JPS6136737B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing the corresponding esters from nitriles. More particularly, it relates to a method for reacting a nitrile with water and an alcohol to directly produce the corresponding ester. Esters, especially acrylic esters and methacrylic acid methyl esters, are extremely useful substances industrially. For example, acrylic esters are widely used in fibers, paints, adhesives, etc., and methacrylic esters are widely used as raw materials for synthetic resins. . Methods for producing these carboxylic esters include methods for producing them from nitrile; for example, when producing acrylic esters from acrylonitrile, a liquid phase method in which acrylonitrile, alcohol, and sulfuric acid are reacted is generally used. This method involves first producing acrylamide sulfate from acrylonitrile, sulfuric acid, and water, and then adding alcohol to produce an acrylic ester, but it has the drawback that the reaction is divided into two stages. In addition, in this method, the sulfuric acid used is used in an amount equal to or more than the mole of acrylonitrile,
In addition, since highly concentrated sulfuric acid is applied at high temperatures, special consideration must be given to the material of the reactor. Furthermore, this reaction has problems such as a decrease in yield due to side reactions such as polymerization, and a large amount of ammonium sulfate by-product, which is of low economic value. Recently, as a method to solve these problems, a method described in JP-A-47-25120 has been proposed in which acrylic acid ester is synthesized from acrylonitrile in one step in the gas phase using a catalyst containing boron trioxide. It was done. This method is preferable in that there is no problem of ammonium sulfate by-products because it attempts to synthesize acrylic acid ester in one step by catalytically reacting acrylonitrile, water, and alcohol in the gas phase without using sulfuric acid. The conversion rate to acrylic acid ester is low and the catalyst activity is not satisfactory. In view of these circumstances, the present inventors have conducted various studies on catalysts for the method of directly producing the corresponding ester from nitrile, and have found that an oxide-based catalyst containing titanium or titanium and a specific metal element as an active ingredient can be used to directly produce the corresponding ester from nitrile. The present invention was achieved based on the discovery that the compound exhibits excellent activity for conversion to . That is, the present invention provides a method for producing an ester, in which a nitrile is reacted with water and alcohol to directly produce the corresponding ester, and the conversion rate of the nitrile is high and the selectivity to the ester is excellent. By using an oxide catalyst containing titanium or titanium and a specific metal element as an active ingredient,
It aims to achieve this purpose. The method for producing the corresponding esters from nitriles according to the invention comprises converting a mixture of nitriles and water and alcohols into titanium or titanium with copper, silver, gold,
Oxide system containing as an active ingredient at least one metal element selected from the group consisting of magnesium, zinc, tin, lead, zirconium, vanadium, antimony, bismuth, chromium, molybdenum, tungsten, manganese, iron, cobalt, and nickel. It is characterized by carrying out the reaction at a temperature of 100°C or higher in the presence of a catalyst. In the method of the present invention, an oxide catalyst containing titanium or titanium and the above-mentioned specific metal element as an active ingredient is effectively used, and the preferable ratio of the active ingredients in the latter catalyst is the above-mentioned atomic ratio of 1 part titanium to 1 part titanium. The total amount of specific metal elements is preferably 10 or less, more preferably 7 or less. The oxide catalyst used in the method of the present invention can be produced by any method known in this type of technical field. For example, in the case of a catalyst containing titanium and copper, copper salts such as copper nitrate and copper sulfate are added to the precipitate produced by neutralizing titanium tetrachloride with aqueous ammonia and an alkali is added to the aqueous solution. It can be manufactured by adding the oxide and the oxide, mixing well, and then molding and firing. In the case of a catalyst containing titanium and tungsten, ammonium tungstate is added to the precipitate produced by neutralizing titanium sulfate with aqueous ammonia and mixed well, then dried and calcined to thermally decompose the tungsten component into oxides. It can be manufactured by Note that the catalytic activity of the catalyst in the method of the present invention is improved by firing, so the catalyst raw material composition prepared to the desired composition is finally
