Epoxidation of Unsaturated Fatty Acid Methyl Esters in the Presence of SO_3H-functional Brφnsted Acidic Ionic Liquid as Catalyst

The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst.

Boosted Biodegradability and Tribological Properties of Mineral Base Oil by Methyl Diethanolamine Fatty Acid Esters

Methyl diethanolamine fatty acid esters, viz. methyl diethanolamine octanoate and methyl diethanolamine oleate,were prepared. Their impacts on the biodegradability and tribological properties of mineral base oil 400 SN were evaluated by a tester for fast evaluating the biodegradability of lubricants and by a four-ball tester, respectively. The results showed that methyl diethanolamine octanoate and methyl diethanolamine oleate both could markedly promote the biodegradation of the oil and improved its tribological properties. The improvement of biodegradability was attributed to the enhanced growth and quantity of microbes by methyl diethanolamine fatty acid esters. The worn surfaces were analyzed by a scanning electron microscope(SEM) equipped with an energy dispersive spectrometer(EDS) and an X-ray photoelectron spectroscope(XPS). The results indicated that the enhancement of friction-reducing and anti-wear properties of the mineral oil was attributed to the formation of complicated boundary lubrication films composed of species such as Fe_2O_3, Fe_3O_4 and organic nitrogen-containing compounds with a structure of –C-N-or R-NH_2.

Effects of Yttrium Doping on the Performance of Ru-Based Catalysts for Hydrogenation of Fatty Acid Methyl Ester

The highly dispersed supported ruthenium-yttrium (Ru-Y) bimetallic catalysts were prepared by impregnation method and their catalytic performance for hydrogenation of ester was fully investigated. The catalyst was characterized by X-ray diffraction and field emission scanning electron microscopy. The results show that the average particle diameter of the bimetallic crystallites was less than 10 nm. The effects of the reaction temperature, the hydrogen pressure, the amount of catalyst and the proportion of yttrium in catalyst on the hydrogenation of ester were studied. The experimental results show that the introduction of yttrium not only changed the chemical and textural properties of ruthenium-based catalyst but also controlled the formation of Ru-Y alloy. The Ru-Y catalyst (Ru-2%Y/TiO2) exhibited high catalytic activity and good selectivity towards the higher alcohols. Under optimal reaction conditions of 240°C and 5 MPa hydrogen pressure, the conversion of palm oil esters was above 93.4% while the selectivity towards alcohol was above 99.0%.

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.

Determination of the Fatty Acid Profile of Breast Milk from Nursing Mothers in Bungoma County, Kenya

The fatty acid profile in breast milk of nursing mothers who participated in a Cohort for Vitamin A (COVA) study at the fourth and ninth month of lactation was investigated. Breast milk samples were collected by manual expression and stored at - 20°C until analysis. The fat was extracted from the milk and methylated using the American Oil Chemists’ Society (AOCS) Official Methods with modifications. The separation, identification and quantification of the fatty acid methyl esters was performed by gas chromatography coupled with mass spectrometry (GC-MS). Fat contents of human milk increased significantly between the fourth and ninth month of lactation 0.38 and 1.21 mg·mL-1 respectively;P 0.05) than the average percent of the total unsaturated FAs (48.93%). Similarly, at the 9th month the percentage average of the total saturated fatty acids (15.18%) was significantly lower (P < 0.05) than the average percent of the total unsaturated FAs (31.05%). The results obtained in this study demonstrated that the fat content in breast milk significantly increased in the 9th compared to the 4th month of lactation. The fatty profile was also significantly different with the omega 6 being the dominant at the 9th month compared with the omega - 9 being dominant at the 4th month of lactation.

