RU2540329C1 - Method of producing cyclopentadiene - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing cyclopentadiene, which comprises monomerisation of a dicyclopentadiene-containing fraction in the presence of an inert high-boiling solvent and a polymerisation inhibitor. The initial dicyclopentadiene-containing fraction with total concentration of dicyclopentadiene and cyclopentadiene of 80-98 wt % is mixed with a recycle stream to achieve total concentration of dicyclopentadiene and cyclopentadiene of 50-97 wt %, and monomerisation is carried out in the presence of dodecane in weight ratio of dicyclopentadiene:solvent of 40:60 to 90:10, and alkylphenol, which is added in concentration of 0.01-0.5 wt %, to dicyclopentadiene conversion of 99.4%. The method includes regeneration of the high-boiling solvent, separating the unreacted dicyclopentadiene at 115-180°C and pressure of 4-12 kPa and subsequent recycling thereof.

EFFECT: use of the invention increases concentration of cyclopentadiene in the end product, increases conversion of dicyclopentadiene with high output of cyclopentadiene and improves technological effectiveness of the process.

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Description

The invention relates to petrochemistry, and specifically to a method for producing cyclopentadiene from a dicyclopentadiene-containing fraction, including impurities of cyclopentadiene co-dimers with diene hydrocarbons. Cyclopentadiene is used to produce dicyclopentadiene, hexachlorocyclopentadiene, cyclopentane, cyclopentene, metallocenes and other compounds of the cyclopentane and norbornene series. Cyclopentadiene is used for the production of various petrochemical products: synthetic ethylene-propylene rubbers, resins, flame retardant paints, pesticides, jet fuels.

Synthetic methods for the production of cyclopentadiene, characterized by low conversion and selectivity due to the occurrence of side reactions, high temperatures, energy intensity and multi-stage technologies, have not found industrial application.

On an industrial scale, methods for the isolation of cyclopentadiene by the monomerization of dicyclopentadiene contained in petrochemical and coke-chemical feedstock are widespread. The decomposition of dicyclopentadiene can in principle be carried out both thermally and catalytically.

A known method of catalytic monomerization of a cyclopentadiene dimer at a temperature of 150-250 ° C in the presence of a pre-activated nickel-chromium catalyst. The activation of the catalyst is carried out by passing hydrogen in a volume ratio of catalyst to hydrogen of 1: (2000-3000) at a temperature of 150-200 ° C. The following is the treatment of the catalyst with air at a volume ratio of catalyst: air equal to 1: (0.11-0.21). RU 2007378 C1, C07C 13/15, 02.15.1994.

The catalytic process of monomerization allows to obtain cyclopentadiene with a concentration of up to 99.2 mass. % Significant disadvantages of the proposed technology are the complexity and energy intensity of the processes of synthesis, activation and regeneration of the catalyst, as well as the high toxicity of the catalyst.

The most widespread are the processes of thermal decomposition of dicyclopentadiene, which can be carried out both in the gas and in the liquid phase.

A known method of producing cyclopentadiene from hydrocarbons by three-stage dimerization of a cyclopentadiene-containing fraction in the liquid phase at a temperature of 125-140 ° C, monomerization of the dimeric fraction and isolation of the target product. SU 596565, C07C 7/01, 03/05/1978.

In the known method, the monomerization process is carried out in the presence of an inert solvent (boiling point 60-120 ° C) at a temperature of 400 ° C followed by separation of cyclopentadiene from an inert solvent by distillation (pressure 0.1 MPa, top temperature 45 ° C, cube temperature 85 ° C ) Get cyclopentadiene with a basic substance content of 99.0-99.8 mass. %

The specified method is characterized by the need to generate superheated water vapor used as a coolant, and high temperatures of the monomerization stage, leading to gum formation, thermal degradation of an inert solvent and, as a consequence, to reduce the efficiency of the process.

