DD207096A3 - METHOD OF OBTAINING A DICYCLOPENTADIATE CONCENTRATE - Google Patents

Abstract

The invention relates to a process for obtaining a Dicyclopentadienkonzentrates from a C down 5 / C lower 6 fraction was obtained in the pyrolysis of hydrocarbons and its supply to a further use. The object of the invention is to obtain a dicyclopentadiene concentrate by using a simple technology without vacuum and cooling equipment and an additional purification stage, according to the invention the C down 5 / C down 6 fraction either directly before entering the distillation column or as a separate production stream in the distillation column is added a certain amount of toluene and / or C below 8-aromatics and, if appropriate, water vapor. The dicyclopentadiene concentrate thus obtained can be used without further treatment as a starting material in the synthetic resin industry.

Description

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Process for obtaining a dicyclopentadiene concentrate

Field of application of the invention

The invention relates to a process for obtaining a Dicyclopentadienkonzentrates from a Cg / C -.- fraction, which was obtained as a liquid fraction in the pyrolysis of hydrocarbons and its supply to a further use.

Characteristic of the known technical solutions

The aim of the pyrolysis of liquid or gaseous hydrocarbons (KvV) in a known manner is the preferred recovery of lower olefins. A large number of pyrolysis products accumulates, ranging from water vapor to high-boiling KvV, such as pyrolysis oil. In a separation plant connected downstream of the pyrolysis plant, the resulting pyrolysis products are separated by fractional condensation and distillation in accordance with their boiling position. In principle, the following liquid fractions of pyrolysis products are obtained:

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Pyrolysis oil above 200 ⁰ C boiling

heavy pyrolysis gasoline 130 - 200 ⁰ C boiling

Compressor condensates 80 - 160 ⁰ C boiling

Cg / Cg fraction of the gas separation 30 - 90 ⁰ C boiling

The boiling between 30 ⁰ C and 200 ⁰ C fractions are generally and therefore also referred to below as pyrolysis gasoline.

Dicyclopentadiene (DCPD) is preferably obtained from the C tion of pyrolysis gas, boiling 30 C - 90 C. This fraction contains most of the 0 - KuV produced during pyrolysis, in addition to relatively large proportions of benzene. A typical composition is shown in the following table:

Table 1

On part Ma> -SK Boiling temperature ⁰ C 11 , - 13 Wt .-% 34 10 - 12 Wt .-% 40.8 19 - 23 Ma.-SK 80 ca , 10 170 - 182

isoprene

Cyclopentadiene (CPD ").

benzene

Dicyclopentadiene (DCPD) and Godiiiiere

Due to the thermal stress of the Cg / Cg fraction during the distillative separation processes, part of the CPD in this fraction is dimerized to DCPD.

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By further heat treatment at temperatures between and 130 C, it is possible to largely convert the CPD into the dimeric form. The dimerization reaction of CPD to DCPD is exploited by many methods for producing pure DCPD. The following steps are generally used:

1. Dimerization of CPD to DCPD in the starting fraction

2. Distillative separation of light KW from the formed DCPD

3. Monomerization of DCPD to CPD

4. Re-dimerization of the cleavage-induced CPD to pure DCPD

By other methods, the CPD is recovered from the C ₁ -ZCg fraction by extraction processes or by extractive distillation. The following solvents are mentioned in the literature:

Acetonitrile, furfurol, N-methylimidozole, N-methylpyrrolidone, dimethylformamide, aniline, and the like.

This list alone shows that considerable effort is needed to obtain CPD without prior dimerization to DCPD.

In the following, only the distillative separation of the light hydrocarbons from the DCP formed by dimerization should be considered here, since the invention relates to this distillative separation.

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In the patent literature, this process stage is little described, since this is a distillation process, which corresponds to the usual state of the art.

Due to the special properties of the products, however, there are some special features to consider. Thus, it is necessary to work in a vacuum because of the already beginning at 140 ⁰ C monomerization of 170 C boiling DCPD to CPD. If you want to lower the boiling point to 120 ⁰ C, so a pressure of 20 kPa is necessary. At such pressure, however, condensation of the light hydrocarbons to be distilled off with cooling water is no longer possible. Condensation of the light hydrocarbons with cooling water generally requires in the art condensation temperatures in excess of 45 C *. At the stated pressure of 20 kPa, however, the individual components of the C ₅ / C ~ fraction condense at the following temperatures:

^ -Hydrocarbons - 30 ⁰ C to - 5 ⁰ C Cg hydrocarbons 0 ⁰ C to + 25 ⁰ C

Benzene 35 ^° C

Therefore, refrigeration systems are used in the industry to condense the light hydrocarbons to be distilled off from the DCPD in vacuo.

