JPH02199192A - Separation and purification of anthracene derived from coal tar - Google Patents

Abstract

PURPOSE: To separate and purify anthracene by cooling anthracene oil to a specified temperature or lower in a vertical crystallization vessel, separating the residual oil by gravity, treating the formed unpurified anthracene crystals with a specified solvent in the same vessel and subjecting the crystals to filtration or the like.

CONSTITUTION: Anthracene oil in the thinnest possible form is fed into a vertical crystallization vessel having a highly developed heat-exchanging surface and cooled to 80°C or below. The residual oil is separated by gravity, and the formed unpurified anthracene crystals are treated with an aprotic or dipolar solvent in the same vessel. The purified anthracene crystals are separated from the suspension in the solvent by filtration, centrifugation or other known methods, and the solvent is recovered and returned to the process. Thus, the coal-tar- derived anthracene can be separated and purified.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for the separation and purification of anthracene from coal tar feedstock.

Chemical transformation of anthracene or its most important impurity
The method for the separation and purification of anthracene from coal tar fractions was abandoned long ago and is now used in industrial practice by J. Polaczek et al. 'Przemy.
sl Chemiczny' 60.168-170
(1981), distillation and crystallization methods are used.

In the chemical industry, the crystallization method of anthracene separation is of primary interest due to its lower energy consumption compared to the distillation method. The process described below presents additional operational difficulties due to the high precipitation points of anthracene and its associated carbazole and phenanthrene.

A typical industrial process involves crystallizing anthracene oil by cooling to a temperature within the range of 60-70°C, followed by centrifugation or filtration of the crude anthracene crystals;
Single or repeated recrystallizations are carried out from solvents such as lysine base, acetone or toluene, and the final step is separation of the purified anthracene from the mother liquor by centrifugation or filtration. Jin's method has many drawbacks related to the multicomponent character of anthracene oil and crude anthracene;
This makes the crystallization process less selective and difficult to separate the crystals from the oil spill. Crystallization of crude anthracene from anthracene oil in a rotating crystallizer produces crystals with large amounts of oil contaminants absorbed onto the surface of these crystals. Therefore, the relative efficiency of crude anthracene separation from 7-anthracene oil is low and the loss of anthracene into the residual oil is very high. Recrystallization of crude anthracene from typical solvents causes significant energy consumption and loss of solvent used.

Improvements in the crystallization method of Anthracef separation and purification as shown in the patent literature have contributed to some economical improvements to this process, but this has not led to any substantial improvements to Boland Patent No. 131.628 and 131.6
No. 64 discloses a method involving the application of an anthracene oil diluent and a two-step embodiment of the method, but increases the quality and yield of crude anthracene without the need for extra equipment (mixers and centrifuges). was obtained at the cost of no essential modification in the conditions of crystal nucleation and growth, and no clear increase in the distribution coefficient of anthracene between the crystalline phase and the mother liquor.

Moreover, as before, it was necessary to completely separate the anthracene in the form of a solid semi-finished product, the handling of which is particularly difficult, because some unavoidable content of oily substances is formed in it. This is because it inhibits the brittleness of objects, and this is due to the following N
Air conveyance and accurate dosing are essential for the supply of air in the II manufacturing process.

First Borland patent for method of anthracene purification
As described in No. 37,241, application of new selective solvents significantly improves their efficiency, but application separate from the methods of crude anthracene separation is important for the implementation of these methods. It is necessary to construct a new separate facility.

The process according to the invention is superior to the process for the separation and purification of coal tar-derived anthracene by combining these two operationally in one common facility.

In the process according to the invention, anthracene oil is introduced into a vertical crystallizer with a highly developed nine-thermal redirecting surface, preferably a tubular crystallizer with a flow of cooling medium in the internal tubular space, and then It is then completely cooled in the crystallizer to a temperature below 80°C, preferably within the range of 0-70°C, and
Keep at this temperature for ~20 hours, then drain this mother liquor preferably by gravity and pour into the same crystallizer, preferably with 40-25 wt. of a neutral, dipolar solvent and at a temperature in the range of 20-60 °C This formed then crude anthracene crystals are treated with and finally the purified anthracene is separated as a solid phase suspended in a solvent by filtration, centrifugation or any other known method, washed and dried, The solvent is regenerated and recycled to the process.

