Patent GB-627880-A (GB)
Title: Improvements in motor-fuels
IPC: C10L1/10
Filed: 1947-01-02
Abstract: Liquid motor fuel comprising hydrocarbons is stabilized (1) against gum formation produced by deterioration of the fuel, and (2) against haze formation produced by deterioration of tetra-alkyl lead compounds which may be present in the fuel, by the addition of N-tert.-butyl-N1-sec. butyl-p-phenylene diamine or N - tert. butyl - N1-isopropyl - p - phenylene diamine or both of these substances. The motor fuel need not consist entirely of hydrocarbons but may contain appreciable amounts of other combustible materials such as alcohols or ethers. Suitable hydrocarbons are cracked gasoline, straight-run gasoline, or mixtures of these, other hydrocarbon products or distillates useful as motor fuels produced by cracking or destructive distillation of substances containing carbon and hydrogen such as bituminous materials, particularly coal, peat or lignite, or hydrocarbon products produced by polymerization of unsaturated hydrocarbons such as butenes or pentenes.  In the case of motor fuels containing tetra-ethyl lead or other tetra-alkyl lead compound, the phenylene diamine derivatives can, if desired, be added to the ethyl fluid (usually a solution containing a mixture of a tetra-alkyl lead and a halogenated hydrocarbon, such as ethylene dibromide or ethylene dichloride or both) itself before the latter is added to the motor fuel.  In an example, N-tert. butyl-N1-sec. butyl-p-phenylene diamine of N-tert. butyl-N1-isopropyl-p-phenylene diamine is added to Pennsylvania cracked gasoline.  The N-tert. butyl-N1-sec. alkyl-p-phenylene diamine may be prepared by hydrogenating a mixture of N-tert. butyl-p-phenylene diamine and acetone or methyl ethyl ketone in the presence of a hydrogenation catalyst which does not promote the hydrogenation of the carbon to carbon double bonds of the benzene nucleus.  Suitable hydrogenation catalysts are copper oxide-chromium oxide or copper oxide-chromium oxide-barium oxide.  A copper oxide-chromium oxide-barium oxide catalyst may be prepared by dissolving crystals of copper nitrate, chromium nitrate and barium nitrate in water, evaporating the solution to dryness and igniting the residue to give the mixture of oxides.  Specification 600,275 is referred to.ALSO:N-tert. butyl-N1-sec. alkyl-p-phenylene diamines are prepared by hydrogenating a mixture of N-tert. butyl-p-phenylene diamine and acetone or methyl ethyl ketone in the presence of a hydrogenation catalyst which does not promote the hydrogenation of the carbon to carbon double bonds of the benzene nucleus. Suitable hydrogenation catalysts are copper oxide-chromium oxide or copper oxide-chromium oxide-barium oxide.  In examples: (1) N-tert. butyl-N1-sec. butyl-p-phenylene diamine is prepared by hydrogenating a mixture of N-tert. butyl-p-phenylene diamine and methyl ethyl ketone under elevated temperature and pressure in the presence of a copper oxide-chromium oxide-barium oxide catalyst; (2) N-tert. butyl-N1-isopropyl-p-phenylene diamine is prepared in the same manner as in (1) but using acetone instead of methyl ethyl ketone; (3) a mixture of the products of (1) and (2) is obtained by using methyl ethyl ketone and acetone simultaneously.  The N-tert. butyl-p-phenylene diamine may be prepared by coupling o-chlorobenzene diazonium chloride with N-tert. butyl aniline and hydrogenating the resulting 4-tert. butylamine-21-chloroazobenzene.ALSO:N-tert. butyl-N1-sec.  butyl-p-phenylene diamine or N-tert. butyl-N1-isopropyl-p-phenylene diamine or mixtures of these are useful as rubber antioxidants to retard the ageing of rubber.