Reactions taking place in the systemN,N,N′,N′,N″- pentakis(hydroxymethyl)melamine-oxirane in aqueous media

Lubczak, Jacek; Myśliwiec, Bogdan; Bukowski, Wiktor

doi:10.1002/(sici)1097-4628(20000509)76:6<824::aid-app8>3.0.co;2-1

Cited by 6 publications

(5 citation statements)

References 3 publications

(1 reference statement)

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“…The gas chromatographic studies were done with Hewlett‐Packard, type 5890 with FID, while the identification of side products were performed using: capillary HP‐FFAP column of 10 m length and 0.53 mm diameter; 0.1 μm thickness; within the 50–220°C temperature range and 20°/min gradient, followed by 5 min heating at 240°C temperature; injector and detector temperature 220°C; 18.3 cm 3 /min helium flow rate; sample volume 0.2 μdm 3. The calibration curves were used as before 6, 7. MALDI ToF (Matrix‐Assisted Laser Desorption Ionization Time of Flight) were obtained on Voyager‐Elite Perseptive Biosystems (USA) mass spectrometer working at linear mode with delayed ion extraction, equipped with nitrogen laser working at 337 nm.…”

Section: Methodsmentioning

confidence: 99%

Hydroxyalkylation of barbituric acid. II. Synthesis of polyetherols with pyrimidine ring

Slaczka

Lubczak

2007

J of Applied Polymer Sci

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The route of synthesis of new polyetherols with pyrimidine ring from barbituric acid (BA) was presented. The polyetherols were obtained in two steps: synthesis of hydroxymethyl derivative of BA followed by reaction of the latter with neat ethylene or propylene oxides. Physical properties of the products and preliminary application for fabrication of thermal stability polyurethane foams were determined.

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Section: Methodsmentioning

confidence: 99%

Hydroxyalkylation of barbituric acid. II. Synthesis of polyetherols with pyrimidine ring

Slaczka

Lubczak

2007

J of Applied Polymer Sci

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“…Calibration curves were used as described in the literature. [12][13][14] The IR spectra were recorded on a Specord 71 IR (Zeiss, capillary film). 1 H-NMR spectra were recorded on an 80-MHz Tesla BS 487C spectrometer (Czechoslovakia) in a DMSO-d 6 solution with HMDS as the internal standard.…”

Section: Methodsmentioning

confidence: 99%

“…To identify all the peaks in the chromatograms due to the products of oxirane with water, chromatograms were analyzed using data in the literature. [12][13][14] The chromatograms contain mainly peaks corresponding to respective glycols and a few subsequent products of addition of oxiranes to these glycols (Table IV). The amount of glycols and their subsequent products was found in the polyethers to be relatively small.…”

Section: Analysis Of Side Productsmentioning

confidence: 99%

Reactions of hydroxymethyl derivatives of uric acid with oxiranes. I. Synthesis of polyetherols with purine rings

Cisek-Cicirko

Lubczak

2000

J. Appl. Polym. Sci.

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“…These compounds can self‐condense and react with compounds containing hydroxyl, amido, or carboxyl groups. The reaction between the melamine compounds and oxiranes, such as propylene oxide and ethylene oxide, result in the formation of polyetherols, which are used in polyurethane foams 6–8. Generally, during the preparation of linear polyetherols, a large excess of oxirane is introduced into the reaction compositions to prevent undesired melamine condensation 8.…”

Section: Introductionmentioning

confidence: 99%

Modelling crystal growth between potash particles near contact points during drying processes. Part II: Analysis, results, and comparison with experimental data

2008

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Caking of bulk granular materials is a serious problem that affects many industries including the mineral processing industry. Caking occurs when bulk materials undergo wetting and drying cycles and it has been thought that it occurs due to the formation of new crystal bridges between individual particles. In the first paper in this series a mathematical model is developed for the crystal formation process that occurs at the contact point between two particles. In Part II, numerical simulations of the model are used to determine the effects of changes for several independent parameters in this model: initial moisture content; rate of evaporation of the salt solution from the particle surface; relative size of the contact region compared to the initial film thickness of salt solution; and supersaturation levels near the contact point. Non-dimensional graphical curves of these simulations are used to compare the effects of each parameter for the deposition of salt crystals near the contact point. These results, when compared to data for cake strength in potash specimens which were obtained for various initial moisture contents, drying rate, and chemical composition of the particle surfaces, show good qualitative agreement even though cake strength and mass recrystallization near a contact point are different physical phenomena. The numerical results show that the mass of crystal deposition near the contact point will increase with increased initial moisture content and decreased evaporation rate. It is also found that variations in the degree of supersaturation near the contact point causes significant variations in the crystal mass deposition near the contact point. L'agglomération de matériaux granulaires en vrac est un problème important qui perturbe beaucoup d'industries, comme l'industrie des traitements des minéraux. L'agglomération survient lorsque les matériaux en vrac subissent des cycles d'humidification et de séchage, un phénomène que l'on croit causé par la formation de nouveaux ponts de cristaux entre les différentes particules. Dans le premier article de cette série, un modèle mathématique est mis au point pour le procédé de formation des cristaux survenant au point de contact entre deux particules. Dans la deuxième partie, on utilise des simulations numériques du modèle afin de déterminer les effets des changements pour plusieurs paramètres indépendants dans ce modèle,à savoir: la teneur en humidité initiale, la vitesse d'évaporation de la solution salineà la surface des particules, la taille relative de la région de contact par rapportà l'épaisseur de film initiale de la solution saline et les niveaux de sursaturation près du point de contact. Des courbes adimensionnelles de ces simulations sont utilisées pour comparer les effets de chaque paramètre sur le dépôt des cristaux de sel près du point de contact. Lorsqu'on les compare aux données sur la force du gâteau dans les spécimens de potasse obtenus pour différentes teneurs en humidité initiales, la vitesse de séchage et la composition chimique des...

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Reactions taking place in the systemN,N,N′,N′,N″- pentakis(hydroxymethyl)melamine-oxirane in aqueous media

Cited by 6 publications

References 3 publications

Hydroxyalkylation of barbituric acid. II. Synthesis of polyetherols with pyrimidine ring

Hydroxyalkylation of barbituric acid. II. Synthesis of polyetherols with pyrimidine ring

Reactions of hydroxymethyl derivatives of uric acid with oxiranes. I. Synthesis of polyetherols with purine rings

Modelling crystal growth between potash particles near contact points during drying processes. Part II: Analysis, results, and comparison with experimental data

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