Chemistry of ethyleneimine

The mechanism of the reaction of N-aminoethyleneimine with some aliphatic aldehydes and with acrolein have been studied. It has been shown that the reaction takes place at the carbonyl bond C=O with the formation of hydrazones.For part II, see [1].     

Chemistry of ethyleneimine

Tetramethyltetrazene, cyanoacetaldehyde N,N-dimethylhydrazone, glyoxal N,N-bis(dimethylhydrazone), glyoxylic acid nitrile N,N-dimethylhydrazone, and 1,4-dimethylamino-2,5-dicyanodihydropyrazine are formed by reaction of 1-chloro-1-cyano-2-(2,2-dimethylhydrazino)ethane with sodium hydride.     

Chemistry of ethyleneimine

The configuration of 2-substituted 1,3-diazabicyclo[3.1.0]hexanes was studied by means of PMR spectroscopy. When R R, it was proved that they exist in endo and exo forms, and equilibrium between both forms was detected in solutions in the case of 2-aryl-substituted derivatives. Conversion of the endo to the exo form is observed in crystals under the influence of x-ray irradiation.See [1] for communication IX.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 925–935, July, 1975.     

The chemistry of ethyleneimine

The reaction of N-aminoethyleneimine (I) with substituted benzenesulfonyl chlorides (II) has been studied. The main products of the heterolysis of the ring are substituted N-(-chloroethyl)benzenesulfonohydrazides (V). The structure of V has been shown by IR, UV, and PMR spectroscopy, and also by independent synthesis.For part III, see [23].     

The chemistry of ethyleneimine

The structure of the products of the reaction of -hydrazinoethyl hydrogen sulfate with aldehydes has been studied. In an alkaline media, the condensation products are converted into hydrazones of N-aminoethyleneimine or the corresponding azines. The structure of the cyclization products was shown by UV, IR, and PMR spectroscopy.For part IV, see [1].     

The substitution structure of ethyleneimine

The substitution structure (r_s) of ethyleneimine (aziridine) has been found by analysis of microwave gas spectra of the parent molecule and of the necessary number (5) of mono-isotopically substituted species, all of which were chemically enriched. Two coordinates (<0.1 Å) had to be derived using the conditions Σm_ic_i = Σm_ib_ic_i = 0. Data from microwave spectra of two double-isotopically substituted species [1-D]-, [1−¹⁵N]-ethyleneimine, and [2,2'-D₂]-ethyleneimine were applied as a further check. The agreement was satisfactory. In the resulting r_s structure the C-C distance is shorter than the C-N distance, in accordance with the larger nuclear charge of nitrogen compared to carbon, but qualitatively disagreeing with the results of earlier investigations. Also, the plane defined by H(2), C(2), H(2') is not perpendicular to the N(1), C(2), C(3) plane as assumed earlier. The former plane forms and angle of 87° with the latter which, however, almost exactly bisects the HCH angle. The CH₂ groups may, therefore, be described as slightly “twisted”.     

Synthesis of some ethyleneimine derivatives of pyrimidine

It has been shown that 2, 6-dichloto-4-methylpyrimidine reacts with ethyleneimine in benzene solution in the presence of triethylamine or in an aqueous alkaline medium with the formation of 6-chloro-2-ethyleneimino-4-methylpyrimidine. The condensation of 2, 6-di-chloro-4-methyl-5-nitropyrimidine with an excess of ethyleneimine and in benzene solution in the presence of triethylamine has given 2, 6-diethyleneimino-4-methyl-5-nitropyrimidine.     

Thermodynamic Properties of N-(Trimethylsily)ethyleneimine N-(Triethylsily)ethyleneimine and (Dimethylphenylsilyl)ethyleneimine Complexes with Zinc Chloride in the Range 0-340 K

Tmperature dependence of heat capacity of N-(trimethylsilyl)ethyleneimine, N-(triethylsilyl)-ethyleneimine, N-(dimethylphenylsilyl)ethyleneimine with zinc chloride was studied in the 5-340 K rangein an adiabatic vacuum calorimeter with 0.2% error. From the data obtained tge complexes thermodynamicfunctions C0 _p(T), H ⁰(T)-H ⁰(0), S ⁰(T)-S ⁰(0) and G ⁰(T)-H ⁰(0) are obtained in the 0-340 K, as well as fractal dimensions D and characteristic temperatures max for the functions of gractal heat capacity of solid substances.     

