Propylene Glycol Dinitrate Research Articles

Propylene Glycol Dinitrate (PGDN) as an Explosive Taggant

Propylene Glycol Dinitrate (PGDN) is a liquid nitrate ester explosive which has been used as a gelatinating agent in some energetic formulations. The aim of the present work was to assess whether PGDN could be used as a detection taggant. The PGDN was synthesized in the laboratory using laboratory grade propylene glycol (PG). The purity of the synthesized PGDN was assessed using gas chromatography-mass spectrometry (GC/MS) and Fourier transform infrared spectroscopy (FTIR). A study of the thermal decomposition of PGDN was carried out using both DSC and thermogravimetry-mass spectrometry analysis (TG/MS) methods. The gases produced during thermal decomposition were identified by mass spectrometry and the influence of the heating rate was investigated. The duality of DSC-TGA was highlighted by studying the complementarity between these two methods. Vapour pressure and enthalpy of vaporisation of PGDN were considered as the foremost taggant characteristics, and were estimated using TGA and taking benzoic acid as the reference. The vapour pressure of PGDN at ambient temperature is 2.54 Pa, therefore the PGDN could be a good candidate as a detection taggant compared to other explosive taggants (Nitroglycerin, EGDN, DMNB and PDCB).

Rapid and sensitive measurements of nitrate ester explosives using microchip electrophoresis with electrochemical detection

This article describes an effective microchip protocol based on electrophoretic-separation and electrochemical detection for highly sensitive and rapid measurements of nitrate ester explosives, including ethylene glycol dinitrate (EGDN), pentaerythritol tetranitrate (PETN), propylene glycol dinitrate (PGDN) and glyceryl trinitrate (nitroglycerin, NG). Factors influencing the separation and detection processes were examined and optimized. Under the optimal separation conditions obtained using a 15 mM borate buffer (pH 9.2) containing 20 mM SDS, and applying a separation voltage of 1500 V, the four nitrate ester explosives were separated within less than 3 min. The glassy-carbon amperometric detector (operated at -0.9 V vs. Ag/AgCl) offers convenient cathodic detection down to the picogram level, with detection limits of 0.5 ppm and 0.3 ppm for PGDN and for NG, respectively, along with good repeatability (RSD of 1.8-2.3%; n = 6) and linearity (over the 10-60 ppm range). Such effective microchip operation offers great promise for field screening of nitrate ester explosives and for supporting various counter-terrorism surveillance activities.

The Interaction between Otto Fuel II and Aqueous Hydroxylammonium Perchlorate (HAP), Part III: Depletion of Components within the Reacting Liquids

AbstractGas chromatography (GC) with a Flame Ionisation Detector (FID) has been used to determine changes in the concentrations of the components of Otto Fuel II (OF) in contact with an 82% aqueous solution of hydroxylammonium perchlorate (HAP) in sealed vials at 31.7 °C during the period leading up to auto‐ignition of the two liquids. The concentration of hydroxylamine in HAP was monitored over the same period using a titration method. It was found that 2‐nitrodiphenylamine (2NDPA), the stabiliser in the OF, is completely consumed after about 65–70 h and that the concentration of hydroxylamine begins to fall at this point. 1,2‐Propanediol dinitrate (propylene glycol dinitrate, PGDN), the energetic component in the OF, is not depleted significantly until after about 90 h. The evolution of nitrous oxide (N2O) between 65 and 90 h is attributed to the reaction of the hydroxylammonium ion with nitrous acids produced by PGDN decomposition at the liquid‐liquid interface. Carbon dioxide (CO2) is evolved after ~ 90 h and is attributed to PGDN decomposition. HAP and PGDN are each thought to contribute to N2O evolution after ~ 90 h.

