bluuebunny/crossref_metadata_2025 huggingface dataset:
Mathematisches Modell und Lösung für die Schmierfilmdicke bei elastohydrodynamischem Kugelkontakt
Authors: Weber C. , Adams E.
Published: June 2007

Die durch O. Reynolds (1886) begründete klassische hydrodynamische Schmiertheorie führt u. a. im Fall der hier behandelten Punktberührung auf ein nicht akzeptables Ergebnis: Die durch Kapitza [10] angegebene Lösung für den Fall des Kugelkontaktes liefert das Verschwinden des Integrals über die Druckverteilung und damit auch der Traglast. Es wird hier gezeigt, daß diese Lösung eindeutig ist. Entgegen experimentellen Beobachtungen [20] ergibt die elastohydrodynamische Behandlung des Problems in [2] und in [3] negative Drucke mit nicht vernachlässigbar kleinem Betrag auf der Abströmseite. Dieser Mangel wird hier durch eine physikalisch begründete Abänderung des Freigliedes der Reynoldsschen Gleichung vermieden. Das dabei benutzte mathematische Modell beschreibt die elastische Verformung näherungsweise durch Annahme eines kreisförmigen Hertzschen Spaltes konstanter Filmdicke h0, außerhalb dessen die beiden festen Kugeln unverformt sind. Damit wird die Druckverteilung im inkompressiblen isothermen Schmierfilm überwiegend explizit sowie mit Fehlerabschätzung einer Differenzenlösung bestimmt. Durch Übergang zur Grenze großer Lasten ergibt sich hieraus die Parameterabhängigkeit von h0 in größerer Allgemeinheit als in [2] oder in [3].
Über die Lösbarkeit der Feldgleichungen des Zweiflüssigkeitsmodells für ein staubbeladenes Gas
Authors: Förste J.
Published: June 2007

Die Strömung eines staubigen Gases in einem beschränkten räumlichen Gebiet wird durch das Zweiflüssigkeitsmodell beschrieben. Mit Hilfe eines Iterationsverfahrens wird gezeigt, daß es ein Zeitintervall gibt, dessen Länge von den Anfangs‐werten der Geschwindigkeiten und der Dichtegradienten und den äußeren Kräften abhängt, in dem die Feldgleichungen lösbar sind. Es wird bewiesen, daß diese Lösung eindeutig bestimmt ist.
Lösung inkonsistenter linearer Gleichungssysteme und Bestimmung einer Pseudoinversen für rechteckige Matrizen durch Spaltenapproximation
Authors: Maess Gerhard , Peters Wolfgang
Published: June 2007

Die auf Kiesewetter und Albrand zurückgehende Methode der Spaltenapproximation, eine Variante der von Householder und Bauer untersuchten Klasse von Projektionsverfahren, eignet sich zur iterativen Lösung über‐und unter‐bestimmter linearer Gleichungssysteme. Sie führt die Lösung großer Systeme auf die wiederholte Lösung kleiner Teilsysteme zurück, ist also auch anwendbar, wenn die Koeffizientenmatrix zu groß für den Kernspeicher der Rechenanlage ist. In der vorliegenden Arbeit wird das Verfahren im Fall inkonsistenter Gleichungssysteme analysiert. Die Näherungen konvergieren gegen eine Pseudolösung, die beste Approximation im Sinne der Methode der kleinsten Quadrate ist. Mit Hilfe einer verallgemeinerten Inversen ((1, 2, 3)‐Inversen) X der Ausgangsmatrix kann die allgemeine Lösung bzw. Pseudolösung explizit angegeben werden. Hat die Ausgangsmatrix maximalen Spaltenrang, so ist X identisch mit der Moore‐Penroseschen Pseudoinversen A+, und mit dem Startvektor x= o konvergiert die Iteration gegen die normkleinste Lösung bzw. Pseudolösung A+b.
P‐Boundedness of Inverses of Nonlinear Operators
Authors: Bohl Erich
Published: June 2007

The central result of this paper reads as follows: Let T be a P‐bounded operator on a linear distance space. If I — P has a monotone inverse then I — T has a (I — P)−1‐bounded inverse. This Theorem is being applied to various special situations (e.g. nonlinear systems, nonlinear ordinary differential operators) to yield known and new results.
Existenz und Eindeutigkeit eines linearen hyperbolischen Anfangs‐Randwertproblems und die praktische Anwendung auf Probleme aus der Hydraulik. Teil I: Zur Existenz und Eindeutigkeit des linearen hyperbolischen Anfangs‐Randwertproblems
Authors: Iben H. ‐K.
Published: June 2007

For a linear hyperbolic mixed boundary value problem frequently occurring in the engineering science, the existence and uniqueness of a solution are proved. The complete, self‐contained and analytical solution of the problem are explicitly given. With a view to a correct indication of the problem, only such boundary conditions are permitted which are not in contradiction with the defined compatibility conditions.
Zur Konvergenzbeschleunigung bei Summen strikt kontraktiver Operatoren
Authors: Schneider K. R.
Published: June 2007

Let T1 and T2 be strictly contractive operators whose Lipschitz constants satisfy the relation x1 + x2 < 1. The aim of the paper is to give conditions under which there exist iteration procedures whose speed of convergence is higher than that one of the usual procedure (*) xn = T1xn‐1 + T2xn‐1 and whose complexity (expense of computer time) is less than that one of (*).
A Parabolic Control Problem with a Boundary Condition of the Stefan‐Boltzmann Type
Authors: Sachs Ekkehard
Published: June 2007

In this paper we consider a one‐dimensional nonlinear boundary control problem occuring in heat conduction with a boundary condition governed by the Stefan‐Boltzmann law. For L∞‐inputs we prove the existence and uniqueness of non‐negative solutions. Furthermore we show for a class of cost functionals that there exist optimal controls. We also give necessary conditions for optimal controls in form of a certain type of bang‐bang‐principle.
Zur Theorie des dynamischen Verhaltens von elastisch‐plastischen Körpern
Authors: Gröger K.
Published: June 2007

