JPH0892164A - Production of pivaloylacetic acid ester - Google Patents

Abstract

PURPOSE: To readily obtain the ester useful as a synthetic intermediate for photographic materials, etc., in a high yield by carrying out decarbonylation reaction of pivaloylpyruvic acid ester using a stable specific catalyst having high activity. CONSTITUTION: (C) This method for producing a pivaloylpyruvic acid ester of formula II (e.g. methyl pivaloylpyruvate) is to subject (B) a pivaloylpuruvic acid ester of formula I (R is a 1-4C alkyl) (e.g. methyl pivaloylpyruvate) to decarbonylation reaction in the presence of (A) an inorganic oxide containing >=10wt.%, preferably >=30%, further preferably >=90% alumina expressed in terms of aluminum oxide (Al2 O3 ) and not containing a heavy metal. Furthermore, the component A is preferably added to the component B in an amount of 0.1-10%, preferably 0.5-5% based on the component B. The component A has preferably 0.5-3mm particle diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing pivaloyl acetate, and more particularly to a method for producing a pivaloyl acetate with a high yield by decarbonylating pivaloyl pyruvate. Pivaloyl acetate is a very useful compound as a synthetic intermediate for photographic materials and the like.

[0002]

2. Description of the Related Art As a method for producing a pivaloyl acetate by decarbonylating a pivaloyl pyruvate, a metal selected from the group consisting of iron, copper, nickel, manganese, chromium, molybdenum and cobalt is used as a catalyst. (See Japanese Patent Publication No. 62-47170) and a decarbonylation reaction in the presence of powdered glass (US252).
7306) is known.

[0003]

However, none of these methods can be said to have high activity of the catalyst, and further, there are problems which are industrially unsatisfactory. That is,
In the former method, since the heavy metal as described above is used as a catalyst, not only the recovery and post-treatment thereof become more complicated, but also carbon monoxide as a by-product reacts with these heavy metals to produce toxic metal carbonyls. There is also the risk of creating.
Further, there is a big problem that the recovery rate of iron powder is low when the most active iron powder is used. On the other hand, in the latter method, the reaction is carried out in a liquid phase using a large amount of the catalyst of 10 to 11% by weight of the raw material in order to obtain the pivaloyl acetate in a good yield. There is a problem that it becomes complicated.

The present invention provides a method for producing a pivaloyl acetic acid ester by decarbonylating a pivaloyl pyruvic acid ester to produce a high yield of pivaloyl acetic acid ester using a highly active and stable catalyst. It is an object of the present invention to provide a method for producing pivaloyl acetic acid ester, which is capable of producing a pivaloyl acetate and in which the catalyst can be easily recovered and post-treated.

[0005]

The object of the present invention is to convert aluminum into aluminum oxide (Al ₂ O ₃ ).
This is achieved by a method for producing a pivaloyl acetic acid ester, which comprises subjecting a pivaloyl pyruvic acid ester to a decarbonylation reaction in the presence of an inorganic oxide containing 0% by weight or more and not containing a heavy metal.

The present invention will be described in detail below. Pivaloyl pyruvate is a compound represented by the general formula (I).

[Chemical 1] (In the formula, R represents an alkyl group having 1 to 4 carbon atoms)

Specific examples thereof include methyl pivaloylpyruvate, ethyl pivaloylpyruvate and n-propyl pivaloylpyruvate.

The pivaloyl acetic acid ester produced by decarbonylation of pivaloyl pyruvic acid ester is a compound represented by the general formula (II), specifically, methyl pivaloyl acetate, ethyl pivaloyl acetate, n-propyl pivaloyl acetate. Etc.

[Chemical 2] (In the formula, R represents an alkyl group having 1 to 4 carbon atoms)

In the present invention, aluminum is contained in an amount of 10% by weight or more, preferably 30% by weight or more, more preferably 90% by weight or more in terms of aluminum oxide (Al ₂ O ₃ ), and iron, copper, nickel, The decarbonylation reaction of pivaloylpyruvate ester is carried out in the presence of an inorganic oxide containing no heavy metals such as manganese, chromium, molybdenum and cobalt as a catalyst. When the aluminum content in the inorganic oxide is low, the reaction time becomes long when the reaction is carried out in the liquid phase, and the catalyst amount must be increased in order to increase the conversion rate when the reaction is carried out in the gas phase. Thermal decomposition of pivaloyl pyruvic acid ester is also likely to occur and the yield of the target pivaloyl acetic acid ester will be reduced.

