# Patent

## Title
Process for production of carbonyl compound

## Abstract

A process for producing a carbonyl compound corresponding to an olefin, the process comprising reacting the olefin with molecular oxygen in a water-containing liquid phase comprising a palladium catalyst, a vanadium compound, and a heteropoly acid having a heteropoly anion represented by the Formula: [XaMbM′cOd]n− wherein X is any of elements selected from P, Si, and S; a represents an integer of 1 or 2; M and M′ represent any of elements selected from Mo, W, V, Ta, and Nb; b and c represent an integer of 0 or more; d represents an integer of 1 or more; and n represents an integer of 1 or more.

## Background
TECHNICAL FIELD
The present invention relates to a process for producing a carbonyl compound.
BACKGROUND ART
As a process for producing a carbonyl compound by direct oxidation of an olefine, the Wacker process, which uses a PdCl2—CuCl2 catalyst, has been known for a long time. However, there have been problems with corrosion of equipment by chlorine, by-products containing chlorine compounds, and the like in the Wacker process. Moreover, there are problems that the reaction rate markedly decreases as the carbon number of an olefin material increases and that the reactivity of an internal olefin is low, and the process thus has not been used industrially except in the manufacture of lower carbonyl compounds such as acetaldehyde, acetone, and the like. As a method to resolve these problems, Patent Document 1 discloses a method of carrying out a reaction adding a redox metal under the presence of palladium and a heteropoly acid.

    Patent Document 1: Patent Document 1: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 63-500923


DISCLOSURE OF THE INVENTION
Problem which the Invention is to Solve
However, this method cannot satisfy the needs from the perspective of productivity because the activity per a unit amount of Pd is low. The present invention provides a process for producing a carbonyl compound, the process having a good activity per a unit amount of Pd and showing excellent productivity.
Means for Solving the Problem
Specifically, the present invention relates to a process for producing a carbonyl compound corresponding to an olefin, the process comprising reacting the olefin with molecular oxygen in a water-containing liquid phase comprising a palladium catalyst, a vanadium compound, and a heteropoly acid having a heteropoly anion represented by the Formula: [XaMbM′cOd]n−
wherein X is any of elements selected from P, Si, and S;
a represents an integer of 1 or 2;
M and M′ represent any of elements selected from Mo, W, V, Ta, and Nb;
b and c represent an integer of 0 or more;
d represents an integer of 1 or more; and
n represents an integer of 1 or more.
Effect of the Invention
According to the present invention, carbonyl compounds such as ketone compounds, and the like can be produced in a preferred yield.


