Hydrogenation Of Sunflower Oil Research Articles

Liquid-phase hydrogenation of sunflower oil over platinum and nickel catalysts: Effects on activity and stereoselectivity

This study presents the results of comparative hydrogenation of sunflower oil over a platinum catalyst supported on activated diatomite and an industrial nickel catalyst (Pricat-9910). Catalysts are characterized using physical methods, such as transmission electron microscopic, temperature programmed hydrogen desorption, Brunauer–Emmett–Teller and inductively coupled plasma atomic emission spectrometry, enabling the determination of the size of catalyst particles, forms of adsorbed hydrogen, and specific surface area. Depending on the process conditions, hydrogenation reaction rates on platinum catalysts have been found to be 2–5 times higher than cis-trans isomerization reaction rates. Using a nickel catalyst, the hydrogenation and isomerization rates at low temperatures (110°C-130 °C) and 0.5 MPa pressure are almost similar, while, the hydrogenation rate is 1.4–1.8 times lower than the isomerization rate at high temperatures and pressures, leading to the formation of a large number of trans isomers. The difference in catalysts selectivity may be attributed the speciation and different adsorption energies of surface hydrogen, leading to the possibility of simultaneous hydrogenation of linoleic and oleic acids on the nickel catalyst.

NEW STEREOSELECTIVE CATALYSTS FOR THE HYDROGENATION OF SUNFLOWER OIL

The work is devoted to the creation of new stereoselective catalysts for the hydrogenation of sunflower oil, which can significantly reduce the trans-isomers of fatty acids. Thus, on nickel catalysts used in industry, the content of trans-isomers of fatty acids reaches up to 30%. Platinum deposited on diatomite (processed natural clay) 0.2 to 1% is offered as a catalyst. Methodology. The hydrogenation was carried out in an autoclave, excluding external diffusion inhibition, at hydrogen pressures ranging from 0.25 to 1.0 MPa and temperatures ranging from 90 to 110°C. Results and discussion. Chromatographic analysis was used in all cases to determine the isomeric composition of fatty acids, making it possible for the first time to change hydrogen pressure and reaction temperature without changing the isomeric composition. This allows the study of how stereoisomeric composition changes during the hydrogenation of fatty acids. Various physical methods are used to verify catalysts: TPD, BET, and TEM, etc., which can determine catalyst particle size, hydrogen adsorption forms, and specific surfaces. Conclusion. These characteristics were correlated with the activity and stereoselectivity of the studied catalysts. Trans-fatty acids are found to be two to three times lower on platinum catalysts than on nickel catalysts.

Effect of the Nature of Supports and the Degree of Palladium Dispersion on the Catalyst Activity and Selectivity in the Sunflower Oil Hydrogenation Reaction

Effect of the Nature of Supports and the Degree of Palladium Dispersion on the Catalyst Activity and Selectivity in the Sunflower Oil Hydrogenation Reaction

QUANTUM CHEMICAL STUDY OF HYDROGENATION OF SUNFLOWER OIL OVER NICKEL CATALYSTS

Vegetable oil hydrogenation is vital in edible margarine production, preventing rapid deterioration caused by double bond oxidation. Hydrogenation preserves vegetable oils by countering double bond oxidation, ensuring product quality. During this process, geometric isomers, notably trans isomers, form, driven by thermodynamic stability. Nickel catalysts are crucial in the oil and ghee industry for efficient hydrogenation. Purpose. Our study investigates the hydrogenation of sunflower oil with nickel catalysts, aiming to uncover molecular dynamics and interactions shaping this process. We reveal essential insights into linoleic acid-nickel interactions, elucidating hydrogenation mechanisms and implications for glycerol production. Methodology. Quantum chemical calculations and HyperChem software were employed to study the linoleic acid-nickel interaction during hydrogenation. This study delves into the hydrogenation of sunflower oil using nickel catalysts, employing quantum chemical calculations and HyperChem software. Results. Our research elucidates robust linoleic acid-nickel interactions through optimized structures, molecular electrostatic maps, molecular orbitals, bond lengths, and energies. These findings enhance our understanding of hydrogenation mechanisms. Additionally, we found that nickel-metal interactions primarily drive glycerol production from biofuels, promising efficiency gains. Conclusion. Our study yields insights into vegetable oil hydrogenation with nickel catalysts, optimizing processes in the oil and ghee industry. Furthermore, it has implications for glycerol production from biofuels, offering potential advancements in this area.