Synthesis and characterization of poly(ethyleneimine) dendrimers

Poly(ethyleneimine) (PEI) dendrimers up to the third generation (G3) were prepared by a divergent synthesis method from an ethylenediamine (EDA) core. The amine terminals were bonded with vinylbromide by a Michael addition reaction. Then, the bromide terminals were converted to amine groups using a Gabriel amine synthesis method. PEI dendrimers displayed pH-dependent luminescence, and their emission intensities at pH 6 increased over time. Fluorescence intensities also increased with increasing dendrimer generation from G1 to G3. Air-bubbling in aqueous solutions of dendrimers made to incorporate detectable amount of oxygen in dendrimers. EDA also behaved similarly in luminescence and oxygen incorporation.

Synthesis of bifunctional monodisperse poly(N-isovaleryl ethyleneimine)

A bifunctional initiator, ethanediyl 1,2-bis(2-isobutyl oxazolinium trifluoromethane sulfonate) was prepared and used for the ring opening polymerization of 2-isobutyl oxazoline. Polymerizations were run in CH₃CN at 80 and 60°C and in sulfolane at 80°C. The molecular weight distributions of the poly(N-isovaleryl ethyleneimine)s produced, M/I ≤ 45, approached Poisson distribution.     

A Hyperbranched Poly(ethyleneimine) Grown on Surfaces

Aminosilylated substrate was treated with aziridines in order to prepare hyperbranched polymers on solid supports such as silicon wafer and fused silica. It is observed that the primary amine on the substrate is good enough to initiate the ring-opening polymerization of aziridine. Measuring the thickness of the film and the absolute density of the primary amine functionality shows that a very highly branched poly(ethyleneimine) is formed upon the reaction. The surface density of the primary amine functional group (-NH(2)) on the very top surface increased dramatically (from 3.5 amines/nm(2) to 66 amines/nm(2)). A protected aziridine, benzyl 1-aziridinecarboxylate, was employed for the stepwise growth of the film. Two step-processes, chain growth and deprotection, were successful in growing the molecular layer, and a linear chain was formed without branching. Copyright 2000 Academic Press.     

Structural changes in poly(ethyleneimine) modified microemulsion

The influence of branched poly(ethyleneimine) on the phase behavior of the system sodium dodecylsulfate/toluene-pentanol (1:1)/water has been studied. The isotropic microemulsions still exist when water is replaced with aqueous solutions of PEI (up to 30% in weight), but their stability is significantly influenced. From a polymer concentration of 20 wt%, the polymer enhances the solubilization of water in oil, changes the sign of the spontaneous curvature of the surfactant film, and induces an inversion of the microemulsion type from water-in-oil (L(2)) to oil-in-water (L(1)), by the formation of a bicontinuous channel. Further investigations show that the addition of polymer in the L(2) phase changes the droplet-droplet interactions as the conductivity drops and the percolation disappears. In the bicontinuous channel, higher viscosities can be detected, as well as a weak percolation followed by a steep increase of the conductivity, which can be related to evident structural changes in the system. DSC measurements allow then to follow the changes of the water properties in the system, from interfacial-water in the L(2) phase to free-water in the sponge-like phase. Finally, all the measurements performed permit to characterize the structural transitions in the system and to understand the role of the added polymer.     

Reactions of derivatives of amino- and mercapto-sym-triazines with ethyleneimine and ethylenediamine

It was established that the action of ethyleneimine on mercapto- and cyanamino-sym-triazines gives 2-aminoethylthio- and iminoimidazolidinyl-sym-triazines. The latter are also obtained from salts of cyanamino-symtriazines with ethylenediamine by heating. The 2-aminoethylthio derivatives were tosylated and phenylcarbamoylated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 818–821, June, 1993.     

Synthesis and characterization of side-chain liquid-crystalline poly(ethyleneimine)s with cyanobiphenyl groups

A series of polyethyleneimine-based side-chain liquid-crystalline polymers substituted with different ratios of cyanobiphenyl as pendent mesogenic groups has been synthesized in which the spacer length varies between two and six methylene units. The structures of the synthesized polymers are confirmed by infrared and ¹H nuclear magnetic resonance spectroscopy. The thermal properties of these polymers have been investigated using differential scanning calorimetry, polarized optical microscopy and X-ray diffraction. The results indicate that the thermal behaviour of the polymers is strongly dependent on the degree of substitution. Polymers containing more than 69% of mesogenic groups exhibit nematic-type thermotropic liquid-crystalline behaviour with schlieren textures. Below this limit, the polymers are amorphous. Polymers with a higher degree of substitution present the crystalline states. The phase transition temperatures increase and the mesomorphic temperature ranges widen with increasing degree of substitution. The clearing temperatures decrease as the spacer length increases. An odd-even effect in the clearing temperatures is observed and the odd members display the higher values.     

法庭化学与化学

简单叙述了法庭化学与化学的关系，法庭化学是化学的一个特殊组成部分，化学的发展促进法庭化学的发展，法庭化学在侦破案件中起重要作用。本文还介绍了法庭化学研究的内容及与相关学科的关系。