Registration Number
0217U004085,
0116U002519
, R & D reports
Title
Regioselective synthesis of epoxy compounds with different topologies
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Head
Shved Olena M., Доктор хімічних наук
Registration Date
13-01-2017
Organization
Donetsk State University
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The behavior of amines as catalysts for oxirane acidolysis and phenolysis has been studied using kinetic methods. The apparent catalytic and noncatalytic reaction rate constants have been estimated. It has been demonstrated that the noncatalytic pathway has almost no effect on the apparent reaction rate constant. In order to determine the character of the behavior of amines (bases/nucleophiles) in this reaction, their reactivity has been analyzed within the conceptions of basic and nucleophilic mechanisms of catalysis. Based on the quantitative amine structure—catalytic activity correlation, it has been shown by comparing the values of correlation coefficients (r) of equations describing mechanisms for various reaction systems that, in the reactions of oxiranes with proton donors (carboxylic acids and phenols), the catalytic activity of tertiary amines/pyridines is determined by their nucleophilicity rather than basicity. The effect structure have on the rate of reactions between X-substituted trans-4,4'-dinitrostilbene oxide and Y-substituted arylsulfonic acids in a mixture of dioxane with 1,2-dichloroethane (7: 3 vol/vol) at 265 K is studied. It is found that as a result of the nonadditivity of the joint effect of substituents X and Y on the rate of the process of oxirane ring opening. The possibility of using isoparametric points as quantitative mechanistic criteria is demonstrated. The kinetics and scheme reaction of epoxy resin ED-20 homopolymerization in the presence of amines with boron trifluoride complexes are investigated. It is shown the complexes are decomposed under the epoxy resin's action with amine releasing and formation new complex ED-20·BF3 at the initial process' stage. The presence of the last one promotes the two directions of reaction: the 1st - the catalysis of ED-20 homopolymerization by BF3 and the 2nd - curing ED-20 by primary and secondary amines or the catalysis of ED-20 homopolymerization by tertiary amines. The contribution of each directions depends on the amine nature. The cationic polymerization process of the resin under the influence BF3 (the 1st direction) competes with the curing process of the resin highly basic primary and secondary amines (the 2nd direction). In the case of complexes lowly basic primary and secondary, and tertiary amines, significant contribution to the rate of the process makes first direction. Various directions of amines' reaction with epoxy help to explain a monotonic increase in the activity of the primary and secondary amines with an increasing of the basicity (nucleophilic substitution reaction), and abnormally low activity of tertiary amines (step-growths polymerization). Epoxy-silica and epoxy-titania composites of cationic polymerization and amine curing based on epoxy resin EPONEX 1510 were synthesized via sol-gel method. It was found that increasing of filler content in the obtained composites from 0,5 to 3 wt. % leads to imperfection of topological structure of epoxy matrix, raise of sol-gel fraction yield and decrease of glass transition temperature. According to scanning electron microscopy analysis data silica particles' size in the composites varies from 80-120 to 400 nm.
Product Description
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Беспалько Юлія Миколаївна
Жильцова Світлана Віталіївна
Калінський Олександр Михайлович
Леонова Наталя Геннадіївна
Ситник Наталія Сергіївна
Швед Олена Миколаївна
Шпанько Ігор Вальович
Ютілова Ксенія Сергіївна
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2020-04-02