In this paper it is shown that under certain assumptions the dynamic behaviour of elastic‐plastic materials can be described by initial value problems for second order differential inequalities. In the case of a special constitutive relation the unique solvability of such problems is proved.
Magnetohydrodynamic Stability of Boundary Layers along a Flat Plate in the Presence of a Transverse Magnetic Field
Authors: Watanabe T.
Published: June 2007

The purpose of the paper is to consider theoretically first the behavior of two‐dimensional steady laminar boundary layer flow of an incompressible, electrically conducting fluid past a semi‐infinite flat plate in the presence of a transverse magnetic field by using the difference‐differential method. The neutral stability curves for wavelike disturbances of Tollmien‐Schlichting type are then presented for the velocity profiles obtained above in the wide range of magnetic parameter (mx). The results show that the skin friction and the critical Reynolds number decrease with increasing mx, so that the MHD boundary layer becomes less stable.
Creep Transition in Thick‐Walled Cylinder under Internal Pressure
Authors: Gupta S. K. , Dharmani R. L.
Published: June 2007

Transitional stresses for thick‐walled cylinder under internal pressure for the three stages of creep has been derived. For stationary stage of creep, the stresses and the assumed stress‐strain rate relations are the same as those given by Bailey, Odquist and others.
Über die Grundgleichungen der Plasmadynamik auf der Basis der Zweiflüssigkeitstheorie
Authors: Förste J.
Published: June 2007

Für die linearisierten Bewegungsgleichungen eines vollionisierten Plasmas wird ein Anfangs‐Randwertproblem formuliert und ein Existenz‐ und Einzigkeitssatz bewiesen.
Analysis of fat acid oxidation products by countercurrent distribution methods. V. Low‐temperature decomposition of methyl linoleate hydroperoxide
Authors: Johnston A. E. , Zilch K. T. , Selke E. , Dutton H. J.
Published: June 2007

Methylcis, trans diene conjugated linoleate hydroperoxide isolated by counterenrrent distritbution from 4ŶC, auatoxidation of methyl linoleate was stored in atmospheres of oxygen and of nitrogen at 4ŶC. in darkenss. Besides manometric changes, infrared and ultraviolet characteristics, peroxide value, diene conjugation, and molecular weights were followed on samples removed at various periods of storage up to 53 days. These same analyses were obtained on fractions obtained by counter‐current distributions.

Evidence for the reaction that occurs on storage in oxygen may be summarized thus: 1 mole oxygen absorbed by linoleate hydroperoxides destroys 1 molecis, trans diene conjugation, 1/2 mole peroxide group, and 1 mole linoleate hydroperoxide; dimers of varying polarities, scission acids, and isolatedrans bonds are formed.

Since to volume changes were observed in the nitrogen storage of methyl linoleate hydroperoxide, changes in chemical and physical characteristics can only be related to time of storage. Storage in nitrogen at 4ŶC, destroys diene conjugation, peroxides, and linoleate hydroperoxide and produces dimers of varying polaritics, seission neids, and isolatedrans bonds. Destruction of diene conjugation was one‐fourth as rapid in a nitrogen atmosphere as in oxygen. While differences in reactions and products were observed between oxygen and nitrogen storage, particularly in rates and in countereurrent distribution patterns, the similarity of products from oxygen and nitrogen storage is remarkable. One methyl linoleate hydroperoxide is formed regardless of storage atmosphere, dimirization and attendant destruction of double bonds and peroxides proceed.
In vitro hydrolysis of natural and synthetic γ‐linolenic acid‐containing triacylglycerols by pancreatic lipase
Authors: Huang Yung‐Sheng , Lin Xiaorong , Redden Peter R. , Horrobin David F.
Published: June 2007

The present study compared thein vitro hydrolysis of two 18:3n‐6‐rich oils—evening primrose oil (EPO) and borage oil (BO)—and different synthetic 18:3n‐6‐containing triacylglycerols (TG). Incubation of EPO and BO with pancreatic lipase lipolyzed 18:3n‐6 from the TG species. The rate of lipolysis of TG species containing two or three molecules of 18:3n‐6, which comprised 36% of total 18:3n‐6 in BO and only 7% in EPO, was significantly slower than those containing only one molecule of 18:3n‐6. This was found especially in those with two molecules of linoleic acid, which constituted 20% of total 18:3n‐6 in BO, whereas over 80% were present in EPO. In a separate study, various synthetic 18:3n‐6‐containing TG were also subjected toin vitro hydrolysis by pancreatic lipase. Results showed that release of 18:3n‐6 from thesn‐1/sn‐3 positions was significantly slower when two other stereospecific positions in the same TG molecule were occupied by either palmitic acid (16:0) or monounsaturated (18:1 and 20:1) fatty acids than when occupied by 18:2n‐6. The rate of hydrolysis ofsn‐2‐γ‐linolenyl‐sn‐1(3)‐diacylglycerol to formsn‐2‐mono‐γ‐linolenyl glycerol was also significantly slower when both thesn‐1 andsn‐3 positions in TG molecules were occupied by either saturated fatty acids (16:0 and 18:0) or long‐chain monounsaturated fatty acids than when occupied by 18:2n‐6. These findings suggest that the stereospecific position of 18:3n‐6 in TG molecules and the constituent of its neighboring fatty acids modulated availability of 18:3n‐6 from 18:3n‐6‐containing TG or 18:3n‐6‐rich oils.
Enzymatic synthesis of phosphatidylcholine with fatty acids, isooctane, carbon dioxide, and propane as solvents
Authors: Härröd Magnus , Elfman Inger
Published: June 2007

