Hydrogenation of Peanut and Sesame Oils in Hexane

The various parameters of hydrogenation of peanut and sesame oils in hexane have been investigated. At 140°C, 100 p. s. i. g. total pressure and 200 shakes/min. agitation the rate and selectivity of hydrogenation of peanut oil in hexane increased with increase in catalyst concentration from 0.1 to 0.3% Ni, beyond which (0.5 and 1.0%) the rate remained practically same and the selectivity decreased. The rate and selectivity decreased with decrease in total pressure of the system from 100 to 85 and 70 p. s. i. g. at 140°C and 0.3% Ni. The trans isomer formation was almost similar to that observed at 100 p. s. i. g. The reaction appeared to be of first order for certain period of hydrogenation at all catalyst concentrations. The temperature was the most important variable in controlling rate and selectivity. Both selectivity and the trans isomer formation increased from 115° to 140°C. These experiments demonstrated the commercial feasibility of the solvent (miscella) hydrogenation process.     

Synthesis and characterization of poly(ether‐block‐amide) membranes for the pervaporation of organic/aqueous mixtures

We made poly(ether‐block‐amide) membranes by casting a solution on a nonsolvent surface. The effects of the solvent ratio (n‐butanol/isopropyl alcohol), temperature, and polymer concentration on the quality of the membranes were studied. The results show that the film quality was enhanced with increasing isopropyl alcohol ratio in the solvent. This behavior was related to the reduction of the solution surface tension and the interfacial tension between the solution and nonsolvent. Uniform films were made at a temperature range of 70–80°C and a polymer concentration of 4–7 wt %. The morphology of the membranes was investigated with scanning electron microscopy. The qualities of the films improved with increasing isopropyl alcohol ratio in the solvent. With these membranes, the pervaporation of ethyl butyrate (ETB)/water and isopropyl alcohol/water mixtures was studied, and high separation performance was achieved. For ETB/water mixtures, with increasing ETB content, both the permeation flux and separation factor increased. However, for isopropyl alcohol/water mixtures, with increasing isopropyl alcohol content, the permeation flux increased, but the separation factor was diminished. Increasing temperature in a limited range resulted in a decreasing separation factor and an increasing permeation flux. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Solubility and phase separation of poly(L,D‐lactide) copolymers

In this study, the solubility and precipitation properties of medical‐grade stereocopolymers were investigated. The solubility of the polymers was tested with eight different organic solvents and four nonsolvents. The solubility of poly(L,D ‐lactide) stereocopolymers was highly dependent on the L /D ratio of the copolymer. The phase‐separation ability was tested by cloud‐point titration with a solvent and a nonsolvent. The solvent was in all cases dichloromethane, and the nonsolvents were n‐hexane, methanol, ethanol, and isopropyl alcohol. The results showed that n‐hexane was the most efficient nonsolvent. Methanol and ethanol showed quite similar precipitation properties. Isopropyl alcohol was the least efficient nonsolvent of those studied. Also, the L /D ratio of the copolymer had an effect on the precipitation properties. The precipitation happened most easily when the L content was high. The molecular weight of the copolymer had only a slight effect on the phase separation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Studies on kinetics of catalytic isomerization of methyl linoleate

Kinetics of isomerization of methyl linoleate are studied on ruthenium (5%) on carbon in the temperature range 200–270 C with different solvents. Some equilibrium experiments also are carried out with rhodium and ruthenium catalysts. The reactions taking place are isomerization, hydrogenation and polymerization. The activities and the selectivities are dependent on the nature of the solvent used. Highly protic solvents like methanol or isopropyl alcohol exhibited very high activity and selectivity for hydrogenation, whereas aprotic solvents like hexane or cyclohexane showed very high selectivities for isomerization reaction. The reaction kinetics were found to be further complicated by polymer formation at low solvent concentrations. The effects of temperature, solvent concentration, catalyst quantity and time of reaction also were investigated.     