BEST MODES FOR CARRYING OUT THE INVENTION
First, the description will be made of a heteropoly acid having a heteropoly anion represented by the Formula: [XaMbM′cOd]n−
wherein, X is any of elements selected from P, Si, and S;
a represents an integer of 1 or 2;
M and M′ represent any of elements selected from Mo, W, V, Ta, and Nb;
b and c represent an integer of 0 or more;
d represents an integer of 1 or more; and
n represents an integer of 1 or more.
The upper limit of n is, but not limited to, generally 20, and preferably 10. In the heteropoly anions represented by such a formula, P is particularly preferred for X, and V, Mo, and W are particularly preferred for M and M′.
The composition of typical heteropoly anions includes XMXM′12-xO40, XMxM′12-xO42 wherein x represents an integer satisfying the inequality: 0≦×≦12, XMyM′10-yO34 wherein y represents an integer satisfying the inequality: 0≦y≦10, XMzM′11-zO39 wherein z represents an integer satisfying the inequality: 0≦z≦11, and X2MuM′18-uO62 wherein u represents an integer satisfying the inequality: 0≦u≦18. Specifically, such heteropoly acids include H4PV1Mo11O40, H5PV2Mo10O40, H3PMo12O40, H3PW12O40, H3PMoxW12-XO40 wherein x represents an integer satisfying the inequality: 0<x<11, H6P2Mo18O62, and the like.
Besides, the commercially available one itself may be used for the above heteropoly acid, and the acid may be synthesized according to a known method. Additionally, the proton type can also be used for the heteropoly acid, and an acid salt that substitutes any of the protons of the heteropoly acid by an ammonium salt or an alkali metal such as Na+, K+, etc. can also be used. Additionally, a single type of these heteropoly anions may also be used, and these may be used as a mixture of a plurality of the types.
Although a preferred additive amount of the heteropoly acid depends on the type of the heteropoly acid, in many cases, the range of the concentration in a water-containing liquid phase is desirably 0.1 mmol/L to 100 mmol/L, and more preferably 1 mmol/L to 50 mmol/L. The amount of the heteropoly acid is 50 to 0.1 mol per 1 mol of palladium, preferably 20 to 0.5 mol per 1 mol of palladium, and more preferably 1 to 10 mol per 1 mol of palladium.
In the present invention, the vanadium compound is not limited if soluble in the reaction solution, but includes those having a vanadium-oxygen bond such as, for example, VO2+ and VO3−, VO43−, VO2+, and the like. Preferably, the compound that can be used is the compound represented by the general formula: AVO3 or VO(B)m wherein A represents a monovalent cation; B represents an anion; and m represents an integer of 1 or more. The anions represented by B include organic anions such as acetylacetonato and inorganic anions such as sulfate ions, and the specific examples include NH4VO3, NaVO3, VOSO4, and (CH3COCHCOCH3)2VO.
The additive amount of the vanadium compound depends on the type of the heteropoly acid and a vanadium source used, and is preferably 0.5 to 20 g-atm per 1 mol of the heteropoly acid.
The palladium sources that can be used in the present invention include, for example, palladium metals, palladium compounds, and the mixtures thereof.
Examples of the palladium compounds include, for example, organic acid salts of palladium, oxyacid salts of palladium, palladium oxide, and palladium sulfide. In addition, the examples include these salts and oxides, organic or inorganic complexes of the sulfide, and the mixtures thereof.
Examples of the organic acid salts of palladium include, for example, palladium acetate and palladium cyanide. Examples of the oxyacid salts of palladium include, for example, palladium nitrate and palladium sulfate. Examples of these salts and oxides, and organic or inorganic complexes of the sulfide include, for example, tetaaminepalladium (II) nitrate, bis(acetylacetonato)palladium, and the like. Among them, the organic acid salts of palladium or oxyacid salts of palladium are preferred, and palladium acetate is more preferred.
As a water-containing liquid phase of the present invention, water and a water-containing liquid phase in which a suitable organic solvent is added to water can be used. Nitrile compounds are preferred for such an organic solvent, and acetonitrile is preferred among these.
Since the additive amount of the organic solvent depends on the type of an olefin used, the amount cannot be categorically defined, but the preferred ratio by weight of acetonitrile/water is 4.8 to 0.01, and preferably 3 to 0.2 when cyclohexene, for example, is used as an olefin.
In the present invention, the reaction adding palladium, the heteropoly acid, and the vanadium compound can be performed by further adding one or more types of additives, and examples of a particularly preferred additive include iron compounds. Although a known compound can be used as an iron compound, the compounds can include, for example, iron sulfate, iron alum (ammonium iron sulfate), iron nitrate inorganic salts such as iron phosphate, iron citrate, organic acid salts such as iron acetate, iron phthalocyanine, complexes such as iron acetylacetonato, iron oxide, and the like. Among them, the inorganic salts are preferably used, and iron sulfate or iron alum is suitable. The concentration of the preferred iron compound is 0.01 to 100 mol per 1 mol of the heteropoly acid, and more preferably 0.1 to 50 mol per 1 mol of the heteropoly acid.
The olefin that is used in the present invention is not limited, but a cyclic ketone can be obtained efficiently by oxidation of a cyclic olefin in particular. The examples of the cyclic olefin include a cyclic olefin having the carbon number of 4 to 20. These include, for example, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclododecene, cyclooctadecene, and the like. The cycloolefin that is more preferably used is cyclohexene, and cyclohexanone is produced efficiently from cyclohexene.
Pure oxygen or air can be used as molecular oxygen, and the oxygen may be used as a gas containing molecular oxygen by diluting these gases with an inert gas such as nitrogen, helium, or the like. The amount of oxygen used is usually adjusted by the pressure of the oxygen-containing gas that is injected into a reaction system, and the range of preferably 0.01 to 10 MPa and more preferably 0.05 to 5 MPa as oxygen partial pressure or as gauge pressure is set. This reaction gas, as a total volume, may be injected before reaction, or the reaction may be carried out by continuously supplying the gas, such as by blowing in the system during the reaction, and the like.
The reaction of the present invention is usually carried out under acidic conditions, and the acidity of the solution is desirably adjusted by the additive amount of the heteropoly acid. However, for the case using acid salts of the heteropoly acid and other cases, more preferred reaction results may also be obtained by adjusting the acidity while adding a small amount of another protonic acid.
The protonic acids other than the heteropoly acid include inorganic acids, organic acids, solid acids, and the like, and the inorganic acids include hydrochloric acid, binary acid (hydracid) such as hydrofluoric acid, sulfuric acid, and oxo acid (oxyacid) such as nitric acid. Examples of the organic acids include, for example, formic acid, aliphatic carboxylic acid (e.g., acetic acid), alicyclic carboxylic acid (e.g., cyclohexanecarboxylic acid), aromatic carboxylic acid (e.g., benzoic acid), sulfonic acid, and the like. The sulfonic acid includes, for example, alkyl sulfonic acid (e.g., methanesulfonic acid or ethanesulfonic acid), arylsulfonic acid (e.g., benzenesulfonic acid, p-toluenesulfonic acid or naphthalenesulfonic acid), and the like. Examples of the solid protonic acids include, for example, ion exchange resin (e.g., sulfonic acid-type ion exchange resin, etc.), acidic zeolite and the like, and sulfated zirconia.
For the additive amount of the protonic acid other than the heteropoly acid, the total amount of the separable proton is needed to be adjusted lower than the proton that was contained in the heteropoly acid, and is desirable to be 1/2 or less, and more preferably 1/10 or less.
The reaction is usually performed in a temperature range of 0 to 200° C., preferably 10 to 150° C., and more preferably 30 to 100° C. The reaction is usually performed in a pressure range of 0.01 to 10 MPa (absolute pressure), preferably 0.05 to 7 MPa (absolute pressure), and more preferably 0.1 to 5 MPa (absolute pressure). The reaction can be performed by a batch, a semibatch, a continuous process or the combinations thereof. The catalyst may be added beforehand in a reactor to initiate the reaction, or may be continuously supplied to carry out the reaction.
The reaction solution or reaction gas, both of which contain a product, is collected to isolate a carbonyl compound such as a desired ketone and the like. The produced ketone compound can be separated usually by distillation, phase separation, and the like.
EXAMPLES
Hereinafter, the present invention will be further illustrated in detail by the Examples, but is not limited to the following Examples.
Example 1
The following mixture was placed in a 120-ml autoclave, and was reacted at 323 K for 2 hours under 2 MPa of air and 3 MPa of nitrogen (0.42 MPa of oxygen partial pressure, 4.58 MPa of nitrogen partial pressure) during stirring the mixture with a stirring bar. The obtained reaction mass was analyzed by gas chromatography. The results are shown in Table 1.

