JP5605696B2 - Nitrile synthesis catalyst composition and method for producing nitrile using the same - Google Patents

Description

  The present invention relates to a catalyst composition used in an ammoxidation reaction in which a primary alcohol is reacted with ammonia and oxygen to obtain a nitrile, and a method for producing a nitrile using the catalyst composition.

  The corresponding nitrile can be produced by an ammoxidation reaction of alcohol. As an alcohol oxidation catalyst, a catalyst in which noble metal nanoparticles such as palladium are supported on an oxide is generally used. Oxide catalyst systems that do not use noble metals such as molybdenum oxide and vanadium oxide have also been proposed. When such an oxide catalyst is used, it is necessary to use an oxidizing agent such as hydrogen peroxide in combination with oxygen or to perform a high-temperature gas phase reaction. However, when using alcohol with a high boiling point as a raw material, it is difficult to apply gas phase oxidation.

In the ammoxidation reaction in the liquid phase, a noble metal nanoparticle catalyst is used. The use of precious metals is a costly factor. As a synthesis method of nitrile, a composite oxide such as MoO ₃ —Bi ₂ O ₃ —Fe ₂ O ₃ or vanadium oxide is used in the gas phase. As a catalyst for synthesizing nitrile from alcohol in a liquid phase, a noble metal catalyst or nickel sulfate has been reported. However, when nickel sulfate is used, an oxidizing agent is further required.

  Patent Document 1 discloses an ammoxidation reaction of alcohol using a complex oxide without using a noble metal, but is limited to a gas phase reaction. In Non-Patent Document 1, in addition to nickel sulfate as a catalyst, sodium hydroxide is added as an additive, and potassium persulfate is added separately as an oxidant to perform ammoxidation of alcohol without using noble metals in the liquid phase. It is disclosed. Non-Patent Document 2 discloses that an ammoxidation of alcohol is performed without an additive using ruthenium having a small abundance as a noble metal catalyst species.

JP 2002-306968 A JP 2010-17649 A

S. Yamazaki, Y. Yamazaki, Chem. Lett. 1990, 571-574 N. Mizuno, et al., Angew. Chem. Int. Ed. 2009, 48, 6286 Sameer S. Deshpande, Radha V. Jayaram, Catalysis Communications 9 (2008) 186-193 Y. Sasaki, etal., Science and Technology in Catalysis, 1998, 335-338

  In view of the above background art, the present invention provides a catalyst composition capable of obtaining a nitrile without requiring a noble metal or an additional oxidizing agent in an ammoxidation reaction of alcohol in a liquid phase, and It aims at providing the manufacturing method of a nitrile using such a catalyst composition.

As a result of intensive studies by the inventors, the present invention as described below has been completed.
(1) A composition containing at least one metal oxide selected from the group consisting of cobalt oxide, manganese oxide, nickel oxide and palladium oxide, wherein the metal oxide comprises an aqueous solution of a corresponding metal salt and an alkali. It is obtained by mixing an aqueous solution to precipitate a precipitate, and firing the obtained precipitate, and is used as a catalyst in an ammoxidation reaction in which ammonia and oxygen are allowed to act on a primary alcohol to obtain a nitrile. Catalyst composition for nitrile synthesis.
( 2 ) The catalyst composition according to (1 ), wherein the metal oxide has a specific surface area of 10 to 300 m ² / g.
( 3 ) A method for producing a nitrile, in which ammonia and oxygen are allowed to act on a primary alcohol in a liquid phase in the presence of the catalyst composition of (1) or (2) to be subjected to an ammoxidation reaction to synthesize a nitrile.
( 4 ) The production method of ( 3 ), wherein an unsaturated bond is present in the molecular structure of the primary alcohol.
( 5 ) The production method of ( 3 ), wherein a non-conjugated unsaturated bond is present in the molecular structure of the primary alcohol .

  According to the present invention, a nitrile can be synthesized from a primary alcohol by an ammoxidation reaction under relatively mild conditions in a liquid phase, and at this time, an additional oxidation such as a catalyst containing a noble metal, hydrogen peroxide, or the like. The addition of an agent is unnecessary. In the catalyst composition of the present invention, the yield of nitrile is particularly good when the specific surface area is within a specific range. According to the present invention, when the primary alcohol has an unsaturated bond, the oxidation reaction proceeds selectively at the hydroxyl group, so that a nitrile having an unsaturated bond in the main chain or the like can also be efficiently produced. .

