Synthesis of butyl-octyl-diphenylamine as lubricant antioxidant additive by ionic liquids

Ionic liquid used in Friedel-Crafts reaction catalytic of dialkyl diphenylamine is a green environmental method. In this paper, butyl-octyl-diphenylamine (BODPA) was synthesized by the series of 1-butyl-3-methylimidazolium chloroaluminate (BMIM-AlCl₃) ionic liquids catalysts. Pressure differential scanning calorimetry (PDSC) was used to test antioxidant properties of BODPA in lubricating oil. The influences of various reaction parameters such as dosage of catalysts, molar ratio of diphenylamine to chloralkane, reaction temperature, and time on the alkylation catalyzed by BMIM-AlCl₃ have been studied. The molecular structure and content of alkyl diphenylamine were also characterized by FT-IR/GC-MS.     

润滑油氧化安定性评价方法及与PDSC的相关性研究

润滑油氧化安定性是决定润滑油使用寿命的主要指标之一。氧化安定性的评价方法多种多样,大致可分为氧化管试验法、旋转氧弹法和PDSC法三大类。氧化管试验法和旋转氧弹法是两类经受了长期的实践检验的模拟试验方法。PDSC是一种热分析方法,在润滑油氧化安定性研究中用途日益广泛,本文评述了其与氧化管试验法和旋转氧弹试验法之间的比较研究现状。     

Alkylated naphthalenes as high‐performance synthetic fluids

The physical and chemical properties for a series of structurally well‐defined, alkylated naphthalenes have been compared. Structural characteristics, such as the alkyl chain length, alkyl chain branching, and number of alkyl groups on the naphthalene ring, have been correlated with physical properties, such as viscosity, viscosity index, pour point, and aniline point. The thermo‐oxidative stability of the alkylated naphthalenes was evaluated by the rotating pressure vessel oxidation test (RPVOT), a bulk oxidation test (BOT), and pressure differential scanning calorimetry (PDSC). Although all of the alkylated naphthalenes showed better thermo‐oxidative stability than other traditional hydrocarbon‐based fluids, the relative performance of the structurally different alkylated naphthalenes was found to be test dependent. Initial RPVOT studies with a linear polyalkylated naphthalene show that it gives good additive response to the incorporation of traditional antioxidants.     

The relationship between oxidation stability and antioxidant depletion in turbine oils formulated with Groups II,III and IV base stocks

Using simple turbine oil formulations, we studied the effects of different antioxidant systems on oxidation behaviour. Fourier transform infrared was used as a sensitive probe to monitor the depletion of different antioxidant types present in turbine oils based on Group II, III and IV base stocks. It was found that the depletion of alkylated diphenylamine antioxidants from turbine oil systems is generally slower when hindered phenolics are present in the formulation. Furthermore, the type of hindered phenolic used in the formulation is critical for preserving this amine activity, with the bis‐phenolic 4,4‐methylenebis(2,6‐di‐tert‐butylphenol) showing superior performance over a phenolic ester of approximately the same molecular weight. This effect was explained by the higher hindered phenolic activity of the bis‐phenolic relative to the phenolic ester. The ability of the bis‐phenolic to preserve or protect the amine antioxidant, combined with its higher hindered phenolic activity, was shown to improve the oxidation resistance of turbine oils. The results also showed a surprisingly high oxidation stability for turbine oils formulated with Group III base stock, with the oxidation resistance of the Group III systems exceeding that of the equivalent Group II and Group IV systems. Copyright © 2007 John Wiley & Sons, Ltd.     

Thermo‐oxidative stability of high‐temperature stability polyol ester jet engine oils — a comparison of test methods

Thermo‐oxidative stability in aerospace turbine oils is an important criterion. A new category (HTS) of turbine oil has been introduced, and the present work compares data on the oxidation stability of HTS oils obtained using the FTM 791, method 5308 test, at various temperatures, and PDSC experimental data, to standard class oils (STD). PDSC has become established in recent years as an effective means with which to establish the thermo‐oxidative stability of oils. The purpose of the present work was to find out whether PDSC could identify HTS oils correctly, and also to increase our understanding of some of the chemical processes behind the test results. Analogies in the degradation of the oligomer antioxidants have been confirmed by MALDITOF mass spectra.     