The effect of the support nature and palladium dispersion on activity and selectivity of the palladium catalyst in hydrogenation of sunflower oil

Samples of the powdered catalysts Pd/C and Pd/Ox, which were synthesized by depositing 0.5 and 1.0 wt.% Pd on carbon materials (Sibunit 159k, thermal black Т-900, Vulcan XC-72R) and oxide supports (Ox: γ-Al2O3, Cr2O3, Ga2O3, TiO2, Ta2O5 and V2O5, and kieselguhr FW-70), were studied. Their catalytic properties were investigated in the partial hydrogenation of sunflower oil. Comparative testing of the catalysts was performed in the kinetic mode using a static Parr reactor to estimate their activity and trans-isomerization selectivity. The effect of the average size of supported palladium particles (dCO) on the indicated characteristics in a wide range of dCO values was discussed.

Facet-dependent Pd0-O2−-Ce3+ active site for selective hydrogenation of linoleate ester to cis oleic acid ester

Reducing the formation of trans fatty acid in vegetable oil hydrogenation process is of significance to ensure food safety. Herein, Pd0-O2−-Ce3+ active site was constructed by strong electronic interactions between Pd0 and CeO2-Polyhedrons to promote the formation of cis fatty acid. Results reveal that the abundant oxygen vacancies of CeO2 (111) facets promote the adsorption and activation of hydrogen, leading to excellent catalytic activity of Pd/CeO2-Polyhedrons. Moreover, electronic reconstructed Pd0-O2−-Ce3+ active site limits the σ-bond rotation of half-hydrogenated intermediates through enhancing π backdonation and weakening the σ-bond, contributing to the reduction of trans products. Under mild conditions (30 °C, 0.3 MPa H2, and 2 h), Pd/CeO2-Polyhedrons catalyst shows exceptional methyl oleate selectivity of 52.6% with 93.8% conversion for sunflower oil hydrogenation. The catalyst has been further extended to the selective hydrogenation to several other vegetable oils such as sunflower oil, peanut oil, soybean oil, among others, under mild conditions.

Economic analysis for the hydrogenation of sunflower oil using Pt monolith catalysts

In the present work, the economic feasibility of the hydrogenation of vegetable oil using a platinum structured catalyst in a monolithic stirrer reactor (MSR) is examined. An 80 t day−1 hydrogenation plant with a reactor with a capacity of 10 t and a final product with 70 iodine index was selected. The study considered process equipment made of carbon steel and A304 stainless steel. Through simulation, the optimal conditions for the hydrogenation performed adiabatically were determined in order to reduce the processing costs: initial reaction temperature = 453 K, hydrogen pressure = 7 atm, stirrer speed = 200 rpm, and catalyst loading = 0.04 kgPt,sup m−3. The economic indicators showed that the proposed catalytic process is profitable, with a higher net present value using carbon steel instead of stainless steel A304. The sensitivity analysis revealed that vegetable oil cost is the most influential variable on the economy of the project, followed by hydrogen consumption and taxes. The changes in labor costs and catalyst recovery were negligible. The selection of A304 stainless steel carries a considerable economic risk, whereas when using carbon steel, the risk is lower, showing promising profit.

Hydrogenation of vegetable oil using highly dispersed Pt/γ‐Al2O3 catalyst: Effects of key operating parameters and deactivation study

AbstractIn the present work, Pt/γ‐Al2O3 catalysts with high metal dispersion were prepared and characterized using chloroplatinic acid and platinum acetylacetonate as metal precursors. The activity and selectivity of the catalysts were evaluated in the hydrogenation of sunflower oil. A comprehensive analysis of the effects of key operational parameters on catalytic performance was carried out. The experimental variables were hydrogen pressure (275.8–551.6 kPa), temperature (160–200°C), and catalyst loading (0.005–0.015 kg Ptexp/m3oil). Platinum catalysts were active, with a double bond conversion of 28% at 2 h. The metal precursor affected catalyst selectivity. The catalyst prepared with chloroplatinic acid exhibited a lower formation of trans‐isomers compared with Pt acetylacetonate. The γ‐Al2O3 supported platinum catalyst with a metal loading of 0.51 wt.% and a metal dispersion of 98% maintained its initial catalyst activity and selectivity after 10 consecutive uses (1200 min accumulate operation time), without changes in its catalytic properties. The obtained results suggested that Pt catalysts are an attractive alternative to conventional nickel catalysts for the hydrogenation of vegetable oil.

