环戊胺基二硫代甲酸衍生物合成、表征及作为润滑油添加剂的摩擦性能

采用环戊胺基二硫代甲酸钠与不同烷基的氯乙酸酯进行取代反应,合成了一系列5个未见文献报道的环戊胺基二硫代甲酸基乙酸酯新型高效润滑油添加剂。产物用红外光谱、紫外光谱、核磁共振氢谱、核磁共振碳谱、质谱和元素分析测试技术对它们的结构进行了表征,结果表明,其结构与设计的结构吻合。所合成的添加剂油溶性好,能够溶于液体石蜡、乙酸乙酯和菜籽油等有机溶剂中,而难溶于水,本文选用的基础油为液体石蜡。采用热失重分析(TGA)对其热稳定性进行了评价,升温速度为10℃/min,N2气保护,其初始分解温度均高于195℃,最终分解温度达400℃,可满足润滑油添加剂的一般工况使用要求。在四球摩擦磨损试验机上考察了其在液体石蜡中的极压承载负荷(PB值),结果表明,这一类添加剂可以大幅度地提高液体石蜡的承载力,其中效果最好的PB值可达866N,与二烷基二硫代磷酸锌(ZDDP)的承载力(PB值为882N)几乎相当。添加剂分子中烷基链的长短和形状(不论是直链、支链还是环状)对PB值几乎没有影响。     

1,3,4-噻二唑-2-硫酮衍生物在菜籽油中的摩擦学性能研究

合成了2-十二烷硫基-4-苯基-1,3,4-噻二唑-5-硫酮(DBTT),用1H NMR,元素分析,红外光谱技术对其结构进行了表征,用热重分析仪考察了其热稳定性.作为菜籽油(RSO)添加剂,在四球摩擦磨损试验机上测试了其摩擦磨损性能;用扫描电子显微镜观察分析了钢球磨损表面形貌.结果表明:所合成的化合物具有较高的热稳定性,能够提高菜籽油的抗磨减摩性能.     

全氟聚醚润滑油添加剂抗氧抗腐蚀机理研究及分子设计——Ⅱ. N-取代聚全氟甲乙醚苯酰胺的合成和测试

依据前期研究全氟聚醚润滑油抗氧抗腐添加剂的结构特征,选择并合成了3个N-取代聚全氟甲乙醚苯酰胺抗氧抗腐添加剂.经光谱分析发现,合成的3个产物中苯环的紫外特征吸收峰分别在240.7,215.4和230.1nm附近;C==O的红外特征吸收峰分别在1713.9, 1712.2和1710.8cm^-1附近.测试合成的3个添加剂抗氧抗腐性能发现:加入合成的添加剂后,能将氟醚润滑油失重较空白样分别减少1/7,1/9,1/25倍,可将Al₂O₃ 催化下的热分解温度提高19～22℃.理论和实验研究表明:含氮杂原子的聚全氟甲乙醚苯酰胺化合物,既能接受R_fO的电子,生成稳定的加合物,阻止R_fO反应;又能给出电子与金属发生化学吸附,形成保护膜,具有较好的抗氧抗腐蚀性能;在这类化合物的N原子上引入供电子基团或苯基,可增加添加剂的抗氧抗腐蚀性能.研究结果可为设计新的抗氧抗腐添加剂提供有用的信息.     

两种无灰型含磷/硫润滑添加剂在菜籽油中的摩擦学性能及膜分析

以合成的两种无灰型含磷/硫化合物为润滑添加剂, 以可生物降解的菜籽油作为基础油, 用四球机研究了体系的抗磨减摩性能, 以X射线光电子能谱(XPS)和X射线吸收精细结构光谱(XANES)对所形成的摩擦膜和热膜进行了表面分析, 并初步探讨了其润滑机理. 摩擦学研究结果表明, 两种含磷/硫化合物作为菜籽油的润滑添加剂时, 具有良好的抗磨减摩性能. XPS和XANES分析结果显示, 摩擦膜和热膜主要由吸附层和反应层组成; 在表面膜中, 磷主要以磷酸盐或焦磷酸盐等形式存在, 而硫主要以硫酸盐的形式存在. 研究结果还表明, 摩擦热在两种不同添加剂的摩擦膜形成过程中发挥着不同的作用.     

