An X-ray photoelectron spectroscopy study of the effect of sulfur compounds on antiwear properties of diesel fuels

The chemical composition of tribolayers formed during steel-on-steel friction in the presence of diesel fuel and cetane (as a model hydrocarbon) containing organic sulfur compounds of different classes was studied by means of X-ray photoelectron spectroscopy. It was shown that difference in the antiwear properties between the test samples is due to the morphology of the formed tribolayers.     

Comparison of antiwear properties of titanium-containing compounds

In search for environmentally friendly lubricant additives, titanium 2-ethylhexanoate and titanium oleate, which titanium compounds soluble in white oil, have been synthesized, as well as titanium dioxide nanoparticles modified with tetra-(2-ethylhexyl)thiuram disulfide and di(2-ethylhexyl)thiophosphonodisulfide. These titanium compounds have been characterized by elemental analysis, thermogravimetry, and IR spectroscopy. By means of the small-angle X-ray scattering technique, it has been found that the TiO₂ nanoparticles have a size of 1?C10 nm. Evaluation of antiwear properties of titanium compounds on a ChS-hMT-1 tribometer in a white oil solution shows that the decrease in wear scar diameter is 38?C49% compared with the white oil. Analysis of the friction surfaces by atomic-force microscopy and X-ray microanalysis has shown a decrease in roughness of the friction surface caused by the presence of titanium atoms in the surface layers.     

Structural criterion for the antiwear properties of lube oils

A new concept was developed for evaluating the antiwear properties of lubricants-based on the value and distribution of the micromechanical characteristics in the near-surface layer deformed by friction. A diagnostic parameter for wear-fatigue processes is proposed: the micromechanical strength characteristic gradient, expressed in terms of the structural state criterion, formed in the near-surface layer of steel parts as a result of friction. This criterion can be used for assessing the antiwear and antiscuff properties of lube oils. Oils with high antiwear characteristics form minimal positive micromechanical property gradients in the near-surface layer of the metal. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 28–32, May–June, 2007.     

吸附脱除催化裂化柴油中硫化物

以硝酸活化后的活性炭负载CuO为脱硫剂,在固定床反应器中,对催化裂化柴油进行吸附脱硫.采用正交设计法,考察了硝酸质量分数、活化温度、焙烧温度、CuO负载量(CuO占活性炭的质量,下同)、床层温度等因素对脱硫性能的影响.结果表明,各因素对脱硫性能影响依下列顺序递减:硝酸质量分数,焙烧温度,活化温度,CuO负载量,床层温度.硝酸活化的最佳工艺条件为:硝酸质量分数65%,焙烧温度450℃,活化温度80℃,CuO负载量3%,床层温度120℃.在最佳工艺条件下,脱硫剂经热循环再生3次,采用未再生和再生脱硫剂后,试样脱硫率均随脱硫时间及再生次数增加而降低,但下降速度较为缓慢,且二者脱硫后产品收率和油品总收率分别大于84%,92%.