WO2002036529A1 - Production method of dicyclopentadiene from c5-fraction of hydrocarbon pyrolysis - Google Patents

Abstract

A production method of a highly pure dicyclopentadiene usable in the production of resins and nornbornene derivatives from C5-fraction of hydrocarbon pyrolysis which comprises the steps of: dimerization of cyclopentadiene contained in C5-fractions by heating at the temperature of 50-110 °C to 95 % conversion to form a dimerized mixture; separating said dimerized mixture into a pure dicyclopentadiene by fractionation; monomerization of the said a pure dicyclopentadiene in the presence of a high-boiling solvent and a polymerization inhibitor at the temperature of 180-210 °C to form a monomerized mixture; separating said monomerized mixture into a pure cyclopentadiene by fractionation; dimerization of said a pure cyclopentadiene by heating at the temperature of 50-110 °C to 90-99 % conversion to form a dicyclopentadiene-enriched effluent; separating said a dicyclopentadiene-enriched effluent into a highly pure dicyclopentadiene by fractionation and wherein a highly pure dicyclopentadiene has a purity of at least about 99.5 %.

Description

PRODUCTION METHOD OF DICYCLOPENTADIENE

FROM C₅-FRACTION OF HYDROCARBON PYROLYSIS.

FIELD OF THE INVENTION

The present invention relates to petrochemistry and more specifically to

the production method of a highly pure dicyclopentadiene (DCPD) that can be

used for production of modified ethylene-propylene copolymers, DCPD

polymers and norbornene derivatives.

BACKGROUND OF THE INVENTION

German Pat. No. 2,334,633 discloses the production method of a pure

DCPD by dimerization of C₅-fraction containing cyclopentadiene (CPD). In this

method, a pure DCPD is produced by means of dimerization followed by

distillation to remove light boiling admixtures in the presence of toluene. The purified DCPD produced by this method can be used in some limited

application without additional purification because of its low purity. Only the

light boiling admixtures can be separated by in this method, but it is difficult

to separate co-dimers of CPD with isoprene or piperylene which have a close

boiling point of DCPD by distillation. The maximum purity of DCPD produced

by this method is only 85 %. Because the required purity of DCPD for modified

ethylene-propylene copolymers, DCPD polymers and norbornene derivatives is

more than 98.5 %, the DCPD produced above method cannot be used for the

above purpose.

The level of purity can be increased by further dimerization of a pure

CPD produced by monomerization of DCPD followed by distillation, because

the co-dimerization rate of CPD with isoprene or piperylene is significantly less

than the dimerization rate of CPD. U.S. Pat. No. 3,772,396 discloses the purity

of DCPD in this method is up to 99 %. But, this method has a difficulty in

operation, because a large amount of coke materials blocking pipes and coolers

is formed during vapor phase cracking of DCPD.

Russia Pat. No. 2,059,595 discloses the production method of a pure

DCPD from a C₅-fraction produced by hydrocarbon pyrolysis. According to this method, the process comprises the following steps. Firstly, a pure DCPD is

produced by Cs-fraction dimerization followed by separation of light boiling

hydrocarbons with distillation. Secondly, a pure CPD is produced by cracking

of the pure DCPD followed by further rectification. Lastly, a pure CPD

produced in second step is again dimerized to DCPD and the dimerized mixture

is rectified to highly pure DCPD. hi this method, Cs-fraction is dimerized at

110-135 °C, and the DCPD is monomerized in the medium of water vapor at the

temperature of 300-370 °C, the pressure of 0.16 MPa. The monomerized

product is rectified to separate a pure CPD by two rectification column at the

temperature of 140-300 °C. The maximum purity obtained by above method is

94 %. It was also reported that Cs-fraction is usually dimerized at 135°C

(Nostrikova N.Ν., Chernikh S.P., Grigoriev A.A., "Petrochemical CPD and

DCPD - perspective raw material for organic synthesis", CNIITENeftekhim,

1984, p. 7). The disadvantages of the above method are as follows,

1 insufficient purity level of DCPD, 2)complication of the process, and 3)high

energy consumption.

In the present invention, the main problems were solved successfully by

adaptation new optimum conditions of operation. DETAILED DESCRIPTION OF THE INVENTION

The purpose of the present invention are directed to increasing of the

purity level of DCPD, simplifying of the production process and reducing of

energy consumption.

