Sur quelques réactions acide-base dans les solvants fortement basiques anhydres. II. Les amino-2 éthylamidures de sodium et de potassium

1969 ◽  
Vol 47 (19) ◽  
pp. 3509-3513 ◽  
Author(s):  
W. R. Heumann ◽  
A. Bouchard ◽  
L. Šafařík
Keyword(s):  
Hydrochloric Acid ◽  
Solid Product ◽  
Pure Nitrogen ◽  
Lithium Amide ◽  
Potassium Hydride ◽  
Basic Strength ◽  
Sodium Amide

Solutions of sodium 2-aminoethylamide in anhydrous ethylenediamine were prepared by dissolving ammoniacal sodium amide NaNH2 in ethylenediamine and removing the ammonia formed in vacuum. When these solutions were prepared and kept under nitrogen containing not more than about 5 p.p.m. of oxygen and 1 p.p.m. of moisture, they remained colorless and stable. Upon addition of benzene to these solutions, the pure amide precipitated as fine greyish–white crystals, which were also stable under pure nitrogen. The potassium 2-aminoethylamide was prepared in a similar way from ethylenediamine and potassium hydride. Its solid product resembles that of the corresponding sodium amide, but its solutions in ethylenediamine are less stable, rapidly turning dark brown because of polymerization. The basic strengths of these two 2-aminoethylamides were compared with the corresponding lithium amide by following potentiometrically the neutralization of ethylenediamine solutions of hydrochloric acid, p-methoxyphenol, water, and ethanolamine respectively. According to the heights of the potential jumps at the equivalence points the basic strength of the amides was found to increase in the order Na < Li < K.

Factors in Aldol Condensations of Alkyl Acetates with Benzophenone and Reversals by Sodium Amide Versus Lithium Amide. Metallic Cation Effects1

1960 ◽  
Vol 25 (8) ◽  
pp. 1296-1302 ◽  
Author(s):  
CHARLES R. HAUSER ◽  
WILLIAM R. DUNNAVANT
Keyword(s):  
Lithium Amide ◽  
Metallic Cation ◽  
Alkyl Acetates ◽  
Amide Versus ◽  
Sodium Amide

scholarly journals Eutectic Phenomenon of LiNH2-KH Composite in MH-NH3 Hydrogen Storage System

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1348 ◽  
Author(s):  
Kiyotaka Goshome ◽  
Ankur Jain ◽  
Hiroki Miyaoka ◽  
Hikaru Yamamoto ◽  
Yoshitsugu Kojima ◽  
...  
Keyword(s):  
Melting Point ◽  
Storage System ◽  
Atomic Mobility ◽  
Melting Points ◽  
Lithium Amide ◽  
Hydrogen Storage System ◽  
Lower Melting Point ◽  
Hydrogenation Temperature ◽  
The Individual ◽  
Potassium Hydride

Hydrogenation of a lithium-potassium (double-cation) amide (LiK(NH2)2), which is generated as a product by ammonolysis of litium hydride and potassium hydride (LiH-KH) composite, is investigated in details. As a result, lithium amide (LiNH2) and KH are generated after hydrogenation at 160 °C as an intermediate. It is noteworthy that the mixture of LiH and KNH2 has a much lower melting point than that of the individual melting points of LiNH2 and KH, which is recognized as a eutectic phenomenon. The hydrogenation temperature of LiNH2 in the mixture is found to be significantly lower than that of LiNH2 itself. This improvement of reactivity must be due to kinetic modification, induced by the enhanced atomic mobility due to the eutectic interaction.

REVERSIBILITY OF ALKENE OXYMERCURATION

1957 ◽  
Vol 35 (12) ◽  
pp. 1377-1383 ◽  
Author(s):  
A. Rodgman ◽  
D. A. Shearer ◽  
George F Wright
Keyword(s):  
Hydrochloric Acid ◽  
Trifluoroacetic Acid ◽  
Maximum Yield ◽  
Order Reaction ◽  
Second Order ◽  
Reversible Reaction ◽  
Second Order Reaction ◽  
Basic Strength

