JP2851667B2 - Alcohol production - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for producing alcohol, and more particularly, to a method for hydrogenating an organic carboxylic acid ester using a highly durable catalyst and producing a corresponding alcohol at a high yield. And a method for manufacturing with high selectivity.

[Conventional technology and its problems]

Many methods for producing an aliphatic alcohol, an alicyclic alcohol or an aromatic alcohol by hydrogenating a carboxylic acid or a carboxylic acid ester have been disclosed since the 1930s. However, most of the methods for hydrogenating a carboxylic acid ester to industrially produce the corresponding alcohol use a copper-chromium catalyst under high-temperature and high-pressure reaction conditions. This is a disadvantage in terms of the use of chromium, as well as an economic disadvantage due to severe reaction conditions, and the development of a chromium-free catalyst to replace the copper-chromium-based catalyst has been called for. I have.

Some attempts have been made to obtain a corresponding alcohol by hydrogenating a carboxylic acid ester using a copper-zinc composite oxide catalyst as a catalyst instead of the copper-chromium-based catalyst. Oxide catalysts are generally inferior to copper-chromium catalysts in poisoning by trace impurities in the raw material ester or in thermal stability of the catalyst, and are insufficient in catalyst durability.

[Means for solving the problem]

In view of the above, the present inventors diligently seek to find a copper-zinc composite oxide catalyst that maintains a practical reaction rate and has high catalyst durability in a method for hydrogenating a carboxylic acid ester to produce a corresponding alcohol. As a result of research,
The following catalyst was found to be suitable for the purpose.

That is, the following formula (I) (I) [CuO] _a [ZnO] _b [AO] _c [BO] _d AO: WO ₃ and / or MoO ₃ BO: at least one selected from alkali metals and alkaline earth metals Metal oxides a, b, c, d: weight% of each component a / b = 80/20 to 100/0 (weight ratio) c: 0.1 to 20% by weight d: composite represented by 0 to 20% by weight Metal oxide (I) is converted to titanium oxide and / or
Or (I) / (II) (weight ratio) =
The catalyst obtained by reducing the catalyst precursor supported or contained at a ratio of 15/85 to 75/25 is insufficient with the conventionally known copper-zinc catalyst, due to trace impurities in the raw material ester. The present inventors have obtained a result of having a high degree of durability while maintaining a practical reaction rate against poisoning or thermal deterioration of the catalyst, and completed the present invention.

That is, the present invention relates to a method in which the composite metal oxide (I) is added to the titanium oxide and / or hydroxide carrier (II) by using (I) / (II)
(Weight ratio) = 15/85 to 75/25 in the presence of a catalyst obtained by reducing a catalyst precursor supported or contained at a ratio of
It is intended to provide a method for producing an alcohol, which comprises catalytically reducing an organic carboxylic acid ester with hydrogen.

Several attempts have been made to improve catalyst durability by adding a third metal component to a copper-zinc composite oxide catalyst. For example, [Industrial Chemistry Magazine, Vol. 53, 74
Page (1950)] reports that in the hydrogenation reaction of sperm whale skin oil, the durability of the catalyst was improved by adding a small amount of chromium oxide to a copper oxide-zinc oxide catalyst supported on diatomaceous earth. However, in this case, the use of chromium is practically disadvantageous. JP-A-53-133594 states that in the hydrogenation reaction of polyglycolate to ethylene glycol, the coprecipitated cobalt-zinc-copper oxide catalyst is superior to the coprecipitated copper-zinc oxide catalyst in stability. As mentioned, high activity has not been obtained despite the use of large amounts of catalyst. Also, Japanese Patent Laid-Open No. 54-
In Japanese Patent No. 32191, the hydrogenation reaction of coconut fatty acid methyl ester is carried out using a copper oxide-copper molybdate-zinc oxide catalyst. No mention is made of catalyst durability.

Further, the present inventors have previously prepared (A) copper oxide or a composite metal oxide composed of copper oxide and zinc oxide (copper oxide / zinc oxide (weight ratio) = 100/0 to 80/20) and (B) titanium (A) / (B) (weight ratio) = 15/8 on oxide and / or hydroxide carrier
A catalyst obtained by reducing a catalyst precursor supported at a ratio of 5 to 65/35 has been proposed (Japanese Patent Application Laid-Open No. 1-305042).

However, in any of the above production methods, in the method of hydrogenating a fatty acid ester and producing a corresponding aliphatic alcohol, a practical method is used for poisoning by trace impurities in the raw material ester or thermal degradation of the catalyst. Until now, there has been no known example in which a copper-zinc composite oxide catalyst having a high reaction rate and high durability has been found.