A comparative study of phenol‐type antioxidants in methyl oleate with quantum calculations and experiments

Chemical software (Gaussian 98w) was used to calculate the highest occupied molecular orbital (HOMO) energy level of three phenol‐type antioxidants to evaluate their oxidation resistance performance. The conclusion drawn from the quantum calculations was that the decreasing order of the oxidation resistance effectiveness was 4,4‐methylene‐di(2,6‐di‐t‐butyl‐phenol) (T511)>2,6‐di‐t‐butyl‐4‐methylphenol (BHT)>phenol. Pressure differential scanning calorimetry (PDSC) and the rotary bomb oxidation test were also used to assess the antioxidants in a methyl oleate base oil. According to the experimental results, the oxidation resistance capability of the three antioxidants decreased in the order BHT > T511 > phenol. The results indicated that the quantum calculation method could be used to screen antioxidants with regard to their oxidation resistance effectiveness.     

Characterization of Model Perfluoropolyalkylethers by Miniaturized Thermal Oxidative Techniques–-Part II: Pressure Differential Scanning Calorimetry

Commercially available and model perfluoropolyalkylether (PFPAE) fluids were characterized by pressure differential scanning calorimetry (PDSC). Details of the PDSC method are described and the stabilities determined by PDSC are compared to those obtained from the constant temperature miniaturized oxidation corrosion test described in Part I of this paper (1). Chemical structure-thermal oxidative stability relationships of the fluids as derived from the PDSC method are discussed. The destabilizing effect of an -OCF2-group is confirmed and other more subtle effects are noted.     

利用PDSC考察环境友好润滑油基础油氧化安定性的研究

结合环境友好润滑油产品的开发工作,用加压差热扫描示量法(PDSC)研究了菜籽油、双酯、多元醇酯等几种基础油的氧化稳定性,并与旋转氧弹的结果进行了比较;对菜籽油在不同温度下的氧化反应特性进行了考察,并采用阿仑尼乌斯公式计算了菜籽油氧化反应的活化能,初步研究了其氧化反应机制。试验结果表明,PDSC可用于评价基础油的氧化安定性,合成酯的氧化安定性明显优于菜籽油,且多元醇酯的氧化安定性最好。     

Utilising Fenton reagent to simulate oxidation processes in turbine oil

To meet the demands of less‐sludge deposit and longer‐service life, turbine oils need to possess superior oxidation stability. Commercially available turbine oil nitrogen tetroxide (NTO) became green in an actual turbine, which was a risk of serious damage to turbine bearing and lubricating systems. By analysis of pH discoloration, infrared spectroscopy, it is found that the chromogenic materials in in‐service oil of NTO (UTO) were the oxidation products of diphenylamine antioxidant at low temperatures. Then, a method utilising Fenton reagent was developed to accelerate oxidation process for assessment of discoloration of turbine oil in service. By screening of experimental conditions, the colour and structure of chromogenic materials in accelerated oxidation products from NTO are the same as those of in‐service oil of NTO. Turbine oils in different formulation are oxidised by Fenton reagent in preceding condition. The colours of oxidation products are consistent with the results of ASTM D943 after 1000 h test. This study also provided a better understanding of the oxidation process affecting lubricants and the functional mode of the radical scavenger antioxidant. Copyright © 2013 John Wiley & Sons, Ltd.     

工业齿轮油长周期密封相容性研究

工业齿轮油与齿轮箱密封圈的相容性对于机械设备正常运转至关重要.近些年随着齿轮箱技术不断发展,工业齿轮油密封相容性要求越来越严苛,高端齿轮箱采用常规静态相容性测试已不能满足要求,需采用长周期静态试验,以及与齿轮箱实际工况最为契合的长周期动态密封试验来评价工业齿轮油密封相容性.对3种不同抗氧剂体系的L-CKD矿物型工业齿轮...     

