Thermal Degradation Process of Synthetic Lubricating Oils: Part I—Spectroscopic Study

The characterization of thermal degradation process of synthetic lubricating oils in relation to its spectroscopic properties was evaluated in this work. The fundamental key to understanding synthetic lubricating oxidation is having basic knowledge of the chemistry of lubricants and their degradation. Synthetic lubricants were degraded at different temperatures and times, under air atmosphere. After thermal degradation, lubricant oils were characterized by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR) and gas chromatographic/mass spectrometry (GC/MS). IR, NMR, and GC/MS spectra indicated oxidation reaction products.     

Determination of the Thermal Decomposition Products of Terephthalic Acid by Using Curie-Point Pyrolyzer

The thermal decomposition behavior of terephthalic acid (TA) was investigated by thermogravimetry/differential thermal analysis (TG/DTA) and Curie-point pyrolysis. TG/DTA analysis showed that TA is sublimed at 276°C prior to decomposition. Pyrolysis studies were carried out at various temperatures ranging from 160 to 764°C. Decomposition products were analyzed and their structures were determined by gas chromatography–mass spectrometry (GC-MS). A total of 11 degradation products were identified at 764°C, whereas no peak was observed below 445°C. Benzene, benzoic acid, and 1,1′-biphenyl were identified as the major decomposition products, and other degradation products such as toluene, benzophenone, diphenylmethane, styrene, benzaldehyde, phenol, 9H-fluorene, and 9-phenyl 9H-fluorene were also detected. A pyrolysis mechanism was proposed based on the findings.     

再生润滑油着色物质的研究

采用白土精制和溶剂精制工艺对再生润滑油J和B进行了脱色处理,并采用裂解 气相色谱 质谱联用(Py GC/MS)分析方法探究了白土吸附物和萃取物的化学结构。对脱色精制前后的油品进行了氧化安定性评价。结果表明,脱色处理降低了再生润滑油的色度号。J油脱出物中含有较多杂环氮化物或疑似抗氧剂烷基二苯胺氧化产物的含氮化合物,而B油脱出物中氮化物含量较少,但含有多种润滑油使用的添加剂。J油中的着色物质主要是天然氮化物和二烷基苯胺类抗氧剂的氧化产物;B油中的着色物质主要是烃类的氧化产物--酮、醛等衍生物。精制后油品抗氧性能相比于精制前下降比较明显。精制工艺脱出物的分析结果与精制后油品抗氧性能下降的实验现象有一定相关性。     

离子液体催化癸烯-苯烷基化合成高性能润滑油基础油

 采用Et₃NHCl-AlCl₃离子液体催化剂对苯与癸烯-1的烷基化反应和癸烯-1齐聚反应进行了研究。探讨了反应温度(25~75℃)和反应时间(1~4 h)对烷基化反应和齐聚反应的影响。采用气相色谱、质谱和红外光谱表征了产物的组成和结构,按照石油和石油产品试验方法国家标准测定了产物的黏度、倾点和相对分子质量。结果表明,在实验条件下,烷基化产物和齐聚产物均为理想的高黏度指数、低倾点的润滑油基础油组分,其中烷基化产物为癸烯四聚、五聚物以及二烷基苯的混合物,该产物的黏度指数(114~158)高、倾点(-48~-56℃)低、相对分子质量(425~515)适中;齐聚产物(PAO)的100℃黏度范围19.4~29.6 mm²/s、黏度指数范围138~164、倾点范围-48~-60℃、相对分子质量范围460~620。     

