BE406156A - - Google Patents

Description

       

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  Preparation or recovery of polycyclic carbon compounds.



   The present invention relates to the preparation or recovery of unitary polycyclic carbon compounds.



  The invention, in one respect, is aimed in particular at the production or recovery of carbonaceous compounds in which the molecule contains at least four nuclei, but it also relates to new or improved methods for producing or recovering carbonaceous compounds. polycyclic compounds containing less than four rings. These compounds can belong to the isocyclic group or to the heterocyclic group.

   As examples of such compounds there may be mentioned the alkyl-naphthalenes, naphthofluorenes, triphenylene, anthracene, alkyl-anthracenes,

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   acenaphthene, retene, pyrene, chrysene, picene., fluorene, fluorantene, truxene, naphtanthracene, naphtacene, decacyclene, diphenylene sulfide, diphenylene oxide, brasane, le carbazol, phenyl-naphthyl-carbazol, acridine and other ring systems some of which may be even more condensed as well as their homologues and their hydrides which, in their pure state, are useful as raw materials for organic syntheses.



   The industrial recovery of pure multi-ring carbon compounds, for example naphthalene, anthracene and pyrene, suitable for use in organic syntheses, apart from their synthetic preparation, has been limited until recently. day in isolating these substances from the tar resulting from the distillation of high temperature coal, which is the only raw material in which they exist in sufficient proportions and from which they are relatively easy to remove.

   The processes known to date are based on the splitting of the mixture of substances existing in coal tar into several fractions and simple products by distillation, crystallization, selective dissolution or other physical processes or by chemical processes, for example. treatment with sulfuric acid or fusion with caustic potash.



   As much as they are three-ring compounds, it is relatively easy to isolate pure substances and has been achieved quite economically on an industrial scale for years.



   But the recovery of high molecular weight compounds containing four or more cores involves considerable economic and industrial difficulties. The difficulties

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 industrial substances arise from the boiling points of these substances, which are so high that the sticky and asphaltic substances from which the substances of interest are to be distilled off decompose with the formation of coke, so that the yields of distillates containing the compounds laid with four or more cores are reduced and the recovery of these compounds is made very difficult and expensive or even practically impossible.

   Moreover, as the molecular size increases, the differences between the various compounds with respect to their solubility and the way they behave chemically diminish, so that the subsequent resolution of the distillates is much more difficult than in the case of compounds containing only up to three rings.

   As for the economic difficulties, they lie in the fact that the recovery of compounds containing four or more cores is limited to the raw material base of the tar from the distillation of coal at high temperature, which in turn is limited by many considerations. - tions relating to geographical location, quantity and price, and in this other fact that one is obliged to transform considerable quantities of interesting tar substance into pitch coke (which cannot be sold at remunerative prices only in small quantities) to recover a tiny proportion of a few thousandths of these multi-ring compounds.



   As for the products other than the tar resulting from the distillation of coal at high temperature obtained by purely thermal treatment of bituminous substances, said polycyclic compounds are only contained therein in such low proportions that their recovery, as much as it is. possible, is even more difficult and expensive.

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   However, it has been found that carbon compounds with a high molecular weight of the above-mentioned species can be prepared in a simple and inexpensive manner and in large quantities.



   The process according to the present invention, in its most important forms, utilizes the known destructive hydrogenation of crude bituminous substances.



     It may be well to point out here that wherever in the present description it is simply a question of "destructive hydrogenation" this expression is to be understood in a broad sense, including not only treatment by means of hydrogenating gases. under conditions leading to a more or less radical disintegration of the molecules of the raw materials, but also under conditions under which it is mainly a hydrogenation which takes place, or under which only some of the constituents some raw materials are attacked or degraded to a considerable extent, others remaining intact or noticeably so.



   The destructive hydrogenation of bituminous materials such as, for example, mineral coals, lignites, peat, mineral oils, tars, their products of distillation, extraction and their residues, has been carried out until today at the The effect of obtaining oils, in particular for supplying engines, lubricating oils and impregnating oils. The ultimate goal is to achieve the maximum degree of liquefaction and oil formation.

   One has already observed incidentally that such destructive hydrogenation products may also contain cyclic compounds, but only low molecular weight compounds containing up to three rings have been detected, such as for example anthracene. and carbazol, and no method was recommended

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 to collect these compounds on an industrial scale.



   Contrary to expectations, it has been found that the high boiling destructive hydrogenation products from bituminous feedstocks contain very considerable proportions of high molecular weight cyclic carbon compounds and can be removed from them at a low rate. very easy and simple way, for example by the methods which have been employed hitherto to remove compounds of this species from the tar obtained from the distillation of coal at high temperature.



   Having led to this discovery, we have further investigated the possibilities of removing from these products the interesting compounds as well as the conditions which, during the hydro-. destructive generation, lead to the production or chemical modification of these compounds. As a result of this research, several methods have been found by which the recovery of the various organic compounds from the products of destructive hydrogenation can be particularly advantageously carried out.

   These methods, which will be described in detail hereinafter, prove to be advantageous for collecting not only compounds with four or more rings but also compounds with less than four rings, and that from the raw materials precisely indicated as well. in the above that products of the destructive hydrogenation of tars from high temperature distillation *
One such process is to dilute the high-boiling crude distillates from destructive hydrogenation products with hydrogen-rich hydrocarbons, and then add a small amount of a dilute acid to them. for the effect of isolating part of the oil, which fraction is then isolated by crystallization, preferably

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 after distillation,

   polycyclic compounds with which it is enriched. This procedure is particularly advantageous for the treatment of the high boiling point residues from the destructive hydrogenation of mineral coals.



   Another process for the separation of the cyclic compounds of interest is particularly advantageous in the case of destructive hydrogenation products which contain greater or lesser proportions of asphalt or asphaltic substances. This process consists in first of all separating the asphalts or asphaltic substances from the products of destructive hydrogenation by means of solvents, precipitants or adsorbents, in subjecting to distillation the collected substances including the asphalts and isolating the polycyclic compounds from the distillates by physical or chemical methods.



   It has also been found not only that the asphalts and the corresponding substances contain the polycyclic compounds of interest but that these exist, often in even greater proportions than in the asphalts, in the portions of the hydrogenation products of the compounds. - tructive which has been freed from asphaltic and corresponding constituents.



   For the recovery of the polycyclic compounds it has been found to be advantageous in many cases to employ dehydrogenation as one of the process steps. This dehydrogenation step can be adapted to the particular circumstances of each case, for example by suitably choosing the operating conditions or by carrying it out in stages, as will be described in detail below, or it can be combined. hoe with other ways of proceeding, such as a

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 precipitation of asphaltic substances or subsequent hydrogenation of the collected polycyclic compounds, to produce hydrogenated multi-ring compounds.



   Another procedure which has some relation to dehydrogenation is to distill the destructive hydrogenation products in the presence of metals or of condensing or polymerizing agents. Likewise, this procedure will preferably be employed in combination with other treatments, such as, for example, the removal of asphaltic substances or dehydrogenation.



   There is also interest in many cases in removing paraffin waxes from destructive hydrogenation products.



   But it is not only asphalts and asphaltic substances or paraffin waxes which may tend to prevent the separation of the polycyclic compounds of interest but also the substances giving rise to pitch, which are mostly olefins with a high molecular weight. which tend to form asphalts under the influence of oxygen or heat (or both), so that their removal can be advantageous, in particular when it comes to recovering compounds with very high molecular weight.



   It will be understood from the foregoing that the methods for recovering the polycyclic compounds of interest can be varied to a large extent to meet the needs of each particular case. However, one can also influence the nature of the products recovered in other ways, for example by suitably modifying the conditions of the destructive hydrogenation or by subjecting the crude destructive hydrogenation products to a hydrogenation treatment in hydrogenation. particular conditions or to isomerization or other treatment modifying the nature of the polycyclic compounds.

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   Further research has revealed this fact that not only bituminous materials which have been relied on to date for the recovery of valuable polycyclic compounds or which have until now been mainly used as raw materials for operations. destructive hydrogenation are suitable for the purposes contemplated herein, but other raw materials can also be successfully employed.



  More particularly, it has been found that compounds of the species in question can also be obtained in a simple manner by subjecting fossil or recent resins or balms, or substances containing them, to destructive hydrogenation under moderate conditions, preferably with only slight resolution, the desired compounds being separated from the high boiling fractions of the resulting destructive hydrogenation products after they have been subjected to dehydrogenation.



   In the course of the research carried out it has also been discovered that there is an advantage in protecting liquid products from which the compounds of interest will have to be removed against undesirable influences, mainly due to the action of oxygen or air.



   A will now describe in more detail the various features of the present invention.



   As pointed out above, it has been found that polycyclic compounds containing at least four rings exist in destructive hydrogenation products and can be removed in a very easy and simple manner.



  More particularly, it has been found that compounds containing four or more cores can be produced very advantageously from bituminous substances other than tar.

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 from the distillation of hard coal at high temperature.



  Suitable raw materials for this purpose include, for example, mineral coal, lignite, peat, wood, lignin, oil shales, mineral oils, natural asphalt, tars obtained from mineral coal and lignite. by low temperature distillation, as well as their fractions and extracts and their residues from distillation, cracking and refining.



   The process according to this feature of the present invention will therefore consist in subjecting these bituminous raw materials to destructive hydrogenation and in separating by suitable methods the cyclic carbon compounds containing four or more rings from the moieties. high boiling point of reaction products.



   The discovery on which the present process is based is contrary to previous experiences with coal tars and other purely thermal transformation products of bituminous raw materials.



   As regards the tar from the distillation of coal at high temperature, it is characteristic that its chemical composition is simple compared to that of similar raw materials such as tar obtained at low temperature, tar from lignite and petroleum. . It is for this reason that it is only on the basis of coal tar that an industry has been built for the recovery of pure cyclic compounds. In the case of coal tar, pure substances defined as benzene, toluene, xylene and carbolic acid can be separated from light and medium oils by fractionation, In the case of hard coal tar oils At high boiling, crystalline substances separate from fractions boiling over very large areas.

   As the boiling point rises

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 the content of unit compounds decreases and it becomes more difficult to isolate them; for example, an average coal tar oil crystallizes about 30% solids comprising substantially only naphthalene; from heavy oil the solid deposit amounts to only 20% and from anthracene oil only 5%, the latter two only partially fractionating into pure substances by repeated crystallization. The recovery of compounds containing four cores is even more difficult, as already mentioned.



   The destructive hydrogenation products of these bituminous substances have a much more complex composition than the tar from the distillation of coal at high temperature, and in this respect they resemble oils. Not even benzene and toluene can be separated from the accompanying materials by fractionation; Lenaphthalene, anthracene and carbazol have only been found in small proportions. Because of their viscosity, which is equal to that of petroleum, high boiling point oils have heretofore been used for lubricating purposes and as motor fuels or as fuel oils, and this was required. consequence that they were completely free from solid substances.

   This is why it is very surprising that these cyclic compounds and especially those also which contain four or more rings, unlike what has been found in the case of tar from the distillation of coal at high temperature. exist in the products resulting from the destructive hydrogenation of these materials in relatively large proportions and can be isolated therefrom in pure form in a simple manner.

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   The advantages of the process according to the present invention are the following: - It starts from widely used and inexpensive raw materials. It is not necessarily limited by the many considerations which accompany the recovery of the cyclic compounds of interest from the tar from the distillation of high temperature coal.



  The products of destructive hydrogenation are high quality oils, the production of which is sufficient to make the process interesting. The recovery of cyclic compounds is not made expensive by worthless by-products. The organic substances contained in the raw materials are completely transformed into interesting compounds, namely, on the one hand, unitary polycyclic compounds that can be used for chemical purposes and, on the other hand, high quality products that can be used. can be used as fuels for engines, etc., while in accordance with known thermal destructive processes coke-like residues are formed which can only be used for their calorific value.

   Because of the high yields of destructive hydrogenation products, calculated with respect to the raw material and amounting, for example, to more than 70% of compounds which can be used in the case of coals, a relatively low yield of polycyclic compounds is sufficient to produce large quantities of these compounds.



   The disintegration of bituminous raw materials which, depending on their chemical nature, constitute or contain cyclic substances, such as for example coals, peat, lignite, cracking residues and lignite tar, can be carried out by the following process the present invention in a much more conservative manner and while protecting

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 better the aromatic structure than by the purely thermal crude recovery processes known to date.

   By varying the reaction conditions of the destructive hydrogenation, such as the pressure, the temperature, the period during which the materials are subjected to the treatment and the catalyst, the formation of the compounds can be greatly influenced. polycyclic, for example in that some molecular structures are split into lower boiling point compounds while others remain, or in that new ring systems are formed from open chain compounds, for example, by employing moderate temperatures, one obtains high molecular weight compounds containing several benzene rings, or, with the aid of iron or zinc catalysts, the oxygen content can be preserved to a large extent raw material.

   Depending on the temperature and the partial pressure of hydrogen chosen, the benzene rings can be obtained in a dehydrogenated state in the form of purely aromatic compounds or in a more or less hydrogenated state. Unlike the recovery of cyclic compounds from coal tar, which consists simply in isolating already existing substances, it is such new compounds which are often formed in this case.



   The separation of polycyclic compounds from destructive hydrogenation products is much easier than the known recovery from coal tar. The separation by distillation takes place without detrimental decomposition after the most easily decomposable asphaltic substances or other easily decomposable or easily oxidizable impurities, such as for example phenols, bases or sulfur compounds, have been removed. at least in one

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 to a large extent by prior destructive hydrogenation, this removal usually being very extensive.

   In addition to the separation and scrubbing processes hitherto applied for the treatment of coal tar, other separation processes are available, such as, for example, selective dissolution or selective precipitation. Cyclic substances, especially those containing four or more rings, which are present as aromatic compounds can be obtained in the pure state usually without chemical treatment by fractionation and crystallization from oils at the point of departure. high boil. Ring systems present as hydrides can be easily isolated by distillation since their boiling point is much lower than that of the corresponding purely aromatic compounds, allowing them to be concentrated into separate fractions.

   While by using vacuum and steam it was not possible until now in the form of purely aromatic compounds and under the most favorable circumstances to obtain polycyclic systems containing up to four nuclei in their molecule, substances con - Holding five or six cores can easily be recovered in the same way as their lower boiling point hydrides.



   Another very considerable advantage of the process according to this feature of the present invention lies in the fact that the recovered substances are obtained in a substantially pure form and in particular substantially free of impurities containing oxygen, nitrogen and other substances. sulfur, while these impurities usually exist in large quantities according to the methods known to date; they then require a complicated and difficult purification and

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 considerably in the use of products for syntheses.