Sunflower Hydrogenation in Taylor Flow Conditions: Experiments and Computational Fluid Dynamics Modeling Using a Moving Mesh Approach

Sunflower oil hydrogenation was carried out in a 2 mm diameter jacketed capillary reactor coated with a Pd/Al2O3 catalyst, mimicking a channel of a heat exchanger monolith reactor. The operating co...

Highly stable platinum monolith catalyst for the hydrogenation of vegetable oil

In the present work, a novel structured platinum catalyst where the Pt is supported on an anodized aluminum monolith was studied for the hydrogenation of sunflower oil. The catalytic tests were carried out in a monolithic stirred semi-batch reactor at temperatures between 433 and 473 K, and hydrogen pressures from 2.7 to 5.4 atm. The monoliths were prepared using H2PtCl6 and Pt(C5H7O2)2 metal precursors and characterized by temperature programmed reduction, N2 adsorption isotherms, H2 chemisorption, scanning electronic microscopy, inductively coupled plasma-atomic emission spectroscopy, and ultrasound adherence tests. Response surface methodology was used to study the relationship between the process variables and C = C conversion, concentration of trans-isomers and selectivity toward monosaturated (S1) and saturated (S2) fatty acids.The catalysts showed to be active, reaching a conversion of 18% at 120 min. The H2PtCl6 impregnated monolith exhibited low selectivity towards trans-isomer formation, maintaining its initial catalyst activity after 40 consecutive uses, without modifications on S1 and S2. The results indicated that platinum monolith catalysts could be an affordable alternative to commercial Ni catalysts, removing the filtration and bleaching stages, hence reducing the processing costs.

Partial hydrogenation of sunflower oil on platinum catalysts: Influence of process conditions on the mass content of geometric isomers

In this work, γ-Al2O3 supported Pt catalysts (Pt/γ-Al2O3) were prepared by adsorption method. The characteristics of the Pt catalysts were evaluated using X-ray diffraction, nitrogen adsorption, CO chemisorption analysis and transmission electron microscopy. The influence of temperature, partial pressure of hydrogen, concentration of catalyst, and agitation speed on the formation of trans isomers during hydrogenation of sunflower oil was investigated. The results indicated that the prepared Pt catalysts exhibit excellent activity and selectivity and produce solid fat that meet the international standards, owing to the considerable decrease in the percentage of trans isomers. Low concentration of platinum (0.2%) and the possibility to reuse it opens up new perspectives for its industrial application in the process of partial hydrogenation of vegetable oils.

Sunflower oil hydrogenation mechanisms and kinetics

A kinetic model for sunflower oil hydrogenation on a palladium catalyst is proposed based on Horiuty–Polanyi type mechanism and considering either a dissociative or associative adsorption of hydrogen. The derived kinetic laws allow to explain the distinct dependency of saturation and isomerization reactions on hydrogen pressure. Kinetic parameters are identified based on batch slurry hydrogenations carried out at 60–160°C and 2–31 bar with a powdered Pd/Al 2 O 3 catalyst. A statistical analysis is used to select the most suitable adsorption mechanism for H 2 . Evaluation of the Weisz–Prater modulus reveals that limitations to intraparticle diffusion occur despite the particle diameter does not exceed 40 μ m. • Kinetic model for sunflower oil hydrogenation based on Horiuti–Polanyi mechanism • Examination of dissociative and associative hydrogen adsorption mechanisms • Discrimination of hydrogen pressure effect on saturation and isomerization reactions • Experimental validation carried out with Pd/Al 2 O 3 powdered catalyst • Optimization and statistical analysis of the kinetic parameters

Ultrasound-assisted sequentially precipitated nickel-silica catalysts and its application in the partial hydrogenation of edible oil

