Vergleichende Untersuchungen zur Silicationenkonstitution in [(Ethyl)n(2-hydroxyethyl)4−nammonium]-Silicatlösungen mit n von 3 bis 1 und zum Einfluß von Alkalihydroxid

Comparing Investigations on the Silicate Constitution in [(Ethyl)_n(2-hydroxyethyl)_4?n-ammonium] Silicate Solutions with n from 3 to 1 and on the Influence of Alkali Hydroxide In [(ethyl)_n(2-hydroxyethyl)_4?nammonium]-silicate solutions with n from 3 to 1, free of alkali hydroxides, double three-ring and double four-ring silicate anions are to be found. With a growing number of 2-hydroxyethyl groups contained in the ammonium ion, the part of double four-ring ions increases. Other influating factors are the molar ratio of organoammonium hydroxide to silicon dioxide and the SiO₂-concentration. Admixtures of alkali hydroxides modify the ratio of double three-ring to double four-ring ions and cause also a degradation of both kinds of silicate ions, the effect of sodium hydroxide surpassing that of potassium hydroxide.     

Untersuchungen zur Silicationenkonstitution in Trimethyl- und Triethyl-2-hydroxyethylammoniumsilicatlösungen

Investigation on the Silicate Constitution in Trimethyl- and Triethyl-2-hydroxyethyl-ammoniumsilicate Solutions In trimethyl-2-hydroxyethyl-ammoniumsilicate solutions with molar N:Si ratios of 1:1 to 2:1 only double four-ring silicate anions are observed. In triethyl-2-hydroxyethyl-ammoniumsilicate solutions with the same molar N:Si changing quantities of double three-ring and double four-ring silicate anions are detectable. There is a range of SiO₂ concentrations, where these two silicate anion constitutions dominate among all the SiO₂ existing in the solutions. Increased quantities of alkali hydroxides effect the decomposition of double ring silicates, the decomposing effect of sodium and potassium hydroxide differing in their strength.     

Über die Silicatanionenkonstitution in Tetraethylammoniumsilicaten und ihren wäßrigen Lösungen

On the Constitution of Silicate Anions in Tetraethylammonium Silicates and their Aqueous Solutions Investigations by paperchromatography, ²⁹Si-NMR spectroscopy and trimethylsilylation method show that concentrated solutions of tetraethylammonium (TEA) silicates with molar TEA:Si ratios from 2.8 to 1 contain mainly double three-ring silicate anions. Besides of these small amount of mono-, di-, tri-, tetra-, cyclotri-, cyclotetra-, double four-ring- and other polycyclic silicate anions are present. From these solutions a crystalline double three-ring silicate of the formula [N(C₂H₅)₄]₆[Si₆O₁₅] · 57 H₂O could be obtained by crystallization at low temperature. Concentrated solutions with TEA:Si ratios of 0.8 to 0.6 contain mainly double three-, double four-, double five- an probably double six-ring silicate anions. From such solutions always the solid TEA-double four-ring silicate is obtained by crystallization. The reasons for the prefered formation of double ring silicate anions in TEA-silicate solutions and their crystallization are discussed.     

Zum Anionenaufbau von Tetra-n-butylammoniumsilicaten und ihren wäßrigen Lösungen

On the Anion Constitutions of Tetrabutylammonium Silicates and their Aqueous Solutions The anion distribution of tetra-n-butylammonium-(TBA)-silicate solutions with molar TBA/SiO₂ ratios between 0.6 and 4 and silica concentrations between 0.1 M and 2.2 M has been investigated by trimethylsilylation and ²⁹Si NMR techniques. In contrast to concentrated tetramethylammonium- and tetraethylammonium silicate solutions in TBA silicate solutions a preference of double ring silicate anions does not occur. In TBA silicate solutions a broad distribution of silicate anions consisting of monomeric, oligomeric chain and ring, as well as polymeric silicate anions has been observed. Crystalline TBA silicates with TBA/SiO₂ ratios of 0.78 to 1 contain mainly double five-ring silicate anions Si₁₀O₂₅^10? whereas for TBA/SiO₂ ratios higher than 1.4 the double three-ring anion Si₆O₁₅^6? predominates. A recently prepared TBA silicate with low TBA content (TBA/SiO₂ = 0.23) has been found to consist of double four-ring silicate anions with 6 SiOH groups per double four-ring.     

