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Doctoral Thesis
DOI
10.11606/T.46.2011.tde-05092012-081610
Document
Author
Full name
Valdinéia Cecília da Silva
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2011
Supervisor
Committee
Seoud, Omar Abdel Moneim Abou El (President)
Ando, Rômulo Augusto
Areas, Elizabeth Pinheiro Gomes
Frollini, Elisabete
Ramos, Ludmila de Araújo
Title in Portuguese
Solventes verdes para biopolímeros: síntese e aplicação de líquidos iônicos na derivatização de celulose
Keywords in Portuguese
Derivatização de celulose
Dissolução de celulose
Planejamento experimental
Síntese de líquidos iônicos
Solventes
Abstract in Portuguese
Esta tese tem como objetivo estudar a derivatização da celulose sob condições homogêneas, utilizando líquidos iônicos (LIs), em micro-ondas, através de um método simples e reprodutível. Foram estudadas três etapas: i) Síntese dos LIs, buscando otimizar seu preparo; ii) Efeitos da estrutura dos LIs sobre a dissolução de celulose; iii) Otimização da derivatização da celulose em LIs. Foi realizado um planejamento experimental para a otimização da síntese dos LIs, mostrando-se que o uso de solvente molecular como diluente não traz vantagens. Na dissolução de celuloses fibrosas em LIs, observou-se a importância das estruturas dos cátions e ânions destes. Estudou-se a influência de um solvente molecular, DMSO, na reação de derivatização de celulose em LIs e percebeu-se que o uso do mesmo não é vantajoso. Por fim, realizou-se um planejamento experimental da acetilação da celulose, mostrando-se quais fatores mais afetam esse processo: tempo de reação, razão molar de anidrido acético/celulose e temperatura
Title in English
Green solvents for biopolymers: synthesis of ionic liquids and their use in derivatization of cellulose
Keywords in English
Cellulose homogeneous acylation
Derivatization of cellulose
Dissolution of cellulose
Experimental design
Ionic liquids
Solvents
Synthesis optimization
Abstract in English
The work reported has the target of studying the acylation of cellulose under homogeneous reaction conditions. Imidazolium-based ionic Liquids (ILs) were employed as solvents, and the reaction was assisted by a microwave. These following processes have been studied: Optimization of the synthesis of ILs; ii) Effects of the structure of ILs on the dissolution of cellulose; iii) Optimization of cellulose acylation. Experimental design has been applied in order to optimize the synthesis of ILs. The use of DMSO as a diluent decreased the efficiency of the synthesis. Dissolution of cellulose (eucalyptus, mercerized eucalyptus and mercerized cotton) in several ILs has shown the importance of the counter-ion and the structure of the cation side-chain. The addition of DMSO decreased the amount of dissolved cellulose. Experimental design has been applied in order to optimize the acetylation of cellulose. Reaction time, molar ratio acetic anhydride/anhydroglucose unit, and cellulose concentration influenced the reaction outcome.
 
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Publishing Date
2012-10-24
 
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