Rapid isomerization of allylic alcohols with iridium(I) and rhodium(I) complexes at ambient temperature

Among allylic alcohols, but-3-en-2-ol is most rapidly isomerized to give butan-2-one in the presence of Ir(ClO₄)(CO)(PPh₃)₂ while 2-methylprop-2-en-1-ol most rapidly undergoes the isomerization to give 2-methylpropanal in the presence of Rh(ClO₄)(CO)(PPh₃)₂ at room temperature under hydrogen.     

American safflower seed oil

Summary The chemical and physical characteristics of a sample of hot pressed oil from saflower seed grown in Montana have been determined. This oil was found to contain 87.72 per cent of unsaturated acids, and 5.92 per cent of saturated acids. The composition of the oil has been determined with the following results, and, for comparison, results for sunflower seed and soy bean oils previously obtained, are also given. It will be observed that safflower oil contains a considerably larger proportion of linolic acid and less oleic acid than either of the other two oils, and this fact would account for its superior drying power.     

Hydrogenation of dienes with cationic rhodium complexes

Methylcis-9,cis-12-octadecadienoate (methyl linoleate;c9,c12), itst10,t12 andt10,c12 isomers and methylcis-9-octadecenoate (methyl oleate;c9) were hydrogenated with rhodium complexes, the active species of which consisted of [RhL₂]⁺ and [RhL₂H₂]⁺ with ligands L=P(C₂H₅)₂C₆H₅ (catalyst A) P(i-C₄H₉)₃ (catalyst B) and P(CH₃)₃ (catalyst C). Using these catalysts the influence of steric effects on the reaction mechanism of hydrogenation of dienes was studied. The reactions were carried out in 2-propanol at atmospheric hydrogen pressure and ambient temperature. During hydrogenation ofc9 on catalysts A and B, geometrical isomerization mainly occurred, whereas on catalyst C some positional isomerization also took place.C9,c12 was almost exclusively hydrogenated via conjugated intermediates on catalyst A. On catalyst C, one of the double bonds was hydrogenated directly, in most cases. In the absence of hydrogen, catalysts A and B conjugatedc9,c12 very fast. The conjugation activity of catalyst C was much lower. Catalyst C showed a high 1,5-shift activity for the conjugatedcis, trans andtrans, cis intermediates during hydrogenation, in contrast to catalysts A and B, which showed a poor activity in this respect.T10,t12 was hydrogenated almost exclusively via 1,4-addition of hydrogen to thecisoid conformation, whereas only a slight preference was found in this mechanism over 1,2-addition for the hydrogenation oft10,c12. On the sterically unhindered catalysts A and C thetrans double bond int10,c12 was preferentially hydrogenated whereas on catalyst B, with its bulky ligands, thecis double bond was reduced faster than thetrans double bond.     

Homogeneous hydrogenation of dienes with rhodium complexes

Different Rh complex catalysts were compared for the hydrogenation of methyl sorbate and linoleate in the absence of solvents. At 100 C and 1 atm H₂ the following complexes, RhCl(Ph₃ P)₃ (Ph= phenyl), [RhClNBD]₂ (NBD=norbornadiene) and RhH(CO)(Ph₃P)₃, produced mainly methyltrans-2-hexenoate (34 to 56%). Their diene selectivity was not particularly high as they produced 14 to 41% methyl hexanoate. With RhCl(Ph₃ P)₃ constant ratios between rates of methyl sorbate disappearance and formation of methyltrans-2- andtrans-3-hexenoate indicate approximately the same activation energy for 1,2-addition of H₂ on the Δ4 double bond of methyl sorbate and for 1,4-addition to this substrate. In the hydrogenation of methyl linoleate with RhCl(Ph₃ P)₃, the kinetic curves were simulated by a scheme in which 1,2-reduction was more than twice as important as 1,4-addition of H₂ via conjugated diene intermediates. Although the complexes RhCl(CO)(Ph₃ P)₃ and [Rh(NBD)(diphos)]⁺PF₆ (diphos=diphosphine) were inactive in the hydrogenation of methyl sorbate, they catalyzed the hydrogenation of methyl linoleate at 100 C and 1 atm. Catalyst inhibition apparently was caused by stronger complex formation with methyl sorbate than with the conjugated dienes formed from methyl linoleate.     

