JP2004033985A - Method for producing molybdenum carrying sponge metal catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a molybdenum carrying sponge metal catalyst which is costwise advantageous and suppresses damage to the environment to the minimum. <P>SOLUTION: In the method for producing a molybdenum carrying sponge metal catalyst by bringing an aqueous solution containing molybdic acid and/or a molybdate into contact with a sponge metal catalyst, water containing an alkaline earth metal salt and/or an alkaline earth metal chloride is brought into contact with the sponge metal catalyst and then the aqueous solution containing the molybdic acid and/or the molybdate is brought into contact with the sponge metal catalyst at pH 4-12. <P>COPYRIGHT: (C)2004,JPO

Description

【００４０】
表１に示した結果から明らかなように、実施例１と比較例１を比較した場合、実施例１では塩化マグネシウムで前処理したため、触媒に対するモリブデン担持効率が極めて多くなり、触媒に担持されたモリブデン量が多くなった結果として排水中のモリブデン含量が低減されている。
【００４１】
また、本発明方法で得られた実施例１の触媒は同じモリブデン担持量に調整された合金より調整した比較例１、２のモリブデン担持スポンジ金属触媒より、グルコースの水素添加反応に対して優れた触媒活性を有している。
【００４２】
【発明の効果】
本発明方法により、スポンジ金属触媒として有用なモリブデン担持スポンジ金属触媒をコスト的に有利にかつ環境に対するダメージを最小限に押さえて製造することができる。
【００４３】
また、本発明により製造したモリブデン担持スポンジ触媒は、水素添加触媒または脱水素触媒として有用である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a molybdenum-supported sponge metal catalyst useful as a sponge metal catalyst in a cost-effective manner while minimizing damage to the environment, and a hydrogenation catalyst for a molybdenum-supported catalyst produced by the production method. Alternatively, it relates to utilization as a dehydrogenation catalyst.
[0002]
[Prior art]
The sponge metal catalyst is a general term for a catalyst composed of a metal having an active surface, which is conventionally called a Raney metal catalyst. More details are described in Teruo Kubo, Shinichiro Komatsu, "Raney Catalyst", Kyoritsu Shuppan (1971). The sponge metal catalyst is usually a metal having a catalytic action (hereinafter abbreviated as “metal A”), for example, a metal eluted with nickel, cobalt, copper, iron, silver, palladium, etc. (hereinafter referred to as “metal B”). For example, a sponge-like material obtained by eluting a metal eluted by an erosion agent such as water, alkali, acid or the like from an alloy of aluminum, silicon, zinc, and magnesium (hereinafter, abbreviated as “development step”). It is a catalyst mainly composed of active metal in the form.
[0003]
These sponge metal catalysts usually have a catalytic activity to remarkably exhibit their catalytic properties, for example, a combination of nickel, cobalt, copper, iron, silver, and palladium, or a multi-metal by mixing a small amount of another metal. Many sponge metal catalysts have been reported.
[0004]
Molybdenum-supported sponge metal catalysts are useful catalysts for the hydrogenation of hydroxyl-containing carbonyl groups, and are widely used in the production of mannitol and sorbitol from saccharides. is there.
[0005]
The most useful method of obtaining a multi-component sponge metal catalyst such as a molybdenum-supported sponge metal catalyst is to prepare an alloy of a metal A having a catalytic action and a metal B to be added with a metal eluted, and then through a development step This is a method for obtaining a multi-component sponge metal catalyst. That is, as a method for obtaining a molybdenum-containing sponge metal catalyst, for example, in the case of a molybdenum-containing developed sponge nickel catalyst, it is obtained by preparing a nickel-aluminum-molybdenum alloy and removing aluminum by an alkali treatment in the developing step.
[0006]
However, in this method, a phenomenon occurs in which molybdenum is eluted together with aluminum during alkali treatment.
[0007]
According to the study of the present inventors, the molybdenum residual ratio in the catalyst when the alloy of Ni: 40 to 50% by weight, Al: 60 to 50% by weight, and Mo: 3% by weight is treated with an alkali is 10 to 30%. Yes, more than half are eluted and mixed into wastewater.
[0008]
For this reason, in order to produce a molybdenum-supported sponge nickel catalyst having a high molybdenum-supporting rate, it is necessary to increase the molybdenum ratio of the alloy, which has the disadvantage of increasing the production cost of the catalyst. In addition, molybdenum is eluted during the alkali treatment, so that molybdenum is mixed into the wastewater, which has a problem in terms of waste liquid treatment, that is, environmental load.
