Ammonium perchlorate, reaction with

EXPLOSION and FIRE CONCERNS combustible solid flammable moderate fire risk NFPArating (not rated) volatile in steam contact with strong oxidizing agents may cause fires and explosions violent reaction with ammonium perchlorate incompatible with tetrani-tromethane and mercury (II) nitrate thermal decomposition may generate carbon monoxide and carbon dioxide use alcohol foam, water spray, dry chemical powder, or carbon dioxide for fire fighting purposes. 

Oxidizers. The characteristics of the oxidizer affect the baUistic and mechanical properties of a composite propellant as well as the processibihty. Oxidizers are selected to provide the best combination of available oxygen, high density, low heat of formation, and maximum gas volume in reaction with binders. Increases in oxidizer content increase the density, the adiabatic flame temperature, and the specific impulse of a propellant up to a maximum. The most commonly used inorganic oxidizer in both composite and nitroceUulose-based rocket propellant is ammonium perchlorate. The primary combustion products of an ammonium perchlorate propellant and a polymeric binder containing C, H, and O are CO2, H2, O2, and HCl. Ammonium nitrate has been used in slow burning propellants, and where a smokeless exhaust is requited. Nitramines such as RDX and HMX have also been used where maximum energy is essential. 

Perchloric acid can be prepared by the treatment of perchlorates with sulfuric acid followed by distillation. A modification of the procedure (21) involves the reaction of ammonium perchlorate with nitric and hydrochloric acids, and then concentration at 198—200°C to eliminate the unreacted acids by vacuum distillation ... 

A considerable amount of research has been conducted on the decomposition and deflagration of ammonium perchlorate with and without additives. The normal thermal decomposition of pure ammonium perchlorate involves, simultaneously, an endothermic dissociative sublimation of the mosaic crystals to gaseous perchloric acid and ammonia and an exothermic solid-phase decomposition of the intermosaic material. Although not much is presently known about the nature of the solid-phase reactions, investigations at subatmospheric and atmospheric pressures have provided some information on possible mechanisms. When ammonium perchlorate is heated, there are three competing reactions which can be defined (1) the low-temperature reaction, (2) the high-temperature reaction, and (3) sublimation (B9). 

Some limitations of optical microscopy were apparent in applying [247—249] the technique to supplement kinetic investigations of the low temperature decomposition of ammonium perchlorate (AP), a particularly extensively studied solid phase rate process [59]. The porous residue is opaque. Scanning electron microscopy showed that decomposition was initiated at active sites scattered across surfaces and reaction resulted in the formation of square holes on m-faces and rhombic holes on c-faces. These sites of nucleation were identified [211] as points of intersection of line dislocations with an external boundary face and the kinetic implications of the observed mode of nucleation and growth have been discussed [211]. 

Nickei powder gives rise to dangerous reactions, which has led to accidents with potassium perchlorate (ignition), with chlorine at 600°C (ignition) and with ammonium nitrate at about 200°C (detonation). It catalyses the explosive decomposition of hydrogen peroxide. 

A bromide was introduced in the reaction instead of a fluoride in performing the anodic oxidation of a-stannyl ethers in dibromomethane solvent with tetrabutyl-ammonium perchlorate as the electrolyte (Scheme 19) [28]. The bromide ion was generated by the reduction of the solvent at the cathode of an undivided cell. 

Aluminum (Al) is a silver-colored light and soft metal used as a major component of aluminum alloys, which are used to construct aircraft and vehicles, similar to Mg alloys. However, Al is known as a readily combustible metal. Thus, Al particles are used as major fuel components of pyrolants. Al particles are mixed with ammonium perchlorate particles and polymeric materials to form solid propellants and underwater explosives. The reaction between aluminum powder and iron oxide is known as a high-temperature gasless reaction and is represented by ... 

In any event, it is clear from Table 3.3 that potassium nitrate is inferior to potassium perchlorate and the ammonium salts in terms of the volume of gas liberated at STP, the heat of reaction with carbon and the minimalisation of smoke (i.e. solid products). 

Mixtures of ammonium perchlorate with fuels can produce high temperatures when ignited, and the hydrogen chloride (HCl) liberated during the reaction can aid in the production of colors. These two factors make ammonium perchlorate a good oxidizer for colored flame compositions (see Chapter 7). 

A solid oxidizer Ammonium perchlorate (NH C10 ) is the current favorite due to the high percentage of gaseous products it forms upon reaction with a fuel. 

Strong oxidants such as ammonium perchlorate or other highly reactive species such as hydrides should be limited or excluded from the ChemChar process to prevent a runaway reaction or explosion. Wastes can be pretreated to remove such compounds prior to treatment with ChemChar. 

