Artigo 26 – Vol. 7 N. 1


Preparation of biopolymeric Schiff bases from chitosan and salicylaldehyde and some of its 5- substituted derivatives with higher degrees of substitution

Autores
 Eliene Leandro de Araújo, Tiago Venâncio, Éder Tadeu Gomes Cavalheiro
Recebido em
 04 de Janeiro de 2018
Aceito em
 20 de Fevereiro de 2018
Publicado em
 15 de Março de 2018
DOI
 10.18362/bjta.v7.i1.26
Páginas
Keywords
Biopolymers, Schiff bases, Degree of substitution, Salicylaldehyde derivatives, Chitosan

 

Resumo

In the present work optimized reaction conditions were used to improve the degree of substitution (DS) in biopolymeric Schiff bases prepared chitosan (CTS) and salicylaldehyde (CH) as well as its 5-methoxy (CMO), 5-nitro (CN), 5-methyl (CMe), 5-chloro (CCl) and 5-bromo (CBr) derivatives. The substituted biopolymers were characterized by 1H NMR and FTIR, demonstrating the presence of the desired Schiff bases on the polymeric structure and significant increase in the DS, regarding non-optimized conditions. Thermogravimetric data (TG) revealed that some Schiff bases seem to improve the thermal stability on the substituted domains of the biopolymers increasing the mass loss in the second decomposition step. In addition to the resonance and inductive effects from the ligands, that affects the DS, there also influence from the reaction temperature and time suggesting that thermodynamic and kinetic effects also interfere in the final DS value.
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