FR2503704A1 - PROCESS FOR THE PREPARATION OF AROMATIC NITROGENOUS HYDROCARBONS FROM MIXTURES OF AROMATIC HYDROCARBONS - Google Patents

Abstract

THE INVENTION CONCERNS THE PREPARATION OF NITROGENOUS HETEROCYCLES FROM MIXTURES OF AROMATIC HYDROCARBONS, IN PARTICULAR FROM COAL TAR FRACTIONS, USING A POROUS MINERAL SUPPORT, AND SELECTIVE ELUENTS. THE MIXTURE OF AROMATIC HYDROCARBONS IS MIXED IN THE RATIO 3: 1 TO 2: 5 WITH THE CARRIER, AND SUCCESSIVELY SEPARATED WITH A NON-POLAR HYDROCARBON AND AN AROMATIC HYDROCARBON IN A FRACTION ALMOST NITROGEN-FREE AND IN A FRACTION RICH IN NITROGEN. THE ELUANTS ARE RETURNED INTO THE CYCLE AND THE SUPPORT MATERIAL IS THERMALLY REGENERATED. THE NITROGEN RICH FRACTION MAY BE USED EITHER DIRECTLY OR AFTER A SIMPLE REFINING PROCESS FOR ITS FUTURE TREATMENT.

Description

Process for the preparation of nitrogenous aromatic hydrocarbons from

mixtures

aromatic hydrocarbons.

  The present invention relates to a novel

  process for the preparation of azo aromatic hydrocarbons

  from aromatic hydrocarbon mixtures.

  The most important starting materials for the preparation of atomic hydrocarbon mixtures

  Technical ticks are tar oils. The melanges

  liquid hydrocarbons from this source

  contain, in addition to carbon and oxygen,

  considerable amounts of heterocycles, such as for example compounds of oxygen, sulfur and nitrogen. These heterocycles are prepared in the form of heterocompounds

for the chemical industry.

  As an example of the objective "preparation of

  pure nitrogen compounds ", there will be mentioned the separation of hetero-

  cycles from tar, such as quinoline,

  I indole or carbazole from coal tar.

  To prepare these compounds, from

  hydrocarbons from coal, extractive processes or

  refining by distillation (see, for example, H.-G.

  Franck, G. Collin, Steinkohlenteer, Publisher Springer,

Berlin 1968).

  The disadvantage of the above process is

  in that when preparing mixtures of hydro-

  technically pure carbides, with heteroatoms, process combinations with many stages

are necessary.

  The object of the invention is to develop a process allowing the preparation, from fractions of aromatic hydrocarbons, comoose nitrogen in a state of purity such that they can be sent directly, or for example after a single

  recrystallization, to a technical treatment operation

later.

  This object is achieved according to the invention by homogenizing nitrogen-containing aromatic substance fractions 1 with a mineral content material 2 in the ratio 3: 1 to 2: 5 in a mixer 3, filling a separation column 4 and separating them with at least two different eluting agents 5 and 6, under

  pressures of 1 to 30x105 Pa and at temperatures below

  above the boiling point of each of the eluents, in a nitrogen-poor fraction 7 and a nitrogen-rich fraction 8, recovering the eluents 5 and 6 by distillation 9, returning them to the process, and

  reusing support material 2 at least partial-

  after thermal regeneration 10.

  Without privileging a particular theory,

  may be allowed to form at the time of deposit of substances

  these hydrocarbons on the support material, product having a high surface activity, a particularly strong association between the carrier material and the nitrogen compounds, which makes possible separation and differentiated washing of hydrocarbons

of the support.

  The stationary phases usually used

  column chromatography, based on silica gel, aluminum oxide or their mixtures, have been shown to be

appropriate support.

  As might be expected, there are various effects that are influenced by the volume of

  pores, granulometry and activity levels. The UTI

  the use of an aluminum oxide, active as acid and silica gel with a particle size of 0.063 to 0.200 mm

  has proved particularly advantageous.

  As the eluent, it is possible to envisage, according to the invention, for the separation of the nitrogen-depleted fractions, non-polar hydrocarbons, in particular aliphatic hydrocarbons such as alkanes in the form of

  C5 to C10 or cycloalkanes. To prepare the frac-

  nitrogen-enriched compounds, aromatic compounds such as benzene, toluene, pyridine, quinoline, and compounds are used according to the invention.

  analogs or mixtures thereof.

  The execution of the process according to the invention is described on the basis of the block diagram represented

  in the accompanying drawing. The fraction of aromatic hydrocarbons

  Nitrogenous material 1 is diluted with a small amount of a highly volatile auxiliary solvent 11, such as chloroform, and is poured onto the carrier material in the mixer 3. After homogenization,

  the auxiliary solvent 11 is evaporated under vacuum, and

  see in the cycle through a condensation 12.

  It is also possible to deposit directly

  the aromatic hydrocarbon fraction 1, without auxiliary solvent 11, if necessary through a

  heat exchanger 15, on the support material 2.

  In this case, to avoid evaporation, the start of boiling of the fraction must not be exceeded.

aromatic hydrocarbons 1.

