Continuous ultrasonic hydrogenation of soybean oil. II. Operating conditions and oil quality

In previous work we found that ultrasonic energy greatly enhanced the rate of hydrogenation of soybean oil. We have now investigated parameters of ultrasonic hydrogenation and the quality of the resulting products. Refined and bleached soybean oil was hydrogenated continuously with and without ultrasonic energy at different temperatures, pressures and catalyst concentrations. Flavor and oxidative stability of the oils were compared with a commercially hydrogenated soybean oil. The extent of hydrogenation (ΔIV) was not affected by temperature between 245 and 290 C, but was greater at 106 psig than at 65 psig hydrogen pressure. The ΔIV of hydrogenated oils increased linearly with catalyst concentration from 40 ppm to 150 ppm nickel. At the same catalyst concentration the IV drop was significantly increased when ultrasonic energy was used. By reducing the amount of power supplied to the ultrasonic reactor to 40% of full power, the specific power (watts/ΔIV) was lowered by 60%. Linolenate selectivities and specific isomerization (%trans/ΔIV) remained the same, but linoleate selectivities were lower than for batch hydrogenation under varied operating parameters. Flavor scores were not significantly different, initially or after storage eight days at 60 C, for oils continuously hydrogenated with and without ultrasonic energy. Hydrogenation of soybean oil with ultrasonic energy offers a method to produce good quality products at potentially lower cost than present methods.     

Erfahrungen bei der Hydrierung von einigen Ölen und Fetten mit einem Kupferkatalysator

Experiences on the Hydrogenation of Fats with a Copper Catalyst Soybean oil, rapeseed oil and lard were hydrogenated using a copper catalyst. The products of hydrogenation were refined after the removal of copper following a new technique. The aforesaid oils were also hydrogenated with a nickel catalyst to the same iodine value and then refined. The products of hydrogenation using copper showed a better stability towards oxidation than those obtained with nickel.     

Anchored Wilkinson Catalyst: Hydrogenation of β Pinene

The hydrogenation of β pinene over homogeneous and anchored Wilkinson’s catalysts was studied. Phosphotungstic acid was used to anchor the Wilkinson catalyst to an alumina support by an interaction between the heteropoly acid and the rhodium atom of the complex. The hydrogenation of β pinene over the anchored catalyst was accompanied by some isomerization to α-pinene which was subsequently hydrogenated along with the β pinene to the pinanes with selectivities to the cis (endo) pinane in the 85–88 % range at near 100 % conversion. With the homogeneous Wilkinson catalyst an 88 % selectivity to cis pinane was also observed but only at 82 % conversion. The use of a 1 % Rh/Al₂O₃ catalyst for this hydrogenation gave some unexpected results. There was a facile isomerization to α pinene which was not hydrogenated further. The reaction stopped at about 30 % conversion at which time the cis and trans pinanes were present in near equal amounts in about 16–18 % yields.     

喹啉及其衍生物氢化还原技术进展

喹啉氢化衍生物具有多种生物活性,在染料、药物、杀虫剂和抗氧化剂合成设计与制造等方面有着广泛的应用。本文综述了喹啉及其衍生物的催化加氢、化学还原和氢转移加氢三种还原技术进展,同时也研究了喹啉环上不同取代基对氢化产物的影响。     

Anchored Wilkinson Catalyst: Hydrogenation of β Pinene

The hydrogenation of β pinene over homogeneous and anchored Wilkinson’s catalysts was studied. Phosphotungstic acid was used to anchor the Wilkinson catalyst to an alumina support by an interaction between the heteropoly acid and the rhodium atom of the complex. The hydrogenation of β pinene over the anchored catalyst was accompanied by some isomerization to α-pinene which was subsequently hydrogenated along with the β pinene to the pinanes with selectivities to the cis (endo) pinane in the 85–88 % range at near 100 % conversion. With the homogeneous Wilkinson catalyst an 88 % selectivity to cis pinane was also observed but only at 82 % conversion. The use of a 1 % Rh/Al₂O₃ catalyst for this hydrogenation gave some unexpected results. There was a facile isomerization to α pinene which was not hydrogenated further. The reaction stopped at about 30 % conversion at which time the cis and trans pinanes were present in near equal amounts in about 16–18 % yields.

