红花油制取共轭亚油酸的研究

以新疆克拉玛依厂的红花油为原料,以丙三醇为溶剂,在KOH的碱性催化作用下,将红花油先转化成亚油酸钾;再利用异构化反应制得浅黄色的共轭亚油酸产品。对产品进行了薄层层析法和紫外分光光度法定性分析,并定量分析了红花油异构化反应的程度。本研究对红花油的深加工将起到很好的推动作用。     

New Bismaleimide-Silica Hybrid Materials: A Critical Assessment of Properties in Correlation with the Method of Synthesis

New hybrid materials have been prepared by sol–gel technique. They have been obtained from bismaleimide monomers either in reaction with N-(3-triethoxysilylpropyl)furan-2-carboxamide monomer, by a Diels–Alder reaction, or in reaction with (3-aminopropyl)triethoxysilane following a Michael addition reaction. The sol–gel process was conducted with or without adding different amounts of tetraethyl orthosilicate. The structures of the obtained compounds have been confirmed by proton nuclear magnetic resonance and Fourier transform infrared spectroscopy. A comparative study between Diels–Alder- and Michael addition-type products regarding their thermal and mechanical properties was also conducted for samples as obtained from synthesis. The thermoreversible character of the Diels–Alder hybrid materials has been demonstrated with the aids of differential scanning calorimetry and attenuated total reflectance Fourier transform infrared spectroscopy, the results from both methods being in good agreement with each other, and with literature data. The morphology of hybrid materials was studied by the atomic force microscopy, optical microscopy for three different stages: initial (24°C), at heating (150°C), and after cooling at 24°C, and scanning electron microscopy. All data confirmed the driving force for the dispersion of the Si-containing aggregates in the Michael addition series is the dynamic evolution of the sol–gel process, whereas the Diels–Alder series behavior is ruled by the thermoreversible character of the Diels–Alder cycloaddition.     

A kinetic model of the cycloaddition reactions between cyclopentadiene and 1,3-butadiene for synthesis of 5-vinyl-2-norbornene

Under high temperature and pressure, a continuous tubular reactor was successfully utilized to investigate the kinetics of 5-vinyl-2-norbornene (VNB) production. The process involved multiple cycloaddition reactions between cyclopentadiene (CPD) and 1,3-butadiene (BD). The results, spanning a wide range of operating conditions, indicate that higher temperature (180°C) and proper residence time (72 min) were conducive to efficient synthesis of VNB. The apparent kinetic parameters, including activation energies and pre-exponential factors, were acquired by fitting experimental data under integral operating conditions. The kinetic model was proven effective from a practical point of view in predicting the concentration changes of each product in the range 140 to 180°C and 30 to 80 wt.% concentration. This work provides a solid basis for the optimization of the VNB synthesis process.     

Chemoselectivity in the Pd‐Catalyzed Cyclization of 1,6‐Enynes and Proof of the Relative Configuration of the New Stereogenic Centers

The dimerization of dienyne 6 with a palladole catalyst readily provides the bicyclic enyne rac‐ 7 . A second cyclization of the 1,6‐enyne substructure in rac‐ 7 works best with a hydropalladation catalyst and delivers rac‐ 8 . Diels‐Alder reactions of the latter finally lead to a crystalline product rac‐ 12 . A crystal structure analysis of rac‐ 12 allowed the determination of the relative configuration of all stereogenic centers formed in the dimerization of 6 .     

Transition‐metal trifluoromethane‐sulphonates‐recyclable catalysts for the synthesis of branched fatty derivatives by Diels‐Alder reactions at unsaturated fatty esters

Diels‐Alder reactions of conjugated linoleic acid ethyl ester (1) with different quinones and with a variety of α/βunsaturated aldehydes and ketones are described in this paper. Using Sc(OTf)₃ or Cu(OTf)₂ as catalysts the reactions can be carried out at 25—40 °C with good yields. For the first time in oleochemistry it is possible to prepare Diels‐Alder cycloadditions with catalyst concentrations of 10 mol‐% instead of stoichiometric amounts of Lewis acids. Furthermore, the reaction time was partly shortened drastically. The catalyst Sc(OTf)₃ can be removed by a simple extraction of the organic layer with water. After evaporation of the aqueous phase to dryness the catalyst can be reused without loss of yield.     