If the initial anthracene oil contains solid contaminants, especially coal tar-derived quinoline soluble alpha-2 components, it is preferably separated using a filter aid such as coke breeze or separated by a slit filter with external removal of the cake. It is desirable to carry out preliminary filtration using.

′! Especially when the anthracene content of the initial anthracene oil is low (below 511), the new portion of anthracene in the crystallizer is cooled several times until the volume of unrefined anthracene crystals fills at least quarter of the crystallizer capacity. Repetition is desirable because it allows better utilization of the manufacturing capacity of the device.

It is desirable to dilute the initial anthracene oil with a suitable diluent, which allows the crude anthracene crystallization process to be carried out at low temperatures without worrying about complete freezing of the crystallizer contents.

As diluents, linear and branched aliphatic and cycloaliphatic Cs
+exa-hydrocarbons, as well as hydrocarbons of the general formula I (wherein n is an integer within the range from 1 to 5), as well as two or more substituted isopropyl derivatives of naphthalene, may be used as anthra-7 It is used in an amount of 20 to 100 parts by weight based on the oil. Cooked with ethylene or propylene/
It is particularly desirable to use technical products such as di- and polyalkylbenzene fractions from the process of zene alkylation, aliphatic volatile oils and pyrolysis oils, or propylene oligomers. Because of the low cost of these diluents,
It is unnecessary to recover and regenerate these, which remain in the discharged anthracene oil, which is used as coal carbonium or as raw material for the production of carbon black.

As the neutral or dipolar solvent used to treat the unpurified anthracene crystals submerged in the crystallizer wall soil, preference is given to organic amides, sulfoxides or nitriles, especially organic amides, sulfoxides or nitriles, especially those of the general formula is a C3-alkyl group, R2 is a hydrogen atom, a methyl group or an ethyl group, R3 is a C1-C3-alkyl group, and R2 and Rst
Both m are C3-C,-fulkylene groups, whereas R1 and R3 are both C,-c2alkylene groups, oxyalkylene groups, or azoalkylene groups. These neutral, dipolar solvents include N-methylgyrolidone, N-methyl-caprolactam, N,N-dimethylacetamide, N-methylformamide, N-formylmorpholine, water and mixtures thereof, as well as dimethyl sulfoxide and acetonitrile. and solvents such as β-hydroxypropionitrile.

The suspension of crystals formed after treatment of crude anthracene with a neutral, dipolar solvent is transferred to a separation device under full gravity, by air or using a suitable pump, and after separation of the extract obtained nx The neutral, dipolar solvent used in this method for the crystallization of purified anthracene is then treated singly or repeatedly with low-boiling polar solvents, especially methanol, ethanol, water or mixtures thereof, as well as acetone and mixtures of water with methyl ethyl ketone. A washing operation is carried out, and in the final operation the crystals are all dried in a known manner and treated to anthraquinone or packed in bags. The separated extract is further processed in this manner to recover the neutral, dipolar solvent and to separate as much of the carbazole as possible. Regeneration of the solvent is preferably carried out by vacuum distillation, preferably in a 1:1 ratio,
Hydrocarbons are removed by periodic dilution and precipitated solids are separated by filtration, centrifugation or any other known method.

Anthracene is separated and refined according to the invention in a tubular crystallizer, preferably comprising a bundle of metal tubes with an internal diameter of 5 to 20 mm. ! ! 7 rows and cooled with water or 1 water flowing into the internal tubular space.

The process according to the invention yields the possibility of producing purified anthracene on a purity 95 gt plate from anthracene oil containing anthracene at 3 wt est, with an overall efficiency of 75-80 g/n anthracene contained in the feedstock. reach excellent.

The examples below illustrate the method according to the invention, but this is not intended to limit the scope of its application.

Example 1 A sample of anthracene oil 214Ii' having the composition and properties shown in the first coating is placed in a vertical tubular crystallizer equipped with a heating jacket. The anthracene oil is heated with circulating hot water in the heating jacket of the crystallizer to obtain a homogeneous liquid phase (its temperature is above 90° C.).

Slow cooling of the oil is then initiated by lowering the temperature of the water circulating in the jacket at an average rate of 0.1°C/min. This process is continued until a final crystallization temperature of the oil of 50°C is obtained. The contents of the crystallizer are kept at 50 DEG C. for 1 hour and then separated off at the mother liquor tl force in an amount of 128 g. An amount of 86 g of unpurified anthracene crystals remains in the crystallizer, washed on the wall. These are treated with 120 g of N-methylpyrrolidone in the same crystallizer at room temperature. After 6 hours, the contents of the crystallizer in the form of a suspension are filtered through a Puchner funnel and purified to give 199 g of a filtrate containing the crossanthracene case Φ as well as N-methylgyloride.