Oxidative stability of safflower oil

Oils from a number of varieties of safflower (Carthamus tinctorius L.) seeds (achene) were measured for oxidative stability by the gain in weight method. The induction periods of oils containing 75% to 80% linoleic acid ranged from 288 to 715 hr. Safflower oils containing 79% to 80% oleic acid and only 11% to 15% linoleic acid had induction periods ranging from 1274 to 2374 hr. No correlation between induction period and total tocopherol content was observed. However, there were indications that oils from pigmented seeds were less stable than oils from pigmentless seeds. Blending of an oil containing a high amount of linoleic acid with an oil containing a high amount of oleic acid gave a blend with an induction period intermediate between the two. However, the induction period was considerably less than the theoretical average calculated for the mixture. Arizona Agricultural Experiment Station Technical Paper No. 1389.     

New dicarbonyl-o-semiquinonato rhodium complexes

Two novel dicarbonyl rhodium complexes with 3,6-di-tert-butyl-o-semiquinones containing back bonded –OCH₃ and –F substituents were synthesized and characterized. The number of analogous dicarbonyl-o-semiquinonato rhodium complexes is discussed from the viewpoint of the phenomenon of “bending crystals”.     

Pilot-plant preparation of edible safflower oil

Summary Tests conducted on a pilot-plant scale with two lots of commercial, alkali-refined safflower oil demonstrate that no difficulty is experienced in producing a salad oil of good, initial quality with good flavor stability when stored at 60°C. in the dark. Although results indicate safflower oil is suitable for a salad oil, they should not be construed as indicating its stability as a cooking oil since tests of this type were not conducted. The addition of citric acid improved the oxidative stability of the oil, and citric acid plus propyl gallate gave even further improvement. No significant increase in flavor stability resulted from these additives. One of the divisions of the Agricultural Research Service, U. S. Department of Agriculture.     

Catalytic isomerization and dechlorination of nonenes

A heterogeneous gas/solid catalytic process for the simultaneous isomerization and dechlorination of nonenes has been identified. Several catalyst systems, including a variety of solid acids, are effective for these reactions. The catalytic isomerization reaction increases the relative level of isomers with higher reactivity towards aromatic alkylation. The dechlorination reaction involves elimination of HCl. The process has been applied to the reactivation and recycle of recovered nonenes from the AlCl₃-catalyzed alkylation of diphenylamine. The relative reactivites of the various proposed isomers towards alkylation of diphenylamine catalyzed by AlCl₃, and a mechanism for their redistribution in the recovered alkylate after catalytic re-isomerization are proposed.     

The role of safflower oil in edible oil applications

Safflower oil has been used as an edible oil in numerous countries for many years. In the US, commercial use of safflower oil as an edible product was noted in the 1950's and the use continues at progressively higher levels each year. One use of safflower oil in “dressing” type products is related to the natural cold resistance of the oil. Other applications include oil, margarine and some imitation dairy products. Additional development work has been done on other food products so that the scope of usage could be broadened if there should be increased demands for safflower oil. The susceptibility of safflower oil to oxidation has been minimized by improved processing and packaging. Further use of safflower oil appears to be dependent upon availability, pricing, good cold resistance and the role of polyunsaturates in the diet.     

Lipid-protein complexes from safflower expeller cake

Lipid-protein complexes were prepared from safflower prepress expeller cake, which contains about 18% oil and 17% protein, by grinding and extraction with aqueous alkali, then coprecipitation of oil and protein in the extract with acid. In the laboratory, using hammer mills or high-shear homogenizers, complexes were obtained containing up to 48% oil with 46% protein. In the pilot plant, the best extraction, using an attrition mill, yielded a complex contain-ing 44% oil and 47% protein. Phenolic glucosides, which contribute to the bitterness and cathartic activity in safflower meal, were removed during the process. Loaves of bread with 10% of the wheat flour replaced by safflower lipid-protein complexes had acceptable properties and contained 25-36% more protein than the controls.     

