JPH0959185A - Production of cyclopentadiene compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely and easily produce the subject compound useful as an additive to synthetic rubber, etc., from an inexpensive raw material by hydrogenating a fulvene compound in the presence of a metallic catalyst. SOLUTION: The objective compound of formula II (e.g. isopropylcyclopentadiene) is produced by hydrogenating (A) a fulvene compound of formula I [R1 and R2 are each H, a 1-8C alkyl, a 4-6C cycloalkyl, a (substituted)phenyl or an aralkyll (e.g. 6,6-dimethylfulvene) in the presence of (B) a metallic catalyst. The component B is preferably composed of a catalyst (e.g. Co/acid clay catalyst) produced by supporting at least one kind of element selected from transition metal elements of the group IVa to the group Ib of the periodic table and metal elements of the group IIb to the group VIb of the periodic table, especially transition metal element such as Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt or Au on a porous carrier.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a cyclopentadiene compound. Cyclopentadiene compounds are used as synthetic rubber additives, resin raw materials and industrial chemicals.
It is also a compound useful as an intermediate for various substances.

[0002]

2. Description of the Related Art Conventionally, the production of cyclopentadiene compounds
As the method, for example, the following methods have been reported. (1) reacting cyclopentadiene with alkali amide
And reacting with an alkyl halide (Monat
sh. ,89, 748 (1958)) and potassium hydroxide
To react with an alkyl halide
(Izv.Vuz.Ser.Khimiyakihi
m. Technologya. ,26(6), 759
(1983)). (2) Cyclopentadiene Grignard reagent with halogen
Method of reacting alkyl halide (Monatsh.,9
0, 568 (1959)) and alkyl tosylate
Method (Japanese Patent Publication No. 51-33901). (3) Method of chemically reducing fulvenes with a metal hydrogen compound
(For example, Liebigs Ann.,589, 91 (19
54) etc.). (4) Making calcium in fulvenes in liquid ammonia
Method (Zh. Org. Khim.,16
(1), 223 (1980)). (5) Cyclopentadienyl sodium and calcium
Method for reacting halogenated aralkyl (J. Organ
etal. Chem. ,113, 225 (197
6). ). (6) Diazotization of cyclopentane and cyclopentadiene
A method of irradiating an object with ultraviolet rays to cause a reaction (Ann.,61
4, 19 (1958)). (7) Cyclopentadiene is used as an aliphatic lower catalyst in the presence of a catalyst.
Method of gas phase reaction with alcohol (Japanese Patent Publication No. 2-9010)
Etc.) or a method of gas phase reaction with ethylene (Chemical Society of Japan)
magazine,3, 375 (1977)).

However, in the conventional production method described above, the method (1) requires that an excess amount of alkali is required and the salt produced as a by-product can be equivalent or more, and the methods (2) and (3) are
The method of (4) and (5) uses an organic metal and a metal hydride compound which are expensive and dangerous when handled.
Alkali metals and alkaline earth metals, which are expensive and dangerous to handle, are used, and the complexity of by-product salts and post-treatments is unavoidable. The methods (6) and (7) are selective due to side reactions. It was not suitable as an industrial production method because of problems such as low yield.

[0004]

Therefore, the present invention solves the problems of the prior art and is an industrial process for producing a cyclopentadiene compound which is inexpensive as a raw material, is safe in handling and does not require complicated post-treatment. To provide.

[0005]

That is, the present invention provides a cyclopentadiene compound represented by the following formula (2) by hydrogenating a fulvene compound represented by the following formula (1) in the presence of a metal catalyst. Manufacturing method.

[0006]

Embedded image

(Wherein R ₁ and R ₂ may be the same or different and are hydrogen or a C _{1 to} C ₈ alkyl group, C ₄ to
The C ₆ cyclic alkyl group, a phenyl group which may have a substituent and an aralkyl group are shown. )

[0008]

Embedded image

(Wherein R ₁ and R ₂ are the same as those in the above formula (1))

The cyclopentadiene compound obtained by the method of the present invention is usually obtained as a 1- or 2-isomer or a mixture thereof.

In the present invention, the above formulas (1) and (2) are used.
In the compound represented by₁, R₂Specifically,
R₁, R₂Both are hydrogen, or methyl, ethyl,
Such as ropyl, butyl, pentyl, hexyl, octyl, etc.
Alkyl group; cyclobutane, cyclopentane, cyclohexyl
Compounds that are cyclic alkyl groups such as xane; R₁, R ₂
One of is hydrogen, or alkyl such as methyl or ethyl
One of the groups may be phenyl or may have a substituent.
A compound which is a phenyl group; R₁, R₂One side is hydrogen, methyl
, Ethyl, propyl, butyl, pentyl, hexyl,
Alkyl group such as octyl, the other is benzyl, phenene
Examples thereof include compounds that are aralkyl groups such as tyl.

