Metallic detergents

The WTD is a cumulative rating based on observation of deposits in the groove and land areas of the piston and lacquer on piston skirts which have been weighted and calculated in accordance with the test procedure. The evalated lubricating oils also contained, where required, conventional viscosity improver, a metal detergent and ZDDP in mineral base oil. The WTD ratings were as follows ... 

Mixtures of metallic detergents, such as phenates, sulfonates, phosphonates, and salicylates with ashless dispersants such as succinimides and benzylamine, together with zinc dialkyldithiophosphate (ZDDP), can lead to new effects. The possible interactions between these main additives used in lubricating formulations when dissolved/dispersed in hydrocarbon media are shown in Fig. 2.8 together with an indication of the intensity of those respective interactions. 

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. 

Some investigators have shown that mixtures of succinimides, sulfonates, phenolates and salicylates produce acid-base complexes which tend to form aggregations (Inoue and Watanabe, 1983 Vipper and Watanabe, 1981). The intermolecular interactions between ashless dispersants (PIBS) and metallic detergents were found to decline in the following order ... 

The aggregation number of metallic detergents varies with length and structure of the hydrocarbon groups, the type of the cation, and the polarity of the solvent. The aggregation number of sodium, magnesium, calcium and barium dinonyl-naphthalene sulfonates in hydrocarbon solvents lies between 10 and 15 and is twice that of nonylphenates (Fowkes, 1962 Heiweil, 1964 Inoue and Watanabe,... 

A combination of ZDDP and hard-core RMs leads to a synergistic effect of metallic detergents on the degradation of ZDDP. These phenomena are observed in many tests and can be explained in terms of (a) the acid neutralization property of hard-core RMs that leads to the prevention of decomposition of ZDDP (in the valve train wear test and the thin film oxygen uptake test), (b) the competitive adsorption of detergents that reduce the effective concentration of ZDDP on the metal surface (in the four-ball test), (c) the formation of mixed films on the metal surface, formed through the decomposition of ZDDP in the presence of hard-core RM s (the coefficient of friction in the Falex wear test). 

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. 

The storage container must be free from contamination before use. A solution of strong non-metallic detergent may be used for most applications. After soaking in detergent for a time, rinse the container with tap water, then distilled or deionised water. Dry in an oven at approximately 50°C before use. The use of air-jet drying after application of a volatile solvent, such as acetone, often gives rise to contamination. 

Basic metal detergents are made in a manner similar to forming the neutral detergent. The metal hydroxides used in these basic detergents are typically divalent in character. For example, calcium, magnesium or barium, have been used however, monovalent sodium versions can also be made. The basic detergent illustrated below contains 100% more base (on a chemical equivalent basis) than a neutral detergent. Reaction (7.2) ... 

Two types of surfactants are used in engine oil applications. One is ashless dispersants, and the other is metallic detergents. Typical ashless dispersants, as described in Chapter 15 of Part D (Formulations) of the Handbook of Detergents [8], include succinimides, Mannich condensates, esters, phosphonates, functionalized ethylene-propylene copolymers, and others. Their molecular structures are shown in Figure 13.1. 

Commonly used metallic detergents in engine oils are sulfonates, phenates, salicylates, and others. Example of these three types of metallic detergents are shown in Figure 13.4. 

FIGURE 13.4 Example of metallic detergents used in engine oils. 

Some metallic detergents, such as sulfonates, in particular the overbased sulfonates, function as a rust inhibitor by forming a film through adsorption of surfactant molecules or neutralizing the acidic materials, preventing them from attacking the metal surfaces. Acidic materials are commonly produced by incomplete combustion of fuels or oil oxidation. 

Industrial lubricants include metalworking lubricants, industrial greases, industrial lubricants, transformer oils, hydraulic oils, refrigeration oils, turbine oils, compressor oils, rock drill lubricants, paper machine oils, way lubricants, and railway journal box oils. The required additive package for each of these industrial oils is different depending on its specific application. Unlike lubricants used in automotive lubrication, industrial lubricants typically do not use metallic detergents and ashless dispersants as additives to keep metal surfaces clean and prevent insoluble materials from formation of deposits on metal surfaces [23]. However, in recent years the use of overbased detergents to supplement performance of the antiwear additive zinc dialkyl dithiophosphate has been reported [24]. 

However, metallic detergents, such as calcium sulfonate, are often used as rust inhibitors to prevent or reduce rusting on the metal parts. Moisture due to machine operating conditions, for example in circulating systems of steam turbines, steel mills, and paper machines, may be present either as free water or as entrainment in the lubricant. Rust inhibitors function by formation of a protective oil film on the surfaces [25] the film effectively separates the water from the metal surfaces. 

Najman, M., Kasrai, M., Bancroft, G.M., Davidson, R. Combination of adless antiwear additives with metallic detergents interactions with neutral and overbased calcium sulfonates. Tribol. Int. 39, 342-355 (2006). doi 10.1016/j.triboint.2005.02.014... 

Dehypon LS104 L Dehypon LS 104 Dehypon LS 531 Dehypon LT104 L Dehypon LT 104 Dehypon 0 54 Luten-sit A-BO Macol LF-111 Octoxynol-9 Synperonic LF/RA30 Synperonic LF/ RA260 Tegotens 475 surfactant, metal detergents UnitollD30... 

Burcoterge GRN Burcoterge HBC wetting agent, aluminum/metal detergents... 

Teric 612A6 Teric G12A8 Teric 612A12 Teric LA8 wetting agent, metal detergents... 

Alkali Metal Detergents and Soaps A detergent is a cleansing agent used primarily because it can emulsify oils. Although the term detergent includes common soaps, it is used primarily to describe certain synthetic products, such as sodium lauryl sulfate, whose manufacture involves the following conversions. 

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