Conversão de álcoois C1-C2 em hidrocarbonetos catalisada por zeólitas / Conversion of C1-C2 alcohols in hydrocarbons catalyed by zeolites

Metanol (MeOH) e etanol (EtOH) podem ser convertidos em hidrocarbonetos utilizando zeólitas ou sólidos ácidos como catalisadores, sendo uma rota alternativa para a geração de insumos petroquímicos, particularmente eteno e propeno. Nos últimos anos aumentou o interesse por novos catalisadores com propriedades físico-químicas que maximizem a atividade e a seletividade aos produtos de interesse. Neste trabalho foram investigadas as zeólitas ZSM-5 e MCM-22 em sua forma ácida (HZSM-5 e HMCM-22) e a zeólita HITQ-2 obtida por deslaminação da MCM-22. Todas as amostras foram caracterizadas por difratometria de raios X (DRX), espectrometria de fluorescência de raios X (FRX), espectrometria de ressonância magnética nuclear com rotação no ângulo mágico, MAS/RMN de 27Al, fisissorção de N2 e dessorção de NH3 à temperatura programada (TPD de NH3). A comparação do desempenho catalítico dos diferentes catalisadores a 500 °C permitiu observar que tanto a distribuição dos produtos quanto a estabilidade dos catalisadores foram significativamente influenciadas pelo álcool estudado o que está de acordo com as diferenças nos mecanismos de formação de hidrocarbonetos

Conversão do metanol em olefinas catalisada pela zeólita MCM - 22 em sua forma original e desalumizada: Conversion of methanol to olefins catalyzed by zeolite MCM - 22 in its original and dehalogenated form

O processo MTO (methanol to olefins) é uma tecnologia alternativa para a geração de insumos petroquímicos, particularmente eteno e propeno, a partir do metano proveniente do gás natural ou do biogás, por via indireta, tendo o metanol como intermediário. A conversão do metanol em hidrocarbonetos ocorre catalisada por sólidos ácidos, de modo que a busca por catalisadores com propriedades físico-químicas que maximizem a atividade e a seletividade aos produtos de interesse na reação tem aumentado. No presente trabalho foi investigada a zeólita MCM-22 em sua forma ácida (HMCM-22) bem como outras duas formas dessa zeólita obtidas a partir do tratamento da forma ácida com ácido oxálico (HMCM-22(AO)) ou com hexafluorossilicato de amônio (HMCM-22(HF)). Elas foram caracterizadas por DRX, fisissorção de N2 e TPD de NH3. Através da comparação do desempenho catalítico a 500 °C, em isoconversão de 96 ± 4 %, foi observado que a zeólita HMCM-22(AO) apresentou os resultados mais promissores em termos de estabilidade e rendimento em olefinas, particularmente propeno, durante todo o tempo de reação estudado

Geração de mesoporos em zeólitas ZSM-5 e seus efeitos na conversão do etanol em olefinas

Developing mesoporosity in HZSM-5 zeolites is an alternative for improving their catalytic performance on chemical reactions. In this work, alkaline and thermal treatments were used to produce mesoporosity. These treatments increased mesoporous area and volume. They also influenced the acid properties of the samples. Concerning catalytic performance, treatments modified reaction product distribution. Whereas alkaline treatment favored formation of olefins and increased propene ratio in the beginning of the reaction, thermal treatment resulted in formation of only ethylene due to the low acidity of the sample

Efeito da composição das correntes do conversor das unidades de FCC no desempenho catalítico de aditivos DESOx Influence of the composition of the streams to the FCC converter unit on the catalytic performance of DESOx additives

<abstract language="eng">Hydrotalcite-like compounds having Mg partially replaced by Cu or Mn were prepared and used as precursors for two mixed oxides (Cu-OM50 and Mn-OM50) that were evaluated for SOx removal in the presence of O2, NO and CO. Under SO2/O2 reaction system, SOx removal was slightly higher over Cu-OM50. The addition of CO and NO to the feed markedly hindered the SO2 oxidation over Cu-OM50 while no significant effect was observed for Mn-OM50. For the regeneration step, the use of propane instead of H2 reduces regeneration capacity, mainly for Cu-OM50. Mn-OM50 was less affected by the feed composition, suggesting that it was a promising additive for SOx removal

P -73 Pharmaceutical Science Analytical Chemistry STRATEGIES FOR THE VALIDATION OF STEAM STERILIZATION PROCESS IN AUTOCLAVES FROM THE PHARMACEUTICAL INDUSTRY

ABSTRACT The process of sterilization in the asepsis pharmaceutical ensures the materials used in the production of medicines. The method of saturated steam sterilization is always the first choice in the pharmaceutical industry because it is the most effective, faster, with better cost / benefit and with less environmental impact. In order to ensure necessary sterility, the qualification of autoclaves and validation of requirements when their loads are required by national and international regulatory bodies. The regulations of these bodies are not always objective and clear, indicating what should be done without specifying how it should be done. The focus of this work was to create a validation methodology, change control and revalidation in horizontal autoclaves, highlighting the critical points of the process, exploring the theoretical concepts of bioengineering. For this, we used statistical techniques for analyzing data collected in a study of thermal distribution, heat penetration and microbiological challenges to determine a fast, safe and effective that meets the requirements of regulatory bodies without affecting the production capacity of industrial plants and quality of the sterilization process

Influence of basic properties of Mg,Al-mixed oxides on their catalytic activity in knoevenagel condensation between benzaldehyde and phenylsulfonylacetonitrile

The catalytic performance of Mg,Al-mixed oxides (MO20, MO25 and MO33) derived from hydrotalcites was evaluated in the Knoevenagel reaction between benzaldehyde and phenylsulfonylacetonitrile at 373 and 383 K. The best results were obtained for the sample MO20 that presented the highest basic sites density and external area and the smallest crystallite sizes. The relative amount of basic sites with weak to intermediate strength also played an important role on catalytic performance. By increasing the catalyst content from 1 to 5 wt.% at 383 K, a complete conversion of the reactants is attained, producing &#945;-phenylsulfonylcinnamonitrile with a selectivity of 100%

Biosorption of lead by the brown seaweed Sargassum filipendula - batch and continuous pilot studies

The biosorption of lead by the brown alga Sargassum filipendula was studied. pH 4.0 was the optimum value for the biosorption of lead. Isotherms indicated that for solutions containing 0.03 ± 0.001 up to 3.27 ± 0.04 mmol/L of lead, 2.0g/L was the optimum biomass concentration. The Langmuir model was fitted to represent the experimental data, and the kinetics of biosorption presented equilibrium in 30 min. The continuous system operated for 56 hrs presenting a 100% binding of ionic lead, which corresponds to an accumulation of 168 g lead, equivalent to a load of 1.7 mmol ionic lead/g Sargassum filipendula. The results that were obtained in a continuous system showed a gradual saturation of the biomass in the reactors

Batch and fixed-bed column biosorption of manganese ion by Sargassum filipendula

This paper presents experimental data of the biosorption of manganese onto Sargassum filipendula in both batch and fixed-bed column systems. Batch equilibrium data were used for nonlinear fittings of the Langmuir and Freundlich isotherms. A mathematical model based on mass balances in the fluid and in the sorbent was applied to represent the experimental fixed-bed column data. The utilization of isotherm parameters from the batch experiments in the breakthrough model implied a significant mismatch in relation to the laboratory data. Alternatively, additional fixed-bed column data provided new parameters for the isotherm evaluation, and the corresponding simulated profile of the breakthrough curve reached better agreement to the experimental results