A known method of producing cyclopentadiene of high purity by monomerization of dicyclopentadiene with a basic substance content of 80-85 mass. % or concentrated dicyclopentadiene with a basic substance content of about 90 mass. % at a temperature of 140-250 ° C, mainly 180-190 ° C, and a residence time of the contact solution in the reactor of 0.1-6 hours, mainly 1-3 hours. The target product, separated by distillation, contains 99.4 wt. % of the main substance. CS 276654, C07C 13/15, 05.20.1992.

The disadvantage of this technology is the process of monomerization and separation of the obtained monomerizate in various devices, which leads to a long contact time of the obtained cyclopentadiene with dicyclopentadiene in the reaction mass at high temperature, which in turn causes increased gum formation and a decrease in the selectivity and yield of cyclopentadiene.

A known method of monomerization of dicyclopentadiene (the content of the main substance 89.9 wt.%) In the presence of a mixture of alkyl substituted phenols (2,6-ditretbutylphenol, 2,4-ditretbutylphenol, 2,4,6-tritrebutylphenol) at 165-180 ° C. RU 2289564 C2, C07C 2/42, C07C 13/61, 12.20.2006.

The disadvantages of this method are the low selectivity of the monomerization stage (94-96%) and the yield of the target product (91-92%), the need for additional energy consumption at the melting stage of a mixture of tert-butyl substituted phenols, which are crystalline substances.

A known method of monomerization of a dicyclopentadiene-containing fraction (the content of the basic substance is 83.4-95.7 wt.%), Which is carried out in the presence of a mixture of alkyl- and aryl-substituted phenols in a mass ratio (50-70) :( 50-30), respectively introduced in an amount 10-20 mass. % to dicyclopentadiene-containing fraction, at a temperature of 165-185 ° C. As alkyl substituted phenols use Agidol-21 (TU 2425-452-05742686-2003), which is a mixture of mono - and dialkylphenols. As aryl substituted phenols use Agidol-20 (TU 38103160-91), which is a mixture of methylbenzylphenols. The phenol mixture is preheated in a recuperative heat exchanger with the bottom products of the monomerization column. RU 2463284 C1, C07C 13/61, C07C 7/20, C07C 2/42, C07C 2/50, 10/10/2012.

This method allows to obtain cyclopentadiene with a basic substance content of 91.54-99.32 mass. % The known method is not sufficiently effective due to low selectivity (94-96%) and the yield of the target product (91-92%).

The closest in technical essence is the method of producing dicyclopentadiene, which involves the production of cyclopentadiene by monomerization of dicyclopentadiene in the presence of a high boiling solvent and a polymerization inhibitor at a temperature of 180-210 ° C. Dicyclopentadiene with a basic substance content of 83.8-88.8 mass. % obtained at the stage of fractionation of the dimerized C ₅ fraction. Heptadecane is used as a high boiling solvent, and ditolylmethane can also be used. Hydroquinone is used as a polymerization inhibitor, and benzoquinone can also be used. RU 2186051 C1, C07C 13/61, 07.27.2002.

The disadvantages of this method are the low purity of the resulting cyclopentadiene product (86.44 wt.%) With a mass concentration of dicyclopentadiene in the feed fraction of less than 84.0%, insufficient conversion of dicyclopentadiene (88.0-90.0%), and high toxicity of ditolylmethane.

An object of the present invention is to develop a method for producing highly concentrated cyclopentadiene by monomerizing a dicyclopentadiene-containing fraction, including impurities of cyclopentadiene co-dimers with diene hydrocarbons, in the presence of an inert high-boiling solvent and a polymerization inhibitor with recirculation of unreacted dicyclopentadiene and recycle streams.

The technical result from the implementation of the invention consists in increasing the conversion to 99.4% and the selectivity of the process to 99.5% while increasing the concentration of cyclopentadiene in the target stream to 99.9 mass. % The recycling of unreacted dicyclopentadiene and high boiling solvent streams can reduce the potential environmental impact, as well as improve the processability. Cyclopentadiene is a finished product and is used as a raw material for the production of valuable petrochemical products, primarily dicyclopentadiene with a concentration of more than 98.5 mass. %

The method is illustrated by the following diagram presented in figure 1.

