Sodium ammonia solutions, absorption

The monomer species, M, has been described by Kraus (31) as an ion pair. Although he did not elaborate on its possible structure, one may assume that he pictured this species as two ammoniated ions held together by electrostatic forces. Douthit and Dye (12) pointed out that such a picture is consistent with the absorption spectra of sodium-ammonia solutions. Becker, Lindquist, and Alder (2) proposed an expanded metal model in which an electron was assumed to circulate in an expanded orbital on the protons of the coordinated ammonia molecules of an M + ion. The latter model is difficult to reconcile with optical, volumetric, and NMR data (16). 

Figure 1. Absorption spectrum in dilute sodium-ammonia solution (concentration 5 X 10" M) (Reference 25).

Tail gas scmbbers are sometimes used on single absorption plants to meet S02 emission requirements, most frequently as an add-on to an existing plant, rather than on a new plant. Ammonia (qv) scrubbing is most popular, but to achieve good economics the ammonia value must be recovered as a usable product, typically ammonium sulfate for fertilizer use. A number of other tail gas scrubbing processes are available, including use of hydrogen peroxide, sodium hydroxide, lime and soda ash. Other tail gas processes include active carbon for wet oxidation of S02, molecular sieve adsorbents (see MoLECULARSIEVEs), and the absorption and subsequent release of S02 from a sodium bisulfite solution. 

The spectra of dilute solutions of lithium, sodium, potassium, calcium, and barium in liquid deutero-ammonia indicate that the absorbing species is the same in each case. The dependence of the shape, intensity, and energy of the absorption band on temperature was investigated for sodium-ND3 solutions. The data are discussed in terms of the electron-in-a-cavity model. No spectral evidence was found for the presence of new species in ND3 solutions containing mixtures of sodium and sodium iodide. 

Cognate preparations. Cyclohexa-2,5-dienecarboxylic acid (1,4-dihydroben-zoic acid).17a A solution of benzoic acid (10g, 0.082 mol) in ethanol (100 ml) and liquid ammonia (600 ml) is stirred and sodium (6.2g, 0.27g-atom) added in small pieces, followed by ammonium chloride (14.6 g, 0.27 mol). The ammonia is evaporated and the residual material dissolved in ice-water (500 ml). After acidification with 10 per cent hydrochloric acid the solution is extracted with four 100 ml portions of ether, the ether washed once with saturated sodium chloride solution, dried over magnesium sulphate and concentrated in vacuo. The remaining pale yellow oil is distilled at 96-98 °C (0.01 mmHg) to give 9.0 g (89%) of 1,4-dihydrobenzoic acid this product shows no u.v. absorption above 220 nm. 

The formulas given in Table 1 are based solely on weight uptake data after exposure of the polyacetylene films to metal-ammonia solutions followed by washing and vacuum drying. To determine the actual metal content of the doped polymers atomic absorption measurements were carried out. These show conclusively that ammonia molecules are coinserted in the polyacetylene films along with the metal cations. This can be compared to the coinsertion of the solvent tetrahydrofuran which has been found to coordinate with the alkali metal ions Li and Na (22,23). The sodium doped samples coinsert slightly more than about one ammonia molecule for each sodium ion. The real formula for the sodium... 

Dilute an aliquot of a 0 1 N hydrochloric acid solution of morphine, containing not more than 1 mg of morphine, to 20 ml with 0 1 N hydrochloric acid in a 50-ml graduated flask, add 8 ml of freshly prepared, 1 per cent sodium nitrite solution and mix well. After exactly fifteen minutes add 12 ml of dilute ammonia solution, dilute to volume and remix. Measure the extinction at the absorption maximum at about 442 mfJL, using 4-cm cells, with, in the comparison cell, a solution prepared exactly as above but substituting 20 ml of 0-1N hydrochloric acid for the sample solution. Read the morphine content from a standard curve prepared by carrying out the procedure on suitable volumes of a standard solution of morphine in OdN hydrochloric acid, covering the range 0 to 1 mg of morphine. 

Recovery of Ammonia. The filter Hquor contains unreacted sodium chloride and substantially all the ammonia with which the brine was originally saturated. The ammonia may be fixed or free. Fixed ammonia (ammonium chloride [12125-02-97]) corresponds stoichiometrically to the precipitated sodium bicarbonate. Free ammonia includes salts such as ammonium hydroxide, bicarbonate, and carbonate, and the several possible carbon—ammonia compounds that decompose at moderate temperatures. A sulfide solution may be added to the filter Hquor for corrosion protection. The sulfide is distilled for eventual absorption by the brine in the absorber. As the filter Hquor enters the distiller, it is preheated by indirect contact with departing gases. The warmed Hquor enters the main coke, tile, or bubble cap-fiUed sections of the distiller where heat decomposes the free ammonium compounds and steam strips the ammonia and carbon dioxide from the solution. 

Test 1. Mix a quantity containing 40 mg of miconazole nitrate with 20 mL of a mixture of 1 volume of 1 M sulfuric acid and 4 volumes of methanol and shake with two 50 mL quantities of hexane, discarding the organic layers. Make the aqueous phase alkaline with 2 M ammonia and extract with two 40 mL quantities of chloroform. Combine the chloroform extracts, shake with 5 g of anhydrous sodium sulfate, filter, and dilute the filtrate to 100 mL with chloroform. Evaporate 50 mL to dryness and dissolve the residue in 50 mL of a mixture of 1 volume of 0.1 M hydrochloric acid and 9 volumes of methanol. The light absorption of the resulting solution, Appendix II B, in the range 230-350 nm exhibits maxima at 264, 272, and 282 nm. 