It has been shown that deoxymercuration (conversion of an α-oxyorganomercurial to the alkene) is a second-order reaction dependent on concentration of the mercurial and of the deoxymercurating acid. Moreover the rate of deoxymercuration increases with basic strength of the alkoxy substituent in the mercurial. This tendency would indicate that the rate was dependent on the strength of the acid used for deoxymercuration. The supposition has been proved by use of trifluoroacetic acid which decomposes α-2-methoxycyclohexylmercuric trifluoroacetate more slowly than does hydrochloric acid. The trifluoroacetoxymercurial decomposes to the extent of 35% whereas its synthesis is effected in 60% maximum yield from cyclohexene and mercuric trifluoroacetate. A measurable equilibrium is thus attained in this oxymercuration, though not necessarily because of a simple reversible reaction.

scholarly journals Synthesis of basic zeolite from coal fly ash and its reactivity in Knoevenagel reaction

2014 ◽  
Vol 6 (1) ◽  
Author(s):  
Zainab Ramli ◽  
Siti Haslina Ahmad Rusmili
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Static Condition ◽  
Knoevenagel Reaction ◽  
Crystallization Time ◽  
Single Product ◽  
Solid Product ◽  
Naoh Solution ◽  
Zeolite P ◽  
Basic Strength

Zeolite was hydrothermally synthesized from coal fly ash in NaOH solution and static condition, at various times of crystallization and treatment. Geltreated with ultrasonication before heating resulted in the formation of pure zeolite P (Na-P) while untreated gel formed a mixture of sodalite and Na-P. Pure zeolite P was produced in 5 days and stable up to 31 days of crystallization time without the trace of sodalite formed. The synthesized Na-P was then ion-exchanged with potassium (K-P) and cesium (Cs-P) ions in order to increase the basicity of the Na-P obtained. The reactivity of the catalysts was tested in Knoevenagel reaction between benzaldehyde and malononitrile, producing solid benzylidenemalononitrile as single product. The reactivity was measured by the time when the first solid product formed. K-P catalyst was found to be the most reactive followed by Cs-P and Na-P in which the reactivity depends more on the number of base sites as well as the basic strength of zeolite. In conclusion, zeolites synthesized from CFA is potential catalysts for the Knoevenagel reaction.

Sur quelques réactions acide–base dans les solvants fortement basiques anhydres. III. n-Butylamine

1971 ◽  
Vol 49 (11) ◽  
pp. 1895-1900 ◽  
Author(s):  
W. R. Heumann ◽  
L. Šafařík
Keyword(s):  
Hydrochloric Acid ◽  
Alkali Metal ◽  
Electrode Potential ◽  
Weak Acids ◽  
Pure Nitrogen ◽  
Potentiometric Measurements ◽  
Higher Temperature ◽  
Orange Color ◽  
Reddish Orange

Cesium is the only alkali metal to react with n-butylamine, even at higher temperature. The n-butylamides of Na and K were prepared by heating the amine with the respective alkali hydrides. The amides were obtained as crystalline greyish white powders, which are stable when kept under pure nitrogen. The neutralization of a series of monobasic acids of various strength in n-butylamine by these amides was studied potentiometrically using a platinum indicating electrode. Potential jumps ranging from 1550 mV for hydrochloric acid to about 110 mV for diphenylmethane were obtained. The latter compound was the least acidic [Formula: see text] to react with the bases, while toluene [Formula: see text] did not react. The [Formula: see text] value of n-butylamine should therefore be about 37 to 38. Several dibasic acids and mixtures of two acids were also neutralized. The power of differentiation of the n-butylamine/butylamide system is quite pronounced, but in many cases potentiometric measurements were difficult due to precipitation of the salts formed. The neutralization of triphenylmethane produces an intense reddish orange color, which could be used as an indicator in visual titrations of weak acids with the n-butylamides.

ChemInform Abstract: TRILITHIUM SODIUM AMIDE (LI3NA(NH2)4), A COMPOUND WITH A STRUCTURE RELATED TO LITHIUM AMIDE

1982 ◽  
Vol 13 (44) ◽  
Author(s):  
H. JACOBS ◽  
B. HARBRECHT
Keyword(s):  
Lithium Amide ◽  
Sodium Amide

Mixed aggregates: crystal structures of a lithium ketone enolate/lithium amide and of a sodium ester enolate/sodium amide

1990 ◽  
Vol 112 (23) ◽  
pp. 8602-8604 ◽  
Author(s):  
Paul G. Williard ◽  
Mark J. Hintze
Keyword(s):  
Crystal Structures ◽  
Lithium Amide ◽  
Mixed Aggregates ◽  
Ester Enolate ◽  
Sodium Amide