   The process according to the particularity under consideration of the present invention therefore opens up to the organic chemical industry fundamentally new development possibilities for syntheses in that the already known cyclic compounds are now obtained in greater quantities, in a bulk. a purer and much cheaper state and that new ring systems can be produced in which the molecule contains up to 10 nuclei, systems which until now were inaccessible industrially or even completely unknown.



  The fact that the conservative recovery method employed leaves the side chains to a considerable extent and, if necessary, variable, offers the possibility of easily obtaining a large number of alkylated polycyclic compounds which could not be achieved until now. than by complicated syntheses, for example by the aluminum chloride process.



   Before describing in detail the various processes which have been developed for the recovery of polycyclic compounds, it is appropriate to explain how destructive hydrogenation is carried out and the other treatments which are employed as separate steps in these processes. , such as for example dehydrogenation, precipitation of asphalts, etc.



   The destructive hydrogenation of bituminous substances can be carried out in various ways by known methods. Temperatures will generally be in the range of about 300 to about 700 C. and pressures will usually be above 20 atm. and will preferably reach at least 50 atm. However, preferably much higher pressures, such as 100 or 200 or even 1,000 atm. and more.

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   Instead of hydrogen, gases containing it or capable of producing it under the reaction conditions can be used.



   The reaction will preferably be carried out using known hydrogenation catalysts, such as for example iron, tin, nickel, tungsten or molybdenum or their oxides and sulphides, and where appropriate after having previously treated bituminous substances, for example by removing the mineral constituents of coal, by destroying any alkalinity or acidity, by separating the so-called fixed carbon and particularly the decomposable or easily coking asphaltic substances from mineral oils, asphalts and cracking residues.



   The process can be carried out continuously, advantageously by introducing the bituminous substances into the reaction vessel in the liquid or molten state or in the form of a paste suitable for pumping and prepared with oil.



   It goes without saying that the conditions to be employed during the destructive hydrogenation can be tailored to the requirements of each particular case in any suitable manner.



   Thus, it will often be advantageous to choose the reaction conditions in such a way that the yield of the boiling point and high molecular weight substances is particularly high; this can be achieved, for example, in the case of mineral coal, by employing a hydrogen pressure of 200 atm. or more, a reaction temperature ordinarily not exceeding 380 to 500 ° C., a residence time for the reactants in the reaction chamber varying from about 10 to 90 minutes and employing catalysts.

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  .For example., For the treatment of mineral coal, it is possible to grind the latter finely and advantageously free it from gangue and basic constituents, which can be carried out by treatment with acid reactants, such as for example hydrochloric acid. The catalysts will advantageously be added in the state dissolved in water or in organic solvents. They can also be incorporated into the raw materials in the solid state, if necessary added to supports. The previously treated coal will then be diluted into a paste with oil and subjected to destructive hydrogenation by means of hydrogen.

   By suitably choosing the temperature, for example between 440 and 470 C. and the feed rate, for example 0.5 kg. of carbon per liter of reaction space and per hour, it is easy to carry out the reaction so that the product obtained is composed mainly of high boiling constituents.



   When it is desired to obtain destructive hydrogenation products which are particularly rich in hydrogen, it is preferable to carry out the destructive hydrogenation under conditions of temperature, pressure and reaction time such, and in the presence of suitable catalysts, by example of tungsten, molybdenum, chromium, zinc and tin or their oxides or sulphides, such that at most a slight splitting and, to the greatest extent possible, an addition of hydrogen to aromatic compounds; it is thus that one should use temperatures which are not too high, not exceeding in most cases 470 C., and a partial pressure of hydrogen as high as possible, preferably greater than 150 atm.

   The high-boiling constituents of the destructive hydrogenation products obtained in the resolution for the production of mineral spirits can also be used for the process.

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   Destructive hydrogenation products can be freed of phenols, if necessary, by treating them with alkalis, and of pyridine bases by treating them with acids.



   When it comes to treating by destructive hydrogenation oils substantially freed of hard asphalt by operating mainly under hydrogenation conditions such that no resolution of low-boiling point products or However, such that there is not considerable duplication of products of this kind, it is advantageous to operate at relatively low temperatures, usually between about 200 and 500 C., and preferably between 250 and 450 C.

   and in the presence of large amounts of catalysts, preferably those which have predominantly hydrogenating action but weak resolving action, especially groups 4 to 8 of the periodic system, such as molybdenum, chromium, tungsten and vanadium and in particular their compounds such as oxides, sulphides or halides. For this same reason it is frequently preferred that for their use the catalysts are placed rigidly in the reaction chamber. The catalytic substances can be precipitated on supports such as activated carbon, active silica or lignite semi-coke which will have been demineralized or neutralized, that is to say treated with an acid. The catalysts will preferably be used in the agglomerated state, such as pellets, tablets or cubes.

   The period during which the reactants are in contact with the catalyst at the reaction temperature will be selected such that the hydrogenation proceeds without appreciable resolution to low boiling products. This treatment results mainly in reducing phenols, sulfur compounds and bases and hydrogen-

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 remove unsaturated or aromatic compounds.



   When it is desired to prepare or recover polycyclic compounds whose molecule contains side chains, a method can be employed which is based on the discovery that polycyclic side chain compounds are primary reaction products of destructive hydrogenation and that can be obtained with good yields by using products of destructive hydrogenation of mineral carbon which will have been prepared in a manner particularly suitable for this purpose as will be explained below.

   In accordance with this peculiarity of the present invention, the destructive hydrogenation of mineral coal mixed into a paste with oil is carried out at a temperature below 440 ° C. and the feed rate is kept sufficiently. low so that the gasification is less than 13% with respect to the oil and constituents formed by the coal and the decay of the substance of the coal preferably does not exceed 90%. In addition, it is advantageous to choose the conditions hydrogenation, employing sufficient amounts of catalyst (at least 0.05%) so that the heavy oil leaving the reaction chamber contains less than 5% asphalt.



   For example, the procedure could be the following:
The mineral carbon will be finely ground and preferably freed of gangue and basic ash constituents by treating it with an acid, for example by neutralizing these basic constituents by adding a limited amount of acid. . The charcoal will then be mixed with finely ground catalyst material or it will be impregnated with a solution of the latter. The proportion of catalyst will preferably be between 0.05 and 5%. The previously treated charcoal will then be diluted into a paste

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 with oil, preferably taken from the same coal, and then subjected to destructive hydrogenation.

   The addition of catalyst can also be carried out after the charcoal has been diluted into a paste; it is also possible to add catalyst in batches at different stages of the process. In addition, different catalysts can be used. Thus, for example, to a carbon to which a compound of molybdenum or of tin has been added, after it has undergone the preliminary heating, a halogenated or sulphide compound, such as for example tetrachloride, can be added. carbon or carbon disulfide.



  The reaction temperature will advantageously be between 400 and 440 ° C. The quantity to be passed per hour through the reaction chamber will preferably be between 0.05 and 0.3 kg. of coal paste (composed of 1 part of coal and 1 part of oil) per liter of reaction space. The carbon paste brought to reaction temperature will then be conducted through the reaction chamber and the resulting product passed to a separator where a liquid level will be maintained. The temperature in this vessel will be kept only about 5 to 50 ° C below the reaction temperature, so that all of the heavy oil newly formed from the coal becomes vapor. same time as the hydrogen in the adjacent vessel.

   The product distilled into the latter consists of 30-50% constituents boiling up to 325 ° C. and 70-50% heavy oil which is free of asphalt and solid constituents.



   In some cases, by re-treating the raw materials chemically, it is even possible to achieve particular results during destructive hydrogenation.



  For example, by first treating mineral carbon or graphite with oxidizing agents, such as acid

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 nitric, potassium chlorate, chlorine or oxygen, we make the molecules more easily attackable and we can split them into relatively large and uniform molecules.



  By sulfonating the processing material either before or between the various stages of processing and converting the sulfonation products into the corresponding alkali salts it is possible to produce hydroxy compounds directly during destructive hydrogenation. By causing ammonia to act on materials containing oxygen or halogen atoms or sulfonic groups in the presence of catalysts such as the double compound zinc chloride and ammonia, compounds can be produced. amino compounds. Addition of, for example, phenols or hydrogen-rich hydrocarbons or halogenated hydrocarbons often promotes the formation of valuable compounds of high molecular weight.



   When it is desired to use as raw materials recent or fossil resins or balms or substances containing them, it is possible to use, for example, turpentine, shellac, wood oil, copals and ambrine resins, as well. as products resulting from the treatment of these substances and also residual products, such as rosin and resin oils from turpentine. Dark and impure low-grade varieties of resins or balms which are unattractive for ordinary uses, such as paints and varnishes, and the inexpensive residual products of the resin industry can be employed with advantage. , such as rosin pitch.



   A major part of these raw materials are basic chemically single or closely related substances. For example, rosin consists

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 a very complex mixture of acids, esters, anhydrides, hydrides and organic polymers, but these for the most part are derived from the same ground substance, namely, methyl-isopropyl-phenanthrene (retene). The same goes for other resins.



   The process according to this feature of the present invention is based on the discovery that from such mixtures it is easy to isolate some of these compounds, some known others unknown but almost all of great interest, and to separate them from the accompanying substances by destructive hydrogenation, especially if one operates under moderate conditions.

   It has been found that, owing to the relatively unitary structure of the raw materials, the destructive hydrogenation reaction can be regulated very precisely so that it results in one or only a few chemically unitary products, unlike hydrogen. known destructive nation of natural substances having a complicated composition, such as for example bituminous substances, during the destructive hydrogenation of which multiple reactions often occur which lead to a very complex mixture of different products.



   The advantage of this variant of the process according to the present invention for the recovery or production of valuable unit compounds, in particular of alkylated cyclic compounds and their derivatives, compared to the synthetic preparation on the basis of the products obtained from the tar. The hard coal that was available to date lies in the simplicity of the process and the minimal cost of raw materials.

   In comparison with the known treatment of vegetable resins in the resin industry by purely chemical processes, such as for example saponification or sulphination, or by purely thermal decomposition, distillation or fractional dissolution, the present process constitutes a

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 progress in that during destructive hydrogenation much more radical transformations can be achieved and that, by controlling the reaction conditions, different products can be prepared from the same raw materials; moreover, products are obtained in a purer state and with higher yields, while the by-products also obtained lend themselves to easy processing, for example as motor fuels or as lubricating oils.



   The destructive hydrogenation of these raw materials can be carried out in various ways depending on the heat stability of the aromatic compounds to be obtained and the ease with which the raw materials can be hydrogenated.



   For example, to recover the constituents of the resinous raw material which are difficult to hydrogenate, or their slightly modified ground substance, the reaction conditions during the destructive hydrogenation will be chosen so that the aromatic compounds to be recovered are modified as little as possible. while the companion substances are converted to a large extent into low molecular weight products which therefore separate or dissolve easily. One can achieve this, for example, by employing temperatures as high as possible, for example about 430 to 600 ° C., and a partial pressure of hydrogen as low as possible, for example about 20 to 100 atm., The total pressure then reaching 200 to 500 atm.



  In this case the desired cyclic compounds generally exist in the hydrogenation product in the non-hydrogenated state in the form of aromatic compounds, that is to say they are in an easily crystallizable form.



   If, on the other hand, it is desired to recover the easily hydrogenated constituents of the resinous raw materials or their basic substances, it is advantageous to use

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 as low a temperature as possible, for example about 180 to 450 ° C. and as high a hydrogen pressure as possible, for example about 150 to 60 U atm., during the destructive hydrogenation. The aromatic compounds are thus transformed into their hydrogenated derivatives. it goes without saying that also in the treatment of resins or balsams the destructive hydrogenation will preferably be carried out in the presence of catalysts, for which those which are usually employed for the destructive hydrogenation of bituminous substances are very suitable. .

   As examples of useful catalysts for the treatment of resins and balms, there may be mentioned the oxides of molybdenum, tungsten, chromium or vanadium.



   Depending on the conditions during the destructive hydrogenation of resinous substances, a more or less radical transformation of the molecules can occur. For example, it is possible to reduce the carboxylic groups of the polymerized abietic acid contained in the rosin by operating at a temperature between about 230 and 300 ° C. In the presence of suitable catalysts, such as, for example, copper. and manganese; at a temperature of about 350 ° C and in the presence of iron or aluminum oxide, the carboxylic groups are completely liberated;

   at even higher temperatures the isopropyl groups are also liberated and at a temperature of 500 C., under a hydrogen pressure of 150 atm. and in the presence of nickel catalysts, naphthalene homologues are formed by nucleus doubling. All the decay products can be obtained in the non-hydrogenated state or in a more or less hydrogenated state.



   As briefly noted above, an interesting process or step employed in the recovery of valuable polycyclic compounds is dehydrogenation.

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  This process is based on the fact that in destructive hydrogenation the cyclic compounds to be recovered are often transformed into corresponding hydrogenated compounds, the boiling point of which is usually 20 to 90 ° C. lower than those of the non-volatile compounds. hydrogenated originally present in raw materials; Thus, for example, anthracene boils at about 360 C. while perhydro-anthracene, that is to say tetradecahydro-anthracene, boils at about 275 C., and chrysene boils at about 448 C. while perhydro-chrysene boils at about 360 C.

   In addition, the constituents of raw materials which, before processing, are not distillable and easily coke, such as asphaltic substances in tars or humic substances in coals, are at the same time considerably broken down by destructive hydrogenation so that in some cases, depending on the reaction conditions, they even give rise to an additional amount of valuable polycyclic compounds. By lowering their boiling point and removing asphaltic substances, high molecular weight cyclic compounds are distillable without decomposition.

   Other compounds, such as for example those which contain oxygen, nitrogen or sulfur, can be resolved during the hydrogenation, and this makes it possible to separate them more easily from the remaining compounds.



   As a result of the dehydrogenation, the hydrogen compounds are converted or converted back to the corresponding less hydrogenated compounds, for example into purely aromatic compounds, which in themselves have a high melting point and a pronounced crystallization ability and which is easy to resolve by fractional crystallization with formation of the desired pure substances. A can in some

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 case further increase the yield of cyclic compounds by carrying out the dehydrogenation under stringent conditions such that there is release of the side chains present on the aromatic nucleus.



   The dehydrogenation can be carried out in any convenient way. However, several methods have proved to be particularly interesting, and it is these that will now be described in detail.



   One of these methods consists of heating the materials to be treated to temperatures between 4UO and 700 ° C., in particular between 4UU and 600 ° C., preferably using catalysts. If it is desired to release side chains that may be present, it will be better to heat the destructive hydrogenation product to temperatures of 500 to 1000 C., advantageously from 550 to 700 C.



