File Name: hydrogenation of fats and oils theory and practice .zip
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The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric. Find more information on the Altmetric Attention Score and how the score is calculated. Selective hydrogenation of vegetable oils is a significant step in the synthesis of several precursors for the preparation of bioplastics and biodiesel. In this work, a commercial Lindlar catalyst palladium on calcium carbonate; poisoned with lead was used as an efficient catalyst in the selective partial hydrogenation of canola and sunflower oils.
Different operating conditions pressure, temperature, and catalyst amount were tested, and results were achieved by gas chromatography analysis of methyl esters obtained by the transesterification of the triglycerides. The optimized reaction conditions 0. Figure 1. BET isotherms left. BJH adsorption and desorption pore diameter size distribution right. Figure 5. C and C conversions at 1 h over five repeated tests and B hydrogenated oil composition at 1 h over five repeated tests.
Also, if not directly poison, Pd can occlude the pores of the catalyst preventing access for reactants;. Figure 6. Test Figure 7. Figure 8. Figure 9. Example of data with respective calculated compositions for test canola rapeseed oil left and test sunflower oil right. These two tests were repeated for a shorter time: 1 h with higher sampling frequency 10 min vs 30 min. It is possible to see the combined results in Figures 2 and 3 ; the reaction trend is confirmed.
Figure Lab-scale plant reactor for hydrogenation of oils and their derivatives. More by Umberto Pasqual Laverdura. More by Leucio Rossi. More by Francesco Ferella. More by Claire Courson. More by Antonio Zarli. More by Rasha Alhajyoussef.
More by Katia Gallucci. Cite this: ACS Omega , 5 , 36 , — ACS AuthorChoice. Article Views Altmetric -. Abstract High Resolution Image. The valorization of vegetable oils and their products represents a sustainable alternative to petrochemicals and renewable building blocks in industrial applications.
Since the 19th century, vegetable oils found widespread applications in the chemical industry and transports and then were quite completely substituted due to oil drilling exploitation; nevertheless, the recent renewed interest is largely addressed as a raw material for the production of biofuels and fine chemicals.
These characteristics facilitate industrial use in continuous processes of transformation. The oleochemical industry is a major producer of bio-based products, such as important products of unsaturated oils soybean, sunflower, and linseed oil, include alkyd resins, linoleum, and epoxidized oils , that are sources for bio-lubricants at low viscosity, combined with high oxidative and thermal stability.
This is due to a growing interest of the developed countries North America and Europe promoted by government regulations in more intensive bio-based compounds. One of the main issues in industrial exploitation is the intrinsically variable composition of the raw material. The fatty acids usually observed in vegetable oils are oleic acid C c , linoleic acid C cc , linolenic acid C ccc , and stearic acid C ; 18 other secondary compounds are arachidonic acid C , palmitic acid C , and in non-canola rapeseed oil also erucic acid C and C c.
The selective heterogeneous catalytic hydrogenation of highly unsaturated oils is a key process to the monoene production, addressed to a wide range of biocompatible products green chemicals, bio-lubricants, poly-oils, etc. The state of the art selective catalytic hydrogenation reports several efforts devoted to the search of catalysts producing minimal amounts of trans isomers. The wide interest in Pd-based catalysts is justified by its reusability, stability, and high catalytic activity with appreciable monoene selectivity.
To enhance catalyst recovery, after-reaction magnetic supports were also implemented. Finally, the introduction of Pb on the Pd catalysts increases the selectivity toward monoene, lowering the hydrogenation activity. In the first one, the sintering of the Pd particles after reduction with Pb was observed; 56 in the latter, a change in the interatomic spacing occurred. Lindlar catalyst is a commercially available catalyst generally used in hydrogenation reactions, for example, the hydrogenation of alkynes to alkenes; further deactivation with quinoline or other amines is used to enhance the selectivity of the catalyst to prevent deep hydrogenation.
The objective of the proposed work concerns the research and application of a catalyst for the saturation of double bonds in the C18 fatty acid molecule, such as linolenic and linoleic, to increase the percentage of oleic with minimum formation of stearic.
The Lindlar catalyst was tested for this purpose at the laboratory scale under different operating conditions; it was chosen for starting this first work because of the deactivation of palladium that should make it more selective toward the formation of C Although the Lindlar catalyst cost could be too high in order to produce a large amount of commodities, its selectivity is difficult to control and it is potentially environmentally hazardous; however, its performance is interesting to explore for the production of chemicals and precursors at high added value and as reference material for new original catalysts.
In particular, the test campaign is carried out at mild pressure conditions compared to the typical industrial values. Results and Discussion. N 2 adsorption curves Figure 1 permitted the identification of macroporous material isotherm type II. The isotherms have a small hysteresis of type H3; this isotherm shape is reported in the literature as pseudo-type II. It was possible to evaluate a low surface area S BET 4. High Resolution Image.