One of the features of the present invention is that a specific metal oxide is used as a catalyst.
According to the present invention, at least one metal oxide selected from the group consisting of cobalt oxide, manganese oxide, nickel oxide and palladium oxide is used as a catalyst for nitrile synthesis, preferably manganese oxide. . In the present invention, cobalt oxide, manganese oxide, nickel oxide and palladium oxide may be a composite metal oxide or may be doped with other metal species. Examples of the composite oxide include cobalt-zinc composite oxide containing cobalt, nickel-copper composite oxide, manganese-iron composite oxide, and the like, and metal species that may be doped include zinc, copper, Iron, cerium, potassium and the like can be mentioned, and the metal species which may be mixed or doped are not limited to these. The present inventors have found that the effect of the present invention can be achieved only with a specific metal oxide as a result of many trials and errors with respect to many oxides such as transition metals and other compounds.

  Various metal oxides are available and can be used without any particular limitation. Preferably, an aqueous solution of a corresponding metal salt and an aqueous alkaline solution are mixed to precipitate a precipitate, and the obtained precipitate is fired to obtain the metal oxide. The “corresponding aqueous solution of metal salt” is, for example, an aqueous solution obtained by dissolving a water-soluble salt of cobalt in water when the metal oxide is cobalt oxide. The water-soluble salt is not particularly limited, and may be appropriately selected depending on the type of metal. Examples thereof include nitrates, acetates, hydrochlorides, sulfates, perchlorates and oxalates. be able to.

  By mixing an aqueous solution of a metal salt and an aqueous alkaline solution, for example, an insoluble precipitate (such as a metal hydroxide) can be deposited. What is necessary is just to select the alkali used suitably according to the kind of metal, Specifically, sodium carbonate, sodium hydroxide, sodium hydrogencarbonate, potassium carbonate, potassium hydroxide etc. can be mentioned without limitation. At this time, depending on the type of metal, an oxidizing agent may be used in combination for adjusting the oxidation number. During precipitation of the precipitate, the aqueous solution may be heated to, for example, 40 to 90 ° C.

  The metal oxide can be obtained by collecting and baking the precipitate obtained as described above. Firing conditions can be appropriately selected depending on the type of metal, and are preferably air firing at 200 to 550 ° C, more preferably 250 to 450 ° C. When producing a metal oxide by this method, the specific surface area of the metal oxide particles decreases as the firing temperature increases. By utilizing this fact, the specific surface area of the metal oxide can be controlled to some extent.

When the metal oxide is cobalt oxide, it is usually in the form of Co ₃ O ₄ , and its production method is not particularly limited, and for example, the production method described above can be used. In this case, the starting material is preferably nitrate and the alkali used to obtain a water-insoluble precipitate is preferably sodium carbonate. The recovered precipitate is preferably fired at 200 to 550 ° C. in air.

When the metal oxide is manganese oxide, it is usually in the form of MnO ₂ and its production method is not particularly limited, and for example, it can be according to the production method described above. In this case, the starting material is nitrate, the alkali used to obtain a water-insoluble precipitate is preferably sodium hydroxide, and it is also preferable to use potassium permanganate for adjusting the oxidation number together with the alkali. The recovered precipitate is preferably baked in air at 200 to 650 ° C. Manganese oxide is particularly suitable as a catalyst composition for the present invention, and even manganese oxide having a specific surface area smaller than the preferable specific surface area range described below has excellent catalytic ability.

  When the metal oxide is nickel oxide, it is usually in the form of NiO, and its production method is not particularly limited, and for example, the production method described above can be used. In this case, the starting material is preferably nitrate and the alkali used to obtain a water-insoluble precipitate is preferably sodium carbonate. The recovered precipitate is preferably fired at 200 to 350 ° C, more preferably 250 to 320 ° C.

  When the metal oxide is palladium oxide, it is usually in the form of PdO, and its production method is not particularly limited. For example, the production method described above can be used. In this case, the starting material is preferably acetate and the alkali used to obtain a water-insoluble precipitate is preferably sodium carbonate. The recovered precipitate is preferably baked in air at 280 to 320 ° C.

According to the present invention, the shape of the metal oxide is not particularly limited, and the specific surface area is preferably 10 to 300 m ² / g, and preferably 50 to ²⁰⁰ m ² / g. According to the metal oxide having a specific surface area within the above range, the catalytic ability of the ammoxidation reaction is improved. When preparing a metal oxide by the above-mentioned method, adjustment of a specific surface area can be controlled by a calcination temperature (refer an Example). In the present invention, the value measured by the nitrogen gas adsorption method (the instrument used is Micrometrics Tristar manufactured by Shimadzu Corporation) is adopted as the specific surface area of the metal oxide.

