Adilov R.I, Eshchanova G.E, Hudoyorova.D.B.
Tashkent Chemical-Technological Institute, Uzbekistan
Закономерности формирования мономером и олигомер продукты взаимодействия моноэтаноламина и альдегидов
Мономер ва олигомер маҳсулотларининг моноэтаноламин ва алдегидлар билан ўзаро таъсирланиш қонуниятларининг шакллари
The research of the last years showed that perspectivity of the usage haloid – hydrooxylcontaining ammonium compounds like antrinirenes. The aim of the work is the creation of homological raw of hydrooxylcontaining oligomers.
In the interaction of aldehydes with amines in the dependence on the nature of initial substances and conditions of conducting reactions can be formed various, nitrogen-containing products . Among these products insufficiently explored are functionalized azomethines, in particular, hydroxyl-containing azomethines, which can find a wide usage as catalysts-crosslinking agents in the production of usual and frothed polyurethanes . In this aspect a great interest present products in the interaction of monoethanolamine with aldehydes due to the usage of aldehydes of various nature the possibility of variation structure and properties of synthesized hydroxyl-containing azomethines are appeared .According to the mentioned above, in this work the results of studies on the synthesis of monomer and oligomer hydroxyl-containing compounds of various nature and the study of their physical and chemical properties are presented. As an experimental part, we can suggest that for the synthesis of hydroxyl-containing compounds monoethanolamine on TU6-02-915-74 was used, the first sort, the content of the basic substance is at least 99%. Monoethanolamine was purified by vacuum distillation at 343k|1.6k Pa. The purified product had n20d=1.4539. Characteristics of used aldehydes are shown in table I.
Main physical and chemical properties of the used aldehydes
Basic substance,% N.
|Temperatu re C
|20.2||64.4||90-95 / 3.9-7.9 kPa||52-54 (mp)||73.8 / 2.7 kPa|
|Density kg / m3||1092||7830||7904||1598||1045|
Hydroxyl-containing compounds were synthesized on the method of described in . Reaction was conducted in the mass at the equivalent ratio of aldehyde: monoethanolamine. In the intensive mixing of monoethanolamine was heeled-in aldehyde. In the case of furilacrolein heeling-in monoethanolamine the temperature of reaction mass was maintained at 60+20C. Final products were subjected to vacuum distillation at the residual pressure 10 mm. Hg.tor. Oligomers were received by the way of thermal treatment of monomer azomethines in the neckled flask, equipped with oil seal, stirrer, capillary for passing nitrogen, trap Dina-Stark. The temperature and duration were varied. Control on the reaction was conducted on the change of content hydroxyl groups, tertiary nitrogen, viscosity, molecular weight and on the quantity of generated water (if necessary), and also on the change intensities of absorption bands of functional groups on IR spectra. IR spectra was taken on the unit UR-20 in a cell thickness of 0,4mm. The viscosities of oligomers were determined on reaviscosimetre Hoppler.Aminoalcohols belong to heterofunctional compounds that exhibit chemical properties and amines and alcohols. In this case, the mutual influence of functional group leads to the appearance by them a number of features. In particular, due to the electron-acceptor character of hydroxyl groups basicity of aminoalcohols and nucleophilicity of nitrogen atom in them are lower than in analogous aliphatic amines. In its turn, nucleophilicity of oxygen hydroxyl group atom is also reduced due to the negative inductive effect of amino group. Foregoing causes the moderate reaction activity of functional group of amino alcohols in the reactions, typical for them, particularly, in the reactions of nucleophilic compounds.
Aldehydes are one of the representatives of carbonylcontaining compounds. In carbonyl group π-electrons of double bond are strongly drown to oxygen. Therefore, carbon of carbonyl group becomes the electronodeficient centre, and oxygen becomes electron-excess. As a result, in the carbon atom of carbonyl group occurs a partial positive charge (δ +) and in the oxygen atom occurs partical negative charge (δ -) . All these lead to the fact that carbon atom becomes the centre for nucleophilic attack, oxygen atom with lone pairs of electrons – the main centre, on which the acid catalysis in reaction compounds are used.Thus, the more partial positive charge is in the carbon of carbonyl group, the easier the nucleophilic additions occur, i.e. electron-acceptors substituents increase, and electron-donating reduce the reactional activity of aldehydes in the reactions of nucleophilic additions. For this reason, aromatic radical, which is in the conjugation with carbonyl group manifests stronger electron-donating effect, than aliphatic radicals, i.e. aromatic aldehydes are less reactive than aliphatic ones. The certain influence on the reactivity of carbonyl compounds provide steric factors: bulky substituents decrease the rate of the reaction. Amines due to the relatively high basicity are easily joined to aldehydes. Due to the higher nucleophilicity primary and secondary amines are joined to aldehydes without adding acid, i.e. reaction proceeds without catalyst.
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