     

Parallel hydrogenation of 2,2‐dimethylol‐1‐butanal and formaldehyde over supported NiCr and CuCr catalysts

The hydrogenation kinetics of 2,2‐dimethylol‐1‐butanal (TMP‐aldol) and formaldehyde were studied over two commercial supported catalysts; NiCr on silica and CuCr on alumina. Both catalysts hydrogenated the aldol selectively to triol, but the kinetic trends differed widely. With the nickel catalyst, the aldol hydrogenation was not started before almost all of the formaldehyde was consumed from the bulk phase, whereas the copper‐containing catalyst hydrogenated aldol and formaldehyde in parallel. Rate equations for the hydrogenation of aldol and formaldehyde were derived from a competitive surface mechanism. Since formaldehyde retarded significantly the hydrogenation rate of aldol over NiCr, the kinetic model was modified in order to take into account the inhibitory effect of formaldehyde. With the modified model, the experimental data produced over the NiCr catalyst were rather well described. The data from the experiments over the CuCr catalyst followed pseudo‐first order kinetics remarkably well. Furthermore, the kinetic model without the inhibitory effect of formaldehyde was able to describe the governing trends of the data obtained over the CuCr catalyst. © 2002 Society of Chemical Industry     

氢化松香制备与应用

介绍了松香催化加氢制备氢化松香的国内外发展概况,对其生产工艺、加氢催化剂、氢化松香化学成分的分析、松香催化加氢方法进行了综述,指出传统的氢化松香生产成本高的原因是采用贵金属Pd/C为催化剂,而降低氢化松香生产成本的有效途径是寻求一种非贵金属催化剂,并介绍了以Rany—Ni为催化剂制备氧化松香的方法,该方法不仅降低了氢化松香的生产成本,还提高了产品的质量。介绍了氢化松香在电子、食品、造纸、涂料、医药及合成橡胶等工业领域的应用状况。     

Über den Verlauf der Hydrierung von Triolein an Raney-Nickel

The Course of Hydrogenation of Triolein on Raney Nickel Triolein was dissolved in hexane and hydrogenated at room temperature and atmospheric pressure with Raney Nickel as catalyst. In a number of experiments the percentage of various hydrogenation products was compared with the theoretical values which might be obtained by the possible courses of reaction. It was found out that under currently employed experimental conditions triolein, diolein and monoolein are hydrogenated at the same rate. The direct hydrogenation of triolein to monoolein and tristearin, and of diolein to tristearin partly took place, especially when a highly active catalyst was employed. No difference was observed between the rates of hydrogenation of the fatty acid rests in the α- and β-positions.     

Ruthenium-supported catalysts for the stereoselective hydrogenation of paracetamol to 4-trans-acetamidocyclohexanol: effect of support,metal precursor,and solvent

The influence of the support, the metal precursor, and the solvent on the selective hydrogenation of paracetamol (4-acetamidophenol) was studied over supported ruthenium catalysts. The catalysts supported on the oxidic supports Al₂O₃ and SiO₂ gave the best results in terms of activity, selectivity for the acetamidocyclohexanols (99%), and stereoselectivity for the trans isomer (53 and 46%, respectively). Carbon-supported catalysts produced larger amounts of secondary compounds, mainly N-cyclohexylacetamide, which was derived from the hydrogenolysis reaction of the OH group. The use of a chloride precursor resulted in the enhancement of the formation of N-cyclohexylacetamide and partially hydrogenated products; the stereoselectivity also increased. Moreover, because of the acidity caused by residual Cl, condensation led to oligomers of paracetamol. In spite of the decrease in the selectivity for cyclohexanol derivatives when the more polar solvent ethanol was used instead of isopropanol or tetrahydrofuran the stereoselectivity for the trans isomer increased from 30 to 38%.The results confirm that the factors studied affect the mode of adsorption of the molecule of paracetamol on the catalyst in different ways. These effects determine the product distribution and the selectivity of the reaction.     

苯乙烯类热塑性弹性体的氢化

本文简介了氢化苯乙烯类热塑性弹性体基础聚合物的类型及其结构等因素对氢化产物物性的影响;对加氢催化剂和反应器的类型,加氢后催化剂的脱除,以及氢化SBS的生产,应用和消耗情况作了概述。     

Hydrogenation of the inertinite macerals of Bayswater coal

Yields of products from the hydrogenation of the inertinite and vitrinite+exinite macerals of the Bayswater (New South Wales, Australia) coal in a batch autoclave were investigated. Samples were hydrogenated for 1 h at 400 and 450 °C with tetralin as vehicle, hydrogen as charge gas and no added catalyst. The results show that the inertinite macerals contributed significantly to the liquid hydrogenation products, in particular to the oil yield obtained at 450 °C.     

