CATALYST MIXTURE

Abstract

Provided is a catalyst mixture which, in a nitro group hydrogenation reaction of an aromatic nitro compound having a structure in which nitro groups and halogen atoms are directly bonded as substituents to a ring skeleton of the same ring while separated from each other, is capable of selectively hydrogenating the nitro groups and sufficiently reducing the removal of the halogen atoms from the ring. This catalyst mixture includes a catalyst which is used in a hydrogenation reaction of at least one among one or more nitro groups present in a reactant, which is an aromatic nitro compound having a structure in which one or more nitro groups and one or more halogen atoms are directly bonded as substituents to a ring skeleton of the same ring while separated from each other. This catalyst mixture further includes a base.

Claims

1. A catalyst mixture comprising a catalyst which is used in a hydrogenation reaction of at least one among one or more nitro groups present in a reactant, which is an aromatic nitro compound having a structure in which one or more nitro groups and one or more halogen atoms are directly bonded as substituents to a ring skeleton of the same ring while separated from each other, which comprises: a catalyst and a base, and the catalyst comprises a support, and Pt particles and Fe oxide particles supported on the support, and the base has a basicity stronger than at least one aromatic amine obtained as a product from the hydrogenation reaction and having one or more amino groups.

2. The catalyst mixture according to claim 1, wherein the base and a component of a solvent used in the hydrogenation reaction satisfy the condition of the following equation (1):
0.90{1000(B/Vs)}190.00(1) in the equation (1), B being a substance amount (mol) of the base, and Vs being a volume (L) of the organic solvent.

3. The catalyst mixture according to claim 1, wherein the base and the reactant used in the hydrogenation reaction satisfy the condition of the following equation (2):
0.35%{100(B/R)}75.50%(2) in the equation (2), B being a substance amount (mol) of the base, and R being a substance amount (mol) of the reactant.

4. The catalyst mixture according to claim 1, wherein a component of a solvent used in the hydrogenation reaction satisfies the condition of the following equation (3):
0.00%{100(Vh/Vs)}30.00%(3) in the equation (3), Vh being a volume (L) of an introduced water other than the yielded water, and Vs being a volume (L) of the organic solvent.

5. The catalyst mixture according to claim 4, wherein the water satisfies the condition of the following equation (4):
1.00%{100(Vh/Vs)}5.00%(4)

6. The catalyst mixture according to claim 1, further comprising a dehydrating agent.

7. The catalyst mixture according to claim 2, wherein the base and the reactant used in the hydrogenation reaction satisfy the condition of the following equation (2):
0.35%{100(B/R)}75.50%(2) in the equation (2), B being a substance amount (mol) of the base, and R being a substance amount (mol) of the reactant.

8. The catalyst mixture according to claim 2, wherein a component of a solvent used in the hydrogenation reaction satisfies the condition of the following equation (3):
0.00%{100(Vh/Vs)}30.00%(3) in the equation (3), Vh being a volume (L) of an introduced water other than the yielded water, and Vs being a volume (L) of the organic solvent.

9. The catalyst mixture according to claim 3, wherein a component of a solvent used in the hydrogenation reaction satisfies the condition of the following equation (3):
0.00%{100(Vh/Vs)}30.00%(3) in the equation (3), Vh being a volume (L) of an introduced water other than the yielded water, and Vs being a volume (L) of the organic solvent.

10. The catalyst mixture according to claim 2, further comprising a dehydrating agent.

11. The catalyst mixture according to claim 3, further comprising a dehydrating agent.

12. The catalyst mixture according to claim 4, further comprising a dehydrating agent.

13. The catalyst mixture according to claim 5, further comprising a dehydrating agent.

Description

EXAMPLE

[0101] In the following, the present invention is explained in detail by referring working examples, but the present invention is not limited by the following working examples.

<Preparation of Catalyst Mixture>

Example 1

[0102] As the catalyst, a catalyst where the Pt particles and the Fe oxide particles were carried on a carbon support {trade name NE-01M02, content of Pt: 1.0 wt %, content of Fe: 0.20 wt % available from N. E. CHEMCAT Co. (hereinafter referred to as Pt-FeOx/C as necessary)} was prepared.