Quality of Sunflower Oil Obtained in the Main Producing Region of Brazil: Adherence to the Codex Alimentarius

The objective of this work was to evaluate the quality of the oil extracted from sunflower achenes grown in Campo Novo de Parecis, the main producing region of Brazil, to optimize its use by the processing and food industries. In addition, the fatty acid profiles of the oil were checked for their adherence to the CODEX STAN 210–1999. Traditional and high-oleic genotypes were grown between 2014 and 2017 during trials with a randomized complete block experimental design with four replications. The contents of oleic, linoleic, palmitic, and stearic acids were determined using gas chromatography. The fatty acid profiles of traditional genotypes were observed to be outside the ranges established by the CODEX, with an oleic acid content above 39.4% and linoleic, palmitic, and stearic acid values lower than 48.3%, 2.7%, and 5.0%, respectively, as well as high-oleic sunflower oil with a stearic acid content of less than 2.6%. The availability of this information can, on the one hand, positively impact industries and encourage the use of better quality raw materials that are more technologically and nutritionally adequate. On the other hand, the commercialization of sunflower oil with a fatty acid profile outside the ranges established by CODEX can be difficult, because the contents are out of specification due to the climatic conditions in the cropping region.     

Influence of Temperature on the Fatty Acid Composition of the Oil From Sunflower Genotypes Grown in Tropical Regions

The influence of temperature on the fatty acid composition of the oils from conventional and high oleic sunflower genotypes grown in tropical regions was evaluated under various environmental conditions in Brazil (from 0° S to 23° S). The amounts of the oleic, linoleic, palmitic and stearic fatty acids from the sunflower oil were determined using gas chromatography (GC). The environment exhibited little influence on the amounts of oleic and linoleic fatty acids in high oleic genotypes of sunflower. In conventional genotypes, there was broad variation in the average amounts of these two fatty acids, mainly as a function of the minimum temperature. Depending on the temperature, especially during the maturation of the seeds, the amount of oleic acid in the oil of conventional sunflower genotypes could exceed 70 %. Higher temperatures led to average increases of up to 35 % for this fatty acid. Although the minimum temperature had the strongest effect on the fatty acid composition, locations at the same latitude with different minimum temperatures displayed similar values for both oleic acid and linoleic acid. Furthermore, minimum temperature had little influence on the amounts of palmitic and stearic fatty acids in the oil.     

Structure Identification of Triacylglycerols in the Seed Oil of Momordica Charantia L. Var. Abbreviata Ser.

Triacylglycerols (TGs) in the seed oil of Momordica charantia L. var. abbreviata Ser. (MCV) were separated by non-aqueous reversed-phase (NARP)-HPLC. Many of the TGs contain two different fatty acyl chains, such as palmitic (P), stearic (S), oleic (O), linoleic (L), and conjugated linolenic acid (CLn). Seven pairs of AAB/ABA-type TGs might present in the seed oil of MCV, namely CLnCLnP/CLnPCLn, CLnCLnS/CLnSCLn, CLnCLnO/CLnOCLn, CLnCLnL/CLnLCLn, SSCLn/SCLnS, OOCLn/OCLnO and LLCLn/LCLnL. The positional isomers of a AAB/ABA-type TGs pair yielded mass spectra showing a significant difference in relative abundance ratios of the fragment ions [AA]⁺ to [AB]⁺, which were produced by preferred losses of the fatty acid from the 1/3-position compared to the 2-position of the glycerol backbone. The precise stereospecific structures of the predominant regioisomers of TGs in AAB/ABA pairs were identified by atmospheric pressure chemical ionization mass spectrometry (APCI-MS) according to the special relative abundance ratios of the fragment ions [AA]⁺ to [AB]⁺. TGs with CLn occupying the sn-2 position in seven pairs of AAB/ABA might be major constituents of the oil, such as CLnCLnS, LCLnL, CLnCLnP, and so on. Some of the TGs which were isolated and collected as fractions from the seed oil of MCV by NARP-HPLC were further analyzed by ¹³C-NMR. ¹³C-NMR data of type-AAA TGs containing α-eleostearic acyl have been complemented.     

The Utilization of the Acyl-CoA and the Involvement PDAT and DGAT in the Biosynthesis of Erucic Acid-Rich Triacylglycerols in Crambe Seed Oil

