Ammonium nitrate, bonding

Polymer-based rocket propellants are generally referred to as composite propellants, and often identified by the elastomer used, eg, urethane propellants or carboxy- (CTPB) or hydroxy- (HTPB) terrninated polybutadiene propellants. The cross-linked polymers act as a viscoelastic matrix to provide mechanical strength, and as a fuel to react with the oxidizers present. Ammonium perchlorate and ammonium nitrate are the most common oxidizers used nitramines such as HMX or RDX may be added to react with the fuels and increase the impulse produced. Many other substances may be added including metallic fuels, plasticizers, stabilizers, catalysts, ballistic modifiers, and bonding agents. Typical components are Hsted in Table 1. 

In commercial practice, powdered explosives on an ammonium nitrate basis are used in most cases. Typical detonation velocities are between 1800 and 3500 m/s depending on the metal system to be bonded. The lower detonation velocity range is preferred for many metal systems in order to minimize the quantity of solidified melt associated with the bond-zone waves (12). In addition, subsonic detonation velocity explosives are required for the parallel cladding technique in order to avoid attached shock waves in the coUision region, which preclude formation of a good bond. 

Of the eight nonmetals listed in Table 21.1, nitrogen is by far the least reactive. Its inertness is due to the strength of the triple bond holding the N2 molecule together (B.E. N=N = 941 kj/mol). This same factor explains why virtually all chemical explosives are compounds of nitrogen (e.g., nitroglycerin, trinitrotoluene, ammonium nitrate,... 

Formation of complex 26 by oxidation of the allenylidene-acetylide derivative 25 with cerium(IV) ammonium nitrate merits to be highlighted since 26 represents a unique example in which two allenylidene ligands are bonded to a metal (Scheme 10) [181]. 

The head-to-head trans-cyclorimer 92 of 9-vinylcarbazole (see Section II,C,2) undergoes C—C bond fission by a one-electron oxidative process on treatment with cerium ammonium nitrate or tris-(p-bromophenyl)ammo-niumyl hexachloroantimonate in methanol giving 93. ... 

R. Abegg, A. Kanitz, and 0. Pulvermacher have measured the viscosity of soln. of ammonium nitrate, and H. Gorke the reciprocal of the viscosity, i.e. the fluidity at different temp, (water at 25° unity), and his measurements are indicated in Table LXI. A. Kanitz also measured the viscosities of mixtures of ammonium nitrate with potassium, sodinm, or barium nitrate, and found that the results follow the additive rule very closely. W. N. Bond studied the plasticity of crystals of ammonium nitrate. 

In method 5 ammonium nitrate not only supplies the necessary number of nitr-amino groups, but also brings about the loss of molecules of formaldehyde from the intermediate products of types (XXV) and (XXVII). If the time is too short for the esterification of the alcohol (XXIII), nitrolysis of this compound occurs first at the bond P (not at bonds L, Mand I as in the acetylated product (XX)) and cyclonite is formed. 

Boronic acids can be reversibly esterified with resin-bound diols (Figure 3.15). The resulting boronic esters are stable under the standard conditions of amide bond formation, but can be cleaved by treatment with water under acidic or neutral conditions to yield boronic acids. Treatment of the resin-bound boronic esters with alcohols yields the corresponding boronic esters [197]. Resin-bound boronic esters are suitable intermediates for the Suzuki reaction [198], Treatment with H202 leads to the formation of alcohols (Entry 8, Table 3.36), while treatment of resin-bound aryl boronates with silver ammonium nitrate leads to the conversion of the C-B bond into a C-H bond (Entry 14, Table 3.46). 

Arylboronic acids esterified with support-bound 1,2-diols undergo Suzuki reaction with aryl iodides, whereby biaryls are released into solution (Entry 13, Table 3.46). This technique has also been used to prepare (3-turn mimetics by simultaneous macro-cyclization and cleavage from the support [766]. Alternatively, the C-B bond of a resin-bound boronate may be converted to a C-H bond by treatment with aqueous silver ammonium nitrate (Entry 14, Table 3.46). 

Kamogawa, and Sekiya (54) studied the graft polymerization of acrylamide onto cotton fabric using ceric ammonium nitrate as the catalyst. Similarly to Kulkarni et al. (35) the authors performed subsequent cross-linking with formaldehyde amd methylol compounds. From precipitation studies by acidification of cuprammonium solutions on mixtures of polyacrylamide and cellulose on the one hand and polyacrylamide-cellulose grafts on the other the authors conclude that chemical bonds must exist between the two polymers in the grafted product. 

Christie and Breckenridge (42) describe the application of this column to the isolation and determination of FAs containing trans double bonds in samples of natural and industrial origin. A column (250 X 4.6-mm ID) of NUCLEOSIL 5SA was flushed with 1% ammonium nitrate solution at a flow rate of 0.5 ml/min for 1 h, then with distilled water at 1 ml/min for 1 h. Silver nitrate (0.2 g) in water (1 ml) was injected onto column via the Rheodyne valve in 50-yu.l aliquots at 1-min intervals silver began to elute from the column after about 10 min, and 20 min after the last injection the column was washed with methanol for 1 h, then with 1,2-dichloroethane-dichloromethane (1 1 v/v) for 1 h. For most of the analytical work, the column temperature was maintained at 30°C in a thermostatted oven. 1,2-Dichloroethane-dichloromethane (1 1) (mixture A) at a flow rate of 1.5 ml/min was the mobile phase (detector operated at 242 nm) for the separation of isomeric monoenes, and the same solvents with the addition of 0.5% acetonitrile (mixture B) at a flow rate of 0.75 ml/min were employed for isomeric dienes and trienes. 

The C-Si bond of an SMA can also be cleaved by oxidizing reagents like cerium ammonium nitrate (CAN). Starting from (V-bis(trimethylsilyl)methylazetidinones, treatment with CAN probably leads to the oxidation product of the two C-Si bonds, i.e., the corresponding disilylketal that is hydrolyzed into the formamide to give the N-H azetidinones (yields >80%). This constitutes an alternate and more efficient way to sequential fluoride-induced desilylation. Peterson olefination, ozonolysis, and formamide decomposition when deprotection of bis(trimethylsilyl)methylated azetidinones into NH-azetidinones is required.228,230... 

This intermolecular potential for ADN ionic crystal has further been developed to describe the lowest phase of ammonium nitrate (phase V) [150]. The intermolecular potential contains similar potential terms as for the ADN crystal. This potential was extended to include intramolecular potential terms for bond stretches, bond bending and torsional motions. The corresponding set of force constants used in the intramolecular part of the potential was parameterized based on the ab initio calculated vibrational frequencies of the isolated ammonium and nitrate ions. The temperature dependence of the structural parameters indicate that experimental unit cell dimensions can be well reproduced, with little translational and rotational disorder of the ions in the crystal over the temperature range 4.2-250 K. Moreover, the anisotropic expansion of the lattice dimensions, predominantly along a and b axes were also found in agreement with experimental data. These were interpreted as being due to the out-of-plane motions of the nitrate ions which are positions perpendicular on both these axes. 

D In a double replacement reaction the positive and negative ions switch partners. Ammonium will bond with the nitrate ion and the barium ion will bond with phosphate. 

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