Attenuated total reflectance fourier transform infrared analysis of fly ash geopolymer gel aging

Structural changes in fly ash geopolymers activated with different sodium hydroxide and silicate concentrations are investigated using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy over a period of 200 days. A strong correlation is found between the concentration of silicate monomer in the activating solution and the position of the main Si-O-T stretching band in the FTIR spectrum, which gives an indication of the relative changes in the gel Si/Al ratio. The FTIR spectra of geopolymer samples with activating solution concentrations of up to 1.2 M SiO2 indicate that an Al-rich gel forms before the final gel composition is reached. The time required for the system to reach a steady gel composition depends on the silicate activating solution concentration and speciation. Geopolymers activated with solutions containing predominantly high-order silicate species rapidly reach a steady gel composition without first forming an Al-rich gel. A minimum silicate monomer concentration of approximately 0.6 M is required to shift the geopolymer synthesis mechanism from hydroxide activation to silicate activation. Silicate speciation in the activating solutions also affects zeolite formation and geopolymer microstructures, with a more homogeneous microstructure and less zeolite formation observed at a higher SiO2 content.     

Über die Konstitution der Silicatanionen im Kobaltäthylendiaminsilicat

On the Constitution of Silicate Anions in Cobalt Ethylenediamine Silicate A crystalline and acid-soluble silicate of the composition 1 Co₂O₃ · 6 en · 7.2 SiO₂. 26 H₂O was obtained by the reaction of cobalt ethylenediaminehydroxide solution with tetramethoxysilane. Chemical, kinetic, chromatographic, and x-ray investigations showed that this silicate is an acid double four-ring silicate of the formular [Co(en)₃]₂[H₃Si₈O₂₀] · 16–28 H₂O. The preparation of a cobalt propylenediamine (l,2 and 1,3)-silicate is described.     

Anionenstrukturen in Alkalisilicatschmelzen

Silicate Anions in Alkali Silicate Melts Melts of alkali silicates with molar ratios of alkali (Li, Na, K, Cs) to silicon between R = 4.0 and ca. 2.0 were prepared, quenched and worked up to the trimethylsilyl silicic acid esters. These were identified by comparison to the GC and silicon-29 NMR data of trimethylsilyl silicic acid esters from other sources. It was found that with cations of Li and Na mostly linear silicates were formed. But with the cations of K and Cs a considerable amount of the cyclic species Si₆O₉^6? was present. Branched silicates were of minor importance only. Besides the alkali silicon ratio, the temperature of the melt before quenching influences the composition of the silicate mixture.     

Herstellung und Anionenkonstitution von kristallinen Tetramethylammonium-alumosilicaten und -alumosilicatlösungen

Synthesis and Anion Constitution of Crystalline Tetramethylammonium-aluminosilicates and -aluminosilicate Solutions Crystalline tetramethylammonium aluminosilicates with molar constitutions of wN(CH₃)₄OH · xSiO₂ · y Al₂O₃ · zH₂O and w = 1 to 1.2; x = 1; y = 0.02 to 0.5; z = 8.1 to 9.7 has been obtained from mixtures of diluted TMA aluminate and TMA silicate solutions with different molar Si/Al ratios by concentration and cooling down of the mixtures. Investigations of the TMA aluminosilicates by means of trimethylsilylation method show that the structure of the TMA aluminosilicates consists of double fouring units in analogy to the aluminum free TMA silicates. The arrangement of the Al atoms in the double four-rings agrees in general with Loewenstein's rule and leads to five distinct types of double four-rings with different Al content and Si? Al distribution. By the methods used in this study no distinction can be made between monomeric or polymeric arrangements of the double four-ring units. The existence of aluminosilicate anions in aqueous solutions is discussed.     