EFFECT OF ATTAPULGITE CLAY ON THE COMPOSITION OF JET FUELS

To identify the chemistry of polar molecules affecting the stability of jet fuels, spent Attapulgite clays collected from the top, middle and the bottom of the clay treater, were analyzed. The GC/MS analysis allowed for the selective desorption of polar organic molecules. At the low temperature range of 50–200°C, the GC/MS analysis showed desorption of C₉–C₁₆ hydrocarbons which are typical jet fuel molecules. At the higher temperature range of 50–400°C, the GC/MS analysis of spent clays showed desorption of water, amines, pyridines, quinolines, thiophenes, sulfides, thiols and alkylbenzenes. At the high temperature range of 50–600°C, the GC/MS analysis showed desorption of water, phenols, pyridines, quinolines, alkylbenzenes and other unidentified N compounds. No desorption of S compounds was observed above 400°C. Desorption of water above 200°C indicated that the water molecules were held inside the crystalline structure of the clay. The Attapulgite clay was found to be effective in adsorbing a wide range of polar molecules from jet fuel. Desorption of pyridines, quinolines and alkylbenzenes below and above 400°C indicated that their chemistry was different and required different energy to desorb from the clay. The high adsorbent capacity clays capable of adsorbing different chemistry polar molecules are required to assure stability of jet fuels.     

CHARACTERIZATION OF POLAR EXTRACTS FROM TWO PETROLEUM-DERIVED FUELS

Abstract

Petroleum fuels of marginal stability have been used as a source of nitrogen-rich polar extracts. Polar compounds were isolated by mild acid extraction followed by silica gel adsorption. The extracts were characterized and identified by combined capillary column GC/MS. Both fuels were studied by two methods under accelerated storage conditions, bottle tests and oxygen overpressure. Bottle tests were conducted at 80°C for 14 days and the oxygen overpressure at both 65 and 43°C for 6 days and 4 weeks respectively. Filterable insolubles and adherent gum were measured for both methods. Peroxide numbers were determined by ASTM D3703-85 for both stressed and original fuel samples.     

润滑油溶剂精制过程中有机酸的GC／MS研究

用毛细管气相色谱－质谱联用技术对润滑油溶剂精制中回收溶剂Ｎ－甲基吡咯烷酮（ＮＭＰ）中残留的有机酸进行了研究；对这些有机酸的甲酯化物色谱分离出２６个甲酯峰，由ＧＣ／ＭＳ确定了其中的１７个主要成份，约占有机酸甲酯总量的９０．８１％。色谱还分离出一个二重峰，占整个样品总量的８６．５３％，ＧＣ／ＭＳ确定其为４－甲氨基丁酸和ＮＭＰ，从而得到了循环溶剂ＮＭＰ中存在氧化水解产物的证据。     

Thermal Degradation of Asphaltene and Infrared Characterization of Its Degraded Fractions

Abstract

Petroleum asphaltene and its thermally degraded fractions are characterized using thermal analysis and infrared spectrometry, respectively. Thermal analysis of asphaltene has demonstrated that heating rate is important in studying thermal degradation of asphaltene. Asphaltene goes through three stages of mass reduction under thermogravimetric analysis from 25 to 1,000°C at a heating rate of 1°C/min and below. The products from thermal degradation of asphaltene at three different temperature intervals are collected. The collected fractions are characterized using a Fourier transform infrared spectrometer. The fraction collected between 220 and 350°C demonstrates similar infrared spectrum to that of asphaltene, however, with less aromatic properties. The fraction collected between 350 and 450°C resembles the undegraded asphaltene most based on the infrared spectra obtained. The fraction collected between 450 and 650°C demonstrates a spectrum that is totally different from those of the undegraded asphaltene and the other two fractions. In addition, a high degree of oxidation is observed on all of the three degraded fractions of asphaltene.     

Multiple reaction monitoring of GC/MS/MS analysis of terpanes and its application to petroleum exploration

A highly sensitive and accurate multiplex gas chromatography–mass spectrometry–mass spectrometry (GC/MS/MS) technique and GC/MS technique are tested for terpanes in a hydrocarbon source rock sample. The terpanes, including tricyclic, tetracyclic, and pentacyclic, were quantified monitoring and identified with the transition m/z (262+14n)→191, 330→191, and (370+14n)→191 by multiple reaction monitoring of GC/MS/MS technique using collision energies of 5–30 eV. Results show that collision energies have great influence on tricyclic and pentacyclic terpanes' ratios. After comparing the analysis results by GC/MS, the collision energy for detecting terpanes using the MRM-MS/MS method is optimized at 23 eV.     

