DE699307C - Obtaining polynuclear cyclic compounds - Google Patents

Description

Obtaining polynuclear cyclic compounds It is known polynuclear to win cyclisehe compounds by extracting coal and others solid: carbon-containing substances first subjected to its pressure hydrogenation and separates the cyclic compounds from the products obtained.

It has been found that such compounds are easier to obtain can, if the extracts or their fractions undergo heat splitting without causing subject to substantial hydrogenation and the substances thus obtained become moder whose fractions separates the three or more compounds to be obtained.

To carry out the process, the solid carbonaceous Substances such as coal, peat or hard pitch, crushed and mixed with a solvent. Suitable solvents are e.g. B. middle oils or smoldering oils or fractions of these, insbesündere the substance to be extracted, e.g. B. the coal, related, z. B. off Oils obtained from coal, also phenols or fractions containing phenod, in whole or in part hydrogenated naphthalene, anthracene, phenanthrene or other polynuclear compounds or mixtures of several solvents; vori which z. B. one a hydrogen-releasing, can be. The extraction is carried out at temperatures from zoo to 500 °, advantageously 300 to 450 °, and usually under increased pressure, preferably above aoat, z. B. from ioo to iooo at, z. B. by the vapors of the solvent or else can be generated by gases. The temperature or the pressure. Or both can can be increased continuously or gradually. The extraction can also be carried out in the presence small amounts of hydrogen and -b-zw. or catalysts, e.g. B. the connections of the metals of the 4th to B groups.

The heat splitting of the extracts obtained is usually at temperatures from 45o to 500 ° or more, e.g. B. at 55o to 750 °, and optionally under increased Pressure, z. B. at 2o to 30o at or more, carried out, optionally in the presence of gases or vapors such as water vapor, hydrogen, nitrogen or oxides of carbon; however, hydrogen or hydrogen donating gases should be used under conditions in which no significant hydrogenation occurs; at ordinary pressure hydrogen can generally be used without restriction; when working under Pressure, a partial hydrogen pressure of less than i o a1 is maintained; only at Temperatures above about 55o 'can be up to about 20 to soat. The extracts can also be used together with a mineral oil or tar oil to be cleaved, e.g. Tie known splitting devices are treated.

If the extraction is carried out without catalytically active additives it is advisable to carry out the cleavage in the presence of catalysts, e.g. B. Metals the q .. to B. group or their compounds, in particular their oxides, halides, Phosphates or sulfides, or silicon-containing substances, e.g. B. Fuller's earth, or active charcoal, which is advantageous with acids, e.g. B. hydrogen fluoride, or pretreated gases are,. or halogen, hydrogen halide, metal halides or phosphorus compounds, or mixtures of said catalytically active agents. But it is It is also advantageous to add catalysts when the extracts are already in the presence catalytically active substances were produced and still contain them.

It has also proven to be useful to clean the extracts before cleavage to be broken down into fractions, e.g. B. by treatment with solvents such as gasoline or benzene hydrocarbons; liquid sulfur dioxide, phenols; liquid ammonia, Aniline, nitrobenzene, furfurol, phenylhydrazine, glycol derivatives, fumaric acid, keto acid codex also liquefied hydrocarbons, which are gaseous at normal temperature, such as propane, athan or butane and their mixtures, or mixtures of both types of Solvents. The separation into fractions can sometimes also be done by distillation, especially under reduced pressure.

Before the cleavage, the extracts or their fractions can be one Subject to dehydration, e.g. B. at q.öo to 700 °, in particular 400 to 600 °, appropriate in the presence of catalysts. The known metals are used as catalysts and metal compounds. You can also use gases and vapors, e.g. B. water vapor, Hydrogen, nitrogen; @Add carbon oxide, carbonic acid or methane. The dwell time is chosen so that only a slight dehydration occurs and only in the subsequent one Heat treatment, e.g. B. is carried out for a longer stay, the actual Split occurs. The dehydration and cleavage are expediently carried out in one operation. off, the apparatus being designed in such a way that in the first part I only have one Hydrogen splitting and only in the further part the splitting is effected.