[0103] In the Pt-FeOx/C, the carbon support is an activated carbon (specific surface area based on BET measurement is 900: m.sup.2/g), and the Fe oxide particles are Fe.sub.2O.sub.3 as a main component (Fe.sub.2O.sub.3 is approximately 100% based on XPS analysis).

[0104] As the base, a commercially available Na.sub.2CO.sub.3 was prepared.

[0105] A catalyst mixture was obtained by mixing 127.0 mg (water content: 0.141 mL) of Pt-FeOx/C powder and 1.0 mg of Na.sub.2CO.sub.3.

(Example 2) to (Example 5)

[0106] The catalyst mixtures of Example 2 to Example 5 were prepared in the same preparation conditions and the same raw materials as Example 1 except that the amount of Na.sub.2CO.sub.3 was changed to the value shown in Table 1.

Example 6

[0107] The catalyst mixture of Example 6 was prepared in the same preparation conditions and the same raw materials as in Example 1 except that 20 mg of a commercially available K.sub.2CO.sub.3 was used instead of the amount of Na.sub.2CO.sub.3.

Example 7

[0108] The catalyst mixture of Example 7 was prepared in the same preparation conditions and the same raw materials as in Example 1 except that 72.6 mg of a commercially available (CH.sub.3CH.sub.2).sub.3N was used instead of the amount of Na.sub.2CO.sub.3.

(Example 8) to (Example 14)

[0109] The catalyst mixtures of Example 8 to Example 14 were prepared in the same preparation conditions and the same raw materials as Example 3 except that the volume Vh (mL) of water was changed to the value shown in Table 1.

Comparative Example 1

[0110] As the catalyst of Comparative Example 1, the catalyst consisting of the powder of Pt-FeOx/C which was the same as that in Example 1 was prepared without using a base.

Comparative Example 2

[0111] The catalyst mixture of Comparative Example 2 was prepared in the same preparation conditions and the same raw materials as in Comparative Example 1 except that 200 mg of a commercially available NaCl was used without using a base.

Comparative Example 3

[0112] The catalyst mixture of Comparative Example 3 was prepared in the same preparation conditions and the same raw materials as in Comparative Example 2 except that 30 mg of a commercially available Na.sub.2SO.sub.4 was used without using a base.

Comparative Example 4

[0113] Instead of the Pt-FeOx/C used in Example 1, as the catalyst, a catalyst where the Pt particles were carried on a carbon support {trade name NE-01M00, content of Pt: 1.0 wt %, available from N. E. CHEMCAT Co. (hereinafter referred to as Pt/C as necessary)} was prepared.

[0114] In the Pt/C, the carbon support is an activated carbon (specific surface area based on BET measurement is 900: m.sup.2/g).

[0115] As the base, a commercially available Na.sub.2CO.sub.3 was prepared.

[0116] A catalyst mixture was obtained by mixing 127.0 mg (water content: 0.113 mL) of Pt/C powder and 10.0 mg of Na.sub.2CO.sub.3.

Comparative Example 5

[0117] The catalyst mixture of Comparative Example 2 was prepared in the same preparation conditions and the same raw materials as Comparative Example 1 except that the amount of Na.sub.2CO.sub.3 was changed to the value shown in Table 1.

(Comparative Example 6) to (Comparative Example 8)

[0118] The catalyst mixtures of Comparative Example 6 to Comparative Example 8 were prepared in the same preparation conditions and the same raw materials as Comparative Example 1 except that the amount of the Pt/C powder to be used was changed to 140.0 mg (water content: 0.123 mL).

Comparative Example 9

[0119] As the catalyst of Comparative Example 9, the catalyst consisting of the powder of Pt/C which was the same as that in Comparative Example 1 was prepared without using a base.

<Hydrogenation Reaction>

[0120] The hydrogenation reaction (hydrogenation reaction of nitro group) represented by the following reaction scheme (C1-11) was achieved by using the catalyst mixtures of Example 1 to Example 14 and Comparative Example 1 to Comparative Example 9.

