JPH0617326B2 - Method for partial hydrogenation of conjugated dienes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a raw material of a useful polymer, and is a partial hydrogen of a conjugated diene for producing an olefinic compound which is a raw material for various organic phoine derivatives. It relates to the method of conversion.

[Conventional technology]

Various methods of hydrogenating olefins having a plurality of double bonds, that is, polyenes are known, but generally, complete hydrogenation of all double bonds and partial hydrogenation of double bonds at unspecified positions ( For example, it is known that non-selective partial hydrogenation from diene to monoene) and regioselective partial hydrogenation (selectively hydrogenating only double bonds at specific positions) become difficult in this order.

Among the above-mentioned regioselective partial hydrogenation, in general, thermodynamically more stable internal olefins are generated, partial hydrogenation, partial hydrogenation of terminal double bonds, double bonds with fewer substituents. It is known that the degree of difficulty increases in the order of partial hydrogenation of, followed by partial hydrogenation of a double bond having more substituents.

Conventionally, an example of partial hydrogenation of isoprene is known as an example of the partial hydrogenation reaction corresponding to the above. Isoprene and partially hydrogenated 3-methylbutene as relatively good selectivity resulting Example -1, _{^{(b) Co (CN) ▲ 3- 5}} ▼ method according catalyst (ORa between et al, B
all. Chem. Soc. Jpn, 45 , 2723
(1972)), _{(ii) CoBr (PPh 3) 3 -BF} 3 · OEt 2 method by the catalyst (Mizorogi et, Chem.Lett., 847
(1976)), and _{(c) PdCl 2 (PPh 3) 2} -SnCl method according ₂ catalyst (Itaya et al., Ind.Eng.Chem.Prod.
Res. Dev. 11 , No. 2, 146 (197)
2)), etc. are known.

[Problems to be solved by the invention]

However, among these, the methods of (a) and (c) do not have sufficiently high selectivity for 3-methylbutene-1, and the method of (b) has insufficient reaction rate and catalytic activity. It is not enough to use.

On the other hand, there is a method of partially hydrogenating isoprene in the presence of a catalyst composed of a cobalt compound-phosphorus compound-organoaluminum compound (Japanese Patent Publication No. 45-22322), but the production ratio of 3-methylbutene-1 is at most 15%. is there.

Moreover, even in a reaction system having a high selectivity for 3-methylbutene-1 among these, the isomerization reaction of the produced 3-methylbutene-1 abruptly occurs when the conversion of isoprene becomes high, and as a result, the main component is It had the drawback of becoming 2-methylbutene-2.

Moreover, for chain conjugated dienes other than isoprene and having different numbers of substituents in the two conjugated double bonds, the double bond that is substituted more than the other two conjugated double bonds is selectively selected. Little is known about how it can be hydrogenated.

[Means for solving problems]

In consideration of the above facts, the present inventors have considered that among polyenes, regarding chain conjugated dienes in which the number of substituents in two conjugated double bonds is different from each other, The present invention has been achieved as a result of extensive studies to find out a catalyst system and reaction conditions capable of selectively partially hydrogenating only double bonds that are more substituted.

That is, the present invention provides chain conjugated dienes (excluding isoprene) in which two conjugated double bonds have different numbers of substituents in the presence of a catalyst composed of a cobalt compound, an organic phosphine compound and an aluminum compound. Is hydrogenated at a temperature of 50 ° C. or lower to obtain a partial hydride in which a double bond, which is more substituted among the two conjugated double bonds, is selectively hydrogenated. In the presence of a catalyst comprising a cobalt compound, an organic phosphine compound, an aluminum compound and a boron halide compound and / or a protic acid having a pKa of 1 or less,
Chain conjugated dienes (excluding isoprene) having different substitution numbers in two conjugated double bonds are hydrogenated at a temperature of 50 ° C. or lower, and more of the two conjugated double bonds are substituted. The present invention is a method for partial hydrogenation of conjugated dienes, characterized in that a partially hydrogenated compound having a selectively hydrogenated double bond is obtained.

Hereinafter, the present invention will be described in more detail.

In the process of the invention, a catalyst system consisting of a cobalt compound, an organic phosphine compound and an aluminum compound is used.

As the cobalt compound, cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt acetate, cobalt formate, cobalt naphthenate, cobalt oleate,
Salts of cobalt octoate, cobalt cyanide, cobalt fluoride, cobalt bromide, cobalt iodide, etc .; chelate compounds of bis (acetylacetonato) cobalt, tris (acetylacetonato) cobalt, etc .; chlorotris (triphenylphosphine) Examples thereof include organic phosphorus compound complexes such as cobalt, bromotris (triphenylphosphine) cobalt, dichlorobis (triphenylphosphine) cobalt, and dibromobis (triphenylphosphine) cobalt.

