Reactions in the presence of organic phosphites,I: High temperature amidation in the absence of solvents

When reacted for periods of 5–10 min at temperatures of about 280–300°C in the presence of certain organic phosphites polymers that contain available carboxy and aliphatic amine groups undergo amidation. This reaction can increase the molecular weight of many aliphatic polyamides by their self-reaction in an extruder. Block or graft copolymers can be formed by reacting polymers that contain aliphatic amines with others that contain carboxyl. Studies of model compounds in the companion article (II) indicate that polymerization proceeds through an diaryloxy or dialkoxy amino phosphine intermediate to produce amide bonds and disubstituted phosphite reaction by-products. In the absence of primary amines in the reaction mixture an ester is slowly formed from the carboxyl end group of the polymer and the oxysubstituent of the phosphite. In no case was a phosphorus-containing mixed anhydride detected. The mechanistic identity of the low temperature reactions in article II and the high temperature reactions in this article has not been proved conclusively, however.     

Reactions of some organic peroxides with triphenylphosphine and sodium dialkyl phosphites

The reactions of the allylic peroxides ascaridole, cyclohexadiene endoperoxide, and α-phellandrene peroxide with triphenylphosphine follow an S_N ^i'-type mechanism. In contrast, the acyclic allylic compounds, allyl tert-butyl peroxide, α-cumyl cyclohexenyl peroxide, and tert-butyl cyclohexenyl peroxide apparently react with triphenylphosphine by a free-radical mechanism. The saturated cyclic peroxide dihydroascaridole, in which there is no possibility of an allylic rearrangement, gives with triphenylphosphine a mixture of olefinic alcohols. Di-n-butyl peroxide is readily cleaved by sodium dialkyl phosphites, but sterically hindered peroxides do not react under similar conditions. Reaction can, however, take place at the oxygen adjacent to a large group if a smaller substituent is present on the other oxygen atom.     

Reactions of some nitrosoperfluoroalkanes with trimethylsilyl phosphites

Nitrosotrifluoromethane or nitrosopentafluoroethane reacted with trimethylsilyl diethyl or tris(trimethylsilyl) phosphite to give phosphato-fluorocarbimino- or phosphato-trifluoroacetimino-phosphonates and fluorotrimethylsilane. Some intermediate compounds could be detected by NMR spectroscopy, namely, diethyl (N-trimethylsiloxy-N-trifluoromethyl)- or diethyl (N-trimethylsiloxy-N-pentafluoroethyl)amidophosphate and difluorocarbimino diethyl phosphate. © 1996 John Wiley & Sons, Inc.     

Radical addition of dialkyl phosphites: Application in organic synthesis

Synthesis and application of phosphorylated esters, alcohols, ketones, epoxides, carbamates and carbamides, amino acids, and pyrimidines is reviewed.     

Photopolymerization of acrylonitrile in the presence of substituted triphenyl phosphites

It was found that acrylonitrile was polymerized at 30°C by ultraviolet irradiation in the presence of triphenyl phosphite and its derivatives, namely m-CH₃, p-C₂H₅, and p-CH₃ substituted triphenyl phosphites under conditions where acrylonitrile alone did not polymerize and phosphites did not undergo photolysis. The rate of polymerization in the presence of triphenyl phosphite and tri-p-tolyl phosphite was found to be proportional to the monomer concentration, the phosphite concentration, and the light intensity. From these results, it was thought that a donor–acceptor complex formed between phosphite and acrylonitrile which absorbed light and initiated the radical polymerization. In the photopolymerization of acrylonitrile with substituted triphenyl phosphites, the rate of polymerization increased with an increase in electron-donating ability of substituent. From the plot obtained by use of Hammett's equation (log R_p/R_p0 = ρσ), the ρ value was found to be ?1.0.     

Reactions of dialkyl hydrogen phosphites with phosphorous amides

Russian Chemical Bulletin -     

Reactions of thiols and organic sulfides with hydrogen in the presence of iron powder

Previously unknown reduction of thiols to hydrocarbons and H₂S with hydrogen formed by the interaction of powdered iron with dilute HCl was found. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1380–1382, August, 2006.     

Reactions of 2-pyrimidinyl phosphites with proton-containing nucleophilic reagents

Conclusions The reaction of 4,6-dimethyl-2-pyrimidinyl phosphites with proton-containing nucieophilic reagents is due to the anhydride nature of the C_pry-O-P bond and proceeds with the formation of 4,6-dimethyl-1,2-dihydro-2-pyrimidone and the corresponding P(III) derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 159–162, January, 1986.     

