Patent GB-604410-A (GB)
Title: Improvements relating to the catalytic averaging of hydrocarbons
IPC: C07C6/10
Filed: 1946-01-02
Abstract: Hydrocarbons are catalytically averaged by reacting a fraction comprising normal paraffins of not over 6 carbon atoms, and a fraction comprising primarily normal paraffins having at least 2 more carbon atoms in the presence of a liquid catalyst comprising a substantially anhydrous mixture of hydrogen fluoride and boron fluoride, i.e. containing not more water than is present in the commercial substances as an impurity, the hydrogen fluoride constituting at least 50 mols. per cent of the total fluoride, which mixture may also contain an olefin, but no other catalytic component, the reaction being continued under a pressure to maintain the hydrogen fluoride liquid, and at a temperature and for a time, while adjusting the activity of the catalyst by means of the boron fluoride partial pressure, to produce hydrocarbons between the light and heavier fractions.  Spent catalyst may be used for de-aromatizing a hydrocarbon fraction to be submitted to the averaging.  Isoparaffins produced may be alkylated with olefins using the same catalyst.  Such a catalyst is disclosed in Specification 604,377.  The light fraction may comprise methane up to normal hexane, preferably butane or pentane or mixtures thereof.  The heavier fraction is generally above hexane, for example a gasoline, naphtha, kerosene, gas oil or other crude oil fraction or Fischer-Tropsch stock.  Preferably, 2-6 mols. of light fraction per mol. of heavier are used.  The activity of the catalyst is controlled by varying the BF3 partial pressure which may range from 5-1000 p.s.i.  Amounts of olefins up to 25 per cent of the hydrocarbons treated may be present, and act as promoter. Temperatures are from -30 to 400 DEG , preferably 20 to 212 DEG  F., and may be increased during operation.  Hydrogen fluoride may be 5-300 vol. per cent on the liquid hydrocarbons or lower in multi-stage treatment.  Pressure is preferably such as to keep all reactants in liquid phase and may be up to 1000 p.s.i.  Times vary from the order of a minute up to some hours.  After reacting, hydrocarbon and catalyst phases are separated and the latter may be recycled.  Accumulation of hydrocarbon therein is prevented by heating, for example first by flash distillation and then stripping at 250-600 DEG  F., whereby the fluorides are recovered. Alternatively, a solvent extraction of the fluorides may be effected or a material added to form a compound or complex therewith.  The hydrocarbon phase may similarly be extracted to recover fluorides. This phase may also be recycled.  Isobutane may be separated together with some fluorides and alkylated by olefin.  Aromatics in the feed are removed by treatment under the same conditions and with the same catalyst as for the averaging. In examples: (1) 7 mols. of butane per mol. of kerosene are treated at 85 DEG  C. and 250 p.s.i. to yield a gasoline; (2) a butane fraction and a de-aromatized kerosene are treated at 90 DEG  F. and 200 p.s.i.; (3) a kerosene is de-aromatized with HF + BF3 and then reacted with a pentane fraction; (4) propane and pentane are reacted to produce a gasoline.  Specifications 313,067, [Class 2 (iii)], 486,355, 559,067 and 563,280 also are referred to.