Urea nitrate

Urea nitrate is prepared by treating urea with dilute nitric acid, e.g. 34%. Choisy [62] proposed using it as an explosive. However, the manufacture of cheap urea 

Urea nitrate has not found practical application, since it is not stable enough, although according to Kast [46] the loss of weight after 14 days at 75°C was only 0.2%. Decomposition into carbon dioxide, nitrous oxide, ammonium nitrate and urea takes place even at 140°C, and at 180°C decomposition is rather violent. Nevertheless a small sample of the substance does not explode. 

Urea nitrate is insensitive to friction and to impact. The density of the substance subjected to a pressure of 1500 kg/cm3 is 1.59 g/cm3. In the lead block test it caused an expansion of 260 (Kast) or 270 cm3 (T. Urbanski, Kapuscinski, Wojcie-chowski [59]). It detonates somewhat better than ammonium nitrate and guanidine nitrate, but a No. 8 detonator did not provoke complete detonation. Medard [59a] reported that urea nitrate gives a relative figure of the lead block expansion 79.6 (picric acid = 100) and the rate of detonation of 30 mm dia. charges is  

The second fertilizer that is often used as the basis for an explosive is urea. Pure urea is neither an explosive nor oxidizer. In fact, it is primarily a fuel. It can be mixed with AN to form an explosive mixture. In portions of the United States urea is routinely sold to de-ice sidewalks during the winter months. It comes in prill form, just like AN. 

When urea is mixed with nitric acid it chemically reacts, and one molecule of urea attaches to one molecule of nitric acid. This forms the explosive urea nitrate (UNi), with the chemical formula NH2CONH2-HNO3. In this explosive, the urea serves as the fuel and the nitric acid the oxidizer. 

The literature lists UNi as being 90% as powerful as TNT [5], Small-scale air-blast work displayed a far-field equivalency closer to 65% [12], Literature detonation velocities listed range from 3.4 to 4.7 km/s ( 11,200 to 15,400 ft/s) [13], The author has seen several different velocities in this region depending on the charge size and confinement. UNi possesses a low loading density (typically around 0.7 g/cm3). It is highly corrosive and readily attacks most metals. In terms of sensitivity, UNi is typically a tertiary explosives such as ANFO and requires a booster to be initiated. 

Urea nitrate secured its place on the U.S. landscape by being the explosive used in the World Trade Center (WTC) bombing in February of 1993. Although it was not commonly seen in the United States at the time, terrorist groups in other parts of the world had long since known about it. Both the Shining Path in Peru and numerous mideastern terrorists utilized UNi in their attacks well before the WTC incident. The use by the Shining Path was so predominant that sales of urea were outlawed in Peru in 1992 to curtail explosive production. 

The Palestinians have utilized UNi as a main charge explosive for many years. Along with TATP (to be discussed in the next section), it remains one of the main explosives in the Palestinian arsenal. A photograph taken by the author in the Gaza Strip shows a sample of Palestinian UNi (see Fig. 3.3). Urea in fertilizer form is seldom pure. It carries a good number of impurities that create a beige color in the final UNi. 

A simple, fast and specific color test for urea nitrate was reported recently by Almog et al. It is based on the reaction between urea nitrate and ethanolic solution ofp-dimethylaminocinnamaldehyde (p-DMAC) (9) under neutral conditions [91]. A red pigment is formed within 1 min from contact. Its structure has also been determined by the same group, by X-ray crystallography [92]. It appears to be a resonance hybrid between a protonated Schiffbase (10) and a quinoid system (10a) (Eq. (14)). The limit of detection on filter paper is 0.1 mg/cm. Urea itself, which is the starting material for urea nitrate, does not react with p-DMAC under the same conditions. Other potential sources of false-positive response such as common fertilizers, medications containing the urea moiety and various amines, do not produce the red pigment with p-DMAC. 

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Urea nitrate and oxalate. Prepare a concentrated aqueous solution of urea, (a) To one portion, add a few drops of cone. HNO the white... 

In experiments on the nitration of benzene in acetic acid, to which urea was added to remove nitrous acid (which anticatalyses nitration 4.3.1), the rate was found to be further depressed. The effect was ascribed to nitrate ions arising from the formation of urea nitrate. In the same way, urea depressed the rate of the zeroth-order nitration of mesitylene in sulpholan. ... 