   As catalysts, mention may be made of silver or the metals of groups 2 to 8 of the periodic system, such as, for example, magnesium, zinc, aluminum, silicon, titanium, tin, lead, etc. vanadium, chromium, molybdenum, tungsten, uranium, manganese, iron, nickel, cobalt, or rare earth metals, preferably in the form of their compounds, such as for example their oxides, sulphides, phosphates or halides or mixtures of such substances. These catalysts can be attached to supports, such as, for example, activated carbon, activated lignite coke, which will preferably be demineralized or neutralized by means of an acid, active silica, magnesia or blossoming lands.

   This dehydrogenation can be carried out in the presence of hydrogen under a total pressure of 5 to 200 atm. or more.



   It is advantageous to use a partial pressure of hydrogen less than 50 atm., In which case the total pressure will be

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 200 atm. Other gases or vapors, such as for example water vapor, nitrogen, carbon monoxide or methane, or gas mixtures such as for example gas with water, can also be present. . Particularly interesting results are often obtained by operating in the presence of carbon dioxide. Particularly useful catalysts for dehydrogenations in the presence of hydrogen are the oxides or sulphides of metals of groups 5 and 6 of the periodic system, optionally in admixture with other metal compounds.



   When it is desired to increase the yield of cyclic hydrocarbons by liberation of side chains which may exist, the procedure may consist in carrying out the dehydrogenation first at a relatively high temperature, such as, for example, from 350 to 550 ° C., advantageously in the presence of catalysts, such as, for example, vanadium, chromium, silicon, molybdenum, tungsten or nickel and especially their compounds, in which case no release, or only incomplete release, of the side chains occurs , after which the resulting products or their fractions are treated with substances such as for example aluminum chloride, boron fluoride, iron chloride or titanium chloride, if necessary in the presence of hydrochloric acid , at temperatures between 50 and 300 C.,

     advantageously between 80 and 200 C. There is thus a release of the side chains from the cyclic rings. This can also be achieved by treating the dehydrogenated product with potassium permanganate, chromic acid or other oxidizing agents at temperatures of 80 to 150 C.



   However, the release of the side chains by said action of chlorides or by oxidation can take place.

  <Desc / Clms Page number 27>

 before the actual dehydrogenation, which can in this case be carried out under more moderate conditions unsuitable for resolution, in particular at relatively low temperatures and with a short contact time with the catalyst.



   In many cases the recovery of high molecular weight polycyclic compounds, in particular the doubling of the dehydrogenation products to pure unitary substances, is facilitated if the dehydrogenation of the products of the destructive hydrogenation of the compounds is carried out in stages. bituminous substances.



   According to this variant of the present invention, the dehydrogenation will be carried out under conditions such that first of all only the compounds which are relatively easy to dehydrogenate are dehydrogenated; these dehydrogenated compounds can then be isolated as such, for example by crystallization.



  Dehydrogen then the remaining oil under more stringent conditions, the more difficult to dehydrogenate compounds thus being brought to the crystallizable state. If necessary, the remaining oily fraction can be subjected to dehydrogenation under even more stringent conditions in one or more further steps.



   The reaction conditions in the various dehydrogenation steps can be made more stringent, for example by raising the reaction temperature, lowering the hydrogen pressure, extending the reaction period or employing a more active catalyst. One can use more than one of these measures simultaneously.



   In the course of the catalytic dehydrogenation one can experience difficulties due to excessive local heating or the fact that substances are deposited on the surface of the catalysts, which has the effect of modifying the action of the catalyst and thus reducing inevitably the yield.

  <Desc / Clms Page number 28>

 



   It has been found that this disadvantage is avoided by effecting the dehydrogenation of the products obtained by destructive hydrogenation in the liquid phase in the presence of finely divided catalysts which are passed through the reaction zone together with the products. treat. To this end, a small amount of a finely divided catalyst, for example 0.1 to 5%, is added to the hydrogenation product. Suitable catalysts for this are those indicated above.



   One will mix the raw materials to be dehydrogenated with the finely divided catalyst and then either heat it in a gas-heated system, for example a coil, to then pass it through a heated or unheated reaction chamber, or by for example, it will be passed through an apparatus brought to the reaction temperature. It is advantageous to add the catalyst only during or after the preheating, and it can also be added fractionally and at several points of the apparatus to the material to be treated. Likewise, according to this variant, the dehydrogenation can be carried out in the presence of hydrogen, water vapor or other gases, but the hydrogen must not be present in such large quantities that it is prevents dehydrogenation.

   Pressures from 5 to 100 or 200 atm can be used. or more. The catalyst will be separated from the reaction products, for example by centrifuging, filtering or distillation, after which it can be added to new hydrogenation products which need to be dehydrogenated, if necessary after having completely or partially regenerated.



   By carrying out the catalytic dehydrogenation by one of the processes described above it has been observed that in some cases it occurs only partially and that the hydrogenated derivatives of the desired compounds which are still present can have the effect of '' prevent the separation of compounds from

  <Desc / Clms Page number 29>

 high molecular weight, especially polycyclic compounds.



   It has been found that the dehydrogenation can be carried out in a simple manner without this inconvenience and obtain the desired compounds in good yields by passing the destructive hydrogenation products (if necessary after removing the asphalts and substances therefrom. asphaltic) at elevated temperatures and under reduced pressure on metals of groups 3 to 8, in particular groups 5 and 6, of the periodic system, or on compounds of these metals.



   Before carrying out the dehydrogenation in this manner, any destructive hydrogenation products may be freed in any suitable manner from the asphalts and asphaltic substances which they contain. Specific methods for this purpose will be described in detail below.



   The dehydrogenation according to this variant of the present invention will be carried out under reduced pressure. In general, the maximum pressure will be 200 mm. and, for example, pressures of 2 to 70 mm will be employed. of mercury.



  The temperature for the dehydrogenation according to this process is usually between 100 and 700 C., advantageously between 300 and 700 C. Suitable metals of groups 3 to 8 of the periodic system or their compounds are for example molybdenum, tungsten, chromium. , uranium, rhenium, manganese and vanadium or their oxides, sulphides and phosphates. It is advantageous to carry out the dehydrogenation in the presence of hydrogen, the partial pressure of which must not however be too high, for example a partial pressure of 5 to 30 mm. for a total pressure of 50 to 100 mm.



   Another process for carrying out dehydrogenation, in particular of hydrocarbons or their derivatives and, in particular of unitary organic compounds, with good

  <Desc / Clms Page number 30>

 yields and without the formation of undesirable by-products, is to operate in the presence of metals or compounds thereof in fine grains and acidic substances, in particular acids or substances forming under the conditions of the reaction.



   The raw materials can be purified, for example by means of sulfuric acid or by destructive refining hydrogenation or using adsorbents, before dehydrogenating them.



   In order to carry out the process according to this variant of the present invention, it is possible, for example, to mix the raw materials with metals or their compounds in fine grains, preferably finely ground, then bring them to the temperature necessary for the reaction. . As catalysts for this purpose, mention may be made of metals from groups 1 to 8 of the periodic system or their compounds, such as, for example, oxides, halides and sulphides. It is particularly advantageous to use metals of the 2nd. group, from the 4th. group, from the 7th. group and group of iron, such as, for example, zinc, magnesium, titanium, silicon, lead, manganese, iron and tin, the latter preferably in the form of its compounds.

   The following metals are also suitable: aluminum, copper, sodium, potassium and calcium, and also chromium, vanadium, molybdenum and tungsten, the latter mainly in the form of their oxides and sulphides. These catalysts can also be attached to supports, in which case they need not be in a finely divided state. Suitable supports are, for example, activated silica gel, activated carbon, lignite coke which will have been treated with an acid, magnesia or fuller's earth. However, it is preferable that in any case the catalyst is in the finely divided state.



   To the raw material to which we will have added the catalyst we will then add acidic substances or

  <Desc / Clms Page number 31>

 acid-producing substances under reaction conditions. Halogens, such as chlorine, bromine or iodine, or their compounds with hydrogen, carbon or ammonia, such as carbon tetrachloride or metal compounds, can be used for this purpose. easily decomposable from these halogens. It is also possible to use other acids, such as, for example, sulfuric acid, nitric acid, phosphoric acid, sulfurous acid or sulfonic or carboxylic acids, such as, for example, formic acid or acetic acid.

   The metal or the compound acting as a catalyst can be added to the raw material before or during its preliminary heating.



  As for the acidic substances, they can be added at a high temperature, for example between 50 and 200 ° C., and at a time when the raw material already contains the metal or the metal compound. However, it has been found to be more advantageous to add the acidic substance before the start of heating or during about the first half of the temperature scale which the product is allowed to cross before it reaches temperature. reaction. In this case the metal or the metal compound can be added at the same time or, preferably, at a higher temperature, for example during the second half of the heating period, or after the heating.



   The amount of catalyst should be as low as possible. It is particularly suitable to use 0.01 to 5%, preferably less than 1%, for example 0.1% of these additional substances, relative to the weight of the raw material. It is also advantageous that the amount of halogen or other acidic substance is less than that of the metallic component. The proportion of halogenated compound to be employed depends solely on its halogen content.

  <Desc / Clms Page number 32>

 



   The reaction can be carried out in a heated vessel which will be filled, for example, with a mixture of raw material and metallic catalyst. The addition of the acid substance is then carried out at high temperature. The product can also be heated inside the container itself by means of an electric heating device, the latter being constructed, for example, in the form of a stirrer.



  However, it has been found to be more advantageous to operate the process continuously so that the catalyst remains only a short time in the reaction chamber and its activity is not adversely affected; in this way, moreover, the formation of polymerization products and the splitting of the raw materials due to local excess heating are avoided. In order to operate continuously, the material to be dehydrogenated is passed through a heated tubular system which is preferably followed by an unheated part, for example in the form of a larger vessel.

   The reaction will advantageously be carried out in the liquid phase, if necessary in the presence of gas, for example vapor, nitrogen or carbon dioxide, but it can also be carried out in the gas phase by passing the vapors over the catalysts. finely subdivided, while adding acidic substances before entering the catalyst chamber. It is advantageous to maintain a high partial pressure of raw materials. It is preferable to operate at temperatures varying from 400 to 600 ° C., the flow rate and the time during which the substances are present in the reaction chamber being such that practically no occurs. release of carbon chains by the raw material but only release of hydrogen.

   The

  <Desc / Clms Page number 33>

 The reaction can be carried out at normal pressure, at a lower or, better still, higher pressure, for example from 10 to 5u atm. or more.



   Another way of carrying out the dehydrogenation will be further described below:
It has been found that the dehydrogenation, accompanied if necessary by the release of side chains by the cyclic compounds, can be carried out by subjecting the raw materials, if necessary in the presence of solvents, to the action of discharges. dark electrics under conditions of temperature and time such that the formation of polymerization products is substantially avoided.



   For carrying out the process according to this variant of the present invention, the raw materials, in the usual Siemens ozone tubes or in a similar apparatus, are subjected to a treatment by means of dark electric discharges produced by electric currents. at high voltage, this voltage being at least 50 to 200 volts and preferably greater than 1000 volts, and preferably at high frequency. The frequency should be at least 16 periods and it is preferable that it is greater than 1000 periods per second.



   When using raw materials with a high boiling point, i.e. above 350 ° C., it is sometimes advantageous to carry out the reaction in the presence of solvents, preferably inert, such as for example lighting oil or paraffin wax, which will be better to add only during the course of the reaction. Processing time and temperature are easy to determine for each raw material by prior experience.

   As a general rule, it can be said that a decoration should not be

  <Desc / Clms Page number 34>

 Loration of the foam formed on the liquid being processed occurs, as this indicates the onset of polymerization. in all cases, the conditions must be such that the products do not undergo any increase in viscosity, i.e. the reaction must be stopped when the hydrogenation or the release of side chains (or both) only happened. The reaction usually takes place at a temperature varying from 20 to 90 ° C., which should be higher the more viscous the raw material. The duration of treatment varies from about two to ten hours.



   The treatment can also be carried out in the presence of substances having a catalytic action, for example those mentioned above.



   Dehydrogenation can also be carried out in other ways, for example by passing through copper at a temperature of 350 ° C. while adding a measured quantity of air or oxygen, or by heating with sulfur at temperatures. temperatures for example from 150 to 300 ° C. It is also possible to employ agents capable of combining with hydrogen, such as, for example, selenium, tellurium, oxides of nitrogen or dilute nitric acid. The treatment can also be carried out by direct treatment with halogen or by halogenation and evolution of hydrohalic acids, if necessary in the presence of catalysts.

   These latter processes have the advantage that they can be carried out at relatively low temperatures and that the reaction materials remain in the reaction chamber only for a short time.



   A method of treatment which has some relation to dehydrogenation in that it can be accompanied by the evolution of hydrogen is the distillation of the products.

  <Desc / Clms Page number 35>

 destructive hydrogenation in the presence of metals or condensation or polymerization agents. For this purpose, the oils are distilled under normal, supernormal or preferably reduced pressure. Suitable metals are those of groups 1 and 2 of the periodic system and among these the alkaline earth metals and especially the alkali metals are to be recommended.



  The use of metals from the bern, a group of the periodic system, such as for example iron, is generally not recommended. Sodium, potassium, lithium, calcium and zinc can be cited as suitable metals. Aluminum chloride, zinc chloride, titanium chloride, ferric chloride, stannous chloride or boron fluoride, if necessary in admixture with substances delaying the reaction such as for example zinc oxide, can be employed, for example, as such condensation or polymerization agents, which should be of the type promoting the Friedel-Crafts reaction. The metals or other agents are generally used in rather low proportions, for example from 0.1 to 10% of the weight of the oils.

   These oils can also be treated before their distillation by means of a small quantity, for example 1 to 5%, of a condensing agent, operating at ordinary or elevated temperature, for example up to 150 ° C. In this case it is not necessary to add metals or condensing or polymerizing agents during the distillation.



   Hereinafter, a description will be given of the processes which should especially be considered for the removal of paraffin waxes, asphalts and other undesirable substances contained in the materials being treated.



   In the oven, the procedure is known to separate the paraffin wax from the destructive hydrogenation products. For example

  <Desc / Clms Page number 36>

 ple, the destructive hydrogenation products or their high boiling fractions thereof can be mixed with an equal or greater amount of methyl formate and cooled to a temperature of about 0 C. The paraffin wax will solidify. is thus precipitated while the oil and the crystallizable compounds it contains are kept in solution.