一种高硫的噻二唑衍生物的摩擦学性能研究

合成了一种高硫含羟基和黄原酸的噻二唑衍生物(ESP),利用四球摩擦磨损试验机考察了其在Corda3970基础油中的摩擦磨损性能,表明所合成的添加剂能够有效的提高Corda 3970基础油的极压和抗磨性能,并且在一定的浓度范围内随着浓度的增加,其抗磨减摩性能增加。通过扫描电镜(SEM)分析了钢球表面形貌及元素分布,发现其主导作用的是边界膜中存在S、O、N活性元素,它们形成复合膜是添加剂具有摩擦学性能的主要原因。     

边界润滑条件下石墨与烷基硫代磷酸锌的协同作用

油溶性添加剂与团体润滑剂的相互作用是影响分散在润滑油中固体润滑剂作用的重要因素。本工作在SRV(微振动摩擦磨损)试验机和Falex试验机上考察了边界润滑条件下液体石蜡中石墨与极压抗磨添加剂二烷基二硫代磷酸锌(ZDDP)在摩擦、磨损及承载能力方面的相互影响,并在相同的条件下比较了石墨分别与极压抗磨添加剂磷酸三甲酚基酯(TCP)和二苄基二硫(DBDS)的相互影响。     

烷基咪唑啉硼酸酯与常用切削液添加剂的配伍性能研究

在四球试验机和攻丝扭矩模拟评定试验机上考察了新型多功能金属加工液添加剂烷基咪唑啉硼酸酯(MB 1 )与常用金属加工液添加剂复配后的承载、极压和攻丝扭矩试验性能。所选择的常用金属加工液添加剂有 :油性剂 :油酸 ;极压剂 :二硫代氨基甲酸钠。结果表明 ,烷基咪唑啉硼酸酯与上述两种添加剂存在程度不同的复配作用。     

硫化菜籽油的催化合成及其摩擦学特性

以精制菜籽油为原料,天然丝光沸石为催化剂,研究了硫化菜籽油的催化合成,并借助FTIR测试技术分析了产物的化学结构. 通过四球摩擦磨损试验机考察了其摩擦学性能,同时对磨痕表面进行了XPS及显微分析,探讨了其润滑机理. 结果表明,随硫粉投料量的增大,菜籽油不饱和度逐渐降低,在丝光沸石催化下,硫化反应收率可达98%以上;含硫量从0增大到9.96%,硫化菜籽油的摩擦学性能明显提升,摩擦系数由0.085降为0.025,磨斑直径由0.56 mm降至0.42 mm,最大无卡咬负荷(PB值)由549 N升至745 N,烧结负荷(PD值)由1 960 N升至2 254 N;其润滑机理初步归结于硫化菜籽油在摩擦副表面上形成的吸附油膜,以及摩擦过程中由于摩擦化学反应形成的摩擦转移膜共同起减摩耐磨和极压作用.     

正丁基硫代磷酸酯的合成及其摩擦学性能研究

用MS、 FT-IR等方法对合成的三正丁基一硫代及四硫代磷酸酯进行了结构表征,并在四球摩擦磨损试验机上考察了其在液体石蜡中的摩擦学性能;用扫描电镜(SEM)和X射线光电子能谱(XPS)对钢球磨痕表面做了分析.结果表明: 对于钢-钢摩擦副,合成的两种硫代磷酸酯可以显著提高液体石蜡的极压抗磨性能,但不能改善其减摩性能.钢球磨损表面XPS和SEM分析结果表明,添加剂分子在金属表面发生物理或化学吸附,并导致金属表面的腐蚀和摩擦化学反应.     

