Analyses of free fatty acids (saturated, branched and unsaturated) by reverse phase high-performance liquid chromatography have been studied at low wavelengths (196220nm) by using a variabe wavelength UV detector, and aqueous methanol containing 0.1% phosphoric acid as eluent. Plots of logarithm of the corrected retention volume against the carbon number of saturated straight chain fatty acid gave good linear relationship, from which C values of branched and unsaturated fatty acids were estimated. C values of branched and some unsaturated fatty acids were constant independent of water content of eluent, however, those of polyunsaturated fatty acids increased with increasing the water content. C values of branched and unsaturated fatty acids were smaller than their total carbon numbers, respectively. This shows that these acids are more polar than the corresponding straight chain fatty acids, respectively. Resolution of geometrical and positional isomers of unsaturated fatty acids was performed. Movement of double bonds toward the polar end and cis form increased the polarity of the acids to a slightly greater than the corresponding isomeric forms, respectively. These observations were discussed by the interaction between the acids and the reverse phase. Relative response of unsaturated fatty acids against dodecanoic acid (12 : 0) has been estimated. The plots of S (unsaturated fatty acid) /S (12 : 0) against Wt (unsaturated fatty acid) /Wt (12 : 0) gave linear relationship, demonstrating a possibility of stable and easily available saturated fatty acids as internal standards for the quantitative HPLC analyses of unsaturated fatty acids and the related compounds that have the absorption only at low wavelengths. The relative response of unsaturated fatty acids against 12 : 0 increased with decreasing the detection wavelength. Unsaturated fatty acid compositions of some vegetable oils were determined using the relative response, in agreement with the results in the GLC analyses.

View full abstract

The values of cmc of alkyltrimethylammonium bromides having hydrocarbon chain with 1014 carbon atoms were determined in distilled water at 15, 20, 25, 30, 35, and 40°C. Thermodynamic parameters for micellizations of these surfactants (ΔGm : free energy of micellization, ΔHm : enthalpy of micellization, and ΔSm : entropy of micellization) were then calculated. There was a linear relationship between ΔHm and ΔSm for each of these surfactants; the straight lines were parallel with each other. The main cause for this is that the extent of breakdown of the clustered water, which surrounds the hydrocarbon chain of the surfactant, in the micellization process differs depending on the length of hydrocarbon chain.

View full abstract

High resolution gas chromatography of fatty acid methyl esters prepared from ten samples of refined vegetable oils was carried out on glass capillary columns. Effective separations of the positional isomers of monounsaturated fatty acids, the trans-9, cis-12 isomer of linoleate, and the cis-9, cis-12, trans-15 and trans-9, cis-12, cis-15 isomers of linolenate were performed on a Silar-5 CP or SP 2300 column. Additionally, the cis-9, trans-12, isomer of linoleate was separated on a Silar-10c or SP 2340 column. The cis-9, trans-12, cis-15 isomer of linolenate has not been detected in this study. Conversion of linolenate to the trans isomers during the refining process was 1329%, and that of linoleate was about 10% of the conversion of linolenate to the trans isomer. The fatty acid composition of refined vegetable oils is presented in detail.

View full abstract

Crude tall oils imported from five countries were analyzed by glass capillary gas chromatography. The 5-olefinic fatty acids they contained consisted of cis-5, cis-9-octadecadienoic acid (5, 9-18 : 2), 5, 9, 12-18 : 3, 5, 11-20 : 2, and 5, 11, 14-20 : 3; the proportions varied widely among the samples. For the effective separation of a specified 5-olefinic acid, it is important to select suitable crude tall oils as original material. The contents of the 5-olefinic acids in the total fatty acids increased with increasing contents of linoleic acid and with decreasing oleic acid in the samples analyzed.

View full abstract

Reversed phase high performance liquid chromatography (HPLC) on methyl silica column was used for the separation of phospholipids including phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), phosphatidyl inositol (PI) and phosphatidyl serine (PS) in naturally occurring samples.
Hexane/2-propanol/water (1 : 60 : 39) was one of the best eluents for the separation of these phospholipids which were detected at 210nm.
The molar extinction coefficient of each phospholipid is not yet known and it is very difficult to obtain an authentic sample, so that purified soybean phospholipids, quantitated by Reinecke's salt method for PC and by 2, 4-dinitro-1-fluorobenzene (DNFB) method for PE, were used as standard samples for the determination of PC and PE.
The calibration curves between the amount and the peak height in the HPLC were obtained with good linearity ranging from 3.7 to 74μg for PC and from 0.7 to 6.6μg for PE.
PC and PE in some phospholipids such as soybean, egg yolk, pig liver and dry yeast (Saccharomyces cerevisiae sp.) phospholipids were determined with reliable accuracy under the conditions employed.
The present method can be used for the routine quantitation of PC and PE in various phospholipids prepared from plant and animal sources.