The DCPD obtained in this distillation is then purified by the following additional process stages * by monomerization and renewed dimerization * The DCPO thus produced has a purity of over 95 % and serves as a raw material for the production of synthetic resins based on DCPD.

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Object of the invention

It is the object of the invention »a DCPD concentrate from a Cg / Cg fraction of pyrolysis gasoline which is suitable for the production of DCPD-based synthetic resins, by using a simple technology without vacuum and cooling equipment and without an additional purification stage to win.

Explanation of the essence of the invention

The problem solved by the invention

The object of the invention is to develop a process, according to which the distillative removal of the low-boiling components from a C ₅ / C _ß fraction of the pyrolysis gas *, in particular those of the Cg / Cg hydrocarbons, carried out under atmospheric pressure, avoids monomerization of the DCPD and a DCPD concentrate is obtained, as well as to use this without further processing for the production of resins based on DCPD.

Features of the invention

This object is achieved in accordance with the invention by carrying out the distillative recovery of DCPD from the Cg / Cg fraction of the pyrolysis gasoline by the customary dimerization of the CPD to DCPD in the presence of toluene and / or Cg aromatics. According to the invention, the addition of toluene and / or Cg aromatics takes place either directly into the Cg / Cg fraction before it enters the distillation column or as a separate product stream into the distillation column. .

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The amount of toluene and / or Cg aromatics should be adjusted so that the obtained in the bottom of the distillation column DCPD has a content of 5 to 20 Ma. -% toluene and / or Cg-containing aromatics. The distillation of the DCPD according to the invention from the C ₅ / C fraction of the pyrolysis gasoline in the presence of toluene and / or C 9 -aromatics permits the substantial removal of low-boiling hydrocarbons, in particular benzene, under such technological conditions, among which both the To avoid decomposition of the DCPD, as well as to avoid the use of vacuum and cooling equipment.

The distillative removal of the low-boiling products contained in the Cg / Cg fraction, in particular of benzene, otherwise only very incomplete under normal pressure conditions. Even at 'bottom temperatures of 150 C, the benzene content is still 3.5 wt .-% in the DCPD.

In no case has it been possible to date an enrichment of the DCPD in the bottom product of substantially more than 65 Ma. .-% to achieve. At bottom temperatures above 130 ⁰ C, the DCPD concentration drops even as a result of increasing onset of monomerization.

However, if the distillation is carried out according to the invention in the presence of toluene, the separation effect of the column is markedly improved. The concentration of DCPD, calculated on aromatics,. achieves values which are increased by about 10% by weight compared to the procedure without toluene addition. To achieve this effect, toluene contents in the bottom product range from 8 to 12 Ma. -% off. An increase in the toluene content leads to no significant improvement. The increase of the DCPD concentration in the bottom product

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by distillation in the presence of toluene is maintained even at temperatures at which enters without toluene addition already a strong monomerization of the DCPD. Even at bottom temperatures of 140 ⁰ C are still DCPD concentrations of 75 Ma. -% reached, while without addition of toluene, the DCPD concentration at this temperature is about 57% by mass. "

The addition of toluene achieves both an improvement in the separation effect and a delay in the monomerization of the DCPO.

A delay in the monomerization of the DCPD is also observed when the distillation is carried out with the addition of C _g aromatics.

Thus, in the distillation by addition of 6 % Cg-Aroraaten to the starting material at bottom temperatures of 140 to 150 ⁰ C DCPD concentrations of about 70 Ma. % , however, in a distillation without addition of Cg-aromatics, the DCPD content in the sump is only about 57% by mass. * An improvement of the separation of the benzene is not achieved due to the high boiling temperatures of the Cg aromatics.

The removal of benzene succeeds in this case, if in addition 3 to 20 Ma. % Water vapor, based on the starting material ,, are added to the distillation column. To reach z. B. in the presence of C _g -razing already at bottom temperatures of 105 to 130 ⁰ C benzene, the <1 Ma. -% .