Production of biodiesel from palm fatty acid distillate using sulfonated-glucose solid acid catalyst:Characterization and optimization

A palm fatty acid distillate （PFAD） has been used for biodiesel production. An efficient sulfonated-glucose acid catalyst （SGAC） was prepared by sulfonation to catalyze the esterification reaction. The effect of three variables i.e. methanol-to-PFAD molar ratio, catalyst amount and reaction time, on the yield of PFAD esters was studied by the response surface methodology （RSM）. The optimum reaction conditions were： 12.2：1 methanol-to- PFAD molar ratio, 2.9% catalyst concentration and 134 rain of time as predicted by the RSM. The reaction under the optimum conditions resulted in 94.5% of the free fatty acid （FFA） conversion with 92.4% of the FAME yield. The properties of the PFAD esters were determined according to biodiesel standards.

In Situ Transesterification of Wet Marine and Fresh Water Microalgae for Biodiesel Production and Its Effect on the Algal Residue

This article reports a high yielding technique of synthesizing zirconium dodecyl sulphate (“ZDS”) for in situ transesterification of Nannochloropsis occulata and Chlorella vulgaris for fatty acid methyl ester (FAME) production. ZDS produced a significantly higher FAME yield in N. occulata than in C. vulgaris (p = 0.008). The varying performance of ZDS in the two species could be due to their different cell wall chemistries. Sodium dodecyl sulphate (SDS) in H2SO4 for FAME enhancement from the two species was also studied. Treatment with SDS in H2SO4 increased the FAME production rate in both species. Residual protein content after the in situ transesterification in C. vulgaris and N. occulata reduced respectively by 6.5% and 10%. The carbohydrate content was reduced by 71% in C. vulgaris and 65% in N. occulata. The water tolerance of the process when using H2SO4, with or without SDS, was evaluated by hydrating the two species with 10% - 30% distilled water (w/w dry algae). The FAME concentration began to diminish only at 30% water content in both species. Furthermore, the presence of a small amount of water in the biomass or methanol increased the lipid extraction efficiency, improving the FAME yield, rather than inhibiting the reaction.

Ethanol Evaporation Characteristics of the Blends of Fatty Acid Methyl Ester and Ethanol

The evaporation characteristics of fatty acid methyl ester(FAME)mixed with four concentrations of ethanol at 873 K and normal atmospheric pressure are studied herein.FAME is used as base oils,and et hanol mass fractions vary from 10%,20%,30%to 40%。The experimental results show that the evaporation process of the binary component droplets of FAME-ethanol can be divided into two stages:a fuctuation evaporation stage,and an equilibrium evaporation stage.In these four concentration gradients,micro-explosions occur in the droplet evaporation process.The fuctuation evaporation stage is divided into two stages:a strong fuctuation stage and a weak fluctuation stage.After the micro-explosion,there is still a small amount of ethanol in the droplet.Due to the surface tension of the droplet,a small amount of ethanol cannot make the droplet violently fuctuate.The results show that the earlier the droplet micro-explosion occurs,the more intense it is,and the shorter the lifetime of the droplet is.Different concentrations of ethanol have different improvements in droplet evaporation characteristics.Generally,the higher the ethanol concentration is,the shorter the lifetime of the droplet is.However,increasing the ethanol concentration from 20%to 30%has the most obvious effect on the lifetime of the droplet.

NiMoRe/HZSM-5催化剂的制备及其催化脂肪酸甲酯加氢脱氧

使用浸渍法制备了5 kg NiMoRe/HZSM-5催化剂,结合X射线衍射(XRD)、扫描电子显微镜(SEM)、电感耦合等离子原子发射光谱(ICP-OES)等表征手段对催化剂进行理化性质分析,并对该催化剂用于硬脂酸甲酯加氢脱氧反应的最佳条件进行探究。研究结果表明:相比3种商用催化剂,NiMoRe/HZSM-5中金属Ni具有较小颗粒,且分散均匀,BET比表面积(S_(BET))更大,为239.1 m^(2)/g,具有更好的催化活性。在温度260℃、0.3 g催化剂用量、反应时间4 h、初始H 2压力3 MPa的最优反应条件下,原料转化率和烷烃选择性均为100%,且催化剂稳定性较佳,第5次循环原料转化率仍高达96.1%,加氢脱氧(HDO)反应的选择性(S HDO/DCO),即HDO反应与脱羧脱羰(DCO)反应的比值由1.2降至0.56。将催化剂NiMoRe/HZSM-5用于脂肪酸甲酯无溶剂条件下的加氢脱氧反应放大实验后进行中试,采用2.8 L固定床对25 kg脂肪酸甲酯进行连续加氢性能评价,经过15循环后脂肪酸甲酯的转化率达到98%。

