Catalysts for selective hydrogenation of soybean oil.1 II. Commercial catalysts

A survey of commercial hydrogenation catalysts demonstrated the higher selectivity (S_L= 2.4\s-2.7) of certain platinum, palladium and rhodium catalysts for hydrogenating linolenic components in soybean oil. Nickel catalysts generally showed selectivities below S_L=2.0 although skeletal nickel achieved higher values.Trans-isomers were in the range 7.8\s-15.4% for the above noble metal catalysts. Nickel catalysts provide a lesser degree of isomerization, 5.2\s-7.4% oftrans-isomers for the most selective catalysts. Presented at the AOCS Meeting at Toronto, 1962.     

Catalysts for selective hydrogenation of soybean oil. III. Hydrogenation catalysts prepared on molecular sieves and other supports

A survey of nickel, platinum and palladium catalysts prepared on silicas, aluminas and mo-lecular sieves indicated that the nature of such supports contributed importantly to selective hydrogenation of soybean oil. Nickel-molecular sieve catalysts provided both high hydrogenation selectivity and lowtrans- isomer formation. Some kind of spatial hindrance may be postulated in explanation of the results. Presented at the AOCS Meeting, Toronto, 1962.     

High oleic oils by selective hydrogenation of soybean oil

High oleic (monoene) oils were obtained from soybean oil by selective hydrogenation with copper catalysts. A mixture of nickel and copper chromite catalyst had activity suitable for producing the high monoene oils. A new catalyst (copper-on-Cab-O-Sil) prepared in the Laboratory was more active than commercial copper catalysts. Hydrogenated oils contained 61–72% monoenoic and 14–24% dienoic acids, and there was essentially no increase in stearic acid. Thetrans-isomer content of these oils varied between 17% to 32%. Double bonds in the monoene were distributed along the molecule from C₆ to C₁₅, but were located preferentially in the C₉ position for thecis-monoene and in the C₁₀ and C₁₁ positions for thetrans-monoene. When the iodine value of these high monoene oils was about 90–95, they remained liquid above 28 C. Citric acid treatment reduced the copper content of hydrogenated oils to a level that was comparable to that of the original soybean oil. Presented at the AOCS Meeting, Chicago, October 1967. Food and Agricultural Organization representative from Rumania. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Effect of agitation on selectivity in the hydrogenation of soybean oil

Summary A total of 12 hydrogenations were conducted in the pilot plant. The conditions were such that analyses of the data would furnish information as to the effect of 6 variables on the course of the reaction. The most reliable estimates were obtained for the effect of increasing, by agitation, the dispersion of hydrogen in the oil. The dispersion was accomplished by converting from a simple turbine agitator to a gas dispersing type with easily fabricated parts. This change resulted in a more selective reaction with respect to unsaturates. The change can also result in a shorter reaction time, or in the consumption of less power. Judging from its effects on the course of hydrogenation, agitation cannot simply be defined in terms of speed. Presented at AOCS Press meeting, San Antonio, Tex., Apr. 12–14, 1954. One of the Branches of the Agricultural Research Service, U. S. Department of Agriculture.     

Behavior of hydrogenation catalysts. I. Hydrogenation of soybean oil with palladium

A statistical method for evaluation of catalysts was used to determine the behavior of palladium catalyst for soybean oil hydrogenation. Empirical models were developed that predict the rate,trans-isomer formation, and selectivity over a range of practical reaction conditions. Two target iodine value (IV) ranges were studied: one range for a liquid salad oil and the other for a margarine basestock. Although palladium has very high activity, it offered no special advantage intrans-isomer formation or selectivity. Palladium can substitute for nickel catalyst, at greatly reduced temperature and catalyst concentrations, for production of salad oil or margarine basestock from soybean oil. Presented at the AOCS meeting, Chicago, May 1983.     

Hydrogenation of linolenate. V. Procedure of evaluating hydrogenation catalysts for selectivity

Equations for determining the ratio of hydrogenation rates for linolenate and linoleate acyl groups are derived from kinetic theory. They are based upon the analysis for linolenate after absorption of 0.5 mole of hydrogen by an equal mixture of linoleate and linolenate. This method finds routine application in the evaluation of hydrogenation catalysts for selectivity. Presented at spring meeting, American Oil Chemists' Society, May 1–3, 1961, St. Louis, Mo. This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Ultrasonic hydrogenation of soybean oil

The rate of hydrogenation of soybean oil with either copper chromite or nickel catalysts increased more than a hundredfold with the aid of ultrasonication. In a continuous reaction system, the selectivity with copper catalyst for linolenate reduction was somewhat lower when ultrasonic energy was applied than when not applied. With ultrasonic energy, 87% hydrogenation of linolenate in soybean oil was obtained in 9 sec at 115 psig H₂ with 1% copper chromite at 181 C and 77% linolenate hydrogenation with 0.025% nickel. Without ultrasonic energy, only 59% linolenate hydrogenation was obtained in 240 sec with copper chromite at 198 C and 500 psig H₂ and 68% linolenate hydrogenation in 480 sec with nickel at 200 C and 115 psig H₂. This innovation may offer an important advantage in increasing the activity of commercial catalysts, particularly copper chromite, for fats and oil hydrogenation.     

