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mechanisms of antioxidant action phosphite esters

MECHANiSMS OF ANTIOXIDANT ACTION. PHOSPHITE ESTERS MECHANiSMS OF ANTIOXIDANT ACTION. PHOSPHITE ESTERS K. J. HUMPHRIS and G. SCoTT The University of Aston in Birmingham. Gosta Green, Birmingham. UK ABSTRACT Catechol phosphite esters are powe

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MECHANiSMS OF ANTIOXIDANT ACTION. PHOSPHITE ESTERS

MECHANiSMS OF ANTIOXIDANT ACTION. PHOSPHITE ESTERS K. J. HUMPHRIS and G. SCoTT The University of Aston in Birmingham. Gosta Green, Birmingham. UK ABSTRACT Catechol phosphite esters are powerful stabilizers for polymers and appear to behave differently from simple alkyl or aryl phosphites in that they destroy

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Mechanisms of Antioxidant Action of Phosphite and Phosphonite Esters | SpringerLink

Abstract. Phosphite and phosphonite esters are used on a large scale for the stabilisation of polymers against degradation during processing and long-term applications. They function as antioxidants by various mechanisms depending on their structure, the nature of the substrate to be stabilised and the reaction conditions.

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Mechanisms of antioxidant action. Phosphite esters : Pure and Applied Chemistry

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[PDF] Mechanisms of antioxidant action. Phosphite esters | Semantic Scholar

Catechol phosphite esters are powerful stabilizcrs for polymers and appear to behave differently from simple alkyl or aryl phosphites in that they destroy hydroperoxidcs in a Lewis acid catalysed reaction. The effcctive catalyst is formcd from the starting cster by rcaction with hydropcroxidcs in a series of chemical reactions which during thc initial stages involve the formation of frec radicals.

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Antioxidant action of phosphite, sulfite and borate esters—A comparison - ScienceDirect

Polymer Degradation and Stability 24 (1989) 279-287 Antioxidant Action of Phosphite, Sulfite and Borate Esters A Comparison K. Schwetlick & T. K6nig Sektion Chemie, Techvische Universit~it Dresden, DDR-8027 Dresden, GDR (Received 17 May 1988; accepted 27 May 1988) ABSTRACT The antioxidative activities and mechanisms of action of alkyl and aryl sulfites, borates and boronates have been ...

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Mechanisms of antioxidant action: reactions of phosphites with hydroperoxides - Journal of ...

The decomposition of 1-methyl-1-phenylethyl hydroperoxide by 4-methyl-2,6-di-t-butylphenyl o-phenylene phosphite (Ic) is a catalytic pseudo-first-order reaction which does not appear to involve free radicals.It is preceded by a faster, second-order reaction between the phosphite and hydroperoxide which corresponds to the conversion of the phosphite to the active catalytic species in a reaction ...

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Organophosphorus antioxidants action mechanisms and new trends | Request PDF

Phosphite and phosphonite esters can act as antioxidants by three basic mechanisms depending on their structure, the nature of the substrate to be stabilized and the reaction conditions.

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Antioxidant action of phosphite, sulfite and borate esters—A comparison | Semantic Scholar

Abstract The antioxidative activities and mechanisms of action of alkyl and aryl sulfites, borates and boronates have been elucidated and compared with those of phosphites. Sulfurous and boric acid esters decompose hydroperoxides in a non-radical way, as do phosphites. Sulfites are oxidized to sulfates which readily hydrolyze to give hydrogen sulfates and sulfuric acid which decompose ...

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Chain-breaking antioxidant activity of phosphite esters - ScienceDirect

The sterically hindered aryl phosphites exhibit a similar antioxidative efficiency to 2,6- Chain-breaking antioxidant activity o [phosphite esters 99 G ;5 100 200 300 tl rain Fig. 1. Oxidation of isotactic polypropylene at 180 in the presence of phosphites (0-5 mole/kg). di-t-butyl-4-methyl-phenol (BHT). Noteworthy is the excellent activity of ...

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Mechanisms of antioxidant action: esters of thiodipropionic acid - Chemical Communications ...

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Mechanisms of antioxidant action: esters of ...

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Mechanisms of antioxidant action: reactions of phosphites ...

The decomposition of 1-methyl-1-phenylethyl hydroperoxide by 4-methyl-2,6-di-t-butylphenyl o-phenylene phosphite (Ic) is a catalytic pseudo-first-order reaction which does not appear to involve free radicals. It is preceded by a faster, second-order reaction between the phosphite and hydroperoxide which corresponds to the conversion of the phosphite to the active catalytic species in a ...

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Mechanisms of antioxidant action: Auto-synergistic ...

Mechanisms of antioxidant action 43 R J o k~J ~ ROH 0 HO NO* The formation of both ionic and homolytic products bears a formal resemblance to the phosphite esters which are also stoichiometric reagents for hyd- roperoxides and give rise to both radical and non- radical products [15]. In the latter case, however, pro- oxidant effects are evident ...

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mechanisms of antioxidant action reactions of phosphites ...