淖毛湖煤加氢液化过程杂原子迁移转化研究

以淖毛湖煤为原料,进行加氢直接液化,考察了加氢温度与转化率和油收率的关系,并解析了加氢条件下煤中硫、氮和氧的迁移转化特性。结果表明,淖毛湖煤具有良好的液化性能,400℃和2 MPa氢初压条件下即可达到69.6%的转化率和55.3%的油产率。结合气相色谱质谱联用(GC-MS)和气相色谱-原子发射光谱(GC-AED)等方法对产物分析发现,以弱键合结构存在的硫、氮和氧等杂原子易发生加氢裂解生成H2S、NH3、H2O等。液化油品中含硫化合物主要以噻吩及噻吩同系物为主;含氮化合物含量极低,主要由含氮杂环化合物构成;含氧化合物在液化油中主要以酚及酚的同系物为主。存在于芳香结构中的杂原子会随着自由基缩合反应,生成更稳定的含杂原子稠环化合物富集在液化残渣中。     

Comparative study of the oxidative and thermal stability of vegetable oils to be used as lubricant bases

Demand for lubricating oils is increasing in the growing Brazilian economy. The use of vegetable bases in exchange of minerals can bring socio-economic and environmental benefits for Brazil. The purpose of this study is to compare the thermal and oxidative stability of vegetable oils related to the bases commonly used as lubricants. In this study, thermogravimetric analysis of castor oil, cotton oil, macauba’s almond oil, passion oil, paraffinic mineral oil, naphthenic oil (NH-140) and synthetic oil (Etro) was performed in inert and oxidative atmosphere to study the thermal and oxidative degradation of the vegetable oils related to the most common lubricants’ oils base. These oils’ oxidation stability were determined by standard procedures (ISO 6886). The use of mineral oil’s additives in these vegetable oils was tested to verify the viability of these additives to improve the oxidative stability of the vegetable oils. The castor oil and the cotton oil presented results of thermal analysis similar to the mineral and synthetic bases values. The castor oil was the only vegetable oil that showed a great oxidative stability. All other vegetable oils had their oxidative stability significantly increased by the additives.     

Oil‐Soluble Polymer Brush Grafted Nanoparticles as Effective Lubricant Additives for Friction and Wear Reduction

The development of high performance lubricants has been driven by increasingly growing industrial demands and environmental concerns. Herein, we demonstrate oil‐soluble polymer brush‐grafted inorganic nanoparticles (hairy NPs) as highly effective lubricant additives for friction and wear reduction. A series of oil‐miscible poly(lauryl methacrylate) brush‐grafted silica and titania NPs were synthesized by surface‐initiated atom transfer radical polymerization. These hairy NPs showed exceptional stability in poly(alphaolefin) (PAO) base oil; no change in transparency was observed after being kept at ?20, 22, and 100 °C for ≥55 days. High‐contact stress ball‐on‐flat reciprocating sliding tribological tests at 100 °C showed that addition of 1 wt % of hairy NPs into PAO led to significant reductions in coefficient of friction (up to ≈40 %) and wear volume (up to ≈90 %). The excellent lubricating properties of hairy NPs were further elucidated by the characterization of the tribofilm formed on the flat. These hairy NPs represent a new type of lubricating oil additives with high efficiency in friction and wear reduction.     

Environmentally friendly lubricating oil candidate

Synthetic lubricating oils based on renewable sources, excluding petroleum, have a great importance among all of the lubricating oil alternatives that are included in the research field about clean and environmentally friendly lubricating oil technologies. One of the environmentally friendly lubricating oils is a vegetable oil-based product. In this study, the esterification product of oleic acid with a fraction of molasses fusel oil as a lubricating oil candidate was determined according to the American Society for Testing and Materials (ASTM) standard tests. The results indicate that the ester product can be used as an environmental friendly lubricating oil or lubricating oil additive.     

Evaluation of the thermal stabilities of some aromatic hydroxy- and amine-type antioxidants

This paper discusses the evaluation of the thermal stabilities of some additives usually incorporated as antioxidants in mineral oils and lubricating greases. They include aromatic hydroxy and amine type organic compounds. The results of this thermoanalytical investigation, which was performed in a differential scanning calorimeter under ambient atmosphere and thermogravimetrically under an inert atmosphere of nitrogen gas, showed that the hydroxy-derived compounds, which are based on the quinolinic skeleton, to be of the highest thermal stability compared to those of the other additives studied.     

