Reactions in oil formulation

Tribochemical interactions of acid-base in tribosystem have been observed at two levels (i) acid-base reaction in oil formulation and (ii) acid-base reaction on metal surfaces. 

Eor water-based alkyd paints, greater (0.2% cobalt on a resin basis) concentrations of drier are required than for other systems because the reaction of the drier with water decreases the activity of the catalyst. The cobalt content of oil-based paint formulations is usually 0.01—0.05% cobalt. Although the concentration of cobalt in the formulations is small, the large volume of paints, inks, and varnishes constitute a significant use for cobalt chemicals. 

Besides the alkyl ether carboxylates the amidether carboxylates are used as mild surfactants in cosmetic formulations [35-37,68,69,71,80]. As described by Meijer [68,69], the ether carboxylate mixture derived from the monoethanol-amide of coconut oil is a mild product in shampoos and showerbaths, and the stearylmonoethanolamidether carboxylate an oil-in-water emulsifier for creams and lotions. The NDELA content of these products is below the detection level of 10 ppb because of the use of monoethanolamine and the further chemical reactions after amidation. 

Gutfelt et al. (1997) have evaluated various ME formulations as reaction media for synthesis of decyl sulphonate from decylbromide and sodium sulphite. The reaction rate was fast both in water-in-oil and in bicontinuous ME based on non-ionic surfactants. A comparison was made with this reaction being conducted in a two-phase. system with quats as phase-transfer catalyst but was found to be much less efficient. However, when two other nucleophiles, NaCN and NaNOj, were used the PTC method was almost as efficient as the ME media. It seems that in the case of decyl sulphonate there is a strong ion pair formation between the product and the PTC. The rate in the ME media could be further increased by addition of a small amount of a cationic surfactant. 

Hypersensitivity reactions A few patients receiving the injection have experienced anaphylactic reactions. Although the exact cause of these reactions is not known, other drugs with castor oil derivatives in the formulation have been associated with anaphylaxis in a small percentage of patients. 

This chapter focuses on silica synthesis via the microemulsion-mediated alkoxide sol-gel process. The discussion begins with a brief introduction to the general principles underlying microemulsion-mediated silica synthesis. This is followed by a consideration of the main microemulsion characteristics believed to control particle formation. Included here is the influence of reactants and reaction products on the stability of the single-phase water-in-oil microemulsion region. This is an important issue since microemulsion-mediated synthesis relies on the availability of surfactant/ oil/water formulations that give stable microemulsions. Next is presented a survey of the available experimental results, with emphasis on synthesis protocols and particle characteristics. The kinetics of alkoxide hydrolysis in the microemulsion environment is then examined and its relationship to silica-particle formation mechanisms is discussed. Finally, some brief comments are offered concerning future directions of the microemulsion-based alkoxide sol-gel process for silica. 

The additive mixtures interact in a variety of ways, both in the bulk oil and on surfaces. Tribochemical interactions of additives in the oil formulation are discussed in Chapter 2. Surfactant molecules, when dissolved in base oil, are capable of self-organization to form aggregates such as soft-core reverse micelles (RMs). The polar or charged head groups of these molecules with the counter ions form the interior of the micelle (core), and the hydrocarbon chains made up its external shell. The most important factor governing the tribochemical reactions under boundary lubrication is connected with the action of soft-core and hard-core reverse micelles discussed in Chapter 3. 

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. 

Acid-base reactions in hydrocarbon oil formulations and low polar media can be formulated as acid-base association constants between an acid and base ... 

Deveaux et al. [21] reported that mefenamic acid, being an N-aryl derivative of anthranilic acid, can be characterized by two color reactions. The color reactions, negative with N-aryl derivatives of aminonicotinic acid, are associated with the diphenylamine structure. For the first color reaction, add to a test tube approximately 0.5 g of oxalic acid dihydrate and at least 1 mg of the test material. Place the tube into an oil bath at 180-200°C for 4-5 min. After cooling, dissolve the residue in 10 mL of 95% ethanol to obtain a stable, intense blue solution (absorption maximum at 586-590 nm). To use the reaction for capsule formulations, extract the active ingredient with acetone and filter prior to the assay. For the second color reaction, add mefenamic acid (100-800 pg) in 1 mL of H0Ac-H2S04 (98 2, v/v), 5 mL of HOAc-HCl (50 50, v/v) and 1 mL of 0.10% (w/w) aqueous levulose. Heat the mixture for 25 min at 100°C, and after cooling, measure the absorbance at 597 nm. 

Organic reactions in micro emulsions need not be performed in one-phase systems. It has been found that most reactions work well also in two-phase Winsor I or Winsor II systems, i.e. an oil-in-water microemulsion coexisting with excess oil or a water-in-oil microemulsion coexisting with excess water, respectively [7, 8]. A Winsor III system, i.e. a three-phase system in which a middle phase microemulsion coexists with both oil and water, has also been successfully used as reaction medium [9]. The transport of reactants from the excess oil or water phase to the microemulsion phase, where the reaction takes place, is evidently fast compared to the rate of the reaction. This is a practically important aspect on the use of micro emulsions as media for chemical reactions because it simplifies the formulation work. Formulating a Winsor I or Winsor II system is usually much easier than formulating a one-phase microemulsion of the whole reaction mixture. Winsor systems can also be of value to simplify the work-up process, in particular to separate the product from the surfactant, as will be discussed below in Sect. 2.4 (see also [6]). 

The photosensitized electron transfer reaction forms the reduced lipophilic electron acceptor BNA which is ejected into the continuous organic phase and thus separated from the oxidized product. In order to monitor the entire phase transfer of the reduced acceptor, BNA, a secondary electron acceptor, p-dlmethyl-amlnoazobenzene (dye),was solubilized in the continuous oil phase. The photochemically induced electron transfer reaction in this system results in the reduction of the dye (0 = 1.3 x 10 3). Exclusion of the sensitizer or EDTA or the primary electron acceptor, BNA, from the system resulted in no detectable reaction. Substitution of the primary acceptor with a water soluble derivative, N-propylsulfonate nicotinamide, similarly results in no reduction of the dye. These results indicate that to accomplish the cycle formulated in Figure 6A the amphiphilic nature of the primary electron acceptor and its phase transfer ability in the reduced form are necessary requirements. 

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