  Instead of methyl formate, other solvents can be employed in which the paraffin wax is only sparingly soluble at low temperatures, for example liquid sulfur dioxide, nitro-benzene, aniline, etc. chlorinated hydrocarbons such as, for example, tetrachloroethane or trichlorethylene, or mixtures of ether and alcohol or ether and acetone, or low boiling point hydrocarbons. The wax is then separated from paraffin by filtration or centrifugation and the oil is freed from the solvent.



   Separation of asphaltic substances, by which term is meant not only hard asphalt and pitch-forming constituents, but also soft asphalts, can be effected by any known or suitable method.



   It is thus in certain cases possible to carry out a separation by filtering or by centrifuging.



    In other cases a treatment with adsorbents or a refining treatment with the usual refining agents may be sufficient. As examples of such adsorption or refining agents, there may be mentioned concentrated sulfuric acid, chloro-sulfonic acid, or salts having a condensing action, such as for example iron chloride, aluminum chloride. and zinc chloride, or fuller's earth, if necessary impregnated with sulfuric acid, bleaching earths

  <Desc / Clms Page number 37>

 or activated carbon.



   In certain cases, in particular in the case of destructive hydrogenation products which contain, in addition to asphaltic substances, a certain proportion of oils rich in hydrogen, such as for example aliphatic or cyclo-aromatic hydrocarbons, it is possible to use as precipitants of mineral acids in the diluted state, such as, for example, sulfuric acid containing 20% or spent sulfuric acid containing 30% and obtained from the refining of mineral oils.



   In general, however, it is preferable to effect the precipitation of asphaltic substances by more efficient methods, more particularly by distillation or by means of selective solvents.



   If it is desired to effect the separation by distillation, this can be accomplished by distilling the raw materials at temperatures at which virtually no decomposition occurs, until a tacky residue is obtained. Distillation can be carried out in the presence of gases, such as hydrogen or nitrogen, or vapors such as water vapor.

   The operation can be carried out at atmospheric pressure, for example at temperatures up to 350 ° C., or more advantageously, if necessary in a subsequent step, reduced pressure, for example from 10 to 15, can be employed. mm. mercury, at temperatures up to about 350 or 400 C. Care must be taken that no trace of a poisonous residue passes during the distillation, because the presence of even small quantities of this substance in the distillate can adversely affect the activity of the catalyst during subsequent catalytic treatment, and then ensure that all fractions boiling below 300 C., if necessary up to 350 C. under a pressure from 10 to 15 mm.

   mercury,

  <Desc / Clms Page number 38>

 are distilled in order to obtain the maximum yield of distillate.



   Asphaltic substances can also be freed from raw materials by means of selective solvents, such as alcohols, phenols, aniline, ketones, nitrobenzene, chlorinated organic compounds, acids, esters or liquid sulfur dioxide.



   This treatment will preferably be carried out after removing the water and the constituents with a low boiling point.



   The degree of topping of the hydrogenation products and the boiling zones of the solvents or precipitants to be employed will preferably be mutually controlled so that these solvents or precipitants can be easily removed from the products, for example by distillation. The proportion of solvent and the temperature of the treatment can be chosen so that only substances formed mainly of hard asphalt are removed from the raw materials.



   Another class of selective solvents which can be employed with great advantage leaves undissolved asphaltic substances. As very typical examples among this category of solvents, mention may be made of hydrocarbons rich in hydrogen, that is to say containing at least 13 parts of hydrogen per 100 parts of carbon, such as, for example, petroleum or petroleum distillates. destructive hydrogenation products, for example gasoline or gas oils or hydrogenated naphthalenes. Liquefied hydrocarbons which are gaseous at room temperature are particularly suitable, for example propane, mixtures of propane and ethane or butane.

  <Desc / Clms Page number 39>

 



   The products thus freed from asphaltic substances can be subjected to refining, for example by means of sulfuric acid or aluminum chloride, or by means of an adsorption agent, such as decolorizing earths. - your, before further treatment.



   In addition, the basic constituents can be removed by treatment with acids and the phenols can be removed by washing with alkaline liquids.



   In the case of destructive hydrogenation products containing solid substances, such as, for example, undecomposed carbon, inorganic constituents of the coal substance or catalysts, it is preferable to remove these substances before removing the asphaltic substances. In the case of mobile hydrogenation products this can be achieved for example by filtering or by centrifuging, and in the case of viscous products by fractional separation of the asphalt.



   The fractional precipitation of the asphalt is carried out by first precipitating only the most difficult to dissolve and most easily decomposable asphaltic substances, by adding only small amounts of precipitant, using a precipitation time short or by operating at high temperature or by employing several of these methods in combination.

   The solid substances are drawn to the bottom at the same time and can be removed together with a small amount of asphalt; by continuing the precipitation by the addition of new amounts of precipitate, by employing a longer precipitation time, or a lower temperature, or by combining several of these methods, new amounts of precipitate are obtained. asphalt or asphaltic substances in a completely soluble state and

  <Desc / Clms Page number 40>

 free from solid constituents. This second fraction of the precipitated substances, and others as needed, consist of lower molecular weight asphaltic substances which have a lower melting point and which are less readily decomposable.

   The last fractions of asphaltic substances, which can only be removed by vigorous precipitation conditions, are often oily substances with a less pronounced asphaltic character.



   The fractional precipitation can advantageously be carried out continuously, for example while the material being processed is flowing through one or more containers.



   The fractionation of asphaltic substances is also advantageous in the case of dust-free hydrogenation products, because a certain separation of the crystallizable compounds occurs and because, in the subsequent distillation of the asphaltic substances, if this is carried out , the residues from the distillation of the second and less decomposed asphalt fraction afterwards are obtained apart from the usually coked residues of the first asphalt fraction.



   A will now describe the isomerization of raw materials containing cyclic constituents belonging at least in part to the hydro-aromatic series. These raw materials can be, for example, destructive hydrogenation products of tars or mineral oils, or else destructive hydrogenation products of solid carbonaceous materials such as charcoal or lignite.

   When the raw materials do not contain aromatic constituents or contain only an insufficient proportion, the raw materials can be subjected to hydrogenation before applying the process according to this modification of the flavor.

  <Desc / Clms Page number 41>

 present invention. making this hydrogenation it can also form hydro-aromatic compounds from constituents of a heterocyclic nature, such as for example from carbazol, in which case the nucleus elements such as nitrogen, oxygen, or sulfur are usually removed, so that hydro-aromatic hydrocarbons are obtained.



   In order to carry out the isomerization, the catalysts which promote the Friedel-Crafts reaction will be used in particular, such as, for example, aluminum chloride, ferric chloride, titanium chloride or zinc chloride, which will be used from preferably in the form of salts containing their water of crystallization. It is also possible to use as catalysts boron fluoride or metal oxides or sulphides, in particular those of metals of groups 5 and 6 of the periodic system.

   The isomerization will be carried out by heating the raw materials, or more suitably fractions thereof boiling in a narrow temperature range or even fractions having a defined boiling point, at elevated temperatures between 50 and 500 C. in the presence of said catalysts, where appropriate in the presence of gases such as, for example, hydrogen, water vapor or carbon oxides. Temperatures employed for isomerization will usually vary between about 50 and about 500 C. and they should preferably be at least 100 or 120 C. up to 300 C. The treatment time will usually vary from 30 C. minutes to 4 hours, preferably 1 to 2 hours.

   During this processing the cyclic constituents of the raw material which contain 5-membered rings and side chains

  <Desc / Clms Page number 42>

 attached to it can be converted into 6-membered ring compounds. At the same time, a transformation of 6-membered nuclei into 5-membered nuclei with side chains can occur. In most cases these two types of transformation take place simultaneously, so that ultimately a balance is obtained. It is also possible to transform compounds containing both 5-membered rings and 6-membered rings into other compounds in which the 6-membered rings have been turned into 5-membered rings.

   For example, by treating carbazol with hydrogen under normal or supernormal pressure in the presence of an oxide or sulfide of a 6th metal. group of the periodic system, dicyclohexyl is obtained which, by isomerization, for example by heating to a temperature of about 450 ° C. in the presence of the oxides or sulphides of tungsten or molybdenum, is transformed into dimethyl- dicyclopentyl. By subsequent dehydrogenation, this compound is converted into dimethyl-dicyclopentadiene.

   Likewise, anthracene can be converted by hydrogenation in glacial acetic acid in the presence of a nickel catalyst to 9,10-dihydro-anthracene which, in the liquid phase, at temperatures of about 350 C. and in the presence of molybdenum sulfide under a pressure of 200 atm., simultaneously undergoes isomerization and hydrogenation to form methyl-fluorene perhydride. By hydrogenating this product in the presence of hydrogen under a pressure of 50 atm. and at a temperature of about 470 ° C. in the presence of a mixed catalyst composed of nickel sulfide and tungsten sulfide a product is obtained which is composed mainly of methyl fluorene.

  <Desc / Clms Page number 43>

 



   Having thus set forth the most important processes which it is preferable to employ in producing or recovering valuable polycyclic compounds, it is appropriate to make some general remarks on how to separate the various compounds from the products which contain them. In general, any of the methods which have hitherto been used to remove these products from the tar from the distillation of high temperature hard coal can be employed, whether they are physical or physical processes. chemical. One can use, for example, refrigeration, precipitation, crystallization, dissolution or distillation, each of these treatments being able to be fractionated, or one can employ in combination several of these processes.

   In certain cases it may be advantageous to refine the crude distillates in order to remove the resinous constituents, for example by treatment with concentrated sulfuric acid or with an aqueous solution of caustic soda or with water. medium of hydrogen under moderate conditions in the presence of refining agents, for which it is possible to use agents having adsorbent properties. The high molecular weight substances frequently crystallize in part immediately after this first coarse separation.



  The additional separation can be carried out by the usual methods, for example by distillation or additional crystallization, the latter being carried out if necessary in the presence of precipitants or solvents, or by chemical processes, for example by fusion with caustic potash, sodamide, or alkali metals, or else by sulfonation.



   Where it is desirable to separate the polycyclic compounds from the dehydrogenation products, this can also be achieved by the methods used in the treatment of gou-

  <Desc / Clms Page number 44>

 dron, for example by fractional crystallization, which will be facilitated if necessary by a preparatory or intermediate redistillation, by the use of solvents or by chemical processes based on the specific reactions of the various compounds to be recovered, such as for example a fusion with caustic potash or sulfonation.



   Thus, for example, according to the present invention, phenanthrene can be removed from a fraction distilling between 325 and 345 C., anthracene from a fraction boiling between 300 and 400 C., fluorene from a fraction boiling between 295 and 320 C., or pyrene and chrysene, which can be separated from each other by means of carbon disulfide, from the fraction boiling above 390 C. The precipitated compounds can be separated from the oil by centrifuging or filtering at moderately high, normal or low temperatures, if necessary using a diluent such as, for example, benzene, pyridine, glacial acetic acid or dioxane.



  -By crystallization from a suitable solvent or by dissolving and precipitating these substances can be obtained in a very pure state. In addition, several of these substances can be separated from fractions boiling over a larger area, the various substances being separated from each other by fractional crystallization or by treatment with different solvents or by gradual dissolution and precipitation in the process. using the same precipitant or different precipitants. When the compounds to be recovered do not crystallize at normal or lower temperatures, the unitary substances can be collected by fractional distillation, preferably in a vacuum.



   The oily fraction remaining after the separation of the crystallizable compounds can be subjected again to

  <Desc / Clms Page number 45>

 dehydrogenation either alone or together with new destructive hydrogenation products or fractions thereof, further amounts of crystallizable products often being obtained from the high boiling fractions of the products resulting.



   It is also possible to separate the crystallizable partially hydrogenated polycyclic compounds from the high-boiling point hydrogenation products and to subject only these to dehydrogenation.



   In order to isolate the unitary substances which have not been deposited by refrigeration of the distillates, the oil freed from the crystals can be treated with picric acid. One can then separate from the oil by filtering or by centrifuging the picrates thus formed. From the distillate fractions consisting of high boiling viscous constituents, as well as from the distillation residue, cyclic compounds can be isolated by treatment with selective solvents, for example by extraction with one or more. several solvents, if necessary in stages. Suitable solvents are, for example, lighting oil, carbon disulfide, alcohol, benzene or xylene.



   It has furthermore been found that when storing the distillates obtained during the treatment by distillation of the crude products of the destructive hydrogenation of bituminous substances, and in particular by vacuum distillation, and of which solid substances having excellent power crystallization separates quickly, especially distillates with a narrow boiling zone when they are of recent preparation, these distillates become discolored and soon become soiled, and the crystals and other substances which they contain or which are already trained cannot

  <Desc / Clms Page number 46>

 to be separated only with difficulty.

   It even happens that in certain fractions of the distillates the originally formed crystals disappear again and that the crystallized product cannot be recovered in the pure state in a simple manner, for example without further distillation.



   It has been found that this inconvenience is caused by even very small amounts of air or oxygen and that it can be avoided by protecting the newly obtained distillate from air or other gases containing oxygen. oxygen. The exclusion of air or oxygen can be effected by storage in an inert gas, such as, for example, nitrogen, carbon dioxide or hydrogen. It is also preferable to carry out the distillation of the products in the presence of these gases or of water vapor.



   This procedure greatly facilitates the recovery, especially from fractions with a narrow boiling zone, of easily crystallizable substances such as, for example, diphenyl, methyl-naphthalene, acenaphthalene, diphenylene oxide. , fluorene, carbazol, fluorantene, pyrene, chrysene, naphtanthracene and other substances belonging to the above-mentioned categories, as well as their counterparts and their derivatives which are partially or completely hydrogenated to the extent that they are solid at normal temperature or slightly lower, as this prevents the formation of fatty or mucilaginous substances by the action of the air.

     Thanks to this exclusion of air and oxygen the fractions remain completely intact even after months of storage and they lend themselves to a purely mechanical separation between the solid substances and the oily constituents and above all, in the pre - smells and unlike fractions of tar obtained by

  <Desc / Clms Page number 47>

 coking, the crude product contains much lower proportions of impurities, for example phenols and bases.



  Even during further processing, for example by precipitation in the presence of solvents or by crystallization, it is very important to operate according to this variant of the present invention.



   Besides the exclusion of air or oxygen, the exclusion of light during the storage of the products is also important, but it is not necessary in all cases because the action of the light causes discoloration and the formation of fatty or mucilaginous matter much more slowly.



   In what follows, the methods in which one or more of the steps or operations specifically described in the above are used will now be described in detail.



   As noted above, one such method is to dilute the destructive hydrogenation products with hydrogen-rich hydrocarbons and then add a small proportion of a dilute acid. , which has the effect of separating part of the oil, part of which the polycyclic compounds are then removed. It is preferable to use for this treatment only the high boiling fractions obtained from the crude products of destructive hydrogenation.

