An unexpected behavior of H3PMo12O40heteropolyacid catalyst on the biphasic hydrolysis of vegetable oils

Silva, M. J. Da; Teixeira, Milena Galdino

doi:10.1039/c6ra27287h

Cited by 26 publications

(10 citation statements)

References 39 publications

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“…Increasing reaction time is negative to biocrude yield of non‐catalytic HTL, demonstrating that longer reaction time enhances the repolymerization or gasification of the intermediates. The HPA‐4 is advantageous to the depolymerization and hydrolysis of lipids to form carboxylic acids, such as oleic acid, and octadecanoic acid, leading to a continuous increase of biocrude yield with the increase of reaction time, initially [42,43] . However, these carboxylic acids are hydrolyzed and oxidized into smaller carboxylic acids molecules, water soluble organics, and gaseous products with increase of reaction time, correspondingly resulting in a dramatical decrease of biocrude yield [44] .…”

Section: Resultsmentioning

confidence: 99%

“…The HPA-4 is advantageous to the depolymerization and hydrolysis of lipids to form carboxylic acids, such as oleic acid, and octadecanoic acid, leading to a continuous increase of biocrude yield with the increase of reaction time, initially. [42,43] However, these carboxylic acids are hydrolyzed and oxidized into smaller carboxylic acids molecules, water soluble organics, and gaseous products with increase of reaction time, correspondingly resulting in a dramatical decrease of biocrude yield. [44] Furthermore, the repolymerization or condensation of chemical intermediates, beneficial to residue production, are the dominate thermochemical reactions of intermediates once the depolymerization and hydrolysis are finished, attributing to the decrease of biocrude yield when the reaction time is longer than 2 h.…”

Section: Effect Of Reaction Time On Hpas-catalyzed Htlmentioning

confidence: 99%

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Keggin‐type Heteropolyacids‐Catalyzed Selective Hydrothermal Oxidation of Microalgae for Low Nitrogen Biofuel Production

Shen

Long

et al. 2020

ChemSusChem

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Hydrothermal liquefaction (HTL) of microalgae for biofuel production is suffering from low bio-oil yield and high heteroatomic compositions owing to their low efficiency and selectivity to hydrolysis of cellular compounds. Hereby we report Keggin-type (MoÀ VÀ P) heteropolyacids (HPAs)-catalyzed HTL of microalgae for efficient low-nitrogen biocrude production. The increases of reaction temperature, reaction time, and vanadium substitution degrees of HPAs are favorable to biocrude yield initially, whereas a significant decrease of biocrude yield is observed owing to the enhanced oxidation of carbohydrates above the optimum reaction conditions. The maximum biocrude yield of HPAs-catalyzed HTL of microalgae is 29.95 % at reaction temperature of 300°C, reaction time of 2 h, and 5 wt% of HPA-4, which is about 19.66 % higher than that of control with 71.17 % less N-containing compounds, including 1,3-propanediamine, 1-pentanamine, and 2, 2'heptamethylene-di-2-imidazoline than that of control. This work reveals that HPAs with Brønsted acidity and reversible redox properties are capable of both enhancing biocrude production via catalyzing the hydrolysis of cellular compounds and reducing their nitrogen content through avoiding the Maillard reactions between the intermediates of hydrolysis of carbohydrates and proteins. HPAs-catalyzed HTL is an efficient strategy to produce low N-containing biofuels, possibly paving the way of their direct use in modern motors.

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Section: Resultsmentioning

confidence: 99%

Section: Effect Of Reaction Time On Hpas-catalyzed Htlmentioning

confidence: 99%

Keggin‐type Heteropolyacids‐Catalyzed Selective Hydrothermal Oxidation of Microalgae for Low Nitrogen Biofuel Production

Shen

Long

et al. 2020

ChemSusChem

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“…In recent times, heteropolyacids have been recognized for their versatile function (acid-base characteristics and redox power). The most important role of heteropolyacids has been their use for oxidizing organic substrates under mild reaction conditions [28][29][30].…”

