Molecular Sieve
Mostrando 1-12 de 164 artigos, teses e dissertações.
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1. SYNTHESIS, CHARACTERIZATION AND EVALUATION OF THE HETEROGENEOUS BASIC CATALYST DAPTS-MCM-41 IN THE INTERESTERIFICATION REACTION OF PALM OIL AND PALM KERNEL OIL BLENDS
Abstract In recent years, the replacement of homogeneous catalysts by heterogeneous catalysts has been investigated as a sustainable alternative technology to obtain different products. In this context, this study investigated the activity of the heterogeneous catalyst DAPTS-MCM-41, obtained from the reaction between the MCM-41 molecular sieve and an organic
Braz. J. Chem. Eng.. Publicado em: 09/12/2019
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2. Influence of Crystallization and Ageing Time on the Reproducibility of Mesoporous Molecular Sieve SBA-15
ABSTRACT The study aimed to assess how the crystallization and ageing times in SBA-15 synthesis influence the reproducibility and particle size of mesoporous molecular sieves. X-ray diffraction showed that higher crystallization times provide greater reproducibility of mesoporous silica, due to the fact that there is no significant variation in the width and
Matéria (Rio J.). Publicado em: 10/06/2019
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3. Influencia del calcio en la retención de humedad por arcilla
ABSTRACT Bentonite as a raw material is an economical alternative to produce desiccants. The literature indicates that it is a good water adsorbent in relation to the desiccants commonly used in industry (silica gel, molecular sieve). In this sense, it is a valid alternative and an economic option since the clay is a natural compound, which makes it environm
Matéria (Rio J.). Publicado em: 19/07/2018
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4. Influence of Aluminum Addition in the Framework of MCM-41 Mesoporous Molecular Sieve Synthesized by Non-Hydrothermal Method in an Alkali-Free System
Purely siliceous MCM-41 and Al-containing MCM-41 (Al-MCM-41) mesoporous materials were synthesized by non-hydrothermal method in alkali-free ions medium at room temperature and short reaction times. Under these synthesis conditions, it was also investigated the influence of Al incorporation in the crystal structure of MCM-41. The solids were characterized by
Mat. Res.. Publicado em: 17/08/2017
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5. Immobilization of lipase on mesoporous molecular sieve MCM-48 obtained using ionic solid as a structure director and esterification reaction on solvent-free
Candida 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
Quím. Nova. Publicado em: 2017-04
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6. CERIUM INCORPORATED INTO A MESOPOROUS MOLECULAR SIEVE (MCM-41)
Abstract The synthesis and characterization of a mesoporous molecular sieve (MCM-41) was studied due to its high surface area and large pore volume and to target potential applications in adsorption and catalysis. Rare earth elements have special chemical properties and are efficient promoters for supports. In this study, a mesoporous molecular sieve that in
Braz. J. Chem. Eng.. Publicado em: 2016-09
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7. Comparison of Kinetic Study of CTMA+ Removal of Molecular Sieve Ti-MCM-41 Synthesized with Natural and Commercial Silica
This work aimed to determine and compare the apparent activation energy, involved in thermal decomposition of CTMA+ from the pores of Ti-MCM-41 synthesized by two different source of silica in order to evaluate their influence in the template removal. The molecular sieves Ti-MCM-41 were synthesized using rice husk ash (RHA), as alternative low cost source of
Mat. Res.. Publicado em: 2015-06
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8. Kinetic study of the catalytic pyrolysis of elephant grass using Ti-MCM-41
This work aimed to study the kinetics of thermal and catalytic pyrolysis using Ti-MCM-41 as catalyst in order to assess the catalytic pyrolysis efficiency compared to thermal pyrolysis of elephant grass. Ti-MCM-41 molecular sieve was synthesized by hydrothermal method from hydrogel with the following molar composition:1.00 CTMABr: 4.00 SiO2:X TiO2: 1 + X Na2
Mat. Res.. Publicado em: 05/08/2014
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9. Synthesis and characterizaton of molecular sieve SAPO-34 for the production of light olefins from methanol / Síntese e caracterização da peneira molecular SAPO-34 para reação de obtenção de olefinas leves a partir de metanol
A peneira molecular SAPO-34 foi sintetizada pelo método de cristalização hidrotérmica com razões molares de SiO IND. 2/Al IND. 2 O IND. 3 (SAR) de 0,3, 0,5 e 0,7. As amostras foram secas e calcinadas para serem utilizadas na reação catalítica de conversão de metanol para olefinas leves (eteno e propeno). Os sólidos foram caracterizados e foi observ
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 15/12/2011
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10. Síntese e impregnação de peneiras moleculares Fe MCM-41 derivada de sílica da casca do arroz
As peneiras moleculares mesoporosas do tipo MCM-41 e FeMCM-41, são consideradas promissoras como suporte para metais, usadas como catalisadores em processos de refino de materiais a base de petróleo e como adsorventes com o propósito de proteção ambiental. Neste trabalho MCM-41 e FeMCM-41 foram sintetizadas utilizando a cinza da casca de arroz CCA, como
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/11/2011
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11. Mesoporous molecular sieve MCM-41 synthesis from fluoride media
A study of the synthesis of MCM-41 mesoporous molecular sieves in fluoride media, having no alkaline metal ions, was performed by changing the gel composition and crystallization temperature and time. X-ray diffraction and nitrogen adsorption analyses showed that highly ordered MCM-41 samples were obtained from gels with a NH4OH/SiO2 molar ratio in the 3.25-
Brazilian Journal of Chemical Engineering. Publicado em: 2011-12
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12. Guazuma ulmifolia (Sterculiaceae), a new natural host of 16SrXV phytoplasma in Costa Rica
Guacimo trees (Guazuma ulmifolia, Sterculiaceae) showing witches' broom symptoms (GWB), small leaves, short internodes, stunting and no flower and fruit production were observed on side roads and fences in different areas of Costa Rica. The occurrence of phytoplasma infection in GWB trees was evaluated by transmission electron microscopy (TEM), and by molecu
Tropical Plant Pathology. Publicado em: 2011-04