In the present invention, the catalyst composition is very important. That is,
The following formula (I) before reduction activation: (I) [CuO] _a [ZnO] _b [AO] _c [BO] _d AO: WO ₃ and / or MoO ₃ BO: selected from alkali metals and alkaline earth metals In the composite metal oxide (I) represented by one or more metal oxides, copper oxide (Cu
O) and zinc oxide (ZnO) have a weight ratio of 80/20 to 100/0, preferably 90/10 to 98/2, and the composite metal oxide (I) contains tungsten oxide (WO ₃ ) and molybdenum oxide. 0.1-20% by weight of one or more metal oxides selected from (MoO ₃ )
Preferably, it is essential to contain 0.5 to 10% by weight. Here, as the fourth component, an oxide of one or more metals selected from alkali metals and alkaline earth metals may be contained in an amount of up to 20% by weight. Alkali metals and alkaline earth metals include Na, Li, K, Rb, Cs, Be, Mg, Ca, S
r and Ba are mentioned.

Further, the composite metal oxide (I) and titanium oxide and / or
Alternatively, in the catalyst precursor before reduction activation composed of the hydroxide carrier (II), the weight ratio of the composite metal oxide component represented by (I) / (II) to the carrier component is 15/85 to 75 / It is important to be in the range of 25, preferably 30 / 70-60 / 40.

In the present invention, if the component composition is within the above range, a simple mixture of the components (I) and (II) is effective as a catalyst (catalyst precursor). More preferably, the component (I) is carried on the component (II).

The method for producing the catalyst precursor composition according to the present invention is not particularly limited, and is prepared by a known method. For example, a precipitant is added to a mixed aqueous solution containing each metal salt, or in the presence of a carrier component, titanium oxide and / or hydroxide,
A method in which a precipitate obtained by adding a precipitant to an aqueous solution of a metal salt that can be a catalyst component other than the carrier component is washed with water, dried and calcined (coprecipitation method), or titanium oxide and / or hydroxide as the carrier component After impregnating and supporting a metal salt that can be a catalyst component other than the carrier component from an aqueous solution state,
It is prepared by a method of baking (impregnation method) or a method of uniformly kneading a metal compound that can be a catalyst component, followed by baking (uniform kneading method). The above preparation methods may be used in combination as needed. For example, as shown in Examples of the present invention, a compound of copper and zinc is supported on titanium oxide (TiO ₂ ) as a carrier component by a coprecipitation method, washed with water and dried, and then a compound containing other components is added. The catalyst precursor may be prepared by adding by an impregnation method or a uniform kneading method, followed by drying and calcining.

When the catalyst precursor is prepared by the coprecipitation method or the impregnation method, any metal salt can be used as long as it is water-soluble, but generally, nitrate, sulfate, ammonium complex, acetate and the like can be used. Salts, acetylacetonate salts and chlorides are used.

Further, as the water-soluble salts of tungstate compounds and molybdate compounds, ammonium salts such as ammonium paratungstate and ammonium paramolybdate can be used in addition to alkali metal salts such as sodium salts and potassium salts.

As a precipitant used in the coprecipitation method, an aqueous alkali solution such as ammonia, urea, ammonium carbonate, sodium carbonate, sodium hydrogencarbonate, sodium hydroxide, or potassium hydroxide is used. The precipitation pH is preferably from 2 to 11.

In the homogeneous kneading method, a metal compound insoluble in water is selected, and generally, an oxide, a hydroxide, a carbonate, or the like is used.

Examples of the titanium oxide and / or hydroxide used in the present invention include TiO ₂ (titania), TiO, titanium oxide such as Ti ₂ O ₃ , metatitanic acid (TiO (OH) ₂ ), and titanic acid (Ti (OH) ₄ )
Alternatively, a mixture thereof is mentioned, and the higher the surface area, the better. These carriers are also prepared by the hydrolysis of chlorides, oxalates and alkoxides, or by precipitation from aqueous sulfate.

The firing is desirably performed in a temperature range of 300 to 600 ° C., and the firing may be performed after the granulation molding as described below.

As the granulation molding method, a general granulation method such as compression granulation, extrusion granulation, and tumbling granulation can be applied.
Known molding aids may be used to improve strength, wear resistance, and the like. Known molding aids include clay, cement, water glass, starch, cellulose, thermosetting resin, polyvinyl alcohol, polyethylene glycol, graphite,
Fatty acid salts and the like. It is usually desirable that the addition amount of these molding aids is 0.1 to 10% by weight based on the catalyst precursor.

