Urea-phosphoric acid

Mixed with additives, urea is used in soHd fertilizers of various formulations, eg, urea—ammonium phosphate (UAP), urea—ammonium sulfate (UAS), and urea—phosphate (urea + phosphoric acid). Concentrated solutions of urea and ammonium nitrate (UAN) solutions (80—85 wt%) have a high nitrogen content but low crystallization point, suitable for easy transportation, pipeline distribution, and direct spray appHcation. 

Urea—Phosphate Type. Phosphoric acid imparts flame resistance to ceUulose (16,17), but acid degradation accompanies this process. This degradation can be minimized by iacorporation of urea [57-13-6]. Ph osph oryl a ting agents for ceUulose iaclude ammonium phosphate [7783-28-0] urea—phosphoric acid, phosphoms trichloride [7719-12-2] and oxychloride [10025-87-3] monophenyl phosphate [701-64-4] phosphoms pentoxide [1314-56-3] and the chlorides of partiaUy esterified phosphoric acids (see Cellulose esters, inorganic). 

Fig. 16 The migration of the proton along an O-H- - O bond in a co-crystal urea-phosphoric acid (1 1), as the temperature is increased from 150 K (top) to 335 K (bottom), becoming essentially centred (neutron study) [55]... 

Morrison CA, Siddick MM, Camp PJ, Wilson CC (2005) Toward understanding mobile proton behavior from first principles calculation the short hydrogen bond in crystalline urea-phosphoric acid. J Am Chem Soc 127 4042 048... 

A special type of pseudo-polymorphism is that related to the proton transfer along an X-H Y interaction. The motion may not be associated with a phase transition, but may well imply the transformation of a molecular crystal into a molecular salt. Wilson [34] has discussed, on the basis of an elegant neutron diffraction study, the migration of the proton along an O-H O bond in a co-crystal urea-phosphoric acid (1 1) whereby the proton migrates towards the mid-point of the hydrogen bond as the temperature is increased, becoming essentially centred at T > 300 K. Wiechert and Mootz [35] isolated two crystalline materials composed of pyridine and formic acid of different composition. In the 1 1 co-crystal the formic acid molecule retains its proton and transfer to the basic N-atom on the... 

Fig. 7.1. Hydrogen bonding in urea-phosphoric acid, [HjPOJ [(NH COH]+. The standard deviations for bond distances and angles are 0.005 A and 0.5° [405]...

Kostansek EC, Busing WR (1972) A single-crystal neutron-diffraction study of urea-phosphoric acid. Acta Cryst B28 2454-2459... 

It s well known that materials made of wood like a veneer, a chip board, a fiber board etc. are treated with phosphorus and nitrogen such as ammonium phosphate, urea-phosphoric acid mixture, dicyandiamide-phosphoric acid mixture and other phosphoric amines or amides to improve their fire resistance. They form a carbonized layer acceleratively on cellulose materials which gives them superior fire endurance. Ishihara and Kobayashi improved the fire endurance of wood by coating . ... 

Methyl ethers of D-fructose, difficult to estimate by any other means (especially those having the hydroxyl groups at C-1 and C-3 methylated), have been estimated by the alkaline 3,5-dinitrosalicylic acid reagent proposed by Bell and coworkers, and differentiation of the conformation of these methyl ethers was made possible by the addition of borate to the urea-phosphoric acid spray of Dedonder. 

Table 10.12. NPK Acid Solutions From UAN Solution, Urea, Phosphoric Acid, and Potash (10]... 

Carbamide kar-bo- d, kar- ba-mod [ISV carh- + amide] (1865) m See urea. Carbamide phosphoric acid (urea phosphoric acid) n. C0(NH2)2 H3P04. A catalyst for acid-setting resins. 

Carbamide Phosphoric Acid n (urea phosphoric acid) C0(NH2)2 H3P04. a catalyst for acid-setting resins. 

Phosphoric Acid-Based Systems for Cellulosics. Semidurable flame-retardant treatments for cotton (qv) or wood (qv) can be attained by phosphorylation of cellulose, preferably in the presence of a nitrogenous compound. Commercial leach-resistant flame-retardant treatments for wood have been developed based on a reaction product of phosphoric acid with urea—formaldehyde and dicyandiamide resins (59,60). 

Poly(vinyl nitrate) has been prepared and studied for use in explosives and rocket fuel (104,105). Poly(vinyl alcohol) and sulfur trioxide react to produce poly(vinyl sulfate) (106—111). Poly(vinyl alkane sulfonate)s have been prepared from poly(vinyl alcohol) and alkanesulfonyl chlorides (112—114). In the presence of urea, poly(vinyl alcohol) and phosphoms pentoxide (115) or phosphoric acid (116,117) yield poly(vinyl phosphate)s. 

The elemental and vitamin compositions of some representative yeasts are Hsted in Table 1. The principal carbon and energy sources for yeasts are carbohydrates (usually sugars), alcohols, and organic acids, as weU as a few other specific hydrocarbons. Nitrogen is usually suppHed as ammonia, urea, amino acids or oligopeptides. The main essential mineral elements are phosphoms (suppHed as phosphoric acid), and potassium, with smaller amounts of magnesium and trace amounts of copper, zinc, and iron. These requirements are characteristic of all yeasts. The vitamin requirements, however, differ among species. Eor laboratory and many industrial cultures, a commercial yeast extract contains all the required nutrients (see also Mineral nutrients). 

