JPS5810528A - Preparation of hexadienes - Google Patents

Abstract

PURPOSE:To obtain the titled compound in high selectivity and in high yield, by using a catalyst prepared by combining a cobalt compound with a diphosphite compound and an organoaluminum compound, reacting ethylene with a 1,3-diene catalytically so that they are codimerized. CONSTITUTION:Ethylene is reacted with a 1,3-diene in a solvent or in the absence of a solvent at room temperature- 120 deg.C under ethylene pressure of 3-50kg/cm<2>G in the presence of a catalyst consisting of a cobalt compound, a diphosphite compound shown by the formulaI(R<1>-R<4> are alkyl, aryl, aralkyl, alkoxy, aryloxt, or halogen; R<5> is alkylene, phenylene, biphenylene, a group shown by the formula II, etc.; with the proviso that R<1> and R<3> may form a bridge of -O-R<6>-O- and R<2> and R<4> may form a bridge of -OR<7>-O-, R<6> and R<7> are shown as for R<5>) and an organoaluminum compound shown by the formula III(R is alkyl, aryl, or aralkyl; X is R or H).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ethylene, butadiene, isoprene, etc.
- A method for producing hexadienes by codimerization with dienes.

As a method for synthesizing hexadienes by reacting ethylene with butadienes, methods using various catalysts have been provided, such as a method using rhodium trichloride as a catalyst (French Patent No. 1319578), rhodium acetyl A method using an organorhodium compound such as acetonate and an alkyl aluminum halide compound (Japanese Patent Publication No. 13378/1978), a method using a catalyst consisting of a complex compound of a nickel compound and a trivalent phosphorus compound and an organoaluminum compound (77 Lance Patent - No. 1388
No. 305) etc. are known. In these methods, the catalyst is extremely expensive, and in addition to hexashun, there are many by-products of octadiene, which is a dimer of 1,3-dienes, and the selectivity of the target hexadiene is low. It had the disadvantage of not being expensive, so I wasn't necessarily satisfied with it.

On the other hand, a method using a catalyst in which a cobalt compound, a phosphorus compound, and an organoaluminum compound are combined has been proposed as a method for producing hexadienes in high yield. For example, Japanese Patent Publication No. 45-7525 describes a method using a cobalt salt, morsphite, and an organoaluminum compound, but in this method, the ethylene pressure during the reaction is as high as several tens of kg/cJ a, and the catalyst It is necessary to increase the concentration, and lowering the catalyst concentration has the disadvantage that the reaction time becomes longer. Also, a method using tertiary diphosphine as a phosphorus compound (Japanese Patent Publication No. 45-9
165 and Japanese Patent Publication No. 47-41321), however, the tertiary diphosphine used in this case is not easy to synthesize and is expensive, so there are problems in industrial use from an economic point of view. be.

The present inventors investigated catalysts for the trimerization reaction between ethylene and 1,3-diene, and found that a catalyst composed of a combination of a cobalt compound, a diphosphite compound, and an organoaluminium compound was effective in the trimerization reaction of 1,3-diene itself. It has been found that it produces almost no by-products, has high selectivity, and has high activity. The present invention is characterized by a diphosphite compound which is one component of the combination catalyst, and by using this diphosphite compound, the problems of the conventional method are solved. This is a method for producing hexadienes, which is characterized in that a catalyst consisting of the following (a), (b), and (c) is used when producing hexadienes by catalytically reacting the following.

(a) Cobalt compound (b) Diphosphite compound represented by the following formula [where R1, R2, R3 and R4 are each independently an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, or a halogen atom; R5 is Al,
kylene group, phenylene group, biphenylene group (m represents 1-2, n represents 1-5).

Also, R' and R3 are of the 10-R6-0- type, R2 and R
4 may form a -0-R7-0- type bridge, in which case R6 and R7 mean the same group as R5. ] (Q) Organoaluminum compound At(
R)X [Here, B is an alkyl group, an aryl group, or an aralkyl group, and X represents R or hydrogen. ].