Thermal properties of post-consumer PET processed in presence of phosphites

Thermal properties of recycled triphenylphosphite (TPP) chain extended poly(ethylene terephthalate) (PET) was investigated. As the TPP concentration increases, both reaction residues and molecular mass increase affecting significantly the thermal properties and crystallization behavior of the material. The presence of TPP residues did not affect the crystalline melt temperature (T _m), but modified the glass transition temperature (T _g), the crystallization temperature on heating (T _hc) and the crystallization temperature on cooling (T _cc). In the samples submitted to extraction with acetone, the properties were influenced by molecular mass changes, probably due to the presence of some insoluble reaction residue. The thermal stability of the sample purified by extraction after chain extension was comparable to that of the non-extended sample when heating was carried out under nitrogen atmosphere.This revised version was published online in November 2005 with corrections to the Cover Date.     

Low-temperature polyesterification in the presence of tertiary amines

Several variations of catalysis (nucleophilic and general basic) responsible for the lowtemperature polyesterification in solution have been investigated. The type of catalysis which predominates depends on the chemical structure of the initial reagents and the reaction conditions. Increasing basicity of the tertiary amine and increasing acidity of the bisphenol promote the general base catalysis.     

Reactions of 1,2,2,2-tetrachloroethyl isocyanate with trialkyl and trimethylsilyl phosphites

The reaction of 1,2,2,2-tetrachloroethyl isocyanate with trialkyl phosphites is unselective. It involves chlorine substitution, addition by the isocyanate group, and dehydrochlorination and gives rise to a mixture of mono- and diphosphorylated compounds. Diethyl trimethylsilyl phosphite more selectively reacts with 1,2,2,2-tetrachloroethyl isocyanate. At a 1:1 molar reagent ratio, an -phosphorylated trichloroethyl isocyanate is formed, and at a 2 : 1 ratio, chlorine substitution and addition by the isocyanate group take place to give a related 1,3-diphosphonate.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1456–1459.Original Russian Text Copyright © 2004 by Onysko, Maidanovich, Sinitsa.This revised version was published online in April 2005 with a corrected cover date.     

Reactions in aminosilane-epoxy prepolymer systems. II. Reactions of alkoxysilane groups with or without the presence of water

The hydrolysis and reactions of alkoxy silane groups have been studied on a model compound (TA) prepared from 2 mol of phenyl glycidyl ether and 1 mol of aminopropyl triethoxy silane. At low (40°C) and high (140°C) temperatures, the monomer conversion and the evolution of the molecular mass are followed by size exclusion chromatography (SEC). During the same reaction time, the evolution of the functional groups, hydroxyl CH? OH, ethoxy ? O? C₂H₅, and siloxane Si? O? Si, is observed by FTIR spectroscopy. Without the presence of water, reactions between hydroxyl and ethoxy silane lead to gelation at the end of the reaction. A by-product, probably a cyclic tetramer is also formed. After the hydrolysis, the reaction of the model compound is quite different. The product of reaction is always soluble, even after a treatment at high temperatures, and the evolution of the molecular mass versus the reaction time seems to correspond to the condensation giving a dead cyclic tetramer. From this study it is evident that the curing cycle has a great influence on the properties of the interface of a composite based on a epoxy matrix.     

The palladium-catalysed reaction of butadiene with acetic acid in the presence of phosphites

The palladium-catalysed co-oligomerisation of butadiene with acetic acid in the presence of various phosphites has been studied. It has been found that the use of ortho-alkyl or ortho-aryl substituted triaryl phosphites as ligands enables almost quantitative yields of acetoxyoctadienes to be obtained. Furthermore a significant degree of control of isomer ratios can be achieved.     

Metal complexes with ligand-organic phosphites as polyolefin antioxidants. II. Kinetics and mechanism of synergism at oxidation inhibition by metal acetylacetonates and organic phosphites

The widely known synergism of oxidation inhibitors with metals of transient valency is shown in the new process with organic phosphite participation. The effects of inadditive strengthening phosphite action by acetylacetonates of transient metals (Me) have been investigated in different oxidation systems (solid polymer, melt, and liquid phase). The kinetic interpretation of effects, their quantitative analysis, and mathematical modeling are given, and the general regularities governing the efficiency of Me + organic phosphite compositions in any oxidation mode in the presence of initiator and at polymer autoxidation are revealed.