According to the present invention, a corresponding nitrile can be produced by ammoxidation of a primary alcohol using the above-mentioned metal oxide as a catalyst. A primary alcohol represented by the general formula, R—CH ₂ OH (where R is a monovalent organic group), oxygen and ammonia are reacted to form R—CN (where R is a monovalent). It is an ammoxidation reaction to obtain a nitrile represented by an organic group.

According to the present invention, the metal oxide can be used in an independent powder / particulate form, or the metal oxide can be supported on a carrier such as SiO ₂ and used. As a method of supporting the metal oxide on the support, a conventionally known technique may be appropriately used, and examples thereof include a method of sintering in a state where the support and the metal oxide are in contact with each other.

According to the present invention, the primary alcohol to be subjected to ammoxidation is not particularly limited. When expressed by the general formula, R—CH ₂ OH (where R is a monovalent organic group), R preferably has 1 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and still more preferably 4 to 12 carbon atoms. R may have an unsaturated bond in its molecular structure, and this unsaturated bond may be a conjugated unsaturated bond or a non-conjugated unsaturated bond. Also good. In the ammoxidation reaction, there is a concern that undesired oxidation, isomerization, and hydrogenation may occur with respect to the unsaturated bond. However, when the catalyst composition according to the present invention is used, oxidation of the hydroxyl group of the alcohol is selectively performed. Since it easily occurs, the corresponding nitrile can be produced while maintaining the unsaturated bond that may be contained in R. The above-mentioned “hydrogenation” mainly means a case where hydrogenation is performed as a side reaction in the process of alcohol oxidation.

  According to the present invention, the ammoxidation reaction can be performed in a liquid phase. The reaction solvent can be used without particular limitation as long as it can dissolve the primary alcohol to be reacted, and specifically, hydrocarbon solvents (hexane, toluene, Xylene), ethers (THF, dioxane, etc.), halogen-containing solvents such as methanol, ethanol, acetone, chloroform, acetonitrile, DMF, and the like.

  Specific reaction conditions for the ammoxidation reaction can be easily determined with reference to conventional examples. Typically, a primary alcohol to be reacted is dissolved in a solvent and heated in an autoclave in the presence of oxygen gas and ammonia gas, for example, 50 to 200 ° C., preferably 70 to 150 ° C. The reaction can be advanced by, for example.

  The primary alcohol concentration may be set at an arbitrary ratio, for example, 0.1 to 3M, and preferably 0.1 to 1M. The gas partial pressures of oxygen and ammonia are not particularly limited and may be set so as to avoid the explosion range, and an inert gas such as nitrogen may be added as necessary. The ammonia gas only needs to be 1 equivalent or more with respect to the primary alcohol of the substrate, and the oxygen gas may not be present, but preferably 1 equivalent or more, more preferably 2 equivalents or more. In addition, about 20% of the reaction proceeds with ammonia alone without adding oxygen, and nitrile is produced. This is thought to be because dehydrogenation, not oxidation, occurs in part in the reaction from alcohol to aldehyde and in each stage where imine generated from aldehyde and ammonia becomes nitrile.

  Examples according to the present invention will be described below. However, the present invention is not limited to the embodiments described in these examples.

[Examples 1 to 3] Preparation of cobalt oxide (Co ₃ O ₄ ) 5.9 g (20 mmol) of cobalt nitrate (Co (NO ₃ ) ₂ · 6H ₂ O) was dissolved in 200 mL of distilled water, and this was prepared in advance. It was added to 250 mL of an aqueous 0.1 M Na ₂ CO ₃ solution at 70 ° C. The obtained mixed solution was stirred at 70 ° C. for 1 hour and then allowed to stand, and the precipitate was washed with distilled water until the pH of the supernatant was stabilized. After collecting the precipitate by suction filtration and drying it at 65 ° C., each example was calcined with air at different temperatures shown in Table 1 for 4 hours to obtain a catalyst composition comprising cobalt oxide.

Was dissolved Example 4-9] manganese nitrate Preparation 86.1g of manganese oxide _{(MnO 2) (0.3mol) (} Mn (NO 3) 2 · 6H 2 O) in distilled water 500 mL. In another container, 31.6 g (0.2 mol) of potassium permanganate (KMnO ₄ ) and 24.0 g (0.6 mol) of sodium hydroxide were dissolved in 500 mL of distilled water. This aqueous potassium permanganate solution was added to the previous aqueous manganese nitrate solution and stirred at room temperature for 1 hour. After standing, the precipitate was washed with distilled water until the pH of the supernatant was stabilized. After collecting the precipitate by suction filtration and drying it at 65 ° C., each example was calcined with air at different temperatures shown in Table 1 for 4 hours to obtain a target catalyst composition comprising manganese oxide.

