Detergent-dispersant

Additive packages have been developed which do an exceUent job of preventing IVD. The key to effective operation is to keep the valve wet so that the additive can prevent deposit buildup. Most packages include a combination of detergent/dispersant and a carrier oil or heavy solvent. If no carrier oil is present, then the fuel may evaporate off the valve too rapidly for the package to be effective. When the valves do not rotate, the portion of the valve which has the highest deposit level is the back side which is not constantly wet. 

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. 

R, mst inhibitor O, oxidation inhibitor D, detergent—dispersant VI, viscosity-index improver P, pour-point depressant W, antiwear EP, extreme pressure F, antifoam and M, friction modifier. 

Adenylyl Cyclases. Table 3 Nucleoside inhibitors of adenylyl cyclase. Assays were with a detergent-dispersed adenylyl cyclase from rat brain and were with 100 pM 5 ATn and 5 mM MnCI2 as substrates... 

There have been some examples of the use of LDMS applied to the analysis of compounds separated via TLC, although not specifically dealing with polymer additives [852]. Dewey and Finney [838] have described direct TLC-spectroscopy and TLC-LMMS as applied to the analysis of lubricating oil additives (phenolic and amine antioxidants, detergents, dispersants, viscosity index improvers, corrosion inhibitors and metal deactivators). Also a series of general organics and ionic surfactants were analysed by means of direct normal-phase HPTLC-LMMS [837]. Novak and Hercules [858] have... 

In addition, in fuel compositions or lubricating oil compositions, poly(isobutyl) N-substituted pyrrole compounds are particularly useful as a detergent-dispersants. The additives can be synthesized via a carbocationic polymerization (5). 

Moderate enrichments of activity have been reported following fractional precipitation and differential centrifugation of microsomal preparations treated with detergents (37, 70, 72, 78) or proteolytic enzymes (78), or fractional precipitation of detergent-dispersed microsomal preparations with acetone in the presence of Mg2+ (46, 81). 

Modern motor oil provides an example of some of the ways in which a number of colloidal and interfacial considerations come into play adhesion and lubrication, detergency, dispersion and suspension stabilization, foam inhibition, and viscosity and its temperature dependence. In addition to providing lubrication, a motor oil is expected to prevent corrosion and aid engine cooling and cleaning. Table 8.1 shows how a number of additives are blended in to help the oil achieve these functions [491]. 

B) Medium intermolecular interactions detergent-dispersant. In hydrocarbon formulations, the principal interaction between ashless dispersants (e.g., succinimide) and metallic detergents (e.g., phenate, salicylate and sulfonate) may be ascribed to the acid-base interactions between the anion of metallic detergents and the amino group of the succinimide as shown in Fig. 2.10. 

Detergent-dispersant interactions at surfaces. In 4-ball wear tests, an ashless dispersant was found to have an adverse effect on ZDDP-sulfonate-carbonate hardcore RM additives. A high molecular weight Schiff base had the worst effect, followed by a bis-PIBS m-PIBS had the least adverse effect. Interactions among additives affects valve train wear. One of the effects is that a succinimide together with other additives increases the decomposition temperature of ZDDP (Ramakamur, 1994 Shirahama and Hirata, 1989). 

Chemical parameters What is meant by chemical parameters in oil formulation Which of the following is a chemical parameter adsorption, detergent, dispersant, concentration, ZDDP, or surface roughness ... 

The typical detergent-dispersant additives used in modem lubricating oils are metallic detergents/sulfonates, phenolates, phosphonates, salicylates, ashless dispersants/succinimides and benzylamines. Water is solubilized by strong ion-dipole interactions. The solubilization of water (Watanabe, 1970) by hydrogen bond formation with succinimides and the amount solubilized is smaller than that solubilized by sulfonates. 

Influence of size and structure of a hydrocarbon radical of antioxidant and antiwear additives introduced in the oil composition on cuccinimide detergent-dispersion action is observed. The maximum solubilization effect takes place for the ramified and smaller-size radicals. Such an effect is discovered in the substances synthesized on the basis of... 

Influence of the obtained sulfur-containing substances and the shielded phenols on detergent-dispersive action of cuccinimide has been investigated. It has been established, that combination of antiwear and antioxidant additives in an oil composition with cuccinimide allows to appreciably reduce the contents of the latter to maintain sufficiently high operational characteristics of lubricants. 

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