##STR00005##

[0121] Here, in the hydrogenation reaction represented by the reaction scheme (C1-11), 2-bromo-5-nitropyridine represented by the formula (C1-1) has a heterocyclic structure having an N atom. Compared to 2-bromo-5-nitrobenzene which has a structure in which the N atom in this heterocyclic ring is replaced with a C atom, 2-bromo-5-nitropyridine is a reactant which promotes not only the main hydrogenation reaction of the nitro group (main product being 5-amino-2-bromopyridine represented by the formula (C1-2)), but also promotes easily the side reaction of the debromination reaction (by-product being 3-aminopyridine represented by the formula (C1-3).

(Reaction Conditions)

[0122] Reactant: 2.5 mmol of 2-Bromo-5-nitrobenzene represented by the formula (C1-1)

[0123] Solvent: 10 mL of toluene

[0124] Pressure of hydrogen: 0.6 MPa

[0125] Reaction temperature: 50 C.

[0126] Reaction time: 5 hours

[0127] In the hydrogenation reaction where the catalyst mixtures of Comparative Example 6 to Comparative Example 8 were used, water was added to each reaction system. The amount of water added to the reaction composition of Comparative Example 6 was adjusted to 0.444 mL, and the amount of water added to the catalyst mixtures of Comparative Example 7 and Comparative Example 8 were adjusted to be 1.000 mL.

[0128] The results obtained for the catalyst mixtures of Examples 1 to 14 and Comparative Examples 1 to 9 are shown in Table 1 and Table 2. The formula weight of Na.sub.2CO.sub.3 was 106 g mol, the formula weight of K.sub.2CO.sub.3 was 138.2 g mol, and the formula weight of (CH.sub.3CH.sub.2).sub.3N was 101 g mol.

TABLE-US-00001 TABLE 1 B R Base Vs Reactant Vh Base Base Substace Org. Solvent 100x Substace 100x Water 100x Catalyst (other Mass/ amount/ (Toluen) (B/Vs)/ amount/ (B/R)/ volume/ (Vh/Vs) structure additives) mg mmol volume/mL mol L.sup.1 mmol mol L.sup.1 mL % Ex. 1 PtFeOx/C Na.sub.2CO.sub.3 1.0 0.0094 10.0 0.94 2.50 0.38 0.141 1.41 Ex. 2 PtFeOx/C Na.sub.2CO.sub.3 5.0 0.0472 10.0 4.72 2.50 1.89 0.141 1.41 Ex. 3 PtFeOx/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 0.141 1.41 Ex. 4 PtFeOx/C Na.sub.2CO.sub.3 20.0 0.1887 10.0 18.87 2.50 7.55 0.141 1.41 Ex. 5 PtFeOx/C Na.sub.2CO.sub.3 200.0 1.8868 10.0 188.68 2.50 75.47 0.141 1.41 Ex. 6 PtFeOx/C K.sub.2CO.sub.3 20.0 0.1447 10.0 14.47 2.50 5.79 0.141 1.41 Ex. 7 PtFeOx/C (CH.sub.3CH.sub.3).sub.3N 72.6 0.7188 10.0 71.88 2.50 23.75 0.141 1.41 Ex. 8 PtFeOx/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 0.460 4.60 Ex. 9 PtFeOx/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 1.136 11.36 Ex. 10 PtFeOx/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 2.000 20.00 Ex. 11 PtFeOx/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 2.200 22.00 Ex. 12 PtFeOx/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 2.800 28.00 Ex. 13 PtFeOx/C Na.sub.2CO.sub.3 10.0 0.1048 9.0 10.48 2.50 3.77 1.620 18.00 Ex. 14 PtFeOx/C Na.sub.2CO.sub.3 10.0 0.1048 9.0 10.48 2.50 3.77 1.800 20.00 Com. Ex. 1 PtFeOx/C Non 0.0 0.0000 10.0 0.00 2.50 0.00 0.141 1.41 Com. Ex. 2 PtFeOx/C Non 0.0 0.0000 10.0 0.00 2.50 0.00 0.141 1.41 (NaCl) Com. Ex. 3 PtFeOx/C Non 0.0 0.0000 10.0 0.00 2.50 0.00 0.141 1.41 (Na.sub.2SO.sub.4) Com. Ex. 4 Pt/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 0.113 1.13 Com. Ex. 5 Pt/C Na.sub.2CO.sub.3 5.0 0.0472 10.0 4.72 2.50 1.89 0.113 1.13 Com. Ex. 6 Pt/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 0.567 5.67 Com. Ex. 7 Pt/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 1.123 11.23 Com. Ex. 8 Pt/C Na.sub.2CO.sub.3 10.0 0.0943 10.0 9.43 2.50 3.77 1.123 11.23 Com. Ex. 9 Pt/C Non 0.0 0.0000 10.0 0.00 2.50 0.00 0.113 1.13