The Interaction between Otto Fuel II and Aqueous Hydroxylammonium Perchlorate (HAP), Part II: Gas Evolution and Changes in HAP Solution Acidity

AbstractHeadspace gas analysis has shown that nitrous oxide (N2O) is the principal gas evolved during contact between small volumes of Otto Fuel II (OF) and 82% aqueous hydroxylammonium perchlorate (HAP) at temperatures close to ambient. The gas is produced mainly from the 82% HAP layer and is generated in significant amounts only after the OF has become blackened as a result of extreme degradation. The pH of the HAP solution falls during contact with OF and the OF blackening point is the same for each of three storage temperatures investigated, suggesting that the production of N2O may depend upon the attainment of a specific HAP solution acidity. It is suggested that the propyleneglycol dinitrate (PGDN) component in OF undergoes acid hydrolysis at the liquid/liquid interface and that the nitric acid produced leads to the decrease in HAP solution pH and to stabilizer depletion in OF. Experiments involving contact between 82% HAP and the other components of OF confirm the key role of PGDN: in its absence there is no change in HAP solution acidity, no gas evolution and no violent reaction between the two liquids.

Measurement and calculation of the ideal detonation velocity for liquid nitrocompounds

Results of experimental measurements are presented for the dependence of the detonation velocity on the charge diameter for homogeneous nitromethane and propylene glycol dinitrate and for the ideal detonation velocities for allyl nitrate, diethlyene glycol dinitrate, methylene glycol dinitrate, and ethyl nitrate. Literature data on measurement of the dependence of the detonation velocity on the charge diameter for liquid TNT, nitroglycerin, glycol dinitrate, and methyl nitrate are collected. It is shown that measured values of the ideal detonation velocity are in good agreement with calculated values obtained by the SD method, which uses the equation of state of materials at a high pressure (see B. N. Kondrikov and A. I. Sumin, Fiz. Goreniya Vzryva, No. 1, 1987). A correlation between the ratio of the critical detonation velocity to the ideal velocity and the heat of explosion is obtained, which makes it possible to estimate the limiting value of the latter at which homogeneous liquid nitrocompounds lose detonatability.

Biological denitration of propylene glycol dinitrate by Bacillus sp. ATCC 51912

Biological denitration of propylene glycol dinitrate by Bacillus sp. ATCC 51912

Wet air oxidation of energetics and chemical agent surrogates

Abstract Wet air oxidation studies have been conducted on a number of energetic materials and wastewaters derived from energetic materials to demonstrate high destruction levels of specific energetic components. Triple-base propellant, OTTO Fuel (used as a torpedo propellant) and hydrazine-based rocket fuel were energetics of interest. Triple-base propellant contain nitrocellulose, nitroglycerin, and nitroguanidine. OTTO Fuel contains substantial amounts of propylene glycol trinitrate. Hydrazine based rocket fuel contains hydrazine and 1,1-dimethylhydrazine (asymmetrical dimethyl hydrazine or UDMH). A bench scale wet air oxidation study on alkaline hydrolyzates of triple-base propellants indicated that essentially complete destruction of the reactive nitrogen components could be achieved at an oxidation temperature of 280°C. Bench scale wet air oxidation studies on OTTO Fuel wastewaters indicated that a 99+ percent destruction of propylene glycol dinitrate can be achieved at an oxidation temperature of 280°C. Processing OTTO Fuel wastewaters in a continuous flow, full scale wet air oxidation unit achieved even higher destruction levels. Bench scale wet air oxidation studies on hydrazine-based rocket fuel wastewaters indicated that a 99.8 percent destruction of hydrazine and a >99.0 percent destruction of 1,1-dimethylhydrazine can be achieved at an oxidation temperature of 280°C. Again, processing of hydrazine-based rocket fuel wastewaters in a continuous flow, full scale wet air oxidation unit achieved similar destruction levels. The application of wet air oxidation for the destruction of chemical agents has been made by the extrapolation of data from the wet air oxidation of compounds with similar chemical structures or of surrogate compounds. Sarin and V-agents are nerve agents which have an organo-phosphorus structure similar to that of certain commonly used pesticides. Pesticides such as glyphosate and malathion, which have a similar organo-phosphorus structure, are essentially completely destroyed (>99 percent destruction) by wet air oxidation in the temperature range of 200 to 280°C. The chemical agent surrogate, dimethyl methyl phosphonate (DMMP) was wet air oxidized at temperatures of 220 to 280°C. Alkaline hydrolyzed DMMP was wet air oxidized at 280°. All of the oxidized effluents showed a >97.5 percent destruction efficiency for the DMMP. The blister agent, mustard (HD) is a chlorinated sulfide, bis(2-chloroethyl) sulfide. Organic sulfides such as mercaptans can be destroyed by wet air oxidation at 260 to 280°C. It is concluded that the wet air oxidation process is a promising alternative to incineration for disposal of energetics and chemical warfare agents.

