JPS5918369B2 - Manufacturing method of isoprene trimer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION The present invention relates to a process for producing isoprene trimers using a highly active catalyst with high cyclic trimer selectivity.

Isoprene oligomers are important intermediates for perfumes, pharmaceuticals, and other industrial chemicals, and among these, cyclic trimers are useful as perfume derivatives due to their high aromatic properties.

5 Conventionally, Ti-based and C-based catalysts are used to produce cyclic trimers.
Various methods using r-based and Ni-based complexes have been studied, but the structures of the products are different from each other.

Regarding the cyclic trimer of isoprene, there are positional isomers of the 0 methyl group and trans and cis isomers of the double bond, and they are roughly classified into two groups.

That is, a symmetrical structure [all 1=4 bonds of 1,5,9-trimethylcyclododecatriene (1,5,9), trans, trans, trans form] and an asymmetric '5 structure [1-4 bonds] , 1.6.9 = a mixture of 4-4 bonds, or 1.5.10 = trimethylcyclododecatriene (1.5.9), a mixture of trans, trans, and cis forms]. Of these, trans, '0 trans, and trans isomers (all-trans isomers) with good double bond symmetry are obtained with Ni-based catalysts, while asymmetric trans, trans isomers are obtained with Ti-based and Cr-based catalysts. , a cis-isomer mixture is the product.

In addition, derivatives with excellent aroma properties can be obtained from this all-trans ring trimer with good symmetry (Japanese Patent Application Laid-Open No. 100247-1983).

Therefore, various researches have been carried out to improve the activity and selectivity of Ni-based complex catalysts. Especially Ni
In system complexes, the structure of the reaction product is regulated by the type of ligand added, so the selection of the ligand is important.

For example, a cyclic trimer of butadiene can be obtained with high activity and high selectivity using only a normal zero-valent Ni complex, but with isoprene, the activity is low and the selectivity is poor. The activity is improved and the cyclic dimer becomes the main product (Japanese Patent Publications No. 38-16882, No. 39-14673, No. 39-19156, No. 39-17275, No. 43-22975, No. 48-64049), and when a specific aminophosphine is added as a ligand, a chain trimer becomes the main product (Japanese Patent Publication No. 49-7128). In order to increase the selectivity of the cyclic trimer, phosphites with a specific structure (JP-A-49-56950, JP-A-49-56951), arsenic, antimony compounds (JP-A-50-31138), or phenols (JP-A-5, 1983) are used.
0-93941) is added.

However, in these conventional methods, the isoprene reaction rate is low despite the high catalyst concentration, and increasing the isoprene reaction rate increases the amount of by-products with higher boiling points than the trimer, resulting in a decrease in trimer selectivity. There were problems such as high-boiling by-products adhering to the reactor.

Summary of the Invention As a result of repeated research in order to overcome the above-mentioned difficulties, the present inventors have discovered that this special In order to better demonstrate the performance of the phosphorus compound, it was discovered that when a lower alcohol was used in combination, the selectivity of the cyclic trimer could be improved and the amount of by-products with higher boiling points than the trimer could be suppressed, and the present invention reached.

Therefore, the method for producing an isoprene trimer of the present invention consists of the following (A), (B), (Q and (6)) in the method for producing the trimer by catalytic oligomerization of isoprene. It is characterized by using a catalyst system. (4) Olefin coordination complexes of nickel, 2
(B) An aluminum compound represented by the following general formula (wherein R and R1 are an alkyl group or an aryl group having 1 to 10 carbon atoms, m is an integer of 1 to 3) (0 A reaction product of a phosphite and cyclohexanetriol represented by the following general formula (wherein R2 is an alkyl group having 2 to 6 carbon atoms or an aryl group)
Alcohols having 2 to 6 carbon atoms According to the present invention, the 0R of the phosphite which is the component (C)
The two groups are highly active as a result of the special phosphorus compound transesterified with cyclohexanetriol, which has moderate electron donating properties and moderate steric hindrance, and has unique performance as a ligand. , a catalyst with high selectivity for cyclic trimers is provided.

The trimer fraction obtained by this method has a very high cyclic selectivity and good purity, so there is no need to separate the chain trimers.

Furthermore, the obtained cyclic trimer is rich in all-trans isomers and is extremely useful as a raw material for fragrances, and the present invention is an industrially extremely valuable production method, as there are fewer by-products than the trimer.

Detailed Description of the Invention 1 Catalyst (4) Nickel Compound Nickel compounds are olefin coordination complexes of nickel, salts of divalent organic acids, or divalent chelate salts, examples of which include the following: can give.

