Thermal behavior of polyformates of milkweed and soybean oils

Reprocessing neat vicinal polyformate esters of milkweed and soybean triglycerides in a silica-drying column with mild heating resulted in a light reddish-orange gel formation of the column eluate on cooling. Analysis of gel by ¹H- and ¹³C-NMR showed characteristics of possible elimination, which include olefinic/aromatic moieties and formic acid. Rearrangement of triglyceride skeleton leads to crosslinking. FTIR spectrum of the gel suggested formation of olefinic species. Trial runs to reproduce the column results by heating aliquots of the neat vicinal polyformate under N₂ with and without silica gel generated a gas that discharged basic phenolphthalein solution. Further heating gave a tacky off-white polymer that was chloroform insoluble. In contrast, the vicinal polyacetate derivatives of milkweed and soybean oils were stable under similar reaction conditions. From the rheological similarity of their power-law exponents, 0.63 and 0.70, respectively, MWF gel and SoyF gel can have similar behavior during processing. Published 2019. This article is a U.S. Government work and is in the public domain in the USA. J. Appl. Polym. Sci. 2019 , 136, 48225.     

One-pot solvent-free transformation of natural triglycerides to ester and amide derivatives over CaO@KC nanostructured catalysts

In the present report, the fatty acid alkyl esters and fatty acid amides were synthesized from natural triglycerides by highly selective solvent-free one-step methods using 3.5-CaO@KC-400 nanocrystals as a heterogeneous catalyst. A modified wetness chemical impregnation method was used to prepared potassium carbonate-doped CaO, ZnO, and MgO nanocrystals. The prepared 3.5-CaO@KC-400 nanocrystals were found as the most efficient heterogeneous catalyst (5%, w/w) for amidation (6:1 M ratio of diethanolamine/oil, 110°C) and transesterification (12:1 M ratio of methanol/oil, 65°C) of waste cooking oil and took 30 minutes for the completion of both the reactions. The 3.5-CaO@KC-400 nanocrystals were found to be efficient at room temperature also and reused for 10 reaction cycles for both reactions. The pseudo-first-order kinetic model was applied and the first-order rate constant was calculated as 0.15 minute⁻¹ and 0.103 minute⁻¹ for the amidation and transesterification reactions of waste cooking oil, respectively.     

Sterolic composition and triacylglycerols of Oueslati virgin olive oil: comparison among different geographic areas

The main triglycerides (TG) identified in the Oueslati virgin olive oil were 1,2,3‐trioleylglycerol (OOO), 2,3‐dioleyl‐1‐palmitoylglycerol (POO) and 2,3‐dioleyl‐1‐linoleylglycerol (LOO) representing more than 80% of the total area of peaks in the chromatogram. Other minor triacylglycerols were 2,3‐dioleyl‐1‐stearoylglycerol (SOO), 2‐oleyl‐3‐palmitoyl‐1‐stearoylglycerol (SOP), 1‐linolenoyl‐2‐oleyl‐3‐palmitoylglycerol (LnOP), 1, 2‐dilinoleyl‐3‐palmitoylglycerol (LLP), 1, 3‐dioleyl‐2‐linolenoylglycerol (OLnO), 1‐linolenoyl‐2‐linoleyl‐3‐oleylglycerol (LnLO) and 1,2,3‐trilinoleylglycerol (LLL). The sterol profile of Tunisian virgin olive oils produced from Oueslati cultivar was established by gas chromatography using a flame ionisation detector (GC‐MS). More than 10 compounds were identified and characterised. As expected for virgin olive oil, the main sterols found in all Oueslati olive oils were β‐sitosterol, Δ5‐avenasterol, campesterol and stigmasterol. Cholesterol, 24‐methylenecholesterol, clerosterol, campestanol, sitostanol, Δ7‐stigmastenol, Δ5, 24‐stigmastadienol and Δ7‐avenasterol were also found in all samples, but in lower amounts. Most of these compounds are significantly affected by the geographical origin of the oil. Besides the sterol components, two triterpene dialcohols, erythrodiol and uvaol, were also detected.     

芝麻油掺菜籽油鉴别方法的研究

以5种不同芥酸含量的菜籽油与4种芝麻油所配制的120个掺伪油样为原料,分别采用全样脂肪酸组成分析法、Sn-2位脂肪酸组成分析法和甘三酯组成分析法对芝麻油中掺菜籽油的鉴别方法进行了研究.结果表明:在全样脂肪酸和Sn-2位脂肪酸组成分析法中,当分别以花生一烯酸和亚麻酸含量为标准判断检出限时,检出限最低,分别为5％和4％;甘三酯组成分析法中,以β-LOL和β-PLL含量之和为判断标准检出限为21％.综合这3种方法认为:全样脂肪酸组成分析法是芝麻油掺菜籽油的最好鉴别方法,其余2种方法只是对上述方法的一种验证与补充,一般不优先采用.     

