Chemistry of hydrocarbon compounds – Aromatic compound synthesis – Having alkenyl moiety – e.g. – styrene – etc.
Reexamination Certificate
2000-04-15
2002-04-30
Dang, Thuan D. (Department: 1764)
Chemistry of hydrocarbon compounds
Aromatic compound synthesis
Having alkenyl moiety, e.g., styrene, etc.
C585S319000, C585S320000, C585S360000, C585S379000, C585S441000, C585S444000, C585S445000, C585S315000, C585S321000
Reexamination Certificate
active
06380450
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel process for producing indene, which is industrially useful as a raw material for producing transparent and highly heat-resistant resin or as a raw material for ligands of single site catalyst for use in the polymerization to prepare polyolefin.
BACKGROUND ART
Various methods for producing indene have hitherto been proposed.
A method of recovering indene from coal tar fraction is known. The coal tar fraction, however, contains various impurities such as benzonitrile and benzofuran. By means of recovery by distillation, it is difficult to obtain highly pure indene by separating benzonitrile, which has a boiling point close to that of indene. It is also proposed to separate indene by causing benzonitrile to react in coal tar fraction. This method, however, is economically unfavorable because of the increase in production steps.
Tetrahydroindene (hereinafter referred to as “THI”) is produced as a by-product in a large quantity, for example, in various kinds of Diels-Alder reaction in chemical industry. Even though its effective uses have been desired, it is rarely used in practice.
Among few uses of THI, there is a proposed method to obtain indene by dehydrogenating THI in the presence of cobalt-molybdenum oxide catalyst as disclosed in U.S. Pat. No. 4,291,181. This method is considered to be suitable for the effective uses of THI, because obtained indene is a useful material in various utilities, in addition, inexpensive metallic catalyst is used and the reaction in itself is dehydrogenation that can be carried out without difficulty.
Although this method has an advantage that high purity indene is obtained and the degree of conversion of THI is high, it has a defect that the yield is low with the cobalt-molybdenum oxide catalyst and further, the deterioration in catalytic activity is conspicuous.
As a result of intensive investigation done by inventors of the present invention concerning the causes of the above disadvantage, it was found out that, under dehydrogenation conditions of THI in which indene is formed in high proportion, THI easily decomposes into cyclopentadiene (hereinafter referred to as “CPD”) and 1,3-butadiene (hereinafter simply referred to as “butadiene”) due to reverse Diels-Alder reaction of the raw material THI itself, and as a result, the yield of indene is lowered, and further that catalytic activity is lowered due to the coking caused by formed indene.
In view of these circumstances, it is an object of the present invention to provide a process to produce indene in high yield at low cost using THI as a raw material and to suppress the deterioration of catalytic activity.
DISCLOSURE OF INVENTION
A first aspect of the present invention relates to a process for producing indene and/or indane in high yield with less degree of deterioration in catalytic activity, which comprises the step of dehydrogenating tetrahydroindene in vapor phase in the presence of a metallic dehydrogenation catalyst.
A second aspect of the present invention relates to a process for producing indene as described in the first aspect of the invention, in which the dehydrogenation is carried out at temperatures of 100° C. or higher using a solid catalyst containing oxides of nickel and molybdenum as the metallic dehydrogenation catalyst.
A third aspect of the present invention relates to a process for producing indene as described in the second aspect of the invention, in which the dehydrogenation is carried out at temperatures in the range of 420° C. to 530° C.
A fourth aspect of the present invention relates to a process for producing indene as described in the second aspect of the invention, in which the dehydrogenation is carried out in the range of a pressure below atmospheric to 10 kg/cm
2
.
A fifth aspect of the present invention relates to a process for producing indene as described in the first aspect of the invention, which comprises the following first step and second step.
(First Step) A process for producing a reaction product containing mainly indane while suppressing the formation of indene by dehydrogenating tetrahydroindene in vapor phase in the presence of metallic dehydrogenation catalyst, and
(Second Step) a process for producing indene by dehydrogenating the reaction product obtained in the first step in vapor phase in the presence of metallic dehydrogenation catalyst.
A sixth aspect of the present invention relates to a process for producing indene as described in the fifth aspect of the invention, in which the content of indane of reaction product obtained in the first step is 70% by weight or more.
A seventh aspect of the present invention relates to a process for producing indene as described in the fifth aspect of the invention, in which the content of indene of reaction product obtained in the first step is 10% by weight or less.
An eighth aspect of the present invention relates to a process for producing indene as described in the fifth aspect of the invention, in which the metallic catalyst used in the first step is metallic oxide catalyst containing molybdenum oxide.
A ninth aspect of the present invention relates to a process for producing indene as described in the eighth aspect of the invention, in which the metallic dehydrogenation catalyst used in the first step is metallic oxide catalyst containing oxides of nickel and molybdenum or metallic oxide catalyst containing oxides of cobalt and molybdenum.
A tenth aspect of the present invention relates to a process for producing indene as described in the fifth aspect of the invention, in which the metallic dehydrogenation catalyst used in the second step is metallic oxide catalyst containing oxide of at least one metal selected from the group consisting of nickel, molybdenum, cobalt and chromium.
An eleventh aspect of the present invention relates to a process for producing indene as described in the tenth aspect of the invention, in which the metallic dehydrogenation catalyst used in the second step is catalyst containing oxides of nickel and molybdenum or oxides of cobalt and molybdenum.
A twelfth aspect of the present invention relates to a process for producing indene as described in the fifth aspect of the invention, in which the metallic dehydrogenation catalyst used in the second step is catalyst containing ruthenium.
The present invention will be described in more detail.
THI used in the present invention may be anyone that is obtained through any method. For example, it can be synthesized by Diels-Alder reaction of butadiene with dicyclopentadiene (hereinafter referred to as “DCPD”) or CPD. This Diels-Alder reaction can proceed by heating 1 mol of butadiene and ½ mol of DCPD or 1 mol of CPD. Although the reaction can be promoted by using an acid or other catalyst, heating is usually sufficient. The reaction temperature is in the range of 70 to 270° C. In the recovered fractions, impurities having boiling points higher than that of THI such as DCPD, methyl tetrahydroindene, or norbornene-type olefin of ethylidene norbornene, or Diels-Alder adduct of DCPD and CPD, are sometimes contained as well as THI.
As described above, by-products formed in a variety of industrial Diels-Alder reaction can also be used as raw material of THI for the present invention besides the one obtained by a process to produce THI itself.
For example, EBH (5-ethylidene-2-norbornene) is produced in a large quantity as a third monomer for producing EPDM (ethylene-propylene-diene ternary copolymer), while its intermediate product of vinyl norbornene (5-vinyl-2-norbornene) is synthesized under conditions similar to those of the above by the Diels-Alder reaction of butadiene with DCPD or CPD. THI is contained in the residue of its crude reaction product after the recovery of vinyl norbornene by distillation.
Also in this case, the above residue sometimes contains impurities having boiling points higher than that of THI such as DCPD, methyl tetrahydroindene, norbornene-type olefin of ethylidene norbornene, and adducts of Diels-Alder reaction of DCPD and CPD, besides TH
Dang Thuan D.
Hollander Law Firm, P.L.C.
Nippon Petrochemicals Company Limited
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