The mixture was prepared and allowed to achieve equilibrium to it was added an excess of urea which caused the immediate precipitation as urea nitrate of the free nitric acid present. As a result of the sudden removal of the nitric acid from the mixture, the system underwent change to re-establish the equilibrium however, the use of an excess of urea removed the nitric acid as it was produced from acetyl nitrate and acetic acid, and the consumption of acetyl nitrate proceeded to completion. Thus, by following the production of urea nitrate with the time from the addition of urea, the rate of the back reaction could be determined, and by extrapolating the results to zero time the equilibrium... 

Nitration of aromatic amines with urea nitrate in sulfuric acid is reported to yield the -nitro derivative exclusively (44). When the para position is blocked, the meta product is obtained in excellent yield. 

Urea nitrate [124-47-0] M 123.1, m 152 (dec). Crystd from dilute HNO3. 

UREA HYDROGEN PEROXIDE UREA NITRATE UREA PEROXIDE... 

Kutty and Murthy [1159] have made a kinetic study of the solid—solid reaction between tricalcium phosphate and urea nitrate, a process of possible technological importance. A reduction in particle size, notably of Ca3(P04)2, increased the rate of reaction in powder mixtures and also changed the kinetic characteristics (318—338 K). Reaction in relatively coarse material (between —180 and +200 mesh) obeyed the parabolic... 

Methyl Nitrate,—Methyl nitrate was prepared from methyl alcohol, nitric acid, and urea nitrate by Mr. Willard McRary under the direction of Professor H. J. Lucas. The product was washed repeatedly with water and dried, and then was redistilled three times. 

BP, blood pressure BUN, blood urea nitrate CBC, complete blood cell count ECC, electrocardiogram HF, heart failure HR, heart rate K+, potassium SCr, serum creatinine SOB, shortness of breath. 

The nitrate decomposes explosively when heated [1], Prepared in the presence of phosphates, the salt is much more stable, even when dry [2], The manufacture and explosive properties of urea nitrate and its mixtures with other explosives are discussed in detail [3], Explosive properties of the nitrate are detailed [4],... 

To prepare the nitrate a few grammes of urea are dissolved in a few c.c. of water and concentrated nitric acid is added drop by drop. The salt separates in fine crystals. Urea nitrate is rather soluble in water, and this fact must be kept in mind when washing it. 

Urine (2 1.) in a porcelain basin is evaporated to a syrup on the water bath. The flame is extinguished and the hot syrup is stirred with 500 c.c. of alcohol. After some time the clear extract is decanted and the residue is again warmed and once more digested in the same way with 500 c.c. of alcohol. If necessary, the combined extracts are filtered, most of the alcohol they contain is removed by distillation, and the aqueous-alcoholic residue, after transference to a small porcelain basin, is evaporated to dryness on the water bath. The dry residue is well cooled and is kept in an efficient freezing mixture while two volumes of colourless concentrated nitric acid are slowly added with thorough stirring. After the product has stood for twelve hours, the paste of urea nitrate is filtered dry at the pump, washed with a little ice-cold nitric acid (1 1), again filtered with suction till no more liquid drains off, and suspended in 100-150 c.c. of warm water. To this suspension barium carbonate is added... 

TNT, trinitrotoluene UN, urea nitrate TAdD, theoretical maximum density. 

Urea nitrate (UN), more properly called uronium nitrate, is an energetic salt, and as such would not be expected to have much vapour pressure however, it might be detectable due to evolved urea or nitrogen oxides. Detection of urea nitrate is essential because for over a decade it has been a frequent choice of terrorists. It was used in the bombing of the World Trade Center in New York City (Februaryl 993) and in many car bombings in Palestine. In 1992, the use of urea nitrate became so prevalent in bombings by the Shining Path that sales of urea were outlawed in Peru. 

AN, ammonium nitrate DMNB, 2,3-dimethyl-2,3-dinitrobutane 2,4-DNT EGDN, ethylene glycol dinitrate HMX, C4H8N8O8 NG, nitroglycerin NM PETN, pentaerythritol tetranitrate RDX, C3H6N6O6 TATP, triacetone triperoxide TNT, trinitrotoluene UN, urea nitrate TMD, theoretical maximum density. 

J.C. Oxley, J.L. Smith and S. Naik, Determination of Urea Nitrate and Guanidine Nitrate Vapour Pressures by Isothermal Thermogravimetry , submitted to Propellants, Explosives, Pyrotechnics. 

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