苯甲酸脂肪酸季戊四醇酯的性能研究

为了进一步提高季戊四醇酯的高温性能,合成了苯甲酸脂肪酸季戊四醇酯,研究了苯甲酸脂肪酸季戊四醇酯的高温抗氧化性能。与脂肪酸(C5酸~C10酸的混合酸)季戊四醇酯相比,高温(200℃)氧化后,苯甲酸脂肪酸季戊四醇酯40℃运动黏度的变化率低~14个百分点,酸值增加值低0.86 mg/g;热分析表明,苯甲酸脂肪酸季戊四醇酯的起始氧化温度有明显地提高;四球试验表明,苯甲酸脂肪酸季戊四醇酯的最大无卡咬负荷(PB值)提高了~14%。说明了苯甲酸脂肪酸季戊四醇酯的润滑性能和高温抗氧化性能明显优于脂肪酸季戊四醇酯。

茶油脂肪酸甲酯的合成

以茶油为原料，甲醇钠作催化剂，经酯交换反应合成制得脂肪酸甲酯。通过正交试验得出其最佳合成条件，并对产物作了ＩＲ和ＧＣ分析。

Biodiesel Production from Crude Jatropha curcas L.Oil with Trace Acid Catalyst

Biodiesel produced from crude Jatropha curcas L.oil with trace sulfuric acid catalyst(0.02%-0.08% oil) was investigated at 135-184 ℃.Both esterification and transesterification can be well carried out simultane-ously.Factors affecting the process were investigated,which included the reaction temperature,reaction time,the molar ratio of alcohol to oil,catalyst amount,water content,free fatty acid(FFA) and fatty acid methyl ester(FAME) content.Under the conditions at 165 ℃,0.06%(by mass) H2SO4 of the oil mass,1.6 MPa and 20:1 methanol/oil ratio,the yield of glycerol reached 84.8% in 2 hours.FFA and FAME showed positive effect on the transesterification in certain extent.The water mass content below 1.0% did not show a noticeable effect on trans-esterification.Reaction kinetics in the range of 155 ℃ to 175 ℃ was also measured.

Identification of the toxic compounds produced by Sargassum thunbergii to red tide microalgae

The inhibitory effects of methanol extracts from the tissues of three macroalgal species on the growths of three marine red tide microalgae were assessed under laboratory conditions.Extracts of Sargassum thunbergii(Mertens ex Roth) Kuntz tissue had stronger inhibitory effects than those of either Sargassum pallidum(Turner) C.Agardh or Sargassum kjellmanianum Yendo on the growths of Heterosigma akashiwo(Hada) Hada,Skeletonema costatum(Grev.) Grev,and Prorocentrum micans Ehrenberg.Methanol extracts of S.thunbergii were further divided into petroleum ether,ethyl acetate,butanol,and distilled water phases by liquid-liquid fractionation.The petroleum ether and ethyl acetate fractions had strong algicidal effects on the microalgae.Gas chromatography-mass spectrometry analyses of these two phases identified nine fatty acids,most of which were unsaturated fatty acids.In addition,pure compounds of four of the nine unsaturated fatty acids had effective concentrations below 5 mg/L.Therefore,unsaturated fatty acids are a component of the allelochemicals in S.thunbergii tissue.

Production of Biodiesel from Sludge Palm Oil by Esterification Process

Sludge palm oil （SPO） is an attractive feedstock and a significant raw material for biodiesel production. The use of SPO can lower the cost ofbiodiesel production significantly. In this study biodiesel fuel was produced from SPO by esterification process using P-toluenesulfonic acid （PTSA） as acid catalyst in different dosages in presence of methanol to convert free fatty acid （FFA） to fatty acid methyl ester （FAME）. Batch esterification process of SPO was carried out to study the influence of PTSA dosage （0.25-10% wt/wt）, molar ratio of methanol to SPO （6：1-20：1）, temperature （40-80 ℃）, reaction time （30-120 min）. The effects of those parameters on the yield of crude biodiesel and conversion of FFA to FAME were monitored. The optimum condition for batch esterification process was 0.75% wt/wt, 10：1 molar ratio, 60 ℃ temperature and 60 minutes reaction time.

