Lubricants viscosity index

Also in the acrylate family, n-butyl methacrylate is produced by the same process as methyl methacrylate -alcoholysis of methacrylamide with n-butanol. There are two major applications for n-butyl methacrylate - as a modifier in polymers for industrial and automotive lacquers and as a comonomer with higher methacrylates (e.g., lauryl and stearyl) in the manufacture of lubricant viscosity index improvers. 

The monodispersity, the large number of surface functionalities, and the unique rheological properties make dendrimers and hyperbranched polymers potential candidates for a variety of applications such as biosensing [249], catalysis [250], gene therapy [251], and lubricant viscosity-index (VI), just to name a few. However, the mechanochemistry of dendrimers and hyperbranched polymers remains little understood. 

Ye and co-workers exploited the shear stability of highly branched, high molecular weight polyethylenes (PEs) as lubricant viscosity index improvers [252, 253]. Viscosity index of a lubricant is a critical parameter which defines its quality and application temperature range. They synthesized PEs with controllable chain topologies ranging from linear to a hyperbranched dendritic structure by chain walking polymerization [254]. The PE samples were blended into a base paraffinic oil (density 0.8659 g mL at 15 °C, kinematic viscosity 30.06 cST at 40 °C) to form lubricants. The lubricants were subjected to the Kurt Orbahn (KO) test to measure the shear stability index, which is expressed by... 

Morgan S, Ye Z, Subramanian R, Zhu S (2010) Higher-molecular-weight hyperbranched polyethylenes containing crosslinkmg structures as lubricant viscosity-index improvers. 

Wang J, Ye Z, Zhu S (2007) Topology-engineered hyperbranched high-molecular-weight polyethylenes as lubricant viscosity-index improvers of high shear stability. Ind Eng Chem... 

Motor performance Lubrication properties Constant viscosity (viscosity index) Fluidity at low temperature Proper viscosity at high temperature... 

The viscosity of a hydrocarbon mixture, as with all liquids, decreases when the temperature increases. The way in which lubricant viscosities vary with temperature is quite complex and, in fact, charts proposed by ASTM D 341 or by Groff (1961) (Figure 6.1) are used that provide a method to find the viscosity index for any lubricant system. Remember that a high viscosity index corresponds to small variation of viscosity between the low and high... 

A refinery lubricant base stock is obtained having an viscosity index around 100, certain hydrotreatments result in Vi s of 130, and paraffin hydroisomerization provides oils with a VI close to 150. 

Consider that at low temperatures, a lubricant is a poor solvent for polymer chains. When the temperature increases, interactions between polymer chains decrease the space occupied by the polymer ball takes on greater volume and consequently, the viscosity decrease due to the lubricant temperature increase is compensated by the unfolding of the polymer chain and the result is a reduction of the difference between the viscosities at low and high temperature, and therefore an Increase in viscosity index. 

In a single stage, without liquid recycle, the conversion can be optimized between 60 and 90%. The very paraffinic residue is used to make lubricant oil bases of high viscosity index in the range of 150 N to 350 N the residue can also be used as feedstock to steam cracking plants providing ethylene and propylene yields equal to those from paraffinic naphthas, or as additional feedstock to catalytic cracking units. 

Lubricants, Fuels, and Petroleum. The adipate and azelate diesters of through alcohols, as weU as those of tridecyl alcohol, are used as synthetic lubricants, hydrauHc fluids, and brake fluids. Phosphate esters are utilized as industrial and aviation functional fluids and to a smaH extent as additives in other lubricants. A number of alcohols, particularly the Cg materials, are employed to produce zinc dialkyldithiophosphates as lubricant antiwear additives. A smaH amount is used to make viscosity index improvers for lubricating oils. 2-Ethylhexyl nitrate [24247-96-7] serves as a cetane improver for diesel fuels and hexanol is used as an additive to fuel oil or other fuels (57). Various enhanced oil recovery processes utilize formulations containing hexanol or heptanol to displace oil from underground reservoirs (58) the alcohols and derivatives are also used as defoamers in oil production. 

