Iwona Zarzyka

Esters with imidazo [1,5-c] quinazoline-3,5-dione ring spectral characterization and quantum-mechanical modeling

Abstract1-phenyl-2H,6H-imidazo[1,5-c]quinazoline-3,5-dione reacts with ethyl bromoacetate under mild conditions to give 2-(ethoxycarbonylmethyl)-1-phenyl-6H-imidazo[1,5-c]quinazoline-3,5-dione (MEPIQ) and next 2,6-bis(ethoxycarbonylmethyl)-1-phenylimidazo[1,5-c]quinazoline-3,5-dione (BEPIQ). The products were isolated at high yield and identified on the basis of IR, 1H- and 13C-NMR, UV spectroscopy, and X-ray crystallography. Diester (BEPIQ) can be presented by 16 possible pair of enantiomers. Only one pair of them is the most stable and crystallizes which is shown crystallographic research. Based on quantum-mechanical modeling, with the use of DFT method, which conformers of mono- and diester and why they were formed was explained. It was calculated that 99.93% of the monoester (MEPIQ) is formed at position No. 2 and one pair of the monoester conformers, from six possible, has the largest share (51.63%). These results afforded to limit the number of diester conformers to eight. Unfortunately, the quantum-mechanical calculations performed that their shares are similar. Further quantum-mechanical modeling showed that conformers are able to undergo mutual transformations. As a result only one pair of diester conformers forms crystals. These conformers have substituents in trans position and these substituents are located parallel to imidazoquinazoline ring. This allows for the denser packing of the molecules in the unit cell.

Polyurethane foams obtained from new polyols modified by oxamide and borate groups

New polyols have been obtained in reactions of N,N,N’,N’-tetrakis(2-hydroxyethyl)-derivatives of oxamide, esterified with boric acid (BA), with the excess of ethylene carbonate (EC). The preparation conditions of polyols and next the production of polyurethane foams with the use of these new polyols have been presented. The foaming process parameters as well as the testing of the foam properties have been given. The structure modification of the polyurethane foams by means of oxamide and borate groups resulted in high thermal stability and thermal resistance, dimensional stability, compressive strength as well as the reduced flammability.

Phase diagrams of smart copolymers poly(N-isopropylacrylamide) and poly(sodium acrylate).

The phase behavior of linear poly(N-isopropylacrylamide) (PNIPA), linear copolymer poly(N-isopropylacrylamide) and poly(sodium acrylate) (PNIPA-SA), and chemically cross-linked PNIPA in water has been determined by temperature modulated differential scanning calorimetry (TM-DSC). Experiments related to linear polymers (PNIPA and PNIPA-SA) indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST), which do not correspond to the three classical types of limiting critical behavior. Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water. Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed.

The Modification of Polyurethane Foams Using New Boroorganic Polyols. II. Polyurethane Foams from Boron-Modified Hydroxypropyl Urea Derivatives

The work focuses on research related to determination of application possibility of new, ecofriendly boroorganic polyols in rigid polyurethane foams production. Polyols were obtained from hydroxypropyl urea derivatives esterified with boric acid and propylene carbonate. The influence of esterification type on properties of polyols and next on polyurethane foams properties was determined. Nitrogen and boron impact on the foams’ properties was discussed, for instance on their physical, mechanical and electric properties. Boron presence causes improvement of dimensional stability and thermal stability of polyurethane foams. They can be applied even at a temperature of 150°C. Unfortunately, introducing boron in polyurethanes foams affects deterioration of their water absorption, which increases as compared to the foams do not contain boron. However, presence of both boron and nitrogen determines the decrease of the foams combustibility. Main impact on the decrease combustibility of the obtained foams has nitrogen presence, but in case of proper boron and nitrogen ratio, their synergic activity on the combustibility decrease can be easily seen.

New, thermally stable, rigid polyurethane foams based on polyols obtained using morpholine-2,3-dione derivatives:

In this work, the research results of the synthesis and properties of the polyols with the oxamidoester group, obtained in the reaction of N-substituted morpholine-2,3-dione derivatives with excess of alkylene carbonates have been presented. Using these derivatives as polyol components, rigid foamed polyurethane materials of high thermal stability and mechanical strength have been obtained. New polyurethane foams obtained using hydroxypropyl morpholine-2,3-dione derivatives can be used as heat-insulating materials of operating temperature as high as 150°C.

Effect of the Additive Fire Retardants on the Properties of Rigid Polyurethane Foams, Obtained Using Hydroxyethyl Derivatives of Oxamide and Polymeric 4,4′-diphenylmethane Diisocyanate

The present work investigates the effect of polyol structure and physical addition of boric acid and N,N′-bis(2-hydroxyethyl)oxamide on the properties of rigid polyurethane foams. The product of hydroxyalkylation of oxamide by ethylene carbonate has been used as a polyol component. The new polyol has been foamed using polymeric 4,4′-diphenylmethane diisocyanate, water, and triethylamine. To decrease the flammability of the foams, boric acid, and N,N′-bis(2-hydroxyethyl)oxamide were used as the additive flame retardants. It has been found, that chemical modification of the foam structure by means of oxamide groups decreases their flammability only to a small extent, whereas physical addition of N,N′-bis(2-hydroxyethyl)oxamide does not influence the flammability. However, the addition of boric acid to the foam composition resulted in a distinct decrease of foam flammability, according to the amount of boric acid added. All the foams, modified and nonmodified by boron, have been categorized into flammability class HF-1, according to the applicable standard. The introduction of flame retardants had its impact on the properties of polyurethane foams obtained, as described in this work. GRAPHICAL ABSTRACT

The Modification of Polyurethane Foams Using New Boroorganic Polyols: Obtaining of Polyols with the Use of Hydroxypropyl Urea Derivatives

Methods of synthesis of new prospective polyol components for obtaining of polyurethane foams of reduced combustibility using eco-friendly substrates have been presented. With this end in view, N,N′-bis(2-hydroxypropyl)urea was esterified with boric acid and next the hydrogenborate obtained was hydroxyalkylated by the excess of propylene carbonate. The influence of the way of esterification on the hydroxypropyl derivatives of borate substituted urea properties has been investigated. Esterification was run in the presence and in the absence of solvent. According to instrumental analysis, the characteristic of hydrogenborates obtained in both methods was found to be similar. The hydroxypropyl derivatives of borate substituted urea show similar spectral characteristics and thermal stabilities and differ slightly in molar masses, by-product contents, and physical properties, particularly viscosities. The properties of these derivatives were assessed paying special attention to their application as the polyol components of polyurethane foams. Hydroxypropyl urea derivatives, modified by boric acid, show changes in physical properties with temperature, similarly to typical polyols used for obtaining of polyurethane foams.