In the present invention, the fulvene compound represented by the above formula (1) can be prepared according to, for example, J. Org. Chem. ,
49 , 1849 (1984), and can be easily produced by reacting cyclopentadiene with an aldehyde compound or a ketone compound.

Specific examples of the fulvene compound represented by the above formula (1) include, for example, 6,6-dimethylfulvene, 6-methyl-6-ethylfulvene, 6,6-pentamethylenefulvene, 6-cyclohexylfulvene. 6-
Examples include phenylfulvene.

In the metal catalyst used in the present invention, the metal element is a transition metal element belonging to IVa to Ib and a metal element belonging to IIb to VIb in the periodic table from the 4th period to the 6th period. Of these, transition metal elements preferably belonging to IVa to Ib, particularly preferably VIIIa
To Ia-based transition metals.

Specifically, Ti, V, Cr, Mn, F
e, Co, Ni, Cu, Zr, Nb, Mo, Tc, T
transition metals such as a and W, and Zn, Ga, Ge, and A
Examples thereof include metal elements such as s, Se, Cd, and In, preferably Fe, Co, Cu, Ni, Ru, Rh, and P.
Examples thereof include transition metals such as d, Ag, Re, Os, Ir, Pt and Au.

These metal catalysts are used without supporting one or more of the above transition metal elements or metal elements on a carrier or by supporting them on a carrier. As the carrier, for example, porous carriers such as silica, alumina, magnesia, silica-alumina, titania, carbon, zeolite, diatomaceous earth and acid clay are preferably used.
In addition, one or more non-metal substances may be added as another component to the one or more metal elements used in the metal catalyst.

The metal catalyst of the present invention can be prepared according to a conventional catalyst preparation method. For example, a metal compound containing one or more kinds of metals or one or more kinds of metal elements is supported on a carrier, and then chemically supported. Activated by a conventional method and a hydrogen reduction method. In the present invention, the metal catalyst used is preferably a catalyst in which one or more kinds of metals or metal compounds containing one or more kinds of metal elements are supported on a porous carrier from the viewpoint of selectivity.

The amount of metal supported is determined in consideration of the loss of active metal,
It is usually 50% by weight or less, preferably 30% by weight or less, particularly preferably 10% by weight or less.

In the present invention, the metal catalyst is usually contained in an amount of 50% by weight to the raw material fulvene compound represented by the formula (1).
In the range of 0.01% by weight, preferably 10% by weight to 0.
Used in the range of 01% by weight.

The reaction of the present invention is carried out in a liquid phase or a gas phase without solvent or in the presence of a solvent. The solvent used is not particularly limited as long as it is not a hydrogen reduction solvent,
Among these, especially n-hexane, aliphatic hydrocarbon solvents such as n-heptane, alcohol solvents such as methanol and ethanol, other acetonitrile, water and the like,
These may be used alone or as a mixture.

The hydrogen pressure used in the present invention is not particularly limited, and the conditions of normal pressure to pressurization can be appropriately selected. However, when the reaction is carried out under pressure, if the hydrogen pressure is too high, the product may decompose and the yield may be lowered, or the operability of the reaction may be difficult. Therefore, the hydrogen pressure is generally 300 kg / m ² or less, preferably 100 kg / m ² or less, and particularly preferably 50 kg / m ² or less. The hydrogenation reaction may be a continuous or batch reaction method and can be appropriately selected. In the case of continuous reaction, the flow rate of hydrogen used is not particularly limited as long as there is no problem in the reaction rate in practical use and can be appropriately selected depending on the situation, but generally 1 to 5000 ml / min
/ G, preferably 10 to 1000 ml / min / g.

[0022]

The present invention will be described below in detail with reference to examples.

Example 1 6,6-Dimethylfulvene 1 g, 5% Co / acid clay catalyst 0.1 g, methanol 40 g 200 ml ocre
Put it in a tube and add 150g of hydrogen / nitrogen = 1 mixed gas.
The mixture was charged under pressure of g / m ² and reacted with stirring at 60 ° C. for 5 hours. After the reaction, the pressure was returned to normal pressure to filter the catalyst, and then the solvent was distilled off to obtain 0.46 g of liquid (yield 45%). As a result of the analysis, the liquid was the target product, isopropylcyclopentadiene.

