JPS6118726A - Dimerization of hydrocarbons having at least one hydrogen atom in the alpha-position and beta-gamma unsaturated double bond - Google Patents

Abstract

PURPOSE:In the dehydrative dimerization of hydrocarbons having at least one hydrogen in the alpha-position and a beta-gamma unsaturated bond by light irradiation, a polyacid or its salt is used as a photochemical catalyst to enable selective production of the objective compound. CONSTITUTION:A substituted or unsubstituted hydrocarbon having at least one hydrogen atom in the alpha-position and a beta-gamma unsaturated bond is subjected to dehydrogenative dimerization in the presence of at least one or salt selected from the group consisting of polymolybdic acid, polytungstic acid, polytitanic acid, polyvanadic acid, polyniobic acid, polytantalic acid or their salts, under irradiation with sun light, tungsten lamp, mercury lamp, xenon lamp or deuterium lamp to produce the dimer of the hydrocarbon which is used as an intermediate of agricultural chemicals or medicines with industrial advantages.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application The present invention is directed to hydrogen atoms having at least one hydrogen atom in the α position and β-
A method for dimerizing substituted or unsubstituted hydrocarbons having a γ-unsaturated double bond. According to this method, various compounds can be produced that can be used as intermediates for the synthesis of compounds useful for agricultural chemicals, medicines, and other uses. can do.

Conventional Technology It has been known that olefins are dehydrogenated and dimerized by irradiating them with light in the presence of a sensitizer such as benzophenone, but this dehydrogenation reaction of olefins is a side reaction. However, the selectivity for dimer formation is low, and it cannot be used industrially.Problems to be Solved by the InventionThe present inventors have solved the problems of the prior art described above. In order to solve the problem and develop a dimerization method that can selectively dimerize substituted or unsubstituted hydrocarbons having at least one hydrogen atom at the α-position and a β-r unsaturated double bond. I've been doing research.

Means for Solving the Problems As a result of intensive research, the present inventors found that by irradiating light in the presence of a polyacid or its salt, a polyacid having at least one hydrogen atom at the α position and β-γ It has been found that substituted or unsubstituted hydrocarbons having unsaturated double bonds can be selectively dehydrogenated.

In the present invention, substituted or unsubstituted hydrocarbons having at least one hydrogen atom at the α-position and a β-γ unsaturated double bond (hereinafter simply referred to as "allylic hydrocarbons") are selectively dehydrogenated. Examples of the polyacid or its salt used as a photocatalyst in the process include polymolybdic acid, polytungstic acid, polytitanic acid, 2-rivanadic acid, l
Isopolyacid compounds such as liniobic acid, polytantalic acid and I-liuranic acid, and various heteroatoms with Keggin-type and Dawson-type structures, such as B * Mn + Fe +
Col S L r P r A@l sb t E
Examples include heteropolyacids such as u l Ce r Th. Since these polyacids only need to exist in the form of ions in the reaction system, they can also be used as any salt. Typical examples of such salts include alkyl ammonium salts such as methylammonium salt, diethylammonium salt, isozolobylammonium salt, and zorobylammonium salt, as well as alkali metal salts such as sodium and potassium salts, and guanidinium salts. You can also use either. These polyacids or their salts can be used alone or as an arbitrary mixture of two or more.

The amount of polyacid or its salt used as a photocatalyst in the dimerization reaction of the present invention is not particularly limited, but is generally 1/100 to 1/1
They are used in a molar ratio of 10, preferably 1/100 to 1/10.

As mentioned above, the allylic hydrocarbon used as a starting compound in the present invention is a substituted or unsubstituted hydrocarbon having at least one hydrogen atom at the α-position and a β-r double bond. You can use whatever you have. Representative examples of such allylic hydrocarbons include propylene, 1-butene, 2-butene, isobutyne, 1-bentene, 2-pentene, 1-hexene, 2
-Aliphatic allylic hydrocarbons such as hexene, 3-bexene, cyclohexene, cyclooctene, cyclopentene, and further having one or more CnH2n+1 substituents, such as 1-methylcyclohexene-2,1-ethylcyclooctene- alicyclic allylic hydrocarbons such as benzene and one or more CnI (12n+1 substituents) such as toluene, ethylbenzene, xylene, and aromatic allylic hydrocarbons such as α-methylstyrene. I can give it to you.