   As hydrocarbons rich in hydrogen, that is to say containing at least 13 parts of hydrogen per 100 parts of carbon, there may be mentioned, for example, mineral spirits, petroleum ethers, or normally gaseous hydrocarbons. such as, for example, propane or butane, or other hydrocarbons having a relatively low boiling point. After the addition of these hydrocarbons we

  <Desc / Clms Page number 48>

 will add a small amount, for example 20% by weight, of a dilute acid, for which organic acids or sulfuric acid at 20% are very suitable. From the oils which separate, the polycyclic compounds are then removed, for example by crystallization.



   Prior to crystallization, the separated oils may be subjected to fractional distillation or treated with selective solvents or suitable chemical reagents.



   By operating in this way, only a small part of the oil has to be subjected to costly fractionation, chemical treatment and crystallization operations. At the same time, increasing the proportion of compounds to be crystallized in the smallest portion of the original oil which has separated leads to an improvement in the quality of the remaining oil, because this It is thus freed from crystallizable and easily resinifiable substances, so that it can be employed as a raw material for the preparation of lubricating and impregnating oils or of very valuable fuel oils.



   Another method is, as stated above, to separate asphalts and asphalt substances from destructive hydrogenation products, to subject the separated substances to distillation and to remove polycyclic compounds from the distillates.



   This process is based on the fact that in some cases about 80% of the crystallizable polycyclic compounds which the crude products of destructive hydrogenation contain are present in the enriched state in the distillates of the asphalt or of the separated asphaltic substances. So,

  <Desc / Clms Page number 49>

 for the separation and purification, only a fraction of the quantity of oil that would have to be treated if the totality of the product of the destructive hydrogenation were treated directly by a fractional distillation carried out with care or by other costly methods.



   In addition to a simplification of the recovery of the crystallizable substances of interest, the process according to this variant of the present invention brings at the same time an improvement in the quality of the remaining oil with a view to its use as lubricating oil. fuel oil or impregnating oil because the latter remain free from deposits liable to crystallize or, for example in the case of lubricating oils, refining losses are lower. For most of the purposes for which these products are used, for example as motor fuels, lubricating oils, impregnating oils or raw materials for the chemical industry, these asphaltic substances are harmful and therefore they must be eliminated. .

   The separated asphaltic substances are usually of poor value as materials used for heating, agglomeration, road construction or isolation. Therefore, they were heretofore considered to be an undesirable by-product of destructive hydrogenation and their necessary removal was an additional expense in the production of the oils of interest, while according to this feature of the present invention they are made useful for the production of compounds of great interest.



   The distillation of the asphalt or of the separated asphaltic substances should preferably be carried out in the cones.

  <Desc / Clms Page number 50>

 The most conservative conditions in order to avoid any decomposition of heat sensitive asphaltic substances, for example by employing steam or a high degree of vacuum or both. Polycyclic compounds of interest to recover usually separate from crude asphalt distillates in readily crystallizable form. To complete the deposition or to carry out a separation into pure unitary substances, a rigorous fractionation of the crude distillate is recommended. By employing suitable solvents for the precipitation of asphaltic substances, the separation can be considerably facilitated.

   In some cases it is preferable to employ chemical processes to treat the asphalt distillates, such as for example the removal of resinous substances by treatment with concentrated sulfuric acid or a caustic alkali. .



   Another way to recover the organic compounds of interest is to subject the destructive hydrogenation products to dehydrogenation. The manner in which this process is carried out and the advantages which it provides will become clear from the explanations detailed above.



   The dehydrogenation is preferably carried out after removing any solid constituents and also, if necessary, the asphaltic substances which the destructive hydrogenation product still contains, which can be carried out in the manner specifically described above. -above.



   It is even possible in certain cases to carry out a dehydrogenation during the destructive hydrogenation itself or in one or more of its stages. For this purpose, for the destructive hydrogenation, relatively high temperatures will be employed which will usually be above 480 ° C. and which will preferably exceed 500 ° C. For example, the temperature may be between 500 and 565 ° C.

  <Desc / Clms Page number 51>

 



   In many cases it is advantageous, for the recovery of interesting polyclic compounds and in particular of high molecular weight compounds, the molecule of which contains for example up to about 10 nuclei., To combine the process described above for the precipitation compounds of interest together with asphalts and asphaltic substances with the process involving dehydrogenation.

   This is achieved by first adding hydrogen to the asphalt or asphaltic substances separated in this way by destructive hydrogenation carefully carried out at as low a temperature as possible, for example 300 to 400 C. and under high pressure, the hydrogenation product obtained then being freed of any residual asphaltic substances possibly present, if necessary in the presence of refining agents such as for example caustic alkalis or metallic sodium, then dehydrogenated and resolved by physical or chemical processes in high molecular weight pure crystalline polycyclic compounds.



   This procedure is based on the fact that asphaltic substances consist to a large extent of strongly condensed aromatic compounds with a very high molecular weight and which no longer lend themselves to distillation without decomposition. By carefully carried out destructive hydrogenation they are transformed into the corresponding hydrogenated compounds, the boiling point of which is about 100 ° C. lower than that of the non-hydrogenated compounds. At the same time, the high molecular weight fractions are resolved somewhat more. Very high molecular weight cyclic compounds can also be separated by conservative methods from hydrogenated asphaltic substances.



  This can be achieved, for example, by distilling the product while

  <Desc / Clms Page number 52>

 whole under a high vacuum and by means of large quantities of superheated steam, or by removing any residual asphaltic substances still present by the addition of precipitants or adsorbents or by treatment with relatively sulfuric acid. concentrated. The distillate or the refined product is then hydrogenated with formation of the corresponding aromatic substances by one of the processes defined above. The separation into pure chemically unitary substances is then carried out as has already been said.



   The distillation of the destructive hydrogenation products in the presence of metals or of condensing or polymerizing agents as described above is usually combined with other treatments such that the process consists of stripping. completely or partially destructive hydrogenation products or their fractions of asphalts and asphaltic substances and preferably substances not having a neutral reaction and also advantageously of any paraffin wax present, distilling the resulting product in the presence of metals or condensing or polymerizing agents and for isolating unitary compounds, in particular polycyclic, by physical or chemical processes, from the purified destructive hydrogenation products.



   The separation of asphalts and asphaltic substances will be effected in any suitable manner as described above.



   The oil thus freed of asphaltic substances can be treated additionally by means of adsorbing agents, such as bleaching earths or activated carbon,

  <Desc / Clms Page number 53>

 preferably in the presence of solvents which are unable to dissolve resinous substances in the adsorbed state, such as for example alcohol, ketones or mixtures of alcohol and benzene.



   When the oils thus purified contain paraffin wax it will be good to refrigerate them at low temperatures in the presence of a thinner. The paraffin wax which has settled on will be separated from the oil solution. This solution is freed from the solvent, the bases being preferably removed by means of acids, such as for example sulfuric acid, and of the phenols by washing with alkaline liquors, for example of a sodium hydroxide solution. caustic. If the subsequent distillation is to be carried out in the presence of metals, it has proved advantageous to remove at least the said constituents. If, however, the distillation must be carried out in the presence of condensing or polymerizing agents, the removal of acidic and basic substances is not necessary, although it is advantageous.



   When the resulting distillate is refrigerated, large quantities of crystallizable substances separate, such as, for example, anthracene, pyrene, chrysene, fluorene, picene, carbazol and diphenylene oxide.



  In order to separate these crystallizable compounds from one another it is preferable to combine fractionation with distillation. In addition, by gradually regregating the distillate, the separate crystallization of different unit substances can be effected.



   It is frequently advantageous to subject the previously treated destructive hydrogenation products to dehydrogenation before or after the distillation in the presence of metals or condensing agents. This can be done quickly.

  <Desc / Clms Page number 54>

 nière set out in detail above. When the distillation is carried out before the dehydrogenation, it may be advantageous to carry out a new distillation in the presence of metals or of condensing agents after the hydrogenation. However, the procedure may consist in carrying out the distillation under temperature conditions such that at the same time dehydrogenation of the destructive hydrogenation product occurs.

   From the oils freed from crystallized compounds it is frequently possible to isolate still further quantities of these compounds by subjecting the oils to dehydrogenation and, if necessary, to a further distillation in the manner already described.



   For the complete recovery of the unit compounds of interest from destructive hydrogenation products it is sometimes advantageous to subject the soft asphalts or asphaltic substances, when they have been removed by flocculation, to distillation by means of sweep gas. - ge, or under a high vacuum, or in these two ways at the same time, preferably in the presence of the agents already described, and to isolate from the distillate the unit compounds which it contains.



  However, the asphaltic substances can be subjected to destructive hydrogenation under mild conditions, the resulting hydrogenation product being treated as already described either alone or together with the hydrogenation products from which the hydrogenation has been separated. asphalt. It is also possible to dehydrogenate the hydrogenation product from the asphalt substances and isolate the unitary substances directly from the hydrogenation product.



   Another often very advantageous process for the recovery of cyclic compounds of interest is to remove destructive hydrogenation products as needed.

  <Desc / Clms Page number 55>

 after prior fractionation, the paraffin wax and all or part of the asphalts or asphaltic substances (or both), the compounds to be recovered being isolated from the products thus treated by physical or chemical processes and at need after dehydrogenation.



   As raw materials for this way of proceeding, there may be mentioned in particular the destructive hydrogenation products containing paraffin wax obtained from coals, tars, in particular from coal and coal tar, or from coal residues. distillation or refining of oils or tars.



   When the destructive hydrogenation products or their high boiling fractions contain not only paraffin wax but also asphalts or asphaltic substances (or both), it is preferable to remove these. last before removing the paraffin wax.



   The oil can then be subjected to a treatment by means of adsorbents, advantageously in the presence of a diluent such as alcohol, mixtures of alcohol and benzene or chlorinated hydrocarbons, preferably at high temperatures. The oil thus purified will then be freed from the paraffin wax as has already been mentioned.



   The unitary polycyclic compounds can be isolated from the oils previously treated as has just been said by fractional distillation or by crystallization or by other suitable methods.



   It is frequently advantageous to first subject the oils to dehydrogenation in the manner described above.



  Dehydrogenated products can then be separated

  <Desc / Clms Page number 56>

 unitary cyclic compounds such as anthracene, fluorene, pyrene and chrysene. In this case, too, the yield of valuable unit compounds can often be further increased by subjecting the oils freed from crystallizable compounds to a further dehydrogenation. Further quantities of crystallizable compounds can then be removed from the products thus formed.



   The procedure can also consist in separating previously treated oils, for example by distillation, from the hydrogenated derivatives of the desired compounds, the said desired compounds, then being removed by dehydrogenation.



   Another way of proceeding is based on the finding that the least volatile fraction of the destructive hydrogenation products of mineral coals or coal tar, or of their dehydrogenation products, constitute compact masses, usually hard and glassy, which it is very difficult to split, so that it is impossible to remove the unitary carbon compounds of interest therefrom by the methods known to date.



   It has been found that the pitch-forming substances contained in these masses act as dissolution promoting agents and thus prevent the recovery and particularly the crystallization of the unit compounds to a large extent, and that it is possible, by removing said pitch-forming substances from these masses, unitary carbon compounds, such as, for example, pyrene, chrysene, chrysogen, picene and their homologues and similar polycyclic carbon compounds are removed.



   The removal of pitch-forming substances can be accomplished by treating the raw materials with a solvent, for example with boiling alcohol or a mixture of alcohol and benzene, toluene or xylene, or using ketones such as acetone, or hydrocarbons

  <Desc / Clms Page number 57>

 presence of adsorbents such as fuller's earth, bleaching earths or activated carbon, This refining can also be carried out using acids, in particular strong mineral acids such as sulfuric acid or chloro acid sulfonic acid, or salts having a condensing action, such as iron chloride, aluminum chloride and zinc chloride, preferably in the presence of solvents.



   From these purified masses it is possible to remove by known methods substances having unit boiling or melting points.



   Substances adsorbed by the adsorbents can be separated from solid refining agents using solvents, such as carbon disulfide, carbon tetrachloride or trichlorethylene. After removal of the solvent, valuable resins remain which can be used as such as artificial resins or as insulating compositions or which can be added to natural or synthetic resins.



   In some cases it has been found to be advantageous to operate by separating the asphalt from mineral oils, subjecting the oils to destructive hydrogenation under predominantly hydrogenating conditions and removing the compounds of interest from the hydrogenation products. in particular polycyclic, by physical or chemical processes.



  The remaining liquid fraction from the separation can be dehydrogenated if necessary, other unitary substances being removed by physical or chemical methods from the resulting products. The liquid substances which remain are of the nature of medium or heavy oils and can be transformed into gasoline, for example by cracking or by destructive hydrogenation.

  <Desc / Clms Page number 58>

 



   According to this variant of the present invention, the asphalt, preferably exclusively hard asphalt, is first separated from said substances. This can be achieved by the usual methods.



   The oils thus roughly freed from the hard asphalt will then be treated with hydrogen in the presence of catalysts. This destructive hydrogenation must be carried out under predominantly hydrogenating conditions as has been described in detail above.



   From the products resulting from the destructive hydrogenation, where appropriate after hydrogenation and preferably after having first split them into fractions, the unit compounds, in particular polycyclic, will be removed by the processes used in the treatment of tars, by for example by rigorous fractionation by distillation or fractional crystallization, which can be facilitated by preliminary or intermediate redistillation or by the use of solvents or by chemical processes, for example by melting with caustic potash or by sulfonation.



   The oils freed from said compounds can then be dehydrogenated. Further amounts of unit compounds can be removed from the resulting dehydrogenated products as already described.



   A particular process has been found which is of particular interest in the treatment of raw materials containing cyclic constituents belonging at least in part to the hydro-aromatic series. These raw materials may first be heated, in the presence of catalysts capable of effecting isomerization, to temperatures high enough to produce such isomerization, as explained in detail above, the resulting products being. then

  <Desc / Clms Page number 59>

 subjected to dehydrogenation which in some cases may be accompanied by removal of side chains from the molecules.



   When it comes to preparing polycyclic compounds having side chains it is preferable to employ destructive hydrogenation as described above as suitable for this purpose, after which the oil can be subjected. Heavy duty obtained, if necessary after treatment with an adsorbent agent, to dehydrogenation as described. The unit polycyclic compounds will then be separated from the resulting products in the usual manner. The remaining oil can be added to the product consisting of oil, carbon and catalyst which is withdrawn from the separator. This mixture can be centrifuged or filtered, if necessary after adding a diluent or a small amount of an asphalt precipitant.

