Patent GB-634602-A (GB)
Title: Catalytic isomerisation of solid hydrocarbons
IPC: C07C5/27
Filed: 1947-08-22
Abstract: Paraffin or other mineral wax is isomerized by contacting at 20-150 DEG  C. with a catalyst comprising a metal halide of the Friedel-Craft's type combined with an organic compound or a metal halide which reacts therewith to form a liquid complex or addition compound, in the presence of a cracking suppressor. Microcrystalline waxes for use in coating and like materials, rubber compounding, polishes, and moulding waxes may be obtained or liquid isomers useful as Diesel, lubricating, and spray oils. In an example, an oil obtained by treating paraffin wax is blended with a Diesel fuel to raise the cetane number.ALSO:Normally solid hydrocarbons are isomerized by contacting at 20-150 DEG  C. with a catalyst comprising a metal halide of the Friedel-Crafts' type combined with an organic compound or a metal halide which reacts therewith to form a liquid complex or addition compound, in the presence of a cracking suppressor.  The hydrocarbon charge may comprise one or more paraffins of at least 17 carbon atoms, paraffin wax, petrolatum, stop wax, ozokerite wax, wax from asphalts or bitumens, or synthetic wax obtained from carbon monoxide and hydrogen.  A suitable charge comprises paraffin of 17 to about 200 carbon atoms.  Solid hydrocarbons having an isomerizable alkyl group linked to an alicyclic or aromatic ring are included.  The catalyst may comprise aluminium chloride or bromide combined with aromatic hydrocarbons such as benzene and alkyl benzene, aromatic extracts of petroleum fractions, cyclic olefins, paraffins, olefins, halogenated paraffins, carboxylic acids, ethers, esters, e.g. isobornyl acetate, pyroboric acetate, and ethyl benzoate, organic nitro compounds, alcohols, phenols, ketones, carboxylic acid halides, organic sulphones, and generally organic compounds having a dipole moment and capable of reacting with aluminium halides.  They are made by allowing the mixture of reactants to stand at up to 150 DEG  C., generally in presence of hydrogen halide, until a liquid complex results.  They may also be obtained by contacting the metal halide with the hydrocarbon charge in the absence of a cracking suppressor, or from the isomerization of lower paraffins, the spent catalyst complex being mixed with fresh aluminium halide.  Combinations of the Friedel-Crafts' halide with other metal halide include AlCl3 in molten SbCl3, and melts of AlCl3 with halides of alkali metals or zinc.  Cracking suppressors include butanes, cycloparaffins, decahydronaphthalene, hydrindan, bi- and tri-cyclopentyl and hexyl, dicyclo alkyl-methanes and ethanes, perhydroanthracene, adamantane, spirocycloparaffins, and homologues thereof.  Hydrogen, and metals such as aluminium are also suitable.  They may be introduced with solvents or diluents.  The ratio of suppressor to hydrocarbon charge is about 0.5-10 : 1 or more, preferably 2-8 : 1.  The solid hydrocarbon may be dissolved in a solvent which may itself be the cracking suppressor.  The isomerization is effected at subatmospheric, atmospheric or super-atmospheric pressures up to about 100 atm., preferably at atmospheric up to 25 atm., at 70-110 DEG  C., and a contact-time of 15-30 minutes.  The effluent is stratified, preferably using at least two separators, the catalyst layer being recycled, after reactivation, or addition of make-up as necessary, and the other layer separated into products of diesel oil and lubricating oil range, normally solid products and unreacted hydrocarbon, which is recycled.  Processes of fractionation, solvent extraction, and fractional crystallization may, for example, be used. Micro-crystalline waxes obtained by the isomerization are used in coating, and like materials, rubber compounding, polishes, and moulding waxes.  By increase of contact time or recycling, substantially complete conversion to liquid isomers is obtained. Diesel, lubricating, and spray oils, used as components of insecticides, may be obtained.  In examples: (1) a purified wax consisting of nC25H52 is dissolved in decahydronaphthalene and contacted with AlCl3-C6H5CH3 and HCL at 100 DEG  C. for 4 hours, the solvent flashed off, and unreacted wax separated from the oil by crystallization from methyl ethyl ketone; (2) products of a similar isomerization are separated into a microcrystalline wax and liquid fractions by successive low-temperature extractions; (3) tert.-butyl chloride is used to form the complex catalyst, and the cracking suppressor is methyl cyclohexane, decahydronaphthalene or dimethylcyclopentanes; (4) a C35 wax is treated with the catalyst of (3); (5) catalysts consist of fused AlCl3, ZnCl2, KCl, and NaCl, in proportions by weight of 75 : 15 : 7.5 : 7.5; AlCl3, KCl, and NaCl in proportions 8 : 1 : 1; and AlCl3, SbCl3 in proportions 5 : 95; (6) the catalyst of (3) is employed at temperatures between 30 and 100 DEG  C.