Effect ofpropylene glycol 1,2-dinitrate on cerebral blood flow in rats: a potential biomarker for vascular headache?

Two measurable indices of toxicity that can be correlated with exposure to propylene glycol dinitrate (PGDN) were evaluated along with its metabolism. Propylene glycol dinitrate was administered by rapid i.v. injection to male Fischer-344 rats. These rats demonstrated a dose-response of blood pressure (BP) to doses of PGDN ranging from 0.1 to 30 mg/kg; the maximum fall in systolic BP occurred within l min of dosing. The i.v. administration of PGDN to separate groups of animals resulted in an increase in cerebral blood flow that was correlated with the dose, but a clear dose-response was not obtained.

Effect of exposure route on measurement of blood pressure by tail cuff in F-344 rats exposed to OTTO Fuel II

Male Fischer-344 rats demonstrated a dose-response of blood pressure (BP) to increasing doses of propylene glycol dinitrate (PGDN), the major constituent of OTTO Fuel II (OFII) following administration by subcutaneous injection. Dermal application of the same doses to separate groups of rats resulted in variable responses of BP that were unrelated to dose. A nose-only exposure system was developed but no effect on BP was observed in rats exposed to a nearly saturated atmosphere of PGDN (approx. 750 mg m 3 at 25°C). This study has indicated both the difficulties associated with the use of tail cuff measurement of BP and the need for either a more sensitive or more specific biomarker of effect for exposure to nitrate esters.

Gas chromatographic determination of propylene glycol dinitrate in rodent skin.

A gas chromatographic (GC) method was developed for the detection of propylene glycol dinitrate (PGDN) in rodent skin following extraction with ethyl acetate. Known quantities of PGDN contained in the torpedo fuel Otto Fuel II were added to homogenates of rat skin, which were subsequently extracted with two 10-mL portions of ethyl acetate. An aliquot of each extract was analyzed by GC with a flame ionization detector. With this method, concentrations ranging from 0.0042 to 11.2 mg/mL were determined by comparison with a standard curve. The extraction efficiencies ranged from 85.7% for the lowest concentration to 101% for the highest concentration.

A review of propylene glycol dinitrate toxicology and epidemiology

Propylene glycol dinitrate (PGDN) is a rapidly metabolized, nitrated ester explosive propellant with acute cardiovascular effects at lower levels of exposure and methemoglobinemia and vascular collapse at higher ones. Exposure can be by dermal or inhalation routes. Toxicology has played an important role in setting workplace permissible exposure limits, which have been limited by vascular headaches and subtle, transient decrements in central nervous system performance. Less well characterized is the etiology of excess, long-term cardiac morbidity in PGDN-exposed workers. Human central nervous system degeneration and links to infectious diseases are unsubstantiated concerns.

Motor performance effects of propylene glycol dinitrate in the rat.

Propylene glycol dinitrate (PGDN), a major constituent of a liquid torpedo propellant, produces incoordination and impairment of balance in humans. This study was conducted to evaluate the rat as a model for PGDN-induced motor performance decrement, and to determine if direct application of PGDN onto neural tissue is a useful alternative to other routes of exposure. PGDN was injected onto the cisterna magna (ic) of adult Sprague-Dawley rats trained on the accelerod, a test of motor performance. Three groups of 13-14 male rats each received a single dose of either 5 or 10 microliters PGDN or 25 microliters sterile saline (control) while anesthetized with halothane. Accelerod performance was measured 12 min after ic injection, then hourly for 6 h, and at 24 h. Injections were evaluated using a five-stage screening criterion to eliminate grossly traumatized subjects, to verify the accuracy of the injection, and to determine the extent of mechanical damage. Eighteen out of 41 subjects passed the five-stage screen. A significant decrease in performance occurred during the first 2 h following injection of 10 microliters PGDN compared to the control and the 5-microliters groups. N significant differences were seen between the 5-microliter and control groups. These data confirm previous findings of PGDN-induced changes in human motor performance, suggesting that the rat may be a useful model for further PGDN neurobehavioral assessment. The data also indicate that ic injection may be an effective alternative to other routes of exposure for materials with appropriate chemical and biological properties if an evaluation screen is used.

