JPS5965026A - Preparation of 1,6-dimethyl-1,5-cyclooctadiene - Google Patents

Abstract

PURPOSE:To obtain the titled substance, by dimerizing isoprene in the presence of a catalyst consisting of an iron carboxylate or a beta-diketonic compound, an organoaluminum compound or organomagnesium compound and a 2,2'-dipyridyl derivative containing an electron donative substituent group. CONSTITUTION:Isoprene is catalytically cyclodimerized to give the titled substance. In the process, a catalyst consisting of (A) an iron carboxylate, e.g. iron (III) acetate, iron (II) lactate or iron (II) benzoate, or a beta-diketonic compound of formula I (n is 2 or 3; R' and R'' are alkyl, aryl or aralkyl), (B) a compound of formula II (R<1> is alkyl, aryl, etc.; X is R<1>, alkoxyl, H, etc.; l is 1-3) or formula III (R<2> is alkyl, aryl, etc.; Y is halogen; m is 1 or 2) and (C) a compound having an electron donative substituent group of formula IV (R<3>-R<6> are alkyl, alkoxyl, amino, H, etc.) is used to give the titled substance in high selectivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for selectively producing dimethylcyclooctadiene (hereinafter abbreviated as traditional DM00D), particularly its 1,6-dimethyl form, by catalytically cyclic trimerizing isoprene. It is something.

Conventionally, methods for catalytically producing DM (!OD) include a method using a nickel-based complex catalyst and a method using an iron-based complex catalyst.
110 and JP-A-53-90240, the products obtained by these methods are 1,5-dimethyl-1,5-cyclooctadiene (hereinafter referred to as 1 .5-DMOCID) is the main one. On the other hand, DMCOD obtained by the latter method using an iron-based complex catalyst is 1.6-cymethyl-1.5=
Cyclooctadiene C (hereinafter abbreviated as l,' 6-DMCOD) is the main one.

As a method for obtaining 1,6-DM (!OD) using an iron-based complex catalyst, a method using iron acetylacetonate, 2゜2'-dipyridyl and triethylaluminum is
ll, C! hem, Soc, J,, 39°2425 (
(1966), however, this method was disadvantageous industrially because the concentration of the catalyst used was high relative to the raw material isoprene, and the amount of solvent used was large. In addition, the proportion of 1.6-dimethyl form in MOOD is approximately 80%.
Therefore, the selectivity was not satisfactory.

The present inventors conducted research to improve the problems in the method described in the above literature, and as a result, the present inventors used a compound in which an electron-donating substituent was added to 2,2'-dipyridyl as a ligand for the central metal iron. The present invention was achieved by discovering that, by doing so, the yield of DMOOD and the selectivity of 1.6-DMOOD were improved.

The present invention provides a method for producing dimethylcyclooctadiene by catalytically cyclic trimerizing isoprene, comprising (a) an iron carboxylate or a β-diketone compound, (b) the general formula % formula % (1) Here, R1 represents an alkyl group, an aryl group, an aralkyl group, or a cycloalkyl group, X is the same group as R1, an alkoxy group, an aryloxy group, or hydrogen, and t is 1 to 3. an aluminum compound or an organomagnesium compound represented by the general formula % (2) (where R2 represents an alkyl group, an aryl group or an aralkyl group, Y is a halogen, and m is 1 or 2), and (c) 1, characterized in that a catalyst containing three components of a 2,2-dipyridyl derivative having an electron-donating substituent is used;
．． This is a method for producing 6-dimethyl-1,5-cyclooctadiene.