Dicyclopentadiene monomerization is carried out in a plant consisting of a monomerization reactor (P-1), which is a distillation column with an increased volume of bottoms, as well as a distillation column for the inert high-boiling solvent regeneration and separation of unreacted dicyclopentadiene (K-1). The initial raw material dicyclopentadiene-containing fraction (1) with a total concentration of dicyclopentadiene and cyclopentadiene in the range from 80 to 98 mass. % mixed with recycle stream (7). The resulting feed stream (2) with a total concentration of dicyclopentadiene and cyclopentadiene in the range from 50 to 97 mass. % is fed to the reactor (P-1), where dicyclopentadiene is monomerized at a temperature of 180-210 ° C. An inert high boiling solvent is introduced into the lower section of the reactor (P-1) together with a polymerization inhibitor (3) to control the temperature of the monomerization process, reduce gum formation and prevent the cyclopentadiene oligomerization process. The mass ratio of dicyclopentadiene: solvent is from 40:60 to 90:10. The polymerization inhibitor is served in a concentration of from 0.01 to 0.5 mass. % The average residence time of the contact solution in the reaction zone is 2-5 hours. The obtained cyclopentadiene from the lower part of the reactor (P-1) passes through mass transfer devices to separate it from heavy boiling impurities and solvent, after which high-purity cyclopentadiene (4) is removed from the upper part of the reactor (P -one). Fraction (5), consisting mainly of a high boiling solvent, impurities and unreacted dicyclopentadiene, is taken from the bottom of the monomerization reactor (P-1) and sent to regeneration of the high boiling agent and separation of unreacted dicyclopentadiene to a distillation column (K-1). The distillation column (K-1) operates at a pressure of 4-12 kPa and a bottom temperature of 115-180 ° C. From the top of the column (K-1), fraction (6) containing dicyclopentadiene was selected. A portion of the obtained fraction (6) in an amount of 50-95 mass. % return by recycling (7) to the inlet of the reactor (P-1), the remaining part (8) is taken out of the system for disposal. An inert high-boiling solvent (9) with a basic substance content of 90.0-99.9 mass is selected from the middle part of the distillation column (K-1). % and return it to the inlet of the reactor (P-1). The bottoms product (10) of the distillation column (K-1) contains heavy impurities.

The invention is illustrated by the following examples of specific performance.

Example 1. The initial raw material dicyclopentadiene-containing fraction (1) with a total concentration of dicyclopentadiene and cyclopentadiene of 95.8 wt. % mixed with the recycle stream (7) until the total concentration of dicyclopentadiene and cyclopentadiene 82.4 wt. % and sent to the monomerization reactor (P-1). A polymerization inhibitor and an inert high boiling solvent (3) mixed with a recycle stream of the regenerated solvent (9) are also fed there. The mass ratio of dicyclopentadiene: solvent is 70:30. The concentration of the polymerization inhibitor in the contact solution is maintained at 0.1 mass. % As a high-boiling solvent dodecane with a concentration of the main substance of 99 mass. % As a polymerization inhibitor, para-tert-butylcatechol with a basic substance concentration of 99 masses is used. % In the reactor (P-1) at a temperature of 195 ° C and an average residence time of the contact solution in the reactor of 4 hours, dicyclopentadiene monomerizes. The resulting cyclopentadiene (4) after separation of heavy impurities on the mass transfer devices is discharged through the upper section of the reactor (P-1). The concentration of cyclopentadiene in the target stream (4) is 99.90 mass. % yield 98.8%. The bottom stream (5) from the monomerization reactor (P-1) is sent to a distillation column (K-1) to regenerate the solvent and separate the unreacted dicyclopentadiene. The distillation column (K-1) operates at a pressure of 4 kPa and a bottom temperature of the column of 115 ° C. From the top of the column (K-1), fraction (6) containing unreacted dicyclopentadiene, some of which in the amount of 80 wt. % return by recycling (7) to the inlet of the reactor (P-1), and the remaining part (8) is taken out of the system for disposal. From the middle part of the column (K-1) dodecane (9) is selected with a content of the main substance of 99 mass. % and return it to the inlet of the reactor (P-1). A heavy residue (10), consisting mainly of cyclopentadiene oligomers, is taken from the column cube (K-1) and sent for disposal.