The dehydration can also take place in other ways, for example by passing over over copper at 350 ° with the addition of a limited amount of air or oxygen or z. B. be done by heating with sulfur to 150 to 300 °. It can too other hydrogen-binding agents such as selenium, tellurium, nitrogen oxides or diluted ones Nitric acid. The dehydration can also be caused by treatment with Halogen directly or through halogenation and elimination of hydrogen halide, optionally with the addition of catalysts. These ways of working have the advantage that at relatively low temperatures and with short Residence time in the reaction chamber can be worked.

The products obtained from heat splitting contain the three and, polynuclear compounds in easily crystallizable form; they can for example according to the methods customary in tar processing, e.g. B. by fractional Crystallization, which may have taken place beforehand or in between Redistillation is facilitated, or by using solvents or by chemical metito-denes that are based on specific reactions of each to be obtained Body based, e.g. B. Potash or sulfonation can be obtained.

If the cleavage products contain low-boiling fractions, one can .from it in some cases also low-boiling cyclic compounds, e.g. B. phenols, toluene and xylene, win.

If the extracts are subjected to dehydration before cleavage, polynuclear cyclic compounds can be found in some cases Remove the dehydration products in the manner described above and then only the dehydrogenation product completely or partially freed from cyclic compounds columns.

You can also do the dehydration or the cleavage or both several times carry out. and after one or more stages, or after each stage, those to be won Separate connections.

Before separating the uniform body, it is advisable to remove the dehydration respectively. Cleavage products of P: polymerization products and those for polymerization to free substances that tend to be, e.g. B. by treatment with a solvent, e.g. With hot alcohol or one consisting of alcohol and benzene, tolu-ol or xylene Mixture or boiling, such as acetone, or halogenated hydrocarbons, such as chloroform ! or ethylene chloride, in the presence of adsorbents such as fuller's earth, fuller's earth or active coal. Refining can also be done with acids such as sulfuric acid or Chlorosulphonic acid, or salts with a coddening effect, such as iron chloride, aluminum chloride or zinc chloride.

Before the thermal cleavage of the extracts, the paraffin-like fractions removed therefrom, e.g. B. by treatment with solvents and cooling or, in the case of lignite extracts, also in a purely mechanical manner, such as by standing, centrifuging, filtering or cooling.

Depending on the selected starting materials, a wide variety of polynuclear compounds such as pyrene, chrysene or fluorene can be obtained. - Example i `An extract obtained from hard coal is smoldered by heating in a retort to 600 ° under atmospheric pressure. The vapors formed are then passed at 600 ° with a residence time of 3 seconds over a dehydrogenation catalyst consisting of active charcoal on which 70/0 molybdenum sulfide and 30/0 cobalt sulfide are deposited. The product obtained is fractionally distilled. The fractions up to 180 ° consist largely of benzene, toluene and higher homologues. A number of solid aromatic compounds, namely aene naphthene, fluorene, anthracene, pyrene, methyl and dimethyl pyrene and chrysene, are obtained from the higher-boiling fractions by crystallization in a yield of 12%.

Example 2 hard coal is with middle oil under one. Printing from i5o at q.20 ° in Cegenwvaxt extracted from hydrogen. The extract obtained is after filtering off the ash together with the middle oil at i 5 at pressure and a temperature of 70 ° split so that coke is formed as a residue. The "fission product is fractionated. -The gasoline obtained consists largely of aromatic hydrocarbons; the middle oil is used to grind and extract new coal. The higher boiling ones Factions will be. with 2o% Sch ", efelblumen 2 hours heated to 300 ° and on dehydrated this way. From the dehydration products at 5omm Hg from 23o to 38o 'boiling fractions are obtained by crystallization in a yield of 15% of the aromatic compounds mentioned in Example i, in particular pyrene.

Will the. The extract is subjected to pressure hydrogenation and the product dehydrated and worked up in the same way, the yield is an .aromatic compounds only about 65% of the amount given above.

Claims (1)

PATENT ANSL'RUC1-1: The use of high-boiling cleavage products from coal extracts as starting materials for the production of trinuclear or polynuclear cyclic compounds. .