A comparison of six solvents for the extraction of jojoba seed

Summary Data are presented which show the effects of different solvents on the yield and properties of liquid wax fromSimondsia chinensis (jojoba) and on the characteristics of the hydrogenated waxes obtained from the liquid waxes. Three reagent grade solvents, carbon tetrachloride, benzene, and isopropyl alcohol, and three commercial grade solvents, heptane, hexane, and tetrachloroethylene, were evaluated as extractants for the liquid wax from jojoba. Soxhlet-type of extractions were carried out under conditions in which the solvent was the only significant variable. Four of the solvents extracted essentially the same amount of material from the seed while isopropyl alcohol extracted significantly more material and tetrachloroethylene significantly less. Obviously the difficulties involved in separating the solids recovered from the isopropyl alcohol extraction preclude its use as the extracting solvent for jojoba wax. The density of the liquid waxes varies from 0.8631 to 0.8648; the waxes from the tetrachloroethylene and hexane extractions had the lowest value and the wax from isopropyl alcohol the highest. In each case, regardless of the solvent used, a precipitate developed in the liquid wax after it had been desolventized and stored for 7–10 days. Hydrogenation of clear fractions and precipitate containing fractions of these liquid waxes showed that the precipitate had no apparent effect upon the melting point or hardness of the resulting solid wax. Some of the liquid waxes required a longer hydrogenation time to attain an iodine value of about 1. At this iodine value all of the solid waxes had melting points between 66 and 68°C. Hardness values of all the solid waxes as measured by the Trionic hardness gauge were 90. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Plastic fats and margarines through fractionation,blending and interesterification of milk fat

Milk fat stearins and oleins were blended with high‐ and low‐melting natural fats to produce plastic fats, vanaspati substitute and confectionery fats. Margarines of improved nutritional value were also formulated. Fractionation was carried out using acetone, hexane, and isopropyl alcohol. The yield (wt‐%) of high‐melting stearin (HMS) from acetone and IPA was 13.0 ± 0.2 to 13.3 ± 0.1 after crystallization for 24 h at 20 °C. The melting point of the products was 49.0 ± 0.5 to 49.8 ± 0.6 °C. However, in hexane the yield of HMS was 12.2 ± 0.2% at 10 °C. The olein fractions were further fractionated at 10 °C from acetone and IPA, and at 0 °C from hexane, to obtain superoleins and low‐melting stearins (LMS). HMS fractions were blended with rice bran oil and cottonseed oil at the ratio 70 : 30 (wt/wt), and the superoleins were blended with sal fat and palm stearin at the ratios 40 : 60, 30 : 70 and 20 : 80 (wt/wt). The blends were interesterified (product melting point: 22.7 ± 0.04 to 39.3 ± 0.10 °C) chemically and enzymatically to prepare margarine. The penetration values (in 0.1 mm) of these margarines were noted to be 112 ± 1.52 to 145 ± 0.00.     

Reversible gelation of acrylonitrile–vinyl acetate copolymer solutions. II. Mechanical properties

Concentrated solutions of acrylonitrile polymers exhibit reversible gelation. The rate of gelation at 25°C. was determined for various solutions of an acrylonitrile copolymer containing 7.7% vinyl acetate in mixtures of dimethylacetamide (solvent) and water (nonsolvent) by measuring the shear modulus of the forming gel as a function of time. The mechanical properties were also measured on a series of gels formed by cooling solutions to ?78°C. It was found that both the rate of gelation at 25°C. and the modulus of gels formed at ?78°C. increase very rapidly as either the solids level of the solution of the water content of the solvent is increased. The gelation rate data wree correlated with the gel melting points of the gels. The results are discussed and compared with the analogous but limited data available for other systems.     