Interspecies variability in propylene glycol dinitrate-induced methemoglobin formation

Interspecies variability of propylene glycol dinitrate (PGDN)-induced methemoglobin formation was studied in vitro employing erythrocytes from four separate species. The net rate of methemoglobin formation was significantly different among species with dog > guinea pig > rat ≥ human. This order of susceptibility was maintained in stroma-free hemolysates, indicating that interspecies variability was not a reflection of differences in red cell membrane permeability or intracellular transport of PGDN. The erythrocytic enzymes, catalase, superoxide dismutase, glutathione peroxidase, 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, methemoglobin reductase, and glutathione- S-transferase, were assayed by adaptation of existing methods to a centrifugal analyzer. The above enzymes were removed from hemoglobin derived from each species and the order of susceptibility to PGDN-induced methemoglobin formation remained essentially the same with dog > guinea pig > human = rat. However, the net rate of PGDN-mediated oxidation of hemoglobin to methemoglobin increased in purified hemoglobin preparations from each species. These results demonstrate that there is species variability in the net rate of PGDN-mediated methemoglobin formation. Total enzyme activity in erythrocytes may contribute to reduction in the net rate of methemoglobin formation. However, the primary determinant of the net rate of methemoglobin formation induced by PGDN appears to be the structure of each hemoglobin molecule.

Selective detector of 1,2-propylene glycol dinitrate, 1, propylene glycol mononitrate, and 2-propylene glycol mononitrate using gas chromatography/ thermal energy analyzer or liquid chromatography/ electrochemical detection

Mono- and di-nitrated propylene glycols can be separated and detected using either a gas chromatogph equipped with a nitro-specific thermal energy analyzer (g.c./t.e.a.) or a high-performance liquid chromatograph equipped with an electrochemical detector in the reductive mode (l.c./e.c.). The g.c./t.e.a. exhibits a linear range of three orders of magnitude and provides detection limits in the μg ml −1 range or lower for these three compounds. The l.c./e.c. provides a linear response over two orders of magnitude and is best suited for the determination of propylene glycol dinitrate. Trapping of these glycols on Amberlite XAD-2 resin is discussed.

Environmental chemistry of 1,2-propanediol dinitrate: azeotrope formation, photolysis and biodegradability.

Investigation of the biodegradability of 1,2-propanediol dinitrate, commonly called propylene glycol dinitrate (PGDN), the major component of the Naval torpedo fuel, Otto fuel II, has shown that this compound is resistant to biodegradation by microorganisms found in sewage sludge, a pure culture ofPseudomonas aeruginosa (previously shown to biodegrade nitroaromatic explosives), and a commercially available inoculum, Phenobac®, employed for degradation of nitrogen-containing organic wastes. However, PGDN is photolabile in ultraviolet, decomposing to pyruvic and lactic acids. In biodegradation experiments, PGDN rapidly evaporated from aqueous solutions. This unexpected volatility of PGDN, which poses a potential health hazard, was attributed to the formation of a PGDN-water azeotrope, whose presence was demonstrated by partition experiments.