Examples of the inorganic oxides include α-alumina, γ-alumina, η-alumina, β-alumina and δ.
-Alumina such as alumina, zeolite A, zeolite B
And the like, synthetic sieves such as molecular sieve 3A, molecular sieve 4A, molecular sieve 5A, and molecular sieve 13X, and silica-alumina. Of these, in zeolites and synthetic zeolites that have ion-exchange capacity, iron is used as the ion-exchange point,
Ions other than heavy metals such as copper, nickel, manganese, chromium, molybdenum, and cobalt, for example, alkali metal ions, alkaline earth metal ions, hydrogen ions, and ammonium ions may be ion-exchanged and carried.
The inorganic oxide preferably has a small particle size from the viewpoint of catalytic activity, and preferably has a large particle size from the viewpoint of handling.
Those having a particle diameter of mφ, preferably 0.5 to 3 mmφ are suitably used.

In the present invention, the decarbonylation reaction of pivaloylpyruvate can be carried out in the liquid phase or the gas phase. In the case of the liquid phase method, the reaction is usually carried out by adding the pivaloyl pyruvate ester and the inorganic oxide to a reactor and
It is carried out by heating the liquid phase at 0 to 280 ° C, preferably 150 to 200 ° C. At this time, the reaction pressure is not particularly limited, but is usually atmospheric pressure. The inorganic oxide is usually 0.1 to 10% by weight, preferably 0.1% by weight, based on the pivaloylpyruvate ester as a raw material.
5 to 5% by weight is added. The reaction is usually completed in 0.5 to 5 hours. After the reaction, the reaction product is separated and purified by distilling the reaction solution as it is, and the catalyst is easily recovered by filtration or the like.

[0012] In the case of the gas phase method, the reaction is usually carried out in a reaction tube filled with the above-mentioned inorganic oxide in a vaporizer or a vaporization layer, and an inert gas such as pivaloyl pyruvate ester and nitrogen gas. It is carried out by continuously supplying a mixed gas of and as a raw material gas. At this time, the reaction pressure is not particularly limited, but is usually atmospheric pressure. Also,
The reaction temperature is usually 150 to 300 ° C, preferably 180 to
250 ° C., the space velocity of the raw material gas containing pivaloyl pyruvate is usually 50 to 3000 hr ⁻¹ ,
Preferably at 100～1500Hr ^-1, the concentration of pivaloyl pyruvic acid ester in the feed gas is typically 1~300g against inert gas 1 liter, preferably from 2 to 100
g. In the gas phase method, the reaction product is easily separated and purified by cooling the gas passing through the reaction tube and distilling a condensate obtained.

The catalyst whose activity has been lowered by the gas phase method can be easily recovered by taking it out of the reaction tube. However, in the present invention, the catalyst packed in the reaction tube is used as it is in acetone.
It can also be easily regenerated by washing with an organic solvent such as a lower alkyl ketone such as methyl ethyl ketone and methyl isobutyl ketone, a lower alcohol such as methanol, ethanol and propanol. The washing is usually carried out by passing the organic solvent together with an inert gas such as nitrogen gas at 20 to 40 ° C. through the catalyst layer of the reaction tube. Therefore, in the present invention, it is possible to carry out the reaction continuously for a long time without replacing the catalyst.

[0014]

EXAMPLES Next, the present invention will be specifically described with reference to examples. All the reactions were carried out under normal pressure, and the conversion of pivaloylpyruvate and the yield of pivaloylacetate were calculated in mol. The aluminum content of the catalyst is the aluminum content converted to aluminum oxide (Al ₂ O ₃ ).

