JP4219484B2 - Method for producing aliphatic nitrile - Google Patents

Description

【００１８】
実施例１１
実施例２で調製した酸化チタンとシリカの重量比が95：５の複合酸化物触媒を使用して、ステアリン酸メチルの代わりにラウリン酸メチルを使用した以外は実施例１と同一条件で反応を行なった。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86.3（GC％）であり、また反応生成物中のチタン及び珪素は検出限界以下であった。
【００１９】
実施例１２
酸化チタンとシリカの重量比が95：５となるように、実施例２と同様の操作を繰り返して焼成前の粉末を調製した。その粉末を押し出し成形後、 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927 mL/hr 、ステアリン酸メチルを1.2g/hr の速度で反応管の上部から供給し、 250℃、常圧下で反応させた。得られた反応生成物は気液分離及び脱水処理し、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、98.9（GC％）であった。また反応生成物中のチタン及び珪素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 gas phase reaction, dehydration of 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, titanium oxide, etc. A method in which a previously vaporized aliphatic carboxylic acid or a derivative thereof is contacted with ammonia at a temperature of 250 to 600 ° C. is carried out using a catalyst having an action. 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 with high yield and high quality at low cost without dissolution.
[0005]
[Means for Solving the Problems]
The present inventors have found that the composite oxide catalyst mainly composed of titanium oxide has a high catalytic activity even at a reaction temperature of 300 ° C. or less and is a solid that is hardly soluble in the reaction solution, and has completed the present invention. It came to do.
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 a composite oxide catalyst mainly composed of titanium oxide.
[0006]
In the present invention, the “composite oxide” is an oxide in which two or more metals coexist inside or on the surface.
[0007]
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.
[0008]
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.
[0009]
The catalyst used in the method of the present invention is a composite oxide catalyst containing titanium oxide as a main component, and the titanium oxide includes at least one selected from the group consisting of silicon, niobium, zirconium, tantalum, gallium and germanium. A composite oxide catalyst in which an oxide of an element is combined is preferable, and a composite oxide catalyst in which silica, niobium oxide or zirconium oxide is combined with titanium oxide is particularly preferable. The content of oxides other than titanium oxide in the composite oxide catalyst of the present invention is preferably 1 to 25% by weight, and more preferably 1 to 15% by weight in that high activity is obtained.
[0010]
The method for preparing the catalyst used in the method of the present invention is not particularly limited, but a method in which titanium oxide and another oxide form a composite, for example, a deposition method, a coprecipitation method, an alkoxide method, an impregnation method, etc. Used. There are no particular restrictions on the calcination temperature of the catalyst, but it is preferably carried out at 500 ° C. or lower. When calcined at a temperature exceeding 500 ° C., the surface area of the catalyst is reduced and the activity is lowered.
[0011]
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 pressure during the reaction is usually performed in a slightly pressurized state, but may be normal pressure. The amount of the composite oxide catalyst used is preferably 0.1 to 10% by weight, more preferably 0.3%, based on the aliphatic carboxylic acid lower alkyl ester when the batch, semi-batch, or continuous system is used. ~ 3 wt%. 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.
[0012]
【The invention's effect】
The method of the present invention uses a complex oxide catalyst that is highly active and hardly soluble in the reaction solution, so that compared with the conventional method, there is no dissolution of the catalyst in the product, and an excellent quality aliphatic nitrile. Can be produced in a high yield and is extremely significant industrially.
[0013]
【Example】
Examples 1-4, Comparative Examples 1-3
The flask was charged with titanium tetraisopropoxide, tetraethyl orthosilicate and isopropanol as a solvent so that the weight ratio of titanium oxide and silica was as shown in Table 1. After raising the temperature to 80 ° C., 6 mol times of ion-exchanged water was added dropwise to the metal alkoxide with stirring. After completion of the dropwise addition, stirring was continued at that temperature for 5 hours. The catalyst precursor taken out by filtration was washed with ion-exchanged water, filtered, dried at 110 ° C., and calcined at 300 ° C. for 3 hours to obtain a composite oxide catalyst used in the present invention.
[0014]
Next, 5.0 g of the composite oxide 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 1100 ml / min of ammonia gas was added at 260 ° C. The reaction was introduced over 6 hours. The resulting reaction product was subjected to composition analysis by gas chromatography [gas chromatography device: HEWLETT PACKARD Series 5890, column: J & W DB-5 (inner diameter x length: 0.53 mm x 15 m)], and the amount of nitrile produced was measured. . For comparison, the same applies to titanium oxide and silica each prepared by repeating the same operation as described above, or a catalyst having a titanium oxide: silica weight ratio of 95: 5 obtained by physically mixing them. The reaction was conducted under conditions. The results are shown in Table 1. When the catalyst of the present invention was used, the progress of the reaction was fast, and as a result of elemental analysis by ICP emission analysis, titanium and silicon in the reaction product were below the detection limit.
[0015]
Examples 5-9
In the catalyst preparation, the same operation as in Example 2 was performed except that zirconium tetrapropoxide, niobium pentaethoxide, tantalum pentaethoxide, gallium triisopropoxide, or germanium tetraethoxide was used instead of tetraethyl orthosilicate. Repeatedly, a composite oxide catalyst was obtained. Using the composite oxide catalyst, the reaction was carried out under the same conditions as in Example 1, and the reaction products were analyzed in the same manner as in Example 1. The results are shown in Table 1. The metal element derived from the catalyst in the reaction product was below the detection limit.
[0016]
Example 10
The same conditions as in Example 1 except that ammonia gas was introduced over 3 hours at a reaction temperature of 300 ° C. using the composite oxide catalyst having a weight ratio of 95: 5 of titanium oxide and silica prepared in Example 2. The reaction was carried out. The reaction product was analyzed as in Example 1. The results are shown in Table 1. Titanium and silicon in the reaction product were below the detection limit.
[0017]
[Table 1]

[0018]
Example 11
The reaction was carried out under the same conditions as in Example 1 except that methyl laurate was used instead of methyl stearate using the composite oxide catalyst prepared in Example 2 with a weight ratio of titanium oxide to silica of 95: 5. I did it. As a result of analyzing the reaction product in the same manner as in Example 1, the production amount of lauronitrile was 86.3 (GC%), and titanium and silicon in the reaction product were below the detection limit.
[0019]
Example 12
The same operation as in Example 2 was repeated to prepare a powder before firing so that the weight ratio of titanium oxide to silica was 95: 5. The powder was extruded and 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 927 mL / hr and methyl stearate at a rate of 1.2 g / hr, and reacted at 250 ° C. under normal pressure. The obtained reaction product was subjected to gas-liquid separation and dehydration treatment, and then the amount of stearonitrile produced was measured by gas chromatography in the same manner as in Example 1. As a result, it was 98.9 (GC%). Further, titanium and silicon in the reaction product were below the detection limit.

Claims (3)

A method for producing an aliphatic nitrile, wherein an aliphatic carboxylic acid lower alkyl ester and ammonia are reacted in the presence of a composite oxide catalyst mainly composed of titanium oxide. 2. The method for producing an aliphatic nitrile according to claim 1, wherein the oxide compounded with titanium oxide is an oxide of one or more elements selected from the group consisting of silicon, niobium, zirconium, tantalum, gallium and germanium. The method for producing an aliphatic nitrile according to claim 1 or 2, wherein the lower alkyl ester of the aliphatic carboxylic acid is a methyl ester of a carboxylic acid having 6 to 22 carbon atoms.