Chemical modification of the structure and properties of epoxy polymers in the application of chloraniline hardeners

Results of modification of the structure and properties of epoxy polymers based on ED-20 epoxydiane resin hardened by aromatic amines are considered. Condensation products of chloroanilines obtained by the reduction of chloronitrobenzenes with formaldehyde and diethylenetriamine are used as aromatic amines.     

Effect of plasticization by amines on the physical properties of an acidic styrene copolymer

The dynamic mechanical properties of partly sulfonated (8.1 mole%) polystyrene were investigated at a frequency of ca. 1 Hz, following neutralization with various low molecular weight flexible and rigid amines. IR spectroscopic evidence suggested that the protonated amine units were possibly H-bonded to the sulfonate anion. Neutralization with flexible amines was found to result in a decrease in the glass transition temperature T_g by an amount proportional to the number of carbon atoms in the amine, while neutralization with rigid amines was found to result in an increase in T_g. It was also observed that the amines were more miscible with the sulfonated material than with polystyrene. It was concluded that the changes in properties observed upon neutralization are similar to those expected from a graft.     

Reactive ligands in radical processes catalyzed by copper complexes

The effect of the reactivity of donor ligands on the catalytic properties of copper complexes in the oxidative dimerization of mercaptans is considered. Catalytic compositions containing metal complexes in an excess of organic reagent ligands, which can show pronounced reductive properties (aromatic amines) or, on the contrary, oxidative properties (dimethyl sulfoxide) toward substrates, exhibit the greatest activity. In the course of the oxidation of mercaptans catalyzed by copper complexes, redox reactions accompanied by not only a change in the oxidation state of the metal but also the direct interaction of a substrate with an organic donor occur. In the presence of aromatic amines, the coupled oxidation of thiols and amines occurs, whereas dimethyl sulfoxide participates in the reaction as an oxidizing agent.     

Self-assembled organogels based on two-component system

Organogels were produced by the self-assembly of two organogelators, 3,5-bis(dodecanoylamino)benzoic acid and aromatic amines, in nonaromatic hydrocarbon solvents, through hydrogen bonding, aromatic stacking, and van der Waals interactions. 3,5-Bis(dodecanoylamino)benzoic acid has one carboxylic acid group for hydrogen bonding with amines and two alkylamide groups that can participate in interlayer hydrogen bonding and van der Waals interactions. The shape and size of the aromatic amines have a significant effect on the gel properties as well as their structures. A variety of organogels were realized by forming complexes of 3,5-bis(dodecanoylamino)benzoic acid and various amines with an aromatic group in nonaromatic hydrocarbon solvents.     

Use of Amines as Complex-Action Additives to Butadiene-Vinylidene Chloride Latex

The suitability of amines with different structures for modifying ready-for-use butadiene-vinylidene chloride latexes was examined. The influence of the amines on the main physicochemical properties of the latexes was elucidated.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 655-657.Original Russian Text Copyright © 2005 by Ivanova, Averko-Antonovich.     

Liquid-vapor distribution of amines and acid ionization constants of their ammonium salts in aqueous systems at high temperature

Ammonia and volatile organic amines are used to treat the water in steam generating systems to afford protection of the steam- and feedwater circuits from corrosion by acidic condensate. The base strength and the volatility of the reagent used are two important parameters that have bearing on its ability to inhibit corrosion; they determine the pH of the solution produced from condensing steam. The distribution of thirteen amines between water and steam in the temperature range 150 to 325°C was studied. The amines were chosen on the basis of their known room-temperature base strength. The acid ionization constant of the ammonium salts of seven of these amines was determined by conductivity measurement in the temperature range 25 to 275°C. Amines with high room-temperature base strength and distribution coefficient in the optimum range were chosen for the high-temperature base strength determination. The results of these studies were used to estimate the effectiveness of these amines in raising the pH of the condensate from steam containing carbon dioxide and acetic acid, to provide the basis for further studies on the corrosion inhibition properties of the amines.     

Selective synthesis of α-trifluoromethyl-β-aryl enamines or vinylogous guanidinium salts by treatment of β-halo-β-trifluoromethylstyrenes with secondary amines under different conditions

Unprecedented selective reactions of β-halo-β-trifluoromethylstyrenes with secondary amines under different conditions were discovered. Depending on the electronic properties of the starting styrenes and the reaction parameters, two pathways were found. With neat secondary amines a series of α-trifluoromethyl-β-aryl enamines were prepared in high yields. In contrast, the reactions of the mentioned styrenes with the same amines in polar solvents by substitution of all halogen atoms gave vinylogous guanidinium salts. Possible reaction mechanisms are discussed.     