Among the iron compounds used in the present invention, the carboxylic acid salts are ferrous or ferric salts of aliphatic, alicyclic, or aromatic monovalent or polyvalent carboxylic acids, each having 1 carbon number.
-20 aliphatic, C7-20 alicyclic, or C7-20 carboxylic acids, specifically iron acetate (
■), iron propionate (I[), iron butyrate (1), iron valerate (I[), iron caproate (i), iron enanthate (
■), iron octenoate (■), iron undecylate (■), iron laurate (■), iron tridecylate (X), iron pentadecylate (■), iron (II) phosphate, cyclohexanecarboxylic acid Iron (■), iron naphthenate (■), iron decalin carboxylate (■), iron benzoate (X), iron toluate (][), iron dimethylbenzoate (■), iron phenylbenzoate (l, etc.) Iron β-diketone compounds are iron (I[) or iron (■) with β-diketone coordination 1.
1. -Compound 7・General formula 1°(R'-(!-C+horse-
g-R”).

It is expressed as In the formula, n is 2 or 3, and R' and W represent an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 8 carbon atoms, or an aralkyl group having 7 to 8 carbon atoms. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, 1-propyl group, n-butyl group, 5ea-butyl group, tert-butyl group, hexyl group, octyl group, dodecyl group, etc., and aryl group. Examples of the aralkyl group include a phenyl group, tolyl group, xyly, V group, etc., and examples of the aralkyl group include a henzyl group and a phenethyl group. Specific alkadiones such as /ta:/-2,4-dione (acetylacetone), hexane-2,4-dione,
1.3-diphenylpropane-1,3-';on, 1.
5-'; diphenyl alkadiones such as phenylpentane-2,5-dione and 1-phenylbutane, 3
Examples include iron compounds coordinated with a monophenyl alkadione such as -';one and l-phenylpentane-1,3-dione.

The alkyl group of R1 in the organoaluminum compound of general formula (1) used in the present invention preferably has 1 to 12 carbon atoms, the aryl group preferably has 6 to 8 carbon atoms, and the aralkyl group preferably has 7 to 8 carbon atoms, Further, the cycloalkyl group preferably has 6 to 8 carbon atoms.

The alkoxy group of X preferably has 1 to 12 carbon atoms, and the aryloxy group preferably has 6 to 8 carbon atoms. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-
Propyl group, n-butyl group, 8θC-butyl group, ter
Examples of aryl groups include phenyl, tolyl, and xylyl groups; examples of aralkyl groups include benzyl and phenethyl groups; and examples of cycloalkyl groups include t-butyl, hexyl, octyl, and dodecyl groups. , methylcyclohexyl group, dimethylcyclohexyl group, examples of alkoxy groups include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 8ec-butoxy group, tert-butoxy group, hexoxy group, octoxy group. Aluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminium, tri-n-butylaluminum, triisobutylaluminum, diisobutylaluminum hydride, trihexylaluminum, trioctylaluminum triphenyl Examples include tribenzyl aluminum, tribenzyl aluminum, tricyclohexyl aluminum, diethylaluminum ethoxide, dipropyl aluminum ethoxide, diisobutyl oxide miniram phenoxide, and the like.

The alkyl group, aryl group and aralkyl group of R2 in the organomagnesium compound of general formula (2) used in the present invention are the same as those explained for R1 above.

Examples include diisopropylmagnesium, dibutylmagnesium, diphenylmagnesium, dicyclohexylmagnesium, dibenzylmagnesium, ethylmagnesium chloride, butylmagnesium bromide and the like.

The amount of the organometallic compound used in the present invention is 1 to 200 times, preferably 2 to 20 times, the amount of the iron compound.