Example 1 In a 50 ml glass reactor, 20 g of methyl pivaloylpyruvate having a purity of 98.9% by weight and a particle size of 1 m as a catalyst were used.
170-175 by adding 0.8 g of m-γ-alumina [Neobead RP-4A (aluminum content converted to aluminum oxide: 94.5% by weight), manufactured by Mizusawa Chemical Co., Ltd.]
The liquid phase was stirred at 0 ° C for 4 hours. Carbon monoxide was gradually generated as the reaction proceeded. After completion of the reaction, the reaction solution was analyzed by gas chromatography to find that 15.4 g of methyl pivaloyl acetate was produced (conversion rate 91.8%, yield 91.8%). Also, the catalyst, after filtering the reaction solution,
0.8g by washing with methanol and drying under reduced pressure
Were recovered (recovery rate 100%).

Example 2 In a 50 ml glass reactor, 20 g of methyl pivaloylpyruvate having a purity of 98.0% by weight and a particle size of 1 m as a catalyst were used.
0.8 g of [gamma] -alumina [KHA-24 (aluminum content converted to aluminum oxide: 99.7% by weight), manufactured by Sumitomo Chemical Co., Ltd.] of m was added and the liquid phase was adjusted to 2 at 170 to 175 ° C.
Stir for hours. Carbon monoxide was gradually generated as the reaction proceeded. After completion of the reaction, the reaction solution was analyzed by gas chromatography to find that methyl pivaloyl acetate was 14.
3g was produced (conversion rate 97.2%, yield 86.0)
%).

Example 3 In Example 1, the catalyst was 70-230 mesh α-
180 g of alumina (aluminum content converted to aluminum oxide: 99% by weight, manufactured by Kanto Kagaku)
The reaction was performed as in Example 1 except that the liquid phase was stirred at 185 ° C for 5 hours. As a result of the analysis, 14.3 g of methyl pivaloyl acetate was produced (conversion rate 95.6%, yield rate 85.4%).

Example 4 In Example 1, the catalyst was changed to molecular sieve 3A 1
/ 8 (aluminum content converted to aluminum oxide:
30% by weight, manufactured by Wako Pure Chemical Industries, Ltd.) changed to 0.8 g, 150-1
The reaction was performed in the same manner as in Example 1 except that the liquid phase was stirred at 60 ° C for 2 hours. As a result of the analysis, 14.7 g of methyl pivaloyl acetate was produced (conversion rate 97.6%, yield 8
7.7%).

Comparative Example 1 The reaction was performed in the same manner as in Example 1 except that the liquid phase was stirred for 7 hours at 175 to 180 ° C. without using a catalyst. As a result of the analysis, 6.8 g of methyl pivaloyl acetate was obtained.
It was generated (conversion rate 54.3%, yield 40.2%).

Comparative Example 2 In Example 1, the catalyst was changed to 0.8 g of 60-100 mesh silica gel (manufactured by Ishizu Seiyaku), and the liquid phase was set to 190-90.
The reaction was performed in the same manner as in Example 1 except that the mixture was stirred at 200 ° C for 7 hours. As a result of analysis, methyl pivaloyl acetate was 1
0.3 g was produced (conversion rate 77.4%, yield 61.
3%).

Comparative Example 3 In Example 1, the catalyst was 1 mmφ × 10 mm zeolite [HSD-640NAD (aluminum content converted to aluminum oxide: 7.7% by weight), manufactured by Tosoh Corporation].
The reaction was performed in the same manner as in Example 1 except that the amount was changed to 0.8 g and the liquid phase was stirred at 160 to 170 ° C. for 7 hours. As a result of the analysis, 11.5 g of methyl pivaloyl acetate was produced (conversion rate 97.5%, yield 68.1%).

Comparative Example 4 A 50 ml glass reactor was charged with 30 g of methyl pivaloylpyruvate having a purity of 96.7% by weight and 1.2 g of 100 mesh electrolytic iron powder (manufactured by Wako Pure Chemical Industries) as a catalyst. The liquid phase was stirred at 200 ° C. for 3 hours. Carbon monoxide was gradually generated as the reaction proceeded. After completion of the reaction, the reaction solution was analyzed by gas chromatography to find that 21.0 g of methyl pivaloyl acetate was produced (conversion rate 100%,
Yield 85.4%). When the catalyst was recovered in the same manner as in Example 1, only 0.85 g was recovered (recovery rate 71%). The results of Examples 1 to 4 and Comparative Examples 1 to 4 are summarized in Table 1.

