Chemistry of hydrocarbon compounds – Alicyclic compound synthesis – Polycyclic product
Reexamination Certificate
2001-07-05
2002-08-27
Killos, Paul J. (Department: 1625)
Chemistry of hydrocarbon compounds
Alicyclic compound synthesis
Polycyclic product
C585S361000, C585S362000, C585S350000
Reexamination Certificate
active
06441259
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the continuous preparation of tetracyclododecenes, more particularly, the invention relates to a process for preparing tetracyclododecenes (may be abbreviated hereafter as TCD), which can be a raw material of cycloolefin (co)polymers possessing excellent characters concerning their optical property, high transparency, heat resistance, and oil absorbency, from an inexpensive raw material of crude dicyclopentadiene (DCPD) in a stable, continuous, and longstanding process.
BACKGROUND ART
Cycloolefin (co)polymers are the focus of industrial attention as polymers that possess excellent characters concerning their optical property, high transparency, heat resistance, and oil absorbency. Cycloolefins represented by cyclohexene, dicyclopentadiene (may be abbreviated hereafter as DCPD), norbornenes, and tetracyclododecenes are a useful raw material for the polymer. These cycloolefins are generally prepared using organometallic complex catalysts. The polymerization method is roughly classified into two: one is the single polymerization of cycloolefins polymerized at their olefinic site or the copolymerization with lower alpha-olefins using Ziegler catalysts or metallocene catalysts. The other is known as the metathesis polymerization that employs the carbene-type catalysts.
With regard to the preparative method of TCD, a typical method is mixing cyclopentadiene (may be called CPD hereafter), dicyclopendtadiene (may be called DCPD hereafter), or a mixture thereof, with 2-norbornenes and ethylene, in a heated condition for the Diels-Alder reaction. This yields a reaction mixture containing tetracyclododecenes and 2-norbornenes. The process of recovery and circulation of norbornenes from the reaction mixture follows. A method of preparing tetracyclododecenes accompanied with the processes of recovery and circulative re-use of the generated norbornenes is reported, for example, in Japan Open H06-9437. This patent proposes a use of DCPD of high purity as a raw material, because industrially available crude DCPD contains impurities such as propenylnorbornene, isopropenylnorbornene, vinylnorbornene, methylbicyclononadiene, or methyldicyclopentadiene. In said process, the reaction mixture discharged from a reactor after the reaction is cooled, depressurized, and treated for separation. The low boiling component in the reaction mixture such ethylene is removed in said process. However, the raw material DCPD of high purity mentioned in the above patent is naturally associated with the high cost for the raw material. Even in the use of highly purified DCPD, a removing process of the low-boiling component is required for the effective use of unreacted compounds. This also leads to the high cost for the raw materials, therefore, rarely adopted in the industrial production.
It is thus concluded that the use of inexpensive crude DCPD as a raw material, and the recovery and circulative re-use of the unreacted olefin leads to an inexpensive production method of TCD, and thus is preferred. However, impurities in the crude DCPD cause newly generation of low-molecular compounds such as isoprene, piperylene, and 1-methyl-2-norbornene. They may contaminate the recovered and circulated raw materials, and prevent a stable production of TCD. Besides, the present inventors discovered that the by-produced high boiling compounds might degrade the purity of the final product TCD. It is also worried that the generated isoprene, piperylene, and 1-methyl-2-norbornene may be accumulated in the circulating system and, in extreme cases, may cause inability to continue the operation, as they are estimated to come from the crude DCPD, which is continuously fed into the reaction system. The present invention proposes a production method of tetracyclododecenes using inexpensive crude DCPD as a raw material in a stable and continuous process.
DISCLOSURE OF THE INVENTION
The first item of the present invention relates to a continuous method for the production of tetracyclododecenes shown by the general formula (3), characterized by feeding continuously an olefin shown by the general formula (1), cyclopentadiene and/or dicyclopentadiene, and 2-norbornenes shown by the general formula (2), into a reaction vessel in heated state for the reaction, wherein at least a part of norbornenes and dicyclopentadiene contained in the reaction mixture coming from the reactor are circulated to said reactor, and relates to a continuous preparation of tetracyclododecenes characterized by maintaining one, two, or three compounds selected from the group comprising isoprene, piperylene, and 1-methyl-2-norbornene existent in the raw material introduced into the reactor within the range specified below
Isoprene: 1-10,000 ppm(wt) against the sum of cyclopentadiene and dicyclopentadiene.
Piperylene: 1-10,000 ppm(wt) against the sum of cyclopentadiene and dicyclopentadiene. 1-Methyl-2-norbornenes shown by the general formula (4): 1-70,000 ppm(wt) against the sum of cyclopentadiene and dicyclopentadiene.
(R1 and R2 in these formulae are identical or different functional groups, and are a hydrogen atom, a methyl group, or an ethyl group).
The second item of the invention relates to a continuous production method of tetracyclododecenes shown by the general formula (3), characterized by inclusion of the following processes of 1 to 5, wherein the contents for one, two, or three compounds selected from the group comprising isoprene, piperylene, and 1-methyl-2-norbornene existent in the raw material introduced into the reactor are maintained within the range specified belolow.
Isoprene: 1-10,000 ppm(wt) against the sum of cyclopentadiene and dicyclopentadiene.
Piperylene: 1-10,000 ppm(wt) against the sum of cyclopentadiene and dicyclopentadiene.
1-Methyl-2-norbornenes shown by the general formula (4): 1-70,000 ppm(wt) against the sum of cyclopentadiene and dicyclopentadiene.
(where R1 and R2 in these formulae are identical or different functional groups, and are a hydrogen atom, a methyl group, or an ethyl group).
1) A process of feeding an olefin shown by the general formula (1), cyclopentadiene and/or dicyclopentadiene, and norbornenes shown by the general formula (2) into a reaction vessel continuously for the reaction (where R1 and R2 in these formulae are identical or different functional groups, and are a hydrogen atom, a methyl group, or an ethyl group).
2) A process of separating an olefin, cyclopentadiene and/or dicyclopentadiene, and norbornenes from the reaction mixture by distillation.
3) A process of circulating at least a part of an olefin, cyclopentadiene, and norbornenes respectively separated in said process 2 to the above reaction vessel.
4) A process of separating tetracyclododecenes from the reaction mixture by distillation succeeding said process 2.
5) A process of isolating tetracyclododecenes from the reaction mixture by distillation succeeding said process 4.
The third item of the invention relates to a continuous production of tetracyclododecenes described in the first item and the second item of the present invention, characterized by extracting dicyclopentadiene from the top of a distillation tower at a condition of the temperature and pressure of the distillation tower at the top in 50-120 degrees centigrade and less than 30 KPa, and the temperature and pressure at the bottom in 80-200 degrees and less than 80 KPa.
The fourth item of the invention relates to a continuous production of tetracyclododecenes described in the first item and the second item of the present invention, characterized by feeding an olefin, crude cyclopentadiene and/or cyclopentadiene, and norbornenes into a reaction vessel in heated sate for the reaction, at a condition of the reaction temperature in 100-400 degrees, the reaction pressure in 0.540 MPa, the residence time in 0.1-360 minutes, and in a molar ratio of dicyclopentadiene/olefin
orbornenes=1/(0.1-50)/(1-50), wherein 2 moles of cyclopentadiene is reduced to 1 mole of dicyclopentadiene.
According to the production methods
Aida Fuyuki
Matsumura Yasuo
Suzuki Takashi
Killos Paul J.
Nippon Petrochemicals Co. Ltd.
Reyes Hector
Weingarten Schurgin, Gagnebin & Lebovici LLP
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