Thermal decomposition of alkali metal perchlorates

The effect of past mechanical history on the subsequent thermal decomposition kinetics of sodium, potassium, rubidium and caesium perchlorates, has been investigated. At low temperatures the decomposition of all these salts is significantly sensitized by pre-compression. At high temperatures, however, prior compression results in a lowered decomposition rate in the case of potassium, rubidium and caesium perchlorates and in an increase in the thermal reactivity of sodium perchlorate. The high temperature behaviour is shown to be an indirect consequence of the low temperature behaviour. The difference in behaviour between sodium perchlorate and the other alkali metal perchlorates is explained on the basis of the stability of the respective chlorates, formed during the low temperature decomposition. This is substantiated by experiments which show that the addition of sodium chlorate to sodium perchlorate brings about a sensitization while potassium perchlorate admixed with potassium chlorate results in a desensitization at high temperatures.     

Synthesis of pyrylium salts and heterocyclic nitrogen bases from cycloalkenylacetic acid esters

2-Alkyl-6-methoxy-3,4-tetramethylene- and 3,4-pentamethylenepyrylium perchlorates were obtained by acylation of cycloalkenylacetic acid esters with aliphatic acid anhydrides. 2-Methyl-6-methoxy[2,3-c]cholestanopyrylium perchlorate was similarly synthesized. 2-Alkyl-3,4-tetramethylene-6-pyridones were isolated by treatment of 2-alkyl-6-methoxy-3,4-tetramethylene-pyrylium perchlorates with excess concentrated ammonium hydroxide. 2-Methyl-3,4-pentamethylene-6-aminopyridine was obtained by the action of excess concentrated ammonium hydroxide on 2-methyl-6-methoxy-3,4-pentamethylenepyrylium perchlorate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1323–1326, October, 1976.     

Determination of germanium by AAS in chloride-containing matrices

Interference effects of NaCl on the ET-AAS determination of Ge have been studied. The use of several matrix modifiers to alleviate this problem such as Ni and Zn perchlorates and nitrates, nitric acid, ammonium nitrate are reported. The stabilizing effect of Zn and Ni perchlorates allows the use of high pretreatment temperatures. NaCl is thus thermally volatilized from the atomizer by employing pretreatment temperatures higher than 1500 degrees C resulting in an improved sensitivity. Germanium levels in zinc plant slag samples, have been determined and compared to those obtained for the same samples spiked with NaCl with platform and wall atomization using nickel perchlorate as a matrix modifier. The results were compared with those from a hydride generation system equipped with a liquid nitrogen trap. The recoveries for germanium have been almost complete and amount to 99% for the original slag samples and 80% for 15% (w/w) NaCl containing spiked samples.     

Determination of germanium by AAS in chloride-containing matrices

Interference effects of NaCl on the ET-AAS determination of Ge have been studied. The use of several matrix modifiers to alleviate this problem such as Ni and Zn perchlorates and nitrates, nitric acid, ammonium nitrate are reported. The stabilizing effect of Zn and Ni perchlorates allows the use of high pretreatment temperatures. NaCl is thus thermally volatilized from the atomizer by employing pretreatment temperatures higher than 1500°C resulting in an improved sensitivity. Germanium levels in zinc plant slag samples, have been determined and compared to those obtained for the same samples spiked with NaCl with platform and wall atomization using nickel perchlorate as a matrix modifier. The results were compared with those from a hydride generation system equipped with a liquid nitrogen trap. The recoveries for germanium have been almost complete and amount to 99% for the original slag samples and 80% for 15% (w/w) NaCl containing spiked samples.     