[0023]

[Table 1]

Example 5 A reaction tube made of stainless steel having an inner diameter of 29 mm and a length of 500 mm was used as a catalyst to form γ-alumina having a particle diameter of 1 mm [NEOBEAD RP].
-4A (aluminum content converted to aluminum oxide: 94.5% by weight, manufactured by Mizusawa Chemical Co., Ltd.) 60 ml, and heated to 230 ° C. while flowing nitrogen gas at a flow rate of 350 ml / min. Next, methyl pivaloylpyruvate having a purity of 99.5% by weight was vaporized and entrained in nitrogen gas, and added to the reaction tube at a flow rate of 2 g / min to carry out the reaction. 1 hour after starting the reaction, 30
When the condensate obtained by cooling the gas passing through the catalyst layer in 4 minutes was analyzed, it was found that methyl pivaloylacetate was 42.6 g.
It was produced (conversion rate 99.0%, yield rate 83.5%, space-time yield 1420 g / l · hr). The space-time yield (STY) (g / l · hr) of methyl pivaloylacetate was calculated by setting the reaction time to θ (hr), the amount of methyl pivaloylacetate formed during that period to a (g), and the amount of catalyst packed in the reaction tube. Was calculated by the following formula.

[0025]

[Equation 1]

Example 6 In Example 5, the catalyst was γ-alumina having a particle diameter of 1 mm [Neobead RP-4A (aluminum content converted to aluminum oxide: 94.5% by weight), manufactured by Mizusawa Chemical Co., Ltd.] 3.
The reaction was performed in the same manner as in Example 5, except that the flow rate of nitrogen gas was changed to 0 ml and the flow rate of nitrogen gas was changed to 100 ml / min. The product obtained by cooling the gas that passed through the catalyst layer from 1 hour to 30 minutes after starting the reaction was analyzed and found to have produced 41.3 g of methyl pivaloyl acetate (conversion rate 93.
2%, yield 81.4%, space-time yield 2753 g / l · h
r).

Example 7 In Example 5, the catalyst was γ-alumina having a particle size of 3 mm [Neobead DB-48 (aluminum content converted to aluminum oxide: 95.3% by weight), manufactured by Mizusawa Chemical Co., Ltd.] 6.
The reaction was performed in the same manner as in Example 5 except that the flow rate of nitrogen gas was changed to 0 ml and the flow rate of nitrogen gas was changed to 25 ml / min. The product obtained by cooling the gas that passed through the catalyst layer 1 hour to 30 minutes after starting the reaction was analyzed, and as a result, 45.2 g of methyl pivaloyl acetate was produced (conversion rate 95.5).
%, Yield 88.8%, space-time yield 1507 g / l · h
r).

Example 8 In Example 5, the catalyst was γ-alumina having a particle size of 3 mm [Neobead GB-45 (aluminum content converted to aluminum oxide: 100% by weight), manufactured by Mizusawa Chemical Co., Ltd.] 30
ml, and the flow rate of nitrogen gas to 100 ml / min,
Then, the flow rate of methyl pivaloylpyruvate was set to 1 g / mi.
The reaction was carried out in the same manner as in Example 5 except that n was changed. The product obtained by cooling the gas that passed through the catalyst layer from 1 hour to 30 minutes after starting the reaction was analyzed and found to have produced 22.0 g of methyl pivaloyl acetate (conversion rate 9
0.8%, yield 86.2%, space-time yield 1467g / l
hr).

Example 9 In Example 5, the catalyst was γ-alumina having a particle size of 1 mm [Neobead RP-4B (aluminum content converted to aluminum oxide: 94.5% by weight): manufactured by Mizusawa Chemical Co., Ltd.] 6.
Change to 0 ml and change the flow rate of nitrogen gas to 100 ml / min
And a flow rate of methyl pivaloyl pyruvate of 4 g /
The reaction was performed in the same manner as in Example 5 except that the amount was changed to min. The product obtained by cooling the gas that passed through the catalyst layer 1 hour to 15 minutes after starting the reaction was analyzed and found to have produced 47.9 g of methyl pivaloyl acetate (conversion rate 96.5%). , Yield 94.0%, space-time yield 319
3 g / l · hr).