  The homogeneous fluent mixture is poured into the separation column 4. If the aromatic hydrocarbon fraction 1 contains constituents with difficulty

  eligibility, it is appropriate to use a column of

  4-part partion, which is filled up to% of its volume with an unloaded carrier material 2 as a separation zone. The pouring and separating zones are separated from each other by a filtering layer of coarser material, for example

  of quartz sand. Unlike the subject matter of

  port of the pouring zone, it is not necessary that the separation zone be regenerated after each cycle.

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  The separation column 4 is then filled

  non-polar eluent 5, which preferentially extracts

  the non-nitrogen fraction 7 of the hydrogen fraction

  aromatic carbides 1. Eluent 5 is separated from fraction 7 by vacuum distillation 9, preferably

  continued, and returned to the cycle.

  Then you prepare in the same way the

  Nitrogen fraction 8 with aromatic eluent 6.

  When the aromatic hydrocarbon fraction

  1 contains constituents 13 which are difficult to

  these can be extracted in the

  milking with an additional solvent 14, and prepared

  as it has been described as a third fraction.

  The eluent or solvent remaining in the column

  separation is evaporated under vacuum and treated after

  condensation 12 for reuse.

  The support material that becomes unusable is sent to the regeneration 10, where it is regenerated

  at temperatures of 400 to 7000C in an oxidizing atmosphere.

  An analytical procedure was introduced under the

  extrographic name for mineral oil residues.

  (J. Hallasz, Erdol u Kohle, 1979, 32, 571), the

  the test was not adapted to a technical implementation but was oriented in a purely

  analytic, and thus being particularly expensive.

  Other chromatography methods oriented towards analysis, such as thin layer chromatography,

  which are appropriate purely and simply to the separation

  very small quantities of substances, can not be

  not be transposed on an industrial scale.

  We found, however, in a surprising way

  only in a simplified separation process,

  cutable on an industrial scale in a single stage, starting from relatively low concentrations, it was

  possible to achieve concentration and impoverishment

  selective nitrogenous hydrocarbons, on a

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  the preparation, even from products derived from coal. In addition, the process described above can be modified in that deliberate removal of only the precise fraction of the nitrogen-rich or nitrogen-deficient fraction is desired while the remaining material is removed in an accelerated manner. without a decrease

  the precision of the separation in the field of interest

  health. An advantage of the process consists in the strong

  enrichment of compounds which are contained in the

  departure at a relatively low concentration,

in one operating stage.

  Another advantage is the overall high efficiency

  nitrogenous heterocycles, which allows a;

  of substances present in the starting material. A particular advantage of the process is the possibility of using the mineral support materials several times. The regeneration of the support used, stained with small amounts of substances, is carried out by

  combustion in a current of air at 400-7000C. The materials

  The regenerated carrier resins, even after 7 regeneration cycles, with respect to the fresh material, a loading capacity of 85% and a separation accuracy of 75% (ratio of the purities obtained in

the same conditions).

  Non-limiting examples 1 to 4 are given

  as an illustration of the invention.

EXAMPLE 1

  A methylnaphthalene oil obtained by

  distillation from the treatment of coal tar

  the, having an indole content of 2.5%, is

  after dissolution in 1.3 times its weight of chlorinated

  1.8 times its weight of 0.063-

  0.2 mm (Merck), relative to the amount of oil involved. The chloroform is then evaporated under a pressure of 4000 Pa. Elution with 22 times its weight of n-hexane, is obtained at room temperature. at room temperature and under a pressure of 3.754105 Pa, an indole-free fraction, with a yield of 96.4%, relative to the oil involved. The subsequent elution with 10 times the amount of toluene gives a 83.4% indole fraction, with a yield of 2.7% (relative to the

amount involved).

  It remains a residue of 0.9% on the material of

  support. The eluent is separated completely by distillation.

  continuously in a 4000 Pa session and returned to the cycle. The indole thus obtained may, if necessary for further processing, be brought by simple distillation to high degrees of purity. The contaminated silica gel is first vacuum-stripped of the solvent residues and then sent to a cylindrical vessel heated from above at temperatures of 4500 ° C, where the organic phase is burned against the flow

  with introduction of air. After cooling, the

  of supDort can again be coated with blends

  aromatic hydrocarbons and used in the separation

  tion. The loss of carrying capacity per regeneration cycle

is less than 4%.

EXAMPLE 2

  A methylnaphthalene oil obtained by distillation from the coal tar treatment, having an indole content of 2.5 a, is heated to 140-150 ° C and deposited, by mixing, with 1.8 times its weight of silica gel , with a particle size of 0.063-0.2 mm (Merck), relative to the amount of oil involved. Reduced with 22 times the weight of n-hexane at room temperature and under a pressure of 3.5y105 Pa, a fraction free of indole with a yield of 96.0% relative to the oil involved. The subsequent elution with 10 times its weight of toluene gives an indole fraction to

83.1% with a yield of 2.7%.

  There remains a residue of 1.3% on the material of

  support, which is regenerated as in example 1. The

  Ants are recovered as in Example 1 and returned to

the cycle.