Physicochemical properties and microstructure formation of the surfactant mixtures of sodium N-(2-(n-dodecylamino)ethanoyl)-L-alaninate and SDS in aqueous solutions

Aggregation behavior of a novel anionic amphiphilic molecule, sodium N-(2-(n-dodecylamino)ethanoyl)-L-alaninate (C(12)Ala), was studied in the presence of sodium dodecyl sulfate (SDS) surfactant at different [C(12)Ala]/[SDS] molar ratios and concentrations. The viscosity of aqueous SDS solution increased in the presence of C(12)Ala surfactant. The bulk viscosity of water was found to increase upon increase of both molar ratio and total surfactant concentration. The microenvironments of the self-assemblies were investigated using the fluorescence probe technique. Fluorescence anisotropy studies indicated formation of rodlike micelles. Both dynamic light scattering and small-angle neutron scattering measurements were performed to obtain the size and shape of the microstructures. The concentration and composition dependence of the hydrodynamic diameter of the aggregates were investigated. Transmission electron micrographs revealed the presence of a hexagonal liquid crystal phase in dilute solutions of the C(12)Ala-SDS mixture. The micrographs of moderately concentrated solution, however, showed cholesteric liquid-crystal structures with fingerprint-like texture. Temperature-dependent phase behavior of the self-assemblies was studied by use of the fluorescence probe technique.     

N-（2-甲基）苯基甘氨酸的三价和四价金属/非金属衍生物(英)

用N-（2-甲基）苯基甘氨酸合成了几种（硼、铝、铁、砷和锑）及四价（硅、钛和硒）金属/非金属衍生物。合成是在苯溶液中采用了金属/非金属的异丙氧基化合物和N-（2-甲基）苯基甘氨酸按1∶1和1∶2的配比完成的。一般情况下，合成的产物均为有色固体，以及在产物中有异丙氧基基团残留而显吸湿性。对所制成的衍生物均采用了共沸混合物分析、元素分析和光谱测定等进行了表征。     

[TMPA]4[Si8O20] · 34 H2O and [DDBO]4[Si8O20] · 32 H2O are heteronetwork clathrates with 1,1,4,4-tetramethylpiperazinium (TMPA) and 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane (DDBO) guest cations

[TMPA]₄[Si₈O₂₀] · 34 H₂O ( 1 ) and [DDBO]₄[Si₈O₂₀] · 32 H₂O ( 2 ) have been prepared by crystallization from aqueous solutions of the respective quaternary alkylammonium hydroxide and SiO₂. The crystal structures have been determined by single-crystal X-ray diffraction. 1 : Monoclinic, a = 16.056(2), b = 22.086(6), c = 22.701(2) Å, β = 90.57(1)° (T = 210 K), space group C2/c, Z = 4. 2 : Monoclinic, a = 14.828(9), b = 20.201(7), c = 15.519(5) Å, β = 124.13(4)° (T = 255 K), space group P2₁/c, Z = 2. The polyhydrates are structurally related host-guest compounds with three-dimensional host frameworks composed of oligomeric [Si₈O₂₀]^8? anions and H₂O molecules which are linked via hydrogen bonds. The silicate anions possess a cube-shaped double four-ring structure and a characteristic local environment formed by 24 H₂O molecules and six cations (TMPA, [C₈H₂₀N₂]²⁺, or DDBO, [C₈H₁₈N₂]²⁺). The cations themselves reside as guest species in large, irregular, cage-like voids. Studies employing ²⁹Si NMR spectroscopy and the trimethylsilylation method have revealed that the saturated aqueous solutions of 1 and 2 contain high proportions of double four-ring silicate anions. Such anions are also abundant species in the saturated solution of the heteronetwork clathrate [DMPI]₆[Si₈O₁₈(OH)₂] · 48.5 H₂O ( 3 ) with 1,1-dimethylpiperidinium (DMPI, [C₇H₁₆N]⁺) guest cations.     