Example 2. The raw material and high boiling solvent for the monomerization of dicyclopentadiene are similar to example 1.

The initial raw material dicyclopentadiene-containing fraction (1) is mixed with the recycle stream (7) until the total concentration of dicyclopentadiene and cyclopentadiene reaches 82.6 mass. % and sent to the monomerization reactor (P-1). A polymerization inhibitor and an inert high boiling solvent (3) mixed with a recycle stream of the regenerated solvent (9) are also fed there. The mass ratio of dicyclopentadiene: solvent is 80:20. The concentration of the polymerization inhibitor in the contact solution is maintained at 0.1 mass. % As a polymerization inhibitor, di-tert-butylphenol is used. In the reactor (P-1) at a temperature of 190 ° C and an average residence time of the contact solution in the reactor for 5 hours, dicyclopentadiene monomerizes. The resulting cyclopentadiene (4) after separation of heavy impurities on the mass transfer devices is discharged through the upper section of the reactor (P-1). The concentration of cyclopentadiene in the target stream (4) is 99.83 mass. % yield 98.5%. The bottom stream (5) from the monomerization reactor (P-1) is sent to a distillation column (K-1) to regenerate the solvent and separate the unreacted dicyclopentadiene. The distillation column (K-1) operates at a pressure of 8 kPa and a bottom temperature of 150 ° C. From the top of the column (K-1), fraction (6) containing unreacted dicyclopentadiene, some of which in the amount of 80 wt. % return by recycling (7) to the inlet of the reactor (P-1), and the remaining part (8) is taken out of the system for disposal. From the middle part of the column (K-1) dodecane (9) is selected with a content of the main substance of 99 mass. % and return it to the inlet of the reactor (P-1). A heavy residue (10), consisting mainly of cyclopentadiene oligomers, is taken from the bottom of the column (K-1), which is sent for recycling.

Example 3. A high boiling solvent and a polymerization inhibitor for dicyclopentadiene monomerization are similar to Example 1.

The initial raw material dicyclopentadiene-containing fraction (1) with a total concentration of dicyclopentadiene and cyclopentadiene of 94.1 mass. % is mixed with the recycle stream (7) until the total concentration of dicyclopentadiene and cyclopentadiene reaches 76.9 mass. % and sent to the monomerization reactor (P-1). A polymerization inhibitor and an inert high boiling solvent (3) mixed with a recycle stream of the regenerated solvent (9) are also fed there. The mass ratio of dicyclopentadiene: solvent is 70:30. The concentration of the polymerization inhibitor in the contact solution is maintained at 0.02 mass. % In the reactor (P-1) at a temperature of 191 ° C and an average residence time of the contact solution in the reactor for 2 hours, dicyclopentadiene monomerizes. The resulting cyclopentadiene (4) after separation of heavy impurities on the mass transfer devices is discharged through the upper section of the reactor (P-1). The concentration of cyclopentadiene in the target stream (4) is 99.80 mass. % at the exit of 98.5 mass. % The bottom stream (5) from the monomerization reactor (P-1) is sent to a distillation column (K-1) to regenerate the solvent and isolate unreacted dicyclopentadiene. The distillation column (K-1) operates at a pressure of 10 kPa and a bottom temperature of the column of 160 ° C. From the top of the column (K-1), fraction (6) containing unreacted dicyclopentadiene, some of which in the amount of 80 wt. % return by recycling (7) to the inlet of the reactor (P-1), and the remaining part (8) is taken out of the system for disposal. From the middle part of the column (K-1) dodecane (9) is selected with a content of the main substance of 99 mass. % and return it to the inlet of the reactor (P-1). A heavy residue (10), consisting mainly of cyclopentadiene oligomers, is taken from the bottom of the column (K-1), which is sent for recycling.