Next, when hydrogenating the carboxylic acid ester, reduction activation of the catalyst precursor is required. When the catalyst precursor is activated by reduction, any of a gas phase reduction method and a liquid phase reduction method performed in a solvent such as hydrocarbon such as liquid paraffin, dioxane, aliphatic alcohol or fatty acid ester may be used. For example, when reducing using hydrogen gas,
It is desirable to carry out the reaction at a temperature of 100 to 800 ° C., preferably 150 to 500 ° C., until water formation is no longer observed or hydrogen absorption is no longer observed. In particular, when the reduction is carried out in a solvent, it is desirable to carry out the reduction at a temperature of 150 to 350 ° C. until hydrogen absorption is no longer observed. Further, in the ester which is a hydrogenation raw material, the catalyst precursor is
There is no problem even if a normal activation method in which the temperature is raised, reduced, and used for the reaction as it is is used.

As a reducing agent used for reducing the catalyst precursor, there are carbon monoxide, ammonia, hydrazine, formaldehyde and lower alcohols such as methanol in addition to the above-mentioned hydrogen, and these reducing agents are used alone or in a mixed state. You may. Also, nitrogen, helium,
It may be used in a state diluted with an inert gas such as argon or in the presence of a small amount of water vapor.

Examples of the carboxylic acid ester subjected to the hydrogenation reaction using the catalyst obtained from the catalyst precursor of the present invention include lower or higher alcohol esters of alicyclic carboxylic acids, aromatic carboxylic acids and aliphatic carboxylic acids. In these, the carboxylic acid moiety is reduced by hydrogenation to form the corresponding alcohol. For example, an ester of a straight-chain or branched-chain saturated or unsaturated fatty acid having 1 or more carbon atoms and an alcohol, and an ester of an alicyclic carboxylic acid or an aromatic carboxylic acid and an alcohol are exemplified. The alcohol portion constituting the carboxylic acid ester is not particularly limited. Examples of such carboxylic esters include formate, acetate, caproate, caprylate, undecenoate, laurate, myristate, palmitate, stearate, isostearate, and oleate. Oxalate, maleate, adipate, sebacate, cyclohexanecarboxylate, benzoate, phthalate and the like.

In hydrogenating the carboxylic acid ester, any one of a suspension bed reaction system, a fixed bed reaction system, and a fluidized bed reaction system is employed depending on the shape of the catalyst.

For example, when a suspension bed reaction method is employed, a solvent can be used for the reaction, but it is desirable to carry out the reaction without a solvent in consideration of productivity. As the solvent,
Those which do not adversely affect the reaction such as alcohol, dioxane or hydrocarbon are selected. In this case, the amount of the catalyst is preferably 0.1 to 20% by weight based on the carboxylic acid ester, but can be arbitrarily selected according to the reaction temperature or the reaction pressure within a range where a practical reaction rate can be obtained. The reaction temperature is from 160 to 350 ° C, preferably from 180 to 280 ° C. The reaction pressure is 1 to 350 kg / cm ² , preferably 30 to 300 kg / cm ² .

When a fixed bed reaction system is adopted, a catalyst which is shaped for a purpose is used. The reaction temperature is 130-300 ° C,
Preferably it is 160 to 270 ° C. The reaction pressure is between 0.1 and 300 kg / cm ² . Here, the liquid hourly space velocity (LHSV) is arbitrarily determined according to the reaction conditions, but is preferably in the range of 0.5 to 5 in consideration of productivity or reactivity.

〔The invention's effect〕

By using the highly durable catalyst obtained in the present invention, the corresponding alcohol can be produced in a high yield and a high selectivity by catalytically reducing the organic carboxylic acid ester with hydrogen at a practical reaction rate over a long period of time. . Further, since the catalyst used in the present invention does not contain harmful metals such as chromium, the safety to human bodies and the environment is high.

〔Example〕

Hereinafter, the present invention will be described in more detail by examples,
The present invention is not limited to these examples.

<Preparation of catalyst precursor> Preparation Example 1 Titanium oxide (anatase type) produced from titanium sulfate
And a mixed aqueous solution of copper nitrate and zinc nitrate and a 10% by weight aqueous solution of sodium carbonate are stirred and mixed at 98 ° C.
Was obtained as a slurry. The precipitate was separated from this slurry by filtration, washed sufficiently with water, and dried at 110 ° C. for 12 hours to obtain a titanium oxide-supported copper oxide-zinc oxide composite oxide.

The composite oxide thus obtained was represented by the following weight composition.

CuO: ZnO: TiO ₂ = 38%: 2%: 60% (95.0%: 5.0%) However, the weight composition of copper oxide and zinc oxide is shown in parentheses.