Über den Anionenaufbau wäßriger Tetra-n-propyl- und Tetraethylammoniumsilicatlösungen

On the Anion Constitutions of Aqueous Tetra-n-propylammonium and Tetraethylammonnium Silicate Solutions The constitution of the silicate anions present in 0.1 M to 3 M tetrapropylammonium-(TPA-) and tetraethylammonium-(TEA-)silicate solutions with molar TPA/Si ratios of 3, 1 and 0.6 and TEA/Si ratios of 3 and 1 is investigated by means of trimethylsilylation. Up to 16 different oligomeric silicate anions are detected and estimated quantitively. Type and quantitative dis-tribution of the silicate anions are very similar in diluted 0.1 M TEA- and TPA-silicate solutions. Concentrated TEA-silicate solutions contain preferably Si₆O₁₅^6? anions whereas concentrated TPA-silicate solutions are characterized by a broad distribution of different oligomeric silicate anions. The anion distribution of TPA- and TEA -silicate solutions is compared with the results of tetramethyl- and tetrabutylammonium silicate solutions studied previously.     

N-甲基-N-(2-甲基丙烯酰氧乙基)苯胺与其聚合物的荧光光谱

<正> 我们曾报道过甲基丙烯酸-4-N,N-二甲氨基苄酯(DMABMA)、N-(4-N′N′-二甲氨基苯基)代丙烯酰胺(DMAPMA)、8-丙烯酰氧喹啉(AQ)、N-丙烯酰-N′-苯基哌嗪(APP)等在同一分子中含有缺电子双键和给电子发色基团的单体及它们的聚合物在溶液中的荧光行为。在相同的链节克分子浓度下,这些单体的荧光强度比其聚合物的荧光强度低很多。我们将这种现象称为“结构自猝灭现象”。这种现象是由于共存在这类     

Untersuchungen zur Bildung von Doppelringsilicationen in Trimethyl-(2-hydroxyethyl)ammoniumsilicatlösungen

Investigation on the Formation of Double-ring Silicate Ions in Trimethyl-(2-hydroxyethyl) Ammoniumsilicate Solutions The formation of double-four ring silicate ions have been investigated after the mixing of Tetramethoxysilan with Trimethyl-(2-hydroxyethyl)ammoniumhydroxide in the molar ratio 1:1 (c_SiO2 = 1.53 mol · kg^?1) in dependence of the time. About 20–30% of the rapid hydrolysing esters has reacted to double-three- and double-four ring ions after a short time, whereas 70–80% first condense to oligomers and polymers. In the further course of reaction also the oligomers, the polymers and the intermediate formed double-three-ring species changes to double-four-ring ions. After three hours about 90% of the silicon dioxide is in the double-four-ring constitution.     

N-（5-氯-2-羟基苄基）氨基酸衍生物及其金属配合物的合成、表征及抑菌活性

以N-（5-氯-2-羟基苄基）氨基酸及其酯为配体,在室温下以水和甲醇为溶剂,采用分步法,以1∶1的摩尔比将配体与金属离子在弱碱性条件下混合,合成了20种未见报道的N-(5-氯-2-羟基苄基)氨基酸类金属配合物。 用核磁、红外和紫外光谱技术对其结构进行了表征。 证明在配合物中配体N-(5-氯-2-羟基苄基)氨基酸的羟基、胺基和羧基均参与了配位。 抑菌测试表明,N-(5-氯-2-羟基苄基)氨基酸类金属配合物的抑菌活性普遍高于其配体,尤其对白色念珠菌的抑菌效果更为明显,均高达100%。 对N-（5-氯-2-羟基苄基）席夫碱氨基酸酯的合成方法进行了优化,得到了较佳的合成工艺条件。     

Self-organization in aqueous solutions of thermosensitive statistical copolymers based on N-(dimethylamino)ethyl methacrylate

Thermo- and pH-responsive statistical copolymers of N-(dimethylamino)ethyl methacrylate and lauryl methacrylate were synthesized by free radical copolymerization. Obtained samples differed in content of hydrophobic components (3 and 6?mol. %). Their molar masses were close to 30,000?g/mol. Self-organization in buffer solutions of copolymers were studied using light scattering and turbidimetry. It was found that copolymers as well as of poly(N-(dimethylamino)ethyl methacrylate) were thermosensitive at pH?>?7. Phase separation temperatures of investigated solutions decreased with dilution and pH increasing. Growth of lauryl methacrylate content in copolymers caused the decrease in phase separation temperatures.     

