Miscellaneous Antioxidants

Koch [33] has also described visible colorimetric methods for the determination of phenolic antioxidants in HB 307 in the concentration range around 1 ppm. A method (Koch [33] utilising diphenyl-picrylhydrazyl as the chromogenic reagent has been applied to the determination of compounds such as 4,4 -butylidene-bis-(3-methyl-6-tert-butylphenol-l) and 2,2 -methylene-bis-(4-ethylene-6-tert-butyl phenol-1). In this method, 2 ml of an ethanolic solution (0.05 to 1 mg per 100 ml) of an antioxidant was added to 5 ml of a 50% solution of HB 307 in chloroform or 1,2-dichloroethane in a stoppered test-tube. Then 3 ml of 0.0075% ethanolic 2,2-diphenyl-l-picrylhydrazyl was added, and the stoppered tube was heated for 30 or 60 minutes (according to the antioxidant) in a water bath at 60 °C. 

Test film Identity and concentration (% w/v) of labelled additive Proportion (%) of radioactivity or additive migrating into Ratio for  

The tube was cooled in water at 20 °C, and, as soon as possible, the extinction of the solution was measured at 517 nm against a similarly prepared solution of a sample without antioxidant. The order of extinction measurement was the same as that of sample preparation, to give a standardised reaction time. Air was excluded in all operations, and all solvents were saturated with nitrogen. The extinctions obeyed Beer s law for up to 4 to 16 ppm of antioxidant in the HB 307, depending on the compound. Down to 1 ppm of many compounds could be determined, but the applicability of this method is limited by inadequate activation by substituents or by high steric hindrance of the phenolic group. 

Uhde and co-workers [34, 35] have studied the migration of 4,4 -thiobis-6-tert-butyl-w-cresol (Santonex R) from plastics utensils into sunflower seed oil. Sunflower seed oil that had been stored in vessels of polyethylene containing this antioxidant was diluted (3 5) with pentane and extracted with acetonitrile containing 5 % of water. The concentrated acetonitrile extract (or an ethanol solution of the residue on evaporation) was snbjected to thin-layer chromatography on Kieselgel with hexane-ethyl acetate (10 3) as solvent. To detect the antioxidant (down to 0.1 ppm) the plate was sprayed with 3,5-dichloro-p-benzoquinonechlorimine solution. To determine the antioxidant, the zone at Rf = 0.44 (located by means of iodine vapour) was removed and treated with fuming nitric acid sulfuric acid (1 1). The nitro-derivative of the antioxidant was determined in the product by polarography after the addition of urea and sodium acetate [35], 

Alternatively, an aliquot of the original concentrated acetonitrile extract was treated with ethanol and diazotised sulfanilic acid, and the extinction of the resulting dye, measured at 480 nm. This was compared with that for a solution containing 10 pg of antioxidant in acetonitrile, treated similarly. 

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HPLC of polymer extracts has been used to determine dilauryl dithiopropionate, Irganox 1076 and distearyl-dithiopropionate in polyolefins [18], amine antioxidants and antiozonates in rubbers [16], Irganox 1076, Irganox 1010 and BHT in PE [19] and miscellaneous antioxidants, light stabilisers in polyolefins [20,21] and Santonox R, Ethanox 736, CAO-5, Irganox 1035, Irganox 259 and Topanol [22] in polyolefins and also the determination of antioxidants and accelerators in vulcanised rubber formulations [23-25]. 

Figure 5.9 Thin-layer chromatograms of mixtures of antioxidants. Mobile phase benzene - ethyl acetate - acetone (100 5 2). Columns are (a) phenols, (b) amines, (c) hydroquinones, (d) miscellaneous antioxidants, and (e) mixtures of unknown extract formulations Reproduced from Simpson and Currell, RSC [32]...

Uses are estimated to be manufacture of hydrosulfites and other chemicals, 40% pulp and paper, 23% food and agriculture (mainly corn processing), 14% water and waste treatment, 9% metal and ore refining, 6% oil recovery and refining, 4% and miscellaneous, including sulfonation of oils and as a reducing agent or antioxidant, 4% (270,271). 