The triacylglycerol of Crambe abyssinica seeds consist of 95 % very long chain (>18 carbon) fatty acids (86 % erucic acid; 22:1^?13) in the sn‐1 and sn‐3 positions. This would suggest that C. abyssinica triacylglycerols are not formed by the action of the phospholipid:diacylglycerol acyltransferase (PDAT), but are rather the results of acyl‐CoA:diacylglycerol acyltransferase (DGAT) activity. However, measurements of PDAT and DGAT activities in microsomal membranes showed that C. abyssinica has significant PDAT activity, corresponding to about 10 % of the DGAT activity during periods of rapid seed oil accumulation. The specific activity of DGAT for erucoyl‐CoA had doubled at 19 days after flowering compared to earlier developmental stages, and was, at that stage, the preferred acyl donor, whereas the activities for 16:0‐CoA and 18:1‐CoA remained constant. This indicates that an expression of an isoform of DGAT with high specificity for erucoyl‐CoA is induced at the onset of rapid erucic acid and oil accumulation in the C. abyssinica seeds. Analysis of the composition of the acyl‐CoA pool during different stages of seed development showed that the percentage of erucoyl groups in acyl‐CoA was much higher than in complex lipids at all stages of seed development except in the desiccation phase. These results are in accordance with published results showing that the rate limiting step in erucic acid accumulation in C. abyssinica oil is the utilization of erucoyl‐CoA by the acyltransferases in the glycerol‐3‐phosphate pathway.     

The Protective Mechanism of Deuterated Linoleic Acid Involves the Activation of the Ca2+ Signaling System of Astrocytes in Ischemia In Vitro

Ischemia-like (oxygen-glucose deprivation, OGD) conditions followed by reoxygenation (OGD/R) cause massive death of cerebral cortex cells in culture as a result of the induction of necrosis and apoptosis. Cell death occurs as a result of an OGD-induced increase in Ca²⁺ ions in the cytosol of neurons and astrocytes, an increase in the expression of genes encoding proapoptotic and inflammatory genes with suppression of protective genes. The deuterated form of linoleic polyunsaturated fatty acid (D4-Lnn) completely inhibits necrosis and greatly reduces apoptotic cell death with an increase in the concentration of fatty acid in the medium. It was shown for the first time that D4-Lnn, through the activation of the phosphoinositide calcium system of astrocytes, causes their reactivation, which correlates with the general cytoprotective effect on the cortical neurons and astrocytes in vitro. The mechanism of the cytoprotective action of D4-Lnn involves the inhibition of the OGD-induced calcium ions, increase in the cytosolic and reactive oxygen species (ROS) overproduction, the enhancement of the expression of protective genes, and the suppression of damaging proteins.     

甲醇低压羰基合成醋酸铑/铱-碘催化剂的作用机理探讨

介绍了甲醇低压羰基合成醋酸工艺中铑-碘催化剂体系、铱-碘催化剂体系以及改良后催化剂体系在反应系统中的作用机理,总结了其在实际生产过程中不同的控制原理和步骤,能够更好地分析和解决生产中出现的问题。通过对比分析可以看出,工业生产采用铱-碘催化剂体系比铑-碘催化剂体系有更多的优点,是甲醇低压羰基合成醋酸工艺关注的重点。     

Effect of tween series on growth and cis-9, trans-11 conjugated linoleic acid production of Lactobacillus acidophilus F0221 in the presence of bile salts

Cis-9, trans-11 conjugated linoleic acid (c9, t11 CLA) producing bacteria have attracted much attention as novel probiotics which have shown beneficial effects on host health. However, bile salts are able to inhibit bacterial growth and c9, t11 CLA production. For recovering growth and c9, t11 CLA production of Lactobacillus acidophilus F0221 in the presence of bile salts, Tween series (Tween 20, Tween 40, Tween 60 and Tween 80) were added in growth culture containing 0.3% oxgall. Results showed that the viable counts were significantly (P < 0.05) recovered to 8.58-8.75 log CFU/mL in the presence of all Tween treatments. However, recovery of c9, t11 CLA production was only demonstrated in the presence of Tween 80 (72.89 μg/mL). Stepwise increasing oxgall in a concentrations range from 0.1% to 0.9% according to human intestinal physiological environments, Tween 80 still showed significant (P < 0.05) recovery ability on growth (8.91-8.04 log CFU/mL) and c9, t11 CLA (69.22-34.27 μg/mL) production. The effect of Tween 80 on growth and production was also investigated in the presence of different types of bile salts (sodium salts of cholic acid (CA), deoxycholic acid (DCA), chendeoxycholic acid (CDCA), glycocholic acid (GCA) and taurocholic acid (TCA)). Results showed that Tween 80 could significantly (P < 0.05) recover c9, t11 CLA production in the presence of all types of bile salts, but the Tween 80 could only significantly (P < 0.05) recover viable counts of the strain in the presence of CA, DCA and CDCA. This recovery ability could be attributed to the protection of leakage of intracellular material. Additionally, although bile salts inhibited growth and c9, t11 CLA production by the growing cell, it promoted the c9, t11 CLA production by the resting cell.