JP4150771B2 - Catalyst for cyclohexanol dehydrogenation - Google Patents

Description

【００２２】
表１の結果から、本発明の触媒により、シクロヘキサノールの脱水素反応において高いシクロヘキサノン収率を長期間にわたって得られることが示された。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to enhancement of the performance of a catalyst for producing cyclohexanone by cyclohexanol dehydrogenation reaction.
[0002]
[Prior art]
Conventionally, in the cyclohexanol dehydrogenation reaction for producing cyclohexanone, a catalyst mainly composed of copper oxide has been used, and catalysts with various components added to improve the catalyst performance are well known. For example, a catalyst obtained by adding magnesium oxide or the like to copper oxide is described in former USSR patents SU1833199, SU1482907 and SU697179, and Chinese CN1056067. However, the magnesium oxide added to these catalysts reacts with the water contained in the reactants to form hydroxides, which reduce the mechanical strength of the catalyst or collapse the catalyst. It is the cause.
[0003]
In addition, U.S. Pat.No. 4,918,293 discloses a catalyst to which copper oxide, zinc oxide and aluminum oxide are added, and European Patent EP 104046 discloses a catalyst to which zinc oxide and an alkali metal oxide are added. In any catalyst, a decrease in the dehydrogenation activity of the catalyst, which is considered to be caused by the formation and adhesion of a polymer or the like, was observed. Therefore, a catalyst that reduces or eliminates the above problems has been desired.
[0004]
[Problems to be solved by the invention]
Therefore, the problem to be solved by the present invention is to provide a high-performance catalyst that maintains high activity for a long time in the cyclohexanol dehydration reaction.
[0005]
[Means for Solving the Problems]
As a result of diligent research in view of the above-described prior art, the present inventor has found that a catalyst comprising copper oxide, zinc oxide and magnesium aluminate exhibits high activity for a long time in a cyclohexanol dehydrogenation reaction. The present invention has been completed.
[0006]
That is, the present invention provides a cyclohexanol dehydrogenation catalyst comprising copper oxide, zinc oxide, magnesium aluminate and aluminum oxide. In the catalyst of the present invention, since the magnesium component in the catalyst forms a compound with aluminum, it does not generate hydroxide by reacting with water contained in the reaction product, and is stable during the reaction process. High mechanical stability and excellent performance stability.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The cyclohexanol dehydrogenation catalyst of the present invention is a catalyst comprising copper oxide, zinc oxide and magnesium aluminate. When the total weight of the catalyst is 100% by weight, the content of each component is 20 to 60 copper oxide. % By weight, zinc oxide 30-70% by weight and magnesium aluminate 0.1-10% by weight, preferably 0.3-7% by weight. For catalysts outside this range, the degree of cyclohexanol dehydrogenation activity or the stability over time of the activity is insufficient. The magnesium aluminate in the catalyst is considered to have an action of suppressing the production of a polymer on the catalyst. In addition, the catalyst of this invention can contain the other components (for example, aluminum oxide, silicon oxide, etc.) which do not reduce catalyst performance further.
The invention will be further described with reference to the following examples.
[0008]
An example of the method for producing the catalyst of the present invention is shown below. The catalyst of the present invention generates a precipitate which is a precursor of the catalyst of the above-mentioned components by a known coprecipitation method, a sequential precipitation method, etc., and then the precipitate is washed and dried, and then heated at 350 to 650 ° C. It can manufacture by baking at temperature. In the catalyst firing step, it is important to form the magnesium aluminate by appropriately adjusting the particle size and reactivity of the precursor. As other catalyst production methods, it is possible to produce them by a known appropriate combination such as a combination of a coprecipitation method and an impregnation method. It is important that the composition of copper oxide, zinc oxide and magnesium aluminate in the catalyst is within the above range.
[0009]
Water-soluble salts such as nitrates and sulfates can be used as raw materials for the copper, zinc, magnesium and aluminum components of the catalyst of the present invention.
[0010]