View full abstract

To compare the effects of various metals (periodic group VI) on the autoxidation of methyl oleate and the decomposition of methyl oleate hydroperoxide in methyl oleate, the substrates were kept with metal carbonyls [Mo (CO) ₆, Cr (CO) ₆ and W (CO) ₆] at 80°C.
The effects of the catalysts were investigated by observing the changes in peroxide value, iodine value, saponification value, refractive index, molecular weight, and trans isomer content. The identification of autoxidation products of methyl oleate and decomposition products of methyl oleate hydroperoxide were carried out by gas chromatography of trimethylsilyl ether derivatives.
Mo (CO) ₆ showed marked effect on the autoxidation of methyl oleate and the decomposition of methyl oleate hydroperoxide. The products were found as methyl cis-epoxyoctadecanoate and methyl hydroxyoctadecenoate, which were produced by intermolecular reaction among methyl oleate and methyl oleate hydroperoxide. Moreover, methyl hydroxyepoxyoctadecanoate was also produced by intramolecular reaction of methyl oleate hydroperoxide itself.
Cr (CO) ₆ showed more marked effect than Mo (CO) ₆. The autoxidized products of methyl oleate were identified as methyl trans-epoxyoctadecanoate, methyl cis-epoxyoctadecanoate, methyl hydroxyoctadecenoate and methyl oxooctadecenoate, but methyl hydroxyepoxyoctadecanoate was not produced. Methyl oxooctadecenoate and methyl hydroxyoctadecenoate were produced by decomposition of methyl oleate hydroperoxide in the presence of Cr (CO) ₆, but W (CO) ₆ showed almost no effects.

View full abstract

The stabilities of 20% fluorocarbon (FC) /water emulsions containing 5% fluorinated nonionic surfactants were determined by measuring the variation of droplet diameter distribution with time (up to 10 months). For comparison of less effective emulsifiers, the rate of phase separation was also used.
O/W emulsions containing HCF₂ (CF₂) ₃CH₂O (C₂H₄O) _9.7H showed low stability, but those stabilized by HCF₂ (CF₂) ₇CH₂O (C₂H₄O) _10.5H showed excellent stability. Although emulsions containing HCF₂ (CF₂) ₅CH₂O (C₂H₂O) _10.3H separate a minor proportion of the aqueous phase in a relatively short time, the distribution of FC droplet diameter changed little over a long period.
In the present investigation, emulsions stabilized by CF₃ (CF₂) ₆CH₂O (C₂H₄O) _10.3H exhibited the highest stability, indicating the importance of a greater affinity of the terminal CF₃ group for FC.
The percentages of the aqueous phase formed 5h after preparation of emulsions containing various surfactants were as follows : HCF₂ (CF₂) ₇CH₂O (C₂H₄O) _10.5H (0%), CF₃ (CF₂) ₆CH₂O (C₂H₄O) _10.3H (00.3%), CF₃ (CF₂) ₅CH₂O (C₂H₄O) _10.3H (00.6%), HCF₂ (CF₂) ₃CH₂O (C₂H₄O) _9.7H (01%), HCF₂ (CF₂) ₅CH₂O (C₂H₄O) _10.3H (12.613.4%), CH₃ (CH₂) ₁₁O (C₂H₄O) ₈H (6670%).

View full abstract

6, 10-Dimethyl-2-undecanone (10), a key intermediate for squalane and isophytol, was effectively synthesized from prenyl chloride (4a, b) via telomerization with isobutylene and hydroformylation with cobalt catalyst followed by aldol condensation with acetone.
Telomerization of (4a, b) with excess amount of isobutylene was carried out in the presence of zinc chloride catalyst to obtain 6-chloro-2, 6-dimethyl-2-heptene (5) in 63.5%. Dehydrochlorination of (5) was investigated under various conditions. A mixture of 2, 6-dimethyl-1-heptene (7a) and 2, 6-dimethyl-2-heptene (7b) was obtained from (5) by hydrogenation followed by dehydrochlorination. Hydroformylation of the mixed products (7a, b) with cobalt catalyst proceeded with migration of the double bond to yield 3, 7-dimethyloctanal (8) as the sole product which was converted to (10) by aldol condensation with acetone and by selective hydrogenation.

View full abstract

Fluorination of various terpenic alcohols and fatty alcohols with N, N-diethyl-1, 1, 2, 3, 3, 3-hexafluoropropyl amine (PPDA) was carried out. A mixture of 2- (2'-fluoroethyl) -6, 6-dimethyl-bicyclo [3.1.1] hept-2-ene (2) and nopyl 2, 3, 3, 3-tetrafluoropropionate (3) was obtained from the reaction of nopol (1) with PPDA. Similar results were obtained from other terpenic alcohols and fatty alcohols.

View full abstract