   After the solid constituents have been partially or completely removed, the oil can be used to dissolve new coal into pulp.



   By adding a sufficient quantity of a precipitant to the asphalt, it is also possible to almost completely remove the product from the separator of the solid constituents, asphalts and resins, then, if necessary after having it. treated with an adsorbent, the resulting oil will be dehydrogenated, optionally at the same time as the distilled heavy oil already described. From the resulting products the unit compounds are then removed.



   It has been found that there is an advantage, in the process according to this variant of the present invention, to regulate the rate of supply of carbon in the destructive hydrogenation phase in such a way that, this rate remaining within the above limits above defined, the proportion of constituents

  <Desc / Clms Page number 60>

 boiling above 3250C. present in the destructive hydrogenation product corresponds to the quantity of unitary substances to be separated. In this way, a sufficient quantity of oil is always available to dissolve new coal into paste.

   On the other hand, the heavy oil fraction can be increased by increasing the feed rate, the dehydrogenated oil being treated, after removing the polycyclic compounds, in another reaction vessel to obtain. of gasoline and medium oil by destructive catalytic hydrogenation.



   In the processes described above, difficulties are sometimes encountered when it is desired to obtain partially or completely hydrogenated cyclic compounds.



   This is particularly due to the fact that completely or partially hydrogenated cyclic compounds dissolve very easily in each other and often also form mixtures at constant boiling point, which makes it difficult or even all-out. makes it impossible to separate by crystallization or fractional distillation the various hydrogenated cyclic compounds from the accompanying substances.



   When it is desired to obtain cyclic compounds which are only partially hydrogenated, there is further the disadvantage that the products of destructive hydrogenation in many cases contain only completely hydrogenated compounds, so that it is necessary to carry out dehydrogenation. This is difficult to carry out so that it ceases exactly to the desired degree, and it may happen that some of the substances to be obtained are not sufficiently dehydrogenated, others are too dehydrogenated. in some cases even being transformed into cyclic compounds

  <Desc / Clms Page number 61>

 non-hydrogenated corresponding.



   It has been found that from destructive hydrogenation products of bituminous substances such as, for example, coals, tars, mineral oils or their fractions or residues, cyclic compounds with molecular weight can be obtained in a simple manner. high fully or partially hydrogenated by dehydrogenating the raw materials or their high boiling fractions, separating from the resulting reaction product, by physical or chemical processes, unitary cyclic compounds or mixtures of only a few of these compounds and subjecting the products thus obtained to hydrogenation in order to form the desired fully or partially hydrogenated compounds.



   According to this variant of the present invention, any destructive hydrogenation products, especially their high boiling fractions, can be employed.



  In order to obtain a particularly good yield of the desired hydrogenated cyclic compounds, it is advantageous to carry out the destructive hydrogenation of the bituminous substances under conditions of temperature, pressure and reaction time such and in the presence of suitable catalysts such as at most only a slight doubling of the raw material takes place, but there is as considerable an attachment as possible of hydrogen to the aromatic compounds present in the raw materials or formed during the reaction, more specifically described above.



   Before continuing the treatment, the solid constituents which they may contain and preferably also the asphaltic substances are separated from the destructive hydrogenation products or their high-boiling fractions.

  <Desc / Clms Page number 62>

 



   The high boiling fractions of the destructive hydrogenation products, which contain the cyclic compounds mainly in the form of their hydrogenated derivatives, are then subjected to dehydrogenation, preferably after being subdivided. in fractions boiling in narrow temperature zones, the hydrogenated derivatives of the cyclic compounds being thus transformed into the corresponding non-hydrogenated fundamental substances.



   The high molecular weight cyclic compounds are present in the resulting dehydrogenation products in readily crystallizable form. One can remove said compounds therefrom by the usual methods.



  * The non-hydrogenated substances thus obtained are then subjected to hydrogenation to form the desired hydrogenated derivatives. This hydrogenation can be carried out in a known manner. This will be carried out under conditions such that the desired degree of hydrogenation is obtained without any appreciable disintegration occurring with the formation of lower molecular weight compounds. For example, temperatures varying from 100 to 300 ° C. can be used with hydrogen at a pressure of 50 to 500 atm. or more in the presence of one of the known hydrogenation catalysts, such as for example a 6th metal. group of the periodic system or nickel or cobalt or a compound thereof, especially a sulfide.

   It is easy to determine, if necessary by preliminary experience, the suitable conditions with respect to pressure and temperature. For example, when a nickel catalyst is employed, phenanthrene can be converted to tetrahydro-phenanthrene under a pressure of 90 atm. at a temperature of 260 C., and the tetrahydro-phenanthrene can be converted into octohydro-phenanthrene

  <Desc / Clms Page number 63>

 threne under a pressure of 87 atm., at a temperature of 175 C.



   When preparing the polycyclic compounds of interest from resins or balms, the conditions to be employed during the destructive hydrogenation will be apparent from the detailed explanations given above. In this case also many other reactions can occur or can be carried out during or in connection with the destructive hydrogenation. For example, synthetic reactions are frequently possible such as for example the isomerization of cyclohexane rings with formation of methyl-cyclopentane rings, ring closure between aliphatic side chains or condensation of several molecules to form compounds. very condensed.

   One will preferably promote these reactions by the presence of catalysts having a condensing action, such as, for example, halogens, or halides of aluminum, iron, zinc, magnesium or boron fluoride. In these reactions, it is also possible to cause organic compounds, for example compounds containing halogen or oxygen, to act on the molecules formed by the resins.



   In addition, before or during the destructive hydrogenation, or between the various stages of the latter when it comprises several of them, it is possible to cause the substances to be treated to act on agents other than the hydrogen used for the hydrogen. destructive generation and catalysts that are usually used at the same time. In this way it is easy to carry out reactions which do not normally occur in destructive hydrogenations and thus interesting derivatives of the compounds contained in the raw materials or of their basic substances can be obtained.

  <Desc / Clms Page number 64>

 



   For example, from the polymerized abietic acid contained in rosin, most of the abietic acid is removed as such by treatment with a dilute solution of caustic soda, operating at a temperature. of 280 C. under a hydrogen pressure of 80 atm.



   Amino derivatives are obtained during the destructive hydrogenation of resin acids in the presence of ammonia at a partial pressure of about 50 to 150 atm., At temperatures of about 400 ° C. employing zinc ammoniacal chloride or ammoniacal slag as a catalyst which remains after fire galvanizing.



   Other derivatives can be obtained by suitable chemical treatment of the raw materials before the destructive hydrogenation or during the various stages, for example by sulfonation, nitration or oxidation. For example, phenanthrols can be obtained by the sulfonation of rosin, the preparation of the alkaline metal salt and the destructive hydrogenation of the latter at a temperature of 340 ° C. in the presence of an aqueous alkali and. iron oxide.



   It will readily be understood from the foregoing that it is not necessary in accordance with the present invention to employ destructive hydrogenation exclusively for the production of valuable polycyclic compounds. It is often very useful to combine the process according to the present invention with the destructive hydrogenation customary for the production of oils for use in fueling engines, impregnation, lubrication and for the like. .

   This can be achieved by employing for the preparation of the polycyclic compounds of interest only those fractions of the destructive hydrogenation products which are particularly suitable for this purpose, the other fractions being treated in the usual manner for the preparation. production of gasoline, lubricating oils,

  <Desc / Clms Page number 65>

 etc. It goes without saying that only destructive hydrogenation products or their fractions which contain cyclic constituents and whose boiling points are at least 150 ° C. and preferably at least 250 ° C. and preferably at least 250 ° C. are only suitable for the purposes of the present invention. 280 C.



   The present invention will be described more fully with the aid of a few specific examples, but it should be understood that it is in no way limited to these examples.



   When, in the examples below, it is simply a question of parts, they will always be considered to be weights.



   One may notice that Examples 1 and 2 illustrate the production of compounds containing at least four cores from destructive hydrogenation products of bituminous materials. Example 3 is given in connection with the treatment of destructive hydrogenation products by means of hydrogen-rich hydrocarbons and by means of acids, and the obtaining of polycyclic compounds from the separated oils. Example 4 explains the separation of asphaltic substances and their further processing in order to obtain the polycyclic compounds. Examples 5, 6, 7, 8 and 9 illustrate the use of the dehydrogenation phase in general, while Example 10 explains the dehydrogenation step by step. Example 11 is given in connection with the combination of the separation of asphaltic substances with the dehydrogenation.

   Dehydrogenation in the liquid phase using catalysts suspended in the material being treated is illustrated by Example 12, dehydrogenation in vacuum by Example 13, in the presence of acidic substances by Example 14, and by means of obscure electric discharges by Example 15.

  <Desc / Clms Page number 66>

 



  Examples 16 and 17 are given in connection with the distillation in the presence of metals or of condensing or polymerizing agents.



  Obtaining interesting compounds after the removal of the paraffin wax is illustrated by Example 18, while Example 19 relates to the removal of the pitch-forming constituents prior to the recovery of the polycyclic compounds. Example 20 explains the removal of asphaltic substances followed by destructive hydrogenation under predominantly hydrogenating conditions, after which the polycyclic compounds are removed. Example 21 is an illustration of the process comprising isomerization followed by dehydrogenation. Destructive hydrogenation under conditions particularly suitable for the production of compounds containing side chains is explained by Example 22, and the production of aromatic compounds by Example 23.

   Example 24 relates to the production of polycyclic compounds from resins or balms. Examples 25, 26 and 27 illustrate the influence of air or other gases containing free oxygen on the separation of polycyclic compounds from the liquids which contain them.



   However, it should be noted that these examples describe not only the features which will be specifically discussed in what follows and which are considered to be the most important, but also many other features which will emerge from a careful study of these examples. Example 1: Impregnate 20 parts of ground flaming coal with a quantity of hydrochloric acid sufficient to neutralize their alkalinity, dry it and crush it into a very consistent paste with 10 parts of molten soft pitch (obtained from a hydrogenation product of a mineral carbon) having a solidification point of 50 C. in the presence of 1 part

  <Desc / Clms Page number 67>

 of a composition based on ferric oxide for the purification of gases impregnated with a solution of ammonium molybdate, the temperature being 150 C.

   By means of a pump and at a temperature of 15U "C. Pass this paste through a short and wide pipe through a pressure-tight reaction vessel fitted with a stirrer and hydrogenate it in this vessel at a temperature. temperature of 500 ° C. with hydrogen under a pressure of 160 atm., the reaction materials remaining for 20 minutes in the reaction chamber.



  After having removed by centrifuging the mineral and carbonaceous constituents, distill the product of hydrogenation until hard pitch is obtained by means of superheated steam and under reduced pressure, the oil which passes above 250 C . under a pressure of 50 mm. of mercury being distilled again under the same pressure. When the boiling fraction is left to stand between 250 and 280 ° C. under this pressure, the pyrene separates at a rate of 1% of the carbon used.



  After pressing and washing with a little benzene and pyridine, it is practically pure. Example 2: Mix 1000 parts of a lignite generator tar that has been topped up to a temperature of 3000C. with 80 parts of a composition for the purification of gases based on ferric oxide that will have been impregnated with a solution of 2 parts of ammonium molybdate, dry this mixture and then treat it at a temperature of 460 ° C. by means of hydrogen at a pressure of 150 atm, the time during which the reactants remain in the reaction chamber being 6U minutes.

   Subjecting the reaction product to fractionation carried out with care in a vacuum. n leave to stand for 5 days at room temperature

  <Desc / Clms Page number 68>

 ordinary fraction boiling at a temperature of 260-270 C. under a pressure of 50 mm. of mercury it gives up crystals which, after recrystallization from benzene, constitute pure pyrene. example 3: Dilute 10U kg. of a distillate boiling above 330 C. obtained from a destructive hydrogenation product of mineral coal with 40 kg. of crude gasoline having a specific weight of 0.70 and thoroughly mix the whole with 20 kg. a spent sulfuric acid grading 10% and coming from mineral oil refining operations. It immediately separates 30 kg. heavy oil.

   Collect this oil, neutralize it by washing with a caustic alkali solution and subject it to fractional vacuum distillation. The fraction boiling between 240 and 270 C. under a pressure of 5U mm. of mercury gives up after cooling about 8 kg. of compact crystals from which a 95% pyrene is obtained after centrifugation and crystallization from benzene.



     Example 41 At 100 kg. a distillation residue (obtained by distilling up to a temperature of 28U "C. a destructive hydrogenation product of mineral carbon) having a Kramer-Sarnow softening point of 35 ° C. and containing 25% of carbonaceous constituents and insoluble minerals, add at a temperature of 200 C. 20 kg of a kerosene fraction having a boiling point of between 160 and 230 C. After approximately 1 hour, 40 kg are deposited. hard asphalt and insoluble constituents Collect the oil which floats in. After about 3 to 5 hours 40 kg of soft asphalt free of insoluble constituents separates out, leaving 40 kg d 'a brown-red mobile oil poor in asphalt.

   Recover the precipitant of these three fractions by

  <Desc / Clms Page number 69>

 blowing by means of steam. Distill under a pressure of 10 mm. of mercury and while employing an equal amount of superheated steam the soft asphalt free of insoluble constituents. One gets 30 kg. of a high boiling point distillate. By letting it stand, it separates crystals which consist of chrysene, pyrene, carbazol and fluorene. Pure pyrene is obtained by crystallization from benzene.



   Example 5: After having added to mineral carbon tar pitch 3% of a composition for the purification of gases based on ferric oxide which has been impregnated with 0.1% (relative to the pitch) of ammonium molybdate, pump it back continuously by means of a pump through a container stable at high pressures and treat it there for 10 minutes at a temperature of 470 C. under a pressure of hy- drogen of 200 atm. The resulting reaction product is steam-distilled in a vacuum.

   Collect separately the fraction having a boiling point between 230 and 380 C. under a pressure of 50 mm. mercury and dehydrogenate it for 5 minutes at a temperature of 510 C. under a hydrogen pressure of 30 atm. in the presence of 5% of composition for the purification of gases based on ferric oxide and 0.3% of nickel oxide.



   Then fractionate the dehydrogenation product in a vacuum by column distillation. Subdivide the various fractions into their compounds crystallized by fractional crystallization in known manner, if necessary with redistillation; for example, dissolving in 70% benzene the fraction which passes at a temperature of 420 to 460 C. under atmospheric pressure. By cooling this fraction gives up with a yield of 20% of its weight of chrysene

  <Desc / Clms Page number 70>

 almost pure mixed with a little phenyl-naphthyl-carbazol.