Conductometric determination of quaternary ammonium salts by sodium perchlorate and vice versa

A conductometric method is proposed for the determination of quaternary ammonium salts (chloride or bromide), based on the poor solubility of the relative perchlorates. A comparison between expected and found values shows that the method is suitable, rapid, and easy for quantities in the range from 0.2 to 5 g. The error depends on the solubility of the relative perchlorate. The apparent and tentative solubility product of the studied compounds were calculated. The obtained values allowed to propose benzyltributyl ammonium chloride (BTBA Cl) as precipitant for the conductometric titration of perchlorate. This easy, rapid and accurate determination can be used to analyze the perchlorate ion even in concentrated solutions and to determine stability constants for complex formation in aqueous solutions.     

Oxidative nucleophilic substitution reaction of alkyl iodides upon treatment with perchlorate and dinitramide anions. Synthesis of alkyl-substituted perchlorates

Reactions of oxidative nucleophilic substitution of alkyl iodides with lithium perchlorate and dinitramide were studied. The reactions of alkyl iodides and lithium perchlorate, proceeding in the presence of nitronium tetrafluoroborate as an oxidant, furnished a series of new alkyl perchlorates, including those containing an adamantyl fragment. Spectral properties of alkyl perchlorates were studied in detail for the first time. The reactions of oxidative nucleophilic substitution of iodoacetic ester and lithium dinitramide, proceeding upon treatment with nitronium tetrafluoroborate or ozone, resulted in the substitution of an iodine atom with the nitrate anion.     

Thermal behaviour of chromium (III) perchlorate hexahydrate

Thermal behaviour of intimate mixtures of chromium(III) oxide and lithium¹, potassium², rubidium³, cesium³ and thallium(I)⁴ perchlorates revealed that chromium(III) oxide not only catalyses the decomposition by lowering the decomposition temperatures of the pure metal perchlorates but also chemically interacts resulting in the formation of metal dichromate. The oxidation of chromium(III) into the hexavalent state is attributed to the abstraction of oxygen from the perchlorate moiety during the decomposition. In this context, it was thought interesting to study the thermal behaviour of chromium(III) perchlorate and to identify the decomposition products in order to find out whether chromium(III) is oxidized into chromium(VI) by the perchlorate group. Except for a report⁵ on the preparation of chromium(III) perchlorate with different molecules of water of hydration no work seems to have been carried out on the thermal decomposition of this compound. In the present study, the decomposition characteristics are followed by TG and DTA techniques and the decomposition products have been examined by chemical analysis, X-ray powder diffraction patterns and infrared spectral measurements.     

Conductometric determination of quaternary ammonium salts by sodium perchlorate and vice versa

A conductometric method is proposed for the determination of quaternary ammonium salts (chloride or bromide), based on the poor solubility of the relative perchlorates. A comparison between expected and found values shows that the method is suitable, rapid, and easy for quantities in the range from 0.2 to 5 g. The error depends on the solubility of the relative perchlorate. The apparent and tentative solubility product of the studied compounds were calculated. The obtained values allowed to propose benzyltributyl ammonium chloride (BTBA Cl) as precipitant for the conductometric titration of perchlorate. This easy, rapid and accurate determination can be used to analyze the perchlorate ion even in concentrated solutions and to determine stability constants for complex formation in aqueous solutions. Received: 11 June 1997 / Revised: 8 October 1997 / Accepted: 11 October 1997     

Thermal ignition behaviour of ammonium perchlorate in presence of fuel-rich compounds

The thermal ignition behaviour of ammonium perchlorate has been investigated in the presence of fuel-rich compounds such as tetramethylammonium perchlorate, trimethylammonium nitrate, carbon and cellulose. The ignition characteristics, as studied by differential thermal analysis, have been found to be strongly influenced by self-decomposition and other physicochemical properties of the additives. For a simple system, an analytical model proposed on the basis of the coupling of two exothermic decomposition reaction kinetics and a heat-balance equation, appears to explain to some extent the observed trend in peak ignition temperature when the composition is varied. The salient features of the analysis, as regards its application to fuel-oxidizer interactions in general, have been pointed out.     

