JPH0617322B2 - Method for producing 3-methylbutene-1 - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing 3-methylbutene-1 which is a raw material of a useful polymer.

[Conventional technology]

Conventionally, it is known that 3-methylbutene-1 is produced by partial hydrogenation of isoprene. However, when isoprene is catalytically hydrogenated, in most cases, paraffin (2 -Methylbutane). Even when partial hydrogenation of hydrogenating only one double bond was successful, the main component was hydrogenated 2-methylbutene-2, which is a 1,4-adduct, or a double bond with less steric hindrance. 2-
Methylbutene-1 and the desired 3-methylbutene-1
The generation ratio of is very small.

The relatively good selectivity resulting example partially hydrogenated by 3-methylbutene-1 of isoprene, (1) Co (CN) ▲ 3- 5 ▼ method according catalyst (ORa between et, Bull.Chem.Soc. Jpn, 45 272
_{3 (1972)), (2} ) CoBr (pph 3,) 3 -BF 3 · OEt 2 method by the catalyst (Mizorogi et, Chem.Lett., 84
7 (1976)), and _{(3) PdCl 2 (PPh 3} ) 2 -SnCl 2 catalyst method according (Itaya et al., Ind.Eng.Chem.Pro
d. Res. Dev. 11 , no. 2,146 (197)
2)) etc. are known.

[Problems to be solved by the invention]

However, among these, the methods (1) and (3) above do not have sufficiently high selectivity for 3-methylbutene-1, and the method (2) above does not have sufficient reaction rate and catalytic activity, so that it is industrially difficult. It is not enough to use.

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

[Means for solving problems]

The present inventors arrived at the present invention as a result of extensive studies to find a catalyst system and reaction conditions for producing 3-methylbutene-1 at a high selectivity and a high reaction rate by the partial hydrogenation reaction of isoprene. Is.

That is, the present invention provides a method for producing 3-methylbutene-1 by partial hydrogenation of isoprene, wherein (1) a cobalt compound, (2) an organic phosphine compound, (3) an organic aluminum compound and (4) a proton having a pKa of 1 or less. A method for producing 3-methylbutene-1 is characterized in that hydrogenation is carried out in the presence of a catalyst composed of an acid.

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

In the method of the present invention, a catalyst comprising a cobalt compound, an organic phosphine compound, an organic aluminum compound and a protonic acid having a pKa of 1 or less is used.

As the cobalt compound, cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt acetate, cobalt formate, cobalt naphthenate, cobalt oleate,
Salts such as cobalt octylate, cobalt cyanide, cobalt fluoride, cobalt bromide and cobalt iodide; chelate compounds such as bis (acetylacetonato) cobalt and tris (acetylacetonato) cobalt; chlorotris (triphenylphosphine) Examples thereof include organic phosphorus-cobalt 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
Polymers such as cross-linked oligomers of mixed alkylarylphosphines such as so-propylphosphine, 1-diphenylphosphine-2-trimethylsilylethane, and 1,2-bis (diphenylphosphino) ethane; triphenylphosphine; Examples thereof include phosphine.

Further, as the organoaluminum compound, trimethylaluminum, triethylaluminum, tri-is
o-butyl aluminum, tri-n-butyl aluminum, tri-n-propyl aluminum, tri-n-hexyl aluminum, diethyl aluminum hydride, di-iso-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 aluminum sesquibromide and the like can be mentioned.

Furthermore, as the above-mentioned protic acid having a pKa of 1 or less, inorganic protic acids such as sulfuric acid, hydrochloric acid, hydrobromic acid, nitric acid, phosphoric acid, perchloric acid, tetrafluoroboric acid and thiocyanic acid;
Organic protic acids such as trifluoroacetic acid, trichloroacetic acid, trichloromethanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid and the like can be mentioned. Among the above, the organic protonic acid is more preferably used.

The cobalt compound is 1 mol of raw material isoprene,
The amount of cobalt atom added is usually 1 to 0.00001 mol, preferably 0.1 to 0.0001 mol.
In addition, the organic phosphine compound and the organic aluminum compound are usually 1 to 1 as a phosphorus atom and an aluminum atom with respect to 1 mol of cobalt in the cobalt compound, respectively.
It is added in a range of 00 mol, preferably in a range of 2 to 20 mol. In addition, the above-mentioned protic acid having a pKa of 1 or less is usually 1 to 1 mol of cobalt in the above cobalt compound.
It is added in the range of 100 mol, preferably in the range of 1-10 mol.

As the reaction temperature, a temperature of 50 ° C. or lower is usually adopted. At a temperature higher than 50 ° C., the production ratio of the above-mentioned isomers other than the desired product, 3-methylbutene-1, increases. The reaction temperature is preferably in the range of -20 ° C to 50 ° C, more preferably -5 ° C to 45 ° C.