Spectroscopic Study of Molecular Recognition of Ions by Chromogenic Calix[4]arene Derivatives

The complexation properties of three new chromogenic calix[4]arenes ( 1a–c) with aliphatic amines and alkali/alkali earth metal ions have been studied by UV/Vis spectroscopy. 1c shows the greatest complex forming ability and it is selective for Li⁺, Ca²⁺ and certain amines in polar solvents.     

Liquid-crystalline behaviour of 4-(ω-aminoalkyloxy)-4'-cyanobiphenyls and their side chain epoxy polymers

Liquid-crystalline side chain polymers were obtained from the ring-opening reaction of epoxy resin with mesogenic amines, 4-(ω-aminoalkyloxy)-4'-cyanobiphenyl. The amines with the alkyl group ranging from five to nine methylene units were synthesized, and were found to exhibit an enantiotropic nematic phase. Polymerization of these amines with ethylene glycol diglycidyl ether at 100°C yielded the polymers of low glass transition and melting temperatures. The mesomorphic properties of the amines and the resulting epoxy polymers are reported.     

The Quarternisation of Tertiary Amines with Dihalomethane

Whereas dichloromethane is inert towards reaction with most tertiary amines under atmospheric conditions, it readily reacts with a wide variety at high pressures to produce α-chloro quaternary ammonium and even bis-ammonium salts. The reaction of dichloromethane and dibromomethane with eleven tertiary amines and properties of the products are described.     

Hydrogen bonding by alcohols and amines

The pure base calorimetric method has been used to determine the enthalpies of hydrogen bond complex formation between aliphatic amines and alcohols. The enthalpies of complexation for the series methanol-n-butanol bonding with triethylamine increase with decreasing alkyl chain length in accordance with the electron donating properties of alkyl groups. Unexpectedly, the enthalpies for the complexes of n-butanol with tributylamine, tripropylamine, and triethylamine increase with decreasing alkyl chain length.Primary and secondary amines form hydrogen bonded complexes with n-butanol in which the amine protons form an NH···O bond with the alcohol and the alcohol hydroxyl proton donates a proton to the amine nitrogen. The difference in enthalpy of complex formation between tertiary amines and secondary amines is largely accounted for by the involvement of the amine proton of the secondary amine. Primary amines, like secondary amines, donate only one proton to the complex with n-butanol but have a larger complex enthalpy than secondary amines probably because of steric hindrance and differences in basicity.     

Synthesis and physico-analytical studies of some novel ferrocenyl Schiff base derivatives

A series of ferrocenyl Schiff base derivatives was synthesized by condensation reactions of 1,1′-ferrocenedicarboxaldehyde and aromatic amines containing long chain alkyl groups as free ends which were characterized by their physical properties, elemental, FTIR, ¹H NMR, ¹³C NMR spectral and thermal analysis. The thermal behaviour of the synthesized compounds was studied by differential scanning calorimetry (DSC) which revealed that these compounds may exhibit mesomorphic properties. The DSC results of aromatic amines and ferrocenyl Schiff bases were compared to study the effects of structure, i.e. rigid core and terminal chain length, on the phase transition behaviour.     

Combination of different chemical surface reactions for the fabrication of chemically versatile building blocks onto silicon surfaces

The use of nucleophilic displacement reactions on bromine-terminated monolayers is presented to create new functional moieties onto silicon surfaces. Functional amines were used as suitable nucleophiles to introduce versatile building blocks onto self-assembled monolayers to perform further surface chemistry toward the fabrication of surfaces with designed properties by combining compatible chemical routes. These modified substrates were analyzed by suitable surface sensitive techniques. Furthermore, the functional monolayers were used for different postmodification reactions. For example, functional amines facilitated with acetylene groups were applied in the click chemistry approach. The use of amino-functionalized terpyridine units leads to the construction of supramolecular systems, where the choice of the metal monocomplex for the complexation is important for the tuning of the surface properties.     