[0009]
Japanese Patent Application Laid-Open No. 55-15692 discloses a method for adjusting a molybdenum-containing sponge nickel catalyst by bringing a molybdenum compound into contact with a sponge metal catalyst. It is also described that a molybdenum-containing sponge nickel catalyst obtained by contacting a molybdenum compound with a sponge nickel catalyst has higher activity than a molybdenum-containing sponge nickel catalyst. Although a molybdenum-supported sponge metal catalyst can be obtained more efficiently than a conventional preparation of a multi-component sponge metal catalyst by developing a multi-component alloy, the same report does not solve the problem relating to waste liquid.
[0010]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to solve these conventional problems and to provide a manufacturing method which is advantageous in terms of cost and minimizes damage to the environment.
[0011]
[Means for Solving the Problems]
The present inventors have conducted intensive studies on obtaining a high molybdenum-containing sponge metal catalyst. As a result, after sponge metallization from an alloy (hereinafter referred to as “development”), molybdenum and / or molybdate are converted to a specific pH range. It has been found that the above-mentioned problem can be solved by the addition, and the present invention has been accomplished.
[0012]
That is, the present invention
(1) A method for producing a molybdenum-supported sponge metal catalyst by bringing an aqueous solution containing molybdic acid and / or molybdate into contact with a sponge metal catalyst, comprising an alkaline earth metal salt and / or an alkaline earth metal chloride. A method for producing a molybdenum-supported sponge metal catalyst, comprising: bringing a sponge metal catalyst into contact with an aqueous solution containing molybdic acid and / or molybdate at pH 4 to 12 after contacting the sponge metal catalyst with water.
(2) A hydrogenation catalyst comprising a molybdenum-supported sponge catalyst obtained by the method described in (1).
(3) A dehydrogenation catalyst comprising a molybdenum-supported sponge catalyst obtained by the method described in (1).
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
The method for producing a molybdenum-supported sponge catalyst of the present invention uses a conventional technique to develop an alloy of a metal having catalytic activity and a metal to be eluted, and to prepare a sponge metal catalyst containing a target active metal species. Is carried out. The sponge catalyst in the present invention is obtained by developing an alloy for a sponge metal, and is a sample before a molybdenum supporting step is performed.
[0014]
Examples of the sponge metal alloy of the present invention include a binary alloy selected from one of a metal having catalytic activity and an eluting metal and a multi-element alloy selected from two or more of a metal having catalytic activity and an eluting metal. be able to.
[0015]
Examples of the metal having catalytic activity include nickel, cobalt, copper, iron, silver, and palladium, and nickel, cobalt, and copper are more preferable in terms of cost.
[0016]
Examples of the eluting metal include aluminum, silicon, zinc, magnesium and the like, and aluminum is selected because it is easy to elute and is inexpensive.
[0017]
Specifically, a Ni-Al alloy, a Co-Al alloy, and a Cu-Al alloy are mentioned. Examples of the multi-element alloy include an Fe-Ni-Al alloy.
[0018]
Naturally, there is no problem in the process even if a sponge metal developed from a conventional molybdenum-containing multi-element alloy such as a Mo-Ni-Al alloy is used in the production method of the present invention, but the molybdenum which is a feature of the present invention is not affected. The effect of reducing the contained waste liquid is inconsistent with the effect, which is not preferable.
[0019]
The sponge metal catalyst-containing slurry immediately after the development shows alkalinity exceeding pH 12, because the eluted alkali remains. This is adjusted to a pH below 12 by decantation.
[0020]
At this time, the amount of water used can be significantly reduced by adding an acid to the water used for decantation.
[0021]
Examples of acids to be added include hydrochloric acid, sulfuric acid, nitric acid, boric acid and the like as inorganic acids, and formic acid and acetic acid as organic acids. Phosphoric acids that are commonly used for pH adjustment are not preferred because they combine with molybdenum in an aqueous solution to be added later and color.
[0022]
The sponge metal catalyst-containing slurry adjusted to a pH of less than 12 by decantation is brought into contact with an alkaline earth metal-containing water to which an alkaline earth metal salt and / or an alkaline earth metal chloride has been added to carry out pretreatment of molybdenum loading.
[0023]
Preferable examples of the alkaline earth metal salt and the alkaline earth metal chloride include magnesium sulfate, magnesium chloride, calcium chloride and barium chloride. Magnesium chloride and calcium chloride are preferable in terms of economy.