The electrode behaviour of zinc in ternary alkaline electrolytes stabilized by silicate

The vapour pressure of alkaline solutions has been measured using a modified version of the Ramsay and Young method. The addition of potassium fluoride to 3 molar potassium hydroxide containing 0.15 molar potassium silicate lowers the vapour pressure to that of 8 molar potassium hydroxide. The ternary mixture of fluoride/hydroxide/silicate may be suitable for application in primary zinc/air cells, as the previously reported slurry region is still observed with this electrolyte. The limitations of this mixed electrolyte are discussed.     

Synthesis of boron chelates from N-(pyrid-2-YL)- and (N-4-methylpyrid-2-YL) cyanoacetamides and their tautomeric transformations

Chelate complexes in which the boron atom is bound to the pyridine N atom and the O atom of the deprotonated ligand were synthesized by reaction of N-(pyrid-2-yl)- and N-(4-methylpyrid-2-yl) cyanoacetamides. A new type of intrachelate tautomeric transformation was discovered: the complexes obtained can exist in solutions in the form of two tautomers, which are derivatives of acetimidic acid or the corresponding ketene N,O-acetals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 164–168, January, 1991.     

Photometric determination of N-(p-nitrophenyl)maleimide

A procedure has been developed for the photometric determination of N-(p-nitrophenyl)maleimide based on the formation of a salt of the acinitro form of N-(p-nitrophenyl)maleic acid monoamide, which is formed on the hydrolysis of maleimide in concentrated acetic acid. Maleimide is dissolved in concentrated acetic acid, and the obtained solution is neutralized with an alkali. A bright yellow color of the reaction product appears.     

Einfluß wasserlöslicher Polyelektrolyte aus 1,6-Hexamethylendiisocyanat und N-(2-Aminoethyl)-2-aminoethansulfonsaurem Natrium auf die Dispersionsbildung bei anionischen Polyurethanen

Zusammenfassung Polyelektrolyte wurden durch Umsetzung von 1,6-Hexamethylendiisocyanat und N-(2-Aminoethyl)-2-amino-ethansulfonsaurem Natrium hergestellt und als wäßrige Lösungen der acetonischen Lösung eines anionischen Polyurethans vor der Dispersionsbildung zugesetzt. Kontinuierliche Leitfähigkeitsmessungen während der Dispersionsbildung ergaben, daß oberhalb eines bestimmten Wassergehaltes die Leitfähigkeit mit steigender Polyelektrolytkonzentration abnimmt. Dies wird auf eine zum Teil reversible Partikelvereinigung zurückgeführt, bei der ein Einschluß von wäßriger Phase zwischen den geflockten Teilchen erfolgt. Der mittlere Partikeldurchmesser nimmt mit steigendem Polyelektrolytgehalt zu. Oberhalb einer kritischen Polyelektrolytkonzentration ist die Partikelvereinigung weitgehend irreversibel, wodurch die Bildung einer Dispersion verhindert wird.

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Summary Polyelektrolytes were prepared by reaction of 1,6-hexamethylene diisocyanate and the Na salt of N-(2-aminoethyl)-2-aminoethane sulfonic acid. Aqueous solutions of these polyelectrolytes were added to acetonic solutions of an anionic polyurethane before formation of the aqueous dispersion. Continuous conductivity measurements showed that above a certain water concentration the conductivity decreased with increasing amount of polyelectrolyte. This was attributed to an in part reversible association of particles with inclusion of water between the flocked particles leading to an increase of the mean particle diameter. Above a critical concentration of polyelectrolyte the association of particles becomes largely irreversible preventing the formation of stable dispersions.