Urea nitrate nitration with

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... 

The colorimetric reaction of urea nitrate with p-DMAC [91] was also adopted as a field test, UN-1. The reagent (0.4% in ethanolic solution) is sprayed on the sample, or on the suspected area, and the appearance of a red color within 1 min indicates the presence of urea nitrate [103]. 

NNH2,CH3N303 mw 105.06 N 39.98% OB to C02 —7.61% colorl platelets (from ethanol plus eth) mp 158.4—.8° (decompn). Freely sol in acet, acetic acid and ethanol sol in hot w (forms cyanic acid and nitroamide) si sol in benz, chlf and petr eth. CA Registry No [556-89-8]. Prepn is by dehydration of Urea Nitrate with coned sulfuric acid. The compd can be detonated but is not sensitive to percussion or heating (Ref 7)... 

It is synthesized by dehydration of urea nitrate with sulfuric acid. 

Urethan. Carbamic acid ethyl ester ethyl carbamate urethane ethyl urethan. C3H,NO, mol wt 89.09. C 40.44%-, H 7.92%, N 15.72%, O 35.92%,. NH2COOC2H5. Prepd by heating urea with alcohol under pressure by warming urea nitrate with alcohol and sodium nitrite. Toxicity data K. J. Franklin, J, Pharmacol. Exp. Ther. 42, 1 (1931). Review of carcinogenic action and metabolism Mirvish in Advan. Cancer Res 11, 1-42 (1968). 

Evidence from the viscosities, densities, refractive indices and measurements of the vapour pressure of these mixtures also supports the above conclusions. Acetyl nitrate has been prepared from a mixture of acetic anhydride and dinitrogen pentoxide, and characterised, showing that the equilibria discussed do lead to the formation of that compound. The initial reaction between nitric acid and acetic anhydride is rapid at room temperature nitric acid (0-05 mol 1 ) is reported to be converted into acetyl nitrate with a half-life of about i minute. This observation is consistent with the results of some preparative experiments, in which it was found that nitric acid could be precipitated quantitatively with urea from solutions of it in acetic anhydride at —10 °C, whereas similar solutions prepared at room temperature and cooled rapidly to — 10 °C yielded only a part of their nitric acid ( 5.3.2). The following equilibrium has been investigated in detail ... 

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 maybe reacted with acetoacetic ester and that product nitrated to give 5-nitro-orotec acid That is hydrogenated, then reacted with urea and potassium cyanate to give tetrahydroxypy-imidopyrimidine. The tetrahydroxy compound Is converted to the tetrachloro compound POCI3. Reaction with diethanolamine and then with piperidine gives dipyridamole. 

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. 

OS 50] [R 17] [R 26] [P 36] By nitration of N,N -diefhyl-N-nitroso-urea the target compound for DNDA synthesis N,N -diethyl-N-dinitro-urea was achieved with 100% selectivity [38],... 

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],... 

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... 

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. 

DMAC does not detect urea, but uronium ion (8). Another color test for urea nitrate, which is less specific but is simple and quick, was developed in Israel by A. Bomstein. It is based on the fact that urea nitrate is highly acidic thus, the pH indicator bromophenol blue changes its color from blue to yellow upon reaction with trace amounts of urea nitrate [95]. Red pigment formation in the reaction between p-DMAC and urea nitrate [91, 92] is as follows ... 

Davis studied the dehydration of urea nitrates as a route to iV-nitroureas. The nitrate salt of iV-methylurea undergoes dehydration-rearrangement on treatment with concentrated sulfuric acid to give Af-nitro-A -methylurea in 42 % yield. In this compound the nitro and methyl groups are attached to the same nitrogen and so its hydrolysis can provide a route to methylnitramine. In contrast, the nitrate salts of ethyl, n-propyl, n-butyl and n-amyl ureas, give iV-nitro-A -ethylurea (49 %), A -nitro-A -propylurea (60 %), iV-nitro-iV -butylurea (67 %) and iV-nitro-A -amylurea (67 %), respectively, on treatment with concentrated sulfuric acid. 

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. 

While the preparation of phenylurea itself by the foregoing process does not appear in the older literature, an analogous process has been patented for the preparation of -phenetyl-urea,fi in which />-phenetidine is heated with urea nitrate (or -phenetidine hydrochloride with urea) in aqueous solution. This reaction appears to be generally applicable to aromatic primary amines it does not, however, appear to be so well suited to the preparation of the corresponding derivatives of secondary amines. 

Urea nitrate, dry or wetted with less than 20 per cent water, by mass 0220... 

Franchimont and Klobbie [17] prepared ethylenedinitramine (EDNA, Haleite) by the nitration of ethylene urea (2-imidazolidone) with a mixture of nitric and sulphuric acids. (According to Schweitzer [18], ethylene urea is obtainable either by the action of urea on ethylenediamine at 110°C (initially) to 240-250°C (finally) in quantitative yield or by the action of urea on ethylene glycol at 160-240°C in 55% yield. W. E. Bachmann et al. [19] prepared ethylene urea by the action of ethyl carbonate on ethylenediamine in approximately 60% yield.) Hydrolysis of the dinitroethy-lene urea so formed gives ethylenedinitramine. Bachmann recommends nitration with mixed nitric acid and acetic anhydride ... 

Nitrourea, like nitroguanidine, is prepared by the action of sulphuric acid on urea nitrate. It was recommended as an explosive by Badische Anilin und Soda-Fabrik in 1915 [62] but without success, as it was not sufficiently stable. In the presence of water it decomposes at a little above 60°C with the evolution of nitrous oxide. 

In all explosives of this kind the fusible constituent of the mixture was ammonium nitrate with other nitrates, e.g. of sodium, potassium or calcium (with water of crystallization), of organic bases such as methylamine, ethylenediamine, guanidine etc. and urea. Since on Solidification these mixtures become very dense and detonate with great difficulty, PETN, cyclonite or TNT were usually added. The composition of some of these mixtures is given in Table 47. 

---