丙磺酸型碗状碳微球制备及在餐厨废油酯交换反应中的性能研究

以碗状碳微球(BHC)为载体,合成了以烷基为磺酸基键合位点的丙磺酸型碗状碳微球(PA-CBHC-Si)。X射线光电子能谱仪、扫描电子显微镜和傅里叶变换红外光谱分析表明,三步改性分别逐步丰富BHC表面羧基(—COOH)、巯基(—SH)、磺酸基(—SO_(3)H)官能团含量,且改性过程保留了载体的原始形貌。PA-CBHC-Si的酸密度高达8.5mmol/g,活性中心—SO_(3)H于300℃开始分解,具有良好的热稳定性。PA-CBHC-Si可作为煎炸废油与甲醇酯交换反应的催化剂,醇油摩尔比为16∶1,剂油比为0.02的催化体系于130℃反应4h,脂肪酸甲酯产率为84.53%。

气相色谱法测定调制羊奶粉中37种脂肪酸

建立了气相色谱法(Gas Chromatography,GC)同时测定调制羊奶粉中37种脂肪酸的分析方法。样品经氨水水解,用乙醚-石油醚混合液(1∶1,v/v)提取,提取物经2%氢氧化钠-甲醇溶液皂化,15%三氟化硼-甲醇溶液甲酯化,正庚烷提取后用GC测定。37种脂肪酸在各自的质量浓度范围内线性关系良好(R2>0.995),方法检出限为0.002~0.006 g/100 g,方法定量限为0.01~0.03 g/100 g。质控样的平均加标回收率为83.3%~108.5%,相对标准偏差为0.9%~5.6%(n=6)。该方法操作简便、准确可靠,用于测定市场购买的16组调制羊奶粉,结果发现市售调制羊奶粉中脂肪酸的组成及含量存在差异。

气相色谱-氢火焰离子化测定脂肪酸甲酯的响应机理与定量规律

针对国内外现行标准中气相色谱-氢火焰离子化检测器(gas chromatography-flame ionization detector,GCFID)测定脂肪酸甲酯(fatty acid methyl esters,FAME)定量方法的不足,本实验通过理论推导和实验验证,从仪器、色谱柱、分流比、标准物质方面系统研究利用GC-FID分析37种FAME的响应规律、理论模型及实验干扰因素,提出“质量系数”和“关联因子”概念,揭示实验关联因子(experimental relevance factors,FF_(E))和理论关联因子(theoretical relevance factors,FF_(T))的函数关系和等值性条件,并经多个实验证实了关联因子的稳定性,发现当脂肪酸碳数大于10时,可充分利用理论质量系数(theoretical quality coefficient,QC_(T))和FFT对FAME进行相对或绝对定量;当脂肪酸碳数小于10时,可以通过现配FAME标准物质等方法精确测定实验质量系数(experimental quality coefficient,QC_(E))和实验关联因子FFE,并用此校正FAME的量进行定量,不仅能够提高定量结果的准确性,而且能够增加标准物质的使用时效以及节省标准物质的使用量。

