JP4024388B2 - Method for producing aliphatic nitrile - Google Patents

Description

【００２１】
実施例８
実施例１で調製した触媒を使用して、ステアリン酸メチルの代わりにラウリン酸メチルを用いた以外は実施例１と同様に反応した。反応生成物を実施例１と同様に分析した結果、ラウリロニトリルの生成量は87.3（GC％）であり、また反応生成物中にはホウ素及びニオブは検出されなかった。
【００２２】
実施例９
実施例１と同様の操作を繰り返して調製した焼成前のホウ酸で処理した酸化ニオブ粉末を押し出し成形した後、 300℃で３時間焼成して成形触媒を得た。その触媒1.0gを内径10mm、長さ 500mmのステンレス製筒状反応管の中央部に充填した。アンモニアガスを88.3Ｌ/hr 、ステアリン酸メチルを1.5g/hr の速度で反応管の上部から供給し、 260℃、常圧下で反応させた。得られた反応生成物は気液分離処理し、次いで実施例１と同様にガスクロマトグラフィーでステアロニトリル生成量を測定した結果、99.2(GC ％）であった。また反応生成物中のホウ素及びニオブは検出限界以下であった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing high-quality and high-quality aliphatic nitriles.
[0002]
[Prior art and problems to be solved by the invention]
Aliphatic nitriles are generally made industrially by reaction of aliphatic carboxylic acids or their derivatives with ammonia. The reaction forms are roughly classified into a gas phase method and a liquid phase method. In the vapor phase reaction, Zr, Ta, Ga, In, Sc, Nb, Hf, Fe, Zn or Sn oxide (Japanese Patent Laid-Open No. 4-208260), aluminum oxide, silica gel, thorium oxide, etc. A method of contacting a previously vaporized aliphatic carboxylic acid or a derivative thereof with ammonia at a temperature of 250 to 600 ° C. using a catalyst has been practiced. However, the vapor phase method has a disadvantage that it costs relatively much energy compared to the liquid phase method because the raw material is vaporized.
[0003]
On the other hand, when the reaction is carried out by a liquid phase method, the aliphatic carboxylic acid or a derivative thereof is heated and dissolved in the presence of a catalyst, and ammonia gas is blown into the solution, so that the reaction is widely performed batchwise or continuously. As the catalyst used in this reaction, cobalt aliphatic carboxylate (US Pat. No. 2,493,637), iron or iron compound (Japanese Patent Laid-Open No. 58-39653), zinc oxide and the like are known. Such a catalyst exhibits high catalytic activity at a reaction temperature of 300 ° C. or lower, but all of them can be dissolved in the reaction solution, requiring special separation and recovery operations from the reaction product. This is not preferable because it causes a decrease in distillation yield and an increase in waste.
[0004]
The object of the present invention is to use a solid catalyst having a high activity at a reaction temperature of 300 ° C. or less and a reaction catalyst that is hardly soluble in the reaction of an aliphatic carboxylic acid lower alkyl ester with ammonia, It is an object of the present invention to provide a method for producing an aliphatic nitrile having a high quality and a low yield without dissolving.
[0005]
[Means for Solving the Problems]
The present inventors have found that niobium oxide treated with an acid is a solid having high activity as a catalyst and hardly soluble in the reaction solution, and the present invention has been completed.
That is, the present invention is a method for producing an aliphatic nitrile in which an aliphatic carboxylic acid lower alkyl ester and ammonia are reacted in the presence of an acid-treated niobium oxide.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The aliphatic carboxylic acid lower alkyl ester used in the present invention is a linear or branched C6-C22 saturated or unsaturated aliphatic monocarboxylic acid lower alkyl ester or dicarboxylic acid di-lower alkyl ester. Here, the lower alkyl is alkyl having 1 to 5 carbon atoms, and specific examples thereof include methyl, ethyl, propyl and isopropyl, and methyl is particularly preferable. These aliphatic carboxylic acid lower alkyl esters can be used alone or in admixture of two or more.
[0007]
Specific examples of these aliphatic carboxylic acid lower alkyl esters include methyl caproate, methyl caprylate, methyl caprate, methyl laurate, methyl myristate, methyl palmitate, methyl stearate, methyl aralate, and methyl behenate. , Methyl dimethyloctanoate, methyl butyl heptylnonanoate, methyl hexenoate, methyl octenoate, methyl decenoate, methyl dodecenoate, methyl tetradecenoate, methyl hexadecenoate, methyl octadecenoate, methyl eicosenoate, methyl docosenoate, adipic acid Examples thereof include dimethyl, dimethyl azelate, dimethyl sebacate, dimethyl decamethylene dicarboxylate, dimethyl hexadecamethylene dicarboxylate, and dimethyl octadecamethylene dicarboxylate.
[0008]
The niobium oxide treated with an acid used in the present invention refers to an acid aqueous solution and niobium oxide contacted. As the acid to be contacted, inorganic acids such as hydrochloric acid, boric acid, nitric acid, sulfuric acid and phosphoric acid are preferable, and hydrochloric acid and boric acid are particularly preferable in terms of activity and selectivity. The concentration of the acid aqueous solution is not particularly limited, but a range of 0.1 to 5 mol / L is preferable from the viewpoint of catalyst activation effect, and 0.5 to 5 mol / L is particularly preferable. At this time, the ratio of the acid to niobium oxide is preferably 0.1 to 50 mol, more preferably 0.5 to 30 mol, per mol of niobium oxide.
[0009]
In the niobium oxide treated with the acid used in the present invention, the acid may or may not remain. When the acid remains, its amount is preferably 0.05 mol or less, more preferably 0.03 mol or less, with respect to 1 mol of niobium oxide. If the remaining acid is in the above range, the acid hardly elutes in the reaction solution, and the reaction time is delayed when the resulting aliphatic nitrile is reduced to hydrogen to derive an aliphatic amine. It is preferable because it does not have an adverse effect.