Olefin coordination complexes, such as biscyclopentadiene nickel, biscyclooctadiene nickel, bisacrylonitrile nickel, bisacrylonitrile nickel,
Salts of divalent organic acids such as nickel octylate, nickel naphthenate, nickel caprate, nickel stearate, nickel formate, nickel benzoate, nickel octenoate, divalent nickel chelate salts such as nickel acetylacetonate, nickel Acetyl acetate, bissalicylaldehyde nickel, bisorthooxyacetophenone nickel, nickel dibenzoin methane.

Among these nickel compounds, biscyclooctadiene nickel, nickel naphthenate, nickel stearate, nickel acetylacetonate, and nickel acetylacetate are particularly preferred.

(B) Aluminum compound It is expressed by the following general formula.

In the formula, R and R1 are an alkyl group or an aryl group having 1 to 10 carbon atoms, and m is an integer of 1 to 3.

Examples include:

Trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, ethoxydiethylaluminum, ethoxydiisobutylaluminum, triphenylaluminum, trinormalhexylaluminum, phenoxydiethylaluminum, trioctylaluminum, tridecylaluminum.

Among these aluminum compounds, triethylaluminum, triisobutylaluminum, ethoxydiethylaluminum, trioctylaluminum, and tridecylaluminum are particularly preferred. (Reaction product of 0 phosphite and cyclohexanetriol) This is a transesterification product of phosphite and cyclohexanetriol represented by the following general formula.

X (In the formula, R2 is an alkyl group or aryl group having 2 to 6 carbon atoms) Examples of the above phosphite include triethyl phosphite, tripropyl phosphite, tributyl phosphite, triphenyl phosphite, etc. .

Cyclohexanetriol means that the three hydroxyl groups on the cyclohexane ring are located at 1, 2, 3, 1, 3, 5, and 1.
・It is a substituent at the 2 and 4 positions.

The reaction between phosphite and cyclohexanetriol is
This can be carried out by heating under reflux.

For example, JournalOfAlowRicSoChemic
It is carried out by the method described in alSOcietyVOl846lOp (1962), that is, by mixing phosphite and cyclohexanetriol in a molar ratio of 1 to 1.2, and heating the mixture at 75 to 180°C under reflux for 3 to 6 hours. .

The resulting reaction product can be used as it is without isolation. The product thus obtained is a mono-substituted product, a di-substituted product, a tri-substituted product, or a mixture thereof of honephaite and cyclohexanetriol as shown below, and it is thought that the tri-substituted product is the main component. However, di- and tri-substituted compounds are considered to be effective.

Moreover, the presence of monosubstituted products is not harmful. When equimolar amounts of phosphite and cyclohexane are used, the product is mostly trisubstituted. Alcohols having 2 to 6 carbon atoms These alcohols are linear, branched, or cyclic saturated alcohols having 2 to 6 carbon atoms, such as ethanol, propanol, isopropyl alcohol, butanol, amyl alcohol, n. -Hexyl alcohol, cyclohexyl alcohol, etc.

2 Catalyst Composition The ratio of the amounts used of each component in the present catalyst system is important, and is preferably within the following range.

When these quantitative balances are disrupted, the desired catalytic performance tends to decrease.

Nickel compound (Ni) In molar ratio to the raw material isoprene (IP), (Ni)/
(P) -0.0001 to 0.1, especially 0.0005 to 0
．． 05 is preferable.

(B) Aluminum compound (Al) Although it varies depending on the amount of lower alcohol used, generally the molar ratio (A
l)/(Ni)=1-20, preferably 2-10.

(0. Reaction product of phosphite and cyclohexanetriol. 0.0 molar ratio to the nickel compound used.
05-4, preferably O, 1-2.

DAlcohols with 2 to 6 carbon atoms The amount used is important in order to better demonstrate the performance of 0 and to suppress the amount of by-products with higher boiling points than isoprene trimer. , especially when used in large amounts, may have an adverse effect on aluminum compounds.

The molar ratio to the aluminum compound is 0.1 to 2, preferably 0.2 to 1.5.

3 Catalyst Preparation Method This catalyst system is prepared by preparing each component, (B), (0
It is obtained by stepwise mixing ◎ and ◎ at once, and the monomer isoprene can also be present at this stage.

During preparation, preferably at a temperature of 0 to 80°C,
An active catalyst system is obtained by adding the nickel compound to the solvent, then adding the reaction product of phosphite and cyclohexanetriol previously mixed in lower alcohol D, stirring, and then adding the aluminum compound.

In some cases, catechols, quinones, nitriles, etc. may be added to suppress high-boiling substances produced as by-products. The solvent used here is preferably one used in the trimerization step described below.

4. Catalytic trimerization As a solvent for catalytic trimerization of isoprene, inert solvents that are not harmful to the catalyst system, such as aromatic hydrocarbons such as benzene, toluene, and xylene, or aliphatic hydrocarbons such as hexane and heptane are used alone. Aromatic hydrocarbons can be used either alone or as a mixture of two or more kinds, and aromatic hydrocarbons are particularly preferred since they are convenient for the solubility of the catalyst.