固相萃取-气相色谱-串联质谱技术测定船用残渣燃料油中酚类及脂肪酸甲酯类化合物

本文利用乙酸银修饰的氧化铝-硅胶材料制备固相萃取柱对船用残渣燃料油样品进行净化分离,结合气相色谱-串联质谱技术,使用DB-35 MS UI色谱柱分离,多反应监控模式,内标法定量测定酚类及脂肪酸甲酯(FAME)类化合物。对影响酚类和FAME类化合物的进样方式、萃取溶剂的选择、固相萃取柱类型的选择以及淋洗和洗脱条件进行了优化,建立了船用残渣燃料油中酚类及FAME类化合物的测定方法。方法在浓度0.05~2.5μg/mL范围线性良好,具有检出限(0.1~1.2 mg/kg)和定量限(0.3~4.0 mg/kg)低,稳定性好和萃取效率高,以及基质效应不显著等优势。通过用不含目标物的空白燃料油配制0.10、0.50、2.50 mg/L浓度水平的试样考察方法的可靠性,获得满意的回收率(85.5%~115.4%)和相对标准偏差(RSD≤6.2%)。实验结果表明,建立的方法可实现船用残渣燃料油中酚类及FAME类化合物的有效检测。另外,劣质船用燃油存在不少的酚类和FAME类物质,高浓度苯酚、甲酚、二甲酚、对枯基苯酚、脂肪酸甲酯等物质可能是导致船舶油泵损坏的重要原因。

蛋白核小球藻原位催化制备生物柴油的研究

化石燃料是全球能源供应的主要来源,在过去的几十年里,由于人口和能源需求的增加,导致能源消耗和CO_(2)排放量迅速增加,加剧了全球气候变化。利用生长迅速、含油量高、对环境友好的蛋白核小球藻(Chlorella pyrenoidosa)催化转化生物柴油具有很大发展潜力,可以实现“碳中和”及可持续发展。传统的两步酯交换法制备生物柴油在经济环境上是不可行的,脱水干燥和脂质提取过程消耗了大量能源和成本,采用“一步”原位酯交换方法替代传统的两步酯交换将微藻转化为低成本高附加值产品,可以实现高生物柴油产率及高C16、C18脂肪酸甲酯组分含量,产生高质量的生物柴油,具有生态和经济效益。

常用植物油中棉籽油掺假鉴别研究

目的:建立气相色谱-质谱法鉴别植物油中掺假棉籽油。方法:样品经由氢氧化钠-甲醇溶液甲酯化,经离心过滤后由气相色谱-质谱法测定。结果:检出限和定量限分别为0.775 μg·g^(-1)和2.557 μg·g^(-1),回收率在92.55%~94.67%;大豆油、葵花籽油、菜籽油、芝麻油的最低鉴别掺假比例为3%(质量比),花生油最低鉴别掺假比例为15%(质量比)。结论:该方法快速、简便,适用于植物油中棉籽油掺假的鉴别。

溶剂分离法提取生物柴油中的不饱和脂肪酸甲酯

为了降低生物柴油的冷凝点,采用溶剂分离法提取生物柴油中的不饱和脂肪酸甲酯,重点考察了醇的种类、溶剂的用量、冷冻温度和过滤方式对分离效果的影响。结果表明:乙醇的用量为原料质量的2~3倍,冷冻温度-15℃,压滤法过滤,最高可得到96.9575%的不饱和脂肪酸甲酯含量和86.92%的得率。

Relationship Between Microbial Community and Soil Properties During Natural Succession of Abandoned Agricultural Land

The changes of microbial biomass carbon (MBC) and nitrogen (MBN) and microbial community in the topsoil of the abandoned agricultural land on the semi-arid Loess Plateau in China during the natural succession were evaluated to understand the relationship between microbial community and soil properties. MBC and MBN were measured using fumigation extraction, and microbial community was analyzed by the method of fatty acid methyl ester (FAME). The contents of organic C, total N, MBC, MBN, total FAME, fungal FAME, bacterial FAME and Gram-negative bacterial FAME at the natural succession sites were higher than those of the agricultural land, but lower than those of the natural vegetation sites. The MBC, MBN and total FAME were closely correlated with organic C and total N. Furthermore, organic C and total N were found to be positively correlated with fungal FAME, bacterial FAME, fungal/bacterial and Gram-negative bacterial FAME. Natural succession would be useful for improving soil microbial properties and might be an important alternative for sustaining soil quality on the semi-arid Loess Plateau in China.

