Patent GB-435254-A (GB)
Title: Improvements in the production or recovery of polynuclear carbon compounds from bituminous substances
IPC: C10G1/08
Filed: 1934-02-08
Abstract: Unitary organic compounds containing four or more nuclei are recovered from the destructive hydrogenation products of bituminous, resinous or ligneous materials (other than mineral coal high-temperature tar), and particularly from the high-boiling fractions of these products.  The methods of recovery may be those ordinarily used in the recovery of polynuclear compounds from mineral coal high-temperature tar, e.g., cooling, precipitation, crystallization, selective dissolution and distillation, each of which may be fractional; combinations of such methods may also be used, as well as chemical methods such as fusion with caustic potash, sodamide or alkali metals, or sulphonation. Alternatively, use may be made of certain other methods described below and generally involving treatment of the destructive hydrogenation products by (1) dehydrogenation, (2) distillation with the addition of metals or condensing or polymerizing agents, (3) isomerization, or (4) removal of asphalts, pitch-forming constituents and paraffin wax, or combinations of such treatments; some of the processes involving such treatments, as described below, may be applied also to the recovery of polynuclear compounds containing four or more nuclei from the destructive hydrogenation products of mineral coal high-temperature tar, and also to the recovery of polynuclear compounds containing less than four nuclei, with or without side chains, from the destructive hydrogenation products of bituminous, resinous and ligneous materials generally.  Destructive hydrogenation.--Specified starting materials are (1) mineral coals, brown coals, peats, mineral oils, tars, graphite, wood, lignin, oil shale, mineral asphalt and the distillation or extraction products or residues of such materials and (2) recent or fossil resins or balsams or substances containing the same, such as turpentine, shellac, wood oil, copals, amber, colophony, colophony pitch, and resin oils.  Various conditions for the destructive hydrogenation of materials of class (1) are described and it is stated that the nature of the products may be varied by chemical pretreatment of the starting materials; thus, mineral coal or graphite may be treated with oxidizing agents, e.g. nitric acid, potassium chlorate, chlorine or oxygen, whereby products of more uniform character are finally obtained; if the starting material is sulphonated before or during the process, and the sulphonation products are converted into alkali metal salts, hydroxyl compounds are produced during the destructive hydrogenation; amines may be produced before or after the destructive hydrogenation or between stages thereof by treating materials containing halogen or oxygen or sulphonic groups with ammonia in the presence of a catalyst such as the compound of zinc chloride and ammonia.  Various conditions for the treatment of materials of class (2) are also described, (cf. example 22 below), and are illustrated by reference to the treatment of colophony; at 230--300 DEG  C. in the presence of copper or manganese catalysts, the carboxylic groups are reduced; at about 350 DEG  C. in the presence of iron or aluminium oxide, the carboxylic groups are split off; at higher temperatures the isopropyl groups are also split off, and at 500 DEG  C. and 150 atm. pressure, in the presence of a nickel catalyst, homologues of naphthalene are obtained; other reactions may be effected during or in connection with the destructive hydrogenation of the resinous material; thus, synthetic reactions may be promoted by the addition of condensing agents such as halogens, halides of aluminium, iron, zinc or magnesium, or boron fluoride, or by the addition of organic compounds containing halogen or oxygen; treatment of colophony with hydrogen at 280 DEG  C. and 80 atm. pressure in the presence of dilute caustic soda yields abietic acid; amines are obtained when resin acids are subjected to destructive hydrogenation at about 400 DEG  C. in the presence of ammonia under a partial pressure of 50--150 atm. in the presence of zinc chloride or ammonium chloride slag from galvanizing processes; phenanthroles may be obtained by sulphonating colophony and subjecting an alkali salt of the product to destructive hydrogenation at 340 DEG  C. in the presence of aqueous alkali and iron oxide; the resinous material may also be nitrated or oxidized before or at an intermediate stage of the destructive hydrogenation. Modification and stabilization of the destructive hydrogenation products.--(1) Modification by dehydrogenation.  