模拟工况条件下改性烃类航空润滑油综合性能对比分析

为了满足航空发动机日益严苛的工况要求,通过向某烃类航空润滑油中添加不同量的添加剂,制备一系列改性航空润滑油;采用氧化工况模拟标准装置,分别测试不同氧化时间、不同氧化温度下,改性油样及原油样的黏度、酸值、倾点、抗磨性能、承载能力、起始氧化温度(IOT)、氧化诱导期(OIT)等性能指标,评价改性油样的综合性能。实验结果表明：氧化温度越高,改性油样颜色加深速度越缓慢,即抑制油品氧化效果越明显;相同氧化条件下,改性油样与原油样相比,酸值增速较低,即改性后油样能有效抑制酸值升高,改善了油品的抗腐蚀性能,同时改性对油品的黏度、倾点未产生不良影响;油样改性后未对抗磨性能产生不良影响,但有可能导致油品的承载能力下降,不过影响在可控范围内;油样改性后IOT、OIT值提升,氧化安定性明显改善。     

不同氧化条件下柴油机油的氧化降解研究

为探讨氧化温度、时间以及金属催化氧化等因素对柴油机油性能的影响,采用高温烘箱以及氧化测试仪模拟不用的氧化条件,研究柴油机油氧化前后部分理化性能、摩擦学性能的变化,分析不同氧化条件对柴油机油的氧化过程及性能的影响规律.结果表明:高温烘箱试验后发动机油的理化性能、抗氧化性能以及摩擦学性能会有一定程度的劣化,但变化幅度不大,...     

氯乙基甲醚氨基甲酸酯的合成及性能研究

介绍了一种新型润滑油添加剂氯乙基甲醚的氨基甲酸酯的制备过程及其各项性能,采用旋转氧弹、PDSC和四球摩擦磨损试验机考察了其在矿物基础油中的抗氧化性能和抗磨性能,以及与几种抗氧化和抗磨损添加剂间的协同性能。结果表明:这种新型的润滑油添加剂具有一定的抗氧化性能和良好抗磨损性能,与胺型抗氧剂、ZDDP复合使用,具有增效协同作用。     

High temperature oxidation stability of automotive crankcase oils and their base oils

A modified open test tube type of apparatus has been used to assess the high-temperature oxidation stabilities of two grades of automotive crankcase oils and their base oils under conditions that simulate those encountered in the internal combustion engines. The method involved keeping the oil temperature at 180°C with an air flow of 1.0 L/min for 65 hours and evaluating the soluble oil acidity, pentane insolubles, volatile acidity and total oxidation products formed. The procedure detected that the oil acidity increased exponentially and sludge formation started after a threshold level of oxidation products had been formed. Volatility losses were found to be appreciable, and the antioxidant additives were quickly used up under the simulated conditions. Therefore only a mineral oil of high natural antioxidant capability could provide improved performance at high temperatures. The total oxidation product proved to be a valuable source of information on the extent of oil oxidation and oxidation stability study.     

一种耐轴承腐蚀和磨损的复合锂基润滑脂的研制

研究不同类型极压抗磨剂、抗氧剂和防锈剂等对复合锂基润滑脂性能的影响,并复配一种多功能复合添加剂制备出复合锂基润滑脂。所研制复合锂基润滑脂的梯姆肯值为266 N、高温下氧化诱导期为761 min、滴点大于330℃,且通过了FE 8轴承磨损和EMCOR轴承腐蚀台架的检测。研究结果表明:所研制的复合锂基脂具有优异的极压抗磨、高温抗氧及耐轴承腐蚀和磨损等性能,应用效果良好。     

脂肪酶Novozym435改性大豆油的摩擦学性能研究

为提高食用大豆油作为润滑剂的抗磨性能,在超声振动条件下采用脂肪酶Novozym435作为催化剂使食用大豆油中的不饱和脂肪酸与甲醇进行环氧化反应,在温和反应环境下合成一种改性大豆油.利用红外、拉曼光谱仪对其结构进行表征,使用同步热分析仪TG-DSC考察其热氧化稳定性,在四球机上考察其摩擦磨损性能,用扫描电子显微镜、三维表...     

