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The synthesis of chitosan Schiff bases, N-benzylidene chitosan (CTB), 4-dimethylamino-benzylidene chitosan (CTDB) and 4-nitro-benzylidene chitosan (CTNB), and their interaction with Cu 2? , Zn 2? and Ni 2? were studied. The content of metal ions was determined by atomic absorption spectrometry, and the results showed that chitosan exhibited higher chelating capacity for the metal ions. Morphological changes of Schiff bases and complexes were demonstrated by SEM images. The presence of crystals attributed to copper sulfate adsorbed on the polymers surface was also observed, which indicates that part of the metal content is in the salt adsorbed and might influence in their further application studies. X-ray diffraction patterns showed that the formation of complexes resulted in the decrease in crystallinity. The thermal behavior of derivative and metal complexes were studied by thermogravimetric analysis, differential thermogravimetric analysis and differential scanning calorimetry. The results showed that the presence of new groups and metal ions bonded to chitosan affected their thermal stability.

The present study describes the clean synthesis of non-phosgene organic carbonates (NPOCs) from a selective multicomponent reaction with two important by-products from sugar and alcohol industries, namely, fusel alcohols and carbon dioxide, in the presence of 1,8-diazabicycloundecene (DBU), 1,5-diazabicyclo[4.3.0]-non-5-ene (DBN) or 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]-pyrimidine (TBD) and an alkylating agent. The bases were used for the nucleophilic activation of the alcohols. The synthesis of carbonates was carried out without solvent and confirmed by GC-MS with EI ionization mode, 1 H-and 13 C-NMR and FT-IR analysis. The carbonates were obtained in excellent yields. Crude fusel alcohol can be converted to alkylcarbonates. The proposed methodology can also be employed to convert other hydroxylated compounds into carbonates.