JP2910296B2 - Method for producing lower fatty acid ester - Google Patents

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 a fatty acid ester by reacting a lower fatty acid and a lower olefin, thereby significantly improving productivity (hereinafter referred to as space-time yield).

[0002]

2. Description of the Related Art Conventionally, as a method for producing a corresponding ester by reacting a lower fatty acid with a lower olefin, a method using a strongly acidic cation exchange resin as a catalyst, or as disclosed in JP-B-53-6131, A method using a mineral acid such as sulfuric acid or phosphoric acid or a heteropoly acid such as phosphotungstic acid or phosphomolybdic acid as a catalyst, or an aromatic disulfonic acid and / or an ester thereof as disclosed in JP-A-57-183743. And the like have been published.

[0003]

However, in comparison with the present invention, the reaction using the above-mentioned conventional catalyst is a production method far from industrialization because the space-time yield is low and the catalyst life is short. . The present invention has been made in view of the above circumstances, and aims to find a catalyst having a significantly higher space-time yield than the conventional method and a long life, and to provide a method for easily producing a lower fatty acid ester. And

[0004]

In order to achieve the above-mentioned object, in the method of the present invention, (1) a cesium salt of phosphomolybdic acid or silico-molybdic acid is used as a catalyst;
The lower fatty acid and the lower olefin are reacted in the presence of at least one molybdate catalyst selected from the group consisting of rubidium acid, (3) thallium salt, (4) ammonium salt, and (5) potassium salt.

The lower fatty acids used in the method of the present invention include formic acid, acetic acid, propionic acid, valeric acid, acrylic acid, methacrylic acid and crotonic acid, and the lower olefins include ethylene, propylene, butene- 1,
Butene-2 and isobutylene are listed.

When an olefin having 5 or more carbon atoms is used, the reaction for forming a fatty acid ester is slow. If the reaction pressure or the reaction temperature is increased to compensate for the increase, not only the by-products such as polymers are increased, but also the catalyst life is increased. Also becomes significantly shorter.

The reaction mode according to the present invention can be any of a liquid phase reaction and a gas phase reaction, but a gas phase reaction is particularly preferred. In a gas phase reaction, it is necessary to make a large excess of a lower olefin relative to a lower fatty acid. Reaction pressure 0.50kg
/ Cm ² G, preferably in the range of 0 to 10 kg / cm ² G. The pressure is much lower than 10 to 150 kg / cm ² G in the case of liquid phase reaction.

[0008] The reaction temperature is preferably in the range of 50 to 300 ° C, particularly 100 to 250 ° C, in both the gas phase and the liquid phase. If the reaction temperature is lower than 50 ° C., the reaction rate becomes slow,
The space-time yield is significantly reduced. On the other hand, when the temperature exceeds 300 ° C., by-products increase and the catalyst life is shortened.

The lower fatty acid concentration of the feed is preferably 3 to 30% by volume, more preferably 5 to 20% by volume, and the molar ratio of (lower olefin / lower fatty acid) is preferably 3 to 20. Also, the presence of water in the gas phase reaction produces alcohol,
Although the reason is not clear, adding about 1% by volume of steam to the raw material gas increases the catalyst life.

[0010] In the gas phase reaction, the mixture gas in the standard state, a space velocity (SV) 100~5000hr ^-1, preferably particularly through the catalyst at 300~2000hr ^-1.

The molybdenum acid salt used in the present invention is:
The larger the surface area, the stronger the acid strength, and the larger the amount of acid, the better, and it may be used by itself or supported on a carrier.

The carrier to be used may be any porous material generally used as a carrier or a substance capable of granulating into porous material, and examples thereof include silica, silica grass, titania, and activated carbon.

The above molybdate catalyst is prepared by, for example, dissolving commercially available phosphomolybdic acid or silico-molybdic acid in water and adding cesium, rubidium, thallium, ammonium, potassium nitrate or carbonate as powder, or Add as an aqueous solution and mix. Then, most of the water is removed by evaporation in a hot water bath, and the obtained solid is subjected to a heat treatment at 50 to 350 ° C, preferably 100 to 300 ° C, under an atmosphere of an inert gas such as air or nitrogen. Can be When the temperature is lower than 50 ° C., the removal of water becomes insufficient, and when the temperature is higher than 350 ° C., the catalyst deteriorates.

The above catalyst has a high selectivity and shows 90% or more of unsaturated carboxylic acid such as acrylic acid and 95% or more of saturated carboxylic acid such as acetic acid.

[0015]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples.

Example 1 Using a 1 liter flask, 125 g of commercially available (moisture) phosphomolybdic acid was added to 60 g of pure water.
Add cc and dissolve. Separately, cesium nitrate (CsNO ₃ ) 2
An aqueous solution in which 5.7 g is dissolved is prepared and added dropwise to the above phosphomolybdic acid aqueous solution with stirring using a dropping funnel. Fine crystals precipitate at the same time as the dropping. Place the 11 flask in a water bath and evaporate most of the water in the flask at boiling. The lump thus obtained is taken out on a petri dish, placed in a dryer, and dried in air at 150 ° C. for 13 hours. The dried product is pulverized, and a product having a diameter of 1 to 2 mm is collected by using a sieve, and 10.7 cc thereof is used as a catalyst for the reaction.