[0024]
By the contact of the alkaline earth metal salt and / or the alkaline earth chloride-containing water, the molybdenum loading on the sponge metal catalyst in the next step proceeds smoothly, and the molybdic acid and / or molybdate added in the next step is removed. The loading ratio increases, and the amount of molybdenum in the waste liquid becomes extremely small, thereby producing the effect of the present invention.
[0025]
At this time, the amount of the alkaline earth metal salt and / or the alkaline earth metal chloride to be brought into contact is 100 to 10000 ppm with respect to the metal mass of the sponge metal catalyst. According to the study of the present inventors, 10,000 ppm or less of alkaline earth metal salt and / or alkaline earth metal chloride is adsorbed almost quantitatively on the surface of the sponge metal catalyst adjusted to pH less than 12, and the molybdate in the next step Contributes to the adsorption of If the contact amount is less than 100 ppm with respect to the metal mass of the sponge metal catalyst, it is not preferable because there is no effect of increasing the molybdate adsorption efficiency in the next step. There is no problem even if the contact exceeds 10,000 ppm, but the effect of increasing the molybdic acid adsorption efficiency in the next step has reached a plateau and is not required. The alkaline earth metal salt and / or alkaline earth metal chloride is preferably brought into contact with an aqueous sponge metal catalyst having a concentration of about 14 to 1400 ppm, more preferably 50 to 300 ppm.
[0026]
When the aqueous solution containing molybdic acid and / or molybdate is brought into contact with the sponge metal catalyst, the pH of the aqueous solution is 4.0 to 12, preferably 5.0 to 10.0. If the pH is lower than this, the catalyst dissolves, which is not preferable. If the pH is higher than this, the loading ratio of molybdic acid and molybdate decreases, which is not preferable. More specifically, the pH of the aqueous solution when the aqueous solution containing molybdic acid and molybdate is brought into contact with the sponge metal catalyst affects the amount of molybdenum supported on the sponge metal catalyst. At a pH of 9 to 12, the amount of molybdenum supported on the order of 0.5 to 0.7% based on the weight of the sponge metal catalyst reaches a plateau. When the pH is 9 or less, molybdenum can be supported by 1.0% or more based on the weight of the sponge metal catalyst.
The contacting temperature at this time is preferably from 10C to 100C. When the contact temperature is lower than 10 ° C., the adsorption rate is low, and when the contact temperature is higher than 100 ° C., the activity decreases, which is not preferable.
[0028]
The molybdate added in the present invention includes alkali metal salts of molybdic acid such as sodium and potassium, alkaline earth metal salts such as Mg, Ca, and Ba, ammonium salts, phosphomolybdates, and molybdates. However, alkali metal salts are preferred from the viewpoint of handling.
[0029]
In the present invention, the contact amount of molybdic acid and / or molybdate is 0.1 to 10% by weight, preferably 0.3 to 5.0% by weight, based on the maximum content of metal contained in the sponge metal catalyst. Is preferred. When the amount is less than 0.1%, the amount of molybdenum supported is small, and even when the contact is performed in excess of 10% by weight, no increase in the amount of molybdenum with respect to the contact amount is observed. Since it remains, it is not preferable in terms of environmental load.
[0030]
Further, when an aqueous solution containing molybdic acid and / or molybdate is brought into contact with the sponge metal catalyst, the concentration of molybdate and molybdate in the aqueous solution to be contacted is preferably 0.05 to 1.0%.
[0031]
The molybdenum-supported sponge metal catalyst according to the production method of the present invention can be used in the same manner as a usual sponge metal catalyst. For example, in the case of a hydrogenation reaction, although depending on the substrate, a molybdenum-supported sponge metal catalyst is added in an amount of 0.1 to 10% by weight based on the substrate, and the mixture is used under hydrogen pressure at room temperature to 200 ° C. Is done. After completion of the reaction, the reaction product and the catalyst can be easily separated by filtration.
[0032]
【Example】
The present invention will be described in more detail with reference to examples.
[0033]
Example 1
30 g of nickel-aluminum (Ni: Al = 50: 50) powder was charged into 300 g of a 20% aqueous sodium hydroxide solution and treated at 90 ° C. for 1 hour. After cooling, 300 g of water was added, stirred for 10 minutes and allowed to stand for 5 minutes to settle the catalyst, and then the supernatant was removed by decantation. After this operation was performed four times, 300 g of water and 0.126 g of magnesium chloride hexahydrate were added, and after stirring for 10 minutes, the catalyst was settled and the supernatant was removed by decantation. Further, 300 g of water and 0.416 g of sodium molybdate were added and stirred at 20 ° C. for 30 minutes to obtain a molybdenum-containing developed sponge nickel catalyst. The molybdenum content of the obtained catalyst was measured by atomic absorption spectroscopy. As a result, it was 1.05% by weight. The Mo content in the wastewater (300 ml) was 22 ppm.