Catalytic hydrogenation of soybean oil with Rh(l) dihydride complexes as catalysts

Cationic rhodium(I) complexes of the type [NBD Rh L₂]⁺[C1O₄]⁻ (NBD = norbornadiene and L = diphenylphosphinoethane or triphenylphosphine) have been studied as catalysts for the hydrogenation of soybean oil. These catalysts give a good yield of products with cis-configuration. Indeed, hydrogenation could be performed under mild conditions (30 C, 1 atm hydrogen pressure) to an iodine value of 80 with not more than 12% oftrans monoenes and only 5% conjugated isomers formed. The results obtained are interpreted on the basis of the equilibrium H₂RhL _n ⁺ ⇌HRhL_n+H⁺. By the addition of acid (HClO₄ ) the bishydrido form of the catalyst could be studied. With this system only small amounts of trans monoenes were formed and no othertrans isomers could be detected. By the addition of a base such as triethylamine, the monohydridic form of the catalyst could be studied. In contrast to the bishydrido complex, this system gave large amounts oftrans monoenes, together withcis-trans andtrans-trans forms of the 18:2 acid. With both forms of the catalyst system, conjugated isomers were formed.     

First donor stabilized-phosphenium rhodium complexes

The coordination properties of a donor stabilized-phosphenium adduct have been examined in rhodium chemistry. The preparation as well as the characterization of the first examples of donor stabilized-phosphenium rhodium(I) complexes is reported in this paper. Indeed, mono- and di-cationic rhodium complexes were obtained in quantitative yield by the direct addition of this imidazolium P(III)-ligand to [RhCl(1,5-COD)]₂ in CH₂Cl₂ solution with a 1:1 P/Rh ratio under argon and 2:1 P/Rh ratio under CO atmosphere, respectively. Crystal structure of the bis-cationic donor stabilized-phosphenium rhodium(I) complex has been obtained from an acetone/pentane mixture. Its molecular structure has revealed a particular arrangement in which the chloride atom is sandwiched between both imidazolium rings as a result of the electrostatic attractive interactions between the electron-deficient heterocarbene moieties and the electron rich halide atom. On the other hand, the basicity of N-donor-phosphenium adducts has been evaluated by measure of the CO stretching frequency in one rhodium complex, and was found halfway between the phosphites and the strong π-acceptor phosphines.     

Fractionation of sesame and safflower oil fatty acids with urea

Summary The fatty acid compositions of sesame and safflower oils have been determined by two urea fractionation procedures. A simple cumulative urea fractionation procedure has been found to give results similar to those obtained by an urea adduct elution method.     

Rigid urethane foams from hydroxymethylated castor oil,safflower oil,oleic safflower oil,and polyol esters of castor acids

Castor, safflower, and oleic safflower oil derivatives with enhanced reactivity and hydroxyl group content were prepared by hydroformylation with a rhodium-triphenylphosphine catalyst, followed by hydrogenation. Rigid urethane foams prepared from these hydroxymethylated derivatives had excellent compressive strengths, closed cell contents, and dimensional stability. Best properties were obtained from hydroxymethylated polyol esters of castor acids.     

Microwave-assisted catalytic transfer hydrogenation of safflower oil

Catalytic transfer hydrogenation (CTH) of safflower oil was studied using aqueous ammonium formate as hydrogen donor and palladium on carbon as catalyst in a closed vessel under controlled microwave irradiation conditions. The method offered good selectivity in complete reduction of linoleic acid to monounsaturated acid with a slight increase in stearic acid compared to other reported catalytic transfer hydrogenation methods. Selectivity was achieved by using microwave-assisted CTH without employing an emulsifier or high ratios of water to oil.     

Development and commercialization of GLA safflower oil

GLA safflower oil is a new commercial source of gamma‐linolenic acid (GLA), an important dietary omega‐6 fatty acid with properties similar and complementary to those of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In its native form, GLA safflower oil contains 60–70+% GLA. It is one of the first dietary supplements developed using modern biotechnology methods and is the first of a new generation of genetically modified (GM) plant oil ingredients developed solely for improvement of human health and nutrition.     