Phosphatidylcholine (PC) was synthesized from lyso‐PC and long polyunsaturated fatty acids (PUFA) with phospholipase A2. In previous investigations, performed in small glass tubes, the enzymatic synthesis reaction was optimized. This paper presents results from experiments performed in a high‐pressure reactor filled with an immobilized enzyme (Im.E.). Fatty acids were used as the main solvent while isooctane, CO2, or propane was used as an additional solvent. The water content was carefully controlled over wide ranges. The temperature was kept constant at 45°C for up to 50 h. The highest initial reaction rate was attained with pure fatty acids under relatively humid conditions (water=35% of dry Im.E.). The reaction rates were more than three times as high in the high‐pressure reactor than in previous experiments in glass tubes. In all solvent systems, the best yield was attained after long times under dry conditions (water <15% of dry Im.E.). Addition of CO2 to the PUFA reduced the yield, while addition of isooctane or propane increased the yield. After 20 h at 45°C, the best yield (25%) was attained at a solvent composition of 91% PUFA and 9% propane.
Competitive adsorption among sesame oil components in a concentrated miscella system
Authors: Toro‐Vazquez Jorge F. , Mendez‐Montealvo Guadalupe
Published: June 2007

Competitive adsorption of free fatty acids and carotenoids adsorption from sesame oil miscellas on vegetable carbon was studied by regression analysis. The equations obtained indicated that unsaturated carbonyls, free fatty acids (FFA0), and carotenoids interacted to determine fatty acid and carotenoid adsorption. The driving force for carotenoid adsorption, the carotenoid concentration (C0), was affected by a quadratic function of free fatty acid concentration [i.e., (FFA0/C0)2]. As FFA0/C0 increased, carotenoid adsorption efficiency was reduced, possibly because the accessible adsorption sites for carotenoids were occupied by fatty acids. Unsaturated carbonyls promoted free fatty acid adsorption, probably in the pores that were readily accessible for fatty acids. However, when the carbonyl concentration increased in the oil miscella, carbonyls were adsorbed instead of fatty acids. The results indicated how different oil molecules interact and affect adsorption (i.e., free fatty acids and carotenoids). Therefore, the adsorption process of vegetable oils (i.e., bleaching) has to be considered a multicomponent adsorption system.
Thermoacoustic properties of methyl esters ofn‐alkanoic acids
Authors: Cole Sandya , Rao J. V. , Venkatacharyulu P.
Published: June 2007

A number of thermoacoustic parameters, including the Sharma constant S0, the isochoric temperature coefficient of volume expansivity (d Inα/d InT)V, the isochoric temperature coefficient of internal pressure (d InPi/d InT)V, reduced volume V, reduced compressibility β and the Huggins parameter F, are estimated by using only the volume expansivity α from the density temperature data for a number of methyl esters ofn‐alkanoic acids. The methyl esters give excellent separation of saturated fatty acid mixtures. The Sharma constant, which relates the molecular constantn and other thermoacoustic parameters, is a constant with a characteristic value of 1.11+0.01 for all these esters.
Crystal morphology of mixtures of tripalmitin and butterfat
Authors: Fairley Peter , Krochta John M. , German J. Bruce
Published: June 2007

Blends of butterfat and tripalmitin are of interest for use as moisture barriers in edible films. Tripalmitin was blended with butterfat in the ratios 100:0, 90:10, 80:20, and so on through to 10:90 and 0:100. Crystal morphologies of squash and smear preparations were determined by polarizing light microscopy. Samples were stored at 19–22°C and re‐examined after 6 d and after 30 d. Morphology was strongly dependent on composition and the presence of a coverslip. Morphology was less dependent on polymorphic form and age. Barrier properties depend more strongly on morphology than on polymorphic form.
Allylic hydroxy fatty compounds with Δ5‐, Δ7‐, Δ8‐, and Δ10‐Unsaturation
Authors: Knothe G. , Bagby M. O. , Weisleder D. , Peterson R. E.
Published: June 2007

Several novel allylic mono‐ and dihydroxy fatty compounds were synthesized from Δ5, Δ7‐, Δ8‐, and Δ10‐monounsaturated fatty acids with the selenium dioxide/tert‐butyl‐hydroperoxide. Chainlengths were C19 for Δ7 and Δ10, and C20 for Δ5 and Δ8 compounds. With a full range of Δ5‐ to Δ11‐unsaturated allylic monohydroxy fatty compounds available, position‐dependent effects in the13C‐nuclear magnetic resonance spectra of these compounds are discussed. The olefinic carbon shift differences in monohydroxy compounds, where the OH group is located between the double bond and the terminal methyl group, were plotted as a function of double‐bond distance from C1. This plot is presumably a rational function. During SeO2‐based hydroxylation, lactonization of the hydroxy groups, located between the double‐bond and the carboxyl group, also occurs for Δ5 unsaturation.
Chromatographic characterization of internal polar lipids from wool
Authors: Coderch L. , de la Maza A. , Soriano C. , Erra P. , Parra J. L.
Published: June 2007

Wool internal polar lipids were isolated and separated into different fractions based on polarity. Qualitative and quantitative analyses of the different fractions were performed by thin‐layer chromatography and thin‐layer chromatography coupled to flame‐ionization detection, respectively. Cholesterol esters, free fatty acids, sterols, ceramides, glycosylceramides, and cholesterol sulfate were the main components, with ceramides being in the highest proportion. The fatty acid composition of ceramides and glycosylceramides was determined by gas chromatography/mass spectrometry. As for other keratinized tissues, long‐chain fatty acids predominated in comparison to either free fatty acids or phospholipid‐linked fatty acids; in both cases, stearic and lignoceric acids were the most abundant fatty acids, and a low amount of 18‐methyleicosanoic acid was found. This work opens new avenues in the study of lipid rearrangement in more complex and realistic vesicle structures than conventional liposomes.
Structures of ozonolysis products of methyl oleate obtained in a carboxylic acid medium
Authors: Nishikawa Naoki , Yamada Kaoru , Matsutani Shigeaki , Higo Moriaki , Kigawa Hitoshi , Inagaki Takeo
Published: June 2007