MECHANISMS OF GASOLINE DEPOSIT FORMATION IN ENGINE INDUCTION SYSTEMS, CHARACTERIZATION OF PRODUCT REACTION BETWEEN BENZOTHIOPHENE OXIDES AND BASIC NITROGEN AND NAPHTHENIC COMPOUNDS

To evaluate the role of different types of gasolines compounds in the deposit formation process in engine admission systems, a series of reactions between toluene, octene and benzothiophenes derivates and benzothiophene oxides have been studied. To continue with the study of establishing the funtionalities more prone to react towards deposit formation, reactions between benzothiophene oxides with aniline mixture and cyclopentane were carried out under reflux conditions, using carbon tetrachloride as solvent. Samples of the reaction mixture were taken after 24 hr and identification was made by pyrolisis/gas chromatography/mass spectrometry (Py/GC/MS) and mass spectrometry/mass spectrometry (MS/MS). The aniline sample reaction showed the formation of new products at masses m/z 246, 260 and 274 daltons which were identified as diphenildisulfur derived compounds. The cyclopentane sample reaction showed a product at m/z 386 daltons, characterized by MS/MS as a new intermediate compound generated during the formation of naphthobenzothiophenes. No reaction product with anilines was detected. Possible structures of these products are proposed based on MS/MS mapping experiment.     

四种油溶性离子液体复合锂基润滑脂理化性能和摩擦学性能

合成4种不同结构的油溶性离子液体(N/P协同(a)、N/S协同(b)、P/P协同(c)、P/S协同(d))并按比例分别溶解在PAO10中作为基础油添加剂,制备4种新型油溶性离子液体润滑脂GA、GB、GC和GD.系统研究了油溶性离子液体分子结构差异,对所制润滑脂的热稳定性、滴点、锥入度以及摩擦学性能的影响.结果表明:以P...     

聚α-烯烃润滑油基础油热氧化安定性试验研究

采用润滑油薄层油膜微氧化试验与红外光谱分析联用技术,模拟合成航空润滑基础油聚α-烯烃在设定条件下的氧化后沉积物含量、油样质量损失与甲基吸收峰的红外光谱面积比(CSI)随氧化时间的变化关系。结果表明：油样经氧化90 min后即开始产生沉积物,随着氧化时间的延长,油样的质量损失和沉积物含量逐渐增加;氧化油样的CSI值先增大后减小,氧化程度逐渐加深,在230 ℃下良好的热氧化安定性可保持90 min左右。     

国产与进口聚α-烯烃润滑油性能对比

以国产低黏度聚α-烯烃润滑油为研究对象,通过黏度、酸值、倾点等指标,结合差示扫描量热(DSC)技术,考察其理化性能品质,并与同规格进口产品相比较,分析二者在润滑性、腐蚀性、热氧化安定性等方面的差异。结果表明:国产聚α-烯烃润滑油的酸值和倾点受温度影响较小,而黏度受温度的影响较大,随着反应温度的升高,运动黏度逐渐降低,且进口产品的变化幅度明显大于国产产品;国产与进口聚α-烯烃润滑油基础油的热氧化安定性相差不大,对抗氧剂的感受性也差别不大,在较高的温度下,胺型抗氧剂的抗氧化性能均优于酚型抗氧剂。     

Interfacial and Thermal Characterization of Asphaltenes Separated from Crude Oils Having Different Geological Origins

Abstract

Three crude oils having different geological origins, namely, DK from Eocene (Sylhet limestone and Langpar), SL from Barail (Oligocene), and JN from Tipam (lower Miocene), were selected. Asphaltenes were separated and characterized. Fourier transform infrared (FTIR) spectroscopy showed the presence of polar groups. Interfacial tension studies of the asphaltenes between benzene–water, toluene–water, and xylene–water showed the lowest interfacial tension with SL asphaltenes in a toluene–water system. Thermogravimetric analysis of asphaltenes indicates greater thermal degradation for DK asphaltenes. Asphaltenes were pyrolyzed and the pyrolyzed products were analyzed by gas chromatography/mass spectrometry (GC/MS). Based on the distribution pattern of n-alkanes in pyrolyzed product of asphaltenes, crude oils, and kerogens, it was concluded that crude oil and asphaltenes originate from the same source and asphaltenes are the unconverted parts of kerogens.     