The DCPD prepared according to the invention from the C ₅ / Cg fraction was investigated for its suitability for the production of synthetic resins based on DCPD.

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It was found that z. B, compared to the use of DCPD with a purity of ^ 95 Ma. -% did not deteriorate the properties during the production of a paint resin. The content of Cg-aromatics DCPD concentrate prepared in the invention is generally not in the production of artificial resins based on DCPD disturbing because z. B. in the polymerization or polycondensation reactions xylene used here as entrainer for the removal of water. Toluene and / or Cg aromatics also very often serve as solvents for DCPD based resins.

EXEMPLARY EMBODIMENTS

The invention will be explained in more detail below with reference to examples and supported by the following:

Example O

In a laboratory distillation, a C ^ / C ^ fraction of pyrolysis gas was distilled after prior dimerization of the CPD to DCPD and separation of lower boiling benzene hydrocarbons. The column had 17 trays. The product was added on the 7th floor. The column was operated with the following parameters:

Swamp temperature: 100 - 150 ⁰ C Inlet temperature :. 80 ⁰ C Column pressure: atmospheric Reflux ratio: 0.5

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96.7 g / h of a fraction having the following composition were fed into the column:

C ₅ / Cg hydrocarbons 3.1 Ma. -%

Benzene 33.7 Ma. -%

Toluene 1.6% by mass

Cy / Cg hydrocarbons 8.2% by mass

DCPD 38.4 Ma. -%

Codimers (including 15.0 Ma. % M-DCPD)

The bottom temperatures were varied between 110 ⁰ C and 150 ⁰ C. The following values were obtained:

120 130 140 65.0 57.3 50.0 41.6 16.6 9.8 6, a 3.5

bottom temperature ⁰ C 110 8th marsh amount g / n 75, 5 Benzene content in Ma. -SK 22, bottoms DCPD Konzentra 4 tion, calculated Ma. -% .64,

63.5 65.3 58.3 56.7 on benzene-free

example 1

The starting material according to Example 0 was admixed with 10 % by weight of toluene and distilled under the same conditions as in Example 0. 101.1 g / h of the abovementioned fraction were fed into the column. The following values were obtained:

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bottom temperature ⁰ C 130 3 140 150 marsh amount g / h 65 »7 50.9 49.7 benzene Ma.-S6 8th 2.6 0.13 toluene content Ma ..- * 14 19.6 17.9 DCPD Konzentra calculated on toluene and ben zol f rei Wt .-% 71 72.4 69.9 Example 2

The starting material according to Example 0 was admixed with the following amounts of toluene and

a) distilled at 130 ⁰ C bottom temperature

b) distilled at 140 C sump temperature.

The following analysis values of the bottom product were obtained:

toluene addition % b O 6. 10 20 benzene % a. 12 :, 5- 10.3 8.3 4.7 - b 6 * 3 4.3 2.6 0.19 toluene content - 10.0 14.7 29.9 - 12.5 19.6 30.5 DCPD Konzen tration be expects b toluene and 65.3 73.0 71.4 67 benzolefree 58.3 70.5 • 72.4 73.5

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Example 3

The starting material according to Example 0 was mixed with 5 % Cg aromatics and distilled at bottom temperatures of 140 ° C and 150 ⁰ C. There were 93 g / h of the above fraction fed into the column. The following analysis values of the bottom product were obtained:

temperature ⁰ C 140 150 marsh amounts g / h 43.1 41.2 benzene Ma.-SK 7.9 9.0 C ₀ aromatics Ma.-95 12.8 15.4 DCPD concentration calculated on C ₀ - O aromatics - and benzene-free Ma.-SS 68.6 70.1 DCPD concentration without Cg addition calculated to benzolfrei Ma. -% 58.3 56.7 Example 4

The starting material according to Example O 10 % Cg aromatics were added. During the distillation, water vapor was added to the bottom of the column in an amount of 10 % and 20 % respectively , calculated on the amount of feedstock. 470 g / h of the above fraction were fed into the column. The following analysis values of the bottom product were obtained:

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Bottom temperature ⁰ C 105 110 120 130