TABLE-US-00002 TABLE 2 Selectivity % Selectivity % 5-amino-2- 3-aminopyridine Conversion bromopyridine by-product % main product (DeBr body) Ex. 1 100 90.8 9.2 Ex. 2 100 98.1 1.9 Ex. 3 100 99.5 0.5 Ex. 4 100 99.7 0.3 Ex. 5 100 99.6 0.4 Ex. 6 100 99.6 0.4 Ex. 7 100 98.2 1.8 Ex. 8 100 98.4 1.6 Ex. 9 100 96.0 4.0 Ex. 10 100 92.8 7.2 Ex. 11 100 92.9 7.1 Ex. 12 100 91.3 8.7 Ex. 13 100 94.0 6.0 Ex. 14 100 92.8 7.2 Com. Ex. 1 100 81.5 18.5 Com. Ex. 2 100 79.5 20.5 Com. Ex. 3 100 84.5 15.5 Com. Ex. 4 100 84.7 15.3 Com. Ex. 5 100 72.4 27.6 Com. Ex. 6 100 82.9 17.1 Com. Ex. 7 100 66.5 33.5 Com. Ex. 8 100 42.1 57.9 Com. Ex. 9 100 48.9 51.1

[0129] From the results shown in Table 2, when the reaction system using the catalyst mixtures of Example 1 to Example 14 which satisfies the constitution of the present invention was compared with the reaction system using the catalyst mixtures of Comparative Example 1 to Comparative Example 9, it has been clear that the debromination reaction to 3-aminopyridine represented by the formula (C1-3) was sufficiently reduced, and the selectivity of the desired 5-amino-2-bromopyridine represented by the formula (C1-2) was improved.

[0130] In particular, when the reaction system using the catalyst mixtures of Example 1 to Example 14 which satisfies the constitution of the present invention was compared with the reaction system using the catalyst mixture of Comparative Example 1 which has the structure similar to that of Patent Document 3 described as a prior art document (reaction system which has a catalyst containing a Pt component and an iron oxide component, and does not contain a base), it has been clear that the debromination reaction to 3-aminopyridine represented by the formula (C1-3) was sufficiently reduced.

[0131] Further, when the reaction system using the catalyst mixtures of Example 1 to Example 14 which satisfies the constitution of the present invention was compared with the reaction system using the catalyst mixture of Comparative Example 6 which has the structure similar to that of Patent Document 4 described as a prior art document (reaction system which has a catalyst containing a Pt component, and a base and water is added (in Example 1 of Patent Document 4, 100(Vh/Vs)=100(amount of added water 30 mL+water contained in the catalyst 1.5 mL)/toluene 675 mL=4.6%), it has been clear that the debromination reaction to 3-aminopyridine represented by the formula (C1-3) was sufficiently reduced.

[0132] From the aforementioned results, it has been clear that, in a nitro group hydrogenation reaction of an aromatic nitro compound (aromatic halogen nitro compound) having a structure in which nitro groups and halogen atoms are directly bonded as substituents to a ring skeleton of the same ring while separated from each other, the catalyst mixture of the present examples is capable of selectively hydrogenating the nitro groups and sufficiently reducing the removal of the halogen atoms from the ring.

INDUSTRIAL APPLICABILITY

[0133] The catalyst mixture of the present invention has the catalyst activities that, in a nitro group hydrogenation reaction of an aromatic nitro compound (aromatic halogen nitro compound) having a structure in which nitro groups and halogen atoms are directly bonded as substituents to a ring skeleton of the same ring while separated from each other, is capable of selectively hydrogenating the nitro groups and sufficiently reducing the removal of the halogen atoms from the ring.

[0134] Therefore, the present invention contributes to the development of efficient mass production technology of the aromatic halogen amine which is an important raw material of medicines, dyes, insecticides and herbicides, and further contributes to the development of the industries of pharmaceuticals, dyes, insecticides, herbicides.