The hydrogenation of soybean oil

Journal of the American Oil Chemists' Society - 1     

甲醇制汽油副产重油的加氢改质催化剂的研究

开发出了一种甲醇制汽油(MTG)重油加氢改质催化剂。研究了制备方法、分子筛、粘结剂以及工艺条件对催化剂性能的影响,同时还对催化剂进行了300 h寿命考察,结果表明,催化剂具有良好的活性和稳定性。     

Pilot-plant selective hydrogenation of soybean oil: Activation and evaluation of copper-containing catalysts

In pilot-plant tests, the linolenate content of soybean oil was reduced to less than 1% without increasing the saturates, by hydrogenation to an IV of about 115 with an active copper-chromite catalyst. The linolenate-linoleate selectivity ratio (K_Le/K_Lo) was from 9 to 12. Several commercial copper-chromite catalysts were used in hydrogenation tests. The activities of four of five commercial catalysts tested were improved to various degrees by heating in air at 350 C (one was inactive both before and after heating). Examination by differential thermal analysis (DTA) of each catalyst, just as received and then after being heated at 350 C, demonstrated that heating greatly diminished or removed peak areas from the DTA curve. Studies made with one commerical copper-chromium-barium catalyst showed that heating the catalyst was also necessary to gain maximum linolenate-linoleate selectivity in hydrogenating soybean oil. Presented at the AOCS Meeting, New Orleans, May 1967. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Mediator-assisted electrochemical hydrogenation of soybean oil

In this study, formate ion was used as a shuttle for transferring hydrogen to the surface of a hydrogenation catalyst (7% Ni/SiO₂), where the soybean oil was reduced in such a way that the production of deleterious trans fatty acid was greatly reduced. The formate ion was regenerated at the cathode and thus acted as a mediator for the hydrogenation process. The effect of temperature, pH, and applied potential (current) on the fatty acid profile of the hydrogenated soybean oil was determined. The effects of oil and catalyst loadings on the final product quality were also determined. The application of a current density of resulted in hydrogenated product with desired fatty acid composition. Kinetic studies were also performed for experiments conducted at constant potential conditions. A model that assumes: (i) the rate of regeneration of formate from its oxidized form (bicarbonate ion) is limited by the mass transport effects, and (ii) second-order elementary reaction rate expression was developed to describe the hydrogenation reaction was developed and tested. A good correlation between the model predictions and experimental data was observed.     

Catalytic transfer hydrogenation of soybean oil

The catalytic transfer hydrogenation of soybean oil by various hydrogen donors and solvents with palladium-oncarbon catalyst was investigated in batch and continuous modes. The choice of reaction conditions, donor and catalyst allowed the manufacture of partially hydrogenated oils or semi-solid fats with controlled fatty acid contents, iodine value, melting point and solid content index. The level of “iso” forms of fatty acids was similar to, and average initial selectivity was higher than that obtained with gaseous hydrogenation under pressure with a catalyst of the same type. The best results were obtained in aqueous solution with sodium formate as hydrogen donor at 60°C.     

Empirical modeling of soybean oil hydrogenation

Empirical hydrogenation models were generated from statistically designed laboratory experiments. These models, consisting of a set of polynomial equations, relate the operating variables of soybean oil hydrogenation to properties of the reaction and of the fat produced. These properties include reaction rate,trans-isomer content and melting point. Operating variables included in the models were temperature, hydrogen pressure, catalyst concentration, agitation rate and iodine value. The effects of catalyst concentration and agitation rate were found to be significant in determiningtrans-isomer content, which in turn influences the melting characteristics of the hydrogenated oil. Pressures above 30 psig were found to have little effect ontrans-isomer content, although pressure was very important in determining reaction rate. Reaction temperature was observed as the most important factor in determining thetrans-isomer content for a given iodine value. Generally, 50 to 60%trans isomer content is predicted by the model for the iodine value range and operating conditions used in this study. Thus, these predictive models can assist in scaling up hydrogenation processes and in determining the optimum operating parameters for running commercial hydrogenation. Presented at the AOCS Meeting, Chicago, May 1983.     

The electrocatalytic hydrogenation of soybean oil

Soybean oil has been hydrogenated electrocatalytically at a moderate temperature, without an external supply of pressurized H₂ gas. In the electrocatalytic reaction scheme, atomic hydrogen is produced on an active Raney nickel powder cathode surface by the electrochemical reduction of water molecules from the electrolytic solution. Adsorbed hydrogen then reacts with an oil’s triglycerides to form a hydrogenated product. Experiments were carried out at 70°C with a flow-through electrochemical reactor operating in a batch recycle mode. The reaction medium was a two-phase mixture of soybean oil in a water/t-butanol solvent containing tetraethylammoniump-toluenesulfonate as the supporting electrolyte. In all experiments the reaction was allowed to continue for sufficient time to synthesize a brush hydrogenation product. The effects of oil content, applied current, solvent composition, and supporting electrolyte concentration on the efficiency of hydrogen addition to the oil and on the chemical properties of the hydrogenated oil product were determined. The electrohydrogenated oil is characterized by a high stearic acid content and a low percentage of totaltrans isomers, as compared to that produced in a traditional hydrogenation process.     

