I. Devedjiev

Reaction Between Oxophosphorus Acids and Glycine

Abstract 2-Hydroxyesters of oxophosphorus acids (hypophosphorous, phosphorous and phosphoric) react with glycine to give amidoglycine-H-phosphinate, cyclic phospho-amidoanhydrideglycine-H-phosphonate and cyclic phosphoamidoanhydrideglycinephosphate. The reaction proceeds easily and in high yields under mild conditions because of the effect of vicinally hydroxy group as intramolecular catalyst on the reactivity of the ester bonds.

Determination of the rate of cure of epoxy resin/maleic anhydride/Lewis acids

Abstract The rates of cure of bisphenol A based epoxy resin and its mixtures with diethylene glycole based epoxy resin with maleic anhydride and accelerator BF 3 etherate were measured from dependences of degree of cure with time. The degree of cure was calculated using the following methods: amount of gel fraction, calorimetry and IR spectroscopy. The activity of the accelerator BF 3 etherate was compared with three Lewis acids: AlCl 3 , TiCl 4 and TlCl 3 . The activity of accelerators was evaluated by the rate of cure and was compared with their molecular characteristics, calculated from molecular structure of the compounds.

Determination of the activity of phosphorus containing compounds on the crosslinking of epoxy resins by acid anhydrides

Abstract The crosslinking of epoxy resin by acid anhydrides was accelerated by several phosphorus containing compounds. The activity of the accelerators was evaluated by the rate of cure W and with activation energy E act . Some of the accelerators were obtained by a new method and were new compounds. The activity of the accelerators was compared with their p K a values. The accelerators decreased the time and the temperature of crosslinking and the effect of chemical structure of acid anhydrides.

REACTION BETWEEN 2-HYDROXY ESTERS OF HYPOPHOSPHOROUS ACID AND ALCOHOLS

Abstract A study of the reaction between esters of hypophosphorous acid and alcohols is carried out. It has been established that the 2-hydroxy esters of hypophosphorous acid react with alcohols as a result of which phosphonous acids are formed. A possible scheme of this reaction is suggested.

ON THE INTERACTION BETWEEN HYPOPHOSPHOROUS ACID AND ALCOHOLS

Abstract The esterification of hypophosphorous acid with alcohols, i.e. isopropanol, isobutanol, n-pentanol, n-octanol and 1,3-propylene glycol leads to the formation of the corresponding phosphonous acid esters in yields of up to 50%, in addition to the hypophosphorous acid esters. The compounds are characterized by their elemental analyses, infrared and 1H NMR spectra. A mechanism of their formation is suggested.

Investigation of solvent interaction in epoxy coatings

Abstract The rate of evaporation of solvents from epoxy coatings was investigated. The coatings were obtained from solutions of epoxy olygomers based on Bisphenol A with molecular weights 600 and 2500. It was established that the rate of evaporation depends on the kind of solvents, molecular weights of olygomers and the possibility of formation of H-bonds. The formation of H-bonds was investigated with UV and IR spectroscopies of the solutions and coatings. From the UV spectra were calculated the shift of the peaks Δν. The ratio A′=A3440/Amax, the shifts Δνv and Δνd and the peak width at half height Δ1/2 were calculated from IR spectra.

METHODS FOR SYNTHESIS OF 1-METHYLOLALLENEPHOSPHONOUS ACID AND ITS HYDROXY ESTERS

Abstract From alkylene oxides and hypophosphorous acid 2-hydroxyesters of the hypophosphorous acid are formed. They undergo an exchange reaction with 2-butyne-1,4-diol as a result of which the corresponding glycol and 1-methylolallenephosphonous acid are obtained. The yield of the acid is quantitative. According to this method also 2-hydroxy esters of 1-methylolallenephosphonous acid are formed.

Phosphorylation of poly(vinyl chloride) and polychloroprene rubber with salts of hypophosphorous acid

Abstract Phosphonous radicals are introduced in poly(vinyl chloride) and polychloroprene rubber by means of an exchange reaction with salts of hypophosphorous acid. The mechanism of the interaction most probably is a variant of the Michaelis-Bekker reaction.

A novel method for the synthesis of acetyl phosphate

A facile method for the synthesis of acetyl phosphate by a reaction of 2-hydroxypropylphosphate with acetic acid is described.

REACTION OF SALTS OF HYPOPHOSPHOROUS ACID WITH ALKYLHALIDES

Abstract Alkali salts of hypophosphorous acid undergo an exchange reaction with alkyl halides. From the interaction between potassium hypophosphite and allyl bromide or 3-chloro-1,2-propanediol phosphonous acids are formed. A mechanism of the interaction, a variant of the Michaelis-Becker reaction, is proposed.