Sequentially precipitated Mg-promoted nickel-silica catalysts with ageing performed under various ultrasonic intensities were employed to study the catalyst performance in the partial hydrogenation of sunflower oil. Results from various characterisation studies showed that increasing ultrasonic intensity caused a higher degree of hydroxycarbonate erosion and suppressed the formation of Ni silicates and silica support, which improved Ni dispersion, BET surface area and catalyst reducibility. Growth of silica clusters on the catalyst aggregates were observed in the absence of ultrasonication, which explained the higher silica and nickel silicate content on the outer surface of the catalyst particle. Application of ultrasound also altered the electron density of the Ni species, which led to higher activity and enhanced product selectivity for sonicated catalysts. The catalyst synthesised with ultrasonic intensity of 20.78 Wcm−2 achieved 22.6% increase in hydrogenation activity, along with 28.5% decrease in trans-C18:1 yield at IV = 70, thus supporting the feasibility of such technique.

Intensified Catalytic Transfer Hydrogenation of Sunflower Oil Using Ultrasound

The present work deals with CTH of sunflower oil focusing on establishing the best conditions of ultrasonic operating and reaction parameters to maximize the extent of hydrogenation of sunflower oil. The processing is based on the use of 5% Pd/C as the catalyst, ammonium formate as the hydrogen donor and water as solvent. Effect of ultrasonic power, ultrasonic frequency, temperature, speed of agitation, catalyst loading and water quantity on the extent of CTH has been investigated. Under the best operating conditions of ultrasonic power as 150 W, 22 kHz as frequency, 30oC as the reaction temperature, 800 rpm as the agitation speed, 2% w/w as the catalyst loading and 50 mL of water, maximum reduction in iodine value was obtained from 141.65 to 87.24 g/100g of oil. It was also demonstrated that use of ultrasound resulted in significant intensification (final acid value of 87.24 g/100g of oil) as compared to the conventional approach based on only stirring (final acid value of 105.85 g/100g of oil). Overall ...

Mg-Ni supported on perlite as hydrogenation catalyst: Influence of Mg and Ni content

Use of broken honeycomb-like expanded perlite as support for magnesium modified nickel catalysts in process of partial hydrogenation of sunflower oil was studied. By the use of the precipitation-deposition method, two groups of precursors were synthesized: different Ni/SiO2 mole ratios with constant Mg/Ni mole ratio 0.1, and different Mg/Ni mole ratios with constant Ni/SiO2 mole ratio 0.25. Characterizations of precursors were done (scanning electron microscopy, diffuse reflectance UV?Vis, infrared spectroscopy, N2-physisorption, temperature programmed reduction (TPR) and He-pycnometry) to determine the material differences, considering the change in morphology, structure, texture and reducibility with overall Ni and Mg content. In addition, TPR and hydrogen chemisorption were performed in order to estimate the temperature reduction range of supported precursors and the dispersion degree of nickel in reduced precursors, respectively. The interaction between Ni2+ and perlite support was established. Different reducibility and dispersion were obtained as a function of Ni/SiO2 and Mg/Ni mole ratios. After the precursor?s reduction and paraffin oil impregnation, the obtained catalysts were tested in a sunflower oil hydrogenation reaction. Catalyst activity was monitored through the decrease of the refractive index and hydrogen consumption that gave the insight that the influence on catalyst activity represents the accessibility of triacylglycerols and not always the hydrogen determined dispersion degree.

Monolithic stirrer reactor for vegetable oil hydrogenation: A technical and economic assessment

The monolithic stirrer reactor (MSR) which consists on monolithic structures mounted on reactor axis as agitator blades is a novel design with the potential to intensify different production processes. Its most outstanding advantages are the absence of a filtering stage after the reaction and the high-speed mass transfer. In this paper, the technical and economic feasibility of sunflower oil hydrogenation process under MSR (Pd/Al2O3/Al) configuration was studied considering a 100 ton day−1 productive plant, a 20 ton capacity reactor and a final product with 75 iodine index. Moreover, several reaction conditions were taken into account, such as catalyst loading and initial and final reaction temperatures, in order to determine the operating costs. The proposed alternative process could be profitable, displaying a higher Net Present Value (NPV) than the conventional technology one. However, slight variations in the monolithic catalyst cost performed through a sensitivity analysis generate a considerable decrease in NPV, thus determining that the implementation of the proposed alternative technology presents a high economic risk. The achieved results in this study indicate that further research is necessary in order to develop a regenerating procedure to extend the catalyst useful life, thus favouring the monolithic technology economy.

