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Master's Dissertation
DOI
10.11606/D.46.2012.tde-04092012-161044
Document
Author
Full name
Tiago de Angelis Cordeiro
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2012
Supervisor
Committee
Bazito, Reinaldo Camino (President)
Bastos, Erick Leite
Possidonio, Shirley
Title in Portuguese
Novos tensoativos não-iônicos para CO2-supercrítico: síntese e estudo de algumas propriedades
Keywords in Portuguese
Carboidratos
Fluidos supercríticos
Química verde
Tensoativos
Abstract in Portuguese
O CO2 supercrítico (CO2-sc) é um bom solvente para substâncias apolares e pouco polares de baixa massa molecular. A fim de tornar este meio um melhor solvente para uma gama maior de substâncias, desenvolvemos 8 novos tensoativos, sendo seis derivados de açúcares (N-metil-D-glucamina, 2-D-Glucosamina e Sorbitano) e três derivados de óleos vegetais (linhaça e palma). Os tensoativos possuem como grupos CO2-fílicos, o acetato (peracetilados) ou o t-butil-glicidil-éter, e como grupo CO2-fóbico o dodecanoato, que pode proporcionar um ambiente "apolar" em eventuais agregados formados em CO2-sc. A solubilidade e o comportamento de fase destes novos tensoativos em CO2-sc foram investigados, mostrando-se bastante solúveis e apresentando pontos de névoa comparáveis a outros tensoativos fluorados (mais agressivos, do ponto de vista ambiental). A polaridade que estes tensoativos agregam ao meio foi verificada através de análises de solvatocromismo, utilizando o corante de Reichardt (Betaína-30) e fluorescência de pireno, as quais mostraram resultados bastante promissores, obtendo-se polaridades baixas e médias (similares a álcoois de cadeia média ou solventes clorados).
Title in English
New nonionic surfactants for supercritical CO2: synthesis and study of some properties
Keywords in English
Carbohydrates
Green chemistry
Supercritical fluids
Surfactants
Abstract in English
Supercritical CO2 (sc-CO2) is a good solvent for non-polar or almost non-polar substances with low molecular mass. In order to turn this medium into a better solvent for a wider range of substances, we developed 8 new surfactants, six of them sugar derivatives (N-methyl-D-glucamine, 2-D-Glucosamine and Sorbitan), and three of them vegetable oil derivatives (palm and linseed). The surfactants have either acetate (peracetylated) or t-butyl-glycidyl ether as CO2-philic groups, and as CO2-phobic group, dodecanoate, that can provide an "apolar" environment in aggregates that might be formed in sc-CO2. The solubility and phase behavior of these new surfactants in sc-CO2 were investigated, and they showed to be very soluble presenting low cloud pressures comparable to fluorinated surfactants (that are more aggressive from an environmental perspective). The polarity that these new surfactants brought to the medium was verified through the solvatochromic analysis, using the Reichardt's dye (Betaine-30) and pyrene fluorescence, which showed promising results, with polarities similar to medium chain alcohols or chlorinated solvents
 
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Publishing Date
2012-10-24
 
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