Utility of Bacterial Biomass as Antioxidant,Anticorrosive, and Antifriction Additives for Lubricating Oils

Abstract

Bacterial biomass was used as antioxidant and anticorrosive additives for lubricating oils using three concentrations 0.1, 0.5, and 1%, respectively, the additive and corrosive products were determined for 36 hr of heating at 150°C. The Pseudomonas chlororaphis suspended in lubricating oil was heated at 150°C to form Maillard reaction products (MRP). These bacterial biomasses were also used as antioxidant and anticorrosive additives for different petroleum lubricants.     

PYROLYSIS OF SUNNYSIDE (UTAH) TAR SAND: CHARACTERIZATION OF VOLATILE COMPOUND EVOLUTION

ABSTRACT

Sunnyside (Utah) tar sand was subjected to programmed temperature pyrolysis and the volatile products were detected by tandem on-line mass spectrometry (MS/MS) in real time analyses. A heating rate of 4°C/min from room temperature to 900°C was employed.

Evolution of hydrogen, light hydrocarbons, nitrogen-, sulfur-, and oxygen-containing compounds was monitored by MS or MS/MS detection. Evolution of volatile organic compounds occurred in two regimes: 1) low temperature (maximum evolution at 150 to 175°C), corresponding to entrained organics, and 2) high temperature (maximum evolution at 440 to 460°C), corresponding to cracking of large organic components. Alkanes and alkenes of two carbons and higher had temperatures of maximum evolution at approximately 440°C, and methane at approximately 474°C. Aromatic hydrocarbons had temperatures of maximum evolution slightly higher, at approximately 450° C. Some nitrogen-, sulfur-, and oxygen-'ccntaining compounds were also detected in the volatile products.

Comparing the Sunnyside pyrolysis to the pyrolysis of other domestic tar sands indicated the following for hydrocarbon evolution: 1) the evolution of entrained organics relative to the total evolution was much less for Sunnyside tar sand, 2) the temperatures of maximum evolution of hydrocarbons due t o cracking reactions were slightly lower, and 3) the temperatures of maximum evolution for benzene and toluene are slightly higher than observed for other tar sands.

In general, the noncondensible gases, H₂, CO, and CO₂, exhibited evolution associated with hydrocarbon cracking reactions, and high temperature evolution associated with mineral decomposition, the water-gas shift reaction, and gasification reactions. Pyrolysis yields were dominated by the evolution of carbon oxides and water. The CO₂ primarily appeared t o cane from the decomposition of carbonate minerals. Compared t o other domestic tar sands, the gas evolution reflected more mineral decomposition character for Sunnyside tar sand.     

加氢裂化产品分子组成特点及其随转化深度的变化规律研究

采用气相色谱/质谱（GC/MS）及气相色谱/场电离-飞行时间质谱（GC/FI-TOF MS）对加氢裂化全馏分产品进行表征分析,考察了全馏分产品的分子组成特点,并对其分子组成随反应深度的变化规律进行探讨。结果表明：全馏分产品中正构烷烃主要分布在C18～C40的较高碳数范围内;随转化深度的增加,异构烷烃含量大幅度增加,正构烷烃含量整体变化较小,原料中链烷烃的含量及组成直接影响尾油馏分产品BMCI值及低温流动性;在全馏分产品的环烷烃化合物中,C5～C13范围内一环环烷烃含量最高,侧链碳数大于7的一至三环环烷烃更易发生断侧链反应,趋向于转化为侧链碳数更低的环烷烃化合物;芳烃化合物主要分布在小于350 ℃馏分中,主要以烷基苯、茚满及萘满的形式存在,较少以无侧链取代苯的形式存在。     

Changes in resistance of Salmonella Typhimurium biofilms formed under various conditions to industrial sanitizers