Miscellaneous Food Additives Directive 95/2/EC (e.g. preservatives, antioxidants, emulsifiers, stabilisers, thickeners, flavour enhancers, acidity regulators, etc.)... 

As required by Directive 89/107/EEC, criteria of purity have been drawn up for all the listed food additives (with a couple of exceptions). Purity criteria for all the permitted sweeteners have been prescribed in Directive 95/31/EC,6 as amended, and criteria for all the permitted colours are contained in Directive 95/ 45/EC,7 as amended. Directives that prescribe purity criteria for all the additives authorised under Directive 95/2/EC have been drawn up in stages. Directive 96/ 77/EC8 containing purity criteria for antioxidants and preservatives is amended by Directives 98/86/EC which lays down purity criteria for emulsifiers, stabilisers and thickeners and 2000/63/EC which contains purity criteria for most additives numbered E 500 and above, and for certain other additives not covered in the earlier directives. Purity criteria for most of the few remaining permitted miscellaneous additives are contained in Directive 2001/30/EC however, purity criteria for E 1201 polyvinylpyrrolidone and E 1202 polyvinylpolypyrrolidone are still being considered by the Scientific Committee on Food. Some methods of analysis for verifying prescribed purity criteria have been developed at EU level these are contained in Directive 81/712/EEC.9... 

Uses. Isoquinoline and isoquinoline derivatives are useful as corrosion inhibitors, antioxidants, pesticides, and catalysts. 1 hcy arc used in plating baths and miscellaneous applications, such as in photography, polymers, and azo dyes. Numerous derivatives have been prepared and evaluated as pharmaceuticals. Isoquinoline is a main component in quinoline still residue bases, which are sold as corrosion inhibitors and acid inhibitors for pickling iron and steel. 

Stage 2 Drop in carbon black, oils, antioxidants, zinc oxide, stearic acid, and miscellaneous pigments such as flame retardants at 160" C. 

Reinforcing fillers used are carbon black and non-black fillers such as silica, clay, and calcium carbonate although the latter two are used more in lower cost industrial applications and not in tires. Protectant systems consist of antioxidants, antiozo-nants, and waxes. The vulcanization system essentially ensures that the optimum mechanical properties of the polymer system are achieved. Finally, the tire compound can contain various miscellaneous materials such as processing aids and resins. The materials scientist when designing a tire compound formulation has a range of objectives and restrictions within which to operate. Product performance objectives define the initial selection of materials. These materials must not raise environmental concerns, be processable in tire production plants, and be cost effective for the end user [4]. 

The annual capacity of DCPD production for all grades in the United States is estimated to be in excess of 350 million pounds in 1999. The major US. producers are B. F. Goodrich Co., Equistar Chemicals (a joint venture of Lyondell Petrochemical, Milennium Chemicals, and Occidental Petroleiun Co.), Exxon Chemical Co., Phillips Petroleum Co., Shell Oil Co., Texmark Chemicals, and Velsicol Chemical Corp. The major consumptions of DCPD in the United States are in the production of hydrocarbon and imsaturated polyester resins (80%), ethylene-propylene terpolymers (10%), reaction injection molding (5%), and miscellaneous uses (5%). The last includes flame retardants, pesticides, antioxidants, and metallocene catalyst production. The demand for DCPD will grow in a rate of 4% per year in the next several years. 

Miscellaneous Fatty extractants (synthetic tryglyceride) Antioxidants, ultraviolet stabilizers, heat stabilizers Using labelled additives [137]... 

Miscellaneous Fatty extractant (synthetic triglycerol-ceride) Phenolic antioxidants Visible spectrophotometric method [168]... 

Antibiotics, 445-480 aminoglycosides, 457-461 cephalosporins, 452-457 macrolides, 463—468 miscellaneous antibiotics, 473-478 poiicillins, 446-452 pqnides, 461-463 tetracyclines, 468-473 Anticircular development of TLC plate, 27 Antioxidants, 803... 

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