High‐performance liquid chromatography‐mass spectrometry (LC‐MS) and nuclear magnetic resonance spectrometry (NMR) were applied to the analysis of organic peroxide mixtures, which were labile and tended to decompose during analysis. The ozonolysis reaction of methyl oleate gives a peroxide mixture, and, finally, mono‐ and dibasic acids are obtained by subsequent oxidation. In this study, methyl oleate was ozonized in a nonanoic acid medium, one of the final reaction products. The reaction products were directly analyzed by LC‐MS equipped with a frit‐fast atom bombardment interface. The molecular ion peak of each peroxide was clearly observed, and its molecular weight was readily determined. On the other hand, each peroxide was fractionated by high‐performance liquid chromatography and submitted to structural analysis by NMR. Both results indicated that the reaction products include four peroxidic species: 1,2,4‐trioxolaneI, peroxide oligomerII, 1‐acyloxyalkyl‐1‐hydroperoxideIII, and 1‐acyloxyalkyl‐1′‐hydroxyalkyl peroxideIV, as well as an aldehydeV. Ozonolysis of methyl oleate in the absence of solvent produces mainlyI, while that in the presence of a carboxylic acid solvent characteristically produces mainlyIII andIV derived from the solvent.Bis(1‐acyloxyalkyl‐1‐alkyl) peroxide, which was reported previously as a ozonolysis product of methyl oleate, was concluded to beIV in this study.
Thermal stability ofThevetia peruviana juss seed oil
Authors: Ibiyemi A. Samuel , Bako S. S. , Ojokuku G. O. , Fadipe V. O.
Published: June 2007

Thevetia peruviana seed showed characteristic changes in physicochemical properties when heated at 180, 200, and 220°C over a period of 15 h. There is no striking significant difference in the five parameters (iodine value, acid value, peroxide value, saponification value, and polar compounds) studied for the three working temperatures. Thevetia seed oil showed good thermal stability and will be a good frying and cooking oil.
Phenylethyl esters of fatty acids for the analytical resolution of petroselinate and oleate
Authors: Liu Linsen , Hammond E. G.
Published: June 2007

2‐Phenylethyl esters of fatty acids were prepared readily by esterification of free fatty acids or transesterification of other lipids. Compared with methyl esters, phenylethyl esters greatly improve the resolution of oleate and petroselinate by both gas and high‐performance liquid chromatography, and the ultraviolet absorption of the phenylethyl esters facilitates detection of the derivatives by high‐performance liquid chromatography (HPLC) ultraviolet detectors. The fatty acid compositions of corn and soybean oil obtained by analysis of phenylethyl esters agreed with those obtained with methyl esters. The phenylethyl esters were resolved and eluted on C‐18 HPLC columns with much smaller solvent volumes than those reported for other aromatic esters.
Co‐metathesis reaction of crude palm oil and ethene
Authors: Ahmad F. B. H. , Hamdan S. , Yarmo M. A. , Alimunir A.
Published: June 2007

The co‐metathesis reaction of crude palm oil with ethene in the presence of WCL6/Me4Sn, followed by termination of this reaction with methanol, gives terminal alkenes. The major metathesis products are 1‐decene and methyl 9‐decenoate.
A wide line NMR R‐F saturation method to measure fat in moist samples of defatted corn germ
Authors: Conway T. F.
Published: June 2007

A wide‐line NMR radio‐frequency (r‐f) saturation technique has been applied to measurement of residual fat (1–6%) in defatted corn germ process samples containing significant amounts (4–11%) of moisture. Since NMR relaxation times for protons associated with the fat differ from those associated with the water, it is possible to use these differences as a basis for discrimination. In process samples where these differences are sometimes marginal, they can often be enhanced by milling the moisture‐containing sample at high speed in carbon tetrachloride to alter the relaxation times of protons associated with the fat. The fat content is derived from NMR signals obtained at two r‐f levels. At the lower r‐f level, energy absorbed is proportional to the number of protons associated with both water and fat. At the higher r‐f level, signals from fat are saturated preferentially. This reduction in signal intensity, due to r‐f saturation, is proportional to the amount of fat in the sample and can be used as a quantitative measurement. Examples of this methodology for laboratory‐prepared and process samples are given. Experimental data for approximately 40 random process samples indicate that the method is accurate to within ±0.3% fat, absolute, 95% confidence limits.
Automated determination of protease for laundry compounds
Authors: Detmar D. A. , Vogels R. J.
Published: June 2007

For the determination of the activity of protease for laundry washing compounds preference is given to casein as substrate and measurement of the supernatant at 275 nm after precipitation with trichloro‐acetic acid. Since sampling rate and precision with the AutoAnalyzer are in this case very low, an automated system based on the principle of the mechanized test tube has been developed. The sampling rate is one sample per minute; the coefficient of variation of a single sample is 2.3% without relation to a standard solution and 1.6% if results are related to a standard solution run simultaneously. If the activity of a sample is determined in threefold, the coefficients of variation are 1.6% resp. 1.1%.
High levels of acetone found in male Turkey skin
Authors: Thomas C. P. , Dimick P. S. , Macneil J. H.
Published: June 2007