   Example 6: Impregnate ground flaming coal with a quantity of hydrochloric acid sufficient to neutralize the alkalinity of its mineral constituents, dry it and grind it into a very consistent paste with soft pitch of molten mineral coal tar having a point of melting at 50 C. in the presence of a composition for the purification of gases based on ferric oxide, the ratio being 20: 10: 1 and the temperature 150 C. Push this paste at a temperature of 150 C. by means of a pump through a short and wide pipe through a pressure-stable vessel fitted with an agitator and subject therein to hydrogenation at a temperature of 470 ° C. by means of hydrogen under a pressure of 250 atm., the residence time of the reactants in the reaction chamber being 20 minutes.

   Remove by centrifuging the mineral and carbon constituents contained in the hydrogenation product and distill off to a temperature of 280 ° C. the most volatile fraction.



  Stir the remaining distillation residue with 50% mineral spirits, which has the effect of precipitating the asphaltic substances contained therein and making them removable. Then carefully subject the oil to fractional vacuum distillation using a column and dehydrogenate the various fractions separately.

   The fraction which passes at a temperature of 250 to 270 ° C. under a pressure of 50 mm will be dehydrated. of mercury by passing it to a temperature of 380 "C. with 40 m3 of air per 100 kg. of oil on a catalyst composed of 50% iron oxide, 20% alumina and 30% copper , or by heating it with 20% flower sulfur for 2 hours at a temperature of 300 C.

  <Desc / Clms Page number 71>

 or by passing it as described in Example 5, at a temperature of 510 C. at the same time as hydrogen under a partial pressure of 30 atm. on the catalyst described in said example. After cooling to a temperature of 10 ° C., the dehydrogenation product gives up almost pure pyrene.



   Example 7: Heat in an autoclave, at a temperature of 550 ° C. and under an initial hydrogen pressure of 10 atm. (measured at normal temperature) a fraction boiling at a temperature of 230 to 300 C., which will have been obtained by the destructive hydrogenation of mineral carbon, in the presence of a catalyst consisting of nickel sulphide and tungsten sulfide. By distilling off the reaction product, a fraction boiling at a temperature between 295 and 320 ° C. is isolated which, after cooling, leaves a product composed mainly of fluorene. Clean the oil from the oil by centrifuging and purify it further by crystallization from alcohol or with an alkaline-metallic compound.



     Example 8 Dehydrogenate, as described in Example 7, a heavy oil fraction boiling at a temperature above 300 ° C. and obtained by the destructive hydrogenation of a mineral carbon. Distill the hydrogenation product with formation of coke. Extract the resinous oil, which boils at a temperature above 400 ° C., using carbon disulphide, remove the carbon disulphide from the extract and crystallize the residue from methanol; thus obtains pure pyrene.

   Extract the portion insoluble in carbon disulfide while hot in glacial acetic acid and evaporate the extract; we thus obtain a mixture composed of

  <Desc / Clms Page number 72>

 chrysene and a. little picene, which can be crystallized out from glacial acetic acid or cumene.



   Example 9: Triturate into a paste 100 parts of mineral carbon having a carbon content of 82% and which will have been previously treated with dilute sulfuric acid in order to neutralize the alkaline mineral constituents with 40 parts. of topped mineral carbon tar and 5 parts of a powder catalyst composed of 98% of a mixture of iron oxide and alumina and 2% of molybdenum sulphide.



   Push back this paste without interruption, at the same time as 0.7 m3 of hydrogen per kg. of dough, through three high pressure-stable receptacles arranged one after the other and the first two of which will be maintained under a pressure of 200 atm. and at a temperature of 460 C. while the third will be under a pressure of 100 atm. and at a temperature of 510? C.



   It is in the first two vessels that the fixation of hydrogen and the disintegration of the carbonaceous substance into distillable oils will take place, while the hydrogenation, mainly of the oily constituents with boiling point. high, occurs in the third. Distillable oils will be removed from the reaction product by steam distillation in a vacuum. The fraction boiling at a temperature between 240 and 270 C. under a pressure of 50 mm. of mercury, after diluting it with 10% ligroin and allowing it to stand for three days at a temperature of 10 ° C., it separates from pyrene which is practically pure after a single recrystallization from an equal amount of pyridine bases.



   Example 10: Triturate into a paste with 40 parts of topped mineral carbon tar and 5 parts of a catalyst

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 with pulverized ferro-molybdenum 100 parts of mineral coal having a carbon content of 82% which will have been previously treated with dilute sulfuric acid in order to neutralize the alkaline mineral constituents. Uninterrupted delivery of this dough, at the same time as 0.7 m of hydrogen per kilogram of dough, through three stable high-pressure vessels arranged one after the other and the first two of which are maintained at a temperature of 460 C. and under a pressure of 200 atm. while the third is maintained at a temperature of 510 ° C. and under a pressure of 100 atm.



   Hydrogen fixation occurs and the carbonaceous substance disintegrates into distillable oils in the first two vessels, while in addition to the release of the CC bonds the hydrogenation mainly of the oily fractions with point of. high boiling occurs in the third. Distillable oils will be removed from the reaction product by steam distillation under reduced pressure. From the fraction boiling between 170 and 270 "C. under a pressure of 50 mm. Of mercury, after having been diluted with 10% ligroin and left to stand for three days at a temperature of 0 C. it separates pyrene and carbazol, the latter can be separated by filtration and crystallization from an equal amount of pyridine.



   After removing the ligroin from the remaining oil, it will be dehydrogenated again at a temperature of 550 ° C. under a hydrogen pressure of 20 atm. and then subjected to fractional distillation. The distillate leaves behind crystals from which pure anthracene will be obtained by crystallization from benzene and pyridine.



   Example 11: Subjecting the soft asphalt fraction obtained according to Example 4 to a destructive hydrogenation at

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 a temperature of 390 C. and under a pressure of 230 atm. in the presence of a ferro-molybdenum catalyst. Rid the resulting product of minute amounts of asphalt it contains by steam distilling it under high vacuum.



  Pass the distillate in the vapor state at the same time as steam at a temperature of 560 C. over a catalyst composed of zinc oxide, alumina and molybdenum oxide.



  Dissolve 10% picric acid in the condensed reaction product. On cooling, a picrate separates in the form of long red needles from which, by decomposition by means of ammonia and recrystallization from alcohol, a hydrocarbon is obtained having the formula, according to its analysis, C18H13.



   Example 12: Heat to a temperature of 500 C. and under a total pressure of 120 atm. an oil boiling above 325 ° C. obtained by the destructive catalytic hydrogenation of mineral carbon together with hydrogen in a coil; to the raw material thus heated add 2% of a catalyst composed of small lignite coke which will have been treated with hydrochloric acid, washed and impregnated with a solution of ammonium molybdate so that it contains 2% of its weight of molybdic acid, this mixture then being discharged without interruption through the reaction chamber maintained under the same temperature and pressure conditions.

   Cool the resulting product, relieve the pressure, remove the catalyst by centrifugation and subject the remainder to carefully carried out fractional distillation. The fraction boiling below a temperature of 200 ° C. contains a high proportion of aromatic hydrocarbons, for example toluene and xylene.



  From the fraction boiling at a temperature between 200 and 27500. it will be drawn by leaving it to stand for about 15%

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 crude naphthalene (the corresponding fraction of the raw material containing less than 0.5%). The fraction which boils at temperatures between 275 and 380 C., left to itself, provides about 25% crude anthracene (the raw material containing less than 1%). Split the crude anthracene by crystallization from alcohol into pure anthracene, phenanthrene, acenaphthene and methylated naphthalenes. The oil freed from crude anthracene furnishes, by fusion with caustic potash, about 15% fluorene (the raw material contained less than 1%).

   The residue boiling at temperatures above 300 ° C. is distilled until coking, the proportion of coke remaining being about 20%.



  From the distillate about 35% pyrene was extracted by carbon disulfide extraction, while about 5% of the remaining oil was removed by dissolution with glacial acetic acid. The remaining oily fractions can be subjected to further hydrogenation after stripping them of solid aromatic hydrocarbons.



   Example 13: Free from its solid constituents, by centrifuging, a muddy residue resulting from the destructive hydrogenation of mineral coal, remove the asphalt if necessary using lighting oil, then heat it to a temperature of 280 C. in a heater. After this preliminary heating, pass the mass through a reaction chamber loaded with a catalyst comprising molybdenum, zinc and magnesium and in which a temperature of 500 ° C. is maintained, a pressure of hydrogen. varying from 30 to 40 mm. and a total pressure of 70 mm. of mercury. The feeding rate is 0.15 kg. of oil per liter of oven capacity and per hour. Subject the resulting dehydrogenation product to fractional condensation in a separator which will also be under reduced hydrogen pressure.

   After allowing the fractions to stand for a

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 considerable time about 20% of crystals are separated from it, consisting mainly of pyrene, chrysene, anthracene, acenaphthene, naphtanthracene, picene and methyl-naphthalenes, which will be separated from mother liquor by pressing and which will be purified by fractional crystallization from mixtures of alcohol and benzene. By adding a solution of picric acid to the mother liquor, about 5% of crystalline compounds are obtained in the form of picrates which can be decomposed with ammonia to form hydrocarbons which can be separated from each other. others by fractional crystallization.



   Example 14: Distill under a pressure of 15 mm. of mercury in the presence of a catalyst containing molybdenum an oil obtained by the destructive hydrogenation of a mineral carbon at a temperature of 460 C. and under a pressure of 250 atm., and isolate the fraction which boils at temperatures between 180 and 325 C. This fraction contains 2% of crystallizable substances which will be separated by diluting it with a mixture of ether and alcohol and refrigerating it to a temperature of -50 C.



   Heat the remainder of this fraction together with 0.15% carbon tetrachloride to a temperature of 510 ° C. under a pressure of 5U atm. After the whole has reached the reaction temperature add 0.4%. iron powder. Then maintain the mixture for 10 minutes at the reaction temperature. The reaction product obtained contains 14% of crystallizable cyclic compounds, mainly crude pyrene, and about 12% of constituents boiling in vacuum at a temperature. temperature above 325 C.



   Example 15: Treat at a temperature of 80 C. with three times as much propane as a boiling fraction

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 at a temperature of 325 C. from an oil obtained by the destructive hydrogenation of coal. Separate the precipitated asphalt from the oily solution. Then treat the oil, free of propane, for four to five hours in a Siemens ozone tube, at a temperature of 70 C. and under a pressure of 7 mm. of mercury, by means of dark electric discharges at 7.UUU volts and lU.UUU periods. Then dilute the reaction product with mineral spirits in the ratio of 1: 1 and filter it to remove the small amounts of insoluble polymerization products it contains.

   Distill the filtrate from gasoline by distillation and then, by vacuum distillation, subdivide it into fractions with narrow boiling zones, for example into fractions each boiling in a zone of fire 10 C. Then dilute the various fractions with a mixture of ether and alcohol and cool to a temperature of -40 C .; a high yield of solid crystallized aromatic hydrocarbons, in particular crude pyrene, is thus obtained from the fraction boiling between 320 and 400 C.



   Example 16: Rid of its solid constituents and hard and soft asphalts, by vacuum distillation, the fraction boiling above 350 C. obtained from a product obtained by the destructive hydrogenation of mineral carbon.



  Dilute the oily distillate thus obtained with 2 times its volume of methyl formate with a yield of 80%, cool it to -3 ° C. and remove by filtering the paraffin wax which has separated in proportion. by 3%. Then remove the oil from the solvent by distillation and wash it with an aqueous solution of caustic soda titrating 5 to 10%, the acid constituents being thus dissolved in proportion.

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 about 3%. Then remove the basic constituents, ie 2%, by washing with a sulfuric acid titrating 5 to 10%.



  Subject the oil thus pretreated to fractional distillation under a vacuum of 1 mm. of mercury in the presence of 1% metallic sodium. From the fractions one obtains in a yield of about 7% crystallized substances composed mainly of carbazol, anthracene, pyrene and chrysene. Pass the oil separated from the crystallized substances at a temperature of 550 C., in an atmosphere of hydrogen and under a pressure of 40 mm.,. Over a catalyst composed of nickel sulphide and molybdenum sulphide, to which case dehydrogenation occurs.

   Subdivide by distillation the oil obtained into several fractions, from which one will remove by crystallization and with a yield of 5% fluorantene, pyrene, chrysene, retene, picene and other compounds cyclical.



    Example 17: hard and soft asphalts and paraffin wax as described in Example 16 is the fraction boiling above 350 ° C. of a product obtained by the destructive hydrogenation of mineral carbon. Then remove the solvent from the oil by distillation and subject it to fractional vacuum distillation in the presence of 8% aluminum chloride. From the fractions, crystallized substances are obtained with a yield of about 7%, which mainly consist of carbazol, anthracene, pyrene and chrysene.

   Pass the oil separated from the crystallized substances, in a hydrogen atmosphere, at a temperature of 550 C. and under a pressure of 20 atm., Over a catalyst composed of nickel sulphide and molybdenum sulphide, thereby producing the dehydrogenation. Subdividing the oil thus obtained by distillation into several fractions which, by crystallization of compounds, give up.

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 cyclically laid, mainly crude pyrene, with a yield of 5%.



   Example 18.- Distill to a temperature of
380 C. under a pressure of 10 mm. of mercury the fraction of a product obtained by the destructive hydrogenation of a mineral carbon which boils above 350 C. Dilute the distillate obtained to a yield of 70% with twice its volume of methyl formate, cool it at a temperature of -3 C. and rid it of the paraffin wax which separates at a rate of 3%. Then remove the solvent from the oil by distillation and pass this oil through an atmosphere of hydrogen at a pressure of 40 mm. of mercury and at a temperature of 550 C., on a catalyst composed of nickel sulphide and molybdenum sulphide, which has the effect of producing dehydrogenation.

   Subdivide the oil thus obtained by distillation into several fractions from which the cyclic compounds, mainly crude pyrene, will be removed by crystallization, with a yield of 7 to 10%.



   Example 19: Pass at a temperature of 550 ° C., under normal pressure and in the presence of hydrogen, the fraction of a destructive hydrogenation product of a mineral carbon which boils above 300 ° C. on a catalyst composed of nickel sulphide and molybdenum sulphide. Distill the dehydrogenation product thus obtained. The fraction boiling above 400 C. constitutes a compact glassy mass.



   Heat while stirring under a reflux condenser 100 parts of this mass at a temperature of 80 C. with 12% heavy gasoline or 8% benzene and with 5% fuller's earth for half an hour, then remove with filtering the fuller's earth as well as the absorbed and partially polymerized resinous substance. A filtrate is obtained which, after removing the solvent, leaves 30 parts of a slurry.