EXAMPLE 3

  The anthracene oil formed during the primary distillation of coal tar with a carbazole content of 2.4% is treated with the same

  way, on aluminum oxide, neutral active (Riedel-de

  Haen) and introduced into the elution column, as described in Example 1. Elution with 25 times its weight of n-hexane at room temperature and at a pressure of 5.305 Pa gives a fraction free from carbazole with a yield of 84.0%, relative to

  the anthracene oil involved. The subsequent treatment

  with 12 times its weight of toluene gives a fraction

  carbazole at 26.7%, with a yield of 8.1.

  Then, with 15 times the weight of pyridine, 9% additional substance. There is a residual of 2.0% on the carrier material. The fractions are freed, by vacuum distillation under 4000 Pa.

  solvent, which is returned in the cycle.

  To obtain additional enrichment

  carbazole, the carbazole fraction obtained is

  naked in 6.5 times its weight of chlorobenzene at 90-1000C.

  The solution is cooled to 0 ° C., the crystalline material which forms is filtered off and dried. 89% of carbazole is thus obtained with a yield of 5% relative to the carbazole content of the oil.

of anthracene put into play.

  The main product is thus free from

  bazole, an annoying product that distils at the same time as

  him, and it can be used for the preparation of the

  thracène. The carbazole thus prepared serves as a starting material for the preparation of dyes, insecticides

  and special plastics.

  The stained aluminum oxide is first

  The solvent remains under vacuum and then sent upwards into a cylindrical container, heated from the outside, at a temperature of 700 ° C., and there, the organic phase is burned against the current with the introduction of air. After cooling, the support material may be coated again with aromatic hydrocarbon mixtures and used in the separation. The loss of

  carrying capacity is around 3%.

EXAMPLE 4

  When preparing anthracene for

  coal tars, a product is formed which

  contains about 31% anthracene and 25% carbazole.

  This mixture of substances is dissolved in the chloroform used as an auxiliary solvent at approximately 450 ° C. and with a ratio of 1: 0.9, and is deposited on 0.75 times its volume.

  weight of aluminum oxide, active acid (Riedel-de-Haën).

  The quantitative auxiliary solvent is then removed.

  by vacuum distillation. The support material thus coated is poured into the pouring zone of the separation column, the lower half of which serves as a separation zone and is filled with aluminum oxide.

neutral active.

  When eluting with 25 times its weight of

  n-hexane, in relation to the substance used, it appears

  a nitrogen-free fraction with a yield of 64.5%. The subsequent treatment with 12 times its weight - toluene provides with a yield of 22.8% (relative to the substance involved) a fraction of

carbazole at 82.6%.

  By elution with 10 times its weight of pyridine

  no, another fraction is obtained with a yield of 8.0%. It remains on the support material 4.7% of substance. The fractions are freed of the solvent

  by vacuum distillation, as already described.

  Regeneration of the support material of the pouring zone is carried out as in Example 3. The support material of the separation zone is regenerated only after cycles.

Claims (7)

  1. Process for the preparation of aromatic hydrocarbons   nitrogenous materials from hydrocarbon mixtures   aromatic compounds, characterized in that the mixtures of   aromatic carbides (1) are homogenized with a mineral carrier material (2) in the ratio   3: 1 to 2: 5 in a mixer (3), in that they are   in a separation column (4) and separated with at least two different liquid eluting agents (5, 6),   under pressures of 1 to 30x105 Pa, and at temperatures of   below the boiling point of the eluting agent (5, 6) to a nitrogen-poor fraction (7) and   in a nitrogen-rich fraction (8), in that the   (5, 6) are recovered by distillation (9) and   in the cycle, and in that the support material   (2) is reused at least partially after regeneration thermal ration (10).   2. The process of claim 1, wherein   characterized in that to improve the mixing, the aromatic hydrocarbon mixtures (1) are heated prior to   to be poured onto the support material (2) in the medium   langeur (3), at temperatures lower than their   boiling point, or diluted with a very volatile auxiliary solvent (11), which is evaporated under vacuum after   mixed, liquefied and returned to reuse.   3. Process according to any one of the   1 and 2, characterized in that one uses   porous carrier material, mineral (2) of the oxy-   of aluminum, active acid, or silica gel of a particle size of 0.063 to 0.2 mm.   4. Process according to any one of   Claims 1 to 3, characterized in that the separation column (4) is subdivided into 2 zones, a pouring zone and a separation zone, and that the   separation zone, which is filled with   pure port, represents at most 80% of the volume of the column.   5. Process according to any one of the   Claims 1 to 4, characterized in that non-polar hydrocarbons (5) are used as the eluent for the low nitrogen fraction (7), and for the minor fraction   in nitrogen (8), aromatic compounds (6).   6. Process according to any one of the   1 to 5, characterized in that the soiled carrier material (2) is regenerated after washing with a   other solvent and vacuum drying at 400-700WC in atmospheric oxidizing phenomenon.   7. Process according to any one of   Claims 1 to 6, characterized in that   as a mixture of aromatic hydrocarbons (1),   from the treatment of coal tar.