JPH0782202A - Method for producing ketones - Google Patents

Abstract

(57) [Summary] [Objective] Ketones are produced by a dehydrogenation reaction with a catalyst having a high reaction activity, a high selectivity to a ketone, and a thermally stable structure. [Constitution] Acetone is produced from 2-propanol by using hectorite exchanged with cesium ion as a catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing ketones such as acetone and methyl ethyl ketone.

[0002]

2. Description of the Related Art A method for producing ketones such as acetone and methyl ethyl ketone by dehydrogenating a secondary alcohol in the presence of a catalyst has been well known. For example, acetone can be obtained by dehydrogenating 2-propanol, and methyl ethyl ketone can be obtained by dehydrogenating sec-butanol.
Regarding such a dehydrogenation catalyst, JP-A-57-387
Japanese Patent Laid-Open No. 38-358135 discloses a method of producing using a Raney nickel type catalyst containing an addition metal.
Japanese Patent Publication discloses a method of producing using Raney nickel catalyst under specific reaction conditions. Since this dehydrogenation reaction is an endothermic reaction, it is generally necessary to raise the reaction temperature. However, in the presence of common solid catalysts,
In the dehydrogenation reaction of 2-propanol, a dehydration reaction is likely to occur as a side reaction as shown in the following formula, so that propylene,
Diisopropyl ether and water are produced.

Main reaction (CH ₃ ) ₂ CHOH → (CH ₃ ) ₂ CO + H ₂ Side reaction 1 (CH ₃ ) ₂ CHOH → CH ₃ CH = CH ₂ +
H ₂ O side reaction _{2 2 (CH 3) 2 CHOH} → (i-C 3 H 7) 2 O
+ H ₂ O

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dehydrogenation reaction with a catalyst having a high reaction activity and a high selectivity to a ketone and having a thermally stable structure.

[0005]

DISCLOSURE OF THE INVENTION As a result of intensive studies on the above problems, the present inventors have found that a synthetic hectorite clay having a two-dimensional layered structure and a card house structure that can be used even at high temperatures, or an ion exchange thereof. The inventors have found a method of selectively obtaining ketones in a high yield using the body and completed the present invention.

That is, the present invention is a method for producing ketones from secondary alcohols, which uses hectorite or ion-exchanged hectorite as a catalyst. The present invention will be described below.

Hectorite used in the present invention is a kind of layered clay mineral. The layered clay mineral is an ion-exchangeable layered crystal, and the unit layer forming the layered structure has an oxygen tetrahedral layer centered on Si and an oxygen octahedral layer centered on aluminum and magnesium. These are two-dimensionally combined to form a layered structure. This tetrahedral layer and octahedral layer are combined in a ratio of 1: 1 to form a 1: 1 type clay, and a tetrahedral layer centered around the octahedral layer is sandwiched between 2: 1 type clays. Is.

Hectorite is classified into smectite clay, which is one of the 2: 1 type clays, and is further classified into a trioctahedral structure because the substituted metal in the octahedral layer is mainly divalent. It has a different structure from montmorillonite, which has a dioctahedral structure in which the substitutional metal of the face layer is mainly trivalent. As such a hectorite, one represented by the following formula is generally used.

Na _1/3 [Mg _{3-1 / 3} Li _1/3 ] {Si ₄ } O ₁₀ X ₂ (wherein X represents OH or F) This hectorite may also be synthesized. It may be naturally produced. The hectorite may be a simple substance or a layered clay mineral containing the hectorite. As the layered clay mineral containing hectorite, a smectite type clay mineral can be used in particular. That is, hectorite and those containing, for example, montmorillonite, saponite, bentonite, beidellite, nontronite, sauconite, etc. other than hectorite can be used.
In this case, the hectorite content is preferably 50% or more.

In the present invention, not only hectorite is used as a catalyst, but ion-exchanged hectorite is also used as a catalyst. The ion-exchanged hectorite catalyst is prepared as follows. That is, a compound used for ion exchange is an inorganic acid salt such as lithium, sodium, potassium, rubidium or cesium metal carbonate such as carbonate, nitrate, sulfate or phosphate, or an organic acid salt such as acetic acid or oxalic acid. Examples thereof include acids or complex salts such as ammine complexes, and the compounds are not particularly limited as long as they generate ions in an aqueous solution, but cesium compounds are preferable.

The ion exchange is carried out by immersing hectorite in an aqueous solution containing the above-mentioned alkali metal compound. At this time, the aqueous solution concentration of the alkali metal compound is not particularly limited, but is set to about 0.01 to 1 mol / l and is at least equal to or more than the ion exchange capacity of the hectorite to be treated, preferably equal to or more than twice. Treatment with an aqueous solution containing an alkali metal compound is preferred.
The temperature for ion exchange is 0 to 90 ° C, preferably 10
It is suitable to set the temperature to ˜70 ° C. The ion exchange can be sufficiently performed even at room temperature. The time required for ion exchange is 1 to 50 hours, and usually about 5 to 30 hours is sufficient. The amount of ion exchange is at least 30% or more, preferably 50% of the ion exchange capacity of hectorite.
The above is preferable. Further, at the time of ion exchange, it is preferable to gently stir in order to disperse the hectorite in the aqueous solution. After performing ion exchange for a predetermined time, the ion-exchanged hectorite is filtered and washed with water. Washing with water is preferably performed until alkali metal ions are no longer detected in the washing liquid.