Oxidation stability of gasoline engine lubricants: Effect of base-oil chemistry in laboratory and engine tests

This paper presents a laboratory test called the Iron Catalysed Oxidation Test (ICOT), where air is bubbled through an oil sample at 165 °C. This test, shorter than the CEC L-48 test, provides an easy method of gasoline engine lubricant screening. A basic study has shown that this kind of test is suitable for the discrimination of base-oil properties and that the oil viscosity increase at the end of the test is highly indicative of the oxidation processes at work. In this study, the base-oil assessment is carried out with an API SG SAE 15W-40 oil, and the results depend directly on the aromaticity of the base oil. Several engine test sequences, including CEC L-55-T-95: TU3M HT, were also applied to these formulations, which differ only in their base oils. The results of those sequences where oil consumption was low roughly correlated with the laboratory test results. However, when there was a high loss of volatile matter in the engine tests, the oil viscosity increase was greatly modified, and this parameter can override the effect of oxidation.     

Influence of oil temperature on gear failures

Typical gear failures like wear, scuffing, micropitting and pitting are influenced by the oil temperature in the lubrication system. High temperatures lead to low viscosities and thus thin lubricant films in the gear mesh with generally detrimental influence on failure performance. On the other hand, for gear oils with additives higher temperatures correspond with higher chemical activity and, at least in some cases, with better failure performance of the lubricant. Last, but not least, at very high temperatures even metallurgical changes have been found with a reduction in material endurance limits. Examples for the influence of oil temperature on gear failure modes, as well as their introduction into load carrying capacity calculation methods are shown. With this background, the often-applied practice of increasing the severity of a gear oil test method by increasing the oil temperature has to be revised. Adequate solutions are discussed.     

Substituent Effect on the Reactivity of Alkylated Triphenyl Phosphorothionates in Oil Solution in the Presence of Iron Particles

The effect of the substituent attached to the phenyl rings on the reactivity of alkylated triphenyl phosphorothionates (t-butyl TPPT (b-TPPT) and p-nonyl TPPT (n-TPPT)) in oil solution at high temperature (423 and 473 K) was investigated by means of Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The FT-IR and NMR results show that the alkylated TPPTs were highly thermally stable and did not completely decompose in oil, even upon heating at 423 K for 168 h and at 473 K for 72 h, with and without steel filings and iron particles (both metallic iron and iron oxide particles). The reaction of alkylated TPPTs was found to start with the scission of the P=S bond to yield alkylated triphenyl phosphate. The kinetics of the thermo-oxidative reaction was slower when steel filings and iron particles were added to the oil solutions during the heating experiments. The reactivity of the unsubstituted molecule (TPPT) was higher than that of alkylated TPPTs at 423 K, while at 473 K TPPT and n-TPPT were more reactive than b-TPPT. In the case of the experiments performed at 473 K in the presence of steel filings or metallic iron or iron oxide particles, the reactivity of the alkylated TPPT molecules decreased with the length of the alkyl chain bound to the phenyl rings. The XPS results show that a reaction layer consisting of carbon, oxygen, phosphorus and iron was formed on the 100Cr6 steel filings immersed for 72 h in oil solutions containing alkylated TPPTs and heated at 473 K. Sulphur was neither detected on the surface nor in the composition vs depth profile. During the heating experiments, the base oil (PAO) was oxidized. At 423 K, the alkylated TPPTs had a strong antioxidant effect, which was found to be more pronounced upon increasing the length of the alkyl chain bound to the phenyl rings. At 473 K, the TPPTs did not inhibit the oxidation of the base oil as effectively as at 423 K.     

Synergistic and antagonistic effects on oxidation stability of antioxidants in a synthetic ester based oil

Synergistic and antagonistic effects have been observed with the four sulfur-, phosphorus- and heavy metal-free antioxidants, hindered bis-phenol, octylated diphenylamine, octylated phenyl-alpha-naphthylamine and tolutriazole derivative, on the oxidation stability, thermal and physicochemical properties of dioctyl sebacate oil. The oxidation stability was evaluated using a rotary bomb oxidation tester. The results from isothermal and catalytic RBOT oxidation tests suggested that ODPA has an antagonistic effect on the OIT. The combination of HP:OPANA:TZ exhibited the highest and most synergistic antioxidant activity. Furthermore, synergism was observed in terms of both oxidation and thermal stabilities through thermogravimetric analysis (TGA).