Example 4. A high boiling solvent for the monomerization of dicyclopentadiene is similar to example 1.

The initial raw material dicyclopentadiene-containing fraction (1) with a total concentration of dicyclopentadiene and cyclopentadiene of 83.4 mass. % are mixed with the recycle stream (7) until the total concentration of dicyclopentadiene and cyclopentadiene reaches 50.6 mass. % and sent to the monomerization reactor (P-1). A polymerization inhibitor and an inert high boiling solvent (3) mixed with a recycle stream of the regenerated solvent (9) are also fed there. The mass ratio of dicyclopentadiene: solvent is 70:30. The concentration of the polymerization inhibitor in the contact solution is maintained at 0.1 mass. % As a polymerization inhibitor, di-tert-butyl methylphenol is used. In the reactor (P-1) at a temperature of 192 ° C and an average residence time of the contact solution in the reactor of 4 hours, dicyclopentadiene monomerizes. The resulting cyclopentadiene (4) after separation of heavy impurities on the mass transfer devices is discharged through the upper section of the reactor (P-1). The concentration of cyclopentadiene in the target stream (4) is 99.85 mass. % yield 98.9%. The bottom stream (5) from the monomerization reactor (P-1) is sent to a distillation column (K-1) to regenerate the solvent and separate the unreacted dicyclopentadiene. The distillation column (K-1) operates at a pressure of 12 kPa and a bottom temperature of 180 ° C. From the top of the column (K-1), fraction (6) containing unreacted dicyclopentadiene, some of which in the amount of 80 wt. % return by recycling (7) to the inlet of the reactor (P-1), and the remaining part (8) is taken out of the system for disposal. From the middle part of the column (K-1) dodecane (9) is selected with a content of the main substance of 99 mass. % and return it to the inlet of the reactor (P-1). A heavy residue (10), consisting mainly of cyclopentadiene oligomers, is taken from the bottom of the column (K-1), which is sent for recycling.

Example 5. (According to the prototype.) The raw materials and conditions for the dicyclopentadiene monomerization are similar to Example 4. The monomerization process is carried out without solvent regeneration and separation of unreacted dicyclopentadiene in accordance with the traditional process scheme shown in Fig.2.

Get cyclopentadiene, the mass concentration of which is 99.85% with a yield of 96.6%. The conversion of raw materials is 97.1%.

Example 6. The raw materials and conditions for the monomerization of dicyclopentadiene are similar to Example 1. The monomerization process is carried out without regeneration of the solvent and separation of unreacted dicyclopentadiene in accordance with the traditional scheme of the process shown in figure 2.

Get cyclopentadiene, the mass concentration of which is 99.90% with a yield of 96.2%. The conversion of raw materials is 96.7%.

The data in examples 1-6 are shown in tables 1 and 2.

From examples 1-4 it is seen that the process of obtaining dicyclopentadiene according to the scheme, including the regeneration of a high-boiling solvent and separation of unreacted dicyclopentadiene at the stage of monomerization followed by recycling, allows for 50.6-82.6 wt. % increase the conversion of dicyclopentadiene to 99.0-99.4% with a selectivity of 99.5%, which corresponds to a yield of cyclopentadiene of 98.5-98.9% at a concentration of cyclopentadiene in the target stream of 99.8-99.9 mass. %

As can be seen from examples of specific performance 5 and 6, carrying out the process of producing cyclopentadiene without regenerating an inert high boiling solvent and separating unreacted dicyclopentadiene does not provide a high yield of the target product, since with 99.5% monomerization selectivity, the conversion of dicyclopentadiene is 96.7-97.1% . The output of cyclopentadiene in example 5 is 96.6%, in example 6 - 96.2%.