Example 2 Same as Example 1, 6,6-dimethylfulvene 1 g, 10
% Cu / zeolite catalyst 0.1 g and methanol 40 g were put in a 200 ml occlave, and hydrogen / nitrogen = 1
And pressurize it to 100 kg / m ² with the mixed gas of
The reaction was carried out with stirring at 3 ° C for 3 hours. After the reaction, the pressure was returned to normal pressure to filter the catalyst, and then the solvent was distilled off to obtain 0.54 g of liquid (yield 53%). As a result of analysis, the obtained liquid was exactly the same as the substance of Example 1.

Example 3 Same as Example 1, 6,6-dimethylfulvene 1 g, 3%
0.1 g of Pd / carbon catalyst and 40 g of methanol were charged, and the mixture was stirred at room temperature for 2 hours while blowing hydrogen at 50 ml / min. After the reaction, the solvent was distilled off to give a liquid of 0.6
3 g (yield 62%) was obtained. As a result of analysis, the obtained liquid was exactly the same as the substance of Example 1.

Example 4 1,6-Pentamethylenefulvene (1 g), 1% Pd / alumina catalyst (0.2 g), and acetonitrile (40 g) were charged, and hydrogen was blown at a rate of 200 ml / min while heating at 50 ° C. for 2 hours.
Stirred for hours. After the reaction, the catalyst was filtered and the solvent was distilled off to obtain 0.64 g of liquid (yield 63%). As a result of analysis, the above liquid was the target substance cyclohexylcyclopentadiene.

Example 5 6,6-Pentamethylenefulvene (1 g), 5% Ni / acid clay (0.2 g), and acetonitrile (40 g) were added to 200 ml.
Put in a toclave, 50k with mixed gas of hydrogen / nitrogen = 1
The mixture was charged under pressure of g / m ² and stirred at 80 ° C. for 2 hours.
After the reaction, the pressure was returned to normal pressure, the catalyst was filtered, and the solvent was distilled off to obtain 0.56 g of liquid (yield 55%). As a result of analysis, the obtained liquid was the same substance as in Example 4.

Example 6 1 g of 6-methyl-6-ethylfulvene, 0.1 g of 1% Pt / silica catalyst and 40 g of n-heptane were charged, and the mixture was stirred at 100 ° C. for 2 hours while blowing hydrogen at 100 ml / min. After the reaction, the catalyst was filtered and the solvent was distilled off to obtain 0.61 g of liquid (yield 60%). As a result of the analysis, the liquid was the target product isobutylcyclopentadiene.

Example 7 1 g of 6-phenylfulvene, 0.2 g of 1% Rh / silica-alumina catalyst and 40 g of ethanol were mixed, and hydrogen of 20 was added.
While blowing at 0 ml / min, the mixture was stirred at 50 ° C. for 2 hours. After the reaction, the catalyst was filtered and the solvent was distilled off to obtain 0.54 g of liquid (yield 53%). As a result of analysis, the above liquid was the target product, benzylcyclopentadiene.

[0030]

According to the production method of the present invention, a cyclopentadiene compound useful as a synthetic rubber additive, a resin raw material, an industrial chemical, and an intermediate for various substances can be produced safely and easily from an inexpensive raw material. can do.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C07C 5/03 9546-4H C07C 5/03 5/13 9546-4H 5/13 13/28 9546- 4H 13/28 // C07B 61/00 300 C07B 61/00 300

Claims (4)

[Claims] 1. A method for producing a cyclopentadiene compound represented by the following formula (2), which comprises subjecting a fulvene compound represented by the following formula (1) to a hydrogenation reaction in the presence of a metal catalyst. Embedded image (In the formula, R ₁ and R ₂ may be the same or different and are hydrogen or a C _{1 to} C ₈ alkyl group, a C _{4 to} C ₆ cyclic alkyl group, a phenyl group which may have a substituent, An aralkyl group is shown.) (In the formula, R ₁ and R ₂ are the same as the above (1).) 2. The method according to claim 1, wherein the metal catalyst is at least one selected from transition metal elements belonging to IVa to Ib and metal elements belonging to IIb to VIb of the periodic table. 3. The metal catalyst is Fe, Co, Ni, Cu, R.
The method according to claim 1, which is at least one kind of transition metal element selected from u, Rh, Pd, Ag, Os, Ir, Pt, and Au. 4. A catalyst in which at least one selected from transition metal elements belonging to IVa to Ib of the periodic table and metal elements belonging to IIb to VIb is supported on a porous carrier. the method of.