The 2,2'-dipyridyl derivative used in the present invention is characterized by having an electron-donating substituent, and is believed to exhibit the effects of the present invention thereby. The general formula for this compound is as follows, where R3, R4, R5, and R6 are each independently an alkyl group, an alkoxy group, an amine group, an alkylamino group, or hydrogen. However, not all of it is hydrogen. The alkyl groups of R3, R4, R5, and R6 and the alkyl group of the alkylamino group are the same as the alkyl group of R1 described above, and the alkoxy group is the same as the alkoxy group of X described above. Examples of alkylamino groups include methylamino group, dimethylamino group, diethylamine group, di-
n-propylamino group, di-mypropylamino group, di-n-butylamino group, di-5ec-butylamino group,
Examples include di-tert-butylamino group, diethylamine group, dioctylamino group, and didodecylamino group. Examples of 2,2'-dipyridyl derivatives having such an electron-donating substituent include 4-methyldipyridyl, 6-methyldipyridyl, 3-ethyldipyridyl, 4-methyldipyridyl, and 4-methyldipyridyl.
-Propyldipyridyl, octyldipyridyl, 4-dodecyldipyridyl, 4.4'-dimethyldipyridyl, 3.
5'-dimethyldipyridyl, 4-methyl-5'-ethyldipyridyl to 4.4'-diethyldipyridyl, 5-propyl-5'pyridyl, 3,4.5-)dimethyldipyridyl, 3.3',4-) dimethyldipyridyl, 4.4',
5.5'-tetramethyldipyridyl a, 4/-diethyl-5,'5'-dimethyldipyridyl, 4.4',
5゜6-ketraethyldipyridyl, 4-methyl-5-t
ert-butyl-4'-octyldipyridyl, 4-mer, 4-dobutyloxydipyridyl, 4,4'-dimethoxydipyridyl, 3, 5'-jethoxydipyridyl, 3,
5-di-5ec-butoxydipyridyl, 4cydipyridyl, 4.4', 5. 5'-tetraethoxydipyridyl, 4-ethyl-5-methoxydipyridi 4-aminodipyridyl, 3.4'-diaminodipyridyl, 5-dimethylaminodipyridyl, 4.4'-bis(dimethylamino)
Dipyridyl, 3,4'-bis(diethylamino)dipyridyl, 4-methyl-41-dimethylaminodipyridyl,
3,5-diamidimethyl-5,5'-bis(dimethylamino)dipyridyl, 4-amino-5-ethoxy-6'-
Examples include methyldipyridyl. The strength of the electron donating property of these dipyridyl derivatives is proportional to the strength of the electron donating property of the substituent and the number of substituents, and the strength of the electron donating property of the substituent is generally determined by alkyl group〉alkoxy group〉amino group. Base〉
The order is 7 dialkylamide groups, and among alkyl groups and alkoxy groups, groups with fewer carbon atoms have stronger electron-donating properties. Therefore, it is thought that the effects of the present invention are also influenced by the type and number of the groups. Particularly preferred compounds include the following. 5-mo-butylum biridyl, 4,4'-dimethyldipyridyl, 4-
Methyl-51-ethyldipyridyl, 4゜4,', 5
, 5'-detramethyldipyridyl, 5-ethquinedipyridyl, 4.4'-diaminodipyridyl to 3-butoxy-4'-methyldipyridyl, 4-aminodipyridyl,
4.4'-bis(dimethylamino)dipyridyl, 4-methyl-4'-dimethylaminodipyridyl, 4-amino-
5-Ethoxy-6'-methyldipyridyl, 4-dobutyldipyridyl, 5-propyl-57-itsuprobildipyridyl, 4.4'-di-t-butyldipyridyl, 4.4
',5-)dimethoxydipyridyl, 4,4'-jethoxy-5-methoxydipyridyl, 4,4'-di-t-butyl-5-dimethylaminodipyridyl, 4,4'-dimethyl-5,5'-bis (dimethylamino)dipyridyl.

These dipyridyl derivatives have 0
．． 05 to 20 times the mole, preferably about (Jl-5 times the mole).

The reaction of cyclic trimerization of isoprene using the catalyst of the present invention is usually carried out in the presence of a solvent, and the solvents used include aliphatic hydrocarbons such as butane, pentane, hexane, heptane, octane, cyclohexane, etc. , toluene, ginkgo, and other aromatic hydrocarbons are used.

The cyclic trimerization reaction of the present invention is carried out using a catalyst consisting of the above-mentioned iron compound, dipyridyl derivative, and organometallic compound.
It is carried out by contacting isoprene, and there is no particular restriction on the amount of catalyst used with respect to isoprene, but usually,
0, Cl001 to 0.1 molar equivalent to isoprene,
Preferably, 0.0005 to 0.01 molar equivalent of iron compound is used.