(Mixture)

Cyclohexene: 1.6 g (20 mmol),

Solvent: acetonitrile/water (3.0 ml/2.0 ml),

H4PV1Mo11O40 (manufactured by NIPPON INORGANIC COLOUR & CHEMICAL CO., LTD.): 92 mg (0.04 mmol),

VOSO4.nH2O (KANTO CHEMICAL CO., INC.): 59 mg,

Pd(OAc)2: 4 mg.

Example 2
The reaction was performed in the same manner as Example 1 except that 58 mg of iron alum (FeNH4(SO4)2.12H2O, KANTO CHEMICAL CO., INC.) was added. The results are shown in Table 1.
Example 3
The reaction was performed in the same manner as Example 1 except that 33 mg of iron sulfate (FeSO4.nH2O, Nacalai) was added. The results are shown in Table 1.
Example 4
The reaction was performed in the same manner as Example 3 except that acetonitrile/water (1.5 ml/1.0 ml) was used as a solvent and VOSO4.nH2O (KANTO CHEMICAL CO., INC.) was 30 mg. The results are shown in Table 1.
Example 5
The reaction was performed in the same manner as Example 2 except that acetonitrile/water (2.0 ml/3.0 ml) was used as a solvent. The results are shown in Table 1.
Example 6
The reaction was performed in the same manner as Example 2 except that 11 mg of NaVO3 (Nacalai) was used instead of VOSO4.nH2O. The results are shown in Table 1.
Example 7
The reaction was performed in the same manner as Example 2 except that H3PMo12O40 (NIPPON INORGANIC COLOUR & CHEMICAL CO., LTD.) was used as a heteropoly acid and VOSO4.nH2O was 143 mg. The results are shown in Table 1.
Example 8
The reaction was performed in the same manner as Example 6 except that 33 mg of iron sulfate (FeSO4.nH2O, Nacalai) was added instead of iron alum and acetonitrile/water was 1.5 ml/1.0 ml. The results are shown in Table 1.
Comparative Example 1
The reaction was performed in the same manner as Example 2 except not adding VOSO4.nH2O. The results are shown in Table 1.
Comparative Example 2
According to a method disclosed in Patent Document 1, K5H4PMo6V6Mo40 was prepared as follows. Specifically, 7.32 g of sodium metavanadate was dissolved into 38 ml of distilled water, and the mixture was kept at 90° C. In addition to this, 8.07 g of sodium molybdate was added to 12 ml of distilled water, and the mixture was heated to 90° C. Then, the above-prepared aqueous sodium metavanadate solution was added thereto. To this mixture was added 5 ml of 85% phosphoric acid. After the mixture was cooled, and stirred during adding 8 g of potassium nitrate, and the solid was then filtrated. The solid was recrystallized from 0.25 M of H2SO4 to yield K5H4PMo6V6O40.
To acetonitrile/water (1.3 ml/3.8 ml) was added 8 mg of Pd(NO3)2, 160 mg (0.09 mmol) of prepared K5H4PMo6V6O40, and 120 mg of Cu(NO3)2.3H2O, and further added 7.7 mg (0.08 mmol) of sulfuric acid. Then, 210 mg (2.6 mmol) of cyclohexene was added thereto. The mixture was placed in a 120-ml autoclave, and was reacted at 323 K for 2 hours under 2 MPa of air and 3 MPa of nitrogen (0.42 MPa of oxygen partial pressure, 4.58 MPa of nitrogen partial pressure) during stirring with a stirring bar. Table 1 shows the results in which the obtained reaction mass was analyzed by gas chromatography.