The set of features of the claimed object allows to obtain from dicyclopentadiene-containing fraction with a concentration of 50.6-82.6 mass. % cyclopentadiene with a concentration of 99.8-99.9 mass. %, which is used to obtain dicyclopentadiene, hexachlorocyclopentadiene, compounds of the cyclopentane and norbornene series and the production of a wide range of petrochemical products. The inventive method allows to increase the yield of cyclopentadiene in the target stream to 98.9% by increasing the conversion to 99.4% and the selectivity of the process to 99.5%.

Table 1 The parameters of the process for producing cyclopentadiene Example No. The concentration of DCPD and CPD in the initial fraction (1), mass. % The concentration of DCPD and CPD in raw materials (2) at the inlet to the reactor R-1, mass. % Mass ratio of DCPD: solvent at the inlet to the reactor R-1 The concentration of the inhibitor at the entrance to the reactor R-1, mass. % Temperature in the lower section of the R-1 reactor, ° C The average residence time in the reactor R-1, h The temperature of the bottom of the column K-1, ° C The pressure in the column K-1, kPa The output of the CPU,% Selectivity,% Conversion% one 95.8 82,4 30,0 0.1 195 four 115 four 98.8 99.5 99.3 2 95.8 82.6 20,0 0.1 190 5 150 8 98.5 99.5 99.0 3 94.1 76.9 30,0 0.02 191 2 160 10 98.5 99.5 99.0 four 83,4 50.6 30,0 0.1 192 four 180 12 98.9 99.5 99,4 5 83,4 83,4 30,0 0.1 192 four - - 96.6 99.5 97.1 6 95.8 95.8 30,0 0.1 194 four - - 96.2 99.5 96.7

table 2 Compositions of incoming, outgoing and intermediate streams of the cyclopentadiene production process Example No. The composition of the incoming flows, wt.% one 3 DCPD + CPD isoprene + piperylene co-dimers oligomers solvent impurities one 95.80 0.00 4.20 0.00 99.00 1.00 2 95.80 0.00 4.20 0.00 99.00 1.00 3 94.10 0.00 5.90 0.00 99.00 1.00 four 83.40 0.00 16.60 0.00 99.00 1.00 5 83.40 0.00 16.60 0.00 99.00 1.00 6 95.80 0.00 4.20 0.00 99.00 1.00 Example No. The compositions of the outgoing and intermediate flows, wt.% four 5 10 JRC isoprene + piperylene DCPD co-dimers solvent oligomers DCPD co-dimers solvent oligomers one 99.90 0.10 4.30 27.60 67.40 0.60 0.00 0.00 4.90 95.10 2 99.83 0.17 8.10 37.40 53.60 0.90 0.00 0.00 2.90 97.10 3 99.80 0.20 5.30 52.50 61.10 0.50 0.00 0.00 5.30 94.70 four 99.85 0.15 1,60 52.50 45.60 0.30 0.00 0.00 7.80 92.20 5 99.85 0.15 3.90 26.70 68.70 0.70 - - - - 6 99.90 0.10 6.20 8.30 84.50 0.90 - - - -

Claims (2)

1. A method of producing cyclopentadiene, comprising the monomerization of a dicyclopentadiene-containing fraction in the presence of an inert high-boiling solvent and a polymerization inhibitor, characterized in that the initial dicyclopentadiene-containing feed fraction with a total concentration of dicyclopentadiene and cyclopentadiene of 80-98 mass. % mixed with the recycle stream until the total concentration of dicyclopentadiene and cyclopentadiene 50-97 wt. %, and monomerization is carried out in the presence of dodecane in a mass ratio of dicyclopentadiene: solvent from 40:60 to 90:10, and alkyl phenol, introduced at a concentration of 0.01-0.5 mass. %, to the conversion of dicyclopentadiene to 99.4%, while the high-boiling solvent is regenerated, the unreacted dicyclopentadiene is separated at a temperature of 115-180 ° C and a pressure of 4-12 kPa and their subsequent recycling. 2. The method according to claim 1, characterized in that para-tert-butylcatechol, di-tert-butylphenol or di-tert-butyl methylphenol is used as alkylphenol.

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