The catalyst of the present invention is not particularly limited in its shape or particle diameter, and can be appropriately selected according to the reaction method (gas phase or liquid phase), the shape of the reactor, etc. good.
[0011]
The catalyst after calcination needs to reduce the copper oxide in the catalyst to metallic copper in advance before use in the reaction.
[0012]
【The invention's effect】
With the catalyst of the present invention, high dehydrogenation efficiency can be obtained over a long period of time in the cyclohexanol dehydrogenation reaction.
[0013]
The following examples illustrate the invention in detail.
[0014]
【Example】
[Example 1] (so that magnesium aluminate is 0.1% by weight)
A solution prepared by dissolving 31.9 g of copper nitrate trihydrate, 41.3 g of zinc nitrate hexahydrate, 7.7 g of aluminum nitrate nonahydrate and 2.2 g of magnesium nitrate hexahydrate in distilled water to make 300 ml A and a solution B obtained by dissolving 36.7 g of anhydrous sodium carbonate in distilled water to 300 ml were dropped into 400 g of distilled water at a rate of 7 ml / min to obtain a precipitate. The resulting precipitate was aged for 3 days, filtered and washed, and then dried at 110 ° C. overnight. The precipitate after drying was calcined in the air at 400 ° C. for 3 hours to obtain a catalyst.
[0015]
0.3 ml of the obtained catalyst was filled into a reaction tube, and a mixed gas of helium and hydrogen (90% by volume of helium, 10% by volume of hydrogen) was supplied at a flow rate of 300 ml / min. Reduction was performed. After reducing the catalyst, helium and cyclohexanol (containing 2% by weight of water) were supplied to the reaction tube, the temperature was 240 ° C., the pressure was 4 kg / cm ² G, the molar ratio of helium to cyclohexanol was 4, and the cyclohexanol The reaction was carried out under reaction conditions of a supply rate of 4.5 ml / h.
[0016]
The reaction product was analyzed by gas chromatography to check the yield of cyclohexanone. The results are shown in Table 1.
[0017]
[Example 2]
In solution A, 29.5 g of copper nitrate trihydrate, 35.4 g of zinc nitrate hexahydrate, 7.1 g of aluminum nitrate nonahydrate and 10.2 g of magnesium nitrate hexahydrate were used. A catalyst was obtained in the same manner as in Example 1 using 36.1 g of sodium carbonate. Using 0.3 ml of the obtained catalyst, a dehydrogenation reaction of cyclohexanol was carried out according to Example 1, and then the reaction product was analyzed by gas chromatography to check the yield of cyclohexanone. The results are shown in Table 1.
[0018]
[Example 3]
In solution A, 27.0 g of copper nitrate trihydrate, 29.2 g of zinc nitrate hexahydrate, 6.5 g of aluminum nitrate nonahydrate and 18.7 g of magnesium nitrate hexahydrate were used. A catalyst was obtained in the same manner as in Example 1 using 40.2 g of sodium carbonate. Using 0.33 ml of the obtained catalyst, cyclohexanol was dehydrogenated according to Example 1, and then the reaction product was analyzed by gas chromatography to examine the yield of cyclohexanone. The results are shown in Table 1.
[0019]
[Example 4] (so that magnesium aluminate has an upper limit of 10 or 7% by weight)
In solution A, 21.5 g of copper nitrate trihydrate, 15.5 g of zinc nitrate hexahydrate, 6.4 g of aluminum nitrate nonahydrate and 37.2 g of magnesium nitrate hexahydrate were used. Using 44.8 g of sodium carbonate, a catalyst was obtained in the same manner as in Example 1. Using 0.4 ml of the obtained catalyst, a dehydrogenation reaction of cyclohexanol was carried out according to Example 1, and then the reaction product was analyzed by gas chromatography to check the yield of cyclohexanone. The results are shown in Table 1.
[0020]
[Comparative Example 1]
Implementation using 32.5 g of copper nitrate trihydrate, 43.0 g of zinc nitrate hexahydrate and 7.9 g of aluminum nitrate nonahydrate for solution A and 40.2 g of anhydrous sodium carbonate for solution B A catalyst was obtained in the same manner as in Example 1. Using 0.3 ml of the obtained catalyst, a dehydrogenation reaction of cyclohexanol was carried out according to Example 1, and then the reaction product was analyzed by gas chromatography to check the yield of cyclohexanone. The results are shown in Table 1.
[0021]
[Table 1]

[0022]
From the results of Table 1, it was shown that a high cyclohexanone yield can be obtained over a long period of time in the dehydrogenation reaction of cyclohexanol by the catalyst of the present invention.

Claims (1)

A catalyst for cyclohexanol dehydrogenation reaction comprising copper oxide, zinc oxide, magnesium aluminate and aluminum oxide.