OB —6.1% hygroscopic crysts. It can be prepd by reaction of die diamine with Ammonium Perchlorate. Power by Ballistic Mortar 135% TNT Power by Trauzl Test 144% Sensitivity to Impact FI >PETN Refs 1) Beil 4, (399) (4841 2) A.H. 

In the manufacture of PVC plastisol propellants, the usual care is taken to assure that all ingredients meet specifications for chemical composition, dryness, and particle size. Since PVC plastisol propellants do not involve chemical reaction in their curing process, however, the presence of certain impurities in the ingredients is far less critical than with those propellant systems that are solidified by polymerization reaction. Ammonium perchlorate, the most common oxidizer, can normally be procured from the supplier with the required low moisture content. If not, it is dried immediately before use. Tray dryers or other drying means may be used, depending upon the quantity of material. Normally, some or all of the oxidizer must be ground to achieve the desired mean particle size and particle-size distribuion. High speed hammer mills have proved... 

Ammonia is generated by the reaction of diphenylguanidine and magnesium oxide with ammonium perchlorate. The cure rate of polysulfide propellant formulations can be a function, of the amount of ammonia removed during the mix cycle. Frequently, a vacuum is placed on uncured propellant to remove entrapped air. Too long a vacuum mix cycle, with polysulfide propellants, can remove excess ammonia changing the reaction condition during cure. 

The reaction of epoxides with carboxylic acids in the presence of ammonium perchlorate can be very slow. The search for a catalyst to accelerate the cure rate for a particular formulation can be particularly rewarding. The slowness of the reaction can lead to a disadvantage of the system if not carefully investigated. If cure is stopped before all of the epoxide groups have been consumed, cure will continue at a rate which depends on storage temperature. The epoxide can continue to react with carboxyl groups rapidly at elevated temperatures, or very, very slowly at ambient temperature, to yield highly crosslinked propellant systems with low strain capability. 

Curing Agents for Carboxyl-Terminated Polybutadiene Prepolymers. The types of curing agents used to prepare binders for CTPB propellants are the same as those for PBAN or PBAA. The bifunctionality of CTPB, however, requires that part of the curing agents be polyfunctional to provide for the formation of the tridimensional network. Almost without exception, the polyfunctional aziridines and epoxides used with CTPB undergo side reactions in the presence of ammonium perchlorate, which affects the binder network formation. Kinetic studies conducted with model compounds have established the nature and extent of the cure interference by these side reactions. The types and properties of some of the crosslinkers and chain extenders used to prepare solid propellants are summarized in Table IV. 

Epoxides. Epoxy compounds react with the carboxyl groups of CTPB to form polyesters. The reaction rates and extent of reaction of a number of epoxides have been determined with the model compound hexanoic acid (6). It was found that most epoxides undergo side reactions (as evidenced by the more rapid consumption of epoxide species) but that at least one difunctional epoxide, DER-332 (Dow Chemical Co.) (Table IV), exhibits a clean reaction with carboxylic acids, even in the presence of ammonium perchlorate. 

The results of model compound studies with three different types of epoxides, obtained in the presence and absence of ammonium perchlorate are shown in Figures 4, 5, and 6. The epoxide DER-332 shows a uniform rate of disappearance for the acid and epoxide species in this reaction. In the presence of ammonium perchlorate, the rate is increased, and a minimum of side reactions occur. Similar data but faster reaction rates are obtained with Epon X-801, but the consumption of epoxide species by side reactions is increased, particularly in the presence of ammonium perchlorate. On the other hand, the epoxide ERLA-0510 (Table IV), which contains a basic nitrogen, shows a reaction rate which is an order of magnitude greater than that for DER-332, accompanied by a substantial increase in side reactions. In the presence of ammonium perchlorate, the side reactions of ERLA-0510 predominate. In all probability, the side reactions of the multifunctional epoxides studied are homopolymerization. 

Figure 5. Rate of reaction of hexanoic acid with Epon X-801. Curves 1 and 2, no ammonium perchlorate Curves 3 and 4, 83 wt. % ammonium per-chlorate (average diameter — 130jjl)...

Propellant Aging. Three structurally different chemicals and mixtures of these materials have been used to cure CTPB propellants. These are MAPO, other aziridines which do not contain the P—N bond, and epoxides. As stated in the discussion of curing agents, the aging behavior of CTPB propellants prepared with these materials is distinctly different, owing to the behavior of these compounds and their reaction products in the presence of ammonium perchlorate and at elevated temperatures. 

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