In this work, the synthesis of zeolites using 1-butyl-3-methylimidazolium chloride [C 4 MI]Cl as a structure-directing agent was investigated. The organic cation shows effectiveness and selectivity for the syntheses of TON zeolites under different reaction conditions compared to the traditional structuredirecting agent, 1,8-diaminooctane. The 1-butyl-3-methylimidazolium cation lead to highly crystalline materials and its role as OSDA in our synthesis conditions has been confirmed by characterization techniques. ICP-OES confirms the presence of Al in the samples and
27Al MAS NMR analysis indicated that aluminum atoms were incorporated in tetrahedral coordination. Scanning electron microscopy indicated that changing the crystallization condition (static or stirring), zeolites with different crystal size were obtained, which consequently affects the textural properties of the zeolites. Moreover, varying some synthesis parameters MFI zeolite can also be obtained.
publicado na web em 10/02/2017Candida antarctica lipase B (CALB) is an enzyme able to catalyze chemical reaction, however when it is used as a free enzyme, it cannot be recovered from reaction medium. One of the alternatives is to immobilize the enzymes on a support which allows the maintenance of their catalytic activities. The purpose of this paper was to immobilize the CALB on MCM-48 using the ionic solid [C 16 MI]Cl as structure director. 2 2 CCRD (Central Composite Rotational Design) was proposed to analyze the influence of the variables like enzyme mass (0.059 to 0.341 g) and ionic solid concentration (0.59 to 3.41%) in the enzyme immobilization process to obtain the maximum esterification activity in order to optimize the process. After immobilization, the study results showed that the enzymes exhibited improvement of thermal (40, 60 and 80 ºC) and storage stability (90 days), besides the possibility to reuse of the enzyme up to 10 times, showing residual activity of 50%.
Neste trabalho foram realizadas a síntese de seis materiais zeolíticos utilizando o sólido iônico cloreto de 1-hexadecil-3-metilmidazólio como agente direcionador de estrutura. O mesmo foi sintetizado utilizando rota clássica de síntese e posteriormente utilizado na síntese dos materiais MCM. Os materias zeolíticos estudados foram do tipo MCM, com ou sem metais acoplados. Primeiramente foram sintetizados os materiais MCM-41 e MCM-48 puros, os quais apresentaram estado cristalino quando analisados por difração de raios X e picos compatíveis com estas estruturas quando comparados com dados descritos na literatura. Logo após foram sintetizadas os materiais Ti-MCM-41, Ti-MCM-48, Zn-MCM-41 e Zn-MCM-48, os quais apresentaram estado cristalino na presença dos metais quando analisados por difração de raios X. Posteriormente as amostras foram utilizadas para testes preliminares de fotocatálise e de adsorção, onde apenas a amostra de Zn-MCM-48 apresentou atividade, adsorvendo o azul do metileno. O fato de que os outros materiais zeolíticos não apresentaram nenhuma atividade de retenção/degradação do corante, foi devido ao fato de que alguns destes materiais apresentarem características hidrofóbicas. Uma vez que os materiais são hidrofóbicos, a reação em meio aquoso não ficou homogênea, com os materiais ficando na interface água/ar, o que pode ter dispersado a luz, invés de ativar o metal para a catálise.
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