The aim of this study was to understand how different factors including biofilm age, attachment surface (stainless steel and acrylic) and various growth conditions such as different pH (pH 6 and 7) and temperature (28, 37 and 42 °C) affected the resistance of Salmonella Typhimurium biofilm against industrial sanitizers. The sanitizers tested were quaternary ammonium compounds (QAC, 200 ppm), mixed peroxyacetic acid/organic acids (PAO, 0.1%) and sodium hypochlorite (chlorine, 50 ppm). It was observed that, for biofilms formed at pH 7–37 °C, chlorine was the most effective sanitizer, followed by QAC and PAO. For all conditions tested, attachment surfaces didn't cause any significant difference in biofilm resistance against sanitizers. Increasing biofilm age led to an increase in resistance to sanitizers, although such effect was growth condition- and sanitizer-dependent. The resistance of biofilm formed on stainless steel at pH 6–37 °C increased with increasing biofilm ages. The effect of temperature and pH on biofilm resistance was dependent on biofilm ages. For 168-h biofilm formed at pH 6, the resistance to all three sanitizers was highest for 37 °C, followed by 28 and 42 °C; while biofilm formed at 37 °C for 168 h, pH 6 condition increased biofilm resistance to QAC and PAO, but not chlorine, compared with pH 7. These results indicate that the resistance of biofilms against sanitizers was dependent on biofilm age, temperature, and pH.     

Wild melon: a novel non-edible feedstock for bioenergy

In the present research work, a non-edible oil source Cucumis melo var. agrestis(wild melon) was systematically identified and studied for biodiesel production and its characterization. The extracted oil was 29.1% of total dry seed weight. The free fatty acid value of the oil was found to be 0.64%, and the single-step alkaline transesterification method was used for conversion of fatty acids into their respective methyl esters. The maximum conversion efficiency of fatty acids was obtained at 0.4 wt% Na OH(used as catalyst), 30%(methanol to oil, v/v) methanol amount, 60 ℃ reaction temperature,600-rpm agitation rate and 60-min reaction time. Under these optimal conditions, the conversion efficiency of fatty acid was 92%. However, in the case of KOH as catalyst, the highest conversion(85%) of fatty acids was obtained at 40%methanol to oil ratio, 1.28 wt% KOH, 60 ℃ reaction temperature, 600-rpm agitation rate and 45 min of reaction time.Qualitatively, biodiesel was characterized through Fourier transform infrared spectroscopy(FTIR) and gas chromatography and mass spectroscopy(GC–MS). FTIR results demonstrated a strong peak at 1742 cm~(-1), showing carbonyl groups(C=O)of methyl esters. However, GC–MS results showed the presence of twelve methyl esters comprised of lauric acid, myristic acid, palmitic acid, non-decanoic acid, hexadecanoic acid, octadecadienoic acid and octadecynoic acid. The fuel properties were found to fall within the range recommended by the international biodiesel standard, i.e., American Society of Testing Materials(ASTM): flash point of 91 ℃, density of 0.873 kg/L, viscosity of 5.35 c St, pour point of-13 ℃, cloud point of-10 ℃, total acid number of 0.242 mg KOH/g and sulfur content of 0.0043 wt%. The present work concluded the potential of wild melon seed oil as excellent non-edible source of bioenergy.     

Development of a liquid chromatography-tandem mass spectrometry method for simultaneous detection of the main milk allergens

The goal of this study is development and validation of a method to confirm and quantify milk allergens in food products based on liquid chromatography-tandem multiple reactions-monitoring, mass spectrometry (LC-MRM/MS). Here, emphasis was placed on two whey proteins, α-lactalbumin (α-La) and β-lactoglobulin (β-Lg), plus a third, α_s1-casein (α_s1-CN), known to be the main allergenic components of milk. Five marker peptides (one for α-La, two for β-Lg and two for α_s1-CN) and three quantitative marker peptides from the digestion of standard milk proteins were identified using matrix-assisted laser desorption/ionization with tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS). Optimization of enzymatic hydrolysis conditions were defined as 37 °C for 16 h. The linearity ranges for the three allergenic proteins (α-La, β-Lg and α_s1-CN) were 0.97–31.25 μg/mL, 0.48–31.25 μg/mL and 0.48–31.25 μg/mL, respectively. The assays were validated for absolute quantification of three milk proteins with satisfactory results, which indicates that the established mass method is suitable for the expression of levels in daily food.