GB669048A - Improvements in or relating to lubricants - Google Patents

Abstract

Polytetrafluorethylene impregnated with fluorochloronaphthalene (composition by weight 46-47 per cent chlorine, 26-28 per cent fluorine, 27-29 per cent carbon and less than 1 per cent hydrogen) is employed as packing material for valves or for the gland on a stirrer shaft and is resistant to attack by corrosive chemicals. For comparison purposes, a packing material consisting of polytetrafluorethylene impregnated with a mixture of mineral lubricating oil and graphite is described. Specifications 425,920 and 430,045, [both in Group III], are referred to.ALSO:Halogenated aromatic hydrocarbons which may contain bromine and which have a fluorine content of 14-35 per cent and a chlorine content of 30-60 per cent are employed as lubricants or ingredients thereof (see Group III). The halogenated aromatic hydrocarbons may be prepared by reacting chlorine trifluoride with chlorinated naphthalene, especially according to the method of Specification 633,678. The fluorochloronaphthalene thus obtained may be further treated with bromine trifluoride, whereby substitution of bromine for chlorine, fluorine or hydrogen takes place. In the examples: (1) a reaction product of chlorine trifluoride with a chlorinated naphthalene of 49.6 per cent chlorine content is prepared according to the method of Specification 633,678, employing 1.32 parts by weight of chlorine trifluoride to 1 part of chlorinated naphthalene, an average temperature of 60 DEG C., and a reaction time of approximately 6 hours, and this product contains 46-47 per cent chlorine, 26-28 per cent fluorine, 27-29 per cent carbon and less than 1 per cent hydrogen, and (2) approximately 2 moles of bromine trifluoride are reacted with 1 mole. of hexachlorobenzene, in the absence of a solvent at room temperature over a period of 4 hours, to yield materials believed to have the empirical formula C6F5Cl5 and C6F5Cl4Br. Specifications 425,920 and 430,045, [both in Group III], also are referred to.ALSO:A lubricant, suitable for lubricating parts of equipment which are adapted for relative movement and which are exposed to attack by highly reactive chemicals, comprises one or more halogenated aromatic hydrocarbons which may contain bromine and which have a fluorine content of 14-35 per cent and a chlorine content of 30-60 per cent. Thus, the lubricant may be applied to the bearing surfaces of pumps and taps and to the gland packing materials of valves and stirrers. Furthermore, the lubricant may be applied to gaskets situated between normally stationary parts of a system which is capable of being dismantled, for example a pipeline. The lubricant may consist solely of one or more of the halogenated aromatic hydrocarbons or alternatively, particularly in extreme pressure lubrication, one or more of the halogenated aromatic hydrocarbons may be added to mineral or other lubricating oil. The halogenated aromatic hydrocarbon may be prepared by reacting chlorine trifluoride with chlorinated naphthalene, especially according to the method of Specification 633,678. A fluorochloronaphthalene thus prepared is stated to suffer no change in colour or viscosity on passing fluorine, chlorine trifluoride, or chlorine there-through for long periods of time and to be unattacked in the cold by strong acids such as hydrochloric, sulphuric or nitric acid. Lubricants resistant to many corrosive chemicals and of different viscosities may be made by blending appropriate distillation fractions of the reaction product of chlorine trifluoride and chlorinated naphthalene. The reaction product may also be treated with bromine trifluoride, whereby substitution of bromine for chlorine, fluorine or hydrogen takes place. Lubricants mentioned in the examples are (1) a reaction product of chlorine trifluoride with chlorinated naphthalene or a 5 per cent solution of such a reaction product in mineral lubricating oil; and (2) a reaction product of bromine trifluoride with hexachlorobenzene. In a test described, the lubricating properties of the mineral lubricating oil solution of (1) are compared with those of a mineral lubricating oil solution of chlorinated naphthalene. Tests are also described in which valves are packed with asbestos string or polytetrafluoroethylene, the packing being treated with fluorochloronaphthalene or a mixture of graphite and mineral lubricating oil. The use of polytetrafluoroethylene turnings mixed with fluorochloronaphthalene as the packing in the gland on a stirrer shaft to a reaction vessel containing carbon tetrachloride, hydrogen chloride and hydrogen fluoride, is also mentioned. Specification 589,923 also is referred to. The second Provisional Specification refers to the use of a lubricant comprising one or more highly or completely halogenated hydrocarbons containing fluorine and chlorine but no other halogen substituents, while the first Provisional Specification refers to the addition of such a lubricant to a lubricating oil base such as mineral oil. Specifications 425,920 and 430,045 also are referred to.