Oxidation of drying oils

Driers. These are generally soaps of cobalt, manganese, and other metals formed with organic acids such as linoleic, naphthenic, and other organic acids. They catalyze oxidation of drying oils (qv), and thus are used in inks that dry by oxidation (see Driers and metallic soaps). 

Oyman, Z.O. W. Ming R. Van Der Linde. Oxidation of drying oils containing non-conjugated and conjugated double bonds catalyzed by a cobalt catalyst. Prog. Org. Coat. 2005, 54, 198-204. 

Oxidation. Inks that dry by oxidation behave much like oil paint films and dry by means of the reaction of drying oils (qv) with oxygen. They contain metallic driers, which catalyze the absorption of oxygen by the drying oil (see Driers and metallic soaps Paint). 

Alkyds These are the most widely used of all air-oxidizing coatings and have the broadest use both industrially and domestically. They are usually classified according to the proportion of drying oil to synthetic resin (known as oil length ). The oil length influences all properties (e.g. chemical resistance, viscosity, flexibility and hardness). 

Development of the third class, i.e. unsaturated polyester resins, remained rather slow until the late 1930s, but after commercial production of maleic anhydride by catalytic oxidation of benzene began in 1933, maleic anhydride and fumaric acid rapidly became the most important sources of unsaturated groups in polyesters. The mechanism of drying of these resins on their own and with the addition of drying oils (i.e. unsaturated compounds such as linseed oil) was... 

Bielefeld s Gelotinizotion Method, patented in Germany in 1896-7, consisted of treating expls, such as NG, nitrobenzene, nitromolasses, aromatic nitrocompds, etc per se or in the presence of drying oils, resins, alcohol, etc with sulfur monochlor-ide(S2Cl2) at very low temps. The resulting jelly was mixed with oxidizers, such as nitrates, and with fuels, such as sawdust, flour, etc and then cartridged(compare with Parke s Absorbents)... 

For vapor phase measurement of dry oil oxidation, the plate assembly shown in Figure 5 is used. The lower glass or terephtha-late plastic plate holds a disk of polyamide (1.2 x 0.1 cm) on which 1 pi of a suitable oil (linoleic acid, methyl linoleate, cottonseed oil) is deposited from a micropipette. A Buna "0" ring of 1.5-mm thickness is placed surrounding the spot and a similar plate with a polyamide disk is inverted over the ring forming a tight seal when clamped with "C" clamps. The plate assembly is placed in a 65°C draft oven with the receiver plate bottommost. 

We described (34) use of the test in abused frying oils. We have patented an application to in-package detection of oxidative quality loss. We have studied in this manner the relative effectiveness of antioxidants in a thin layer of dry oil. 

During this process, the position and geometry of the double bond may change. The hydroperoxide mixtures produced by autoxidation and photooxidation are not the same, indicating that different mechanisms are involved. Free radical oxidation can be promoted or inhibited. Deliberate promotion speeds the polymerization of drying oils, and strenuous efforts are made to inhibit the onset of rancidity in edible oils. Frankel has recently reviewed this topic in depth (41) see also (1) for an extensive discussion of oxidation of food lipids. 

It has been demonstrated that tocopherols in hnoleic safflower oil were more stable than tocopherols in oleic safflower oil (150). The USDA did room odor studies that showed that oleic safflower did well compared with all other oils used in the study (151). A broad study was conducted of the effects of various substances on the oxidation of safflower oil in deep frying (152) of high temperature reactions in the presence of amino acids (153) and of the effect of amino acids on emulsions (154), dried emulsions (155, 156), and chemical and organoleptic properties (155, 156). 

Monolayer reactions have been studied for only twenty years. Striking applications have, however, already been made to other fields of investigation. Biological reactions, characterized by catalytic effects whose selectivity is similar to that of surface reactions, have become less mysterious. The mechanisms of the oxidation reactions in films of drying oils and of polymerization in emulsions of monomers have been clarified, although much remains to be done. It is the purpose of this review to show how novel and impressive are reactions taking place at liquid interfaces. 

The oxidation of linseed oil, which takes place in drying, is attended by the generation of much heat. If the oil is exposed in thin layers on porous inflammable material, such as cotton rags or waste, spontaneous combustion may take place as the result of active oxidation. Linseed oil dries more rapidly when exposed to the air if it has been previously boiled for some hours. The process consists in heating the oil with certain oxides or salts, called driers, such as litharge, lead acetate, or borate of manganese, which probably act as catalytic agents... 

Fish oils or fats are more unsaturated than beef or butterfat, and they are usuaUy classified as drying oils because they contain considerable proportions of highly unsaturated acids. The behavior of drying oils toward atmospheric oxygen is weU known, and oxidation is a serious problem for commercial drying of fatty fish and seafood. The fiesh of some fatty fish, such as herrings, contains a fat prooxidant that is not wholly inactivated by heat [5]. 

Oxyns n. Name given to the oxidation products of drying oils, which are obtained by the addition of oxygen to the double bonds of the unsaturated fatty acids. 

Yellowing (1598) v. Development of a yellow color on aging most noticeable in the dried films of white paints or clear varnishes. Primary cause of yellowing is the formation of color bodies due to oxidation of the oil or other unsaturated components of the binder. 

Partanen, R., Raula, J., Seppanen, R., Buchert J., Kauppinene, E., Forssell, P., 2008. Effect of relative humidity on oxidation of flaxseed oil in spray dried whey protein emulsions. J. Agric. Food Chem. 56 5717—5722. 

---