The products manufactured are predominantiy paraffinic, free from sulfur, nitrogen, and other impurities, and have excellent combustion properties. The very high cetane number and smoke point indicate clean-burning hydrocarbon Hquids having reduced harmful exhaust emissions. SMDS has also been proposed to produce chemical intermediates, paraffinic solvents, and extra high viscosity index (XHVI) lubeoils (see Lubrication and lubricants) (44). 

Alkylated aromatics have excellent low temperature fluidity and low pour points. The viscosity indexes are lower than most mineral oils. These materials are less volatile than comparably viscous mineral oils, and more stable to high temperatures, hydrolysis, and nuclear radiation. Oxidation stabihty depends strongly on the stmcture of the alkyl groups (10). However it is difficult to incorporate inhibitors and the lubrication properties of specific stmctures maybe poor. The alkylated aromatics also are compatible with mineral oils and systems designed for mineral oils (see Benzene Toulene Xylenes and ethylbenzene). ... 

The low molecular weight materials produced by this process are used as lubricants, whereas the high molecular weight materials, the polyisobutylenes, are used as VI improvers and thickeners. Polybutenes that are used as lubricating oils have viscosity indexes of 70—110, fair lubricating properties, and can be manufactured to have excellent dielectric properties. Above their decomposition temperature (ca 288°C) the products decompose completely to gaseous materials. 

Practically all lubricating oils contain at least one additive some oils contain several. The amount of additive that is used varies from < 0.01 to 30% or more. Additives can have detrimental side effects, especially if the dosage is excessive or if interactions with other additives occur. Some additives are multifimctional, eg, certain VI improvers also function as pour-point depressants or dispersants. The additives most commonly used in hydrautic fluids include pour-point depressants, viscosity index improvers, defoamers, oxidation inhibitors, mst and corrosion inhibitors, and antiwear compounds. 

Lubricants. Petroleum lubricants continue to be the mainstay for automotive, industrial, and process lubricants. Synthetic oils are used extensively in industry and for jet engines they, of course, are made from hydrocarbons. Since the viscosity index (a measure of the viscosity behavior of a lubricant with change in temperature) of lube oil fractions from different cmdes may vary from +140 to as low as —300, additional refining steps are needed. To improve the viscosity index (VI), lube oil fractions are subjected to solvent extraction, solvent dewaxing, solvent deasphalting, and hydrogenation. Furthermore, automotive lube oils typically contain about 12—14% additives. These additives maybe oxidation inhibitors to prevent formation of gum and varnish, corrosion inhibitors, or detergent dispersants, and viscosity index improvers. The United States consumption of lubricants is shown in Table 7. 

Synthetic lubricants are tailored molecules which have a higher viscosity index and a lower volatiUty for a given viscosity than lube oils from... 

Poly(alkylene glycol)s have a number of characteristics that make them desirable as lubricants. Compared to petroleum lubricants, they have lower pour points, a higher viscosity index, and a wider range of solubilities including water, compatibility with elastomers, less tendency to form tar and sludge, and lower vapor pressure (35). 

An example of an appHcation of hydrocracking is in lubricating oils, where it is used to improve the viscosity index, color, and color stabiHty to reduce polymer formation (storage stabiHty) and to decrease the neutralization number (acidity) (61). 

Additives for lubricating oils providing a combination of viscosity index improvement (VII) and dispersancy have also been reported. These additives are prepared from ethyleneamines by reaction with various Vll-type polymers that have been chlorinated or modified in some other way to provide an ethyleneamine reaction site. Antimst additives for lubricating oils have been prepared by reaction of polyamines with fatty acids followed by reaction with polyalkylenesuccinic anhydrides (178,179). 

Universal at 100° F) and a viscosity index of 95. They contain necessary oxidation inhibitors and antiwear agents, as the same oil is used for bearings and gear lubrication. Oils tend to retain water, either from steam condensation or from condensation that occurs in the tanks. The presence of water is detrimental as it encourages the for-... 

This technology has been utilized by BP Chemicals for the production of lubricating oils with well defined characteristics (for example, pour point and viscosity index). It is used in conjunction with a mixture of olefins (i.e., different isomers and different chain length olefins) to produce lubricating oils of higher viscosity than obtainable by conventional catalysis [33]. Unichema Chemie BV have applied these principals to more complex monomers, using them with unsaturated fatty acids to create a mixture of products [34]. 

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