πSynthesis and evaluation of a series of α-hydroxy ethers derived from isopropyl oleate

Several fatty derivatives with bulky moieties were prepared by treatment of epoxidized isopropyl oleate with a number of alcohols in the presence of sulfuric acid catalyst to provide a series of α-hydroxy ethers in good yield. The materials were analyzed for cold flow performance through cloud point and pour point determinations. The most promising α-hydroxy ether produced in this study, with respect to both low temperature behavior and economic criteria, was isopropyl 9(10)-(2-ethylhexoxy) 10(9)-hydroxystearate, which has a cloud point of −23°C and pour point of −24°C.     

Long term storage of soybean and cottonseed salad oils

Commercially prepared and packaged soybean and cottonseed salad oils from several different processors were evaluated periodically during storage for 12 months. Partially hydrogenated and winterized soybean oils, as well as unhydrogenated soybean salad oils, were stored in bottles and cans at 78 and 100 F. Control samples of all oils were held at 0 F during the entire test. Some lots in bottles and cans were packaged under nitrogen to improve storage stability. Agreement was good between organoleptic and oxidative evaluation of aged oils. After 26 weeks of storage at 100 F, the flavor of partially hydrogenated-winterized oils packaged under nitrogen showed a minimum loss. These same oils did not exhibit much, if any, reduction in their oxidative stability as indicated by storage peroxide values (active oxygen method). Soybean oil not protected with nitrogen demonstrated progressive flavor deterioration at 100 F. After 10 weeks of storage, the deterioration became marked and the flavor score was below 5. From limited observations, bottled oils appear to have a better stability than oils packaged in screw-cap tin cans. Hydrogenated oils packaged under nitrogen in cans had good oxidative stability, but some lowering of the flavor score was observed. Nonhydrogenated soybean oils packaged in tin cans not under nitrogen exhibited the most rapid flavor deterioration of all lots of oil investigated. Presented in part at the AOCS meeting, New York, October 1968 ARS, USDA     

Stereoisomere Aromastoffe

Zusammenfassung Die Synthese von acht verschiedenen 2-Alkoxy-5-alkyl-tetrahydrofuranen und ihren Stereoisomeren wird vorgestellt, sieben von ihnen sind als Aromastoffe der Wassermelone bekannt. Alle Stereoisomeren werden, ausgehend von optisch reinen-Nonalacton-Enantiomeren, synthetisiert und mit Diisobutylaluminiumhydrid selektiv zu den entsprechenden Lactolen reduziert. Die Lactole werden mit den gewünschten Alkoholen in schwach saurer Lösung zucis/trans-Diastereomeren umgesetzt und durch Flüssigchromatographie in optisch reine Stereoisomere getrennt. Die sensorische Charakteristik aller Stereoisomeren der sieben Verbindungen wird aufgezeigt. Die Trennung dercis/trans-Diastereomeren an DB-210 wird vorgestellt und die chirospezifische Differenzierung der acht Verbindungen diskutiert.

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Stereoisomeric flavour compounds L. Optically pure 2-alkoxy-5-alkyl-tetrahydrofurans — structures and properties

Summary The synthesis of eight different 2-alkoxy-5-alkyltetrahydrofurans and their stereoisomers is presented, seven of which are known to be flavour compounds of water melons. All stereoisomers were synthesized from optically pure-lactone enantiomers, which were selectively reduced by diisobutylaluminium hydride to the corresponding lactols. The lactols were treated with the desired alcohol component in weakly acidic media to yield thecis/trans diastereoisomers, which were separated into optically pure stereoisomers by liquid chromatography. The sensory characteristics of all four stereoisomers of the seven compounds are given. The Stereodifferentiation of thesecis/trans diastereoisomers on DB-210 is demonstrated and the direct chirospecific differentiation of all eight compounds discussed.