Commercial canola rapeseed oil and commercial sunflower oil were analyzed after transesterification as described above. Each sample of oil was analyzed three times, and the results mean values are shown in Table 1. The canola oil is richer in C c and C and less loaded in C than the sunflower one and could behave differently during hydrogenation.
Table 1. Before the hydrogenation reaction campaign, blank tests, without a catalyst, were carried out under the same conditions for 6 h in order to evaluate some possible homogeneous phase reaction. In this case, the oil was analyzed at the end of the test. They indicate that no homogenous phase reaction occurs, and composition changes are only linked to the error of the gas chromatography GC analysis.
All results from catalytic activity tests performed with canola rapeseed oil are reported in this section. Very different selectivities and conversions were detected depending on different reaction conditions. The evolution in the composition of fatty acids during the reaction time was evaluated. The more significative test results are reported in Tables 2 and 3.
Table 2. Table 3. In these conditions, the catalyst is not active. At higher temperature, conversions of linoleic and linolenic fatty acids increase until almost complete saturation of double bonds in the fatty acid chains. In addition, we observe the rapid isomerization of oleic acid in elaidic acid about This value is below the equilibrium value reported in the literature.
At this time, 8. Figure 2. In this case, we observe When the maximum was achieved, the relative percentage of elaidic acid increases; at 60 min, the composition is Between 60 and 90 min, C reacts faster by hydrogenating and isomerizing simultaneously; SII increased up to 1.
Figure 3. It is interesting to compare the results in Table 3 , when C and C are half reacted. In this condition, Higher pressure of H 2 1. Figure 4. As a high concentration of monoene is desired, preferably in the cis configuration, while keeping a low concentration of stearic acid and trans isomer, it is necessary to stop the reaction before complete conversion of the polyenes.
In order to identify the best reaction conditions and rates, reference was made to the greatest conversion of polyunsaturated fatty acids, the highest concentration of C fatty acids, and the lowest concentration of C t. Table 4. It is worth mentioning that when results at the same conversion are evaluated, with higher pressure, lower amount of trans isomers is found; this is reflected by the lower SII index as reported in Table 4. This effect is in line with similar behavior for other palladium catalysts as reported by Hsu et al.
The lower pressure test seems to be slightly better test 04 vs test 05 from the point of view of the maximum amount of C From the point of view of relative percentages of elaidic acid and stearic acid, better results were achieved at lower pressure in maximum C concentration conditions. In Table 4 , the best results at the optimal condition found with canola oil, after 60 min of reaction, are summarized.
Another suitable use could be in the coatings industry as indicated by Heidbreder et al. The effects of catalyst recycling, catalyst concentration, and vegetable oil type are investigated at the best operative conditions of 0. Repeated tests of 1 h are conducted to evaluate the efficiency of the catalyst after several cycles.
Koseoglu, K. Rhee Edits. Lipid oxidation of Edible Oil, In: C. Casimir, B. David Edits. Canola oil with reduced linolenic acid.
Oils and fats form an important part of a healthy diet. Structurally they are esters of glycerol with three fatty acids called either triacylglycerols or triglycerides. It is these fatty acids that give the functionality to fats. Chemically, they can be divided into four main types — saturated, cis- monounsaturated, cis -polyunsaturated and trans fatty acids. In very broad terms, saturated fatty acids and trans fatty acids are solid at room temperature while the cis -unsaturates are liquid at room temperature.
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As in the first edition, discussion is not confined to vegetable oils, and the hydrogenation technique is considered in detail. The "why" as well as the "how" of hydrogenation are addressed. Written for both production staff who need advice on specific problems and development personnel who seek directions, if not solutions, the book offers direct practical advice along with explanations of why changes occur as they do. The glossary of technical terms contains a more detailed explanation of some features mentioned throughout the text. Gary R.
The hydrogenation of fats and oils and their oleochemical derivatives such as fatty acids, fatty acid esters and fatty nitriles has proven to be a very useful and versatile way to modify these starting materials. This chapter will be limited to discussing exclusively the hydrogenation of carbon-carbon double bonds.
- Мы опустим каждый второй кадр вместе со звуковым сопровождением и постараемся держаться как можно ближе к реальному времени. На подиуме все замолчали, не отрывая глаз от экрана. Джабба нажал на клавиатуре несколько клавиш, и картинка на экране изменилась.
Я поменялся сменой с новым сотрудником. Согласился подежурить в этот уик-энд. Глаза Стратмора сузились. - Странно.
- Стратмор остановился и повернулся к Сьюзан. - Он сказал, что на кольце были выгравированы какие-то буквы. - Буквы. - Да, если верить ему - не английские. - Стратмор приподнял брови, точно ждал объяснений.
Вот что я хочу сказать. Червь Танкадо не нацелен на наш банк данных. - Он откашлялся. - Он нацелен на фильтры безопасности. Фонтейн побледнел.
Прости, я думал… - Зачем вы послали его в Испанию.
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