Fine Structure of Platelet Interaction with a New Microcrystalline Collagen Preparation

1974 ◽  
Vol 32 ◽  
pp. 58-59
Author(s):  
W. H. Zucker ◽  
R. G. Mason
Keyword(s):  
Fine Structure ◽  
Platelet Aggregation ◽  
Hydrochloric Acid ◽  
Whole Blood ◽  
Platelet Adhesion ◽  
Hemostatic Agent ◽  
Native Collagen ◽  
Fibrillar Morphology ◽  
Clinical Interest ◽  
New Form

Platelet adhesion initiates platelet aggregation and is an important component of the hemostatic process. Since the development of a new form of collagen as a topical hemostatic agent is of both basic and clinical interest, an ultrastructural and hematologic study of the interaction of platelets with the microcrystalline collagen preparation was undertaken.In this study, whole blood anticoagulated with EDTA was used in order to inhibit aggregation and permit study of platelet adhesion to collagen as an isolated event. The microcrystalline collagen was prepared from bovine dermal corium; milling was with sharp blades. The preparation consists of partial hydrochloric acid amine collagen salts and retains much of the fibrillar morphology of native collagen.

Conformation of eukaryotic ribosomal RNAs

1983 ◽  
Vol 41 ◽  
pp. 592-593
Author(s):  
M. Boublik ◽  
G. Thornton ◽  
G. Oostergetel ◽  
J.F. Hainfeld ◽  
J.S. Wall
Keyword(s):  
Molecular Weight ◽  
Mass Measurement ◽  
Carbon Film ◽  
Structural Complexity ◽  
Scanning Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Pure Nitrogen ◽  
Freeze Dried ◽  
Scanning Transmission ◽  
Partially Unfolded

Understanding the structural complexity of ribosomes and their role in protein synthesis requires knowledge of the conformation of their components - rRNAs and proteins. Application of dedicated scanning transmission electron microscope (STEM), electrical discharge of the support carbon film in an atmosphere of pure nitrogen, and determination of the molecular weight of individual rRNAs enabled us to obtain high resolution electron microscopic images of unstained freeze-dried rRNA molecules from BHK cells in a form suitable for evaluation of their 3-D structure. Preliminary values for the molecular weight of 28S RNA from the large and 18S RNA from the small ribosomal subunits as obtained by mass measurement were 1.84 x 106 and 0.97 x 106, respectively. Conformation of rRNAs consists, in general, of alternating segments of intramolecular hairpin stems and single stranded loops in a proportion which depends on their ionic environment, the Mg++ concentration in particular. Molecules of 28S RNA (Fig. 1) and 18S RNA (not shown) obtained by freeze-drying from a solution of 60 mM NH+4 acetate and 2 mM Mg++ acetate, pH 7, appear as partially unfolded coils with compact cores suggesting a high degree of ordered secondary structure.

Improving soil remediation through characterization

1995 ◽  
Vol 53 ◽  
pp. 386-387
Author(s):  
E. C. Buck ◽  
N. L. Dietz ◽  
J. K. Bates
Keyword(s):  
Dust Particles ◽  
Radiochemical Analysis ◽  
Solid Product ◽  
Uranium Contamination ◽  
Physical Separation ◽  
X Ray ◽  
Rocky Flats ◽  
Remediation Strategies ◽  
Bearing Materials ◽  
X Ray Absorption

Operations at former weapons processing facilities in the U. S. have resulted in a large volume of radionuclidecontaminated soils and residues. In an effort to improve remediation strategies and meet environmental regulations, radionuclide-bearing particles in contaminant soils from Fernald in Ohio and the Rocky Flats Plant (RFP) in Colorado have been characterized by electron microscopy. The object of these studies was to determine the form of the contaminant radionuclide, so that it properties could be established [1]. Physical separation and radiochemical analysis determined that uranium contamination at Fernald was not present exclusively in any one size/density fraction [2]. The uranium-contamination resulted from aqueous and solid product spills, air-borne dust particles, and from the operation of an incinerator on site. At RFP the contamination was from the incineration of Pu-bearing materials. Further analysis by x-ray absorption spectroscopy indicated that the majority of the uranium was in the 6+ oxidation state [3].

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