An Unexpected Pressure Effect in the Catalytic Hydrogenolysis of a Complex Benzyl Amine

The selective hydrogenolysis of a complex benzylamine containing a pyridone ring and aryl fluorides was investigated. The aim of the research was to find a catalyst and reaction conditions under which the complete hydrogenolysis of the benzylamine could be accomplished with no aryl fluoride cleavage nor pyridone hydrogenation observed. This objective was accomplished by use of a specific 10 % Pd/C catalyst in a THF/EtOH solvent at 40 °C. It was found that as the H₂ pressure decreased the amount of debenzylated amine increased because of the decrease in pyridone hydrogenation. Unexpectedly, though, the rate of hydrogenolysis also increased with decreasing H₂ pressure. A rationale for this observation is presented.

     

Ni-B非晶态合金催化加氢制备间甲苯胺

将自制的Ni-B非晶态合金催化剂用于间硝基甲苯催化加氢制备间甲苯胺的反应。考察了加氢条件对间甲苯胺产率的影响。结果表明,制得的Ni-B非晶态合金催化剂具有良好的催化活性;以乙醇为溶剂,催化剂与原料的质量比为1∶5,反应时间为2 h,反应压力为1 MPa,反应温度为100°C,此条件下间甲苯胺产率为99.8%。     

Alcohols as H-donor media in coal conversion. 1. Base-promoted H-donation to coal by isopropyl alcohol

Isopropyl alcohol can act as a hydrogen donor to coal, as can tetralin. In contrast to tetralin, however, the transfer of hydrogen by the alcohol can be promoted by the presence of either potassium isopropoxide or KOH. Acetone is formed from the alcohol in quantities that accord with the amounts of hydrogen transferred to the coal. In runs at 335 °C for 90 min, coal was converted with isopropyl alcohol in the presence of either the alkoxide or KOH to a fully pyridine-soluble product with $\text{H}\text{C}$ ratios from 0.88 to 1.13, in contrast to coal (0.79). The organic sulphur content of the coal was reduced from 2.1% to 1%. Model-compound studies with anthracene and diphenyl ether showed that the anthracene was reduced in the system to 9,10-dihydroanthracene, but the ether was recovered unchanged. The coal products from the alcohol/base treatment are very rich in aliphatic hydrogen and have number-average molecular weights in the 450–500 range. The scheme suggested to explain the conversion at 335 °C includes initial hydrogenation of anthracene-like structures in the coal, followed by thermolysis of the dihydro-intermediate.     

Investigation of the Hydrogenation of Some Substituted Alkylbenzenes in a Laboratory Scale Trickle-Bed Reactor

The liquid–phase hydrogenation kinetics of toluene, cumene and mesitylene was studied over an alumina-supported nickel catalyst in a laboratory scale trickle-bed reactor operating isothermally at temperature of 75–115°C and at hydrogen pressures of 20–40 bar. The experiments performed in the absence of intraparticular diffusion resistance showed that the catalyst deactivated rapidly at the initial stage of the experiment, after which a virtually stable level of the catalyst activity was attained. The systematic kinetic experiments carried out with a stable aged catalyst revealed that cumene and mesitylene at high concentrations retarded the hydrogenation rate, whereas such an effect was not observable for toluene. The results of the kinetic experiments were interpreted quantitatively with a reaction mechanism involving sequential addition of hydrogen to absorbed aromatic molecules.     

Alternative hydrocarbon solvents for cottonseed extraction

Hexane has been used for decades to extract edible oil from cottonseed. However, due to increased regulations affecting hexane because of the 1990 Clean Air Act and potential health risks, the oil-extraction industry urgently needs alternative hydrocarbon solvents to replace hexane. Five solvents,n-heptane, isohexane, neohexane, cyclohexane, and cylopentane, were compared with commercial hexane using a benchscale extractor. The extractions were done with a solvent to cottonseed flake ratio of 5.5 to 1 (w/w) and a miscella recycle flow rate of 36 mL/min/sq cm (9 gal/min/sq ft) at a temperature of 10 to 45°C below the boiling point of the solvent. After a 10-min single-stage extraction, commercial hexane removed 100% of the oil from the flakes at 55°C; heptane extracted 100% at 75°C and 95.9% at 55°C; isohexane extracted 93.1% at 45°C; while cyclopentane, cyclohexane, and neohexane removed 93.3, 89.4, and 89.6% at 35, 55, and 35°C, respectively. Each solvent removed gossypol from cottonseed flakes at a different rate, with cyclopentane being most and neohexane least effective. Based on the bench-scale extraction results and the availability of these candidate solvents, heptane and isohexane are the alternative hydrocarbon solvents most likely to replace hexane. Presented in part at the AOCS Annual Meeting & Expo, Atlanta, Georgia, May 1994.     