[Examples 10 to 11] Preparation of nickel oxide (NiO) 5.9 g (10 mmol) of nickel nitrate (Ni (NO ₃ ) ₂ · 6H ₂ O) was dissolved in 200 mL of distilled water, and this was prepared in advance. Was added to 250 mL of 0.1 M Na ₂ CO ₃ aqueous solution at 70 ° C. The obtained mixed solution was stirred at 70 ° C. for 1 hour and then allowed to stand, and the precipitate was washed with distilled water until the pH of the supernatant was stabilized. After collecting the precipitate by suction filtration and drying it at 65 ° C., each example was calcined with air at different temperatures shown in Table 1 for 4 hours to obtain a catalyst composition comprising nickel oxide.

Experimental Example 12] The distilled water 10mL acetone 30mL was added to _Pd (CH 3 _{COO) 2} Preparation 1.54g of palladium oxide (PdO), and stirred for 1 hour at 70 ° C.. This solution was added to a stoichiometric amount of 2 equivalents of an aqueous Na ₂ CO ₃ solution (70 ° C.) and stirred for 1 hour. The resulting precipitate was washed with distilled water at 40 ° C. until the pH was stabilized, recovered by suction filtration, dried at 65 ° C., and then air calcined at 300 ° C. for 4 hours to form a catalyst composition comprising palladium oxide. I got a thing.

[Evaluation of catalytic ability 1] Synthesis of benzonitrile by ammoxidation of benzyl alcohol Ammoxidation of benzyl alcohol was carried out using the catalyst composition prepared in each Example. 52 μL (0.5 mmol) of benzyl alcohol, 0.02 g of the catalyst composition, 3 mL of dehydrated toluene and a magnetic stir bar were placed in the autoclave. Ammonia gas and oxygen gas were charged at a partial pressure of 0.85 MPa and 0.5 MPa, respectively, and stirred at 100 ° C. for 4 hours (in the case of manganese oxide, 0.5 hour). The conversion and yield for the formation of benzonitrile were measured by gas chromatography analysis. The results are summarized in Table 1.

[Evaluation of catalytic ability 2] Solvents other than toluene in ammoxidation For the catalysts of Examples 1 to 3, an ammoxidation reaction was attempted using 1,4-dioxane, THF and methanol as solvents instead of toluene. Could be manufactured.

[Evaluation of catalytic ability 3]
When the catalysts of Examples 4 to 9 were subjected to an ammoxidation reaction using cinnamyl alcohol and octanol instead of benzyl alcohol, the corresponding nitrile could be produced. Cinnamyl alcohol has a non-conjugated unsaturated double bond in the chain skeleton, but the unsaturated double bond is not oxidized, hydrogenated or isomerized, but only the hydroxyl group of the alcohol is selective. Oxidized.

[Comparative example]
Ammoxidation was attempted by the same operation as described above using the oxides listed below, but the reaction did not proceed and nitrile could not be obtained.
Fe ₂ O ₃ , CuO, SiO ₂ , Al ₂ O ₃ (specific surface area 285 m ² / g), V ₂ O ₅ (specific surface area 4 m ² / g), TiO ₂ (specific surface area 50 m ² / g), CeO ₂ ( Specific surface area 166 m ² / g), ZrO ₂ (specific surface area 80-120 m ² / g), Nb ₂ O ₅ (specific surface area 5 m ² / g), Y ₂ O ₃ , MoO ₃

  According to the present invention, a nitrile can be produced from a primary alcohol under relatively mild conditions, and particularly useful in that a nitrile having an unsaturated bond in the molecular structure can be selectively produced. is there.

Claims (5)

A composition containing at least one metal oxide selected from the group consisting of cobalt oxide, manganese oxide, nickel oxide and palladium oxide ,
The metal oxide is obtained by mixing an aqueous solution of a corresponding metal salt and an aqueous alkali solution to precipitate a precipitate, and firing the obtained precipitate .
Used as a catalyst in an ammoxidation reaction in which ammonia and oxygen are allowed to act on a primary alcohol to obtain a nitrile,
Catalyst composition for nitrile synthesis. The metal oxide according to claim 1 Symbol placement of the catalyst composition having a specific surface area of 10 to 300 m ² / g of. Presence of claim 1 or 2 SL placing the catalyst composition, by the action of ammonia and oxygen to a primary alcohol in the liquid phase to synthesize a nitrile is subjected to ammoxidation method nitrile. The process according to claim 3 , wherein an unsaturated bond is present in the molecular structure of the primary alcohol. The production method according to claim 3 , wherein a non-conjugated unsaturated bond is present in the molecular structure of the primary alcohol .