In the present invention, the above catalyst is presumed to act in the form of a compound coordinated with a dipyridyl derivative in which the iron compound is reduced in the reaction system and the iron is in a zero-valent state. Therefore, it is equally possible to add the above dipyridyl derivative to a zero-valent iron complex, such as tricarbonylbutadiene iron 2 complex, and use it as a catalyst to carry out cyclic trimerization of isoprene.

However, the catalyst of the present invention works most effectively when an iron compound and a dipyridyl derivative are added in the presence of the monomer isoprene, and then an organoaluminum or organomagnesium compound is added to initiate the trimerization reaction. It is.

It has been observed that when the catalyst is prepared in the absence of monomer, or when the iron compound is first reduced with an organometallic compound and then coordinated with the dipyridyl derivative, its catalytic activity is reduced.

The cycloditization reaction of isoprene using the catalyst of the present invention is carried out at a temperature of 0 to 150°C, preferably room temperature to 120°C, and the reaction pressure is normal pressure to the vapor pressure of isoprene, usually 1 to 201< I? /cn! It is G.

The cyclic trimerization reaction of isoprene according to the present invention can be carried out either batchwise or continuously.

After the reaction is completed, unreacted isoprene, solvent, by-products, and DMCOD are separated according to their respective boiling points to obtain the desired DMCOD.

In the following examples, the conversion rate of isoprene is expressed as the amount obtained by subtracting the amount of unreacted isoprene from the amount of raw material isoprene used, expressed as DMC! OD yield is the obtained DMOO
D is the weight % based on the total amount of raw material isoprene. Therefore, the DMCOD selectivity is the DMCOD yield divided by the isoprene conversion, which is also expressed in weight percent. Obtained DMCO
The ratio of 1°6 body and 1,5 body in D is similarly expressed as a weight ratio.

Example 1 Autoclave with electromagnetic induction stirrer (inner volume 500rnl)
) was replaced with nitrogen, and then 2.0 mmol (0,706 g) of iron acetylacetonate and 50 ml of dehydrated and degassed toluene were added under a stream of nitrogen gas. Isoprene 2 mol (1
36.2g) was added. Then 4,4'-dimethyl-2
,:l-dipyridyl 2.0 mmol (0,368 g)
, triethylaluminum 6, Ornmol (0,6
85 g) and the mixture was sealed. Raise the temperature to 90°C,
After stirring as it was for 2 hours, a dilute aqueous hydrochloric acid solution was added to decompose the catalyst. As a result of analyzing the reaction product by gas chromatography, the conversion rate of isoprene was 98.1%, and D
MC-OD is 126. Og (yield 92.5%) was obtained.

Examples 2 to 11 DM (!OD
A production reaction was performed. The results are shown in Table 1.

Comparative Examples 1 and 2 A DMOOD production reaction was carried out under the same operations and conditions as in Example 1, except that the iron compound, organometallic compound, and dipyridyl derivative were changed. The results are not shown in Table 2.

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

Claims (1)

[Claims] (]) A method for producing dimethylcyclooctadiene by catalytically cyclic trimerizing isoprene, comprising: (a)
Iron carboxylate or β-diketone compound (b) General formula % Formula % (Here, R1 represents an alkyl group, aryl group, aralkyl group, or cycloalkyl group, and X is the same group as R1, an alkoxy group, or an aryl group. is an oxy group or hydrogen, and t is 1 to 3.) Or an organoaluminum compound represented by the general formula % (where R2 represents an alkyl group, an aryl group, or an aralkyl group, and Y is a halogen; m is 1 or 2); and (c) a 2,2'-dipyridyl derivative having an electron-donating substituent. 1
, 6-dimethyl-1,5-cyclooctadiene production method. (2) The method according to claim (1), wherein the catalyst is adjusted in the presence of isoprene. (3) Adding a 2,2'-dipyridyl derivative to an iron compound,
The method according to claim 2, wherein the trimerization reaction is started after adding an organoaluminum compound or an organomagnesium compound.