The following methods of dehydrogenation are described: (a) the material is heated to 400-700 DEG  C. or, if side chains are also to be split off, from 500--1000 DEG  C., preferably in the presence of a catalyst; the latter may be silver or a metal of any of groups 2--8 of the periodic system, or a compound of such metal, for instance an oxide, sulphide, phosphate or halide; specified metals are magnesium, zinc, aluminium, silicon, vanadium, titanium, molybdenum, uranium, chromium, manganese, tungsten, iron, nickel, cobalt, rare earth metals, and metals of the platinum group; dehydrogenation may be effected in the presence of hydrogen under a total pressure of 5--200 atm. or more, but the partial pressure of hydrogen is preferably less than 50 atm. when the total pressure is 200 atm.; other gases or vapours, e.g. nitrogen, carbon monoxide or dioxide, methane or water vapour, may also be present; when side chains are to be removed, a dehydrogenation may first be effected at a relatively high temperature, e.g. 350--500 DEG  C., and the removal of side chains then effected or completed by treating the products or their fractions at 50--300 DEG  C. with agents promoting splitting, such as boron fluoride or a chloride of aluminium, titanium, or iron, with or without hydrochloric acid; alternatively, the side chains may be removed by reaction at 80--150 DEG  C. with oxidizing agents such as potassium permanganate or chromic acid; the removal of side chains may alternatively precede the dehydrogenation, which may then be effected under milder conditions; when metals of the platinum group are used as catalysts, lower temperatures may generally be applied than with the other catalysts specified; dehydrogenation may be effected in stages under increasingly severe conditions, with or without intermediate recovery of dehydrogenated products; (b) (cf. example 12 below) the destructive hydrogenation product, optionally after removal of asphaltic substances, is led at 100--700 DEG  C. and under reduced pressure over a metal of groups 3--8 of the periodic system, or an oxide, sulphide, phosphate or other compound of such a metal; specified metals are molybdenum, tungsten, chromium, uranium, rhenium, manganese and vanadium; hydrogen may be present, e.g. at a partial pressure of 5--30 mm. when the total pressure is 50--100 mm.; (c) (cf. example 13 below) the destructive hydrogenation product, optionally after a refining with sulphuric acid or an adsorbent, is heated in the presence of a finely granular metal or metal compound and an acid substance; specified metals are zinc, magnesium, titanium, silicon, lead, manganese, iron, tin, aluminium, copper, sodium, potassium, calcium, chromium, vanadium, molybdenum and tungsten; the catalysts may be applied to carriers, and in that event need not be in a finely grained state; specified acid substances, or substances producing acids under the reaction conditions, are sulphuric acid, nitric acid, phosphoric acid, sulphurous acid, formic, acetic or other carboxylic acid, sulphonic acids, chlorine, bromine and iodine or their compounds with carbon, hydrogen or ammonia, e.g. carbon tetrachloride, or easily decomposed metal halides; the acid substances and the metal or metal compound may be added simultaneously or in either order but preferably the acid substances is added before or at an early stage in the heating of the destructive hydrogenation product, and the metal or metal compound is added later; the reaction may be effected as a batch process in a vessel having an electric heating device constructed as a stirrer, but is preferably effected continuously by passing the materials through a heated pipe system; the reaction may also be effected in the vapour phase; the temperature may be 400--600 DEG  C. and atmospheric, reduced or raised pressure may be applied; (d) (cf. example 14 below) the destructive hydrogenation product is exposed to silent electric discharge, in the presence or absence of a solvent, under conditions precluding the formation of polymerization products; side chains may possibly be removed by this treatment; the discharge is produced with high-tension current of at least 50, preferably above 1000, volts and a frequency of at least 16, preferably above 1000, periods; the treatment may be effected at 29--90 DEG  C. for 2--10 hours, and any of the dehydrogenating catalysts specified above may be added; (e) the destructive hydrogenation product is led over copper at 350 DEG  C. with a limited amount of air or oxygen or (f) is treated at 150--300 DEG  C. with sulphur or similarly with another reagent which combines with hydrogen, e.g. selenium, tellurium, nitrogen oxides or dilute nitric acid; (g) dehydrogenation may also be effected by treatment with halogen followed if necessary by removal of hydrogen halide; dehydrogenation may be applied directly to the crude destructive hydrogenation products or to fractions thereof; it may also be effected during the destructive hydrogenation (or a stage thereof) by working at a relatively high temperature, e.g. 500--565 DEG  C.  (2) Modification by distillation in the presence of metals or condensing agents (cf. examples 15 and 16 below).  This treatment is analogous to dehydrogenation.  Specified metals are sodium, potassium, lithium, calcium, and zinc; specified condensing agents are aluminium chloride, zinc ch