Investigation of a molybdenum-containing silica catalyst synthesized by the sol–gel process in heterogeneous catalytic esterification reactions using methanol and ethanol

Bail, Alesandro; Santos, Vannia Cristina dos; Freitas, Marianne Roque de; Ramos, Luiz Pereira; Schreiner, W. H.; Ricci, Gustavo Pimenta; Ciuffi, Kátia J.; Nakagaki, Shirley

doi:10.1016/j.apcatb.2012.11.009

Cited by 41 publications

(18 citation statements)

References 58 publications

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“…The N 2 isotherms of Mo5-SiO 2 , Mo10-SiO 2 and Mo12-SiO 2 samples displayed type H1 hysteresis loop which is characteristic of mesoporous materials having the pores with uniform shape and size [24]. The same type of hysteresis loop was reported for Mo-SiO 2 solids synthetized by sol-gel method by Bail et al [26]. characteristic of the solids having slit shaped pores with nonuniform size and/or shape [24].…”

Section: Textural Propertiessupporting

confidence: 57%

Dehydrogenation of methylcyclohexane to toluene over partially reduced Mo–SiO2 catalysts

Boufaden

Akkari

Pawelec

et al. 2015

Applied Catalysis A: General

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Section: Textural Propertiessupporting

confidence: 57%

Dehydrogenation of methylcyclohexane to toluene over partially reduced Mo–SiO2 catalysts

Boufaden

Akkari

Pawelec

et al. 2015

Applied Catalysis A: General

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“…10. The isotherms of all catalysts are type IV of the International Union of Pure and Applied Chemistry (IUPAC) classification with an H3-type hysteresis loop, indicating that the samples were mesoporous [28,29]. In comparison with ref1 and mod1, the H3 hysteresis loop is formed at relatively lower p/p 0 relative pressures for ref2 and mod2, confirming that these catalysts have a narrower pore size distribution.…”

Section: Catalytic Activity Measurementsupporting

confidence: 61%

Effect of synthesis method on physicochemical and catalytic properties of Cu–Zn-based mesoporous nanocatalysts for water-gas shift reaction

Salehirad

Latifi

2016

Res Chem Intermed

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Two new mesoporous nanocatalysts based on CuO-ZnO/MgO were synthesized by using a modified liquid-phase method. Due to use of this method, the nanocatalysts contained an efficient ZnO/MgO phase in which MgO is incorporated into ZnO phase. The structural and catalytic properties of the nanocatalysts in the water-gas shift reaction were investigated compared with samples prepared by conventional sol-gel and liquid-phase methods as references, as well as a commercial catalyst. The results reveal that the new nanocatalysts exhibited higher surface area, lower degree of agglomeration, and higher activity than the reference samples, indicating the influence of both the synthesis method and phase composition.

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“…Molybdenum compounds are characterized by a remarkable versatility as catalysts, a fact that is related to the ability of this metal to be present on the solid surface in different oxidation states, ranging from Mo 6+ to metallic Mo (Mo 0 ) [21]. Anhydrous sodium molybdate [22], bulk MoO 3 [23], and molybdenum supported on alumina [24], silica, silica-alumina, and titania [25,26], as well as carbon [27] have been used as esterification and transesterification catalysts for biodiesel production from several oils, including waste oil.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Performance of Bulk and Al2O3-Supported Molybdenum Oxide for the Production of Biodiesel from Oil with High Free Fatty Acids Content

et al. 2020

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Non-edible vegetable oils are characterized by high contents of free fatty acids (FFAs) that prevent from using the conventional basic catalysts for the production of biodiesel. In this work, solid acid catalysts are used for the simultaneous esterification and transesterification with methanol of the FFAs and triglycerides contained in sunflower oil acidified with oleic acid. Molybdenum oxide (MoO 3 ), which has been seldom considered as a catalyst for the production of biodiesel, was used in bulk and alumina-supported forms. Results showed that bulk MoO 3 is very active for both transesterification and esterification reactions, but it suffered from severe molybdenum leaching in the reaction medium. When supported on Al 2 O 3 , the MoO 3 performance improved in terms of active phase utilization and stability though molybdenum leaching remained significant. The improvement of catalytic performance was ascribed to the establishment of MoO 3 -Al 2 O 3 interactions that favored the anchorage of molybdenum to the support and the formation of new strong acidic centers, although this effect was offset by a decrease of specific surface area. It is concluded that the development of stable catalysts based on MoO 3 offers an attractive route for the valorization of oils with high FFAs content.Catalysts 2020, 10, 158 2 of 14 of this strategy is obtaining a more sustainable alternative fuel that contributes to reducing the CO 2 emissions to the atmosphere and the dependency of the energy system on petroleum. On the other hand, the basic catalysts usually used in the biodiesel industry (KOH, NaOH, and potassium and sodium methoxides) have important drawbacks [4]. Although they could be replaced by heterogeneous solid catalysts to make their re-utilization possible, some issues concerning those materials such as the lack of the required chemical stability are still not well solved [5][6][7]. Moreover, basic catalysts are not capable of suitably processing virgin, non-edible or waste feedstocks, which are characterized by being relatively rich in free fatty acids (FFAs), because they result deactivated and/or consumed, e.g., by the formation of soaps that also complicate the separation of the products due to their emulsifying properties. In these cases, acid catalysts can be used to perform a pre-esterification of the FFAs followed by base-catalyzed transesterification giving rise to the so-called integrated process for biodiesel production from high FFAs-containing triglyceride feedstocks [1,8]. Nevertheless, this is a multistep process that introduces complexity, thus reducing the competitive advantage of using low-cost feedstocks. It would be more convenient to perform the simultaneous transformation of the triglycerides and FFAs into FAMEs, which can be in fact accomplished using heterogeneous acid catalysts [9][10][11].Heterogeneous acid catalysts considered for biodiesel production comprise a large variety of materials [8][9][10][11][12][13][14][15][16][17][18]. The most representative ones consist on sulfated and tungsta...

show abstract

Investigation of a molybdenum-containing silica catalyst synthesized by the sol–gel process in heterogeneous catalytic esterification reactions using methanol and ethanol

Cited by 41 publications

References 58 publications

Dehydrogenation of methylcyclohexane to toluene over partially reduced Mo–SiO2 catalysts

Dehydrogenation of methylcyclohexane to toluene over partially reduced Mo–SiO2 catalysts

Effect of synthesis method on physicochemical and catalytic properties of Cu–Zn-based mesoporous nanocatalysts for water-gas shift reaction

Catalytic Performance of Bulk and Al2O3-Supported Molybdenum Oxide for the Production of Biodiesel from Oil with High Free Fatty Acids Content

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