Section: Heteropolyacid (Hpa) Catalytic Oxidation Systemmentioning

confidence: 99%

A Comprehensive Review on Catalytic Oxidative Desulfurization of Liquid Fuel Oil

2019

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The production of green fuel oil is of the utmost importance for maintaining a healthy life and environment in the current world. Effective and complete removal of sulfur refractory compounds (such as 4,6-dimethyldibenzothiophene and other alkyl-substituted thiophene derivatives) from fuel oil is essential to meet the new requirements of sulfur standards. Several techniques have been proposed for desulfurization of fuel oil, such as hydrodesulfurization (HDS), selective adsorption, extractive distillation, biodesulfurization, and oxidative desulfurization (ODS). The removal of sulfur by the HDS process requires higher investment costs, high reaction temperature (up to 400 °C), and high pressure (up to 100 atm) reactors. On the other hand, studies have shown that the ODS process is remarkably successful in the removal of sulfur under mild reaction conditions. This review article presents a comparative analysis of various existing catalytic oxidation techniques: acetic acid/formic acid catalytic oxidation, heteropolyacid (HPA) catalytic oxidation, ionic liquid catalytic oxidation, molecular sieve catalytic oxidation, polyoxometalates catalytic oxidation, titanium catalytic oxidation, and ultrasound-assisted oxidation systems, as well as discusses research gaps, and proposes important recommendations for future challenges.

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“…Keggin heteropolyacids (HPAs) are a class of metal‐oxygen clusters with a high Brønsted acidity and are widely applied in a plethora of acid‐catalyzed reactions . These solid polyoxometalates presents a large variety of composition, structure and electronic properties, which makes them versatile catalysts in different reactions .…”

Section: Introductionmentioning

confidence: 99%

“…Keggin heteropolyacids (HPAs) are a class of metal-oxygen clusters with a high Brønsted acidity and are widely applied in a plethora of acid-catalyzed reactions. [1,2] These solid polyoxometalates presents a large variety of composition, structure and electronic properties, which makes them versatile catalysts in different reactions. [3] Therefore, in addition to be active in acid-catalyzed reactions, Keggin HPAs are also effective catalysts in oxidation reactions of different substrates.…”

Section: Introductionmentioning

confidence: 99%

Cesium‐Exchanged Lacunar Keggin Heteropolyacid Salts: Efficient Solid Catalysts for the Green Oxidation of Terpenic Alcohols with Hydrogen Peroxide

2020

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In this work, an innovative and green oxidative process to convert renewable and abundant raw material to more value‐added fine chemicals was developed. Hydrogen peroxide, an environmentally benign oxidant, was used in Cs–exchanged lacunar Keggin heteropolyacid salts‐catalyzed oxidation reactions of the terpenic alcohols (i. e., nerol was the model molecule). The activity of most outstanding catalyst (Cs8SiW11O39) was compared with various catalysts. Epoxides and aldehydes, which are an attractive feedstock for fragrance and pharmaceutical industries were selectively obtained. Lacunar Keggin heteropolyacid salts containing cesium as the counter ion (i. e., Cs7PW11O39, Cs7PMo11O39 and Cs8SiW11O39) were easily synthesized and characterized by infrared spectroscopy, powdered X‐rays diffraction, X‐rays dispersive spectroscopy, scanning electronic microscopy, thermal analysis, porosimetry analyses, diameter and pores distribution. The influences of the main reaction variables such as catalyst concentration, the stoichiometry of the reactants and reaction temperature were evaluated. The reaction scope was successfully extended to the other terpenic alcohols. The Cs8SiW11O39 was the most active and selective lacunar salt. After five cycles of successive reuse, no loss of catalytic activity or selectivity was observed.

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An unexpected behavior of H₃PMo₁₂O₄₀heteropolyacid catalyst on the biphasic hydrolysis of vegetable oils

Abstract: Fatty acids (FA) are key ingredients in formulating numerous high-value chemicals.

Cited by 26 publications

References 39 publications

Keggin‐type Heteropolyacids‐Catalyzed Selective Hydrothermal Oxidation of Microalgae for Low Nitrogen Biofuel Production

Keggin‐type Heteropolyacids‐Catalyzed Selective Hydrothermal Oxidation of Microalgae for Low Nitrogen Biofuel Production

A Comprehensive Review on Catalytic Oxidative Desulfurization of Liquid Fuel Oil

Cesium‐Exchanged Lacunar Keggin Heteropolyacid Salts: Efficient Solid Catalysts for the Green Oxidation of Terpenic Alcohols with Hydrogen Peroxide

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