The reaction pressure is usually from normal pressure to 50 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, for example, toluene,
Chlorobenzene, bromobenzene, etc. can be used.

The reaction can be carried out in a batch system, a semi-continuous system, or a continuous system. The reaction product, that is, the desired 3-methylbutene-1, its isomer, 2-methylbutane, etc., can be separated by a conventional separation method such as distillation, extraction,
It can be separated by adsorption or 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 unless it exceeds the gist.

The abbreviations represent the following, and the reaction rate and production rate were calculated by the following formulas.

IP: isoprene 3MB1: 3-methylbutene-1 2MB1: 2-methylbutene-1 2MB2: 2-methylbutene-2 2MB: 2-methylbutane (*) Reduction products: 3MB1, 2MB1, 2MB2 and 2
MB Example 1 A flask having a volume of 100 ml was charged with 51 mg (0.2 mmol) of cobalt (II) acetylacetonate and 157 mg (0.6 mmol) of triphenylphosphine, and the system was sufficiently replaced with nitrogen, and then chlorobenzene was used as a solvent. 20 ml was added. To a suspension of chlorobenzene, 0.35 ml (0.4 mmol) of a 15 wt% toluene solution of triethylaluminum was added dropwise under ice cooling while stirring. Further trichloroacetic acid 4
9 mg (0.3 mmol) are added and finally isoprene 0.3
After adding ml (3.0 mmol) and replacing the system with hydrogen,
Hydrogen was introduced at normal pressure with vigorous stirring under ice cooling. Hydrogen absorption started after the start of introduction, and after about 4.5 minutes, absorption of a hydrogen amount close to the theoretical amount was observed. Stop the reaction at this point,
When the reaction solution was analyzed by gas chromatography, the following results were obtained.

IP reaction rate 93% 3MB1 generation rate 82% 2MB1 〃 4% 2MB2 〃 14% Comparative Example-1 51 mg (0.2 mmol) of cobalt (II) acetylacetonate and 157 mg (0.6 mmol) of triphenylphosphine in a 100 ml volume flask. ) Was charged and the inside of the system was sufficiently replaced with nitrogen, and then 20 ml of chlorobenzene was added as a solvent. To a suspension of chlorobenzene, 0.7 ml (0.8 mmol) of a 15 wt% toluene solution of triethylaluminum was added dropwise while stirring under ice cooling. Further isoprene 0.3 ml
(3.0 mmol) was added and the system was replaced with hydrogen, and then hydrogen was introduced under atmospheric pressure for 5.5 minutes with vigorous stirring under ice cooling. When the reaction liquid was analyzed by gas chromatography, the following results were obtained.

IP reaction rate 48% 3MB1 production ratio 81% 2MB1 〃 4% 2MB2 production ratio 14% 2MB 〃 0.8% Example-2 Trifluoromethanesulfonic acid 50 mg (0.33 mmol) was used instead of trichloroacetic acid. When the reaction was carried out in the same manner as in Example-1, absorption of a hydrogen amount close to the theoretical amount was observed after about 18 minutes. At this point, the reaction was stopped and the reaction solution was analyzed by gas chromatography, and the following results were obtained.

IP reaction rate 91% 3MB1 generation ratio 89.5% 2MB1 〃 1.4% 2MB2 〃 9% 2MB 〃 0.1% Example-3 Cobalt (II) Instead of acetylacetonate, cobalt (I)
I) Acetylacetonate dihydrate 59 mg (0.2 mmol)
The amount of triphenylphosphine used is 1.31 g
(5.0 mmol), and a solution of triethylaluminum in toluene (10.0 wt%
0.60 ml (0.46 mmol) of a toluene solution was used, and trifluoromethanesulfonic acid 5 was used instead of trichloroacetic acid.
The reaction was carried out in the same manner as in Example 1 except that 0 mg (0.33 mmol) was used. The reaction was stopped when absorption of a hydrogen amount close to the theoretical amount was observed, and the reaction liquid was analyzed by gas chromatography. The following results were obtained.

IP reaction rate 89% 3MB1 production ratio 89.2% 2MB1 〃 1.5% 2MB2 〃 9.2% 2MB 〃 0.1% [Effect of the invention] According to the method of the present invention, isoprene, which is an inexpensive raw material, Since 3-methylbutene-1 can be selectively produced with a high yield and a sufficiently fast reaction rate, the method of the present invention has an extremely high industrial value.

Claims (1)

[Claims] 1. A method for producing 3-methylbutene-1 by partial hydrogenation of isoprene, which comprises (1) a cobalt compound, (2) an organic phosphine compound, (3) an organic aluminum compound, and (4) a protic acid having a pKa of 1 or less. A method for producing 3-methylbutene-1, which comprises hydrogenating in the presence of a catalyst consisting of