Comparison Between Turnover Rates of CO Oxidation over Rh0 or Rhx+ Supported on Model Three-Way Catalysts

The kinetics of CO oxidation over two catalytic sites, either 100% zero-valent or 100% oxidised rhodium atoms, were studied. It was shown that an oxidised rhodium species exhibits a significant higher turnover rate in CO oxidation (factor 25) than the corresponding zero-valent one. This noticeable difference, interpreted with respect to mechanistic considerations, led us to conclude that one of the promoting effects of ceria–zirconia is to stabilise rhodium atoms as oxidised species.     

Rejection of carotenoids in oil systems by a nonporous polymeric composite membrane

Ealier studies by the authors on crude vegetable oils showed that color compounds are reduced to the extent of 74–80% during membrane processing. In the present study, attempts were made to understand the rejection mechanism of carotenoids using real and model oil systems. In case of model systems consisting of refined high-oleic sunflower (HOSF) oil, lecithin and β-carotene, the rejection of carotenes was low (11–20%). This could be explained based on the differences between the model and real systems as well as on the solution-diffusion mechanism controlling the material transport across the membrane. This study revealed that β-carotene did not have affinity for the phospholipid reverse micells present in the oil. Xanthophylls, the major carotenoids present in the crude soybean oil, were rejected to the extent of 60% in the model system (HOSF oil and lutein). High-performance liquid chromatographic analysis of crude oil revealed that there were few other xanthophylls, which are more polar than lutein. These unidentified xanthophylls would be rejected to a much greater extent by the hydrophobic membrane. The extent of color reduction would depend on the actual composition of xanthophylls present in the crude oil and their relative polarity.     

Aberrations in Lipid Expression and Metabolism in Psoriasis

Psoriasis (PSO) is a common skin disease that affects about 1%–3% of the general population. It is a great medical, social and economic burden since PSO is associated with many comorbidities, of which the most common are cardiometabolic disorders. Psoriatic patients suffer more frequently from obesity, dyslipidemia, atherosclerosis, and nonalcoholic fatty liver disease. Research shows that lipid expression and metabolism disorders are present more often in such patients. This review focuses on a variety of aberrations in lipids in the skin, blood, and adipose tissue in psoriatic patients and their multifactorial impact on the pathogenesis of psoriasis.     

Viscosity-structure relationship of dilute triglycerides’ solutions correlation to retention time in reversed-phase liquid chromatography

The dynamic viscosity (η) of dilute solutions of the trigly-cerides triolein, trilinolein, trimyristin, tristearin and tripalmitin in benzene at temperatures in the range of 25–37°C can be expressed in terms of the viscosity of the solvent (η₀), the triglycerides’ concentration (C) and structural characteristics, such as the length of the carbon chains (CN) and the number of double bonds (DB). The simple empirical equation ln η=k₀+k₁ ln η₀+k₂ CN+k₃ DB+k₄ C satisfactorily describes (within the experimental error of 0.002 cp) the solution viscosity of triglycerides inp-xylene when using the coefficients derived from the benzene solutions. In addition, a relation is derived extending the application of the above-mentioned empirical equation to multicomponent dilute solutions. This last one describes the dilute solution viscosity of natural oils in benzene and agrees with the experimental values. Furthermore, the triglycerides that have equal partition numbers in reversed-phase liquid chromatography (RPLC) exhibit equal values for the solution viscosity. This relationship is similar to the equation expressing the retention time of RPLC in terms of the structure of the solute. Hence, it is suggested that the shape of the solute, which is a significant factor for the solution viscosity of triglycerides, also plays an important role in the retention mechanism of RPLC.     

Synthesis and physicochemical characterization of mixed diacid triglycerides that contain elaidic acid

The synthesis of symmetrical and asymmetrical palmito- and stearo-elaidic triglycerides (PEP, SES, EPP, PEE, ESS, and SEE, in which P=palmitic, S=stearic, and E=elaidic acid) was undertaken to investigate their polymorphism. The chemical pathways and the purification steps, including crystallization and adsorption chromatography, are described. The different chromatographic analyses (gas-liquid chromatography: carbon number profile and fatty acid methyl ester profile, and high-performance liquid chromatography) revealed that the purity of the synthesized products was superior to 99% except for SES (>96%). The thermal behavior, as well as the polymorphism of these triglycerides, has been investigated by means of differential scanning calorimetry and powder X-ray diffraction spectroscopy at variable temperatures. The six compounds crystallize according to a double chainlength packing. The most stable polymorphic form of palmito-elaidic triglycerides belongs to the β′ variety, whereas the stearo-elaidic triglycerides are β stable.     

Filtration in hydrophobic media: 2. A triglyceride partition phenomenon as observed by tangential filtration of butter oil

Having demonstrated a partition of a hydrophobic medium (butter oil) under crossflow filtration and having tentatively explained the phenomenon on stereochemical and saturation basis, the molecular partition was studied by tangential filtration. Under specific hydrodynamic conditions, a filtration phenomenon was demonstrated. The solid fat content (SFC) at 20°C of the fractions obtained was investigated accordingly. When the molecular partition takes place, an SFC divergency between the permeate and the retentate is observed. The amplitude of the divergency depends on experimental conditions.