[en] Key results of research into the reactions of cyclophosphorylation of dibasic phenols and related compounds with tri- and pentavalent phosphorus compounds are analysed. Structural features and chemical modification of macrocyclic systems obtained are considered.

No abstract available

[en] Organphosphorus compounds are used in various branches of the chemical industry, but in many cases the reaction mechanisms are not well elucidated and less is known about the intermediates of organophosphines. In order to learn more about these rather complicated processes several organophosphorus compounds were used as model substrates in cyclohexane or benzene solution. The systems have been investigated applying the pulse radiolysis technique and steady-state irradiation methods. As representative solutes were chosen diphenylphosphinous chloride, diphenylmethylphosphine, and triphenylphosphine. By means of the pulse radiolysis it was possible to obtain spectroscopic and kinetic data for characterization of the various transients. The final radiolytic products have been analyzed following steady-state and multipulse radiolysis. Since some of the rate constants were not directly accessible by the applied kinetic method, they have been determined by simulation computation. Thereby the experimental data obtained by pulse radiolysis were used. Based on the kinetic, spectroscopic and computed data as well as on the identification of final products, it was possible to elucidate the reaction mechanism of the diphenylphosphinous chloride/cyclohexane system. As a main primary specie was identified the diphenylphoshorus radical. Its spectral and kinetic data have been determined. The reactions of diphenylmethylphosphine involve the same radical, but only to a lesser extent. The reactions of the primary radiolysis products with triphenylphosphine yield mainly adducts. The results represent a contribution in the field of reaction kinetics of organophosphorus compounds. (author)

[en] Data on biocatalytic methods for the preparation of chiral organophosphorus compounds are generalized and described systematically. Various examples of enzymatic and microbiological synthesis of hydroxyphosphonates, aminophosphonates, phosphinites, phosphine oxides and tertiary phosphines are discussed. The bibliography includes 154 references.

[en] Pakistan being an agricultural country, a large amount of pesticides are used, including organophosphates and synthetic pyrethroids. These pesticides are released through rivers and other tributeries into the coastal environment, thus posing a contiguous threat to marine organisms. In the present study two species of diatoms Amphora and Navicula were selected for the assessment of impact of organ phosphate and pyrethroid toxicity on these primary producers. The study shows that rate of photosynthesis was inhibited in both Amphora and Navicula species exposed to pesticide. The acute toxicity of pesticide was determined by measuring IC50 of the test organisms. IC50 calculated for diatom species depicts that different pesticides had variable effects on the photosynthesis of microalgae. High sensitivity of marine organisms is alarming as it may have implications on the marine ecosystem and fisheries. The results are also useful in setting control limits for the release of these chemicals in nature. (author)

[en] Published data on the synthesis of organophosphorus compounds based on phosphine are fully surveyed, described systematically and analysed for the first time. The bibliography includes 211 references.

[en] Organophosphorus pesticides are environmentally persistent. It is important to find optimum hydrolytic conditions for their degradation in effluents. Kinetic measurements revealed that the values of K/sub obs/ increase w increasing or decreasing the values of pH 3.58 which is the most stable pH condition. Activation volume (delta V) reaction revealed that its values are all negative and are found in the range from -0.031 to -0.045 cm/sup 3//ml. The rate of hydrolysis increases with increasing pH from 3.58, 6.01 and 8.5 by the order of 2.5, 2.75 and 2. respectively for 20 deg. C rise in temperature. Among pH conditions (3.58, 6.01 and 8.5), pH 8.5 is found to be the unstable condition. At pH 8.5, half-life is about 153.31 minutes at 1 atm pressure and is reduced to 38.75 min when the pressure is increased to 10 atm. These results describe that high-pressure thermal hydrolysis is a use technique for the conversion of toxic organic phosphorus into inorganic phosphorus. (author)

[en] The present work summarizes preliminary experiments dealing with the analysis of the main organophosphorus extracting agents TBP, DEHPA and TOPO widely used in hydrometallurgy and particulary in uranium one treatment. In order to ovoid the thermodegraduation processes of such compounds, an adequate combination of vaporization temperature and the carrier gas flow, i,e, the time contact of the compounds in column must be made. In this context, the present work was justly achieved in order to elaborate a only the separation but also the accurate determination of the compounds dealt with. One can remark that maintaining constant the temperature and slightly varying the flow velocity of the carrier gas, the peaks of TBP and butanol were better separated. Nevertheless, a limitation may appear when nitrogen flow is raised up to 30m1/mn. This is essentially due to the lose polarity and their analogous chemical behaviours. Thus one can conclude that such compounds can be easily determined in the ranges of 0-60% for D2EHPA, for TOPO and 24% for TBP. The determination accuracy for all compounds varies between 0.005 and 0.12%. Thus, one can conclude that the organophosphorus extracting agents such as TBP, D2EHPA and TOPO can be easily determined without previous purification. The isothermal conditions are strongly recommemded in this case because of the quickness of the technique. The secondary products resulting from the synthesis process do not affect greatly the determinations of such compounds and their accuracies

[en] Published data on the theoretical conformational analysis of acyclic tri- and tetracoordinate phosphorus compounds by quantum-chemical methods are generalised and systematised. Theoretical results are compared with experimental data for a wide range of such compounds. The main characteristics and fine conformational details of their structures are considered.

[en] 

The review summarizes and systimatizes data on the stereochemistry, mechanisms and applications of electrophilic reactions of organophosphorus compounds. Asymmetric versions of the Michaelis – Arbuzov, Michaelis – Becker, Hirao, Staudinger, Pudovik and other reactions are considered. Key issues of asymmetric electrophilic catalysis are discussed. The reaction conditions, catalytic systems and structures of the reaction products are presented. Asymmetric electrophilic reactions are used in organic synthesis and in studies of the mechanisms of chemical processes involving organophosphorus compounds.

The bibliography includes 209 references. (paper)