[0010]
The niobium oxide used in the present invention includes niobium pentoxide, niobium tetroxide, niobium trioxide, niobium dioxide and niobium monoxide. Any niobium oxide can be used, but from the viewpoint of reactivity, pentoxide is used. Niobium is preferably used. The form of niobium oxide is not particularly limited, and a hydrated product or an anhydride may be used.
[0011]
The method for preparing niobium oxide treated with an acid used in the present invention is not particularly limited. For example, a method of suspending niobium oxide in an acid aqueous solution, followed by evaporation to dryness and baking is used. The suspension time of niobium oxide in the acid aqueous solution is not particularly limited, but the effect of activating the catalyst is greater when it is performed for 24 hours or more. Washing with water may or may not be performed, but if a large amount of acid remains, it is better to wash with water. Firing may or may not be performed, but when firing, the firing temperature is not particularly limited, but a temperature of 500 ° C. or lower is preferable. When calcination is performed at a temperature exceeding the above range, crystallization of the catalyst occurs, so that the surface area is reduced and the catalytic activity is lowered.
[0012]
In the method of the present invention, the reaction can be carried out in a batch, semi-batch, continuous, or fixed bed flow system using a suspension bed. The reaction temperature is preferably in the range of 180 to 350 ° C, more preferably 250 to 300 ° C. The reaction pressure is usually performed in a slightly pressurized state, but may be normal pressure. The amount of the niobium oxide catalyst treated with the acid is 0.1 to 10% by weight, preferably 0.3 to 3% by weight based on the lower alkyl ester of the carboxylic acid when carried out in a batch, semi-batch or continuous mode using a suspended bed. %. Moreover, when implementing by a fixed bed flow type, the average residence time in the catalyst layer of a reaction mixture has preferable 1 second-10 minutes.
[0013]
【The invention's effect】
The method of the present invention uses a highly active niobium oxide, which is obtained by treating niobium oxide with an acid and is hardly soluble in the reaction solution, as a catalyst. Therefore, an aliphatic nitrile of excellent quality can be produced in a high yield, which is extremely significant industrially.
[0014]
【Example】
Example 1
30.14 g of niobium pentoxide hydrate (manufactured by CBMM, water content 13.4 wt%) and 100 ml of 0.5 mol / L boric acid aqueous solution were added to the flask, and the mixture was stirred at room temperature for 48 hours, acid-treated, and then filtered with suction. The obtained catalyst precursor was stirred in 1000 ml of ion-exchanged water for 30 minutes and suction filtered. This washing with water was repeated three times, and then dried at 100 ° C., calcined at 300 ° C. for 3 hours, and a niobium oxide catalyst treated with boric acid was obtained.
[0015]
Next, 1.0 g of the catalyst and 500 g of methyl stearate were mixed in a four-necked flask equipped with a stirrer, a gas introduction tube, a thermometer, and a dehydrator, and 6 ml of ammonia gas of 1050 ml / min at 260 ° C. was mixed therewith. The reaction was introduced over time. The reaction product obtained by separating the catalyst was analyzed by gas chromatography [gas chromatograph: HEWLETT PACKARD Series 5890, column: J & W, DB-5 (inner diameter x length: 0.53 mm x 15 m)] Table 1 shows. As a result of elemental analysis by ICP emission analysis, boron and niobium in the reaction product were below the detection limit.
[0016]
Example 2
In preparing the catalyst, the same operation as in Example 1 was repeated except that hydrochloric acid was used instead of boric acid to obtain a niobium oxide catalyst treated with hydrochloric acid. The reaction was carried out under the same conditions as in Example 1 using the catalyst. The reaction product was analyzed as in Example 1. The results are shown in Table 1. Chlorine and niobium in the reaction product were below the detection limit.
[0017]
Comparative Example 1
For comparison, the reaction was carried out in the same manner as in Example 1 using niobium pentoxide that was not treated with acid as a catalyst. The reaction product was analyzed as in Example 1. The results are shown in Table 1.
[0018]
Examples 3-5
A niobium oxide catalyst treated with boric acid was obtained by repeating the same operation as in Example 1 except that the boric acid concentration was changed to the concentration shown in Table 1 in the catalyst preparation. The reaction was carried out under the same conditions as in Example 1 using the catalyst. The reaction product was analyzed as in Example 1. The results are shown in Table 1. In either case, boron and niobium were not detected in the reaction product.
[0019]
Examples 6-7
The reaction was performed in the same manner as in Example 1 except that the catalyst prepared in Example 1 was used and the reaction temperature and reaction time were changed to the values shown in Table 1. The reaction product was analyzed as in Example 1. The results are shown in Table 1. In either case, boron and niobium were not detected in the reaction product.
[0020]
[Table 1]