Chemo-Trenn A process for absorbing ammonia, carbon dioxide, hydrogen sulfide, and other undesirable gases from coal gas by absorption in a warm solution of a salt of a weak organic acid such as sodium cresylate. Invented by H. Bahr at I.G. Farbenindustrie, Germany, in 1938. 

A 1-1. three-necked flask is equipped with a mercury-sealed stirrer, an inlet tube, and a reflux condenser which is connected through a soda-lime tube to a gas-absorption trap.1 The apparatus is dried in an oven and assembled rapidly to exclude moisture it is advisable to set up the apparatus in a hood to vent ammonia which may escape by accident. The flask is cooled in a Dry Ice-trichloroethylene bath, and 200 ml. of anhydrous (refrigeration grade) ammonia is introduced through the inlet tube from an ammonia cylinder which is either inverted or equipped with a siphon tube. Just before the apparatus is assembled, 8.1 g. (0.35 gram atom) of sodium is cut, weighed, and kept under kerosene in a small beaker. The Dry Ice bath is removed, the inlet tube is replaced by a rubber stopper, and a crystal of hydrated ferric nitrate (about 0.2 g.) is added. A small (about 5-mm.) cube of the sodium is cut, blotted rapidly with filter paper, and added quickly to the liquid ammonia. The solution is stirred until the blue color disappears, after which the remainder of the sodium is added in narrow, thin strips about as rapidly as... 

Comparison of the electrical conductivities of chromium penta-phenyl hydroxide, sodium hydroxide and ammonia in absolute methyl alcohol and in methyl alcohol-water solution, shows that the former is a very strong base. In aqueous methyl alcohol solution the chromium compound does not appear to approach the limiting value with increasing dilution. The ultra-violet absorption spectrum examined in absolute ethyl alcohol solution resembles that of chromic acid and the dichromates, but the absorption is noticeably greater in the case of the organic compound. 

Unfortunately, liquid ammonia possesses a very intense absorption band at 15,320 A. (2 i and/or 2vz) so that this region is inaccessible for quantitative measurements even with a 1 mm. cell. If ND8 is used as the solvent instead of NH8, no intense overtone or combination bands of the solvent occur in the spectral region of interest (Figure 1). The spectra of dilute solutions of lithium, sodium, potassium, calcium, and barium in liquid ND8, and the perturbations arising from concentration changes, temperature changes, and the presence of inert salts have been investigated. 

The dependence of the shape, intensity, and energy of the absorption band on temperature was investigated using a 2.83 X 10 AM solution of sodium in liquid ND8. The spectrum of this solution at several temperatures is shown in Figure 6b. A plot of the energy of the absorption maximum vs. temperature is shown in Figure 7, and a least squares treatment of these data indicates that the temperature dependence of the band maximum is — 14.3/cm./deg. Values of —9.7/cm./deg. for sodium (6), —9.1/cm./deg. for potassium (2), and — 12.7/cm./deg. for the alkali metal solutions (9) in liquid ammonia have been reported. No detectable decomposition of the solution occurred during the four hours required to take the measurements between —69° and —31° C. The intensity of the band, as measured by both the absorbance (1.48 0.04)... 

The following route is described in US Patent 4,145,552 At ambient temperature, over a period of thirty minutes, a solution of 33.8g (O.lmol) of (-)-vincadiformine in a mixture of 140 ml of anhydrous dimethylformamide and 140 ml of anhydrous toluene is added to a suspension of 2.64 g (0.11 mol) of sodium hydride in a mixture of 200 ml of anhydrous tetrahydrofuran, 20 ml of anhydrous hexamethylphosphotriamide (EMPT) and 18.7 ml (0.14 mol) of trimethyl phosphite. When the release of hydrogen has finished (about two hours later), the solution is cooled to -10°C and then stirred under an oxygen atmosphere until absorption ceases (duration 3 hours). Still at -10°C, 136 ml of glacial acetic acid are added, and the mixture is then left at ambient temperature for two hours. After the addition of 500 ml of 1 N sulfuric acid, the aqueous phase is isolated, reextracted with 150 ml of isopropyl ether, made alkaline with 350 ml of 11 N ammonia, then extracted 3 times with 300 ml aliquots of methylene chloride. After drying over calcium... 

Absorption Abatement or extended absorption refers to modifications that involve the addition of increased absorption capacity or optimization of the existing absorption system to oxidize and react the nitrogen oxides with water to form acid.. Tail gases are passed through an absorber containing either water or an aqueous solution of ammonia, urea or sodium hydroxide. When water is used as the absorbent, the resultant weak acid is recycled. This increases nitric acid yields by 1% to 3%. When other absorbents are used, the recovered NOx is typically consumed in the production of nitrogen solutions for fertilizer use. If sodium hydroxide is the absorbent, pure sodium nitrite and sodium nitrate may be recovered91,104. 

Ammonia Heat 500 mg of sample with 5 mL of 1 N sodium hydroxide. The odor of ammonia is not perceptible. Chloride Heat 1 g of sample with 25 mL of water and 2 mL of nitric acid until the sample dissolves. Cool, dilute with water to 100 mL, and mix. Add 1 mL of silver nitrate TS to 10 mL of the solution. No turbidity immediately develops. Lead Determine as directed in the Flame Atomic Absorption Spectrophotometric Method under Lead Limit Test, Appendix IIIB, using a 1-g sample. 

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