The reaction temperature is 60-200°C1, preferably 80-150°C.
℃ range.

The reaction pressure can be either normal pressure or elevated pressure, but is preferably 10 atm or less from the point of view of equipment economy.

0 Example 9 Examples 1 to 6 In a 500 ml autoclave purged with argon gas, the solvents shown in Table 1, a nickel compound, an aluminum compound, a reaction product of phosphite and cyclohexanetriol (tri-substituted product), and Alcohols having 2 to 6 carbon atoms were charged in amounts shown in Table 1, and mixed at 40°C to prepare catalysts.

The reaction product of the above phosphite and cyclohexanetriol is obtained by adding 3 to 4 drops of triethylamine dropwise to an equimolar mixture of triethyl phosphite and cyclohexanetriol, and refluxing begins at 75°C, and by-product ethanol is distilled off. The mixture obtained by heating and stirring at 130° C. for 3 hours was used.

Next, a predetermined amount of isoprene is charged and stirred at a predetermined temperature for a predetermined time.

Methanol is then added to decompose the catalyst and the products are separated by distillation. 2m77! Isoprene trimer fractions with a boiling point of 90 to 110° C. were obtained under reduced Hg pressure, and the structural isomer compositions of these fractions were confirmed by gas chromatography analysis and ozonolysis.

The results are shown in Table 1. In addition, TMCD in the table
T (trimethylcyclododecatriene) has the following formula. Comparative Examples 1 to 5 As Comparative Example 1, an isoprene trimer was produced in the same manner as in Example 1 except that the reaction product of triethyl phosphite and cyclohexanetriol and alcohol were not used.

As Comparative Example 2, an isoprene trimer was produced in the same manner as in Example 1 except that no alcohol was used and triethyl phosphite was used without reacting cyclohexanetriol.

Comparative Example 3 was a reaction between triethyl phosphite and cyclohexanetriol, in which cyclohexanetriol was not used and trihydroxybenzee 7 148 o
An isoprene trimer was produced in the same manner as in Example 1, except that the same procedure was used as in Example 1, except that the same procedure was used as in Example 1.

As Comparative Example 4, a reaction product obtained by reacting triethyl phosphite with cyclohexanetriol without using cyclohexanetriol and with hexanetriol (1, 2, 6 monosubstituted product) was used, and the other conditions were the same as in Example 1. An isoprene trimer was produced in the same manner.

Comparative Example 5 is a reaction product of triethyl phosphite and cyclohexanetriol without using cyclohexanetriol, but using a reaction product obtained by reacting cyclohexanediol (1 and 2 monosubstituted product). Manufactured trimmers.

These results are shown in Table 2 together with the results of Example 1.

As is clear from these results, in the catalyst system that does not contain the reaction product of phosphite and cyclohexanetriol and alcohol (Comparative Example 1), the trimer selectivity decreases, and the content of cyclic bodies in the trimer and the all-trans This results in an unfavorable result in that the body content decreases significantly and the amount of by-products of high-boiling substances including polymers increases.

In addition, in the catalyst system using triethyl phosphite that does not contain alcohol and is not reacted with cyclohexanetriol (Comparative Example 2), the trimer selectivity decreases (the amount of dimer by-product increases), and the cyclic This results in an unfavorable result in which the content of In addition, a catalyst system using a reaction product obtained by reacting phosphite and cyclohexanetriol without using cyclohexanetriol and reacting with trihydroxybenzene (Comparative Example 3), and a catalyst system using a reaction product obtained by reacting hexanetriol with In both systems (Comparative Example 4), the trimer selectivity decreased and the content of cyclic bodies in the trimer significantly decreased, which is an unfavorable result.

In addition, in the reaction between phosphite and cyclohexanetriol, a catalyst system (
In Comparative Example 5), the trimer selectivity was significantly reduced (the amount of high-boiling substances increased), which was an unfavorable result. From the above, it can be said that the catalyst component of the present invention (ie, the reaction product of phosphite and cyclohexanetriol) has extremely specific actions and effects.

Claims (1)

[Claims] 1. A method for producing a trimer of isoprene by catalytic oligomerization, which comprises the following (A) and (B):
, (C) and (D). (A) Nickel compound selected from olefin coordination complexes of nickel, divalent organic acid salts, or divalent chelate salts (B) Aluminum compound AlRm(OR^1)_3_-_m ( In the formula, R and R^1 are an alkyl group or an aryl group having 1 to 10 carbon atoms, m is an integer of 1 to 3) (C) A reaction product of a phosphite represented by the following general formula and cyclohexanetriol Product P(OR^2)_3 (In the formula, R^2 is an alkyl group or aryl group having 2 to 6 carbon atoms) (D) Alcohols having 2 to 6 carbon atoms.