The issued technical problems are solved by the following production method of

DCPD from a Cs-fraction of hydrocarbon pyrolysis; 1) dimerization of CPD in

Cs-fraction by heating, 2) production of a pure DCPD by fractionation to

remove a light boiling hydrocarbons, 3) monomerization of a pure DCPD, 4)

dimerization of a pure CPD, 5) rectification of dimerized mixture to a highly

pure DCPD. In above method, Cs-fraction dimerization is conducted at 40-150

°C, preferably 50-135 °C, more preferably 50-110 °C till the conversion

reaches 95 %, and monomerization of DCPD is conducted in the presence of

high-boiling solvent , preferably heptadecane and polymerization inhibitor,

preferably hydroquinone at 160-250 °C, preferably 180-210 °C. Then, a produced CPD is dimerized at 40-150 °C, preferably 50-135 °C, more

preferably 50-60 °C till the conversion reaches 90-99 %.

By means of the present invention, the purity level of DCPD is

increased up to 99.5-100 %, the number of process stages is reduced, and

energy consumption is lowered.

In this invention, Cs-fraction with boiling temperature of 25-70 °C and

the following compositions is used as feedstock.

Compound Contents, weight %

Cyclopentane 4.3-10.3

Isopentane 6.6-12.6

N-pentane 5.9-15.9

Pentene-1 2.2- 4.2

2-Methylbutene-l 3.9- 7.9

2-Methylbutene-2 2.7- 4.7

Pentene-2 (cis- and trans-) 2.8- 4.8

Piperylene (cis- and trans-) 12.8-20.8 Isoprene 10.9-22.9

DCPD/CPD 9.4-17.4

Cyclopentene 2.5-3.5

"Heavy" (C₆) 2.5-6.5

EXAMPLE 1

CPD in the Cs-fraction was dimerized in the reactor at 50 °C till CPD

conversion reached about 95 %. Then, the reaction mixture was fractionated

with two columns for separation of light boiling hydrocarbons from the top of

the first column and for separation a pure DCPD from the top of the second

column. The produced DCPD was monomerized in the presence of heptadecane

as a high-boiling solvent and hydroquinone as a polymerization inhibitor at 180-

210 °C. Then, the produced CPD was dimerized at 50 °C till the conversion

reached about 99 %. The dimerized mixture was rectified with two rectification

columns to separate a highly pure DCPD. By the aforementioned method,

DCPD having more than 99.5 % purity was produced with a yield of 77 %.

Table 1 shows the results of examplel. Tablel

EXAMPLE 2

CPD in the Cs-fraction was dimerized in the reactor at 110 °C till

conversion reached about 95 %. Then, the reaction mixture was fractionated

with two columns for separation of light boiling hydrocarbons from the top of

the first column and for separation a pure DCPD from the top of the second

column. The produced DCPD was monomeried in the presence of heptadecane

as a high-boiling solvent and hydroquinone or benzoquinone as a polymerization inhibitor at 180-210 °C. Then, the produced CPD was dimerized

at 60 °C till conversion reached about 92 %. The dimerized mixture was

rectified with two rectification columns to separate a highly pure DCPD. By the

aforementioned method, DCPD having more than 100 % purity was produced

with a yield of 75 %. Table2 shows the results of example2.

Table2

Claims

What is claimed is:

1. A production method of a highly pure dicyclopentadiene from a Cs-

fraction of hydrocarbon pyrolysis which comprises the steps of:

a. dimerization of cyclopentadiene contained in Cs-fractions by heating at the

temperature of 50-110 ^°C to 95 % conversion to form a dimerized

mixture;

b. separating said dimerized mixture into a pure dicyclopentadiene by

fractionation;

c. monomerization of the said a pure dicyclopentadiene in the presence of a

high-boiling solvent and a polymerization inhibitor at the temperature of

180-210 ^°C to form a monomerized mixture;

d. separating said monomerized mixture into a pure cyclopentadiene by

fractionation;

e. dimerization of said a pure cyclopentadiene by heating at the temperature

of 50-110 ^°C to 90-99 % conversion to form a dicyclopentadiene-enriched

effluent;

f. separating said a dicyclopentadiene-enriched effluent into a highly pure dicyclopentadiene by fractionation and wherein a highly pure dicyclopentadiene

has a purity of at least about 99.5 %.

2. The process according to claim 1 wherein dimerization in step (a) is

conducted at the temperature of 50-70 ^°C .

3. The process according to claim 1 wherein dimerization in step (e) is

conducted at the temperature of 50-60 ^°C .

4. The process according to claim 1 wherein a high-boiling solvent in step (c)

is heptadecane.

5. The process according to claim 1 wherein a polymerization inhibitor in

step (c) is hydroquinone or benzoquinone or the mixture of said two inhibitors.