Homogeneous catalytic hydrogenation of unsaturated fats: Cobalt carbonyl

Homogeneous hydrogenation of unsaturated fats by cobalt carbonyl has been compared with the previously reported catalysis by iron carbonyl. Soybean methyl esters, methyl linoleate and linolenate have been hydrogenated at 75–180C, 250–3,000 psi H₂ and 0.02 molar concn of catalyst. The cobalt carbonyl catalyst is more active at lower temp than iron carbonyl. The partially reduced products are similar to those observed with iron carbonyl, but the reaction differs in showing much less accumulation of conjugated dienes, no selectivity toward linolenate, almost complete absence of monoene hydrogenation to saturates, less double bond migration and moretrans isomerization. No evidence was found for a stable complex between cobalt carbonyl and unsaturated fats as previously observed with iron carbonyl. The rates of hydrogenation/double bond were the same for linoleate and linolenate on one hand, and for alkali-conjugated linoleate and nonconjugated linoleate on the other. Presented at AOCS Meeting in Minneapolis, 1963. A laboratory of the No. Utiliz. Res. & Dev. Div., ARS, USDA.     

均匀设计优化硒催化氢化丁腈橡胶乳液的研究

以硒粉为催化剂,水合肼和过氧化氢为氧化还原引发体系,进行了常温常压下的丁腈橡胶乳液加氢反应,采用均匀设计法研究了水合肼用量、硒粉用量、过氧化氢用量、二酰亚胺凝胶抑制剂用量、反应温度以及反应时间等对丁腈橡胶氢化度的影响,并利用红外光谱对氢化产物进行了表征.实验结果表明,在适宜的反应条件下,可制得氢化度为90％的氢化丁腈橡...     

Catalytic Oxidation and Reduction of Polycyclic Aromatic Hydrocarbons (PAHs) Present as Mixtures in Hydrothermal Media

The reactivity of fluorene, anthracene, and fluoranthene under oxidation and reduction conditions were investigated in this study. This project looks at catalytic and green approaches of converting PAHs to less toxic and/or less stable derivatives that are amenable to further degradation. Hydrothermal reactions have been performed at 300°C with pure H₂O and Nafion-SiO₂ catalyst for oxidation, and pure H₂O, HCOOH, Pd-C, and Nafion-SiO₂ catalysts for reductive hydrogenation. Time series has been performed for both the oxidation and hydrogenation systems. The products of the reaction were identified and quantified by the use of Gas Chromatography-Mass Spectrometry and the NIST Library. The reaction products include oxidized products of anthracene and fluorene; and hydrogenated derivatives of anthracene and fluoranthene. Fluoranthene did not undergo oxidation, and fluorene did not undergo hydrogenation under the conditions of this research.     

Stationary catalysts for the continuous hydrogenation of fats

Hydrogenation characteristics of a wide variety of stationary catalysts were studied with an aim to explore their possible use in the continuous hydrogenation of fats. Refined soybean oil was hydrogenated continuously in a vertical flow-through reactor over a fixed bed of catalyst. Catalysts investigated were pelleted products containing Raney nickel, reduced nickel, reduced palladium, and copper chromite, as well as granulated alloys of the Raney type, such as Ni-Al, Cu-Al, Pd-Al, and Cu-Cr-Al, which were activated with alkali. These catalysts offered a wide choice of activity, selectivity, and ability to form geometrical isomers. Pelleted copper chromite and granular Raney copper-chromium were found to be highly selective toward the linolenate moiety of soybean oil, whereas pelleted palladium on carrier, as well as granular Raney nickel, Raney copper, and Raney palladium, though moderately selective, exhibited very high activity even at relatively low temperatures. A unique feature of most of the stationary catalysts was the remarkably high rate of hydrogenation. With most catalysts, the iodine value of soybean oil was reduced by 40–60 units within a reaction period of 2–4 min. The hydrogenated fat was practically free of catalyst particles.     