Palladium- catalyzed hydrogenation of soybean oil

The hydrogenation of soybean oil has been studied using charcoal-supported palladium catalysts at hydrogen pressures between ambient and 70 psig and at temperatures between 80 C and 160 C in three types of stirred reactor. The catalysts employed were 1-10% w/w Pd supported on charcoal and represented differing metal placement on the support. The structure of the catalysts was confirmed by metal surface area measurements, transmission electron microscopy (TEM) and electron spectroscopy for chemical analysis (ESCA). Comparative studies also were carried out under similar conditions using samples of commercial nickel catalysts. Palladium catalysts with the metal placed on the exterior of the charcoal support were the most active and selective at ambient pressure, and although palladium catalysts with metal placed within the charcoal pore system became the most active at higher hydrogen pressures, only the former type of catalyst retained high selec-tivity over the whole temperature and pressure range. Palladium catalysts gave rise to moretrans- acids than nickel, particularly under conditions normally em-ployed with the latter, but if diffusion limitation was avoided, especially at lower temperatures, palladium gave lower quantities oftrans- acid than nickel. In addition, the selectivity of a well designed palladium catalyst was superior to that of nickel and its activity was 15-20 times greater. It is concluded that if palladium is deposited on the exterior of the charcoal so that it is accessible to the triglyceride molecules, then its selectivity and activity is superior to that of nickel, even at low temperatures, at which nickel is inactive. This underlines the importance of choosing the correct preparative route to give optimum metal placement, and it is suggested that when previous studies have indicated that palladium is unselective for fat hardening, it is likely that the metal was not dispersed on the exterior surface of the support. Furthermore, whereas nickel is best used under diffusion-controlled conditions because its selectivity is better in the latter situation palladium should be used under diffusion-free conditions, which implies that very careful attention should be paid to the reactor design.     

Selective hydrogenation of soybean oil. II. Copper-chromium catalysts

Soybean oil was partially hydrogenated at 170 and 200C with 0.5 and 0.1% copper-chromium catalysts, respectively. The reaction proceeded selectively at both temperatures, although selectivity was better at the lower temperature. Both commercial and laboratory-prepared catalysts reduced the linolenic acid to less than 1% and with selectivity ratios (K_Le/K_Lo) ranging from 6 to 13. Since stearate did not increase, linoleate selectivity (K_Lo/K_Ol) was extremely high. About 80% or more of the original linoleic acid remained in the hydrogenated products as measured by the alkali-isomerization method. More conjugated dienes were formed at 200 than at 170C.     

An evaluation of commercial nickel catalysts during hydrogenation of soybean oil

The activities of several commercial nickel catalysts were determined by measuring their activation energies. Among these catalysts, G95E, Resan 22, Nysosel 222 and 325, all with low activation energy, were more active than DM3 and G95H, which had higher activation energy. However, the less active catalysts increased the linoleate selectivity of soybean oil during hydrogenation. The yields of bothtrans isomers and winterized oil were higher for the more selectively hydrogenated oil catalyzed by the less active catalysts. In the sensory evaluation, the fractionated solid fat that contained moretrans isomers was lower in flavor scores than the fractionated liquid oil after hydrogenation and winterization of soybean oil.     

Nickel-catalyzed hydrogenation of soybean oil: I. Kinetic,equilibrium and mass transfer determinations

The kinetic and equilibrium constants were determined for the hydrogenation of soybean oil on a commercial nickel catalyst in a 300-ml Parr batch reactor. These constants were used to calculate the hydrogen gas absorption coefficients by coupling mass transfer with reaction rate based on a Langmuir Hinshelwood model. The activation energy for the rate-determining step was 23 kcal/g mol whereas the adsorption energy for hydrogen was −12.5 kcal/g mol. The gas absorption coefficients varied between 0.3 to 0.7 min⁻¹ as the temperature ranged between 140–180 C.     

Selective conjugation of soybean esters to increase hydrogenation selectivity

Polyunsaturated fatty acid methyl esters of soybean oil (MeSBO) were selectively conjugated as a means of increasing the linolenate selectivity of various homogeneous and heterogeneous hydrogenation catalysts. Kinetics of the conjugation reaction in various solvents indicated that linolenate conjugated 5–8 times faster than linoleate. Selective conjugation of MeSBO with potassiumt-butoxide in dipolar solvents resulted in an increase in linolenate hydrogenation selectivity to 7–8 with Ni and Pd heterogeneous catalysts, and to 7–10 with homogeneous and heterogeneous chromium carbonyl catalysts.Trans-unsaturation in the hydrogenated products was only 1–3% with the chromium carbonyl catalysts, in contrast to 30–39% with the heterogeneous metal catalysts. Triglycerides were readily converted to partial glycerides andt-butyl esters with the potassiumt-butoxide reagent. Presented at the AOCS North Central Section Symposium, March 1980.