Investigation of the carbonyl compounds in the hexane extractable lipid of raw poultry skin revealed that the only monocarbonyl present was acetone. Furthermore, in male turkeys the level of acetone was significantly greater than the level observed in either chickens or female turkeys. During maturation, increased acetone concentrations were accompanied by low lipid deposition in the tissue.
The contribution of saturated acyl groups to the volatiles of oxidized soybean oil
Authors: Michalski S. T. , Hammond E. G.
Published: June 2007

U‐14C‐Stearic acid was interesterified into soybean oil and the resulting oil was oxidized to high peroxide values at 25 C and at 125 C. Volatile oxidation products were isolated and found to have a count that was not significantly above background.
Modification of quantity and quality of safflower oil through plant breeding
Authors: Knowles P. F.
Published: June 2007

Less than 20 years have passed since safflower was established commercially in the southwestern area of the United States. Already hybrid varieties are available, oil and protein contents have been raised greatly, and oil quality has been modified sufficiently to constitute another oil crop for American agriculture. It is hoped that the next 20 years will be equally productive in terms of improvements and modifications of the oil and protein of this crop.
Heats of fusion for some triglycerides by differential scanning calorimetry
Authors: Hampson J. W. , Rothbart H. L.
Published: June 2007

Heats of fusion of tristearin, tripalmitin, trimyristin, trilaurin and several standards were determined by the relatively new technique of Differential Scanning Calorimetry. The data obtained on the standards shows good precision and accuracy. The results obtained for the triglycerides are 1–10% lower than values which have been reported elsewhere.
Some recent developments in the isolation and synthesis of lipids
Authors: Lundberg W. O.
Published: June 2007

The isolation of certain lipids in pure form from complex natural mixtures, and improved procedures for the synthesis of fatty acids and their esters, of synthetic intermediates, of alkoxylipids, and of some other unusual lipids are reviewed.
Hydrogenation of unsaturated fatty acids to unsaturated fatty alcohols: III. Comparison of different soap catalyst systems
Authors: Richter J. D. , van den Berg P. J.
Published: June 2007

Copper oleate and cadmium oleate catalysts have been replaced by other metal compounds. Silver was the only metal which could be substituted for copper in the ratio range studied. Using nickel oleate, the degree of saturation of the double bond decreased with increasing cadmium oleate concentration. No comparable substitute was found for Cd. The composition of the final components is influenced by the use of a paraffinic solvent, which also has an effect on the saturation of the double bond. An explanation is given for the behavior of the catalyst when the reaction is not selective and is carried out in a paraffinic solvent. The catalytic system Ag/Cd soaps was also studied kinetically and analytically. The results show that the mechanism of the reaction using silver soap is identical with the one using copper soap.
Photolytic synthesis of methyl sterculate containing mixture from methyl stearolate and diazomethane
Authors: Schlosser Martin M. , Longo Angelo J. , Berry James W. , Deutschman Archie J.
Published: June 2007

A method for synthesis of a mixture containing methyl sterculate is described. The presence of the cyclopropene compound was verified by Halphen Test, infrared absorption and the effect on fatty acid distribution in egg yolks produced by hens consuming the synthetic product.
Surfactant analysis by matrix‐assisted laser desorption time‐of‐flight mass spectrometry
Authors: Thomson Barry , Wang Zhiyu , Paine Anthony , Rudin Alfred , Lajoie Gilles
Published: June 2007

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry was used to characterize nonionic, anionic and cationic surfactants. Rapid mass analyses can be achieved with proper choice of matrix material. The technique is suitable for development as a routine analytical tool.
Measurement and interpretation of zeolite NaA builder performance
Authors: Denkewicz Raymond P. , Monino Anita G. , Russ Deborah E. , Sherry Howard S.
Published: June 2007

Ion exchange isotherms are commonly used to describe the distribution of ions between a solid and liquid phase under equilibrium conditions. In the detergent industry, the Ca‐Na‐zeolite A isotherm can be utilized to determine the builder performance of zeolite NaA under a specific set of experimental conditions. In this paper, we demonstrate how the Ca‐Na‐zeolite A isotherm is developed and utilized in measuring and interpreting the calcium exchange capacity score of zeolite NaA. Owing to the large number of testing parameters that affect the equilibrium distribution of calcium between the zeolite and solution phases, and hence the calcium exchange capacity score of the zeolite, a recommendation is made as to a standard set of test conditions that provide for both analytical precision and convenience. With this approach, builder performance differences between any two zeolites can then easily be measured and assessed. As an extension to the isotherm principles developed in this paper, the prediction of zeolite performance in real detergent systems is illustrated. Particular attention is given to the more efficient utilization of the ion exchange capacity of zeolite NaA by the recently developed concentrated detergent systems.
Surface tension studies on novel allylic mono‐and dihydroxy fatty compounds. A method to distinguisherythro/threo diastereomers
Authors: Knothe G. , Dunn R. O. , Bagby M. O.
Published: June 2007

The suitability of the selenium dioxide/tert.‐butyl‐hydroperoxide system for obtaining allylic mono‐ and dihydroxy fatty compounds has recently been reported. The surface tension of some selected products was determined in 1N NaOH and compared to that of some known materials, such as ricinoleic acid. The surface properties of the novel monohydroxy fatty acids are comparable or better than those of the reference materials. The critical micelle concentrations of the novel monohydroxy acids are in the range 10−4–10−3 mol/L, depending on their structure. Furthermore, the monohydroxy acids were more effective when the hydroxy group was closer to the functional group at C1. Allylic dihydroxy acids also lowered the surface tension but less so than the monohydroxy compounds. Theerythro andthreo diastereomers of the allylic dihydroxy acids can be distinguished by surface tension, with thethreo diastereomers possessing better surfactant properties. Mixtures of the novel hydroxy fatty acids are also effective, thus obviating the need for complete purification of the products. Side products such as enones, which are formed during the allylic hydroxylations, also lower the surface tension. The products may be suitable for use in microemulsions or as additives in various commercial products.
Fluorescence technique for the determination of low critical micelle concentrations
Authors: Mehreteab Ammanuel , Chen Betty
Published: June 2007

