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The article describes the systematic studies on the lubrication properties of biodiesel, low sulfur diesel fuel, and their blends. Biodiesel from nonedible oils (e.g., Jatropha curcas, Pongamia glabra, Madhuca indica, and Salvadora oleoides) were prepared by base-catalyzed transesterification using methanol; high-speed diesel (HSD) used was from Panipat refinery. The lubricity evaluation of biodiesel and its blends (5-50%) was carried out as per the ISO-12156 method using high-frequency reciprocating rig (HFRR) test rig. The results indicate that addition of biodiesel to HSD improves the lubricity and provides a stable film on the metal surface. Addition of biodiesel substantially reduces wear scar diameter (WSD). The results were also comparable with pure ester-type compounds synthesized in our laboratory. We concluded that the preferred range of blending biodiesel is 5-20%. WSD of neat HSD is around 0.37 mm, whereas that of all four biodiesels is below 0.20 mm, which is around 50% or less than HSD used. The reduction in WSD at 5% blend is not appreciable except in the case of Salvadora biodiesel, which contains a high percentage of sulfur. At 20% level, around 45% reduction in WSD can be achieved.

A critical appraisal is made of the applications of vegetable oils, the fatty esters complex and synthetic esters as rapidly biodegradable and non-toxic lubricants and fuels in the developed countries of America, Europe and Asia.The criteria employed for assessing the toxicity and biodegradability of the various fluids and limits set by various state and regional organizations are reviewed. The properties of vegetable oils, fatty esters, chemically modified esters and synthetic esters relevant for performance as lubricants in various applications such as hydraulic oils, refrigeration oils, chainsaw lubricants, metalworking fluids, engine oils, two-stroke oils, mould release lubricants, greases, gear and transmission oils vis-à-vis conventional mineral oils and greases for corresponding applications are compared. The advantages, such as high lubricity, viscosity-temperature relationship, low lubricant consumption, energy efficiency combined with public health, safety and environmental contamination, more than offset the disadvantages of initial costs in most of these applications.It has been suggested that modified and stabilized oils of wasteland and forest origin and other non-edible oils and their chemically modified derivatives can be produced at relatively cheaper cost than similar oils marketed in the developed world and can be introduced in India with immense environmental and performance benefits, particularly in applications involving high environmental contamination safety and public health.When blended with highly refined diesel fuels, methyl esters can work as highly efficient environment-friendly fuels particularly for applications in passenger transport, light commercial vehicles and generators.

The bituminous crudes derived from tar sands as well as heavy crude oils are characterized by high viscosity, which poses problems during their pipeline transportation. These oils contain a significantly higher percentage of asphaltenes, which have polycondensed aromatic ring structures and tend to self-aggregate to produce a viscoelastic structure resulting in the high viscosity. Apart from blending and dilution to reduce viscosity, a method being explored is the addition of chemicals in small amounts that can hinder or alter the aggregation in such a way that the viscosity is reduced. In the present work, two novel gemini surfactants were synthesized in the laboratory by the reaction between 4-(dimethylamino) benzaldehyde and 1-bromododecane, which formed an intermediate compound in the first step. This intermediate compound was treated with 6-methyl-1,3,5-triazine-2,4-diamine to obtain the gemini surfactant N,N′-bis­{(p-(N,N,N-dodecyldimethylammonium chloride) benzylidene} 6-methyl-1,3,5-triazine-2,4-diamine, denoted as VRA-1 and separately with 6-phenyl-1,3,5-triazine-2,4-diamine to obtain N,N′-bis­{(p-(N,N,N-dodecyldimethylammonium chloride)­benzylidene} 6-phenyl-1,3,5-triazine-2,4-diamine, denoted as VRA-2. After confirming the structures of these synthesized products by elemental analysis (CHN), infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy, these were investigated for their viscosity reducing properties. Studies were carried out for their application as viscosity reducing agents (VRAs) in the bituminous crude obtained from high grade Canadian oil sands. This bituminuous crude was blended with toluene followed by doping of these surfactants in the dosage varying from 100 to 600 ppm. The rheological behavior of these was determined at temperatures of 20, 40, and 60 °C at variable shear rates. The studies indicated that these types of compounds can be effective as viscosity reducing agents for heavy crude oils. In the present case, VRA-2 has shown better performance as compared to VRA-1.

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