Chemical Processing. Activated carbon consumption in a variety of chemical processing appHcations is about 8% of the total (74). The activated carbon removes impurities to achieve high quaHty. For example, organic contaminants are removed from solution in the production of alum, soda ash, and potassium hydroxide (82). Other apphcations include the manufacture of dyestuffs, glycols, amines, organic acids, urea, hydrochloric acid, and phosphoric acid (83). 

CP esters are generally prepared as the ammonium salt [9038-38-4] by the reaction of cellulose with phosphoric acid and urea at elevated temperatures (130—150°C). The effects of temperature and urea/H PO /cellulose composition on product analysis have been investigated (33). One of the first commercially feasible dameproofing procedures for cotton fabric, the Ban-Flame process (34,35), was based on this chemistry. It consists of mixing cellulose with a mixture of 50% urea, 18% H PO, and 32% water. It is then pressed to remove excess solution, heated to 150—175°C for 5—30 minutes, and thoroughly washed (36). 

Evaporators have performed successfully in a number of industrial applications. Typical materials that are processed in evaporators include Caustic Soda, Caustic Potash, Sodium Carbonate, Sodium Dichromate, Sodium Nitrate, Ammonium Nitrate, Phosphoric Acid Superacid, Potash, Urea, Glue, Glycerine,... 

Aminotrimethanephosphonic acid is formed from formamide, acetamide, urea, or alkanenitriles with phosphorous acid [296]. By reaction of monoalkyl phosphite or P406 with glacial acetic acid or the corresponding anhydride ethane-1 -hydroxy-1,1-diphosphonic acid is formed after hydrolysis [297,298]. P406 can be obtained from P4 and 02 in a high yield of 85-90% [299]. 

An alternative sequence utilized 2-oxazolidone, which was readily synthesized from urea and ethanolamine, as the glycine equivalent. Subsequent treatment with phosphorous acid and formaldehyde produced iV-phosphonomethyl-2-oxazolidone 12 (16). Upon hydrolysis, and loss of CO2,12 provided the related derivative, iV-phosphonomethylethanolamine 13, which was oxidized at high temperature with a variety of metal catalysts including cadmium oxide (16) or Raney copper (17) to give GLYH3, after acidification. A similar oxidation route has also been reported starting from iV-phosphonomethy 1-morpholine (18). 

The phthalide 25, obtainable by condensation of 4,4 -bisdimethyl-aminobenzophenone-2-carboxylic acid with 3-dimethylaminoacetanilide and subsequent hydrolysis, was diazotized in sulfuric acid and the resultant diazonium salt treated with copper powder to yield 26. However, better yields are reportedly obtained by carrying out ring closure of the diazonium salt in phosphoric acid.103 A further synthetic route has also been described in which phthalides undergo intramolecular cyclization in the presence of aluminum chloride and urea.104,105 Thus, Crystal Violet lactone (2) has been directly converted into phthalide 26.106... 

An acidic-cure catalyst is added to the urea-formaldehyde resin before it is used as an adhesive. Ammonium chloride and ammonium sulfate are the most widely used catalysts for resins in the forest products industry. A variety of other chemicals can be used as a catalyst, including formic acid, boric acid, phosphoric acid, oxalic acid, and acid salts of hexamethylenetetramine. 

Calcium superphosphate, Lignin, Phosphoric acid, Urea Dobreva, Ts. et al., Chem. Abs., 1988, 109, 37213... 

Compound 98 reacts with carbon disulfide in the presence of an alkali solution to give 3 -mercapto-l,2,4-triazolo[4, 5 l,5][l,2,4]triazolo[3,4-A]benzothiazole 247. Treatment of product 98 with urea at 200°C for 4h affords 3 -hydroxy-l,2,4-triazolo[4, 5 l,5]-l,2,4-triazolo[3,4-A benzothiazole 99 (Scheme 20). Finally, the addition of concentrated phosphoric acid in the presence of sodium nitrite to compound 98 produces 1,2,3,4-tetra-zolo[l, 5 l,5]-l,2,4-triazolo[3,4- ]benzothiazole 248, and refluxing substituted benzaldehydes in acetic acid provides an easy access to 3 -aryl-l,2,4-triazolo[4, 5 l,5]-l,2,4-triazolo[3,4-A benzothiazoles 249 (Scheme 20) (Table 50) <2005IJC(B)625>. 

According to the literature [3,17,33], the heterogeneous nature of fertilizer production plants precludes the possibility of presenting a typical case study of such a facility. Nevertheless, the wastewater flows, the characteristics, and the treatment systems for a phosphoric acid and N-P-K fertilizer plant were parts of a large fertilizer manufacturing facility. The full facility additionally included an ammonia plant, a urea plant, a sulfuric acid plant, and a nitric acid plant. The typical effluent flows were 183 m /hour (806 gpm) from the phosphoric plant and 4.4 m /hour (20 gpm) from the water treatment plant associated with it, whereas in the N-P-K plant they were 420 m /hour (1850 gpm) from the barometric condenser and 108 m /hour (476 gpm) from other effluent sources. 

As a true testament to the potential long-term impact of H-bonding activation, a number of ureas, thioureas, and acid catalysts are now finding broad application in a large number of classical and modem carbon-carbon bond-forming processes. On one hand, Johnston s chiral amidinium ion 28 was elegantly applied to the asymmetric aza-Henry reactions (Scheme 11.12d). On the other hand, chiral phosphoric acids (e.g., 29 and 30), initially developed by Akiyama and Terada, have been successfully employed in Mannich reactions, hydrophosphonylation reac-tions, aza-Friedel-Crafts alkylations (Scheme 11.12e), and in the first example... 

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