Kinetics of liquid phase hydrogenation of cottonseed oil with nickel catalysts

Krisnaiah, D.; Sarkar, Shaibal K.

doi:10.1007/bf02540649

Cited by 14 publications

(7 citation statements)

References 8 publications

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“…Other authors [42] arrive at a first order in hydrogen for dienes and an order of 3/2 for monoenes when hydrogenating in the gas phase, or conclude [43] that the rate of linoleate disappearance is proportional to the square root of the hydrogen concentration. This latter conclusion is in accordance with the mechanism outlined above, which also holds for the conclusion [35] that the hydrogenation of methyl oleate is first order in hydrogen.…”

Section: Order In Hydrogenmentioning

confidence: 99%

Revisiting the formation of trans isomers during partial hydrogenation of triacylglycerol oils

Dijkstra¹

2006

Euro J Lipid Sci & Tech

135

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The decisions to limit (Europe) or declare (USA) the trans isomer content of certain fatty foodstuffs have caused a demand for hardstocks with a reduced trans isomer content. One way to produce such hardstocks is by interesterifying high-melting components such as palm stearin or fully hydrogenated vegetable oils with lauric or liquid oils. Another way is to modify the hydrogenation process. Possible modifications are reviewed. A moderate reduction in trans isomer content results from operating the hydrogenation process at much reduced temperature, but this also leads to an increase in saturates. Larger reductions in trans isomers may well be made possible by the recent development of new catalysts. One development involves the use of zeolites that allow the rather straight trans isomer to enter the pores while keeping the more curved cis isomers outside. The other development involves a precious metal catalyst that may have been modified in such a way that it has a reduced affinity for monounsaturated fatty acid moieties.

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Section: Order In Hydrogenmentioning

confidence: 99%

Revisiting the formation of trans isomers during partial hydrogenation of triacylglycerol oils

Dijkstra¹

2006

Euro J Lipid Sci & Tech

135

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“…The activation energies are in very good agreement with that of 100 kJ/mol reported by Susu (1982) in the hydrogenation of groundnut oil. Lower values have been reported by Gut et al (1979), about 20 kJ/mol for sunflower seed oil, and Krishnaiah and Sarkar (1990), 49.2 kJ/mol for cottonseed oil. Marangozis et al (1977) report activation energies in the hydrogenation of different vegetable oils in the range 26.3-150 kJ/mol, the lower values attributed to mass-transfer control.…”

Section: Kinetic Studiesmentioning

confidence: 38%

Control of the product distribution in the hydrogenation of vegetable oils over nickel on silica catalysts

et al. 1998

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Several nickel on silica catalysts, prepared by impregnation or precipitatioddeposition, and a commercial catalyst were tested for activity and selectivity in the sunflower seed oil hydrogenation. An average turn-over frequency of 2.57 s-I was found for the catalysts, assuming inaccessibility of nickel in pores smaller than 2 nm and a constant nickel surface concentration poisoned by the reaction mixture. After studying the mass-transfer steps, the effect of temperature (373-453 K) and pressure (101-608 kPa) on reaction rates in the kinetic regime was analyzed, and the corresponding apparent activation energies and reaction orders were obtained. Conclusions on the effect of temperature and pressure on the selectivity to the preferential hydrogenation of polyunsaturates (So) and to the formation of trans-isomers ((SEo,,J0) in the kinetic regime were derived from the results. Finally, a similar analysis was carried out when diffusion limitations were known to be present.Plusieurs catalyseurs de nickel sur de la silice, prepares par impregnation ou precipitationldep6t. en un catalyseur commercial ont ete testes en termes de leur selectivite dans I'hydrogenation d'huile de tournesol. On a trouve une frequence de renouvellement moyenne de 2,57 s-' pour les catalyseurs, en supposant I'inaccessibilite du nickel dans les pores inferieures a 2 nm et une concentration de surface de nickel constante empoisonnee par le melange de la reaction. Apres avoir etudie les etapes du transfert de matiere, on a analyse I'effet de la temperature (37-53 K) et de la pression (101408 kPa) su; les vitesses de reaction dans le regime cinetique, et on a obtenu les energies d'activation apparentes correspondantes. A partir des resultats, des conclusions ont ete tirees sur I'effet de la temperature et de la pression sur la selectivite a I'hydrogenation preferentielle des polyinsatures (So) et a la formation de trans-isomeres ((Spqn,J0) dans le regime cinetique. Enfin, une analyse similaire a ete menee lorsqu'on a su qu'il y avait des limitations de diffusion.

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“…Modeling of the Kinetics An attempt was made to approximately model the experimental data obtained at 2-bar hydrogen pressure. In the literature, a simple model involving linoleic, cis 18:1, TFA, and 18:0 was often used [17,18,[28][29][30][31][32][33]. Because the GC analysis could distinguish 9-octadecenoate (9-18:1) versus 12-octadecenoate (12-18:1), we decided to use a model (shown in Scheme 1) where 9-18:1 and 12-18:1 followed different pathways.…”

Section: Effect Of IV and Hydrogen Pressure On Tfamentioning

confidence: 99%

Comparison of Soybean and Cottonseed Oils upon Hydrogenation with Nickel, Palladium and Platinum Catalysts

Cheng¹,

Rau²,

Dowd³

et al. 2014

J Americ Oil Chem Soc

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There is current interest in reducing the trans fatty acids (TFA) in hydrogenated vegetable oils because consumption of foods high in TFA has been linked to increased serum cholesterol content. In the interest of understanding the TFA levels, hydrogenation was carried out in this work on soybean oil and cottonseed oil at two pressures (2 and 5 bar) and 100°C using commercially available Ni, Pd, and Pt catalysts. The TFA levels and the fatty acid profiles were analyzed by gas chromatography. The iodine value of interest is *70 for all-purpose shortening and 95-110 for pourable oil applications. In all cases, higher hydrogen pressures produced lower levels of TFA. In the range of 70-95 iodine values for the hydrogenated products, the Pt catalyst gave the least TFA, followed closely by Ni, and then Pd, for both oils. For all three catalysts at 2-and 5-bar pressures and 70-95 iodine values, cottonseed oil contained noticeably less TFA than soybean oil; this is probably because cottonseed oil contains a lower total amount of olefin-containing fatty acids relative to soybean oil. Approximate kinetic modeling was also done on the hydrogenation data that provided additional confirmation of data consistency.

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Kinetics of liquid phase hydrogenation of cottonseed oil with nickel catalysts

Cited by 14 publications

References 8 publications

Revisiting the formation of trans isomers during partial hydrogenation of triacylglycerol oils

Revisiting the formation of trans isomers during partial hydrogenation of triacylglycerol oils

Control of the product distribution in the hydrogenation of vegetable oils over nickel on silica catalysts

Comparison of Soybean and Cottonseed Oils upon Hydrogenation with Nickel, Palladium and Platinum Catalysts

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