[0034]
Comparative Example 1
30 g of nickel-aluminum (Ni: Al = 50: 50) powder was charged into 300 g of a 20% aqueous sodium hydroxide solution and treated at 90 ° C. for 1 hour. After cooling, 300 g of water was added, and the mixture was stirred for 10 minutes and allowed to stand for 5 minutes to settle the catalyst. Then, the supernatant was removed by decantation. After performing this operation four times, 300 g of water and 0.416 g of sodium molybdate dihydrate were added, and the mixture was stirred at 20 ° C. for 30 minutes to obtain a molybdenum-containing developed sponge nickel catalyst. The molybdenum content of the obtained catalyst was measured by atomic absorption spectroscopy. As a result, it was 0.60% by weight. The Mo content in 300 ml of the drainage was 220 ppm.
[0035]
Comparative Example 2
30 g of nickel-aluminum-molybdenum (Ni: Al: Mo = 47: 50: 3) powder was charged into 300 g of a 20% aqueous sodium hydroxide solution and treated at 90 ° C. for 1 hour. After cooling, 300 g of water was added, and the mixture was stirred for 10 minutes, allowed to stand for 5 minutes to settle the catalyst, and then the supernatant liquid was removed by decantation eight times to obtain a developed molybdenum-containing sponge nickel catalyst. The molybdenum content of the obtained catalyst was measured by atomic absorption spectrometry, and was found to be 1.03% by weight. The Mo content in 300 ml of the drainage was 2,400 ppm.
[0036]
Example 2
200 g of a 50% aqueous glucose solution was charged into a 500 ml electromagnetically stirred autoclave, 2 g of the developed nickel catalyst prepared in Example 1 was charged, and after sufficient replacement with hydrogen, the reaction was started at a reaction temperature of 150 ° C. and a reaction pressure of 5 MPa, and hydrogen was absorbed. The reaction was continued until the reaction stopped completely. The time required for the reaction was 2 hours.
[0037]
Comparative Example 3
The reaction was carried out in the same manner as in Example 2 except that the catalyst prepared in Comparative Example 1 was used. As a result, the time required for the reaction was 2.6 hours.
[0038]
Comparative Example 4
The reaction was carried out in the same manner as in Example 2 except that the catalyst prepared in Comparative Example 2 was used. As a result, the time required for the reaction was 2.5 hours.
[0039]
[Table 1]

[0040]
As is clear from the results shown in Table 1, when Example 1 and Comparative Example 1 were compared, in Example 1, the molybdenum supporting efficiency for the catalyst became extremely large because of the pretreatment with magnesium chloride, and the catalyst was supported on the catalyst. As a result of the increase in the amount of molybdenum, the content of molybdenum in the wastewater is reduced.
[0041]
Further, the catalyst of Example 1 obtained by the method of the present invention was superior to the molybdenum-supported sponge metal catalyst of Comparative Examples 1 and 2 prepared from an alloy adjusted to the same amount of molybdenum, in terms of the hydrogenation reaction of glucose. Has catalytic activity.
[0042]
【The invention's effect】
According to the method of the present invention, a molybdenum-supported sponge metal catalyst useful as a sponge metal catalyst can be produced cost-effectively and with minimum damage to the environment.
[0043]
Further, the molybdenum-supported sponge catalyst produced according to the present invention is useful as a hydrogenation catalyst or a dehydrogenation catalyst.

Claims (3)

A method for producing a molybdenum-supported sponge metal catalyst by bringing an aqueous solution containing molybdic acid and / or molybdate into contact with a sponge metal catalyst, the method comprising the steps of: A method for producing a molybdenum-supported sponge metal catalyst, comprising bringing a sponge metal catalyst into contact with an aqueous solution containing molybdic acid and / or molybdate at pH 4 to 12 after contacting the metal catalyst. A hydrogenation catalyst comprising a molybdenum-supported sponge catalyst obtained by the method according to claim 1. A dehydrogenation catalyst comprising a molybdenum-supported sponge catalyst obtained by the method according to claim 1.