Encyclopedia Astronautica
ClO3F/Hydyne


Perchloryl fluoride was another of the extremely reactive and toxic oxidisers tested in the United States in the late 1950's. As in the other cases, it was found that the handling problems and safety risks outweighed the performance benefits. Hydyne was a propellant blend pushed rather vigorously by the Redstone arsenal in the late 1950's, but it found little application. Hydyne, which is also known as MAF-4, is a 60 per cent, by weight, mixture of UDMH and 40 weight percent diethyltrianine (DETA).

ClO3F is a colorless gas at atmospheric pressure and ambient temperature. The liquid is water-white. Perchloryl fluoride is normally supplied in 98 per cent concentration; moisture is limited to 0.02 weight per cent maximum. It is a moderately toxic, strongly oxidising agent. The mild sweetish odour is detectable at a concentration of 10 PPM in air. Perchloryl fluoride is permanently storable in common materials of construction. It is insensitive to detonation and mechanical shock. The anhydrous material is not corrosive; however, the presence of any moisture greatly increases the corrosiveness. There are several metals which are compatible with the "wet" oxidiser. There are a number of acceptable non-metals. Conventional lubricants should not be used.

Perchloryl fluoride may be prepared by the electrolysis of a mixture of sodium perchlorate (NaClO4) and hydrochloric acid (HF). 1959 production levels were very small; and the material had only recently become available in small commercial quantities at a price of $30 per kg. The projected price for large-scale production (5 million kg/year) was $ 3.30 per kg.

The normally occurring impurities are dimethylamine, beta-aminoethyl-N-piperazine, and water. Hydyne is a clear, colourless liquid which may become discoloured on exposure to air during storage. Both UDMH and DETA have an ammoniacal odour; the odour is not so sharp or fishy as that of UDMH. Hydyne is a hygroscopic liquid which will absorb carbon dioxide and oxygen from air. It is completely miscible with water and ethanol; the solubility of gasoline and JP-4 in Hydyne are somewhat limited. It forms flammable explosive mixtures with air. Amines generally yellow during storage due to oxidation followed by polymerisation induced by air (O2) reaction is believed to form an intermediate amine oxide which undergoes polymerisation. The cost of Hydyne in 1959 was $ 0.80 per kg.

Oxidizer: ClO3F. Fuel: Hydyne. Propellant Formulation: ClO3F/Hydyne. Optimum Oxidizer to Fuel Ratio: 2.78. Temperature of Combustion: 3,290 deg K. Density: 1.22 g/cc. Oxidizer Density: 1.430 g/cc. Oxidizer Freezing Point: -146 deg C. Oxidizer Boiling Point: -47 deg C. Fuel Density: 0.860 g/cc. Fuel Freezing Point: -84 deg C. Fuel Boiling Point: 64 deg C.

Specific impulse: 285 s.
Specific impulse sea level: 285 s.

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