Co-Assembly of Chiral Amines and a Four-Armed Cyano-Substituted Luminophore through Hydrogen Bonds for Potential Development of Smart Chiroptical Materials

Chirality transfer from chiral molecules to assemblies is of vital importance to the design of functional chiral materials. In this work, selective co-assembly behaviors between chiral molecules and an achiral luminophore, potentially driven by the intermolecular salt-bridge type hydrogen bonds are reported. Cyano-substituted tetrakis(arylthio)benzene carboxylic acid ( TA ) served as the luminophore and hydrogen bond donors, which underwent co-assembly with different chiral amines. It was found that structures of chiral amines affect the chirality transfer and the properties of co-assemblies due to effects on hydrogen bonds and stacking pattern. Only in specific co-assemblies, the chiroptical properties occurred at both ground state and excited states based on the emerged Cotton effects and circularly polarized luminescence (CPL) signals, revealing that the chirality was successfully transferred from molecular level to supramolecular level. In addition, accurate quantitative examination of chiral amines was realized by circular dichroism (CD) spectra. This work demonstrates the characteristic chirality response and transfer through co-assembly, providing a potential method to develop smart chiroptical materials.     

Reaction Mechanism in Ionic Liquids: Kinetics and Mechanism of the Aminolysis of 4‐Nitrophenyl Acetate

In this work, we report a kinetic study of the reactions of the title compound with secondary alicyclic amines at different temperatures in acetonitrile and several ionic liquids (ILs). From this study, we have described that the reactions in MeCN and in the studied ILs occur by a concerted mechanism and that the activation parameters are sensitive to the structural properties of the ILs. The pKa values of all amines used in both MeCN and ILs were determined.     

A molecular mechanics force field for conformational analysis of aliphatic acyclic amines

An improved molecular mechanics force field for conformational and vibrational studies of aliphatic acyclic amines is developed. The resulting force field reproduces molecular structures adequately and provides a good fit for energy differences between conformers and barriers to internal rotation for a large number of amines. In addition, vibrational frequencies are calculated in good agreement with available experimental data. When compared with existent force fields for amines, the present force field is considerably more simple and gives rise to calculated properties in closer agreement with experiment.     

直链饱和一元胺物理性质递变规律研究

以直链饱和一元胺同系物结构重复单元数值连续变化为模型假定 ,获得了描述直链饱和一元胺同系物物理性质递变规律的数学表达式 :P =a +bnc,其中a、b、c均为常数 ,n为结构重复单元数值 ,P为直链饱和一元胺同系物的物理性质 .通过非线性回归分析 ,得到回归方程 ,结果表明直链饱和一元胺同系物的物理性质与重复单元数值之间满足上述关系式 ,均显示优良的相关性     

Ring expansion of cyclic β-amino alcohols induced by diethylaminosulfur trifluoride: synthesis of cyclic amines with a tertiary fluorine at C3

As the replacement of a hydrogen atom by a fluorine atom in a compound can have an important impact on its biological properties, the development of methods allowing the introduction of a fluorine atom is of great importance. The scope and limitations of the ring expansion of cyclic 2-hydroxymethyl amines induced by diethylaminosulfur trifluoride (DAST) to produce cyclic β-fluoro amines was studied as well as the enantioselectivity of the process.     

Ni-exchanged montmorillonite with methyl-, dimethyl- and trimethylamine and their thermal properties

The influence of different steric properties of methylamine (MA), dimethylamine (DIMA) and trimethylamine (TRMA) on the type of interactions with Ni-exchanged montmorillonite and thermal properties of these materials were studied. The results of diffraction, spectral (IR) and thermal (TG, DTG) analysis show that MA, DIMA and TRMA are intercalated into the interlayer space of montmorillonite. Thermal decomposition in the temperature interval 20–450°C of studied samples with MA and DIMA proceeds in three steps (the release of chemisorbed amines, coordinated amines and alkylammonium cations) while the sample with TRMA decompose only in two steps (the peak corresponds to the release of coordinated TRMA is absent). The effect of different steric properties of individual amines is evident.     

The Glc Separation of Indole Amines and Indole Alcohols as Heptafluorobutyryl Derivatives

Abstract

Indole amines and indole alcohols were converted to heptafluoro-butyryl (HFB) derivatives by an acyl transfer reaction with heptafluoro-butyrylimidazole. The indole NH group as well as all amino and hydroxyl groups were acylated. The HFB derivatives have excellent gas chroma-tographic properties and can be used with either hydrogen flame or electron capture detection systems. Mass spectra of the HFB derivatives of biologic N, N-dialkyl indole amines are very characteristic; these compounds can be identified easily by GLC-MS methods.