The dimerization reaction of the present invention can be carried out, for example, by converting the allyl hydrocarbon into acetonitrile, dimethylformacide, DMSO, acetone, sulfolane, methylene dichloride, diradical ethylene,
By dissolving in any solvent such as n-hexane and water or a mixture of two or more of these solvents, or by adding the above &IJ acid or its salt and irradiating it with light, using a solvent. implement.

The wavelength of the light used for light irradiation is good if it includes a wavelength that absorbs polyacid or its salt. , 7. For example, the dimerization reaction can be carried out using sunlight, a tungsten lamp, a mercury lamp, a xenon lamp, a deuterium lamp, etc. The reaction conditions for the dimerization reaction according to the present invention are not particularly limited, but generally 0 ~100℃・preferably 20~30℃
The reaction can be carried out at a temperature of 2 to 100 hours.

After completion of the reaction, the produced dimer can be easily separated from the reaction solution by a conventional method, for example, by extraction with n-hexane and separation using silica gel column chromatography with hexane as a developing solvent.

Function The mechanism of action of the polyacid or its salt used as a photocatalyst in the present invention is not necessarily clear, but for example, when Decatungstae (Bu4N)4W1oO5□ is used as a photocatalyst, W100!52'- is allyl type. It is photoreduced by hydrocarbons to become a reduced species that does not have photocatalytic action, such as RuO211ro.
a P to2. By coexisting with an oxidation catalyst such as P t , it returns to its original state in the reaction system and comes to act as a photocatalyst again.

EXAMPLES The present invention will be explained below with reference to Examples, but it goes without saying that the scope of the present invention is not limited to these Examples.

Example 1 - Add 1.01 (0.3mM) of decatangstate ("4") to 50g of acetonitrile in a Gyrex reaction test tube.
N) 4W10032 and RuO2200m9 (1,5m
A solution containing M) is charged, and cyclohexene 2 is added to this.
, 111 (25mM) was added. Next, the reaction tube was irradiated with light under an argon atmosphere to carry out the following dimerization reaction.

Note that the light irradiation was carried out using a 450 W high-pressure mercury lamp as a light source, and the reaction was carried out at a temperature of 30° C. for 15 hours.

The yield of the obtained product 3.3'-1r cyclohexenyl was 0.13y (conversion rate near, 2 parts, selectivity: 90 parts). The results of tracking the reaction using a gas chromatograph are shown in FIG. 1 (see curve (a)).

Example 2 In Example 1, the amount of decatching state used is 1.0
1 (0.3mM), the amount of raw material cyclohexene added was 2
．． 1. (N25mM), light irradiation time was 12 hours, Ru
Same as Example 1 except that O2 was not added.
0.067# of 3'-bicyclohexenyl was obtained (conversion rate: 3.4%, selectivity: 95L%).

The reaction was followed by gas chromatography, and the results were as shown in curve (b) in Figure 1.

Example 3 In Example 1, the amount of decatching state used was 5.0.
11 (1,'5mM), the amount of N agent cyclohexene added was 1.059 (12,5mM), and the light irradiation time was 8.
3,3'-bicyclohexenyl 0.10.9
(Conversion rate: 10.2%, selectivity: 921°) The reaction was followed by gas chromatography and the results were as shown in curve (c) in Figure 1.

Examples 4 to 6 In the same manner as in Example 1, the starting compounds shown in Table 1 below were photodimerized to obtain dimers. The structure of the resulting dimer was identified by M(t), IR and GC-MS analysis).

The conversion rate and selectivity of the reaction were as shown in Table 1.

-1゛Effect As explained above, according to the method of the present invention, by irradiating light in the presence of a polyacid or its salt, a β-γ unsaturated dihydrogen having at least one hydrogen atom at the α-position can be obtained. (substituted or unsubstituted hydrocarbons having heavy bonds) can be selectively dehydrogenated and trimerized.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the progress of the photodimerization reactions in Examples 1 to 3, in which the vertical axis shows the amount of product and the horizontal axis shows the reaction time (light irradiation time).

Claims (1)

[Claims] 1. A substituted or unsubstituted hydrocarbon having at least one hydrogen atom at the α-position and a β-γ unsaturated double bond is irradiated with light in the presence of a polyacid or a salt thereof. The method for dimerizing hydrocarbons, which comprises dimerizing a hydrogen atom at the α-position by dehydrogenating the hydrogen atom. 2. The method according to claim 1, wherein the polyacid is at least one selected from polymolybdic acid, polytungstic acid, polytitanic acid, polyvanadic acid, polyniobic acid, polytantalic acid, and polyuranic acid.