A technique for determining low critical micelle concentrations (CMC) by means of a hydrophobic fluorescence probe has been developed. The amount of the fluorescent probe at the CMC is so small that the effect of the probe on micelle formation is negligible. The fluorescence intensity was measured at fixed dye/surfactant ratios, and it decreased with concentration. A quantity proportional to fluorescent quantum yield was calculated and found to be high for concentrations of surfactant above the CMC and almost zero below the CMC, giving a distinct break in the quantum yield vs. the concentration curve.
Preparations and reactions of alkyl ethers of some aldohexoses
Authors: Urata Kouichi , Yano Shinji , Takaishi Naotake
Published: June 2007

Aldohexose, such asd‐glucose,d‐galactose ord‐mannose, reacted with acetone to give the following O‐isopropylidene derivatives: 1,2;5,6‐di‐O‐isopropylidene‐d‐glucofuranose (IA), 1,2;3,4‐di‐O‐isopropylidene‐d‐galactopyranose (IB) or 2,3;5,6‐di‐O‐isopropylidene‐D‐mannofuranose (IC). The O‐isopropylidene derivative (IA∼IC) reacted with alkyl/alkenyl halogenide to yield aldohexose ether compounds containing di‐O‐isopropylidene group, 3‐O‐alkyl‐1,2;5,6‐di‐O‐isopropylidene‐d‐glucofuranose (II), 6‐O‐alkyl‐1,2;3,4‐di‐O‐isopropylidene‐d‐galactopyranose (III) or 1‐O‐alkyl‐2,3;5,6‐di‐O‐isopropylidene‐d‐mannofuranoside (IV), in good yields. The Williamson ether synthesis was carried out using phase‐transfer catalysis (PTC). The derived aldohexose alkyl ether containing di‐O‐isopropylidene group was hydrolyzed to give 3‐O‐alkyl‐1,2‐O‐isopropylidene‐d‐glucofuranose (V) as a partial hydrolysis product; the complete hydrolysis of I∼IV gave, as expected, 3‐O‐alkyl‐glucopyranose (VI), 6‐O‐alkyl‐galactopyranose (VII) or 1‐O‐alkyl‐mannofuranoside (VIII). Further alkylation of (V) with Mel under PTC and subsequent acid hydrolysis gave 3‐O‐alkyl‐5,6‐di‐O‐methyl‐d‐glucofuranose (X). Methanolysis of III with catalytic amounts of H2SO4 gave 1‐O‐methyl‐6‐O‐alkyl‐d‐galactofuranoside (XI). The elucidation of the galactofuranoside skeleton of (XI) was determined by means of its13C nuclear magnetic resonance spectra. The O‐alkyl aldohexoses, e.g., X and XI, were evaluated and found to be emulsifiers.
Synthesis and characterization of cleavable cationic surfactants with a 1,3‐dioxane ring
Authors: Wang Guan‐Wu , Yuan Xian‐You , Liu You‐Cheng , Lei Xue‐Gong , Guo Qing‐Xiang
Published: June 2007

A series of cationic cleavable surfactants was prepared by condensation of 2‐alkyl‐1,3‐propanediols with 3‐bromopropanal, followed by reaction with triethylamine. Each surfactant is a mixture of two diastereomers, and their precursors’ stereochemical assignments were based on1H nuclear magnetic resonance spectra and melting points. The critical micelle concentrations, Krafft points and destructibility of these surfactants were determined.
Reaction of sodium perborate with a chlorinated cyclic hindered amine (N‐chloro‐4‐hydroxy‐2,2,6,6‐tetramethylpiperidine) II. Activating effects and related characteristics in practical fabric bleaching
Authors: Fujiwara Masami , Tamura Takamitsu , Nishida Shigeo , Akabane Yasuhiro
Published: June 2007

A synergetic bleaching activation phenomenon of the chlorinated cyclic hindered amine, N‐chloro‐4‐hydroxy‐2,2,6,6‐tetramethylpiperidine (TMP‐Cl) on sodium perborate (PB) was examined under some practically applicable bleaching procedures. By combining TMP‐Cl with PB, the bleaching effect toward black tea, fruit juices and other stains was enhanced synergetically, achieving an efficiency similar to that of the well‐known tetraacetylethylenediamine/PB system. However, behavior observed in the TMP‐Cl/PB system, such as high bleaching efficiency in an alkaline range, superior durability for repeated bleaching, less discoloration of cloth that contains reactive dyes and no influence on the activity of an enzyme, was favorable for a bleaching component of heavy‐duty detergents.
A novel sample preparation for chloride analysis in bar soaps
Authors: Molever K.
Published: June 2007

A simple and rapid sample preparation technique is described for the potentiometric determination of chloride in bar soaps. Usual preparation of soap for potentiometric chloride analysis involves time‐consuming dissolution of the sample in water or heating to affect dissolution, followed by a cooling step. Also, when performing potentiometric titrations for chloride under the usual acid conditions, aqueous solutions of soap bars (unlike combination soap/detergent bars) will form insoluble semisolid fatty acids that can occlude some chloride and make clean‐up difficult. This paper describes a simple dissolution of bar soap sample in dilute H2SO4/methanol at ambient temperature that simultaneously acidifies the sample solution and produces noninterfering methyl esters from the soap fatty acids; water is then added, and the chloride is determined potentiometrically with standardized AgNO3. This procedure has been shown to work well with automatic titrators.
Comparison of high‐temperature gas chromatography and CO2 supercritical fluid chromatography for the analysis of alcohol ethoxylates
Authors: Silver Alan H. , Kalinoski Henry T.
Published: June 2007

