Chemistry of hydrocarbon compounds – Alicyclic compound synthesis – By shift – opening – or removal of shared-carbon ring
Reexamination Certificate
2001-04-02
2003-07-01
Nazario-Gonzalez, Porfirio (Department: 1621)
Chemistry of hydrocarbon compounds
Alicyclic compound synthesis
By shift, opening, or removal of shared-carbon ring
C556S136000, C427S593000
Reexamination Certificate
active
06586648
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing cyclopentadiene or a derivative thereof usable as a raw material of an organic metal compound for use as a source material for CVD and to an apparatus for the process. The present invention also relates to a process for producing an organic metal compound using the cyclopentadiene or derivative thereof produced by the process.
2. Description of the Related Art
Chemical vapor deposition (hereinafter, referred to as “CVD”) can provide a uniform film and is good in step coverage, and therefore recently has been widely applied in a process for producing a circuit board or a thin film electrode for an electronic component for which higher density is required.
The source materials used for CVD are organic metal compounds which have lower melting temperatures and are easier to handle than other metal compounds. Typical organic metal compounds widely applicable as CVD source materials are metallocenes (i.e., biscyclopentadienyl metal complexes) represented by formula (1) and derivative thereof having a functional group (e.g., a hydrocarbon, amino, carboxyl or ether group) introduced to one or both of the hydrogen moieties on the cyclopentadiene rings. In particular, the latter metallocene derivatives have been expected as potential source materials for CVD, because they have high vapor pressures and also have properties suitable as source materials for CVD.
Formula (1)
wherein each of substituents R
1
and R′
1
is a hydrogen atom or at least one of substituents R
1
and R′
1
is a hydrocarbon, amino, carboxyl or ether group; and M represents a metal atom.
The metallocene and derivative thereof have a sandwich structure in which a metal atom is sandwiched between two cyclopentadiene rings. As is apparent from the structural formula above, the metallocene has been produced by reacting cyclopentadiene with a metal compound (e.g., a chloride, a calbonylated compound). The metallocene derivative has been produced by reacting a cyclopentadiene derivative into which a functional group is previously introduced with a metal compound.
On the other hand, cyclopentadiene and a derivative thereof have the property of readily causing dimerization at a temperature around room temperature. Therefore, in general, for the production of a metallocene or a derivative thereof, dimeric dicyclopentadiene or a dimeric dicyclopentadiene derivative is thermally decomposed into monomers and then provided to the reaction for the production of the metallocene or derivative thereof.
SUMMARY OF THE INVENTION
However, the dimers as the raw materials of the cyclopentadiene or derivative thereof may contain an impurity or impurities, although in a small amount. If a dimer of such impurity-containing cyclopentadiene or derivative thereof is thermally decomposed, the resulting cyclopentadiene or cyclopentadiene derivative may also contain an impurity or impurities.
Particularly, a cyclopentadiene derivative has been produced by first reacting cyclopentadiene with metal sodium to produce a cyclopentadiene-type anion and then introducing a functional group to the anion. In this case, cyclopentadiene is usually added in an excess amount in view of the safety during operation. Hence, dimerization between the cyclopentadiene derivative product and the unreacted cyclopentadiene may occur to produce a dimer as an adverse by-product, which may be contained in the cyclopentadiene derivative. Moreover, in this production process, an undesired cyclopentadiene derivative to which a larger number of the functional groups than required are introduced or an unintended functional group is introduced may also be contained. Accordingly, when the reaction product is thermally decomposed, unreacted cyclopentadiene or an unexpected cyclopentadiene derivative may be contained as an impurity in the cyclopentadiene derivative product.
The use of a monomer of such impurity-containing cyclopentadiene or cyclopentadiene derivative may inevitably lead to low purity of the resulting metallocene or metallocene derivative.
A source material for CVD is required to be highly pure for ensuring satisfactory electrical properties as a thin film. Accordingly, when a metallocene or a derivative thereof with low purity is used as the source material, it is required to remove an impurity or impurities. However, once a metallocene or metallocene derivative is formed, such purification is quite difficult because physical properties among the produced metallocene derivatives are similar to each other. For these reasons, it is necessary to provide a cyclopentadiene monomer of high purity for the production of a metallocene of high purity.
Under these situations, the present invention has been developed. Accordingly, the object of the present invention is to provide a process for producing cyclopentadiene or a derivative thereof with high purity for use in the production of a metallocene or metallocene derivative with high purity as a source material of CVD and to provide an apparatus for the process. Another object of the present invention is to provide a process for producing a metallocene or a metallocene derivative using cyclopentadiene or a derivative thereof produced by the process.
In order to solving the problems as mentioned above, the present inventors made studies on the purification of cyclopentadiene or a cyclopentadiene derivative which is a monomer produced after the thermal decomposition of a dimeric form thereof. However, the inventors concluded that the removal of an impurity or impurities in this state is not practical, because the amount of the impurity or impurities contained in the product is very small. Then, the inventors have considered that only a desired monomer could be removed during the thermal decomposition of the dimer so that the production and purification of the monomer can be performed simultaneously and, consequently, monomeric cyclopentadiene or cyclopentadiene derivative of high purity could be produced with good efficiency. This consideration led to the accomplishment of the present invention.
The present invention provides a process for producing cyclopentadiene or a derivative thereof by heating a mixture containing dicyclopentadiene or a derivative thereof represented by formula (2) to produce cyclopentadiene or a derivative thereof represented by formula (3), the process comprising: a first step comprising heating the mixture into vapor; a second step comprising maintaining while heating the vapor at a temperature higher than the boiling point of the desired cyclopentadiene or derivative thereof to thereby condense and remove a high-boiling component(s) and simultaneously collect the residual vapor; and a third step comprising maintaining while heating the collected vapor at a temperature lower than the boiling point of the desired cyclopentadiene or derivative thereof to thereby condense and collect the cyclopentadiene or derivative thereof:
Formula (2)
wherein each substituent group R represents a hydrogen atom or a hydrocarbon, amino, carboxyl or ether group;
Formula (3)
wherein a substituent group R is as defined above.
The present invention is characterized in that two temperature ranges are selected around the boiling point of desired cyclopentadiene or derivative thereof and the vapor of a monomer which is produced by thermal decomposition of a dimeric compound is subjected to two-stage distillation treatment within the two temperature ranges, so that the thermal decomposition of the dimeric compound and the removal of an impurity or impurities from the resulting monomeric products can be achieved simultaneously. That is, in the distillation process under high temperature of step 2 performed after the thermal decomposition of step 1, an impurity or impurities having a boiling point higher than that of the desired cyclopentadiene (herein, also referred to as “high-boiling impurity or impurities”) are heated at a temperature lower than the boiling point of the cyclopentadiene and condensed.
Kitada Katsutsugu
Suzuki Hiroaki
Nazario-Gonzalez Porfirio
Rothwell Figg Ernst & Manbeck
Tanaka Kikinzoku Kogyo K.K.
LandOfFree
Process for producing cyclopentadiene or derivatives thereof... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing cyclopentadiene or derivatives thereof..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing cyclopentadiene or derivatives thereof... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3037846