Mechanisms of antioxidant action: reactions of phosphites with hydroperoxides Kenneth J. Humphris and Gerald Scott Abstract The decomposition of 1-methyl-1-phen

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Organophosphorus antioxidants action mechanisms and new ...

Phosphite and phosphonite esters can act as antioxidants by three basic mechanisms depending on their structure, the nature of the substrate to be stabilized and the reaction conditions. All phosph(on)ites are hydroperoxide‐decomposing secondary antioxidants.

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Mechanisms of antioxidant action: products of the reaction ...

4-Methyl-2,6-di-t-butylphenyl o-phenylene phosphite (Ic) reacts with 1-methyl-1-phenylethyl hydroperoxide to give phenol, acetone, and α-methylstyrene as major products with acetophenone and 1-methyl-1-phenylethyl alcohol as minor products.At high ratios of hydroperoxide to phosphite, the former products which are formed by an acid catalysed reaction predominate, although a substantial ...

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Chain-breaking antioxidant activity of phosphite esters ...

Chain-breaking antioxidant actit, ity o[phosphite esters 103 TABLE 1 Rate Constants of Reactions of Phosphites with ROO' Radicals and Stoichiometric Factors of Phosphites in the AIBN-initiated Oxidation of Cumene in Chlorozene at 65 , ri = 2.4 x 10- 6M s- 1, [RH] = 1.7M, k3 = 1-5M- 1 s- 1 (Ref. 6) Phosphite F" K7 (M - 1 s- 1 ) le 0.6 80 If 0.6 ...

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phosphite thioester antioxidant auxiliary antioxidant

MECHANiSMS OF ANTIOXIDANT ACTION. PHOSPHITE ESTERS. The antioxidant is a powerful Lewis acid as is shown by the decomposition products formed from cumene hydroperoxide by both the catechol hindered-phenyl phosphite and phosphate (Figure 13).

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Mechanisms of Polymer Degradation and Stabilisation ...

Mechanisms of Antioxidant Action of Phosphite and Phosphonite Esters. Klaus Schwetlick. Pages 23-60. Antioxidant Mechanisms of Derivatives of Dithiophosphoric Acid. ... In Chapter 2, Schwetlick reviews the current state of knowledge on the antioxidant mechanisms of the phosphite esters with particular emphasis on their catalytic peroxidolytic ...

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Action Mechanisms of Phosphite and Phosphonite Stabilizers ...

Advances in Chemistry All Publications/Website. OR SEARCH CITATIONS

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Mechanisms of antioxidant action: esters of ...

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Organophosphorus antioxidants action mechanisms and new ...

Phosphite and phosphonite esters can act as antioxidants by three basic mechanisms depending on their structure, the nature of the substrate to be stabilized and the reaction conditions. All phosph(on)ites are hydroperoxide‐decomposing secondary antioxidants.

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mechanisms of antioxidant action reactions of phosphites ...

Mechanisms of antioxidant action: reactions of phosphites with hydroperoxides Kenneth J. Humphris and Gerald Scott Abstract The decomposition of 1-methyl-1-phen

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Mechanisms of antioxidant action: products of the reaction ...

4-Methyl-2,6-di-t-butylphenyl o-phenylene phosphite (Ic) reacts with 1-methyl-1-phenylethyl hydroperoxide to give phenol, acetone, and α-methylstyrene as major products with acetophenone and 1-methyl-1-phenylethyl alcohol as minor products.At high ratios of hydroperoxide to phosphite, the former products which are formed by an acid catalysed reaction predominate, although a substantial ...

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Antioxidation and mechanism of phosphites including the ...

The mixture of antioxidants thus generated is responsible for the high stabilizing efficiency of phosphite and phosphonite esters in autoxidations at these temperatures.In addition to hydrolysis ...

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Mechanisms of antioxidant action: the pro-oxidant stage in ...

The thermal decomposition of dimethyl sulphinyldipropionate alone and in the presence of 2,6-di-t-butyl-α-(3,5-di-t-butyl-4-oxo-2,5-cyclohexadiene-1-ylidene)-tolyloxy (Galvinoxyl) was studied. Results show that radical intermediates capable of initiating oxidations are not produced under these conditions but radica

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Mechanisms of antioxidant action of organic phosphorus ...

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Action Mechanisms of Phosphite and Phosphonite Stabilizers ...

Advances in Chemistry All Publications/Website. OR SEARCH CITATIONS

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triphenyl phosphite antioxidants triphenyl phosphite ...

MECHANiSMS OF ANTIOXIDANT ACTION. PHOSPHITE ESTERS. the hindered phenyl phosphite II, R 2,4,6-tri-tert-butyiphenyl was the most effective structure examined and that antioxidant effectiveness paralleled reactivity toward the 'stable' free radical diphenylpicryl hydrazyl.

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An investigation of the versatile antioxidant mechanisms ...

An investigation of the versatile antioxidant mechanisms of action of rosmarinate alkyl esters in oil-in-water emulsions J Agric Food Chem . 2012 Mar 14;60(10):2692-700. doi: 10.1021/jf204848b.

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