This work compares capillary supercritical fluid chromatography (SFC) and capillary high‐temperature gas chromatography (HTGC) for the quantitative characterization of nonionic alcohol ethoxylate surfactants. Supercritical fluid chromatographic separations of the alcohol ethoxylates were obtained with a density‐programmed carbon dioxide mobile phase and a fused silica capillary column. High‐temperature gas chromatographic separations were obtained with a high‐temperature polyimide‐coated fused silica capillary column. In addition, a procedure was developed for the quantitation of the capillary chromatographic data using flame ionization molar response factors based on the effective carbon theory. The alcohol and ethoxylate distributions, mean molecular weights and average moles of the ethylene oxide are rapidly calculated from the chromatographic data. Advantages and limitations of SFC and HTGC procedures are illustrated and discussed. Based on this work, the following conclusions can be drawn: i) For routine quality control analyses of known alcohol ethoxylates, SFC and HTGC appear to be equally applicable. ii) SFC has the advantage of time because derivatization is not required, although derivatization does improve resolution. iii) HTGC has the advantage of resolving C12 through C18 alcohol ethoxylate oligomers, avoiding ambiguous identification of components. iv)SFC and HTGC both have disadvantages. SFC has a resolution limitation and HTGC discriminates against high molecular‐weight components.
A system for determining optical brighteners in laundry detergents by TLC and HPLC
Authors: Jasperse J. L. , Steiger P. H.
Published: June 2007

Twenty‐three optical brighteners have been separated on a thin‐layer chromatographic (TLC) system and a high‐performance liquid chromatographic (HPLC) system. These systems can be used to identify and quantitate optical brighteners in laundry detergents. The TLC system uses four solvent‐absorbent combinations. The HPLC system uses a C8 column and a binary solvent gradient program to separate the optical brighteners.
Synthesis of diethanolamides of N‐lauroyl dipeptides and correlation of their structures with surfactant and antibacterial properties
Authors: Mhaskar S. Y. , Lakshminarayana G.
Published: June 2007

Diethanolamides (DEA) of proteins possess nonionic skin‐compatible, biodegradable, surfactant and antibacterial properties. The DEA of dipeptides are, however, too hydrophilic to be effective surfactants. Hence, DEA of N‐lauroyl dipeptides were synthesized and their surfactant and antibacterial properties were correlated with the structures of amino acid moieties. N‐Lauroyl condensates of five simple amino acids were coupled with the corresponding amino acid methyl esters and the resulting products were condensed with diethanolamine in the presence of sodium methoxide to yield DEA of N‐lauroyl dipeptides. The DEA of N‐lauroyl glycine dipeptide showed surfactant properties comparable to lauroyl diethanolamide. The thiol group in the cysteine derivative exerted an unfavorable effect on surfactant properties. The isobutyl side chain in the leucine derivative contributed greatly to the antibacterial activity when compared to the other amino acid derivatives studied.
Lipopeptidic surfactants. II. Acidic and basic Nα‐lauroyl‐L‐arginine dipeptides from pure amino acids
Authors: Infante M. R. , Mollnero J. , Erra P.
Published: June 2007

In this paper, the second part of a systematic study whose aim deals with the influence of the terminal amino acid side chain on the properties of Nα‐lauroyl arginyl dipeptides is reported. Nα‐lauroyl arginyl dipeptides that contain an acidic amino acid (glutamic acid) or a basic amino acid (lysine) as terminal amino acid have been prepared by peptide synthesis methods. These compounds have been synthesized as methyl esters (cationic surfactants) and free α‐carboxylic acids (amphoteric surfactants), and their fundamental surfactant properties and antimicrobial activity have been evaluated. The properties of these compounds have been compared to the properties of the cationic monomer derivative methyl ester of Nα‐lauroyl arginine and of the amphoteric monomer derivative Nα‐lauroyl arginine reported earlier.

The compounds are soluble in water and show surface activity, although in the case of the amphoteric Nα‐lauroyl arginyl dipeptide containing glutamic acid these two properties depend on the solution pH. The cationic Nα‐lauroyl arginyl dipeptides are antimicrobial agents. However, only the amphoteric compound containing lysine may be considered antimicrobial.
Phase diagrams of water and sodium dodecyl sulfate combined with four commercial nonionic surfactants
Authors: Friberg S. E. , Chiu M.
Published: June 2007

Phase diagrams in which water was combined with sodium dodecyl sulfate, plus one of four nonionic surfactants, as well as an aliphatic oil, were determined by visual observation and low‐angle X‐ray diffractometry. The results agreed with earlier investigations on specially synthesized polyethyleneglycol alkyl ether surfactants, except that the extended water‐in‐oil microemulsion areas were not found with the commercial surfactants.
Flow behavior of sucrose stearate/water systems
Authors: Calahorro C. , Muñoz J. , Berjano M. , Guerrero A. , Gallegos C.
Published: June 2007

The aim of this work was to carry out a rheological study of aqueous systems containing a nonionic surfactant derived from sugar. The compositions studied ranged from the micellar region up to the occurrence of fully developed liquid crystals. This study was carried out at 50°C.