     

Production of Industrially Useful and Renewable p-Cymene by Catalytic Dehydration and Isomerization of Perillyl Alcohol

We report the dehydration and isomerization of renewable perillyl alcohol to industrially useful p-cymene in 91% yield utilizing 2.0 mol% para-toluenesulfonic acid (pTsOH) catalyst at 110 °C as a 3.0 M solution in toluene. Lower reaction temperatures, catalyst loadings, and/or starting concentrations resulted in lower yields of p-cymene as well as longer reaction times. Conversion of perillyl alcohol to p-cymene yielded atom and carbon economies of 88.1% and 100% as well as an E-factor of 2.7, thereby indicating that the process was both green and sustainable. A lower yield of 86% was observed when the reaction was performed neat, but a lower E-factor of 0.4 indicated that neat conditions were more desirable from an environmental perspective. Application of the optimized parameters to 3.0 M solutions of dl-limonene led predominantly to oligomerization (92%) as opposed to dehydroisomerization (5%), which was attributed to the strong Brønsted acidity of pTsOH. In addition, camphene (44%), terpinene isomers (15%), and limonene (14%) were obtained when dehydroisomerization was attempted on 3.0 M solutions of α- and β-pinene, which was once again attributed to the acidity of the catalyst. Oligomerization was strongly favored when dehydroisomerization of dl-limonene, α- and β-pinene was attempted neat. In summary, synthesis of renewable p-cymene was readily achieved from perillyl alcohol with catalytic pTsOH but competing side reactions suppressed yield when dehydroisomerization of dl-limonene, α- and β-pinene was attempted due to the strong Brønsted acidity of the catalyst.     

Tetranorsesquiterpenoids as Attractants of Yucca Moths to Yucca Flowers

Journal of Chemical Ecology - The obligate pollination mutualism between Yucca and yucca moths is a classical example of coevolution. Oviposition and active pollination by female yucca moths occur...     

Segmentation of the fascia lata and reproducible quantification of intermuscular adipose tissue (IMAT) of the thigh

Magnetic Resonance Materials in Physics, Biology and Medicine - To develop a precise semi-automated segmentation of the fascia lata (FL) of the thigh to quantify IMAT volume in T1w MR images and...     

Pb-Free solders: Part 1. Wettability testing of Sn−Ag−Cu alloys with Bi additions

Maximum bubble pressure, dilatometric, and meniscographic methods were used in the investigations of the surface tension, density, wetting time, wetting force, contact angle, and interfacial tension of liquid alloys of Sn−Ag−Cu eutectic composition with various additions of Bi. Density and surface tension measurements were conducted in the temperature range 250–900 °C. Surface tensions at 250 °C measured under a protective atmosphere of Ar−H₂ were combined with data from meniscographic studies done under air or with a protective flux. The meniscographic data with a nonwetted teflon substrate provided data on interfacial tension (solder-flux), surface tension in air, and meniscographic data with a Cu substrate allowed determinations of wetting time, wetting force, and calculation of contact angle. The calculated wetting angles from meniscographic studies for binary Sn−Ag eutectic and two ternary Sn−Ag−Cu alloys were verified by separate measurements by the sessile drop method under a protective atmosphere with a Cu substrate. Additions of Bi to both ternary alloys improve the wettability and move the parameters somewhat closer to those of traditional Sn−Pb solders.     

Pb-Free solders: Part II. Application of ADAMIS database in modeling of Sn−Ag−Cu alloys with Bi additions

The ADAMIS database was used for calculation of the surface tension of the quaternary Sn−Ag−Cu−Bi liquid alloys by Butler's model. The resultant data were compared with those from the maximum bubble pressure measurements from Part I. The same thermodynamic database was next applied for the calculation of various phase equilibria. It was established that the Bi addition to the ternary Sn−Ag−Cu alloys (Sn-2.6Ag-0.46Cu and Sn-3.13Ag-0.74Cu in at.%; Sn-2.56Ag-0.26 Cu and Sn-2.86Ag-O.40Cu in mass%) causes lowering of the melting temperature and the surface tension to make the tested alloys closer to, traditional Sn−Pb solders. The simulation of the solidification by Scheil's model showed that the alloys with the higher Bi concentration are characterized by the lifting-off failure due to the segregation of Bi at the solder/substrate boundary. Thus, in modeling of new Pb-free solders, a compromise among various properties should be taken into consideration.