Wash this cake in two sections of 12 Qd each. 7 g of anthracene are obtained with a purity of 96.8 (yield of 52.81 based on the theoretical yield calculated on anthracene). The filtrate is completely distilled and N-methylpyrrolidone 119I is recovered and recycled.

Composition of the anthracene oil used in the experiments described in Table 1 Examples 1-5 The following content was determined by weight by UV/VIS method: anthracene 6.0 phenanthrene 64.6 carbazole 1.5 Example 2 Table 1 Sample 214,9' of anthracene oil having the composition and properties shown in (e) placed in a crystallizer as in Example 1.

The anthracene oil is heated with circulating hot water in the heating jacket of the crystallizer to obtain a homogeneous liquid phase (its temperature being above 1190° C.). As in Example 1, the oil is cooled until a final crystallization temperature of 50° C. is obtained. The contents of the crystallizer are 1
It is kept at 50° C. for an hour and then separated by gravity over the mother liquor in an amount of 165 IIO. In the crystallizer, 78g was deposited on the wall.
An amount of unpurified anthracene crystals remains. 12g of water (10
Weight 1) Treat this with 120 I of N-methylpyrrolidone in the same crystallizer at room temperature. After 6 hours, the contents of the crystallizer in the form of a suspension are filtered through a Puchner funnel and a cake of purified anthracene as well as N-methylgyrolidone-containing a[199,! i' is obtained. The cake is washed with two portions of 120-liter pure methanol. Purity 9
Anthracene 11fI having 7.91 t-(yield of 85.9 t based on the theoretical yield, calculated by anthracene fraction) is obtained.

The filtrate is dried under vacuum to recover N-methylpyrrolidone 119I.

Example 3 216 gff 1 sample of anthracene oil having the composition and properties shown in Table 1 is placed in a crystallizer as in Example 1.

Anthracene oil is heated with hot water circulating in the heating jacket of the crystallizer to obtain homogeneous liquid phase gold (its temperature is above 90° C.). It is then cooled in oil as in Example 1, but at an average rate of 0.2° C./min until a final crystallization temperature of 60° C. is obtained. The contents of the crystallizer are kept at 60° C. for 1 hour and the mother liquor (residual oil) is then separated by gravity in an amount of 116 g. In the crystallizer, unpurified anthracene crystals remain in an amount of 100 g, deposited on the walls. These were treated at room temperature in the same crystallizer with 120 g of N-methyl birolide. After 6 hours, the contents of the crystallizer in the form of a suspension are filtered through a Puchner funnel and 214 g of a cake of purified anthracene and a filtrate containing N-methylpyrrolidone are obtained. 120 each
Wash the cake with two portions of pure methanol. Anthracene 611 with a purity of 95.596 t- (44.2% yield based on the theoretical yield, calculated on anthracene) is obtained. The filtrate is subjected to total vacuum distillation to recover 119 g of N-methylpyrrolidone.

EXAMPLE 4 A 220 gt sample of Antosene oil having the composition and properties shown in Table 1 is placed in a crystallizer as in Example 1. The anthracene oil is heated with hot water circulating in the heating jacket of the crystallizer to obtain a homogeneous liquid phase (its temperature is above 90° C.). The oil is then cooled as in Example 1 until reaching the final crystallization temperature of 40°C. The contents of the crystallizer are kept at 40° C. for 1 hour, after which the mother liquor is separated by gravity in an amount of 146 g. Unpurified anthracene crystals remain in the crystallizer, deposited on the walls, in an amount of 77 g. These are treated with N-methylpyrrolidone 120II in the same crystallizer at room temperature. After 6 hours, the contents of the crystallizer in the form of a suspension are filtered through a Puchner funnel and a cake of purified anthracene as well as N-
A filtrate 189I containing methylpyrrolidone is obtained. 12 each
Wash the cake with two portions of 0.01 pure methanol. Purity 97.8? 8 g of anthracene (calculated per anthracene, yield of 59.5'A based on the theoretical yield)
is obtained. The filtrate is vacuum distilled to recover 119.9% of N-methylgyrolidone.