Combustion and thermal decomposition characteristics of composite solid propellan

The role of thermal decomposition of the binder and the oxidiser in the thermal decomposition, ageing and combustion of composite solid-propellants has been investigated. The present study shows that the burning rate and ageing of polystyrene and ammonium perchlorate propellant are related to the thermal decomposition of the propellant itself and ammonium perchlorate.     

Thermal decomposition of ammonium perchlorate

This review represents an attempt to summarize literature data on thermal decomposition of ammonium perchlorate. The mechanism of thermal decomposition and various factors which influence on the thermal decomposition of ammonium perchlorate are discussed.     

Thermal behavior and dismantlability of adhesives containing various inorganic salts

As a fundamental study on the development of dismantlable adhesives containing chemically reactive materials, the thermal behavior and dismantlability of an epoxy adhesive containing one of the twenty-seven inorganic salts (chlorides, perchlorates, and nitrates) were observed. In the thermal behavior measured by the differential scanning calorimetry, epoxy adhesives with inorganic salts containing iron, copper, zinc, and aluminum cations released heats of reaction at lower temperatures than the adhesive alone or the adhesives with other inorganic salts. Since such inorganic salts were considered to be effective candidates as fillers in dismantlable adhesives, the adhesion strengths of their mixtures with the adhesive were observed after heat aging at 270 °C for 30 min. The results showed that both chloride and perchlorate salts specifically decreased the adhesion strength after heating. On the other hand, the effect of nitrate salts on the decrease in adhesion strength was low in comparison with the chloride and perchlorate salts.     

Thermal characterization of tetramethylphosphonium perchlorate, -nitrate and -picrate

Tetramethylphosphonium perchlorate, -nitrate and -picrate have been characterized thermally employing differential thermal analysis and thermogravimetric techniques. The thermal stability of these compounds is found to be in the order, perchlorate>nitrate>picrate. A similar trend is stability has been obserbed in the case of the corresponding ammonium compounds. These observations have been explained in terms of the dissociation of these salts prior to their decomposition. Explosion sensitiveness of these compounds has been determined by explosion delay measurements which also seem to indicate the same order of relative stability. The ammonium compounds appear to be more stable than their phosphonium counterparts.     

The effects of fast neutron,gamma-ray and combined radiations on the thermal decomposition of ammonium perchlorate powder-aluminum particle mixtures

The thermal decomposition kinetics of irradiated and unirradiated ammonium perchlorate and ammonium perchlorate powder-aluminum particle mixtures has been studied by determining decomposition gas pressurevs. heating time with samples at a controlled temperature Qualitatively the radiation induced changes are similar to those obtained in previous studies on ‘pure’ ammonium perchlorate. The induction period is shortened and the acceleratory and decay period rate constants are increased. The data have been analyzed using Avrami-Erofeev kinetics. The results for pure unirradiated material are in accord with published results. The activation energies for the induction, acceleratory and decay periods for pure pellets were found to be 133.5±6.7, 131.8±6.7 and 127.2±6.7 kJ·mol, respectively. Samples were exposed to either a single gamma-ray irradiation, fission neutron irradiation followed by a gamma-ray irradiation, or to a proton irradiation. When compared on an equal energy deposited basis, the fast neutron induced changes are appreciably larger than the gamma-ray changes. However, the proton induced changes are comparable or slightly more than the gamma-ray effects. Some, or all, of the fast neutron effects can be attributable to the concentrated radiation damage ‘spikes’ along the path of lattice atom recoils. It is likely that these become thermal decomposition sites when the crystals are heated. Protons create fewer spikes than fast neutrons. Overall, the results indicate that any ammonium perchlorate-aluminum propellant mixtures that may be exposed to radiation environments, such as used in this study, should be subjected to a thorough radiation effects analysis if reliable performance is required. In celebration of the 60^th birthday of Dr. Andrew K. Galwey     

Thermogravimetric analysis of cobalt sulfate

Morpholine is a base of moderate strength, comparable with that of ammonia, and capable of forming -onium-type salts. Extensive studies [1,2] have been made on the thermal stability of ammonium perchlorate because of its technological use as an oxidant in solid state rocket propellants. The preparation, characterization and thermal behaviour of morpholinium perchlorate are reported in this note. The study was followed by XRD, IR, TG, DTA and mass spectral techniques.     