Diimide hydrogenation of natural rubber latex

Hydrogenation is one important method of chemical modification, which improves the physical, chemical and thermal properties of diene‐based elastomers. Natural rubber latex (NRL) could be hydrogenated to a strictly alternating ethylene‐propylene copolymer using a diimide reduction system. The diimide reduction technique of NRL was accomplished by using hydrazine hydrate/hydrogen peroxide and Cu²⁺ as catalyst. The hydrogenated products are characterized by FTIR and NMR spectroscopy. It has been found that cupric acetate is a highly active catalyst for the reaction and the addition of a controlled amount of gelatin demonstrated a beneficial effect on the degree of hydrogenation, whereas, sodium dodecyl sulfate (SDS) acted as a stabilizer of the latex particle in the reaction system and reduced the degree of hydrogenation. In the presence of SDS, a longer reaction time and a higher amount of hydrazine hydrate was required for hydrogenation of NRL. Gel formation during hydrogenation does not significantly affect the degree of hydrogenation. Gel inhibitors such as hydroquinone also decrease the degree of hydrogenation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Hydrogenation and neutralization of carboxylic styrene–butadiene latex to form thermoplastic elastomer with excellent thermooxidation resistance

Hydrogenation of carboxylic styrene–butadiene rubber latex was carried out using hydrazine and hydrogen peroxide with ferrous sulfate as a catalyst without pressurized hydrogen and an organic solvent. A mixed inhibitor was used during hydrogenation to prevent gel formation. Various hydrogenation conditions were studied. Ferrous sulfate is better than is cupric sulfate as a catalyst. The hydrogenation degree can reach over 90%. The hydrogenated product was characterized by IR and DSC. The hydrogenated products behave as a thermoplastic elastomer with excellent thermooxidation resistance, due to the absence of most double bonds and the presence of crystalline domains of polyethylene segments formed by the hydrogenation of polybutadiene segments. Ionomers were obtained by neutralization of the hydrogenated product with metallic ions and characterized by IR, DSC, and TEM. The ionomers also behave as thermoplastic elastomers with mechanical properties better than those of the hydrogenated product without neutralization, due to the existence of ionic domains besides the crystalline domains. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1375–1384, 2002     

Flavor and oxidative stability of continuously hydrogenated soybean oils

Soybean oil was partially hydrogenated in a continuous system with copper and nickel catalysts. The hydrogenated products were evaluated for flavor and oxidative stability. Processing conditions were varied to produce oils of linolenate contents between 0.4 and 2.7%, as follows: oil flow, 0.6–2.2 liters/hr; reaction temperature, 180–220 C; hydrogen pressure, 100–525 psig, and catalyst concentration, 0.5–1% copper catalyst or 0.1% nickel catalyst.Trans unsaturation varied from 8 to 20% with copper catalyst and from 15.0 to 27% with nickel catalyst. Linolenate selectivity was 9 with copper catalyst and 2 with nickel catalyst. Flavor evaluation of finished oils containing 0.01% citric acid (CA), appraised initially and after accelerated storage at 60 C, showed no significant difference between hydrogenated oils and nonhydrogenated oil. However, peroxide values and oxidative stability showed that hydrogenated oils were more stable than the unhydrogenated oil. CA+TBHQ (tertiary butylhydroquinone) significantly improved the oxidative stability of test oils over oils with CA only, but flavor scores showed no improvement. Dimethylpolysiloxane (MS) had no effect on either flavor or oxidative stability of the oils.     

离子液体中催化香茅醛一锅合成薄荷醇

研究制备了Cu/ZrO2-SiO2双载体催化剂,并在离子液体介质中研究香茅醛催化加氢合成薄荷醇反应。结果表明：离子液体中的阳离子与香茅醛分子中的羰基形成氢键,使香茅醛更容易异构化为胡异薄荷醇,提高了催化剂选择性;特别是可调节酸度的[bmim][AlmCln]离子液体,有效提供香茅醛的异构化所需的路易斯酸条件,在竞争性加...     

Continuous slurry hydrogenation of soybean oil with nickel catalysts

Soybean oil was hydrogenated continuously in the presence of nickel catalysts. The iodine value of the products was varied by changing the oil flow rate and temperature of the reaction. Sulfur-promoted nickel catalyst increased the selectivity for linolenate hydrogenation, but formed much higher proportions oftrans isomers. Linoleate selectivity improved with temperature with both nickel and sulfur-promoted nickel catalysts, buttrans isomerization also increased. The feasibility of this continuous reactor system was demonstrated as a practical means to prepare hydrogenated stocks of desired composition and physical characteristics at high throughput.