Example 5 First step of crystallization: 217 g of a sample of anthracene oil having the composition and properties shown above are placed in a crystallizer as in Example 1. The anthracene oil is heated with circulating hot water in the heating jacket of the crystallizer to obtain a homogeneous liquid phase (its temperature is above 90° C.). Then, as in Example 1, thereby
Cool the oil until reaching the final crystallization temperature of . The contents of the crystallizer are kept at 70° C. for 1 hour and then the mother liquor is separated off in an amount of 167 g. In the crystallizer, it is deposited on the wall soil, and 5
Unpurified anthra7ane crystals remain with an amount of 0IiO. All of these were treated with 60 g of N-methylpyrrolidone in the same crystallizer at room temperature. After 6 hours, the contents of the crystallizer in the form of a suspension are filtered through a Puchner funnel and purified to give 106 g of filter H containing a cake of anthracene as well as N-methylpyrrolidone. Wash the cake with two portions of 12011j methanol each.

4 g of anthracene are obtained with a purity of 95.91 k. Combine this filtrate with the filtrate from the second round of total crystallization,
Use vacuum distillation to recover nine solvents.

Second Step of Crystallization The mother liquor 1671 from the first step of crystallization is charged into the vertical tubular crystallizer described above. The contents of the crystallizer are heated to a temperature of 70° C. to obtain a homogeneous phase. Then, as in Example 1, the oil is cooled down until a final crystallization temperature of 60° C. is reached.

The contents of the crystallizer were kept at 50°C for t1 hour and then heated to 100°C.
The residual oil is separated by tx force in an amount of g. The crystallizer remains with unpurified anthracene crystals in an amount of 67 g, deposited on the walls.

N-methylpyrrolidone 60
Process with 9. After 6 hours, the contents of the crystallizer in the form of a suspension were filtered through a Buchner funnel and 124 g of the filtrate containing a cake of purified anthracene and N-methylgyrolidone were obtained.
is obtained. The cake was washed with two portions of pure methanol, each containing 120 IIlj. 6 g of anthracene having a purity of 95.11t are obtained. This filtrate is combined with the filtrate from the first step of crystallization and used by vacuum distillation to recover the solvent. 119 g of N-methylgyrolidone are obtained.

Anthracene was obtained with a purity of 95.51, calculated per anthracene. ! Corresponding to a total yield of 1%.

Example 6 Sample 218.9 of anthracene oil containing the nine compositions and properties shown in Table 2 is placed in a crystallizer as in Example 1. The anthracene oil is heated with circulating hot water in the heating jacket of the crystallizer to obtain a homogeneous liquid phase (its temperature is above 90° C.). The oil is then cooled as in Example 1 until a final crystallization temperature of 50° C. is reached. The contents of the crystallizer are kept at 50 DEG C. for t-1 hours, after which the mother liquor is separated by gravity in an amount of 136 g. The crystallizer remains with unpurified anthracene crystals in an amount of 821, deposited on the walls. These were treated with N-methylpyrrolidone 1209 in the same crystallizer at room temperature. After 3 hours, the contents of the crystallizer in the form of a suspension were filtered through a Puchner funnel and a cake of purified anthracene as well as N-
189 g of methylpyrrolidone-containing filtrate are obtained. The cake is washed with three portions of 12,011 t each of pure methanol.

Anthracene 13I with a purity of 95% (calculated per anthracene, yield of 60.9% relative to the theoretical yield)
is obtained. The filtrate is vacuum distilled to obtain 119 g of N-methylgyrolidone.

The composition of the anthracene oil used in the experiments described in Examples 6 and 7 is: anthracene 9.6, phenanthrene 40.9, carnozole 6.8, determined by the UV/VI8 method in terms of component weight tqb.Example 7 A sample of 219.9 t of anthracene oil having the composition and properties shown in the table is placed in a crystallizer as in Example 1.

The anthracene oil is heated with circulating hot water in the heating jacket of the crystallizer to obtain a homogeneous liquid phase (its temperature is above 90° C.). Then, as in example 1, thereby 7
Cool the oil thoroughly until reaching the final crystallization temperature of 0°C. The contents of the crystallizer are kept at 70° C. for 1 hour, after which the mother liquor is separated by gravity in an amount of 1489. In the crystallizer, unpurified anthracene crystals remain in an amount of 71 g, deposited on the wall soil.

