Organophosphorus antioxidants

K. Schwetlick and W.D. Habicher, Organophosphorus antioxidants action mechanisms and new trends, Angewandte Makromolekulare Chemie, 232(l) 1522-9505, January 1995. 

In spite of their toxicity, alkyl phosphites have been used extensively as lubricant additives, corrosion inhibitors, and antioxidants. In addition to their use as intermediates in synthesis, organophosphorus compounds are useful for separating heavy metals by solvent extraction. Several insecticides that were formerly in widespread use are derivatives of organic phosphates. Two such compounds are malathion and parathion. 

Phenol and substituted phenol compounds (Fig. 19) are known to be widespread as components of industrial wastes. These compounds are made worldwide in the course of many industrial processes, as for example in the manufacture of plastics, dyes, drugs, and antioxidants, and in the pulp and paper industry. Organophosphorus and chlorinated phenoxyacids also yield chlorinated and nitrophenols as major degradation products. 4-Nitrophenol was reported as a breakdown product after the hydrolysis and photolysis of Parathion in water and chlorinated phenols are formed by the hydrolysis and photolysis of chlorinated phenoxyacid herbicides [251-253]. 

Organophosphorus compounds are also becoming essential as antioxidants of petroleum lubricant oils, as synthetic lubricants and plastifiers for various polymers. Organophosphorus compounds are widely used to obtain substances which do not sustain combustion, because they are highly efficient fire retardants. 

Datta, C., Gupta. J.. Sarkar. A., and Sengupta. D. (1992), Effects of organophosphorus insecticide phosphomidon on antioxidant defence components of human erythrocyte and plasma. Indian J Exp. Biol. 30,65-67. 

Uses Synthesis of organophosphorus compels, for EP lubricants, adhesives catalyst in polymerization of unsaturated compds. stabilizer lubricant additive antioxidant for plastics antioxidant and EP agent in lubricants textile finishing agents pesticides Manuf./Distrib. ABCR http //www.abcr.de, Acros Org. http //www.acros.be-, GE Spec. http //www.ge.com/specianychemicals-, ICN Biomed. Research Prods. http //www.icnbiomed.com-, Kowa Am. http //www.kowa.com/chemicai/... 

Uses Synthesis of organophosphorus compds. color stabilizer for unsat. polyesters, polyolefins sec. stabilizer for PVC antioxidant forPP... 

Since pyrethrins are highly photolytic, antioxidants are often added to preparations to stabilize formulations antioxidants adjoin include pyrocatechol, pyrogal-lol, hydroquinone, and l-benzene-azo-2-naphthol. Practically, all pyrethrins and many pyrethroids are commonly combined to additives (including synergists), some formulations include additional insecticides, insect repellents, or both, and many contain hydrocarbon solvents [3] to enhance their insecticidal activity. Pyrethrin and pyrethroid sprays may also be water based or be alcohol or petroleum based, which increases the overall toxicity. It is known that concomitant use of pyrethrins and pyrethroids with synergists such as piperonyl butoxide, A -octyl bicycloheptene dicarboximide, sulfoxide, sesamin, sesame oil, sesamolin, isosafrole, and organophosphorus compounds or carbamates may increase toxicity by mechanisms involving inhibition of microsomal oxidation [4]. 

Phenolic compounds are ubiquitous in the environment coming from different sources such as manufacturing processes used in the plastic, dye, drug, antioxidant, and pesticide industries. Chloro- and nitrophenols are the main degradation products of many chlorinated phenoxy acid and organophosphorus pesticides, respectively [1,2]. These compounds are of particular interest and concern to the environment because they are toxic to most aquatic organisms [3,4]. Moreover, they affect the taste and odor of both water and fish even at very low concentrations of phenolic compoimds in water [5]. The US Environmental Protection Agency (EPA) has listed 11 phenols as priority pollutants [6]. 

Methods 17 and 18, respectively, determine Cyasorb UV 531 (2-hydroxy-4-n-octoxybenzophenone) in polyolefins by direct infrared spectroscopy and thin-layer chromatography. Phenolic and organophosphorus type antioxidants do not interfere in these procedures. Method 19 describes an ultraviolet spectroscopic method for the determination of Tinuvin 326 ultraviolet absorber in polypropylene. 

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