Synthesis of N-methylpentafluorophenylpyridinium salts

Di- and triaryl-N-methylpyridinium perchlorates bearing pentafluorophenyl groups have been obtained by reaction of the appropriate pyrylium salts with methylamine. In the case of 4-phenyl-2,6-bis(pentafluorophenyl)pyrylium perchlorate, a stable 2H-pyran intermediate was isolated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1100–1103, August, 1991.     

Thermochemical investigations of natural phosphate with ammonium sulfate additive

Summary The free energy of the acidic ammonium sulfate is a good precondition its use as an additive or reagent for decomposition of natural phosphates on the way to obtain NPS or NPKS complex fertilizers. During our previous studies it was confirmed that as a result of thermo-mechanical treatment new solid phases are formed as a result of the phosphates decomposition. The aim of this study is to find out appropriate conditions for thermal treatment of Tunisia phosphorite with ammonium sulfate where the content of P₂O₅ soluble forms has its maximum. The process was investigated under dynamic thermal conditions. Structure and phase transformations of the mixtures to intermediate and final solid products are confirmed by different techniques. X-ray powder diffraction, infrared spectroscopy and electron microscopy have been applied successfully and relationship found between phase structure and thermal treatment applied. As a result of the complex studies optimal temperatures are determined. The solid products under optimal conditions contain phosphorous in soluble forms available for plants in the soil. As a final it is concluded that the final products could be used as complex mineral fertilizers.     

Synthesis of 6-hetaryl-substituted azulenes and their reactions with 2,6-diphenylpyrylium perchlorate

A method for the synthesis of 4,6,8-trimethyl- and 4,8-dimethyl-6-(2-thienyl, 2-benzothiazolyl) azulenes from 2,6-dimethyl-4-(methyl, 2-thienyl, 2-benzothiazolyl)-pyrylium perchlorates and cyclopentadienyllithium is described. The possibility of direct pyrylation of azulenes with 2,6-diphenylpyrylium perchlorate is demonstrated. Azulenes with a pyrylium ring in the 1 position were synthesized, and their behavior with respect to ammonium acetate was investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1045–1047, August, 1980.     

Effect of tetramethylammonium perchlorate on ammonium perchlorate and propellant decomposition

The thermal decomposition of ammonium perchlorate (AP) is considerably modified when it is cocrystallized or mixed with small amounts of tetramethyl- ammonium perchlorate. The decomposition is sensitized when tetramethylphosphonium perchlorate is added to AP. The effect on the isothermal decomposition of AP when it is mixed with tetramethylammonium perchlorate, appears to be similar to that of AP-based composite propellant having the same mixed AP composition.     

Polyfuryl(aryl)alkanes and their derivatives. 5. Cations and radicals in the polyfuryl(aryl)methane series

The perchlorates of trifuryl- and difuryl(aryl)carbene have been prepared by the oxidation of polyfuryl(aryl)-methanes with trityl perchlorate and have been characterized. The temperature dependence of the PMR and ¹³C NMR spectra of the cations suggests that they exist in solution in the form of various rotamers. X-ray diffraction has been used to establish that the tris(5-methyl-2-furyl)carbene perchlorate molecule is a symmetrical propeller in which each furan ring is twisted from the plane by 10.4°. Reduction of the corresponding perchlorates on a zinc mirror in tetrahydrofuran gives stable polyfuryl(aryl)-methane radicals which were recorded by ESR spectroscopy.For Communication 4, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 329–337, March, 1993.