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 crystalline. By extracting this crystalline slurry with alcohol, 15 parts of crude pyrene are obtained and, by subsequent extraction with glacial diacetic acid, 5 parts of chrysene which can be purified by crystallization either as such or by l. 'intermediary of his picrate.

   By extracting the extraction residue with an equal quantity of toluene at a temperature of 40 ° C., chrysogen is obtained. Boil the oily residue (60 parts) separated from the crystalline slurry with xylene, cool the mixture to a temperature of 20 ° C. and separate by decantation at this temperature the liquid from the undissolved part. Remove the solvent from the xylene solution, or cool the solution to a temperature of 0 ° C or below; thus obtains 3 parts of a crystallized hydrocarbon which has a green fluorescence and whose empirical formula is C36H22., its melting point being 308 C. A determination of its molecular weight gives a value close to 430.



   A similar result is obtained by treating at a temperature of 80 ° C. with 10% sulfuric acid titrating 60% the high-boiling point fraction to which 70% of a tar fraction has been added. of mineral carbon boiling between 150 and 220 C., then freeing it from acid tar, washing it with 5% of an aqueous solution at 1% of caustic soda and extracting it in the manner already described.



   Example 20: Mix the fraction boiling above 300 ° C. of a destructive hydrogenation product of a mineral coal containing 7% asphalt with three times as much of a gasoline containing 14 parts of hydrogen for 100 parts of carbon and boiling at a temperature between 40 and 150 C. Eliminate the precipitated asphalt constituents

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 and removing gasoline from the solution by distillation.



  Then heat the oil to a temperature of 320 C. along with hydrogen under a pressure of 250 atm. and passing it over a catalyst consisting of tungsten sulfide. The reaction product thus obtained is substantially free from unsaturated hydrocarbons and to a large extent free from compounds containing sulfur and oxygen.



  Then pass this product at the same time as hydrogen under a pressure of 50 atm. and at a temperature of 490 C. over a catalyst composed of cobalt sulfide and tungsten sulfide. Subdividing the reaction product obtained into fractions from which crystalline cyclic compounds such as fluoranthene, pyrene, chrysene, anthracene and picene will be removed by cooling.



   Example 81: Pass crude naphthalene at the same time as hydrogen under a pressure of 200 atm. and at a temperature of about 350 ° C. on a catalyst composed of molybdenum oxide, magnesia and zinc oxide. The thionaphthene present in the raw material is destroyed and tetrahydro-naphthalene free of naphthalene is formed.



  Boil this product for 5 hours under a reflux condenser with aluminum chloride containing its water of crystallization, whereby it is transformed into methyl hydrindene. Then pass this product at a temperature of about 500 ° C. together with hydrogen over a nickel catalyst precipitated on diatomaceous earth; methylindene is thus formed.



   Example 22: Finely grinding Ruhr coal and making a paste of it at a ratio of 1: 1 with a heavy oil obtained by destructive hydrogenation from the same coal.

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  Mix this charcoal paste with 1% finely ground tin oxalate and 0.85% carbon tetrachloride. Then pass this mixture at the same time as hydrogen under a pressure of 200 atm. through a tubular gas-heated system in which it will be brought to a temperature of 425 C.



  Before admitting the mixture into the reaction chamber, add 1% tin oxalate suspended in finely ground form in heavy oil. The feed rate is 0.23 kg. of coal paste per liter of reaction space per hour. Then pass the reaction materials through a separator heated to a temperature of 415 ° C. and in which a certain liquid level will be maintained. The gases and vapors go to an adjacent condensing vessel.



   The decay of the carbon contained in the coal amounts to 95%, the gasification is 11.5% with respect to the oil formed by the coal and by the gaseous constituents, and the asphalt content of the The heavy oil leaving the reaction chamber is 3%. The product which collects in the condensing vessel consists of 50% of constituents boiling below 325 C. These will be removed by distillation. The residue will then be refined with dilute sulfuric acid in the presence of 1% fuller's earth.



  The residue thus freed of the resin will then be subdivided in a vacuum into several fractions from which pyrene, phenanthrene, anthracene, fluorene and methyl-anthracene, dimethyl-anthracene, methyl- naphthalene, dimethyl naphthalene and methyl fluorene. One will combine the oils freed of unit compounds from the various fractions and add them to the product removed from the separator, which consists of fractions

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 high boiling oily and carbon particles. This product will be centrifuged and the oil removed in this manner will be used to pulp further quantities of charcoal.



   It is also possible to mix the residue from the product from the condensing vessel with the product which will be removed from the separator and centrifuge this mixture. The centrifuged oil will then be mixed with hydrocarbons rich in hydrogen so as to precipitate the asphalt and the minimal quantities of solid substances that it contains. As stated above, the asphalt-free oil will be separated, refined with sulfuric acid and fuller's earth, and subdivided into fractions from which said unitary cyclic compounds will be removed.



   The oil freed from said substances will be used to dissolve new coal into paste.



   Example 23: Impregnate finely ground charcoal with an amount of hydrochloric acid sufficient to neutralize the alkalinity of its ash, then with ammonium molybdate. Then mix the carbon thus previously treated, in the ratio of 1: 1, with a heavy oil obtained by destructive hydrogenation from this same carbon. Process the resulting paste with hydrogen at a temperature of 475 C. and under a pressure of 200 atm. The inorganic and carbonaceous constituents of the reaction product are separated by centrifugation and the volatile fractions are distilled off. Agitate the distillation residue with 50% mineral spirits and remove any asphalt that has flocculated.



   Then subdivide the oil freed from the asphalt into fractions and pass them through a hydrogen atmosphere at a pressure of 40 mm. of mercury and at a temperature of 550 C. on molybdenum sulphide, which results in

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 effect of producing dehydrogenation. Acenaphthene, anthracene, pyrene and chrysene can be removed from the dehydrogenation product. Introduce acenaphthene into an autoclave at the same time as 8% nickel obtained by reducing nickel nitrate. At a temperature of 270 C. and under an initial hydrogen pressure of 95 atm. tetrahydroacenaphthene is obtained.



   In the same way, hexahydro-pyrene is obtained from pyrene at a temperature of 300 C. and under an initial hydrogen pressure of 80 atm. Hexahydro-pyrene can be converted to decahydro-pyrene at a temperature of 210 ° C. and under an initial hydrogen pressure of 90 atm.



   Example 24: Treat rosin for two hours at a temperature of 380 ° C. with hydrogen under a pressure of 250 atm. in the presence of a catalyst composed of aluminum oxide and nickel oxide. Fractionate the liquid reaction product under a pressure of 50 mm. of mercury. Pass through aluminum oxide at a temperature of 450 C. and under a partial pressure of hydrogen of 20 atm. the main fraction which distils at a temperature of 260 to 300 C. The resulting product is vacuum-fractionated by operating in a column. The fraction which would boil between 380 and 400 C. under a pressure of 760 mm. of mercury gives up in crystalline form methyl-isopropyl-phenanthrene.



   Example 25: A product boiling in an area between 250 and 260 ° C. under a pressure of 50 mm. of mercury, obtained by destructive hydrogenation of carbon and which will have been distilled several times, abandoned by refrigeration 15% of a yellow crystalline deposit of pyrene and carbazol. If we leave this product, originally pale yellow in color,

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 in a closed container containing a little air it takes after 24 hours a dark brown color starting at the top, and after a few days we can only obtain 10% of a soiled crystalline deposit instead of 15% of pure yellow substance. In addition, it is difficult to remove the fatty or mucilaginous material from the mixture of pyrene and carbazol.



   If the last distillation of the product is carried out in a nitrogen atmosphere, not only is a paler and purer product obtained but the mixture of pyrene and carbazol itself is paler and purer at the start. Even by carrying out the distillation without the use of nitrogen, the product can be preserved for months without variation in color by carefully removing the air from the storage vessel, for example by introducing nitrogen, anhydride because - bonique or hydrogen; furthermore, said reduction in yield and contamination of the crystals does not occur.



     Example 86: A distillate having a boiling point between 270 and 280 ° C. under a pressure of 50 mm. of mercury, obtained from mineral coal by destructive hydrogenation, gives up 0.2% of a crystalline product of higher paraffins having a carbon number of C28 or more.



  At the same time, a sludge layer composed of 6% pyrene is obtained. By leaving this product for several days in the air, it is no longer possible to separate from the oil the paraffin which was originally in the state of finely divided crystals, because these crystals have again completely gone. At the same time, the pyrene crystalline muddy layer became discolored and shrank by 20%. However, by storing the product in an atmosphere of an inert gas, the pure paraffin crystals can be easily separated even after storage for long periods of time, and the proportion of pyrene remains unchanged. .

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   Example 27: Subdividing by single distillation an average oil having a boiling point between 220 and 3200C. obtained by the destructive hydrogenation of mineral carbon. The fraction which distills at a temperature of 120 to 1300C. under a pressure of 10 mm. of mercury gives up, by refrigeration at a temperature of -40 ° C., a crystalline product which is easily isolated when the distillate is freshly prepared. If this product is left to stay for some time under the action of air, it is no longer possible to extract the crystals from them by simple centrifuging or filtering even at a temperature of -50 C. However, if one stores the product in an atmosphere of an inert gas, the ability to crystallize at a temperature of -40 ° C. is retained for long periods of time.


    

Claims (1)

ABSTRACT ----------- A process for producing or recovering polycyclic carbon compounds containing at least four cores, comprising subjecting bituminous materials other than coal tar obtained by high temperature distillation to destructive hydrogenation and removing said carbon compounds from the resulting products, in particular their high boiling point fractions, which process may be further characterized by one or more of the following: 1.- One dilutes the high boiling fractions from the destructive hydrogenation products with a hydrocarbon rich in hydrogen, mixed with small proportions of a dilute acid and removed, preferably by crystallization, the carbon compounds of the oils thus isolated. <Desc / Clms Page number 87> 2.- One removes the asphaltic substances which they contain from the destructive hydrogenation products by means of precipitating or adsorption agents or selective dissolvents, the separated asphaltic substances are subjected to distillation and the carbon compounds are removed from the resulting distillates. 3. The destructive hydrogenation products or their fractions are subjected to dehydrogenation and the carbon compounds are removed from the resulting products. 4. - Asphaltic substances are removed from destructive hydrogenation products which contain them by means of precipitating or adsorbing agents or selective solvents, the isolated asphaltic substances are subjected to destructive hydrogenation under moderate conditions, removes asphaltic substances from the resulting hydrogenation product when it contains them and is subjected to dehydrogenation, the carbon compounds being removed from the resulting products. 5. - Dehydrogenation is carried out during destructive hydrogenation using temperatures above 480 ° C., preferably above 500 ° C. 6. - The dehydrogenation is carried out by degrees. 7. Dehydrogenation is carried out by passing the destructive hydrogenation products through the reaction zone along with finely divided catalysts. 8. - Dehydrogenation is carried out in vacuum in the presence of metals from groups 3 to 8, preferably groups 5 or 6 of the periodic system or their compounds. 9.- Dehydrogenation is carried out in the presence of fine-grained metals or their compounds and acidic substances, preferably halogens or substances capable of <Desc / Clms Page number 88> to form or to form other acids under the reaction conditions. 10. - Dehydrogenation is carried out by the action of dark electric discharges, where appropriate in the presence of solvents, under conditions of temperature and reaction time such that the formation of polymerization products is substantially avoided. 11.- The asphaltic substances and preferably also the non-neutral constituents as well as the paraffin wax are completely or partially removed from the destructive hydrogenation products or their fractions, the products thus previously treated are subjected to a distillation in the presence metals or condensing or polymerizing agents and the carbon compounds are removed from the resulting products. 12. - Dehydrogenation is carried out before, during or after the distillation. 13.- The asphaltic substances and preferably also the non-neutral constituents as well as the paraffin wax are completely or partially removed from the destructive hydrogenation products or their fractions, and allowed to act at a normal temperature or up to at 150 C. a condensing agent on the products thus previously treated, the products of this action are subjected to distillation, if necessary in the presence of metals or condensing or polymerizing agents, and the carbon compounds are removed. of the resulting products. 14. - Paraffin wax and all or part of the asphaltic substances are removed from the destructive hydrogenation products or their fractions, and the products thus previously treated and the liquid are subjected to dehydrogenation if necessary. carbonaceous compounds are removed from products <Desc / Clms Page number 89> resulting. 15.- The pitch-forming constituents are removed from the destructive hydrogenation products or their fractions or dehydrogenation products, for example by treating them with adsorbents or condensing agents. , then the carbon compounds are removed from the resulting products. 16. - Asphalt, preferably only hard asphalt, is removed from the destructive hydrogenation products which contain it, the resulting oil is subjected to destructive hydrogenation under predominantly hydrogenic conditions, and subjected to The hydrogenation products require dehydrogenation and the carbon compounds are removed from the products obtained. 17. The liquid products which remain after the carbonaceous compounds have been removed therefrom are subjected to dehydrogenation and further quantities of carbonaceous compounds are removed from the resulting products. 18. - Destructive hydrogenation products containing cyclic carbon compounds of the aromatic series, or fractions thereof, are subjected to heating in the presence of catalysts producing isomerization, the resulting products are dehydrogenated and removes carbon compounds from the products obtained. 19. - In order to produce cyclic carbon compounds containing side chains, coal pulps are subjected to destructive hydrogenation under pressure and at temperatures below 440 ° C. with a feed rate such that gasification s' increases to less than 13% with respect to the oil and gas formed by coal, and preferably with a proportion of catalyst such as heavy oil which <Desc / Clms Page number 90> left the reaction vessel contains less than 5% asphalt. 20.- In order to produce hydrogenated cyclic carbon compounds, the destructive hydrogenation products or their fractions are subjected to dehydrogenation, the carbon compounds are removed from the products obtained and the unit compounds obtained are subjected to catalytic hydrogenation. . 21. The processes defined in paragraphs 1 to 18 and 20 are applied to the production of polycyclic compounds from products of destructive hydrogenation of coal tar obtained by distillation at high temperature. 22. - The processes defined in paragraphs 1 to 21 are applied to the production of polycyclic compounds containing less than four rings and containing side chains. 23. The processes defined in paragraphs 1, 2, 4 to 10 and 12 to 21 are applied to the production of polycyclic compounds containing less than four rings and free of side chains. 24. - The processes defined in paragraphs 1 to 18 and 20 are applied to the production of polycyclic compounds from recent or fossil resins or balms or from products containing them. 25. - The liquid products from which the polycyclic compounds will be removed are kept away from oxygen or air or other gases containing elemental oxygen. 26. - As new industrial products, polycyclic carbon compounds obtained by the processes defined above.