Modelling relation between oxidation resistance and tribological properties of non-toxic lubricants with the use of artificial neural networks

The lubricants based on vegetable oils, as environmental friendly, are urgently sought. However, in addition to ecological characteristics, the lubricating properties have to be met. To meet these requirements the active additives influencing the lubricating properties and oxidation resistance are used. The useful lifetime of lubricants is determined largely by their abilities to resist oxidation. The article presented the results of new, ecological lubricants development. The oxidation performances of different developed lubricants have been tested. The experimentally determined oxidation stability of the compositions based on vegetable oils are presented. Analysed oxidation onset temperature was obtained from the differential scanning calorimetry (DSC) curves, which provides the rapid prediction of the oxidative stability of lubricants. Besides the lubricating composition based on vegetable oils, the developed greases-based mineral, or synthetic oil were investigated. The properties of these greases were evaluated using the measurement of parameters describing structure (penetration) and resistance to high temperature (dropping point). The lubricating properties of both the greases and vegetable oil compositions were tested on four-ball testing machine. In the results of the modelling of the lubricating properties the neural network models for the both types of the lubricants were developed. A discussion of the research results and analysis of models validity is given below. The experimental results are compared with the calculated using the neural models. An acceptable agreement was achieved.     

Synthesis and tribological investigation of 4-vinyl guaiacol–based thioether derivatives as multifunctional additives and their interactions with the tribo surface using quantum chemical calculations

Novel 4-vinyl guaiacol based thioether derivatives were synthesized in a three-step reaction procedure by thiol-ene coupling as the key step. The synthesized compounds were characterised by spectroscopic techniques and evaluated for their tribological and antioxidant properties in two different base oils namely epoxy2-ethylhexyl esters of karanja fatty acids (EKE) and dioctyl sebacate (DOS). It was found that the synthesized products were exhibited superior antioxidant performance compared to butylated hydroxytoluene (BHT). All the three synthesized additives were improved the tribological properties of the base oil EKE and DOS. Dithio derivative at 0.75 wt% reduced the wear scar diameter by 36% and at 1 wt% improved the weld point by 33% of base oil EKE. Surface and elemental analysis result suggests that in the tribochemical process the synthesized thioether derivatives decompose and form an effective tribofilms on interacting surfaces. X-ray Photoelectron Spectroscopy (XPS) of the surface lubricated with base oil containing DMFD was evidence for the formation of tribofilm with FeS, FeSO₄ and Fe₂O₃. The antiwear behaviour of the additives was well correlated with quantum chemical calculations. Overall the dithio derivative is more effective as antiwear, extreme pressure and antioxidant bio lubricant additive than other thioether derivatives.     

Synthesis and antimicrobial activity of aminomethoxy-substituted 1-(ethylthio)heptanes

The Mannich condensation of 1-(ethylthio)heptane-2-ol, formaldehyde and secondary amines taken in equimolar amounts gives rise to new aminomethoxy-substituted 1-(ethylthio)heptanes in a yield of 70–77%. The structure of the synthesized compounds was proved by the elemental analysis, IR and ¹H NMR spectroscopy, and mass spectrometry. The compounds were tested as antimicrobial additives to lubricating oils. They were found to suppress effectively the activity of microorganisms.     

Synthesis of 1-propylsulfanylhexane aminomethoxy derivatives

Synthesis was performed of new aminomethoxy derivatives of 1-propylsulfanyl hexane by Mannich condensation of 1-propanethiol, secondary amines, and formaldehyde. The structure of compounds synthesized was established by elemental analysis, mass spectrometry, IR and ¹H NMR spectroscopy. Some compounds obtained were tested as antimicrobial additives to lubricating oils, and also as antiseptics against bacteria and fungi. It was established that these compounds are more efficient antimicrobial substances than the preparations currently used.