Comparative Example 5 The reaction was performed in the same manner as in Example 5 except that the catalyst was not charged in Example 5. The product obtained by cooling the gas that passed through the catalyst layer from 1 hour to 30 minutes after starting the reaction was analyzed, and it was found that methyl pivaloyl acetate was 0.0
36g was produced (conversion rate 0.14%, yield 0.14
%).

Comparative Example 6 The reaction was carried out in the same manner as in Example 5 except that the catalyst in Example 5 was changed to 30 ml of glass beads having a particle diameter of 2 mm (aluminum content converted to aluminum oxide: 2% by weight). The product obtained by cooling the gas that passed through the catalyst layer from 1 hour to 30 minutes after starting the reaction was analyzed and found to have produced 0.18 g of methyl pivaloyl acetate (conversion rate 0.36% , Yield 0.36%, space-time yield 12g
/ L · hr).

Comparative Example 7 The catalyst used in Example 5 was changed to 30 ml of silica gel having a particle size of 1 mm [Silbead N (aluminum content converted to aluminum oxide: 2% by weight), manufactured by Mizusawa Chemical Co.], and the flow rate of nitrogen gas was 100 ml / min. The reaction was performed in the same manner as in Example 5 except that The product obtained by cooling the gas that passed through the catalyst layer between 1 hour and 1 hour after starting the reaction was analyzed, and it was found that methyl pivaloyl acetate was 1%.
1.0 g was produced (conversion rate 15.5%, yield 10.
8%, space-time yield 367 g / l · hr).

Comparative Example 8 The catalyst used in Example 5 was 1 mmφ × 10 mm zeolite [HSD-640NAD (aluminum content converted to aluminum oxide: 7.7% by weight), manufactured by Tosoh Corporation] 30
The reaction was carried out in the same manner as in Example 5, except that the flow rate of nitrogen gas was changed to 100 ml / min. The product obtained by cooling the gas that passed through the catalyst layer between 1 hour and 1 hour after starting the reaction was analyzed and found to have produced 10.6 g of methyl pivaloyl acetate (conversion rate 17.
2%, yield 10.4%, space-time yield 353g / l ・ h
r).

Comparative Example 9 In Example 5, the catalyst was 1.25 × 2.5 × 2.5 m.
The reaction was performed in the same manner as in Example 5, except that the amount of the stainless steel filler of m (Helipack: Mutual Rikagaku Glass Mfg. Co., Ltd.) was changed to 30 ml and the flow rate of methyl pivaloylpyruvate was changed to 1 g / min. The product obtained by cooling the gas which passed through the catalyst layer 1 hour to 30 minutes after starting the reaction was analyzed, and as a result, 0.33 g of methyl pivaloyl acetate was produced (conversion rate 1.9%). , Yield 1.3%, space-time yield 22g / l · hr). The results of Examples 5-9 and Comparative Examples 5-9 are summarized in Table 2.

[0035]

[Table 2]

Example 10 In Example 9, the catalyst was γ-alumina having a particle size of 1 mm [Neobead RP-4B (aluminum content converted to aluminum oxide: 94.5% by weight), manufactured by Mizusawa Chemical Co., Ltd.] 9.
Change to 0 ml and change the flow rate of methyl pivaloylpyruvate to 2
The reaction was performed in the same manner as in Example 9 except that the rate was changed to g / min. The product obtained by cooling the gas that passed through the catalyst layer from 2 hours to 30 minutes after starting the reaction was analyzed and found to have produced 44.1 g of methyl pivaloyl acetate (conversion rate 99.2%). , Yield 86.8%, space-time yield 980
g / l · hr). In addition, after 10 hours from the start of the reaction, 48.8 g of methyl pivaloyl acetate was produced (conversion rate 98.7%, yield rate 95.8%, space-time yield 1084 g / l · hr). After 20 hours and 30 minutes, 45.5 g of methyl pivaloyl acetate was formed (conversion rate 93.1%, yield rate 89.3%, space-time yield 101
1 g / l · hr). Further, after 28 hours and 30 minutes from the start of the reaction, 44.9 g of methyl pivaloyl acetate was produced (conversion rate 91.4%, yield rate 88.1%, space-time yield 998 g / l · hr). .

