Antioxidants addition

Antioxidant additives can not totally prevent the oxidation phenomenon, especially with the modern trend in oil-change intervals at the end of the interval, oil contains a significant quantity of insoluble oxidized material. 

Polymer-type antioxidants have been prepared by Eriedel-Crafts reaction of -cresol andp- and/or y -chloromethylstyrene in the presence of boron trifluoride-etherate (198). The oligomeric product resulting from the alkylation of phenyl-a-naphthylamine using C12—15 propylene oligomer in the presence of AlCl or activated white clays is used as an antioxidant additive for lubricating oils (199). 

AGE-Gontaining Elastomers. The manufacturing process for ECH—AGE, ECH—EO—AGE, ECH—PO—AGE, and PO—AGE is similar to that described for the ECH and ECH—EO elastomers. Solution polymerization is carried out in aromatic solvents. Slurry systems have been reported for PO—AGE (39,40). When monomer reactivity ratios are compared, AGE (and PO) are approximately 1.5 times more reactive than ECH. Since ECH is slightly less reactive than PO and AGE and considerably less reactive than EO, background monomer concentration must be controlled in ECH—AGE, ECH—EO—AGE, and ECH—PO—AGE synthesis in order to obtain a uniform product of the desired monomer composition. This is not necessary for the PO—AGE elastomer, as a copolymer of the same composition as the monomer charge is produced. AGE content of all these polymers is fairly low, less than 10%. Methods of molecular weight control, antioxidant addition, and product work-up are similar to those used for the ECH polymers described. 

Isopropyl Ether. Isopropyl ether is manufactured by the dehydration of isopropyl alcohol with sulfuric acid. It is obtained in large quantities as a by-product in the manufacture of isopropyl alcohol from propylene by the sulfuric acid process, very similar to the production of ethyl ether from ethylene. Isopropyl ether is of moderate importance as an industrial solvent, since its boiling point Hes between that of ethyl ether and acetone. Isopropyl ether very readily forms hazardous peroxides and hydroperoxides, much more so than other ethers. However, this tendency can be controlled with commercial antioxidant additives. Therefore, it is also being promoted as another possible ether to be used in gasoline (33). 

Antioxidant additive in the polyethylene resin. While such an additive can prevent oxidation, and thus odor, it also can contribute directly to the odor. If an antioxidant is needed, it must be FRA approved, should have a high melting point, and should be used at a minimum level consistent with the extrusion process. Catalyst residues and antioxidants present in polyethylene sometimes interact to form odorous products. 

A. Abbadi, K.F. Gotlieb, J.B.M. Meiberg and H. van Bekkum, New food antioxidant additive based on hydrolysis products of lactose. Green Chemistiy 5 (2003) 47. 

A GC-IR-MS system with library search capability has been used to effectively identify the pyrolysis products of polybutadiene and the antioxidant additive 2,6-di-f-butyl-4-methylphenol [199]. Paper for food packaging was analysed by P T (at 100 °C) combined with /i-GC-UV. No specific applications of /rGC-UV to poly-mer/additive analysis have as yet been reported. 

Adducts other than N bases are thiourea,909 phosphine,880 and N,0-donors (hydroxyquinoline derivatives).910 In the last case NiONS2 complexes were formed. Generally, complexes of dithiophosphates are used as antiwear and antioxidant additives. 

Figure 4. Loss of solubility of Du Pont Elvacite 2046, a 1 1 copolymer of n-butyl and isobutyl methacrylate, with and without UV absorber and antioxidant additives...

Sulfur(II)-containing compounds possess the reducing activity and react with hydroperoxides and peroxyl radicals [1-5]. They are employed as components of antioxidant additives to lubricants and polymers [30-35]. Denison and Condit [36] were the first to show that dialkyl sulfides are oxidized by hydroperoxides to sulfoxides and then to sulfones... 

Marcato, B., Guerra, S., Vianello, M. and Scalia, S. (2003). Migration of antioxidant additives from various polyolefinic plastics into oleaginous vehicles, Int. J. Pharm., 257, 217-225. 

From comparison with the results of charge trapping and anion BSD experiments on pure and doped -hexane films [32] (see as an example Fig. 13), it has been suggested that negative charging between 7 and 15 eV in XPLE is dominated by DBA to alkane chains. In contrast, charging below 5 eV is likely to be associated with molecular impurities (water, O2, and antioxidant additives) since pure alkane molecular solids are unable to trap electrons at these energies (Fig. 13). 

Zinc Zinc dithiophosphate-antiwear/antioxidant additive in most engine oils and industrial oils... 

Artifact formation during the extraction is demonstrated. The effect ofNi flushing and of antioxidant addition is shown. 

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. 

The crown-ether compounds as boundary lubricants and antioxidation additives. On the sliding surface, bromobenzo-15-crown-5 coordinates with ferrous ions and forms a strong reaction layer which protects the underlying metal surface. In the base stock solution, the crown ring can capture the metal ions which catalyze the oxidation of oil formulation (Brois and Gutierrez, 1987, 1989, 1992 and 1994 Le Suer and Norman, 1965 and 1966 Moreton, 1998). Bromobenzo-15-crown has excellent antiwear, antifriction and antioxidation properties, better than the ZDDP tested. 

The antiwear and antioxidant additive, zinc dialkyldithiophosphate, is a key ingredient in the great majority of engine oil formulations, and other lubricant applications such as hydraulic fluids and gear oils. The ZDDP-derived tribochemical films have been studied by a number of laboratories, but their mode... 

Antioxidant additives DBPC = 2,6-di-tert-butyl-p-cresol, B = alkyl-diphenyl amine Extreme-pressure additives DBDS = dibenzyl disulfide (C6H5-CH2-S-S-CH2-C6H5 ), DPDS = diphenyl disulfide (C6H5-S-S-C6H5) ... 

After a short period of use in the average engine, changes start to occur. Initially, a loss of the zinc based antiwear/antioxidant additive ZDDP is observed by negative absorptions at 1000 cm 1 and 715 cm 1. Oxidative degradation of oil follows soon after and this is observed by positive absorptions, represented by carbonyl, hydroxy, nitro and C-O- species. The ER spectroscopy of lubricants can reflect additive depletion and the formation of oxidation products (Coates and Setti, 1984 Coates etal., 1984). 

ZEVs ZDDP Zero emission vehicle. Zinc dialkyldithiophosphate, a widely used antiwear and antioxidant additive for motor oils and industrial fluids also referred to as ZDTP, ZDP, and "zinc". 

Hess, M.A., Haas, M. J., Foglia, T. A., and Marmer, W. M. 2005. Effect of Antioxidant Addition on NOx Emissions from Biodiesel. Energy Fuels, 19,1749-1754. 

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. 

Certain performance limitations of vegetable oil basestocks are poor oxidative stability due to bis-allylic protons in the fatty acyl chain, deposit forming tendency, low-temperature solidification, and low hydrolytic stability. Oxidation results in increased acidity, corrosion, viscosity, and volatility of the lubricant. On the other hand, parameters like lubricity, antiwear protection, load carrying capacity, mst prevention, foaming, demulsibility, etc., are mostly additive dependent. Antioxidant additives (4) provide limited improvement of oxidative stability therefore, other approaches are required to improve the above characteristics. 

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