Production of Solketal Using Acid Zeolites as Catalysts

Commercial solketal is known as Augeo™ SL 191 and is produced by Rhodia (a member of the Solvay Group), which stands out as a slow evaporation solvent derived from glycerin which is considered a renewable source. It has low toxicity to human health and the environment. It is a good solvent for resins and polymers, replacing solvents derived from petroleum, and can be used as an additive of (bio) fuels. This work aimed to study acidy zeolites (H-BEA, H-MOR, H-MFI, and H-FER) as new heterogeneous catalysts of solketal production, through the ketalization reaction of glycerol with acetone. The catalytic activity showed H-BEA > H-MOR = H-MFI > H-FER after 180 min, in kinetics study. The major conversion was 85% for H-BEA. It was also verified that all the catalysts can be reused four times without washing or pretreatment among reactions in batch reactor. The solketal produced in this work was characterized by comparing it with its commercial standard, obtaining very similar characteristics

Modification of natural Clinoptilolite zeolite by combined treatment (acid-alkaline)

As zeólitas são matérias com microporos bastante usadas em adsorção e catálise, porém o pequeno tamanho dos poros limita a aplicação quando se trata de adsorção de moléculas grandes. Nesse sentido, torna-se interessante modificar esses materiais naturais visando a novas aplicações, já que as zeólitas naturais apresentam baixo custo. A clinoptilolita natural foi tratada com ácido e posteriormente com base. Os materiais naturais e tratados foram caracterizados por difração de raios X (DRX), análise química por fluorescência de raios X (FRX) e análises de adsorção/dessorção de N2 . Foi realizada uma análise estatística da influência dos parâmetros de tratamento nas propriedades dos materiais. A concentração de NaOH é o parâmetro de tratamento de maior influência nas propriedades dos materiais. Maior concentração de NaOH gera mais quantidade de aluminossilicatos (diminuindo a quantidade de clinoptilolita), aumenta a remoção de silício e, consequentemente, diminui a relação molar Si/Al, porém esse aumento da concentração gera diminuição nas propriedades texturais. Além disso, as regiões microporosas de algumas amostras foram caracterizadas por adsorção de CO2 a 273 K. As condições de 0,1 moL/L de NaOH, 50 °C e tempos menores a 0,5 h foram determinadas para um maior aumento das propriedades texturaisZeolites are micropore materials widely used in adsorption and catalysis, however, the small pore size limits the application for adsorption of large molecules. In this sense, it becomes interesting to modify these natural materials for new applications, since the natural zeolites present low cost. The natural Clinoptilolite was treated with acid and subsequently with base. Natural and treated materials were characterized by X-ray diffraction (XRD), X-ray fluorescence chemical analysis (XRF) and N2 Adsorption/Desorption Analysis. A statistical analysis and the influence of the treatment parameters on the properties of the materials were carried out. The concentration of NaOH is the parameter of greater influence treatment in the properties of the materials. The higher concentration of NaOH gives more aluminosilicates (decreasing the amount of clinoptilolite), increases silicon removal, consequently the Si/ Al molar ratio, but this increase in concentration leads to decrease in textural properties. The microporous region of some samples was characterized by CO2 adsorption at 273 K. The conditions of 0.1 mol/L of NaOH, 50 °C and times shorter than 0.5 h were determined for a greater increase of textural properties.Fil: Castro de Souza, Vanessa. Universidade Federal do Rio Grande do Norte; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Villarroel Rocha, Jhonny. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Araújo, Maria José Gomes de. Universidade Federal do Rio Grande do Norte; BrasilFil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Pergher, Sibele Berenice Castellã. Universidade Federal do Rio Grande do Norte; Brasi

<b>Preparação e caracterização da zeólita MCM-36</b> - DOI: 10.4025/actascitechnol.v25i1.2252

Preparação e caracterização da zeólita MCM-36. A zeólita MCM-36 foi preparada com relação molar inicial de Si/Al de 50, e zeólita MCM-22 com relação molar Si/Al de 50 foi preparada para critérios de comparação. Ambas as zeólitas foram caracterizadas por diversas técnicas: Análises Químicas por Espectroscopia de Absorção Atômica (EAA); Difração de Raios X (DRX); Análises Texturais por Adsorção de N2 e Ar; Microscopia Eletrônica de Varredura (MEV) e Espectrometria no Infravermelho (IV). O material MCM-36 é obtido pela pilarização do precursor da zeólita MCM-22 com silício. Foi observado que o processo de pilarização proporcionou um aumento do espaçamento basal de 27,5 para >45&Aring; e da superfície específica de 430 para 810m2/g. O material MCM-36 é constituído por lâminas, com um sistema de poros de canais sinusoidais de 10MR, separadas por pilares que dão lugar à formação de mesoporos adicionais em uma ampla faixa com cerca de 25&Aring;

Influence of the Brønsted Acidity on the Ring Opening of Decalin for Pt-USY Catalysts

A challenging hot topic faced by the oil refinery industry is the upgrading of low-quality distillate fractions, such as light cycle oil (LCO), in order to meet current quality standards for diesel fuels. An auspicious technological alternative entails the complete saturation of the aromatic structures followed by the selective cleavage of endocyclic carbon-carbon bonds in the formed naphthenic rings (selective ring opening&mdash;SRO). This work reports the influence of Br&oslash;nsted acid sites of platinum-ultra stable Y zeolite (Pt-USY) catalysts in the SRO of decalin as a model naphthenic feed. A maximum combined yield to selective ring opening products (ROP: C10-alkylcycloalkanes + OCD: C10-alkanes) as high as 28.6 wt% was achieved for 1.6Pt-NaUSY-im catalyst. The molar carbon distribution curve of the hydrocracked (C9-) products varied from M-shaped for 1.4Pt-USY-im catalyst, indicating mainly C&ndash;C bond cleavage of the ring opening products with one remaining naphthenic ring via carbocations and the paring reaction, to not M-shaped for the 1.6Pt-NaUSY-im catalyst, where carbon-carbon bond cleavage occurs preferentially through a hydrogenolysis mechanism on metal sites. High (hydro)thermal stability and secondary mesoporosity of the 1.6Pt-NaUSY-im catalysts make this system highly prospective for upgrading low-quality real distillate feeds

Zeolite A synthesis employing a brazilian coal ash as the silicon and aluminum source and its applications in adsorption and pigment formulation

Zeolite A was synthesized using the coal ash from Siderópolis/RS - Brazil. The synthesis was based on a standard IZA synthesis using coal ash as the Si and Al source. XRF analysis showed that the coal ash has a Si/Al ratio of 1.52, which is close to the Si/Al ratio required to produce zeolite A (1.0). The synthesized materials were analyzed by XRD, SEM and N2 adsorption. More crystalline materials were obtained during synthesis when an additional treatment was applied at a temperature of 353 K at the dissolution of NaOH step. The product formed after 4 hours was the most crystalline, but even the product formed after 1 hour proved to be better than that formed using the standard 4 hours IZA synthesis. The zeolites synthesized by this method had an adsorption capacity of 120 mg.g-1 for Ca2+, half the capacity of commercial zeolite A (300 mg.g-1). It was not possible to obtain blue or green pigments using the synthesized zeolite A