TABLE 1












Acetamide/




Vanadium
Iron
Conversion
Cyclohexanone
TOF
Cyclohexanone



Heteropoly acid
compound
compound
rate
selectivity
(h−1)
(mol %)






















Example 1
H4PV1Mo11O40
VOSO4
—
14
78
69
0.0


Example 2
H4PV1Mo11O40
VOSO4
Iron alum
38
95
209
1.0


Example 3
H4PV1Mo11O40
VOSO4
Iron
24
96
132
1.9





sulfate






Example 4
H4PV1Mo11O40
VOSO4
Iron
24
97
126
1.5





sulfate






Example 5
H4PV1Mo11O40
VOSO4
Iron alum
32
95
162
2.1


Example 6
H4PV1Mo11O40
NaVO3
Iron alum
28
96
138
1.5


Example 7
H3PMo12O40
VOSO4
Iron alum
25
96
126
0.0


Example 8
H3PMo12O40
VOSO4
Iron
22
95
118
4.0





sulfate






Comparative
H4PV1Mo11O40
—
Iron alum
2
78
10
0.0


Example 1









Comparative
K5H4PMo6V6O40
—
Copper
23
73
7
119


Example 2


nitrate









In Table 1, the conversion rate represents the conversion rate of cyclohexene, and TOF (h−1) means (number of moles generated for cyclohexanone)/(number of moles of Pd)/(reaction time). Acetamide/Cyclohexanone (mol %) represents the ratio between generated cyclohexanone and acetamide.
INDUSTRIAL APPLICABILITY
The present invention can be a useful process for producing a carbonyl compound such as cyclohexanone.

## Claims

1. A process for producing a carbonyl compound corresponding to an olefin, the process comprising reacting the olefin with molecular oxygen in a water-containing liquid phase comprising a palladium catalyst, a vanadium compound, and a heteropoly acid having a heteropoly anion represented by the Formula: [XaMbM′cOd]n−
wherein X is any of elements selected from P, Si, and S;
a represents an integer of 1 or 2;
M and M′ represent any of elements selected from Mo, W, V, Ta, and Nb;
b and c represent an integer of 0 or more;
d represents an integer of 1 or more; and
n represents an integer of 1 or more.

2. The process according to claim 1, wherein the vanadium compound is a vanadium compound represented by the formula: AVO3 or VO(B)m 
wherein A represents a monovalent cation;
B represents an anion; and
m represents an integer of 1 or more.

3. The process according to claim 1, wherein the water-containing liquid phase is a water-containing liquid phase containing an organic solvent.

4. The process according to claim 1, wherein the water-containing liquid phase is a water-containing liquid phase containing acetonitrile.

5. The process according to claim 1, wherein the olefin is a cyclic olefin and the carbonyl compound is a cyclic ketone.

6. The process according to claim 1, wherein the olefin is cyclohexene and the carbonyl compound is cyclohexanone.

7. The process according to claim 1, wherein the reaction is performed in the presence of an iron compound.