Effects of ZnO on Characteristics and Selectivity of Coprecipitated Ni/ZnO/Al2O3Catalysts for Partial Hydrogenation of Sunflower Oil

Ni/ZnO/Al2O3 catalysts at different molar ratios were synthesized and characterized, and the catalytic performances were assessed by partial hydrogenation of sunflower oil. Ni:Zn at various molar ratios have resulted in varying degrees of Ni and Zn migration from the bulk to the catalyst surface, which led to different pore characteristics. Catalysts with equimolar Ni:Zn have shown wider pores and higher pore volumes and achieved 23% higher hydrogenation activity than Ni/Al2O3. The presence of ZnO also led to higher Ni surface area and dispersion, and TEM images have indicated that this could be attributed to ZnO that acts as a spacer for the Ni crystallites. However, the Ni surface area diminishes as the ZnO content becomes higher. The presence of ZnO in Ni/ZnO/Al2O3 catalysts is also shown to lower trans-fats formation when wide pores are available.

Hydrogenation of Sunflower Oil over M/SiO2 and M/Al2O3 (M = Ni, Pd, Pt, Co, Cu) Catalysts

AbstractThis work is aimed at evaluating the performance of several catalysts in the partial hydrogenation of sunflower oil. The catalysts are composed of noble (Pd and Pt) and base metals (Ni, Co and Cu), supported on both silica and alumina. The following order can be proposed for the effect of the metal on the hydrogenation activity: Pd > Pt > Ni > Co > Cu. At a target iodine value of 70 (a typical value for oleomargarine), the production of trans isomers is minimum for supported nickel catalysts (25.7–32.4 %, depending on the operating conditions). Regarding the effect of the support, Al2O3 allows for more active catalysts based on noble metals (Pd and Pt) and Co, the effect being much more pronounced for Pt. Binary mixtures of catalysts have been studied, in order to strike a balance between catalyst activity and product distribution. The results evidence that Pd/Al2O3–Co/SiO2 mixture has a good balance between activity and selectivity, and leads to a very low production of trans isomers (11.8 %) and a moderate amount of saturated stearic acid (13.5 %). Consequently, the utilization of cobalt‐based catalysts (or the addition of cobalt to other metallic catalysts) could be considered a promising alternative for the hydrogenation of edible oil.

Magnetic Mesoporous Palladium Catalyzed Selective Hydrogenation of Sunflower Oil.

In this paper, a novel magnetic mesoporous Pd catalyst is used to catalyse selective hydrogenation of sunflower oil at a mild temperature of 50°C. Effects of reaction temperature, stirring speed, time, catalyst loading and hydrogen pressure on the reaction activity, trans fatty acid (TFA) and stearic acid formation were studied. Under the condition of 3.2 mg Pd/100 g oil, 50°C, 1300 rpm stirring speed and 19.0 atm of H2, the lowest amount of TFA generated during the reaction (IV = 80) was 14.9 ± 0.4% while 11.4 ± 0.4% of stearic acid was produced. And this magnetic Pd-catalyst can be reused easily for at least six times without significant catalyst deactivation, the amount of TFA almost remained unchanged. Moreover, this Pd-catalyst shows a good magnetic separation, which provides a potential method for the facile oil modification.

Perlite as a potential support for nickel catalyst in the process of sunflower oil hydrogenation

Investigation was conducted in order to elucidate the possibility of using perlite as support for preparation of nickel based precursor catalyst, potentially applicable in vegetable oil hydrogenation process. On three differently prepared expanded perlite, nickel catalyst precursors with identical Ni/SiO2 = 1.1 and Ni/Mg = 10/1 ratios were synthesized by precipitation-deposition method. Different techniques, SEM micrography, He-pycnometry, calcimetry, Hg-porosimetry, N2-physisorption, H2-chemisorption and temperature programmed reduction, were used for characterization of obtained samples. Determining the precursor texture, morphology and reducibility shows a successfully deposited nickel phase on perlite support with promising properties for vegetable oil hydrogenation. Chosen precursor was reduced and passivated in paraffin oil and the obtained catalyst showed significant catalytic activity in the test of sunflower oil hydrogenation.