A comparative study on porous solid acid oxides as catalysts in the esterification of glycerol with acetic acid

Neto, Antônio Chaves Assis; Oliveira, Alcinéia C.; Rodríguez‐Castellón, Enrique; Campos, Adriana; Freire, Paulo; Sousa, Francisco F.F.; Filho, J. Mendes; Araújo, Júlio; Lang, Rossano

doi:10.1016/j.cattod.2018.05.057

Cited by 23 publications

(14 citation statements)

References 35 publications

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“…The reaction temperature was kept at 120 °C using a nest shape electrical heating jacket with temperature control, whereas the temperature sensor is immersed in the reaction medium. The catalytic tests were carried out in conditions selected from the literature [42] using 500 mg of catalyst (15 wt%, glycerin basis), HAc/ Glyc = 9 molar ratio. After the reaction, the catalyst was removed by filtration and the liquid effluent was analyzed by GC using a Varian CP 3800 chromatograph equipped with a flame ionization detector.…”

Section: Glycerin Acetylation Catalytic Testsmentioning

confidence: 99%

Biodiesel Glycerin Valorization into Oxygenated Fuel Additives

et al. 2021

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Current industrial methods of biodiesel production lead to an excess of crude glycerin which requires costly purification before commercialization. Production of oxygenated fuel additives is a potential route for glycerin valorization. Glycerin acetylation was carried out over heterogeneous acid catalysts (15%, glycerol weight basis) using glacial acetic acid (molar ratio = 9). The catalysts, containing different amounts of phosphate species (P/Si from 10 to 20 atomic ratio), were prepared by wet impregnation of commercial silica with aqueous solutions of diammonium phosphate and ortho-phosphoric acid. X-ray diffraction patterns of calcined solids presented amorphous patterns like raw silica. The prepared catalysts presented, at 120 °C, glycerol conversion higher than 89.5% after 1 h of reaction, been diacetin the major product, with triacetin selectivities lower than 26.1%. Diacetin selectivity was found to be almost invariant with catalyst acidity thus underlining the relevance of catalyst porosity due to the large acetins molecules sizes. The slow rate of triacetin diffusion in narrow pores of catalyst might be responsible for the relatively low yield obtained. Surface phosphate species showed a slow rate of leaching in the reaction medium showing high catalyst stability.

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Section: Glycerin Acetylation Catalytic Testsmentioning

confidence: 99%

Biodiesel Glycerin Valorization into Oxygenated Fuel Additives

et al. 2021

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“…In recent decades, glycerol valorization has received prominent research interest because of escalating biodiesel production [1][2][3]. The large amounts of crude glycerol as the main by-product of the biodiesel industries have impelled the scientific community to look for alternatives to convert the trialcohol into value-added chemicals [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Basic Promoters on Porous Supported Alumina Catalysts for Acetins Production

et al. 2022

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A facile strategy for the design of porous supports was obtained by modifying the sol-gel method followed by the wet impregnation technique. In this respect, herein, the acidity of the γ-Al2O3 phase was modulated by adding basic MgO, La2O3 or ZnO promoters to form binary supported catalysts. The Ni and Co dispersion on the supports associated with their tunable acidity and morphologies resulted in highly porous supported alumina-based catalysts. The physicochemical properties of the solids were comprehensively investigated by XRD, textural properties, Raman and FTIR spectroscopy, SEM-EDS, TEM, EPR and XPS analyses. The catalytic performances in the esterification of glycerol in the presence of acetic acid (EG) for the acetins production were evaluated. The highly dispersed NiO and Co3O4 active species on binary porous supports produced synergistic effects appearing to be the reason for the activity of the solids in the EG reaction. Under the optimized reaction conditions, NiCo/MgO-Al2O3 was found to be a robust solid with superior catalytic performance and improved stability in four reaction cycles with 65.0% of glycerol conversion with an exclusive selectivity of 53% for triacetin. The presence of Co2+/Co3+ and Ni2+ strongly interacting with the spinel γ-Al2O3 and MgAl2O4 phases, the latter having a large number of lattice oxygen species, was considered another active component besides those of Ni and Co in the esterification of glycerol.

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“…A large amount (10 wt %) of by-product glycerol is produced during the production of biodiesel. − Based on sustainable utilization of resources, it is necessary to convert glycerol into high-added-value products like acetoglycerides (monoacetin, diacetin, and triacetin), which are widely used as food additives, fuel additives, cryogenic agents, and biodegradable polyesters. ,− However, monoacetin, as a value-added glycerol derivative, has been studied by researchers due to its high price and wide applications in explosives and tanning agents . Acetic acid has been used as an acylation reagent that reacts with glycerol to form acetoglycerides.…”

Section: Introductionmentioning

confidence: 99%

“…3− ) to enhance the basicity of the catalyst. Thus, PO 4 3− interacts in an in situ manner with water to form protons to activate acetonitrile and Cu 2+ species, which can further effectively activate acetamide. In addition, CO 2 interacts with high-temperature liquid water to further enhance the acidic strength of the reaction system.…”

Section: Introductionmentioning

confidence: 99%

Novel Green Method for the Synthesis of Monoacetin over Bifunctional Cu–Cr Phosphates under the CO₂ Atmosphere

Luo

Chen

Liu

et al. 2020

ACS Appl. Mater. Interfaces

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Monoacetin was synthesized using a novel green method in which acetonitrile was hydrolyzed and then esterified with glycerol over Cu–Cr phosphates under the CO2 atmosphere. Monoacetin was synthesized with high yield (87.6% glycerol conversion and 86.3% monoacetin selectivity) through this one-pot cascade method. In this process, acetonitrile can react with water to form acetamide and further undergo esterification with glycerol. There are two main reasons for obtaining monoacetin in high yield: (1) the interaction of CO2 with high-temperature liquid water enhances the acid strength of the reaction system and then promotes the activation of acetonitrile; and (2) the introduction of Cr species causes a synergistic effect between Cu and Cr species to adjust the acidity and basicity of the catalyst. The introduction of Cr species converts eight-coordinated Cu2+ into four-coordinated Cu2+ to improve the acidity of the catalyst. The introduction of Cr species also causes the surface oxygen to be transformed into lattice oxygen to enhance the basicity of the catalyst. These bimetallic phosphate materials may provide a new pathway for the application of acid–base bifunctional catalytic reactions.

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A comparative study on porous solid acid oxides as catalysts in the esterification of glycerol with acetic acid

Cited by 23 publications

References 35 publications

Biodiesel Glycerin Valorization into Oxygenated Fuel Additives

Biodiesel Glycerin Valorization into Oxygenated Fuel Additives

Effect of Basic Promoters on Porous Supported Alumina Catalysts for Acetins Production

Novel Green Method for the Synthesis of Monoacetin over Bifunctional Cu–Cr Phosphates under the CO₂ Atmosphere

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A comparative study on porous solid acid oxides as catalysts in the esterification of glycerol with acetic acid

Cited by 23 publications

References 35 publications

Biodiesel Glycerin Valorization into Oxygenated Fuel Additives

Biodiesel Glycerin Valorization into Oxygenated Fuel Additives

Effect of Basic Promoters on Porous Supported Alumina Catalysts for Acetins Production

Novel Green Method for the Synthesis of Monoacetin over Bifunctional Cu–Cr Phosphates under the CO2 Atmosphere

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Novel Green Method for the Synthesis of Monoacetin over Bifunctional Cu–Cr Phosphates under the CO₂ Atmosphere