Ozonolysis of 1,4-cis-polyisoprene and 1,4-trans-polyisoprene in solution

摘要

The reaction of ozone with 1,4-cis-polyisoprene (E-IR) and 1,4-trans-polyisoprene (Z-IR) has been investigated in CCl_4 solution. By means of IR-spectroscopy and ~1H-NMR spectroscopy it was established that the basic ozonolysis products of both elastomers are ozonides, ketones, and aldehydes. The ozonide:ketone:aldehyde ratio, obtained from NMR spectra, was 40:37:23 and 42:39:19 for E-IR and Z-IR, respectively. In addition to the specified functional groups, epoxide groups were also found, their amount being 8 and 7 for E-IR and Z-IR, respectively, in relation to reacted ozone. Based on differential scanning calorimetry analysis of partially ozonized elastomers, the enthalpy of the ozonide thermal decomposition of the two investigated polyisoprenes was eval- uated. A reaction mechanism is proposed, which explains the formation of all identified functional groups.