V. P. Lodygina

The Formation of the Polyisocyanurate Networks Structure

Abstract The reactions of PCT and CPCT of aliphatic isocyanates in the presence of catalysts HBSO and CN-DMSO were found to obey the first-order law. The observed rate constants at various temperatures and catalyst concentrations, the activation energy were determined. It was shown that in the PCT process with above catalysts practically only one type of a cyclic structure (isocyanurate) was formed. The HMDI PCT gives a highly cross-links polymer, the cross-links density of a network being equal to v = 26 × 10−4 mol/cm3. In CPCT the polyisocyanurates with various cross-links density of a polymer network were obtained. At different ratios of mono- and diisocyanate the molecular-mass parameters of the interunit chains were determined, their effect on physico-mechanical properties of polyisocyanurates was established.

Kinetics of diisocyanate reactions with chain-extending agents

The kinetics of polyurethane formation reactions was studied using the interaction of hexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and tolylene 2,4-diisocyanate with the chain-extending-agents 1,3-and 1,4-butanediol as an example. For pair interactions of functional groups of diols with diisocyanates, rate constants were calculated. The effect of the nature of diisocyanates and the structure of diols on the kinetics of the reactions under consideration was examined. It was shown that, at the final stage of polyurethane formation, the reactivities of aromatic tolylene 2,4-diisocyanate and aliphatic hexamethylene diisocyanate level off. The influence of dibutyltin dilaurate as a catalyst on the reactivity of functional groups was assessed. It was established that the reactivities of functional groups of asymmetric molecules level off in the presence of the catalyst. It was demonstrated that the structure of diols affects the thermal behavior of polyurethane block copolymers.

Synthesis of 5-dinitromethyltetrazole

A convenient method of synthesizing 5-dinitromethyltetrazole on the basis of 1,1-diamino-2,2-dinitroehtilene was developed.

Reactions of 1,1-diamino-2,2-dinitroethylene with diamines

Reactions of 1,1-diamino-2,2-dinitroethylene with diamines were studied.

Specific features of urethane-formation reactions in azide-containing media

The kinetic features of reactions of 1,6-hexamethylene diisocyanate with azide-containing oligodiols of the polyether nature and low-molecular-mass alcohols and diols containing primary and secondary OH groups in the presence of small amounts of cyclic azide-containing monomers have been studied. As evidenced by IR measurements, hydroxyl groups occur in the systems under study in the form of various associates involving system components. The activation effect of azide groups on the kinetics of urethane-formation has been established, and a feasible mechanism of this activation that relies on ideas concerning the role of associative interactions in the reaction system has been advanced.

Cubane derivatives: 8. Synthesis of nitroxyalkyl-substituted cubane-1,4-dicarboxamides and 4-bromocubanecarboxamides

New substituted cubane-1,4-dicarboxamides and 4-bromocubanecarboxamides containing the nitroxyl group and amino acid fragments along with the cubane skeleton were synthesized. The cardiac pharmacological activity (both the effect on aorta relaxation and the calcium channel blocking activity) of most of nitroxyalkyl derivatives is equal to or higher than that of N-(2-nitroxyethyl)nicotinamide (nicorandil).

CUBANE DERIVATIVES. 3. SYNTHESIS AND ANTIISCHEMIC ACTIVITY OF SOME NITROXYALKYL DERIVATIVES OF 1,4-CUBANEDICARBOXYLIC ACID AND ITS DIAMIDE

NewN,N′-bis- andN,N,N′, N′-tetrakis-hydroxyalkyl-substituted 1,4-cubanedicarboxamides were synthesized. Nitration of these compounds yielded the corresponding nitrates. The reaction of 1,4-cubanedicarboxylic acid dichloride with ethylene glycol mononitrate and glycerol dinitrate gave ester 1,4-[R1R2CHOC(O)]2C8H6, where R1=H and R2=CH2ONO2; and R1=R2=CH2ONO2, respectively. The cardiopharmacological activity of some of the synthesized compounds was determined. This allowed us to find for the first time cubane derivatives that exhibit this kind of biological activity. The antiischemic activity of one of these compounds,N,N′-bis(2-nitroxythyl)-1,4-cubanedicarboxdiamide, is higher than that of the well-known Nicorandil.

Kinetics of urethane formation from isophorone diisocyanate: The alcohol nature effect

The kinetics of the noncatalytic reactions of isophorone diisocyanate with n-propanol, isopropanol, 1,3-diazidopropan-2-ol, propargyl alcohol, and phenol in toluene in the temperature range from 20 to 90°C at the stoichiometric ratio of reactive groups has been investigated by IR spectroscopy. The apparent rate constants for the reactions of the aliphatic and cycloaliphatic isocyanate groups of isophorone diisocyanate with all of the alcohols have been measured. The activation parameters of the reactions of isophorone diisocyanate with n-propanol, isopropanol, and 1,3-diazidopropan-2-ol have been determined. The data obtained are considered in terms of the alcohol structure and molecular organization of solutions.

Kinetics of urethane formation from isophorone diisocyanate: The catalyst and solvent effects

The dependence of the kinetic parameters of urethane formation in the reaction between isophorone diisocyanate and alcohols of different structure (n-propanol, isopropanol, propargyl alcohol, 1,3-diazidopropan-2-ol, and phenol) in diluted solutions on the natures of solvent (toluene, carbon tetrachloride) and catalyst (dibutyltin dilaurate, diazobicyclooctane) was found using an original IR spectroscopic procedure. The ratio of the apparent rate constants for the reactions involving the aliphatic and cycloaliphatic NCO groups of isophorone diisocyanate was determined, and the efficiency of catalysis in these reactions was estimated. The reaction conditions under which the difference between the reactivities of isocyanate groups can reach 40 were determined.

Synthesis and study of organic nitrates of heterofunctional series. 5. Synthesis of 3,3-bis(hydroxymethyl)oxetane mono- and dinitrates and 2,2-bis(hydroxymethyl)propane-1,3-diol (pentaerythritol) mono- and dinitrates

New procedures were developed for the synthesis of 3,3-bis(hydroxymethyl)oxetane dinitrate (1) by O-nitration of the corresponding glycol (3) or its mononitrate (6), which were prepared by the reactions of 2,2-bis(hydroxymethyl)propane-1,3-diol (pentaerythritol) (2) mono- (4) and dinitrates (5), respectively, with alkali. A new method was devised for the synthesis of compounds 4 and 5 by the reaction of tetraol 2 with concentrated HNO3 in dichloroethane. The structures of compounds 1 and 6 were established by X-ray diffraction analysis.