The hectorite ion-exchanged by the above method is then dried. Drying is performed in an air atmosphere or a nitrogen atmosphere at room temperature to 200 ° C., preferably 50 to 1
It is carried out at a temperature of 00 ° C. under normal pressure or reduced pressure.

The hectorite or the ion-exchanged hectorite thus obtained may be molded with a suitable binder and used as a catalyst, if necessary.

The synthesis of the ketone by the dehydrogenation reaction of the secondary alcohol is not particularly limited as long as the alcohol can be brought into contact with the catalyst in the gas phase, but the fixed bed flow reaction is usually preferred. The reaction temperature is usually 300 to 600 ° C., preferably 350 to 500 ° C., and the pressure is not particularly limited, and it can be carried out at normal pressure or under pressure. If necessary, it is preferable to carry out the reaction in the presence of an inert gas such as nitrogen.

[0015]

EXAMPLES The present invention will now be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1 500 g of an aqueous cesium carbonate solution prepared to 0.1 mol / l
Is a Na-type hectorite (abbreviated as Na-SW)
4 g of N) was dipped and ion-exchanged while stirring at room temperature for 24 hours.

Na _1/3 [Mg _{3-1 / 3} Li _1/3 ] {Si ₄ } O ₁₀ (OH) ₂ Then, the aqueous solution is filtered, washed with water until cesium ions are no longer detected, and then at 50 ° C. under nitrogen. It was dried under reduced pressure in an atmosphere to obtain a catalyst (abbreviation Cs-SWN).

0.35 g of the catalyst was filled in a flow reaction tube and pretreated at 450 ° C. for 2 hours under a nitrogen stream. Subsequently, the reaction temperature was set to 450 ° C., and 2-propanol was added to 1.
It was distributed at 82 ml / h. At the same time, nitrogen gas
Flowed at 00 ml / h.

Analysis of the reaction solution 3 hours after the start of the reaction revealed that the conversion of 2-propanol was 36.0%, the selectivity of acetone was 41.4%, and the yield of acetone was 14.9%.

Example 2 Na-type hectorite (Na-SWN) used in Example 1
Was used as a catalyst without ion exchange. As a result of reacting in the same manner as in Example 1, the conversion rate of 2-propanol was 2
The acetone selectivity was 1.7%, the acetone selectivity was 34.1%, and the acetone yield was 7.4%.

Example 3 Na-type hectorite represented by the following formula (abbreviation: Na-SWF)
Was subjected to cesium ion exchange in the same manner as in Example 1 to obtain a catalyst (abbreviation Cs-SWF).

Na _1/3 [Mg _{3-1 / 3} Li _1/3 ] {Si ₄ } O ₁₀ F ₂ Table 1 shows the results of the same reaction as in Example 1.

Example 4 Na-type hectorite (Na-SWF) used in Example 3
Was used as a catalyst without ion exchange. Table 1 shows the results of the reaction performed in the same manner as in Example 1.

Comparative Example 1 and Comparative Example 2 Na-type saponite (abbreviation: Na-S, Comparative Example 1) and cesium ion-exchanged saponite (abbreviation: Cs-) obtained by ion exchange of Na-S in the same manner as in Example 1. Table 1 shows the results of the reaction in the same manner as in Example 1 using S and Comparative Example 2) as a catalyst.

Comparative Examples 3 and 4 Na-type montmorillonite (abbreviation: Na-M, Comparative Example 3),
And Na-M were ion-exchanged in the same manner as in Example 1 to obtain cesium ion-exchanged montmorillonite (abbreviation Cs-
Table 1 shows the results of the same reaction as in Example 1 using M and Comparative Example 4) as a catalyst.

Comparative Example 5 To 1 liter of an aqueous potassium chloride solution prepared at 0.5 mol / l, Na-Y type zeolite (SiO ₂ / Al ₂ O ₃ =
4.8) 100 g was immersed and ion-exchanged at 70 ° C. for 3 hours, and then the supernatant was removed by a gradient method. This ion exchange operation was repeated 10 times. Then, using 1 liter of an aqueous solution of cesium chloride adjusted to 0.5 mol / l, 10
Ion exchange was performed once to obtain a cesium-exchanged Y-type zeolite (abbreviation Cs-Y). Example 1 using Cs-Y as a catalyst
Table 1 shows the results of the same reaction.

[0027]

[Table 1]

[0028]

EFFECTS OF THE INVENTION According to the present invention, ketones can be efficiently produced from secondary alcohols by using a catalyst having a high reaction activity, a high selectivity to ketones, and a thermally stable structure. You can

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Claims (3)

[Claims] 1. A method for producing ketones from secondary alcohols, which uses hectorite or ion-exchanged hectorite as a catalyst. 2. The method according to claim 1, wherein the catalyst is hectorite exchanged with cesium ions. 3. The method according to claim 1, wherein the secondary alcohol is 2-propanol.