(1) Cobalt compounds The cobalt compounds used in the present invention include cobalt halides, carboxylates, β-diketone compounds,
Nitrates, sulfates, etc., and halides, carboxylates, and β-diketone compounds are particularly preferred. Examples of halides include cobalt chloride, cobalt fluoride, cobalt bromide,
Examples include cobalt iodide. The carboxylate is an aliphatic carboxylate having 2 to 12 carbon atoms, or an aliphatic carboxylate having 7 to 12 carbon atoms.
]-5, such as cobalt acetate, cobalt propionate, cobalt octenoate, cobalt benzoate, and cobalt naphthenate. β
- What is a diketone compound? Alkadione a having 3 to 12 carbon atoms such as pentane-2,4-dione, hexane-2,4-';on, 1,3-diphenylpropane-1,3-dione, 115-diphenylpene diphenyl alkadiones having 3 to 12 carbon atoms in the alkadione moiety such as 2,4-dione, and 1-phenylbutane-1,3-dione;
It is a cobalt compound in which a monophenyl alkadione, such as l-phenylpentane-1,3-dione, having an alkadione moiety having 3 to 12 carbon atoms is coordinated. When cobalt halides, nitrates, sulfates, etc. are used, they may be anhydrous salts or hydrates.

When using these cobalt compounds, it is preferable to dry them.

(@Diphosphite compound The diphosphite compound used in the present invention is represented by the following formula.

where R1-R4 each independently have a carbon number of 1
~12 alkyl group, aryl group having 6 to 14 carbon atoms, aralkyl group having 7 to 15 carbon atoms, alkoxy group having 1 to 12 carbon atoms, aryloxy group having 6 to 14 carbon atoms, or halogen atom, and R5 is carbon alkylene group of number 2 to 15,
Phenylene group, biphenylene group (t is 1-5, m is 1-
2, n represents 1 to 5). In addition, R1 and R3 are of the -Q -R6-0- type, and R2 and R4 are of the 10-R7 type.
-0- type bridge), in which case R6 and R7 mean the same group as R5.

Examples of such diphosphite compounds include the following.

However, in the above formula, Et represents an ethyl group, Eu represents a butyl group, and ψ represents a phenyl group.

The amount of diphosphite used in the present invention is 6.1 to 10 mol, usually 0.2 to 3 mol, per 1 mol of cobalt compound.

(2) Organoaluminum compound The organoaluminum compound used in the present invention is represented by, where R is a carbon number], an alkyl group having ~12 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group, and
is hydrogen or R. Specific examples include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisobutylaluminum, diisobutylaluminum hydride, trihexylaluminum, and trioctylaluminum, with trialkylaluminum being particularly preferred.

The amount of the organoaluminum compound used in the catalyst of the present invention is 3 to 200 mol, preferably 5 to 50 mol, per 1 mol of the cobalt compound.

The method of the present invention is accomplished by bringing ethylene and 1,3-butadiene into contact with a catalyst comprising a cobalt compound, a diphosphite compound, and an organoaluminum compound in the presence or absence of a solvent.

Solvents used in the present invention include, for example, aliphatic hydrocarbons such as butane, pentane, hexane, octane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, and dichloromethane, dichloroethane, trichloroethane, chlorobenzene, and bromine. These include halogenated hydrocarbons such as benzene.

Ethylene and 1,3-butadiene react stoichiometrically, but these two components do not necessarily have to be present in an equivalent relationship in the reaction system;
It is preferable to use 0.1 to 10 moles of butadiene.

There is no particular restriction on the amount of catalyst used for the starting material consisting of ethylene and 1,3-butadiene, but it is usually 1,3-butadiene.
- A cobalt compound is used in an amount of 0.0001 to 0.1 molar equivalent, preferably 0.0005 to 0.01 molar equivalent, based on the butadiene.

The reaction temperature is 0 to 150°C, preferably room temperature to 120°C.
It is carried out in the range of C.

