Acid continued sulfamic

Sulfamic acid [5329-14-6] (amidosulfuric acid), HSO2NH2, molecular weight 97.09, is a monobasic, inorganic, dry acid and the monoamide of sulfuric acid. Sulfamic acid is produced and sold in the form of water-soluble crystals. This acid was known and prepared in laboratories for nearly a hundred years before it became a commercially available product. The first preparation of this acid occurred around 1836 (1). Later work resulted in identification and preparation of sulfamic acid in its pure form (2). In 1936, a practical process which became the basis for commercial preparation was developed (3,4). This process, involving the reaction of urea with sulfur trioxide and sulfuric acid, continues to be the main method for production of sulfamic acid. 

Nickel. Nickel plating continues to be very important. Many plating baths have been formulated, but most of the nickel plating is done in either Watts baths or sulfamate baths. Watts baths contain sulfate and chloride nickel salts along with boric acid, and were first proposed in 1916 (111). Nickel was first plated from sulfamate in 1938 (112) and patented in 1943 (108). The process was brought to market in 1950 (113). Typical bath compositions and conditions are shown in Table 14. 

Ref 10) and by fluorination of 1) cyanuric acid (Ref 5) 2) sulfamide, yield 45% (Ref 14) [Kelly and Sukornick found that sulfamic acid, w, and F will react continuously in a flow re-... 

Reliable analytical methods are available for determination of many volatile nitrosamines at concentrations of 0.1 to 10 ppb in a variety of environmental and biological samples. Most methods employ distillation, extraction, an optional cleanup step, concentration, and final separation by gas chromatography (GC). Use of the highly specific Thermal Energy Analyzer (TEA) as a GC detector affords simplification of sample handling and cleanup without sacrifice of selectivity or sensitivity. Mass spectrometry (MS) is usually employed to confirm the identity of nitrosamines. Utilization of the mass spectrometer s capability to provide quantitative data affords additional confirmatory evidence and quantitative confirmation should be a required criterion of environmental sample analysis. Artifactual formation of nitrosamines continues to be a problem, especially at low levels (0.1 to 1 ppb), and precautions must be taken, such as addition of sulfamic acid or other nitrosation inhibitors. The efficacy of measures for prevention of artifactual nitrosamine formation should be evaluated in each type of sample examined. 

In a 1.5-1. reaction flask provided with a reflux condenser and a drying tube filled with calcium chloride are placed 97 g. (1 mol) of dry pulverized sulfamic acid and 417 g. (2 mols) of dry pulverized phosphorus(V) chloride. The reactants are thoroughly mixed, and the flask is immersed in a steam bath. After about 20 minutes, hydrogen chloride gas begins to be evolved, and after a minimum of about 35 minutes the reaction mixture becomes liquid. Evolution of gas continues for at least 45 minutes when it has ceased, the flask is evacuated to a pressure of 20 mm. Hg and the phosphorus oxychloride (phosphoryl chloride), POCI3, formed during the reaction is distilled from the mixture at a bath temperature of 80°. 

Tip the 50-mL Erlenmeyer flask so that some mixing of the sulfamic acid solution with the solution inside the vial occurs. As gas evolution decreases, tip the Erlenmeyer flask more to achieve additional mixing. Continue to mix the solutions by gentle shaking and swirling of the flask until there is no further evolution of nitrogen gas. Then wait about 5 minutes to be certain that the contents of the flask have returned to room temperature. 

Yebra et al. [83] used a continuous-flow procedure for the indirect determination of sodium cyclamate by flame atomic absorption spectrometry (FAAS). This method is based on oxidation of the sulfamic group derived from cyclamate to sulfate in acidic conditions and in the presence of sodium nitrite. The procedure is adapted to a flow system with precipitate dissolution (Figure 24.11), where sulfate formed is continuously precipitated with lead ion. The lead sulfate formed is retained on a filter, washed with diluted ethanol, and dissolved in ammonium acetate (because of the formation of soluble lead acetate) for online FAAS determination of lead, the amount of which in the precipitate is proportional to that of cyclamate in the sample. In this work a home-made filtration device was used made of a Teflon tubing packed with a cotton pulp and the ends of the filter column were plugged with filter paper (chamber inner volume 141 J,L). This precipitate collector was effective in retaining the precipitate and did not produce excessive back-pressure if the precipitate was dissolved following each precipitation cycle. 

A soln. of 5 g. a-phenyl-a-methyl- -aminopropionic acid and NaBr (cf. S. Ueno and H. Sekiguchi, J. Soc. Ghem. Ind. Japan 37, 235B (1934) G. A. 28, 5368) in water acidified with H2SO4, heated to 80°, stirred and treated dropwise with aq. NaNOg, heating continued for 30 min., and excess nitrite decomposed with sulfamic acid 3.5 g. a-benzyllactic acid. E. Testa et al., A. 619, 4 1 (1958) cf. Synth. Meth. 15, 272. 

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