Steam-

additional Ma .-% 20 10 20 10 20 10

Swamp volumes g / h 242 290 199.5 266 171 237

Benzene content Ma, -% 1.5 3.4 0.4 2.3 0.3 1.3

Cg-aromatics

Ma .-% 14.7 17.1 8.1 16.1 8.8 12.0

DCPD con-

concentration

calculated

on Cg Aro

maten and

benzene-free. % By mass 72.6 70.8 71.9 69.5 72.2 70.4

Example 5

The produced DCPD concentrate according to the invention was used to prove suitability as a raw material for alkyd resin synthesis over pure DCPD. In a 5 l _r 1 glass vessel equipped with stirrer, thermometer, reflux condenser and metering 120 g of glycerol, 44 g of pentaerythritol and 147 g of maleic anhydride were initially heated to 120 ⁰ C and held for 30 minutes. This was followed by the addition of 198 g of pure DCPD (content greater than 97% by mass) for Resin A or 248 g of DCPD concentrate according to the invention of Example 1 with a benzene content <1 % for Resin B. The reaction mixtures were added for 2 hours

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150 ⁰ C stirred and then 214 g of safflower oil fatty acid and xylene as entrainer added as necessary and esterified at 200 ⁰ C until an acid value less than 20 rag KOH / g was reached. The resins were dissolved in xylene. The following key figures were obtained:

Resin A Resin B.

Acid number 16.6 rag KOH / g 15 _r 9 mg KOH / g

Viscosity 1510 m.Pa.s, 1550 m.Pa.s.

(60 % ± g in xylene)

Ood color number 5 rag 0_ / 100 ml 5 mg 0- / 100 ml

Resins A and B were combined with titanium dioxide R in the ratio pigment: binder = 1: 2 with the addition of 0.05 % Co and 0 ^ .5 % Pb (each in the form of their octoates) based on solid resin and 1 % of a conventional skin preventive grated white paint. The test as an air-drying coating on sheet and glass was carried out in a layer thickness of 35y ^ tm, achieved characteristics:

Resin A Resin B

Drying according to TGL 14 301/3

1.75 h 15.5 h

102 s

Drying grade 1 2 H Drying grade 4 15 H Pendulum hardness after TGL 29,771 98 S after 8 days Shine after TGL 107-06104 / 1 100 %

102 %

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- 14 resin A resin B

Erichsen

TGL 14 302/3 6.3 mm 6.2 mm

The achieved key figures and coating test results prove the suitability of the inventive DCPD concentrate as raw material for synthetic resin synthesis.

Claims (6)

233483 3 Invention claim 1. A process for obtaining a DCPD concentrate from a Cg / Cr. Fraction of a pyrolysis gasoline which is obtained in a pyrolysis of liquid or gaseous hydrocarbons, by oimerization of cyclopentadiene and subsequent separation by distillation öer_ .leichtsiedenden. Hydrocarbons, in particular of benzene, characterized in that the distillative removal of aer low -boiling hydrocarbons in the presence of toluene and / or Cg ~ AroiTiaten at atmospheric pressure and the resulting DCPD concentrate is fed without further purification by repeated monomerization and dimerization its further use. A process for obtaining a DCPD concentrate according to item I _1, characterized in that the addition of toluene and / or Cg aromatics takes place before a distillation column in the feedstock of the distillation or as a separate production stream directly into the distillation column. 233463 3 3. A process for obtaining a DCPD concentrate according to item 1 and 2, characterized in that the addition of toluene and / or Cg-aromatics is carried out in the amount that in the DCPD concentrate, a content of toluene and / or Cg-aromatics from 5 to 30 Ma. -% setting. 4. A process for obtaining a DCPD concentrate according to item 1 to 3, characterized by ,, that in the bottom of the distillation column additionally steam in an amount of 3 to 20 wt .-%, based on the amount of starting product, is introduced. 5. A process for obtaining a DCPD concentrate according to item 1 to 4, characterized in that the bottom temperature, the amount of added toluene and / or the added C "aromatics and optionally the addition of water vapor are coordinated so that the benzene content preferably 1 Ma. -% does not exceed. 6. A method for obtaining a DCPD concentrate according to item 1 and 5, characterized in that the recovered DCPD concentrate for the production of synthetic resins based on DCPD is used.