Systems up to 2% (wt) sucrose stearate exhibited a power‐law decrease in the steady‐state apparent viscosity with shear rate. At higher sucrose stearate concentrations, the flow curves exhibited two well‐defined regions depending on shear rate, so that the apparent viscosities fitted the Carreau model A [Carreau, P.J., D. De Kee and M. Daroux,Can. J. Chem. Eng. 57:135 (1979)]. The existence of three composition ranges is proposed. An increasingly stronger micellar structure, as surfactant concentration rises, extends up to 10% (wt) sucrose stearate. Between 15% and 35% (wt) sucrose stearate, the results obtained are consistent with the occurrence of a lamellar liquid‐crystal dispersion in an isotropic micellar solution. The liquid crystalline content in the dispersion steadily increases with surfactant concentration up to reaching a fully developed lamellar liquid crystal at 40% (wt) sucrose stearate.
Performance and physicochemical properties of α‐sulfo fatty acid methyl esters
Authors: Satsuki Teruhisa , Umehara Kenji , Yoneyama Yuji
Published: June 2007

The detergency properties of α‐sulfonated fatty acid methyl esters (α‐SFMe) were evaluated and compared to those of conventional anionic surfactants by using a model heavy‐duty detergent formulation. Several physicochemical properties of surfactants were measured to investigate the effective factors on detergency. α‐SFMe showed good detergency performance under various washing conditions. These results were considered to correlate well with the good adsorption behavior on oils and dispersing capabilities for particles, as well as with the good solubilization capacity. Solubilization behavior of α‐SFMe is discussed in relation to micelle properties. It is suggested that α‐SFMe can form suitable micelles for solubilizing polar oils advantageously, due to its bulky hydrophilic group.
Detergency of binary mixtures of LAS/STPP and LAS/Zeolites: influence of (Ca++) on the washing liquor
Authors: Cohen L. , Moreno A. , Berna J. L.
Published: June 2007

The influence of sodium tripolyphosphate (STPP) or zeolites on the detergency performance of linear alkylbenzene sulfonate (LAS) has been evaluated at different water hardness levels. This study demonstrates that STPP or zeolite behaves either as a sequestrant or through an important synergism with LAS, showing a minimum and a maximum in detergency performance, depending on the water hardness level. There is an optimum LAS/builder ratio for each individual water hardness level. This optimum has to be determined experimentally as it will not always necessarily coincide with the highest surfactant and/or builder concentrations.
Alkylphenol ethoxylates in the environment
Authors: Naylor Carter G. , Mieure James P. , Adams William J. , Weeks John A. , Castaldi Frank J. , Ogle Larry D. , Romano Robert R.
Published: June 2007

A comprehensive monitoring study, sponsored by the Chemical Manufacturers Association and designed in cooperation with the Environmental Protection Agency (EPA), measured the levels of nonylphenol (NP) and its ethoxylates (NPE) in 30 rivers. The sites, all receiving municipal or industrial wastewater, were selected at random from EPA’s United States river reach database by a statistical procedure. Water column and bottom sediment samples were collected along a perpendicular transect at each site. All samples were assayed for NP and NPE1, and the higher ethoxylates (NPE2 to NPE17) were determined in the water samples. Analysis was by high‐performance liquid chromatography (HPLC) with fluorescence detection of microgram quantities of NPE obtained by extractive steam distillation (NP and NPE1) or a dualcolumn extraction procedure (NPE2 to NPE17). Sample collection and analytical procedures were validated according to rigorous EPA guidelines, and quality assurance standards were met throughout the study. NP and NPE concentrations in river water were mostly (60 to 75% of the samples) below their detection limits (about 0.1 ppb for NP, NPE1, and NPE2; 1.6 ppb for NPE3–17). The highest levels found were about 1 ppb for NP, NPE1, and NPE2, 15 ppb for NPE3–17. A majority of sediment samples contained detectable amounts of NP and NPE1, ranging up to 3000 ppb for NP and 170 ppb for NPE1. Sediment interstitial water concentrations of NP were estimated to be similar to concentrations in the water column.
The separation of solid fatty acids from liquid fatty acids by the formation of acid soaps. I. Tallow soaps
Authors: Munns W. O. , Kairys S. , Manion Dilys A. , Meade E. M.
Published: June 2007

The formation of acid soaps has been used successfully for the separation of a mixture of fatty acids into high and low iodine value fractions. The acid soaps of saturated acid can be made to crystallize from water leaving their unsaturated counter parts in solution. Acid soaps of saturated fatty acids are well characterized compounds with the formula R‐COOM.R‐COOH, where R is a straight alkyl chain, and M is sodium, potassium or ammonium.

Optimum crystallization conditions involve a soap concentration of 2舑5%, pH adjustment to between 7.0 and 8.0, an initial crystallization temperature not below 25C, and a crystallization period of at least 4 hr during which time cooling to a final temperature of 5舑10C must be gradual, and agitation gentle.
The separation of solid fatty acids from liquid fatty acids by the formation of acid soaps. II. Pilot plant studies
Authors: Munns W. O. , Kairys S. , Manion Dilys A. , Meade E. M.
Published: June 2007

On contemplating pilot plant scale‐up of the acid soap process for separating fatty acid mixtures into low and high iodine value fractions, improvements were desirable in acidifying agent used, and the method of separating the solid acid soaps. A further objective was to determine the range of applicability of the process.

Studies indicated that CO2 can be replaced by mineral acids, or by the fatty acids themselves. A continuous precoat vacuum filter is suitable for the separation of the solid acid soaps. The process is applicable to refinery foots as well as to distilled and undistilled fatty acids.
New methods of analyzing industrial aliphatic lipids
Authors: Mangold Helmut K. , Kammereck Rudolf
Published: June 2007

Methods are described for the rapid fractionation of classes of lipids containing the hetero elements N, P, and S such as primary amines, secondary amines, tertiary amines, and quaternary ammonium salts containing one, two, or three long‐chain moieties; amides, nitriles, and other nitrogenous lipids; alkyl sulfates and sulfonates; alkyl phosphates and phosphonates.

Thin‐layer chromatography on silicic acid separates lipids according to classes of compounds. After isolation by thin‐layer chromatography, each lipid class is amenable to further fractionation, according to chain length and degree of unsaturation, by complementary methods, such as paper chromatography and/or gas‐liquid chromatography.

These procedures permit rapid analyses of complex mixtures of industrial lipids, such as surface‐active agents, and identification of industrial compounds synthesized from fatty raw materials.