While maintaining the reaction temperature at 150 ° C. and the reaction pressure at normal pressure, a mixed gas of acetic acid, ethylene and water vapor (volume ratio: 6.8: 92.2: 1) was 10.7 l / hr (converted to standard state). Flow at a flow rate of Four hours after the start of gas flow, the conversion of acetic acid was 18.8%, and the yield was 18.6% (gas chromatography analysis). The space-time yield of ethyl acetate determined from this result is 50.

Embodiment 2 FIG. Example 1 was the same as Example 1 except that 35.2 g of thallium nitrate (TlNO ₃ ) was used instead of cesium nitrate.

Embodiment 3 FIG. Example 1 was the same as Example 1 except that instead of cesium nitrate, 15.3 g of rubidium carbonate (Rb ₂ CO ₃ ) was used.

Embodiment 4 FIG. Except that 10.6 g of ammonium nitrate (NH ₄ NO ₃ ) was used instead of cesium nitrate,
The same as in Example 1.

Embodiment 5 FIG. Example 1 except that 13.3 g of potassium nitrate (KNO ₃ ) was used instead of cesium nitrate.
Same as.

Comparative Example 1 Commercially available phosphomolybdic acid 125
g is dried at 150 ° C. for 13 hours and then molded into tablets. The mixture was further pulverized, fractionated with a sieve having a diameter of 1 to 2 mm, and subjected to the reaction using 10.7 cc as a catalyst.

Embodiment 6 FIG. Example 1 was the same as Example 1 except that the same catalyst as in Example 1 (Cs salt of phosphomolybdic acid) was used, and acrylic acid was used instead of acetic acid.

Embodiment 7 FIG. Example 1 was the same as Example 1 except that the same catalyst (Cs salt of phosphomolybdic acid) was used and propylene was used instead of ethylene.

Example 8 Using a 1 l flask, 125 g of commercially available silicomolybdic acid was dissolved by adding 60 cc of pure water. Separately, the operation after preparing an aqueous solution in which 26.1 g of cesium nitrate (CsNO ₃ ) was dissolved was performed in the same manner as in Example 1 to prepare a catalyst and perform a reaction.

Comparative Example 2 Commercially available silicomolybdic acid 125
g is dried at 150 ° C. for 13 hours and then molded into tablets. Further, the mixture was pulverized, fractionated into a piece having a diameter of 1 to 2 mm using a sieve, and subjected to the reaction using 10.7 cc as a catalyst.

The results of Examples 1 to 8 and Comparative Examples 1 and 2 are collectively shown in Table 1. In Examples 1 to 8, 1
Although the operation was continued for 00 hours, the space-time yield of the target component relative to acetic acid or acrylic acid hardly decreased, and Comparative Example 1,
In Examples 2 and 3, the yield decreased by 2 to 5% in 20 hours.

[0028]

[Table 1]

Embodiment 9 FIG. Withstand pressure 300kg / cm ² , inner volume 3
100 ml of acetic acid, 10.0 g of cesium phosphomolybdate and 1.0 g of water in a 00 ml autoclave equipped with a stirrer.
g of propylene, and propylene is introduced.
The temperature was raised to 50 ° C., the pressure was maintained at 10 kg / cm ² G, and the reaction was carried out for 1 hour.

As the reaction progresses, the reaction pressure decreases, but propylene is replenished each time from a propylene cylinder placed in a heating bath, and the inlet pressure and the reaction pressure are kept at 1
It was made possible to keep the pressure at 0 kg / cm ² G. After the reaction, the mixture was cooled to room temperature, and unreacted propylene was released, and then analyzed by gas chromatography. As a result, the conversion of acetic acid was 25.0%, and the yield of
23.5%.

[0031]

As described above, in the method of the present invention, at least one type of molybdenum selected from cesium, rubidium, ammonium, thallium and potassium salts of phosphomolybdic acid or silico molybdic acid is used. Since an acid salt is used as a catalyst, the space-time yield is high and the catalyst life is long, so that there is an advantage that a lower fatty acid ester such as an acrylate ester or an acetate ester can be efficiently produced.

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI // C07B 61/00 300 C07B 61/00 300 (72) Inventor Shoichiro Wakabayashi 2nd place in Odai, Oita City, Oita Prefecture Showa Denko (56) References JP-A-48-39425 (JP, A) JP-A-54-52025 (JP, A) JP-B-47-42808 (JP, B1) (58) Fields investigated ( Int.Cl. ⁶ , DB name) C07C 69/14 C07C 67/04 C07C 69/54

Claims (1)

(57) [Claims] When producing a fatty acid ester by esterifying a lower fatty acid with a lower olefin, (1) a cesium salt of phosphomolybdic acid or silico-molybdic acid;
A lower fatty acid characterized by reacting in the presence of a catalyst of at least one molybdate selected from the group consisting of (2) rubidium salt, (3) thallium salt, (4) ammonium salt, and (5) potassium salt. Method for producing ester.