Primary ammonium phosphate

Synonyms ammonium dihydrogen phosphate ammonium hiphosphate primary ammonium phosphate... 

The primary ammonium phosphate, NH4HaP04, forms tetragonal crystals.12 Its density is given as 1-758,13 1-779,14 and 1-803 15 at 19° C. 

In a very early study Patat (1945) investigated the hydrolysis of aniline to phenol in a water-based acidic solution in near-critical and supercritical water (Tc = 374.2°C, Pc = 220.5 bar). Phosphoric acid and its salts are used as the catalyst for this reaction. The reaction proceeds extremely slowly under normal conditions and reaches equilibrium at low conversion levels. For these reasons, Patat chooses to study the reaction in supercritical water to temperatures of 450°C and to pressures of 700 bar in a flow reactor. He finds that the reaction follows known, regular kinetics in the entire temperature and pressure space studied and the activation energy of the hydrolysis (approximately 40 kcal/mol) is the same in the supercritical as well as in the subcritical water. He suggests that the reaction is catalyzed by hydrogen ions formed from dissolution of phosphoric acid in supercritical steam. Very small amounts of phosphoric acid and the salts of the phosphoric acid are dissolved in the supercritical steam and are split into ions. Patat lists several dissolution constants for primary ammonium phosphates in supercritical steam. In this instance, the reaction performance is improved when the reaction is operated homogeneously in the mixture critical region and, thus, in intimate contact between the reactants and the catalyst. 

MAP Monoammonium phosphate Primary ammonium phosphate Empihcai H6NO4P Formuia NH4H2PO4... 

Primary ammonium phosphate. See Ammonium phosphate Primary amyl acetate. See Amyl acetate Primary amyl alcohol. See n-Amyl alcohol Primary decyl alcohol. See Decyl alcohol Primary isoamyl alcohol. See Isoamyl alcohol Primary magnesium phosphate. See Magnesium phosphate monobasic Primary octyl alcohol. See Caprylic alcohol Primary sodium phosphate. See Sodium phosphate... 

Production of nitric phosphates is not expected to expand rapidly ia the near future because the primary phosphate exporters, especially ia North Africa and the United States, have moved to ship upgraded materials, wet-process acid, and ammonium phosphates, ia preference to phosphate rock. The abundant supply of these materials should keep suppHers ia a strong competitive position for at least the short-range future. Moreover, the developiag countries, where nitric phosphates would seem to be appealing for most crops except rice, have already strongly committed to production of urea, a material that blends compatibly with sulfur-based phosphates but not with nitrates. 

Steam granulation is practiced in Europe, AustraUa, and elsewhere, chiefly in small plants in which superphosphate, either ordinary or triple, is a primary ingredient. However, for many of the larger operations, superphosphates have been replaced by ammonium phosphates as the principal P2 s source, and granulation procedures involving chemical reactions are employed in Europe as well as in the United States. 

Some commonly used primary nutrient fertilizers are incidentally also rich sources of calcium. Ordinary superphosphate contains monocalcium phosphate and gypsum in amounts equivalent to all of the calcium originally present in the phosphate rock. Triple superphosphate contains soluble monocalcium phosphate equivalent to essentially all the P2 5 product. Other fertilizers rich in calcium are calcium nitrate [10124-37-5] calcium ammonium nitrate [39368-85-9] and calcium cyanamide [156-62-7]. The popular ammonium phosphate-based fertilizers are essentially devoid of calcium, but, in view of the natural calcium content of soils, this does not appear to be a problem. 

Nomenclature. Because the ammonium phosphate fertilizers contain two of the primary plant nutrients, il is pertinent at tilts point lo briefly continent on the manner in which these fertilizers are named. A series of three numbers, separated by dashes, is used lo indicate the primary nutrient content uf fertilizer mixtures. In order, from left lo right, the numbers show the percentage of nitrogen, phosphoric oxide, and potash ... 

World ammonia capacity increased by nearly 14% from 1984 to 1996 while capacity for urea, the primary downstream nitrogen product, increased by 45%. The increases were due primarily to 1) a desire by some major importing countries to become more self-sufficient and 2) the construction of export-oriented capacity in the Middle East and in the former Soviet Union (prior to its breakup). Ammonium phosphate capacity increased by 9% between 1984 and 1996. Ammonium nitrate capacity declined by 2% from 1984 to 1996 while ammonium sulfate capacity declined by 8%35. 

Sulphate Sulphonate Ether sulphate Ether phosphate Ether carboxylate Carboxylate Primary ammonium Secondary ammonium Tertiary ammonium Quaternary ammonium Amine oxide Betaine... 

Nitric Phosphate. Fertilizers that are referred to as nitric phosphate or nitrophos-phate are produced by acidulation of phosphate rock with nitric acid or with mixtures of nitric and sulfuric or phosphoric acids. The primary advantage of nitric phosphate processes is that no sulfur or less sulfur is required as compared with superphosphates or ammonium phosphates this is particularly important during a shortage of sulfur, or in locations where sulfur must be shipped long distances. A variety of processes and equipment have been used in Europe since the late 1930s.3,12 Also there are a number of plants in Central and South America and in Asia. The production of nitric phosphates is complex. Simple substitution of nitric acid in a superphosphate-type acid-rock reaction is not feasible because (1) decomposition of the nitric acid would occur and cause noxious fumes and loss of nitrogen and (2) the product would be extremely hygroscopic and unstable. 

On evaporation of a solution containing ammonia and hypophos-phoric acid in equimolecular proportions, primary ammonium hypo-phosphate, NH4H3P206, crystallizes out.4... 

The ordinary salt, secondary ammonium phosphate, (NH4)2HP04, is prepared by concentrating a solution of phosphoric acid with addition of sufficient ammonia to prevent the development of an acidic reaction. It forms monoclinic crystals,8 of density 1-6199 or 1-678.10 It readily loses ammonia, with formation of the primary phosphate, the decomposition being rapid at 166° C.11 Above this temperature the primary phosphate is transformed into pyrophosphate. The aqueous solution of the secondary phosphate has a strongly alkaline reaction, and is decomposed by boiling, with evolution of ammonia and formation of the primary salt. 

Internal standards are prepared from reagent-grade mixtures of potassium dihydrogen phosphate and ammonium sulfate primary standards . Both primary standards are cross-checked with NIST 194 ammonium phosphate to verify the N and P2O5 grade and NIST 193 potassium nitrate to verify the... 

Iron phosphate coatings are amorphous coatings and very thin (0.1-lgm ). The working solution contains primary sodium or ammonium phosphates, together with other ingredients which may include an oxidizing accelerator, and surfactants to combine degreasing with the chemical treatment. The pretreatments operate between pH 3 and 5.5 at temperatures... 

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