Ammonia physical constants

According to H. Debray, between 1860-70, H. V. Regnault measured the physical constants of liquid ammonia, but the results were lost during the 1870 Franco-Prussian war. H. Debray waxes indignant ... 

Mode of synthesis A. cyanohydrin, by way of 2-nmino-2-deoxy-aldonic acid B. scission of sugar derivative epoxide with ammonia C. interconversion of hexosamine series D. hemihydrogenation of a-amino nitrile466 E. rearrangement of ketosyl-amine F. Removal of last carbon atom of hexosamine G. Hydrazinolysis (with inversion) of 2-0-tosyl-pentose. 6 Physical constants taken from this reference. c Derivatives (only) isolated. 

Ethyl dichlorophosphite is a colorless liquid, with an irritating odor. It fumes when exposed to air. It has the following physical constants sp. gr., 1.30526 b.p., 117.5° n °, 1.47176. It decomposes at 165° to ethyl chloride, phosphorus, phosphine, and phosphoric acid.3 It reacts with water to form hydrogen chloride and phosphorous acid, and with alcohols to form esters. When ammonia is passed through ethyl dichlorophosphite, ethyl phospheni-midate (ethoxyphosphimide), C2H5OP=NH, is formed. 

We define quantitative scientific knowledge as the combination of numerical data and formulas. A quantity can be a geometrical quantity like area or volume, or a physical quantity like mass or viscosity. A geometrical quantity is a variable which depends on the geometrical shape under consideration. Physical quantities can be categorised into constant properties and variables. Physical constants are the universal constants of nature, such as Boltzmann s constant (k = 1.380658 10-23/A-1). Physical properties are quantities which hold different values for different substances (or elements) in different states, for example, the Critical Volume (m3 mo/-1) 72.5 10-6 of Ammonia. The physical constants and physical properties are held in a database. Physical variables (sometimes called state variables) are independent variables which describe the state of a physical system, such as temperature (T) or pressure (P). The variables (including geometric values) are either specified by a user or computed by the system. 

In the amination of aliphatic halides, it is comparatively easy to replace the halogen by the amino group. The alkyl chlorides are readily converted to the corresponding amines by treatment with aqueous ammonia under pressure. The primary, secondary, and tertiary amines thus formed can be separated by taking advantage of slight differences in their physical constants or chemical reactivity. 

It is equivalent to say that entropy of vaporization is a constant value for non-associating Hquids. Associating Hquids, eg, ammonia, water, methanol, and ethanol, do not obey the rule of Pictet and Trouton. Despite its simplicity, the Pictet-Trouton view of Hquid vaporization (19) is an exceUent example of the many rules of thumb that have been useful aids in engineering calculations for decades (5,7,8,9,21). However, proper appHcation requires an understanding of the physical reasoning behind each rule. 

Chemical/Physical. The estimated hydrolysis half-life of acetonitrile at 25 °C and pH 7 is >150,000 yr (Ellington et al., 1988). No measurable hydrolysis was observed at 85 °C at pH values 3.26 and 6.99. At 66.0 °C (pH 10.42) and 85.5 °C (pH 10.13), the hydrolysis half-lives based on first-order rate constants were 32.2 and 5.5 d, respectively (Ellington et al., 1987). The presence of hydroxide or hydronium ions facilitates hydrolysis transforming acetonitrile to the intermediate acetamide which undergoes hydrolysis forming acetic acid and ammonia (Kollig, 1993). Acetic acid and ammonia formed react quickly forming ammonium acetate. 

Constitution XV for sucrose has up to the present satisfied all demands made upon it. Like its precursors, I and II (page 6), it was not incompatible with physical properties of sucrose such as the magnetic rotation, or the parachor, although the latter claim has been denied. Von Lippmann lists a great many early determinations of the physical properties of the sugar more recent measurements include the heat of combustion, the molecular weight in liquid ammonia, and various optical and electrical constants. ... 

Physical properties of the solvent are used to describe polarity scales. These include both bulk properties, such as dielectric constant (relative permittivity), refractive index, latent heat of fusion, and vaporization, and molecular properties, such as dipole moment. A second set of polarity assessments has used measures of the chemical interactions between solvents and convenient reference solutes (see table 3.2). Polarity is a subjective phenomenon. (To a synthetic organic chemist, dichloromethane may be a polar solvent, whereas to an inorganic chemist, who is used to water, liquid ammonia, and concentrated sulfuric acid, dichloromethane has low polarity.)... 

Physical chemical studies of dilute alkali metal-ammonia solutions indicate the principal solution species as the ammoniated metal cation M+, the ammoniated electron e , the "monomer M, the "dimer" M2 and the "metal anion" M. Most data suggest that M, M2, and M are simple electrostatic assemblies of ammoniated cations and ammoniated electrons The reaction, e + NH3 - lf 2 H2 + NH2 is reversible, and the directly measured equilibrium constant agrees fairly well with that estimated from other thermodynamic data. Kinetic data for the reaction of ethanol with sodium and for various metal-ammonia-alcohol reductions of aromatic compounds suggest that steady-state concentrations of ammonium ion are established. Ethanol-sodium reaction data allow estimation of an upper limit for the rate constant of e + NH4+ 7, H2 + NH3. 

Fig. 20. The real part of the microwave frequency (10 GHz) dielectric constant as a function of sodium metal concentration at 298 K in sodium-ammonia solutions. Note the break in the ordinate. [Adapted from Mahaffey and Jerde (117) used with permission from the American Physical Society, Reviews of Modern Physics.]...

A solvothermal process is one in which a material is either recrystallized or chemically synthesized from solution in a sealed container above ambient temperature and pressure. The recrystallization process was discussed in Section 1.5.1. In the present chapter we consider synthesis. The first solvothermal syntheses were carried out by Robert Wilhelm Bunsen (1811-1899) in 1839 at the University of Marburg. Bunsen grew barium carbonate and strontium carbonate at temperatures above 200°C and pressures above 100 bar (Laudise, 1987). In 1845, C. E. Shafhautl observed tiny quartz crystals upon transformation of freshly precipitated silicic acid in a Papin s digester or pressure cooker (Rabenau, 1985). Often, the name solvothermal is replaced with a term to more closely refer to the solvent used. For example, solvothermal becomes hydrothermal if an aqueous solution is used as the solvent, or ammothermal if ammonia is used. In extreme cases, solvothermal synthesis takes place at or over the supercritical point of the solvent. But in most cases, the pressures and temperatures are in the subcritical realm, where the physical properties of the solvent (e.g., density, viscosity, dielectric constant) can be controlled as a function of temperature and pressure. By far, most syntheses have taken place in the subcritical realm of water. Therefore, we focus our discussion of the materials synthesis on the hydrothermal process. 

Ammonia possesses similar physical properties to that of water, which is similarly highly associated. It is a good solvent for many compounds. Owing to the lower dielectric constant (NH3 16.9, H2O 78.3 at 298 K) of ammonia in comparison with water, less polar compounds are more soluble in ammonia and polar compounds, for example, salts, are more soluble in water. Organic compounds tend to have a higher solubihty in ammonia than in water. Armnonium salts, nitrates, nitrites, cyanides, and thiocyanates dissolve readily in ammonia. The solubihty increases from fluorides to chlorides, bromides, and iodides. Salts with higher charged ions dissolve only poorly in ammonia. This results in the reversal of some precipitation reactions in ammonia compared to water. 

The most important physical property of a solvent is its polarity. Molecules with large dipole moments such as water and ammonia form polar solvents. The macroscopic manifestation is the dielectric constant (sr), the factor by which electrostatic forces are weakened in comparison with... 

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