Ashless additives

Where liquefied petroleum gas (LPG) engines are used in trucks or buses, oils for API Service SJ are often used for convenience, although somewhat lower quality oils may be satisfactory. In some cases, special oils containing no organometallic detergents (ashless additives) are recommended. 

Ashless additive development has reduced the risk of solid deposit formation and ashless dispersants, anti-oxidants and anti-foam agents are now permitted in most engines. Non-dispersant mineral oils are now used primarily for older aircraft and as a running-in oil for new engines or after overhaul. 

A Possibility to Use a Batch of Ashless Additives for Production of Commercial Transmission and Motor Oil... 

While the reactivity of new ashless additives with metal surfaces has been investigated quite extensively, less is known about the thermal degradation of these compounds in oil solution. As was the case for ZnDTPs [1, 3], investigating the reactions that take place in oil solution at high temperature could significantly contribute to elucidating the mechanism of thermal film and tribofilm formation on metal surfaces. 

Although ester chemistry has been studied extensively, new esters with unique performance improvements have continuously been reported in the literature . For example, esters with high stability were made from highly branched acids and polyols. Polyol esters formulated with ashless additives can be used as high performance biodegradable hydraulic fluids. 

Fuels and Lubricants. Rare-earth neodecanoates have been claimed as additives for diesel fuels that reduce the precipitation of particles and gum (108). Neodecanoic acid has also been used in the preparation of ashless detergent additives for fuels and lubricants that reduce engine deposits in internal combustion engines (109). 

In the presence of interfering elements, proceed as follows. Neutralise 80-120mL of the solution containing 15-25mg of beryllium with ammonia solution until the hydroxides commence to precipitate. Re-dissolve the precipitate by the addition of a few drops of dilute hydrochloric acid. Add 0.5 g of ammonium chloride and sufficient 0.5M EDTA solution to complex all the heavy elements present. Add a slight excess of dilute ammonia solution, with stirring, boil for 2-3 minutes, add a little ashless filter pulp, filter, and complete the determination as above. 

Indeed, in the work of Fitzgerald and Wilson (55), the introduction of tributyl phosphate into the oil gave a rather steep deterioration of hydrocarbon activity. A similar sharp deterioration was also noted when an unidentified ashless antioxidant additive by itself was employed. The conclusion reached by the authors is that the presence of phosphatebinding metals, mainly Zn and Ca, is responsible for the inhibition of the poisoning influence of phosphorus from engine oils. 

Lubricant additives (Ashless dispersant A and B, Zinc dialkyldithiophosphate) TT A (Ward et ah, 2002b)... 

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. 

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). 

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. 

Additive containing no metallic elements, e.g., ashless dispersant succinimides, succinate esters. 

If the solution or the filtrate from Group IIIB is brown or dark in colour, Ni may be suspected. The dark-coloured solution contains colloidal NiS, which runs through the filter paper. It may be acidified with acetic acid, and then boiled until the NiS has coagulated this may either be added to the Group IIIB precipitate or tested separately for Ni. As a general rule, the addition of macerated filter paper (e.g. in the form of a portion of a Whatman filtration accelerator or ashless tablet) to the suspension before filtration will lead to a clear or colourless solution. 

Many of the ashless anti-knocks are amines or phenols [26] and are related to liquid-phase oxidation inhibitors. They probably work by reacting with active radicals (particularly OH) to produce radicals which are inert. For instance, N-methyl aniline (NMA) CeHsNHCHs probably produces stabilized CeHsNCHs radicals which, because of their resonance stabilization, are unable to react to regenerate active radicals again and may undergo only radical recombination reactions. The rate of radical removal by this process is likely to be limited in the most favourable case by how fast the additive can react with OH to produce stabilized radicals. Although exact rates are not known, this is probably already a fast process for NMA, and unlikely to be very much faster for any other substance. Indeed, the most effective ashless anti-knock found by MacKinven [26] in an extensive study of 970 substances was a tetra-aryl hydrazine, with a molar effectiveness 2.9 times that of NMA. 

Use In lubricating-oil additives for ashless dispersant processing, rolling, and compressor oils caulks, sealants, adhesives as an elastomeric process aid and cling improver in cling films. 

Antioxidant technology To indicate the oxidation and thermal stability of a variety of ZnDTP-containing and ashless anti-wear hydraulic fluids, TOST and Cincinnati Milacron data - both relevant tests for this type of fluid - have been compiled and summarised. Table 4.9, from both published [80, 81] and in-house results. The data show that oxidation resistance and thermal stability of the premium fluids, both ashless and stabilised ZnDTP, are comparable and clearly outperform the normal-grade fluids. The normal ashless grade at 0.4-0.5% additives is superior to the normal ZnDTP-based grade, especially for thermal stability, which may be due to the use of thermally unstable secondary ZnDTPs. 

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