Potential as lubricants

Perfluoroalkyl-l,3,5-triazines are very stable to oxidation and heat. They have potential as lubricating fluids for use in aerospace work (B-74MI22003). Their polymeric products are stable elastomers with excellent rubber-like properties for use as electrical wire insulation and seals for hydraulic, lubricating and fuel systems of aircraft (B-80MI22001). Perfluoro-2,4,6-tri-n-heptyl-l,3,5-triazine is a valuable reference standard for precise mass... 

Recently, room temperature ionic liquids (RT-ILs) have attracted much attention for their excellent properties, e.g., wide temperature range of liquid phase, ultra-low vapor pressure, chemical stability, potential as green solvents, and high heat capacities [64,65]. These properties make them good candidates for the use in many fields, such as thermal storage [66], electrochemical applications, homogeneous catalysis [67], dye sensitized solar cells [68], and lubricants [69,70]. 

The system used in the simulations usually consists of solid walls and lubricant molecules, but the specific arrangement of the system depends on the problem under investigation. In early studies, hard spherical molecules, interacting with each other through the Lennard-Jones (L-J) potential, were adopted to model the lubricant [27], but recently we tend to take more realistic models for describing the lubricant molecules. The alkane molecules with flexible linear chains [28,29] and bead-spring chains [7,30] are the examples for the most commonly used molecular architectures. The inter- and intra-molecular potentials, as well as the interactions between the lubricant molecule and solid wall, have to be properly defined in order to get reliable results. Readers who intend to learn more about the specific techniques of the simulations are referred to Refs. [27-29]. 

Most hydraulic fluid preparations start as chemical mixtures. For instance, there is a considerable area of overlap in the specific petroleum hydrocarbon chemicals contained in the mineral oil and polyalphaolefin hydraulic fluids. For all classes of hydraulic fluids, there may be similarities with other original products intended for use as lubricants. The complications involved in documenting the environmental fate of mixtures increase under conditions encountered at many NPL sites, where it may be hard to determine the precise original product associated with chemicals identified at an area in need of remediation. In most instances, available peer-reviewed literature, supplemented with data obtained from manufacturers of particular formulations and information in trade magazines, can supply information about the original hydraulic fluid preparations. At NPL sites, site-specific evaluations of specific chemicals may be the only feasible way to address concerns over environmental fate and potential exposure risks. 

Very little research has been conducted on the potential application of ILs as lubricants or heat transfer fluids. ILs have the potential to compete with even the most successful synthetic organic and silicone-based compounds in the market. 

An atom or molecule that approaches the surface of a solid always experiences a net attractive potential ). As a result there is a finite probability that it is trapped on the surface and the phenomenon that we call adsorption occurs. Under the usual environmental conditions (about one atmosphere and 300 K and in the presence of oxygen, nitrogen, water vapor and assorted hydrocarbons) all solid surfaces are covered with a monolayer of adsorbate and the build-up of multiple adsorbate layers is often detectable. The constant presence of the adsorbate layer influences all the chemical, mechanical and electronic surface properties. Adhesion, lubrication, the onset of chemical corrosion or photoconductivity are just a few of the many macroscopic surface processes that are controlled by the various properties of a monolayer of adsorbates. 

A number of new processes exploiting metathesis have been developed by Phillips. A novel way to manufacture lubricating oils has been demonstrated.145 The basic reaction is self-metathesis of 1-octene or 1-decene to produce Ci4-C28 internal alkenes. The branched hydrocarbons formed after dimerization and hydrogenation may be utilized as lubricating oils. Metathetical cleavage of isobutylene with propylene or 2-butenes to isoamylenes has a potential in isoprene manufacture.136,146 High isoamylene yields can be achieved by further metathesis of C6+ byproducts with ethylene and propylene. Dehydrogenation to isoprene is already practiced in the transformation of isoamylenes of FCC C5 olefin cuts. 

Most lubricating oils for engine use contain additives designed to improve such properties as lubricity, detergency, oxidation resistance, and viscosity. The additives contain elements that could be potentially harmful to catalysts. Table I lists these elements and their typical concentration in lubrication oils of 1973. The first three elements are combined usually in one compound, zinc dialkyldithiophosphate. Thus, before combustion, sulfur and phosphorus in oil are in a different chemical state than the same elements are in fuel. Little is known whether combustion nullifies these differences partially or fully. Some data, to be discussed subsequently, are available on the separate poisoning effects of these elements as derived either from the fuel or from the oil. 

Pldbielniak Silicone Stopcock grease Contains silicone and carbon particles as lubricants, which may provide a more slippery lubricant. Because of the carbon, it should not be used with Teflon because there is a potential of scratching the Teflon. It should also not be used with compressed oxygen as it could detonate. 

The oxide and ceramic binders have been studied by several research groups, but do not seem to have been much used in practice or made commercially available. They are a rather heterogeneous group with considerable theoretical potential, being capable of withstanding temperatures of the order of 1000° compared with 400°C for molybdenum disulphide. There has therefore been a tendency to use the ceramics and oxides themselves as lubricants to retain the best high-temperature capabilities. 

Glycerol carbonate (Figure 5.6) can be prepared from glycerol via a number of routes, including its reaction with dimethyl carbonate catalysed by lipase enzymes. " It has potential as a biosolvent for coatings, cosmetics and pharmaceuticals, and as a lubricant. However, as it is a relatively new material in the chemical industry, limited data are currently available. 

Service tests have not always confirmed the potential as high-temperature lubricant fluids one would expect from silicones on the basis of their properties and their behavior in laboratory investigations. As early as 1946 a study by Fitzsimmons, Pickett, Militz and Zisman [22]... 

Fueling this interest in LB films is the commercial potential of these thin films as part of the microelectronics revolution that calls for ultrathin fabrication methods. The first international conference on LB films was held in 1979 and since then the use of this technique has been increasing worldwide. LB films have been utilized in many applications such as lubrication, wetting, adhesion, electronics, and construction of chemical, physical, and biological sensing devices (Roberts, 1990). 

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