Essential Oil and Antimicrobial Evaluation of the Pistacia eurycarpa

The compositions of microdistilled and hydrodistilled essential oils of the mastix ofPistacia eurycarpaYalt. (Anacardiaceae) were compared. The essential oils were analyzed by GC/MS:- andbeta;-pinenes were found as the major constituents. The antimicrobial activity of the hydrodistilled oil was determined due to the ethnomedical uses of the oleo-gum resin on skin diseases.     

Pyrolysis Analysis and Kinetics of Crude Oils

This research presents the results of an experimental study on the determination of pyrolysis behaviour and kinetics of six crude oils by differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). Crude oil pyrolysis indicated two main temperature ranges where loss of mass was observed. The first region between ambient to 400°C was distillation. The second region between 400 and 600°C was visbreaking and thermal cracking. Arrhenius-type kinetic model is used to determine the kinetic parameters of crude oils studied. It was observed that as crude oils gets heavier (°API decreases) cracking activation energy increases. Activation energy of cracking also show a general trend with asphaltene content. This revised version was published online in July 2006 with corrections to the Cover Date.     

Multivariate monitoring of soybean oil ethanolysis by FTIR

In this work, an analytical procedure was developed to monitor the ethanolysis of degummed soybean oil (DSO) using Fourier-transformed mid-infrared spectroscopy (FTIR) and methods of multivariate analysis such as principal component analysis (PCA) and partial least squares regression (PLS). The triglycerides (reagents) and ethyl esters (products) involved in ethanolysis were shown to have similar FTIR spectra. However, when the FTIR spectra derived from seven standard mixtures of triolein and ethyl oleate were treated by PCA at the region that represents the CO stretching vibration of ester groups (1700-1800 cm⁻¹), only two principal components (PC) were shown to capture 99.95% of the total spectral variance (92.37% for the former and 7.58% for the latter PC). This observation supported the development of a multivariate calibration model that was based on the PLS regression of the FTIR data. The prevision capability of this model was measured against 40 reaction aliquots whose ester content was previously determined by size exclusion chromatography. Only small discrepancies were observed when the two experimental data sets were treated by linear regression (R²=0.9837) and these deviations were attributed to the occurrence of non-modeled transient species in the reaction mixture (reaction intermediates), particularly at short reaction times. Therefore, the FTIR/PLS model was shown to be a fast and accurate method to predict reaction yields and to follow the in situ kinetics of soybean oil ethanolysis.     

Adsorption of crude oil on anhydrous and hydrophobized vermiculite

This publication reports the adsorption of crude oil on vermiculite samples, expanded and hydrophobized with carnauba (Copernícia Cerífera) wax. The adsorption studies were performed by using columns filled with the vermiculite matrices and by dispersion of the vermiculite samples in an oil-water (50 ppm of oil) emulsion. The hydrate vermiculite exhibits a very low adsorption capacity against crude oil. On the other hand, anhydrous (expanded) and hydrophobized matrices show a high adsorption capacity. The 10% hydrophobized matrix show a 50% increased adsorption capacity, in comparison with the expanded one. For adsorption performed in the water-oil emulsion, saturation of the solid hydrophobized matrix is achieved after 60 min. The hydrophobized samples exhibit adsorption factors in the 0.7-1.0 range.     

生姜挥发性成分的分析

本文采用水蒸气蒸馏法提取了生姜挥发性成分，并用GC／MS方法对提取的挥发性成分进行了鉴定。共鉴定了30种化学成分，并进行了讨论。     

阳离子交换柱分离-导数光度法测定原油中钒

以 5Br PADAP为显色剂 ,用阳离子交换柱分离干扰离子 ,在波长 6 30nm采用一阶导数光度法测定原油中钒 ,方法灵敏度高 ,摩尔吸光系数为 3.0× 10 5L·mol- 1·cm- 1,较其它光度法测定钒的摩尔吸光系数提高 1～ 2个数量级。对实际样品进行分析并做加标回收试验 ,钒的回收率在97.5 %～ 10 4 .0 %。与ICP AES方法进行对照试验 ,结果相吻合。     

Screening the origin and weathering of oil slicks by attenuated total reflectance mid-IR spectrometry

The combination of attenuated total reflectance-fourier transform mid-infrared spectrometry (ATR-FTMIR) and multivariate pattern recognition is presented as a fast and convenient methodology to ascertain the source product an oil slick comes from and to evaluate the extent of its weathering. Different types of hydrocarbons (including crude oils, several heavy distillates and the Prestige's heavy fuel oil) were spilled on metallic containers designed ad hoc and their fate monitored by ATR-FTMIR. Not only environmental conditions were considered for weathering but artificial IR- and UV-irradiation. Pattern-recognition studies revealed that the different hydrocarbons clustered at different locations on the score plots and that the samples corresponding to each oil became ordered according to the extent of their weathering. Among them, fuel oil samples coming from the recent disaster of the Prestige tanker off the Galician shoreline showed a distinctive behaviour. Comparison of natural-, IR- and UV-weathering of a crude oil showed that IR solar radiation can be important in oil-weathering, in addition to broadly-reported UV degradation.     

核磁共振研究MoDTP及其与ZnDTP的相互作用和机理

利用31P核磁共振谱研究了MoDTP及其与ZnDTP的相互作用，并用Timken实验机、SEM、DSC法分别考察了MoDTP与ZnDTP复合对润滑油板压、抗磨损及抗氧化性能的影响。结果表明：MoDTP与ZnDTP分子间有烷基和／或烷氧基的相互转换；二者并用在综合性能上有较好的协同增效作用。在此基础上，提出了MoDTP与ZnDTP协同增效作用的机理。     

Influence of extractions on physicochemical characterization and bioactivity of Piper nigrum oils: Study on the non-isothermal decomposition kinetic

Black pepper oils have been investigated frequently in the recent years. However, there is a significant variation in physicochemical properties and bioactivity of oils depended on extraction techniques. In this study, the systemic investigation of four various extraction methods was performed to evaluate the physicochemical characterizations, antioxidant and antibacterial activity. The investigation of ¹H NMR, FTIR and UV–Vis spectra confirmed presence of non-volatile components in oils extracted through supercritical CO₂ and hexane-soaking extractions which induced their typical thermal properties. The isothermal behaviour of extracted oils related to evaporation was within range of 3.2–7.3% (w/w) at 27 °C. The SEM images of the black pepper confirmed different operation manners of mechanism between extractions using the solvents and heating process. The lowest MIC for both essential oils from conventional hidrodistillation and microwave-assisted hidrodistillation against two bacteria including E. coli and B. subtilis were found to be 137 µg mL⁻¹. The non-isothermal decomposition kinetics were investigated on the essential oil of microwave-assisted hydrodistillation extraction. The activation energies and pre-exponent factors of non-isothermal decomposition were found to be in range of 36.5–73.7 KJ mol⁻¹ and 4.98 × 10³–1.97 × 10⁸ s⁻¹, respectively, dependent on conversional fractions of the oil. The results revealed that chemical components, physicochemical properties and bioactivity of black pepper essential oils depended on the extraction techniques.     

用气相色谱仪测定变压器油中气体

本文采用多柱自动切换气相色谱仪和真空全脱气装置对变压器和互感器用油中的气体进行了系统的分析，除可测定油中的氢、甲烷、乙炔、乙烯、乙烷、二氧化碳和一氧化碳等气体外，还可根据不同需要测定氮、氧以及Ｃ３和Ｃ４烃的含量。本方法已用于诊断变压器和互感器内部变化及故障。