Ternary Liquid-Liquid Equilibrium for Systems of Fatty Acid Methyl Ester(Methyl Palmitate/Methyl Stearate)+Ethanol+Glycerol at Atmospheric Pressure

Liquid-liquid equilibrium data of two ternary systems methyl palmitate+ethanol+glycerol and methyl stearate+ethanol+glycerol at(318.2 and 333.2)K and atmospheric pressure were measured. The values of distribution coefficient and selectivity were calculated, which indicates that glycerol can be separated from fatty acid ester by using ethanol as an extraction solvent. The consistency of the isothermal tie-line data were checked by the Othmer-Tobias equation. The correlation coefficients R2 are higher than 0.993,9 for all the fitted curves. The NRTL activity coefficient model was applied to the correlation of the measured tie-line data. The root mean square deviation(RMSD)values are less than 0.007 for all the systems, which shows a good predictive capability of this model for such systems.

Relationship between Ethanol and 2-phenylethanol Stress Tolerance and Fatty Acid Compositions of Saccharomyces cerevisiae

In the present study, we investigated of the ethanol （Eth）, 2-phenylethanol （2-PE） and ethanol/2-phenylethanol （Eth/2-PE） stress tolerance and established relationship between stress tolerance and fatty acid compositions of wine yeast strain S. cerevisiae UCM Y-524 in relation to different cultivation factors. Changes in cell membrane fatty acid profiles studied under different temperature and media. The active oxygenation, semi-aerobic cultivation supplemented Tween 80 conditions were used in different combinations. The concentrations of 2-PE and Eth, the fatty acids methyl esters （FAMES） in the media were measured by GC-MS analyses. 2-PE, Eth, FAMES were identified by NIST02 MS database at the 2-PE and Eth standard solution （Merck, Germany）, bacterial FAMES standard （Supelco）. Palmitoleic and oleic acid were dominated for S. cerevisiae UCM Y-524. The unsaturated/saturated fatty acid （UFA/SFA） ratio was higher than five for S. cerevisiae UCM Y-524 at 14 ~C in simple medium and about more than three for other conditions. It has been found that yeast cells grown in the presence of the 2-PE, Eth and Eth/2-PE appear to increase the amount of unsaturated fatty acids, especially oleic acid, in cellular lipids especially under active oxygenation supplemented with Tween 80. S. cerevisiae UCM Y-524 has a higher tolerance under 2-PE, Eth and Eth/2-PE stress at 28 ~C in a simple medium under aerobic conditions. A higher concentration of unsaturated fatty acids in the membrane S. cerevisiae UCM Y-524 and a lower temperature under aerobic conditions, has been considered to have a positive influence on the excretion of 2-phenylethanol.

Chemical and Microbial Characterization of Feed and Faeces of Two Giant Pill-Millipedes from Forests in the Western Ghats of India

Soil macroinvertebrates are highly diverse and their major ecological service include breakdown of organic matter and in turn improve soil fertility and pill-millipedes are well-known for their significant role in ingestion, disintegration and decomposition of organic matter in soil. This study characterized the feed, the decomposing leaf litter of coconut （Cocos nucifera）, and faeces of two endemic giant pill-millipedes Arthrosphaera disticta and A. fumosa collected from forests of the Western Ghats of India based on chemical features and microbial profile. In both millipedes, electric conductivity and total phosphorus were significantly increased in faeces, while the crude protein, organic carbon, total nitrogen and total phenolics were significantly decreased, as compared to those in feed. Heterotrophic bacteria, actinomycetes, rhizobia and phosphate-solubilizing bacteria were significantly higher in faeces than in feed, while filamentous fungi and yeast substantially decreased in faces compared to feed in both the millipedes. Spectrum of fatty acid methyl esters was considerably different between feed and faeces of both the millipedes. The total saturated fatty acids were higher than the total unsaturated fatty acids in feed as well as faeces, while the ratio of unsaturated/saturated fatty acids decreased from feed to faeces. Dodecanoic and tetradecanoic acids in A. disticta and octadecanoic acid in A. fumosa significantly increased, while （9Z）-octadec-9-enoic and （9E,12E）-octadeca-9,12-dienoic acids in A.. disticta and hexadecanoic, tetracosanoic and （9E,12E）- octadeca-9,12-dienoic acids in A. fumosa significantly decreased in faeces compared to feed, indicating millipede-dependent changes in fatty acids. Icosanoic acid was present in faeces of both the millipedes, and hexadec-9-enoic acid was confined to faeces of A disticta, while pentadecanoic, heneicosanoic, （9Z,12Z,15Z）-9,12,15-octadecatrienoic and eicosenoic acids were confined to faeces of A. fumosa. Pill-millipedes enrich the soil quality by leaf litter conditioning in their gut through specific microbial communities. Fingerprinting of fatty acid methyl esters in faeces of these millipedes reflected the activity of specific microbial population in their guts.