Sulphamic acids

Both compounds are soluble in water and are readily hydrolysed to sulphamic acid, HjN S03" andammonia the hydrogen atoms are in each case replaceable by metals to form salts. Many derivatives of sulphamide and cyclic derivatives of sulphimide are known. 

The sulphuric acid may be replaced by 1-2 g. of sulphamic acid (NH,SOjH) or by p-toluenesulphonic acid (p-CHjCjH SOjH). 

In the second method of homogeneous precipitation, the precipitant itself is generated by a chemical reaction. For example, Ba + can be homogeneously precipitated as BaS04 by hydrolyzing sulphamic acid to produce S04 . 

Nitrohydrochloric acid Perchloric acid Phenosulphonic acid Phosphorus pentoxide Propionic acid Selenic acid Spent acids Sulphamic acid Sulphuric acid and oleum (fuming sulphuric acid) Sulphurous acid Thioglycolic acid Trichloroacetic acid... 

Sulfur and Sulfur Compounds, 123 Sulfur chloride, 123 Sulfur dioxide, 123 Sulfur hexafluoride, 123 Sulfur tetrafluoride, 124 Sulfur trioxide, 124 Sulfuric acid, 123 Sulfurous acid, 124 Sulfuryl fluoride, 124 Sulphamic acid, 124 Sulprofos, 124... 

Heat exchanger surfaces need to he kept clean. Aqueous circuits (evaporator or condenser) can he cleaned with a chemical such as sulphamic acid, brushed or subjected to high-pressure water jets. In each case, all traces of dirt and chemical need to be removed from the circuit before it is put back to work. In cases of doubt, the manufacturer s advice should be sought. A layer of scale 2 mm thick on a condenser tube can cause a power increase of 16%, and the need to clean a condenser can usually be deduced from the condensing pressure. Persons using high-pressure water jets should wear face masks to avoid inhaling aerosol droplets. 

Sulphates. Sulphate ion may be generated by the hydrolysis of aminosulphonic (sulphamic) acid ... 

The barium sulphate may be precipitated either by the use of sulphuric acid, or from homogeneous solution by the use of sulphamic acid solution which produces sulphate ions on boiling ... 

Procedure Precipitation from homogeneous solution (sulphamic acid method). The... 

No satisfactory direct gravimetric procedure is available but nitrite can be oxidised to nitrate by permanganate or cerium(IV) and then determined in that form. The determination of total nitrate + nitrite is an important analysis, e.g. for soil samples. Nitrite may be destroyed using urea, sulphamic acid or hydrazine sulphate the reaction with the former is ... 

A review of earlier results is included in a paper by Kiyoura and Urano [946] on the decompositions of (NH4)2S04 (413—513 K) and NH4HS04 (433-473 K). The intermediate formation at 433 K of the double salt (NH4)3H(S04)2 was detected by X-ray diffraction and this salt decomposed to NH4HS04 at 453 K. Decomposition of the ammonium hydrogen sulphate at 473 K proceeded through the formation of molten sulphamic acid... 

L. Peraldo-Bicelli, Proc. Symp. Sulphamic Acid, Eleciromet. AppL, Milan (1966) 19 B. E. Cain and N. Y. Kanda, Z. Kristallogr. Mineral., 135 (1972) 253-260. 

When hot sodium nitrate or nitrite is treated with sulphamic acid, violent detonations occur. 

The situation does not improve with mixtures with the hydrides of the elements. Thus, a detonation occurred during contact between water and chlorine due to an accidental spark. Phosphine, silane and diborane all combust spontaneously in chlorine (their behaviour is the same in oxygen). With hydrogenated nitrogenous compounds ammonia, hydrazine, hydroxylamine, ammonium salts (especially ammonium chloride), and also sulphamic acid (these last two in an acid medium) there is ignition or even detonation. 

Sulphamic acid No data No data R4 R R Mo data No data No data R R R Mo data No data... 

The use of sulphamic acid (12.1) has been recommended, resulting in a shift of pH from 1.8 to between 3.0 and 3.5 as the temperature approaches the boil, thus giving rise to less fibre damage. Typically, 6% o.w.f. sulphamic acid is added, together with an auxiliary and sodium sulphate. The change in pH arises as a result of hydrolysis of the sulphamic acid to give ammonium bisulphate (Scheme 12.1) [2,5]. 

Wong [10,11] has studied this in further detail and found that carrying out the titration at pH 2 yields a true concentration of total residual chlorine after correction for naturally occurring iodate. The effectiveness of sulfamic acid in this method for removal of the nitrite interference is shown in Fig. 4.1. In this experiment, all the solutions contained 30 pmol/1 nitrite, and about 0.5 pmol/1 of iodate. The absorbance of the solution at 353 nm decreased with increasing amounts of added sulphamic acid. A constant absorbance was recorded when 3 ml or more of 1% (w/v) sulphamic acid was added to the solution, and this absorbance was identical with that in a sample containing the same amount of iodate and no nitrite. A concentration of nitrite of 30 pmol/l is unlikely to occur in estuarine water and seawater ... 

Figure 4.1. Absorbance of tri-iodide at 353 nm formed from a fixed concentration of iodate in the presence of 30 xmol/l nitrite upon the addition of various volumes of 1% (w/v) sulphamic acid N denotes the case where neither nitrite nor sulphamic acid was present in the solution. From [8]...

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