Effect of natural and synthetic antioxidants on oxidative stability of FAMEs obtained from hevea brasiliensis

Biodiesel(fatty acid alkyl esters),an alternate to fossil fuel,has the tendency of autoxidation and hence requires antioxidants for long term storage.The influence of synthetic and natural antioxidants on the oxidative stability was analysed for fresh FAMEs(fatty acid methyl esters)obtained from hevea brasiliensis at 140 C.Higher activity was observed for synthetic antioxidants following the order of GA】BHT】DTBP】Q】GT-M】PH-M】GT-C,whereas the oxidative stability of stored FAMEs samples measured at 110 C reveals a nearly inverse trend.Storage stability was tested for the FAMEs obtained from hevea brasiliensis stored at 30 C,after addition of synthetic and natural antioxidants—butylated hydroxytoluene(BHT),2,6-di-tert-butylphenol(DTBP),quercetin(Q),gallic acid(GA),methanol extracts from green tea(GTM),pomegranate hull(PH-M),and chloroform extract of green tea(GT-C).Antioxidant activities above 1500 ppm was in the order of DTBP】BHT】GA】GT-C】GT-M】Q】PH-M.Synthetic antioxidants have been found more efficient to improve the storage stability of FAMEs obtained from hevea brasiliensis.DTBP in particular has the highest protection factor.

Comparative characterization of Jatropha,soybean and commercial biodiesel

Oil was extracted from seeds of Jatropha Curcas,in high yields(up to 40% by weight).The extracted Jatropha oil was converted in a laboratory reactor to biodiesel by transesterification.Analysis of Jatropha oil and Jatropha biodiesel by GC/MS and GC/SIMDIS showed that Jatropha oil could be readily converted to a biodiesel product through NaOH catalyzed transesterification.The resulting biodiesel has desirable properties such as high cetane number and low flash point,which are major improvements over the properties of commercial biodiesel fuels.

<i>In Vitro</i>Anti-Diabetic Activities and Phytochemical Analysis of Bioactive Fractions Present in <i>Meriandra dianthera, Aloe camperi</i>and a Polyherb

This paper reports the in vitro anti-diabetic profile of certain medicinal plants traditionally used in Eritrea for the management of type 2 diabetes. The crude methanolic extracts and fractions of Meriandra dianthera, Aloe camperi, a Polyherb and their fractions were investigated. The in vitro screening of the crude extracts has generally elicited a dose dependent α-glucosidase and α-amylase inhibition activities. M. dianthera displayed the highest α-glucosidase inhibitory activity (IC50: 0.074 ± 0.032 mg/mL) at the highest concentration tested (0.800 mg/mL) relative to A. camperi, the Polyherb and Acarbose (IC50: 0.37 ± 0.052, 0.56 ± 0.024 and 0.55 ± 0.029 respectively). The α-glucosidase inhibition activities of A. camperi and M. dianthera, except for the Polyherb and Acarbose, were significantly different (P < 0.05) at various ranges of concentrations (0.025 - 0.800 mg/mL). The percentage α-amylase inhibitions of M. dianthera, A. camperi, the Polyherb and Acarbose, at the highest concentrations (0.800 mg/mL), were 78.3%, 15.9%, 16.4%, and 82.9% respectively. A. camperi and the Polyherb displayed lower α-amylase inhibitory activities (IC50: 1.72 ± 0.06 and 2.57 ± 0.07 mg/mL respectively) compared to Acarbose and M. dianthera (IC50: 0.31 ± 0.01 and 0.43 ± 0.02 mg/mL respectively). For the α-amylase inhibition activity, even at lower concentrations (0.025 mg/mL), there were statistically significant differences (P < 0.01) among the values generated for all the extracts. The in vitro anti-diabetic screening of the fractions, at 0.800 mg/ml, displayed characteristic enzyme inhibition activities. Generally, the non-polar fractions showed higher enzyme inhibitory activities compared to the polar fractions. The most bioactive non-polar fractions, thus, were subjected to GC-MS analysis and presented various essential oils, fatty acid methyl esters (FAMEs) and benzoic acid derivatives in those plants.