Аммоний сульфа

Описание

Ammonium sulfate was the first nitrogenous fertilizer made by the Haber-Bosch process, produced by the reaction of ammonia with sulfuric acid. In contrast with the nitrate salt, it is chemically stable, not highly hygroscopic. It also supplies supplemental sulfur to soils that may be deficient in this element, but this is of minor value when it is used on soils receiving applications of ordinary superphosphate.
The disadvantages of the material are its relatively low nitrogen content, which increases storage and transportation costs, and its marked tendency to cause soil acidification, which is greater than that of any other nitrogen fertilizer material.

Химические свойства

White crystalline powder

Физические свойства

White crystalline solid; orthorhombic crystal; density 1.769 g/cm³ at 20°C; melts between 511 to 515°C (in a closed system): however, in an open system, it melts with decomposition at 280°C; readily dissolves in water (solubility, 70.6 g and 104 g per 100 g water at 0°C and 100°C, respectively); insoluble in acetone, alcohol and ether.

Вхождение

Ammonium sulfate occurs in trace concentrations in the upper atmosphere. It is widely used as a fertilizer for rice and other crops. It is a source of sulfur for the soil. It is also used as an additive to supply nutrient nitrogen in fermentation processes (e.g., yeast production from molasses). It also is used for fireproofing timber and plastics, and in treatment of hides, and leather production.

Использование

Ammonium Sulfate is a dough conditioner, firming agent, and pro- cessing aid which is readily soluble in water with a solubility of approximately 70 g in 100 g of water at 0°c. the ph of a 0.1 molar solution in water is approximately 5.5. it is used in caramel produc- tion and as a source of nitrogen for yeast fermentation. in bakery products, up to 0.25 part per 100 parts by weight of flour is used.

Определение

ammonium sulphate: A whiterhombic solid, (NH₄)₂SO₄; r.d. 1.77;decomposes at 235°C. It is very solublein water and insoluble in ethanol.It occurs naturally as the mineralmascagnite. Ammonium sulphatewas formerly manufactured from the‘ammoniacal liquors’ produced duringcoal-gas manufacture but is nowproduced by the direct reaction betweenammonia gas and sulphuricacid. It is decomposed by heating torelease ammonia (and ammoniumhydrogensulphate) and eventuallywater, sulphur dioxide, and ammonia.Vast quantities of ammoniumsulphate are used as fertilizers.

Методы производства

Ammonium sulfate is a high-tonnage industrial chemical, but frequently may be considered a byproduct as well as intended end-product of manufacture. A significant commercial source of (NH4)2SO4 is its creation as a byproduct in the manufacture of caprolactam, which yields several tons of the compound per ton of caprolactam made. Ammonium sulfate also is a byproduct of coke oven operations where the excess NH3 formed is neutralized with H2SO4 to form (NH4)2SO4. In the Meresburg reaction, natural or byproduct gypsum is reacted with ammonium carbonate: CaSO4·2H2O + (NH4)2CO3 CaCO3 + (NH4)2SO4 +2 H2O The product is stable, free-flowing crystals. As a fertilizer, (NH4)2SO4 has the advantage of adding sulfur to the soil as well as nitrogen. By weight, the compound contains 21% N and 24% S. Ammonium sulfate also is used in electric dry cell batteries, as a soldering liquid, as a fire retardant for fabrics and other products, and as a source of certain ammonium chemicals.

Общее описание

White odorless solid. Sinks and dissolves in water.

Реакции воздуха и воды

Dissolves in water with evolution of some heat.

Профиль реактивности

Ammonium sulfate is acidic in aqueous solution. When a little Ammonium sulfate is added to fused potassium nitrite, a vigorous reaction occurs attended by flame [Mellor 2:702 1946-47].

Профиль безопасности

Moderately toxic by several routes. Human systemic effects by ingestion: hypermotility, diarrhea, nausea or vomiting. See also SULFATES. Incandescent reaction on heating with potassium chlorate. Reaction with sodmm hypochlorite gves the unstable explosive nitrogen trichloride. Incompatible with (K + NH4NO3), KNO2, (NaK + NH4NO3). When heated to decomposition it emits very toxic fumes of NOx, NH3, and SOx.

Методы очистки

Crystallise it twice from hot water containing 0.2% EDTA to remove metal ions, then finally from distilled water. Dry it in a desiccator for 2 weeks over Mg(ClO4)2. After 3 recrystallisations, ACS grade had Ti, K, Fe, Na at 11, 4.4, 4.4, 3.2 ppm respectively.