised belong to the chain C2-S-S-C2. The results are discussed in relation to the problem of ‘free rotation’ about the S-S bond. It is concluded that six polarised lines are due to thetrans and twelve due to thecis forms; and that these two types of molecules co-exist in the liquid in equal proportions.

    • The raman spectra of organic compounds: Binary liquid mixtures

      C S Venkateswaran N S Pandya

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      The Raman spectra of two critical solution mixtures, namely cyclo-hexane-aniline and iso-butyric acid-water, are obtained and compared with the spectra of the component liquids. No changes are observed in the cyclohexane-aniline mixture. In the iso-butyric acid-water mixture the following changes are observed: Three fairly intense lines at 510, 1430 and 1654 cm.-1 of the acid disappear in the mixture and instead, broad lines appear at 519 and 1715. The strongest line of the acid at 800 cm.-1 becomes slightly broader and less intense. The strong water band at 3460 appears to be shifted to a slightly higher frequency. From a comparison of these changes with those reported for formic, acetic and trichloroacetic acids, it is concluded that at the critical temperature, the acid molecules change over from dimer to monomer state. This indicates that at or above the critical temperature, the two liquids in the mixture become homogeneous as in solutions. The results are discussed in relation to the cluster formation in the binary liquid mixtures.

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