Example 11 In Example 9, the catalyst was γ-alumina having a particle diameter of 1 mm [Neobead RP-4B (aluminum content converted to aluminum oxide: 94.5% by weight), manufactured by Mizusawa Chemical Co., Ltd.] 5.
Change to 0 ml and change the flow rate of methyl pivaloylpyruvate to 2
The reaction was performed in the same manner as in Example 9 except that the rate was changed to g / min. The product obtained by cooling the gas that passed through the catalyst layer from 2 hours to 30 minutes after starting the reaction was analyzed and found to have produced 48.1 g of methyl pivaloyl acetate (conversion rate 97.1%). , Yield 94.4%, space-time yield 192
4 g / l · hr). Further, after 10 hours from the start of the reaction, 48.1 g of methyl pivaloyl acetate was produced (conversion rate 95.2%, yield 94.4%, space-time yield 1924 g / l · hr). , 20 hours and 30 minutes after the reaction was started, methyl pivaloyl acetate was 38.6.
g was produced (conversion rate 79.4%, yield rate 75.8%,
Space time yield 1545 g / l · hr).

Since the activity of the catalyst decreased, after 24 hours, 30 g of nitrogen gas and 100 ml / min of nitrogen gas and 3 g / min of acetone were flowed for 4 hours. After that, when the reaction was restarted by heating to 230 ° C. (restart of the first reaction), 49.4 g of methyl pivaloyl acetate was produced in 30 minutes from 4 hours after restarting the reaction (conversion rate 97.0). %, Yield 96.9%, space-time yield 1976 g / l · hr). Furthermore, after 12 hours from the restart of the reaction, 49.5 g of methyl pivaloyl acetate was produced (conversion rate 9
7.3%, yield 97.1%, space-time yield 1980g / l.
hr), 167.5 hours after restarting the reaction, 47.5 g of methyl pivaloyl acetate was produced (conversion rate 93.5%, yield 93.2%, space-time yield 1900 g / l).
-Hr).

Since the activity of the catalyst decreased a little, the reaction was restarted for the first time, and 18 hours later, acetone was flowed for 2 hours in the same manner as above. Then, when the reaction was restarted in the same manner (restart of the second reaction), 49.2 g of methyl pivaloylacetate was obtained within 4 hours and 30 minutes after restarting the reaction for the second time.
(Conversion rate 96.6%, yield rate 96.4%, space-time yield 1968 g / l · hr), the reaction was restarted for the second time, and 6 hours after 30 hours, methyl pivaloyl acetate was 4%.
8.7 g was produced (conversion rate 95.8%, yield 95.
6%, space time yield 1948 g / l · hr).

[0040]

INDUSTRIAL APPLICABILITY According to the present invention, in a method for producing a pivaloyl acetic acid ester by decarbonylating a pivaloyl pyruvic acid ester, a highly active and stable catalyst is used, and a high yield of pivaloyl acetic acid ester is easily achieved. Can be manufactured. Further, since no heavy metal catalyst is used, the problems of complicated catalyst recovery and post-treatment and formation of dangerous metal carbonyls do not occur, and the reaction can be performed in the gas phase without exchanging the catalyst. Therefore, the continuous process can be facilitated, and an industrially suitable method for producing pivaloyl acetate can be provided.

Claims (3)

[Claims] 1. A pivaloyl compound, characterized in that a pivaloyl pyruvate ester is subjected to a decarbonylation reaction in the presence of an inorganic oxide containing aluminum in an amount of 10% by weight or more calculated as aluminum oxide and containing no heavy metal. Method for producing acetic acid ester. 2. The inorganic oxide is alumina containing 90% by weight or more of aluminum in terms of aluminum oxide and containing no heavy metal.
A method for producing the pivaloyl acetate described. 3. The method for producing pivaloyl acetic acid ester according to claim 2, wherein the decarbonylation reaction is carried out in a gas phase.