Sulfamic acid preparations

Nickel Sulfamate. Nickel sulfamate [13770-89-3] Ni(S02NH2)2 4H2O, commonly is used as an electrolyte ia nickel electroforming systems, where low stress deposits are required. As a crystalline entity for commercial purposes, nickel sulfamate never is isolated from its reaction mixture. It is prepared by the reaction of fine nickel powder or black nickel oxide with sulfamic acid ia hot water solution. Care must be exercised ia its preparation, and the reaction should be completed rapidly because sulfamic acid hydrolyzes readily to form sulfuric acid (57). 

Before a 1/1 /70 FDA ban (rescission proposed in early 1990), cyclamate noncaloric sweeteners were the major derivatives driving cycloliexylamine production. The cyclohexylsulfamic acid sodium salt (39) [139-05-9J and mote thermally stable calcium cyclohexylsulfamic acid (40) [139-06-1] salts were prepared from high purity cyclohexylamine by, among other routes, a reaction cycle with sulfamic acid. 

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. 

Sulfamic acid has a unique combination of properties that makes it particularly well suited for scale removal and chemical cleaning operations, the main commercial appHcations. Sulfamic acid is also used in sulfation reactions, pH adjustment, preparation of synthetic sweeteners (qv), and a variety of chemical processing appHcations. Salts of sulfamic acid are used in electroplating (qv) and electroforrning operations as well as for manufacturing flame retardants (qv) and weed and hnish killers (see Herbicides). 

Sulfation by sulfamic acid has been used ia the preparation of detergents from dodecyl, oleyl, and other higher alcohols. It is also used ia sulfating phenols and phenol—ethylene oxide condensation products. Secondary alcohols react ia the presence of an amide catalyst, eg, acetamide or urea (24). Pyridine has also been used. Tertiary alcohols do not react. Reactions with phenols yield phenyl ammonium sulfates. These reactions iaclude those of naphthols, cresol, anisole, anethole, pyrocatechol, and hydroquinone. Ammonium aryl sulfates are formed as iatermediates and sulfonates are formed by subsequent rearrangement (25,26). 

The A/-alkyl and W-cyclohexyl derivatives of sulfamic acid are comparatively stable. The A/-aryl derivatives are very unstable and can only be isolated ia the salt form. A series of thia2olylsulfamic acids has been prepared. 

The assay determination of sulfamic acid is made by titration of an accurately prepared sulfamic acid solution using sodium nitrite solution and an external potassium iodide starch-paste indicator. It is based on the reaction... 

Standard 1/10 N nitrite is used to titrate a solution prepared by dissolving 10—100 mg of sulfamic acid and about 6 mL of (1 + 1) H2SO4 in 300 mL of distilled water at 40—50°C. At the end point, the colorless external potassium iodide starch-paste indicator changes to blue. A 1-mL solution of 1/ION NaN02 is equivalent to 9.709 mg of sulfamic acid. The 1/10 N nitrite titrant solution is standardized using primary standard-grade sulfamic acid. For sulfamate assay determination, the same procedure is used as for sulfamic acid. 

Sulfation andSulfamation. Sulfamic acid can be regarded as an ammonia—SO. complex and has been used thus commercially, always in anhydrous systems. Sulfation of mono-, ie, primary and secondary, alcohols polyhydric alcohols unsaturated alcohols phenols and phenolethylene oxide condensation products has been performed with sulfamic acid (see Sulfonation and sulfation). The best-known appHcation of sulfamic acid for sulfamation is the preparation of sodium cyclohexylsulfamate [139-05-9] which is a synthetic sweetener (see Sweeteners). 

Sulfamation is the formation (245) of a nitrogen sulfur(VI) bond by the reaction of an amine and sulfur trioxide, or one of the many adduct forms of SO. Heating an amine with sulfamic acid is an alternative method. A practical example of sulfamation is the artificial sweetener sodium cyclohexylsulfamate [139-05-9] produced from the reaction of cyclohexylamine and sulfur trioxide (246,247) (see Sweeteners). Sulfamic acid is prepared from urea and oleum (248). Whereas sulfamation is not gready used commercially, sulfamic acid has various appHcations (see SuLFAMiC ACID AND SULFAMATES) (249—253). 

Imidodisulfuric acid derivatives can be prepared from urea by using less sulfuric acid than required for sulfamic acid (p. 741) warm... 

Major emphasis in studies of N-nitroso compounds in foods has been placed upon volatile nitrosamines, in part because these compounds are relatively easy to isolate from complex matrices by virtue of their volatility. Procedures utilizing atmospheric pressure or vacuum distillation have been used by most investigators, with variations of the method of Fine e al. (2) being among the most popular. This procedure employs vacuum distillation of a mineral oil suspension of the sample with optional addition of water to improve nitrosamine recovery from low moisture content samples (6) The usual approach to prevention of nitrosamine formation during analysis involves adding sulfamic acid or ascorbate to destroy residual nitrite at an early stage of sample preparation. 

Nickel sulfamate is prepared hy heating an aqueous solution of sulfamic acid, H2NSO3H, with fine nickel powder or black nickel oxide under controlled conditions ... 

At ordinary temperatures, sulfamic acid hydrolyzes slowly forming ammonium bisulfite. However, when heated it hydrolyzes rapidly forming sulfuric acid. Therefore nickel sulfamate should be prepared rapidly before any sulfamic acid hydrolysis occurs due to longer contact time with water. 

Preparation of polyamidic acid sulfamic acid derivatives... 

Thiazolyl sulfamic acids, rearrangement of sulfonic acid, 70 rearrangement to sulfonic acid, 75 by sulfonation, 75 2-Thiazolyl sulfenyl chloride, transformation to, thiazolyl disulfides. 412 2-Thiazolyl sulfide, in hydrocarbon synthesis, 406 oxidation of, with m-chloroperbenzoic acid, 415 with CrOj, 415 with Hj02,405,415 with KMn04,415 physical properties, infrared, 405 NMR, 404 pKa, 404 ultraviolet, 404 preparation of, from 2-halothiazoles and 5-Thiazolyl sulfides, bis-5-thiazolyl sulfide, oxidation of, 415 general, 418 5-(2-hydroxythiazolyl)phenyl sulfide case, 418 physical properties, 418 preparation of, 417-418 table of compounds, 493-496 uses of. 442 2-Thiazolyl sulfinic acid, decomposition of, 413 preparation of, from 2-acetamidothiazole sulfonyl chloride, 413 from A-4-thiazoline-2-thione and H, 0, 393,413 table of compounds, 472-473 5-Thiazolyl sulfinic add, preparation of,... 

Sample Preparation Transfer 50 g of sample, accurately weighed, into a 1000-mL distillation flask, and add 1.0 mL of 10% sulfamic acid, 1.0 mL of NDPA Standard Solution, 1.0 mL of 1 A hydrochloric acid, and 15 mL of water. Mix the contents by gently swirling, and let the flask stand in the dark for 10 min. Add 10.0 mL of 3 A potassium hydroxide and two small boiling chips, mix, and connect the flask to the distillation apparatus. 

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