Synthesis of novel polymer-bound morpholine-N-oxides as possible oxidants in alkene oxidation

[摘要] English: In this dissertation is reported the syntheses and characterisation of polysuccinimide- andpolyepichlorohydrin-bound morpholine-N-oxide as possible polymeric oxidants. The use of1H NMR spectroscopy to determine polymer chain length and degree of fuctionalisation isdescribed in detail. The synthesised polymers were used as potential oxidants in catalyticoxidation of alkenes. However, none of the preliminary trials on the epoxidation anddihydroxylation of trans-stilbene were successful. Two metal-containing phthalocyanines; one coordinated to Mn(III), the other to Zn(II), weresynthesized by metal insertion into the metal-free non-peripheral octa substitutedphthalocyanine (2HPc-(C13H27)8). The initial complex, 2HPc-(C13H27)8, was synthesized bytetramerization of 3,6-tridecylphthalonitrile, which was prepared by a three-step synthesisfrom thiophene. Characterization of the phthalocyanines included electrochemical and thermalanalysis. The cyclic voltammograms of the 2H and Zn phthalocyanines showed two ringbasedoxidations (0.116 V; 0.487 V and 0.044 V; 0.558V respectively) as well as two ringbasedreductions (-1.791 V; -1.456 V and -2.054 V; -1.663 V respectively), vs Fc/Fc+ at 100mV/s. The Mn derivative showed two ring-based oxidations (0.373 V and 0.864 V) while onlyone ring-based reduction was observed (-1.732 V). The Mn(II) oxidation was observed at0.641 V while Mn(III) reductions was observed at -0.742 V and -0.660 V (for Cl- and CH3Oaxialligands) giving largeEp values of 1.566 V and 1.484 V.The newly synthesized tridecyl-substituted metal-free and zinc phthalocyanines exhibitedliquid crystalline mesophase behavior when subjected to differential scanning calorimetricstudies of between 40 oC �?120 oC and 40 oC �?280 oC respectively, giving mesophasetemperature ranges of 12.4 oC and 83.0 oC respectively. The manganese phthalocyanine,xiihowever, did not show any liquid crystal behavior. The manganese tridecyl-substitutedphthalocyanine was used as catalyst in the molecular oxygen based epoxidation of transstilbeneand gave low yields of the desired epoxide, trans-stilbene oxide. Epoxidation oftrans-stilbene using N-methylmorpholine-N-oxide as oxidant and Mn(III)salen as co-catalystgave trans-stilbene oxide in moderate yields.

[发布机构] University of the Free State