Examples of the organic phosphine compound include triphenylphosphine, tris (p-methoxyphenyl) phosphine, tris (o-methoxyphenyl) phosphine, tris (p-trimethylsilylphenyl) phosphine, tri-p-tolylphosphine. And triarylphosphines such as tri-o-tolylphosphine; tri-n-butylphosphine, tri-n-propylphosphine, tri-iso
-Trialkylphosphines such as propylphosphine; triaralkylphosphines such as tribenzylphosphine;
Diphenyl-n-propylphosphine, diphenyl-i
Mixed alkylaryl phosphines such as so-propylphosphine, 1-diphenylphosphino-2-trimethylsilylethane, 1,2-bis (diphenylphosphino) ethane; polymer phosphines such as crosslinked oligomers of triphenylphosphine Etc.

Further, as the aluminum compound, trimethyl aluminum, triethyl aluminum, and tree iso-
Butyl aluminum, tri-n-butyl aluminum,
Tree n-propyl aluminum, tree n-hexyl aluminum, diethyl aluminum hydride, di-i
So-butyl aluminum hydride, diethyl aluminum chloride, di-iso-butyl aluminum chloride, diethyl aluminum bromide, ethyl aluminum dichloride, iso-butyl aluminum dichloride, ethyl aluminum dibromide, ethyl aluminum sesquichloride, iso-butyl aluminum sesquichloride, ethyl Examples include organic aluminum compounds such as aluminum sesquibromide; inorganic aluminum compounds such as aluminum chloride and aluminum bromide.

As the aluminum compound, it is preferable to combine the above-mentioned organic aluminum compound and the inorganic aluminum compound, or to use a plurality of organic aluminum compounds in combination. Further, it is more preferable to use an aluminum compound containing a halogen atom, that is, an organic aluminum compound or an inorganic aluminum compound containing a halogen atom, and an organic aluminum compound containing no halogen atom in combination.

In the present invention, it is effective to further use a boron halide compound and / or a protonic acid having a pKa of 1 or less as a catalyst component.

Examples of the boron halide compound include boron trifluoride,
Boron trichloride, boron tribromide, hydrofluoric boron trifluoride etherate _(BF 3 · _OEt 2), three Hutu boron, include two methanol product _(BF 3 · _2CH 3 OH) and the like.

Further, as the proton acid having a pKa of 1 or less, inorganic protonic acids such as sulfuric acid, hydrochloric acid, hydrobromic acid, nitric acid, phosphoric acid, perchloric acid, tetrafluoroboric acid and thiocyanic acid; trifluoroacetic acid, trichloroacetic acid, trichloromethane Organic protic acids such as sulfonic acid, trifluoromethanesulfonic acid, and p-toluenesulfonic acid can be used.

Among the above, the organic protonic acid is more preferably used.

The cobalt compound is usually 1 to 0.00001 mol as a cobalt atom with respect to 1 mol of the raw material conjugated diene,
Preferably, it is added in the range of 0.1 to 0.0001 mol.

The organic phosphine compound is added in a range of usually 0.1 mol or more, preferably 1 to 1000 mol, more preferably 1 to 100 mol, particularly preferably 1 to 20 mol as a phosphorus atom with respect to 1 mol of the cobalt atom in the cobalt compound. It

The aluminum compound is added in an amount of usually 1 to 100 mol, preferably 2 to 20 mol as an aluminum atom with respect to 1 mol of cobalt atom in the cobalt compound.

Furthermore, when a boron halide compound is used, it is usually 1 to 1 mol with respect to 1 mol of the cobalt atom in the cobalt compound.
It is added in an amount of 100 mol, preferably 1 to 10 mol. When a protonic acid having a pKa of 1 or less is used, it is usually added in an amount of 1 to 100 mol, preferably 1 to 10 mol, per 1 mol of cobalt atom in the cobalt compound.

In the present invention, chain conjugated dienes (excluding isoprene) having different numbers of substituents in two conjugated double bonds are used as a reaction raw material, and more than two conjugated double bonds are substituted. It is intended to selectively hydrogenate only the double bonds that are present.

Here, "chain-like" conjugated dienes refer to conjugated dienes in which at least one double bond of two conjugated double bonds is in a chain portion. For example, if one double bond is in a reduced portion and the other is in a chain portion, it is included.

The type of double bond substituent in the conjugated dienes is not particularly limited, but is preferably an alkyl group.

Specifically, 1-vinylcyclohexene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3
-Hexadiene, 5-methyl-1,3,6-heptatriene, myrcene and the like.

When these exemplified conjugated dienes are hydrogenated according to the method of the present invention, as shown in Table 1, a double bond at a specific position, that is, a divalent bond which is more substituted of two conjugated double bonds. Heavy bonds are selectively partially hydrogenated.

As the reaction temperature, a temperature of 50 ° C. or lower is adopted. 5
At temperatures higher than 0 ° C, the production ratio of isomers other than the target product increases. The reaction temperature is preferably −20 ° C. to 50 ° C.,
More preferably, it is in the range of -5 ° C to 45 ° C.