Further, the method of the present invention can be carried out at normal pressure, but under pressure of ethylene at 2 to 1 OOkg/CdG, especially 3 to 5 okI? /
It is preferable to use cJG.

The hexadienes thus produced can be catalytically decomposed with methanol-hydrochloric acid, etc., and then purified using a medium such as distillation.
Since the hexa)ene can be removed from the reaction system, the catalyst can be used continuously.

The 1,3-dienes that are one of the starting materials of the present invention include l,3-butadiene, isoprene, piperylene,
2-ethyl-1,3-butadiene, 2,3-dimethyl-
1,3-butadiene, 1,3-hexadiene, 4,4-
dimethyl-1,3-butadiene, l,4-dimethyl-1
, 3-butadiene is used.

According to the method of the present invention, as mentioned above, the reaction of only butadiene hardly occurs, so that hexadienes can be obtained with high selectivity even at a high concentration of 1,3-butadiene and low ethylene pressure. can.

The diphosphite used in the catalyst system of the present invention is easy to produce industrially and therefore can be obtained at low cost. In addition, the catalyst of the present invention, which uses diphosphite that has both characteristics, is easy to form a binary coordination like conventionally provided diphosphites, and is electron-withdrawing like monobosphites. It has excellent selectivity and high reaction rate, and 90 to 10'' of the raw material 1,3-diene is converted to hexadiene in a reaction time of 1 to 2 hours. On the other hand, when triphenylphosphite is used as the phosphorus compound, the reaction time is 5 hours to obtain a 96% yield, and with trichlorophosphine, only 42% yield can be obtained after 3 hours of reaction. do not have. In addition, when 1,2-bis(diphenylphosphine/)ethane is used, 4
Yield of 95% in hours.

Next, examples of the present invention will be described.

Example 1 Autoclave with electromagnetic induction stirrer (inner volume 500'
m7) was replaced with nitrogen, and then 150 m of toluene was dehydrated and degassed with 0.7 mmot1 of anhydrous cobalt chloride under a nitrogen gas flow.
1. 1 m□z (100 mj) of isoprene was added.

Then 2Bmmol (3.2g) of ethylaluminum
In this order, it was added and sealed. The temperature was raised to 90°C and the pressure was increased to s kg/c+JG with ethylene. After reacting for 2 hours, a dilute aqueous hydrochloric acid solution was added to decompose the catalyst. The conversion rate of isoprene was 98.6%, and the yield of methylhexadiene (MHD) was 94.5%. Here, the yield is a value determined by the following formula.

Examples 2 to 20 A reaction for producing methylhexadiene was carried out under the same operations and conditions as in Example 1, except that the cobalt compound 2, diphosphite compound, and organoaluminium compound were changed. The results are shown in Table 1 together with the results of Example 1.

Example 21 In Example 1, 1 mol of isoprene was substituted and 1.
The reaction and catalytic decomposition were carried out under the same operation and conditions except that 3-butadiene l moA was used. The conversion rate of butadiene was 98.5%, and the yield of hexadiene based on the raw material butadiene was 96.7%.

Applicant: Mitsubishi Yuka Co., Ltd. Agent: Patent attorney Katsura Atsuta

Claims (1)

[Claims] (1) When producing hexadienes by catalytically reacting ethylene and 1,3-dienes, the following (&)
, (b) and (c). (&) Cobalt compound (b) Diphosphite compound e represented by the following formula [where ul, R2, R3 and R4 are each independently an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, or a halogen atom. Yes R6 represents an alkylene group, a phenylene group, a biphenylene group, m represents 1 to 2, and n represents 1 to 5). Also, R1 and R3 are of the 10-R6-0- type, R2 and R
4 may form a 10-R7-0- type bridge, in which case R6 and R7 mean the same group as R5. ] (c) Organoaluminum compound At(
R)2M [Here, R is an alkyl group, an aryl group, or an aralkyl group, and X represents R or hydrogen. ]