The reduction of propylene glycol dinitrate and other related nitrate esters on silver electrodes

The reduction of propylene glycol dinitrate and other related nitrate esters on silver electrodes

The reduction of propylene glycol dinitrate and other related nitrate esters on silver electrodes

The electrochemical reduction of propylene glycol 1,2-dinitrate (PGDN) on solid electrodes is sensitive to the choice of the electrode material and is not detectable on many transition metals. The reduction of PGDN occurs readily at 100 mV s −1 on silver electrodes to give a peak potential that is independent of the pH, but varies with the nature of the electrolyte anion. Slower potential scan rates give a more sensitive detection of the nitrate ester, and concentrations as low as 0.5 ppm can be readily measured at 5 mV s −1 in unstirred solutions. The reduction of PGDN on silver is found to be a diffusion-controlled, irreversible reaction. Nitroglycerin (NG) and n-propyl nitrate (PN) show electrochemical responses similar to those observed for PGDN. Constant-current, exhaustive electrolysis experiments in stirred solutions show a four-electron reduction per PGDN molecule and a six-electron reduction for the NG molecule. Based upon the standard potential calculated for the reduction of simple nitrate esters: RONO 2+H 2O+2 e −→ROH+NO 2 −+OH −, these electrode reactions are characterized by high overvoltages. The transfer of the first electron involving breakage of the O−N bond is postulated to be the slow step in the reaction mechanism.

Effects of ethyleneglycol dinitrate and related compounds on ethanol preference and ethanol metabolism.

Ethanol preference in rats (ALKO strains) was studied by injecting ethyleneglycol dinitrate, glyceryl trinitrate, propyleneglycol dinitrate and ethyleneglycol mononitrate. Their effects on ethanol metabolism and on the activities of liver alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (AldDH) were also examined. All four compounds caused a marked decrease in ethanol preference. When administered 30 minutes before the injection of ethanol, all four drugs significantly delayed the disappearance of ethanol and acetaldehyde from the blood. With 150 mg/kg b.wt. of ethyleneglycol dinitrate, the blood acetaldehyde level reached 770 nmol/ml one hour after ethanol (2 g/kg b.wt.) injection. This contrasted with 30 nmol/ml for the control. Similar results were obtained with the other compounds. 3 hours after the administration of 150 mg/kg of nitrate, the liver ADH activities were inhibited by 21‐46% and the liver Ald DH activities by 32‐60%. These findings suggest that the decrease in ethanol preference and the inhibition of ethanol and acetaldehyde elimination are closely related to the decrease in liver ADH and AldDH activities in the presence of these four organic nitrates.

On the mechanism of the oxidation of human and rat hemoglobin by propylene glycol dinitrate

The kinetics and stoichiometry of the oxidation of human and rat oxy-hemoglobin (O 2Hb) by propylene glycol dinitrate (PGDN) have been investigated in vitro in both hemolysate and in intact red blood cell preparations. In hemolysate fractions from both these species, the rate constant for oxidation is nearly constant between pH 7.0 and 9.0, but it increases dramatically at lower pH values. The reaction is molecular and approximately first-order in both [PGDN] and in [O 2Hb]. The rate of oxidation is related complexly to the O 2 concentration. No oxidation occurs at zero O 2 concentration or at very high O 2 concentrations. Maximal rates are observed at O 2 concentrations where the hemoglobin is only partially saturated with O 2. The stoichiometry appears to be 1.5 hemes oxidized per ester bond broken. In whole cells, the reaction is still molecular, is approximately first-order in both reactants, and has a stoichiometry of 1.9 to 2.3 moles heme oxidized per mole of reacted ester.

High-pressure liquid-monopropellant strand combustion

Examination of the influence of dissolved gases on the state of the liquid surface during high-pressure liquid-monopropellant combustion through the use of a strand burning experiment. Liquid surface temperatures were measured, using fine-wire thermocouples, during the strand combustion of ethyl nitrate, normal propyl nitrate, and propylene glycol dinitrate at pressures up to 81 atm. These measurements were compared with the predictions of a variable-property gas-phase analysis assuming an infinite activation energy for the decomposition reaction. The state of the liquid surface was estimated using a conventional low-pressure phase equilibrium model, as well as a high-pressure version that considered the presence of dissolved combustion-product gases in the liquid phase. The high-pressure model was found to give a superior prediction of measured liquid surface temperatures. Computed total pressures required for the surface to reach its critical mixing point during strand combustion were found to be in the range from 2.15 to 4.62 times the critical pressure of the pure propellant. Computed dissolved gas concentrations at the liquid surface were in the range from 35 to 50% near the critical combustion condition.