[0021]
Example 8
Using the catalyst prepared in Example 1, the reaction was conducted in the same manner as in Example 1 except that methyl laurate was used instead of methyl stearate. As a result of analyzing the reaction product in the same manner as in Example 1, the production amount of lauronitrile was 87.3 (GC%), and boron and niobium were not detected in the reaction product.
[0022]
Example 9
The niobium oxide powder treated with boric acid before calcination prepared by repeating the same operation as in Example 1 was extruded and then calcined at 300 ° C. for 3 hours to obtain a molded catalyst. 1.0 g of the catalyst was packed in the center of a stainless steel cylindrical reaction tube having an inner diameter of 10 mm and a length of 500 mm. Ammonia gas was supplied from the upper part of the reaction tube at a rate of 88.3 L / hr and methyl stearate at a rate of 1.5 g / hr, and reacted at 260 ° C. under normal pressure. The obtained reaction product was subjected to gas-liquid separation treatment, and the amount of stearonitrile produced was measured by gas chromatography in the same manner as in Example 1. As a result, it was 99.2 (GC%). Further, boron and niobium in the reaction product were below the detection limit.

Claims (4)

A method for producing an aliphatic nitrile, comprising reacting an aliphatic carboxylic acid lower alkyl ester with ammonia in the presence of an acid-treated niobium oxide.  The method for producing an aliphatic nitrile according to claim 1, wherein niobium oxide treated with an acid aqueous solution having a concentration of 0.1 to 5 mol / L is used. The method for producing an aliphatic nitrile according to claim 1 or 2, wherein the acid is hydrochloric acid or boric acid. The method for producing an aliphatic nitrile according to any one of claims 1 to 3, wherein the aliphatic carboxylic acid lower alkyl ester is a methyl ester of an aliphatic carboxylic acid having 6 to 22 carbon atoms.