These were mixed with N-methylpyrrolidone 1 in the same crystallizer at room temperature.
Treat with 20g. After 3 hours, the contents of the crystallizer in the form of a suspension are filtered through a Puchner funnel and a cake of purified anthracene as well as a filtrate containing N-methylgyloride/1
77 g is obtained. The cake is washed with three portions of pure methanol of 120 Mlj each. 14 g of anthracene with a purity of 96.591 (yield of 66.2% based on the theoretical yield, calculated on anthracene) are obtained. The filtrate was vacuum distilled to give N-methylgyrolidone 119.
g is recovered.

Claims (14)

[Claims] (1) Anthracene oil in as dilute a form as possible is cooled to a temperature below 80°C in a vertical crystallizer with a cooling surface developed;
The residual oil is preferably separated by gravity, the crude anthracene crystals formed are treated with a neutral, dipolar solvent in the same crystallizer, and the purified anthracene is then removed from the solvent by filtration, centrifugation or other known methods. A process for the separation and purification of anthracene from coal tar raw materials by crystallization and solid-liquid extraction, characterized in that anthracene is separated from the suspension therein and the solvent is recovered and recycled to the process. (2) The method of claim 1, wherein the operation of cooling the anthracene oil in the crystallizer is repeated several times until at least half of the crystallizer volume is filled with crystals. (3) Anthracene oil before being introduced into the crystallizer contains linear and branched aliphatic and cycloaliphatic C_5-C_1_ in an amount of 20-100% by weight relative to the anthracene oil used.
2- Hydrocarbons and hydrocarbons of the general formula I ▲Mathematical formulas, chemical formulas, tables, etc.▼ (wherein R is a C_2-C_3 alkyl group and n is an integer within the range of 1 to 50), and naphthalene The method of claim 1, wherein the method is diluted with a solvent such as two or more substituted isopropyl derivatives of and mixtures thereof. (4) fractions of di- and polyalkylbenzenes from the benzene alkylation process with ethylene and propylene;
Process according to claim 3, wherein aliphatic volatile oils and pyrolysis oils or propylene oligomers are used as diluents. (5) Cooling of anthracene oil for 2-20 hours, 0-70
Claim (1) or (2) carried out at a temperature within the range of °C.
)the method of. (6) General formula II ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 is a hydrogen atom or a C_1-C_3-alkyl group, R_2 is a hydrogen atom, methyl group or ethyl group, and R_3 is a -C_3-alkyl group,
Furthermore, R_2 and R_3 are both C_3-C_5-alkylene groups, and R_1 and R_3 are both C_2-C_7
2. The process according to claim 1, wherein amides of -alkylene, oxaalkylene and azaalkylene groups are used as neutral, dipolar solvents. (7) A process according to claim 1, wherein an aliphatic sulfoxide such as dimethyl sulfoxide or an aliphatic nitrile such as acetonitrile or β-hydroxypropionitrile is used as the neutral, dipolar solvent. (8) N-methylpyrrolidone, N-methyl-caprolactam, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylformamide, N-formylmorpholine or a mixture thereof with water is a compound of general formula II The method of claim (6), wherein the method is used as a method. (9) The neutral, dipolar solvent is used at a temperature in the range of 20 to 60°C in an amount of 40 to 250% by weight relative to the crude anthracene crystals present in the crystallizer. )
Or method (6) or (7). (10) The isolated crystals of purified anthracene are first washed once or repeatedly with a neutral, dipolar solvent and then with a low boiling polar solvent and dried. Method. (11) The method of claim (10), wherein methanol, ethanol, water or a mixture thereof, and a mixture of acetone or methyl ethyl ketone and water are used as low boiling polar solvents for washing the purified anthracene. (12) The recovery of the neutral, dipolar solvent is carried out by vacuum distillation, its periodic purification is carried out by diluting it with water at a weight ratio of 1:1, and the separation of the precipitated solid phase is carried out by filtration, centrifugation or any other method. The method of claim (1), carried out by any other known method. 13. The method of claim 1, wherein a vertical tubular crystallizer is used comprising a bundle of metal tubes with an internal diameter in the range from 5 to 20 mm, cooled with water or brine flowing through the internal tubular space. (14) Claim (14) wherein the anthracene oil is prefiltered, in particular through a bed of filter aid such as coke breeze or through a slit filter with external removal of the separated cake.
Method 1).