Phosphites alkyl

Alkyl Phosphites. The Interaction of Phosphorus Trichloride and Alcohols. 

Oxidation of LLDPE starts at temperatures above 150°C. This reaction produces hydroxyl and carboxyl groups in polymer molecules as well as low molecular weight compounds such as water, aldehydes, ketones, and alcohols. Oxidation reactions can occur during LLDPE pelletization and processing to protect molten resins from oxygen attack during these operations, antioxidants (radical inhibitors) must be used. These antioxidants (qv) are added to LLDPE resins in concentrations of 0.1—0.5 wt %, and maybe naphthyl amines or phenylenediamines, substituted phenols, quinones, and alkyl phosphites (4), although inhibitors based on hindered phenols are preferred. 

Zinc chloride is a Lewis acid catalyst that promotes cellulose esterification. However, because of the large quantities required, this type of catalyst would be uneconomical for commercial use. Other compounds such as titanium alkoxides, eg, tetrabutoxytitanium (80), sulfate salts containing cadmium, aluminum, and ammonium ions (81), sulfamic acid, and ammonium sulfate (82) have been reported as catalysts for cellulose acetate production. In general, they require reaction temperatures above 50°C for complete esterification. Relatively small amounts (<0.5%) of sulfuric acid combined with phosphoric acid (83), sulfonic acids, eg, methanesulfonic, or alkyl phosphites (84) have been reported as good acetylation catalysts, especially at reaction temperatures above 90°C. 

First synthesis of aji organo-P comp iund by J. L. Lassaigne who made alkyl phosphites from H P04 + ROH. T. Graham (who later became the Hrst President of the Chemical Society) classiHed phosphates as ortho, pyro or meta, following J. J. Berzelius s preparation of pyrophosphoric acid by heat. 

Dialkyl phosphates can also be obtained if the ratio of alcohol to PC13 is properly maintained. Halogens will react with alkyl phosphites to give products that have a halogen bound to the phosphorus atom... 

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. 

Phosphites can react not only with hydroperoxides but also with alkoxyl and peroxyl radicals [9,14,17,23,24], which explains their susceptibility to a chain-like autoxidation and, on the other hand, their ability to terminate chains. In neutral solvents, alkyl phosphites can be oxidized by dioxygen in the presence of an initiator (e.g., light) by the chain mechanism. Chains may reach 104 in length. The rate of oxygen consumption is proportional to v 1/2, thus indicating a bimolecular mechanism of chain termination. The scheme of the reaction... 

The situation is different for aryl phosphites, which give rise to shorter chains than alkyl phosphites do (about 100 elementary reactions). The rate of aryl phosphite oxidation, v v suggests that chains are terminated in a linear manner [4,14,27]. Linear chain termination was interpreted in terms of the following mechanism of chain oxidation of aryl phosphites ... 

Reaction of Alkyl Phosphites with a-Halonitroso and a-Halonitro Compounds." Edited by... 

Reaction of a mixed silyl—alkyl phosphite with an aldehyde... 

Arbuzov, A.E. and Dunin, A.A., Action of halogen derivatives of aliphatic esters on alkyl phosphites, /. Russ. Phys. Chem. Soc., 46, 291, 1914. 

Kosolapoff, G.M., Isomerization of alkyl phosphites. VII. Reaction with chlorides of singular structure, /. Am. Chem. Soc., 69, 1002, 1947. 

Hertzog, K., Naumann, P., and Schuelke, U., Combined Production of Substituted w-Alkyl l-a,a-Bisphosphonic Acids and Alkyl Phosphites, East German Patent 222,599, 1985. 

Sifky, M.M. and Osman, F.H., The reaction of alkyl phosphites with 4-triphenylmethyl-l,2-benzoquinone, Tetrahedron, 29, 1725, 1973. 

Alkylperoxy hydridosilane, preparation, 783 Alkyl phosphites, ozone adducts, 732 Alkyl sodium alkyl peroxide,... 

The deterioration resulting from the formation of these free radicals is lessened when antioxidants, such as hindered phenols, alkyl phosphites [(RO),P], or thioesters such as ROOCCH,CH2SCH2CHjCOOR are present ... 

Arylcarbodiimides also dimerize with alkyl phosphites (68CB174) and in special cases with triethylamine (76CC567). HBF4 is effective in giving the corresponding fluoroborate salts which can be converted to the bis(imino)-l,3-diazetidines with base (Scheme 87) (68AG(E)72, 72LA(762)167>. 

Diazothioxanthene is the usual precursor for the thioxanthylidene carbene, which can be shown to have a nucleophilic character. It adds to fumaric or maleic esters to form cyclopropyl compounds, but does not react with cyclohexene (78JOC3303). Reaction with alkyl phosphites is a very useful means of preparing the phosphonate derivatives (72JIC985). 

Alkyl phosphite complexes can be prepared by alcoholysis of chlorophosphine complexes (equation 47).274>332... 

Perchlorofulvalene is a highly reactive chlorocarbon which undergoes a variety of reactions, including dimerization and addition reactions, especially with nucleophiles. It has a unique structure4 which reflects a compromise between steric hindrance and conjugation. The method of preparation exemplifies the use of the mild dehalogenating properties of alkyl phosphites. 

Dickey and Coover (57) showed that alkyl phosphites are capable of initiating polymerization of monomers bearing electron acceptor groups. Polymerization is rapid at moderate temperatures and, in the examples given, the polyacrylonitrile is soluble in acetone. 

Dickey, J. B, and H. W. Coover jr. Polymerization with alkyl phosphite catalysts. United States Patent 2,652,393 (to Eastman Kodak Co.), September 15, 1953. 

The structure of diphosphallenic radical cations, generated from the allene ArP=C=PAr by electrochemical oxidation, has been examined using EPR spectroscopy. Ab initio calculations including correlation effects at the MP2 and MCSCF levels have determined that two rotamers exist compatible with Jahn-Teller distortion of the allene.146 Anodically generated radical cations of alkyl phosphites [(RO P] and silylphosphites [(RO)2POSiMe3] reacted with alkenes by initial attack at the C=C bond followed by electron transfer, deprotonation, and elimination of an alkyl or trimethylsilyl cation to form identical alkyl phosphate adducts.147 The electron ionization-induced McLafferty rearrangement of n-hexylphosphine afford the a-distonic radical cation CTEPH, the distinct reactivity of which suggests there is no... 

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