Phase investigations of fats. II. Systems containing oleic and stearic acids and an organic solvent

1. The ternary systems oleic acid-stearic acid-commercial hexane and oleic acid-stearic acid-acetone containing varying amounts of the three components have been equilibrated at 0°C., −10°C., −20°C., −30°C., and −40°C.
2. From compositional data of the liquid and solid phases in equilibrium at each isotherm, ternary phase diagrams have been constructed. From these diagrams it is possible to predict the degree of separation which can be obtained with any given mixture of oleic and stearic acids, using either acetone or commercial hexane as solvent.
3. With practical solvent ratios the phase diagrams at −20°C., −30°C., and −40°C., exhibit closed areas representing liquid phase composition. The liquid phase boundaries have been established for each isotherm investigated.
4. The intersolubilizing effect of oleic acid on stearic acid, greater in commercial hexane than in acetone, and the possible formation of mixed crystals of oleic and stearic acid have been noted.
5. Oleic acid of high purity can be obtained as one of the practical applications of these data.

     

Polymorphic behavior of high-melting glycerides from hydrogenated canola oil

Canola oil was hydrogenated with a commercial nickel catalyst at 175°C and 15 psi hydrogen pressure. Samples were taken during the reaction starting at 15 min and thereafter at ten-minute intervals. The reaction was stopped after two hours. The high-melting glycerides (HMG) were obtained by fractional crystallization at 15°C with acetone as solvent. The HMG were analyzed for fatty acid and triglyceride composition by gas liquid chromatography andtrans was determined by infrared spectroscopy. In the first 45 min of hydrogenation of canola oil, the 18:0 fatty acid increased at a low rate while thetrans fatty acid content increased at a much faster rate. The 16:0 and 18:0 content of the HMG was highest andtrans content the lowest during the period in which the triglyceride composition was the most diverse. The 54-carbon triglyceride content of the HMG increased from 64% to 78% during the two hours of hydrogenation. The short spacings for the HMG showed the presence ofβ crystals as well as several intermediate forms. The number of short-spacings increased with hydrogenation time. The differential scanning calorimetry (DSC) melting profile of the HMG showed one broad peak between 20 and 30°C and two peaks around 60°C and above. Crystallization temperatures of the HMG were in the range of 40–45°C. Presented at the 81st American Oil Chemists' Society Annual Meeting, April, 1990, Baltimore, Maryland.     

Low-temperature—long-time,high-temperature—short-time liquefaction of coal (Hokudai process): 2. Effect of reaction conditions

A vitrinite-rich Australian subbituminous coal (77 wt %) was subjected to two-stage hydrogenation (low-temperature-long-time, high-temperature-short-time) using several different catalysts with or without donor solvent and with the temperature range and time of the first hydrogenation stage varied. The condition used in the first stage did not significantly affect the final results of the hydrogenation and ≈ 30 wt % always remained as an undistillable fraction. The use of donor solvent or higher pressure improved the distillate yield and the use of active catalyst had a significant effect. In the best case (450 °C-60 min and 500 °C-20min, under 12 MPa initial hydrogen pressure, using Co-Mo catalyst) 54 wt % of oil boiling up to 325 °C and 68 wt % of total distillable oil boiling up to 500 °C were obtained.     