The reaction pressure is usually from normal pressure to 100 kg / cm ² .

The reaction is usually performed in the presence of a solvent. As a solvent,
Any solvent inert to the reaction may be used, and for example, aromatic hydrocarbons such as toluene and halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, trichlorobenzene, and bromobenzene can be used.

The reaction can be carried out in a batch system, a semi-continuous system, or a continuous system. The reaction product can be separated by a usual separation method, for example, distillation, extraction, adsorption and the like. Especially when separated by distillation, the distillation residue can be recycled as a catalyst liquid.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded.

The reaction rate and production rate were calculated according to the following formulas.

Example 1 A flask having a volume of 100 ml was charged with 59 mg (0.2 mmol) of cobalt (II) acetylacetonate dihydrate and 157 mg (0.6 mmol) of triphenylphosphine, and the system was thoroughly replaced with nitrogen. Chlorbenzene 2 as solvent
0 ml was added. To a suspension of chlorobenzene, 0.6 ml of 10.0 wt% toluene solution of triethylaluminum
(0.46 mmol) was added dropwise with stirring under ice cooling. Further, 0.96 ml (0.34 mmol) of a 10.0 wt% toluene solution of ethylaluminum sesquichloride was added dropwise, and finally 0.39 ml (3.0 mmol) of 1-vinylcyclohexene.
l) was added and the inside of the system was replaced with hydrogen, and then hydrogen was introduced at normal pressure while vigorously stirring under ice cooling. After starting the introduction, hydrogen absorption started and after reacting for 20 minutes, the reaction solution was analyzed by gas chromatography, and the following results were obtained.

1-Vinylcyclohexene reaction rate 80% Vinylcyclohexane production rate 90% 1-Ethylcyclohexene 〃 10% Example-2 0.51 myrcene instead of 1-vinylcyclohexene
20 ml of dichlorobenzene as the solvent using ml (3.0 mmol)
The reaction was performed in the same manner as in Example 1 except that 1 was used, and 8 minutes after the start of the reaction, the reaction solution was analyzed by gas chromatography, and the following results were obtained.

Myrcene reaction rate 90% 3,7-Dimethyl-octa-1,6-diene production rate 66% 3,7-Dimethyl-trans octa-2,6-diene 〃 13% 3,7-Dimethyl-cis-octa-2,6- Jien
〃 21% Example-3 38 mg (0.28 mmol) of aluminum chloride was used in place of the toluene solution of ethylaluminum sesquichloride, and myrcene was used in place of 1-vinylcyclohexene.
The reaction was carried out in the same manner as in Example 1 except that 85 ml (5.0 mmol) was used and 20 ml of trichlorobenzene was used as a solvent, and the reaction solution was analyzed by gas chromatography 20 minutes after the start of the reaction. Obtained.

Myrcene Reaction rate 90% 3,7-Dimethyl-octa-1,6-diene Production ratio 59% 3,7-Dimethyl-trans octa-2,6-diene 〃 27% 3,7-Dimethyl-cis-octa-2,6- Jien
Production ratio 14% Example-4 trans-1, instead of 1-vinylcyclohexene
The reaction was carried out in the same manner as in Example 1 except that 0.3 ml (3.0 mmol) of 3-pentadiene was used to start the reaction 1.
After 1 minute, the reaction solution was analyzed by gas chromatography, and the following results were obtained.

trans-1,3-pentadiene Reaction rate 92% 1-Pentene production ratio 64% trans-2-Pentene 〃 27% cis-2-Pentene 〃 9% [Effect of the invention] The method of the present invention is relatively easy to obtain. The method of the present invention has an extremely high industrial value because it is possible to selectively hydrogenate such conjugated dienes to selectively produce olefinic compounds that are special and difficult to synthesize.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B01J 31/24 X 7821-4G C07B 61/00 300

Claims (2)

[Claims] 1. A catalyst comprising a cobalt compound, an organic phosphine compound and an aluminum compound,
50 chain conjugated dienes (excluding isoprene) having mutually different numbers of substituents in two conjugated double bonds are used.
Part of conjugated dienes, which is characterized in that it is hydrogenated at a temperature of ℃ or less to obtain a partial hydride in which the more substituted double bond of the two conjugated double bonds is selectively hydrogenated. Hydrogenation method. 2. In the presence of a catalyst comprising a cobalt compound, an organic phosphine compound, an aluminum compound and a boron halide compound and / or a protonic acid having a pKa of 1 or less, the number of substituents on two conjugated double bonds is mutually different. Different chain conjugated dienes (excluding isoprene) are hydrogenated at a temperature of 50 ° C. or lower to carry out the above-mentioned conjugation 2
A method for partial hydrogenation of conjugated dienes, which comprises obtaining a partial hydride in which a double bond in which more of the double bonds is substituted is selectively hydrogenated.