Benzene polyepichlorohydrin

Carbon-13 NMR Analysis of Polyepichlorohydrin. Natural-abundance carbon-13 NMR spectra at 22.6 MHz were measured in benzene at 70°C. with proton noise decoupling, using a Bruker HFX-10 spectrometer equipped with a Nicolet 1085 Fourier transform spectroscopy accessory. 

Figure 8 shows the carbon-13 NMR spectra of crystalline polyepichlorohydrin and the poly(propylene oxide) it yielded by dechlorination with LAH. The poly(propylene oxide) was also highly crystalline (m.p. 64 C. by DTA) and its carbon-13 NMR spectrum corresponds closely to that reported for the isotactic polymer. Thus, the single methylene peak at about 70.2 ppm. in the spectrum of crystalline polyepichlorohydrin is due to isotactic dyads. The poor resolution in this spectrum is due to low solubility of the crystalline polymer in the benzene solvent. No trace of the peaks due to polyepichlorohydrin are observable in the spectra of the poly(propylene oxide) obtained by dechlorination. In addition, the number of observable peaks does not increase as a result of the LAH treatment. This is further evidence that the dechlorination reaction results in smooth replacement of Cl with H without otherwise altering the structure of the polymer. 

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