Diels-Alder adducts from safflower oil fatty acids

Methyl esters of alkali-isomerized safflower oil fatty acids after elaidinization with sulfur were treated with styrene in the presence of hydroquinone, with or without solvents. A combination of column chromatography and gas liquid chromatography techniques was employed for the estimation of the methyl esters of unreacted fatty acids, Diels-Alder adduct and polymers in the reaction products. Maximum yield of the Diels-Alder adduct (26.6%) was obtained when the elaidinized methyl esters of the fatty acids were treated with 1.5 moles of styrene per mole of linoleic acid in safflower oil fatty acids at 200–210 C for 6 hr. The methyl ester of the adduct was isolated in about 90% purity from the reaction product by vacuum distillation followed by solvent fractionation. The butyl ester of the adduct and the epoxy derivative of the methyl ester adduct were prepared and characterized.     

Some chemical processes utilizing oleic safflower oil

Oleic safflower seed (UC-1) produces an oil containing approximately 80% oleic acid and 12% linoleic acid. The oil is a source of high quality oleic acid, and fatty acids from the oil may be used without further separation in some applications where technical oleic acid is now used, since oleic safflower free fatty acids have a a higher oleic acid content than good commercial grades of oleic acid. A high purity oleic acid can be produced by urea fractionation. Ozonization of the oil followed by reductive cleavage yields pelargonaldehyde and nearly colorless aldehyde oils. Ozonization of a crude mixture of oleic safflower acids followed by oxidative cleavage provides high yields of azelaic acid and pelargonic acid. In contrast, ozonization of free fatty acids from polyunsaturated vegetable oils produces azelaic acid and mixtures of lower molecular weight carboxylic acids with smaller amounts of pelargonic acid. Furtherore, ozone consumption is lower and reaction time is shorter when oleic safflower acids are used in place of more highly unsaturated fatty acids.     

多孔WC-TiC催化剂的戊烷异构化活性

以TiC和MoSi₂为基体,WO₃和仲钨酸铵为WC的前驱体,碳酸氢铵为造孔剂,采用固相合成技术, 1 560 ℃制备碳化钛基复合WC催化材料。分别通过X射线衍射仪、扫描电镜、压汞仪、气相色谱和气质谱表征催化材料的相组成、显微结构、孔径分布和对戊烷的催化性能。结果表明,碳化钛基复合WC材料的相组成为TiC、SiC、MoC、 WC 和 (Ti, Si)C;当WO₃为WC前驱体时,催化材料的孔径呈现单峰分布［（0.3~50 μm）］,350 ℃其对戊烷的转化率为16.21%,异构化选择性为5.68%;当仲钨酸铵为WC前驱体时,催化材料的孔径呈现双峰分布［（100~800） nm和（1 ~5） μm］,WC颗粒在500 nm以下,350 ℃戊烷转化率达到48.44%,异戊烷的选择性为12.91%。     

Catalytic skeletal isomerization of linear butenes to isobutene

The increased demand for isobutene, used for the production of the octane-enhancer methyl tert-butyl ether, has generated tremendous interest in the catalytic conversion of the linear butenes to isobutene. In this review we survey the progress made since the late 1970s in implementing the catalytic skeletal isomerization reaction of these linear alkenes. Halogenated catalysts, especially those based on alumina, and prepared using a variety of compounds of fluorine, chlorine or bromine, have been shown to exhibit both high conversions and selectivities for the reaction, resulting in high yields of isobutene, when water is added to the feed stream. Elution of the halogen from the catalyst leads to the loss of catalytic activity and necessitates the continuous or discontinuous addition of the halogen compound. As a consequence, environmental and other considerations are most likely to weigh against the industrial usage of these catalysts. Another class of catalysts exhibiting high activities and selectivities, again in the presence of water, are the silicated aluminas. No information is, however, available on their long-term stability. Even alumina on its own displays high activity and selectivity, provided water is co-fed with the hydrocarbon stream. More recent results obtained over other types of catalysts such as zeolites and molecular sieves are also presented. Most promising are the results obtained with the zeolite ferrierite which gives high yields of the branched isomer in the absence of any other additive or diluent. The catalyst also appears to be fairly stable showing no decrease in the yield of isobutene after 14 days on-stream. The high yields of isobutene can be ascribed to the small channel diameters which prevent the extensive dimerization or oligomerization of the linear butenes or of the product isobutene. Plans for the first large-scale demonstration plant to produce isobutene from n-butenes using ferrierite as catalyst have already been announced in the United States.