Studies on castor oil. II. Hydrogenation of castor oil

1. Products of low iodine value (<10.0) and hydroxyl value (35–40) can be readily obtained by hydrogenating castor oil at atmospheric pressure and at temperatures of the order of 220°, using 1.0% Raney nickel.
2. Dehydration of ricinoleic acid and subsequent hydrogenation of the resulting double bond as also simple saturation of ricinoleic acid are the main reactions occurring during the hydrogenation of castor oil under ordinary conditions.
3. Increase in the amount of catalyst favors more the hydrogenation of double bond at lower temperatures and both dehydration and hydrogenation at about 220°, which seems to be the optimum temperature for the maximum conversion of ricinoleic acid into nonhydroxy acids with both Raney and dryreduced nickel at atmospheric pressures.
4. Higher proportions of catalyst, addition of catalyst stepwise, and higher temperature of hydrogenation cause considerable splitting and estolide formation.
5. When hydrogenation is carried out at room temperature, under a pressure of 40 p.s.i. with alcohol as solvent, a product rich in monohydroxy stearic acid is obtained.
6. True unsaturation of hydrogenated castor oil is measured by the Wijs method at 15–20°C.

     

Effect of Supports on the Catalytic Hydrogenation of Polystyrene

The heterogeneous catalytic hydrogenation of polystyrene dissolved in cyclohexane over Pd-containing catalysts have been investigated in a batch reactor. Ultraviolet technique was employed to monitor the hydrogenation extent. The catalyst properties were modified by sol?Cgel methods. The effects of temperature and catalyst support were investigated over the ranges 500?C1,500?psig and 138 to 190?°C. In each case, fully saturated materials were obtained with no chain scission (i.e., degradation). The rate of hydrogenation showed strong dependence on the catalyst support.     

Hydrogenation and Isomerization of Methyl 9-Octadecenoates

Both methyl cis-9-octadecenoate and methyl trans-9-octadecenoate (commonly known as methyl oleate and methyl elaidate) were hydrogenated at operating conditions within the following ranges: 100–140°C, 1.7–14.6 at and 0.05–0.14% nickel catalyst. Correlations were developed for both geometrical and positional isomers as a function of iodine value. Decreases in pressure or increases in temperature resulted in a relatively greater increase in the amounts of positional isomers as compared to geometrical isomers. The rates of isomerization were found to vary between 0.7 to 2.5 times the rates of hydrogenation for hydrogenation runs with methyl cis-9-octadecenoate. The ratio between these two rates increased with higher temperatures or lower pressures. The rates of hydrogenation were compared for methyl cis-9-octadecenoate, methyl trans-9-octadecenoate, and cottonseed oil. Hydrogenation rate constants decreased in the following order: methyl trans-9-octadecenoate, methyl cis-9-octadecenoate, and cottonseed oil. The induction period that occurred only when a new catalyst was used depended on the temperature, pressure, and fatty feedstock being hydrogenated. The catalyst was activated to a considerable extent during the induction period.     

Hydrogenation of double bonds in olefin-modified starch

Catalytic hydrogenation of octadienyl-modified starch was performed with Rh complexes. The nature of solvent played a significant role as it has two distinct actions: swelling of the substrate and solubilization of the catalyst. Complete hydrogenation was performed with Rh/TPPTS-based catalyst at 40 °C and under 30 atm Hydrogen in H₂O/EtOH(50/10) mixture.     

An Unexpected Pressure Effect in the Catalytic Hydrogenolysis of a Complex Benzyl Amine

The selective hydrogenolysis of a complex benzylamine containing a pyridone ring and aryl fluorides was investigated. The aim of the research was to find a catalyst and reaction conditions under which the complete hydrogenolysis of the benzylamine could be accomplished with no aryl fluoride cleavage nor pyridone hydrogenation observed. This objective was accomplished by use of a specific 10 % Pd/C catalyst in a THF/EtOH solvent at 40 °C. It was found that as the H₂ pressure decreased the amount of debenzylated amine increased because of the decrease in pyridone hydrogenation. Unexpectedly, though, the rate of hydrogenolysis also increased with decreasing H₂ pressure. A rationale for this observation is presented.