Next, 150g of 2.3g of sodium tungstate dihydrate
After kneading an aqueous solution dissolved in distilled water and 200 g by weight of the precipitated cake after drying in a kneader for 1 hour,
Further drying was performed at 110 ° C. for 12 hours. To the titanium oxide-supported copper oxide-zinc oxide-sodium tungstate composite metal oxide powder after drying, magnesium stearate was added as a lubricant at 2% by weight based on the powder, mixed well, and height was adjusted by a rotary tableting machine. It was formed into a pellet having a diameter of 3 mm and a diameter of 3 mm.

The obtained pellet was calcined at 450 ° C. for 2 hours to obtain a catalyst precursor. The content of tungsten oxide (WO ₃ ) in the composite metal oxide excluding the carrier, titanium oxide, was 2.0% by weight by atomic absorption analysis. Let the obtained catalyst precursor be A.

Preparation Examples 2, 3 According to the method described in Preparation Example 1, the amount of tungsten oxide (WO ₃ ) in the composite metal oxide was 4.8% by weight and 9.3% by weight, respectively, by changing only the addition amount of sodium tungstate. Were prepared and designated B and C, respectively.

Preparation Examples 4 to 7 Instead of sodium tungstate of Preparation Example 1, calcium tungstate (CaWO ₄ ), barium tungstate (BaWO ₄ ), and zinc tungstate (ZnW) were separately prepared.
O ₄ ) and copper tungstate (CuWO ₄ ) were used to prepare catalyst precursors according to the method described in Preparation Example 1, and these were designated as D, E, F, and G, respectively.

Preparation Examples 8 and 9 A catalyst precursor was prepared according to the method described in Preparation Example 1 using sodium molybdate (Na ₂ MoO ₄ ) and ammonium molybdate ((NH ₄ ) ₂ MoO ₄ ) instead of sodium tungstate of Preparation Example 1. The bodies were prepared and designated H and I, respectively.

Preparation Example 10 A catalyst precursor was prepared according to the method described in JP-A-1-305042.

That is, the catalyst was prepared according to the method described in Preparation Example 1 without adding sodium tungstate to obtain a catalyst precursor J.

Preparation Example 11 A catalyst was prepared in the same manner as in Preparation Example 1 except that titanium oxide and sodium tungstate were not added, and a known catalyst precursor K prepared by a conventional technique was obtained.

The catalyst precursor K thus obtained had the following weight composition.

CuO: ZnO = 60%: 40% Examples 1 to 9 and Comparative Examples 1 and 2 The catalyst precursors A to K prepared above were reduced and activated to obtain catalysts, and alcohols were produced using them. The following catalyst durability test was carried out for the catalyst (1).

<Catalyst durability test> 15 g of the catalyst precursor prepared in Preparation Examples 1 to 11 was charged into an autoclave-type basket reactor together with 200 g of lauryl alcohol, and hydrogen pressure was 10 kg / cm ² (gauge pressure), temperature was 200 ° C, and hydrogen was flowing. For 2 hours to activate the reduction of the catalyst precursor.

After reduction, lauryl alcohol was replaced with 200 g of fatty acid methyl ester (saponification value (SV) = 250) and hydrogen pressure was 230 kg / c.
The reaction was carried out for 3 hours under hydrogen flow with m ² (gauge pressure), temperature 250 ° C., stirring speed 900 rpm, and the first-order reaction rate constant was calculated from SV over time.

After completion of the reaction, the generated alcohol was removed, and the entire amount of the recovered catalyst was used.
The hydrogenation reaction of the fatty acid methyl ester was repeated 10 times, and each first-order reaction rate constant was calculated.

The first-order reaction rate constant was plotted against the number of reactions, and the slope of the linear portion was expressed as the rate of decrease with respect to the initial activity per reaction, to determine the rate of decrease in catalyst activity.

 Table 1 shows the obtained results.

Results It can be seen that the catalyst used in the present invention has extremely excellent activity even at the tenth reaction.

Continuation of the front page (56) References JP-A-1-305042 (JP, A) JP-A-54-32191 (JP, A) JP-A-2-36135 (JP, A) (58) Fields investigated (Int .Cl. ⁶ , DB name) C07C 29/149

Claims (1)

(57) [Claims] 1. The following formula (I): (I) [CuO] _a [ZnO] _b [AO] _c [BO] _d AO: WO ₃ and / or MoO ₃ BO: selected from alkali metals and alkaline earth metals Oxide of one or more metals a, b, c, d: weight% of each component a / b = 80 / 20-100 / 0 (weight ratio) c: 0.1-20 weight% d: 0-20 weight% Is converted to titanium oxide and / or
Or (I) / (II) (weight ratio) =
A method for producing an alcohol, comprising catalytically reducing an organic carboxylic acid ester with hydrogen in the presence of a catalyst obtained by reducing a catalyst precursor supported or contained at a ratio of 15/85 to 75/25.