It is preferable to use it after baking at a temperature of 0.5 to 750°C for 0.5 to 48 hours. The catalyst may be formed into any shape such as spheres or pellets. Also,
In the method of the present invention, the catalyst can also be supported on a carrier. Examples of carriers include α-
Alumina, carborundum, etc. are used. The starting materials for each component constituting the catalyst can be selected from among many types, such as oxides, hydroxides, chlorides, nitrates, and organic acid salts of each component. Further, materials that can be converted into hydroxides or oxides by chemical treatment, baking treatment, etc. can also be used. Although it is not clear what form the catalyst components are in in the catalyst produced in this way, it is thought to be an oxide, various hydrated oxides, or hydroxides. In the present invention, such a catalyst is referred to as an oxide catalyst. The reactants in the process of the invention are nitrile, water and alcohol. Examples of the nitrile include various nitriles such as acetonitrile, propionitrile, acrylonitrile, methacrylonitrile, benzonitrile, glycolonitrile, and lactonitrile. Further, examples of the alcohol include various alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and ter-butyl alcohol, and the alcohol is selected from these alcohols depending on the desired ester. The reaction in the method of the present invention can be carried out by either a gas phase method or a liquid phase method, but the gas phase method is preferred. The method can be carried out by any method such as a fixed bed method or a fluidized bed method. The amounts of nitrile, water and alcohol subjected to the reaction can be varied within a wide range;
The amount of water per mole is preferably 1 to 20 moles, preferably 1.5 to 10 moles, and the amount of alcohol is preferably 1 to 10 moles, preferably 1 to 5 moles. The reaction temperature is preferably 100°C or higher, preferably 150 to 400°C.
If the reaction temperature is less than 100°C, the reaction rate is too low to be practical. The space velocity of the reactant gas is 10~10000hr ^-1
It is preferable to contact the catalyst for 10 to 5000 hr ^-1 . Although it is generally sufficient to carry out the reaction under atmospheric pressure, it can also be carried out under elevated or reduced pressure if necessary. In addition, during the reaction, the reaction gas may be brought into contact with the catalyst under the conditions described above, but it is preferable to dilute the reaction gas with a gas that does not harm the reaction, such as an inert gas such as nitrogen, to suppress side reactions and prevent formation of It is good because it is effective in inhibiting polymerization of substances and improving conversion rate and selectivity. Hereinafter, the method of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited only to these Examples. The test method is as follows. Fill a reaction tube with an inner diameter of 17 mmφ with 50 ml of catalyst, and heat it to a predetermined temperature. A gas having the following composition is fed into the reactor at a predetermined space velocity. The reaction pressure is normal pressure. The reaction gas is analyzed and quantified using a gas chromatograph. Water/nitrile = 4 (mole ratio) Alcohol/nitrile = 3 (mole ratio) Nitrogen/nitrile = 5 (mole ratio) Preparation of catalyst The following catalysts 1 to 15 are the catalysts of the present invention, and 16 to 20 is a comparative catalyst for clarifying the significance of the present invention. Each catalyst was prepared as follows. Furthermore, assuming that the catalyst is in the form of an oxide, the catalyst composition is shown in an experimental formula. Catalyst 1 190 g of titanium tetrachloride was gradually added to 2000 ml of water. Next, this aqueous solution was heated to a temperature of 80°C, and then aqueous ammonia was added to it while stirring to neutralize it. The generated precipitate was separated and obtained, thoroughly washed with pure water, and then dried at 200° C. for 5 hours. Next, water was added to this dried product, mixed well, formed into pellets of 5 mm x 5 mm diameter, and then heated at 500℃ for 2 hours.
After firing for an hour, a TiO ₂ catalyst was obtained. Catalyst 2 After dissolving 50.0 g of copper sulfate CuSO ₄ .5H ₂ O in 400 ml of water, the temperature of the aqueous solution was brought to 70°C. To this was added 200 ml of an aqueous solution containing 30 g of sodium hydroxide. The generated precipitate was separated and obtained, thoroughly washed with pure water, and then dried at 200° C. for 5 hours.
() Titanium oxide was prepared using 190 g of titanium tetrachloride in the same manner as in Catalyst 1. () () and () and 100 g of water were mixed together and mixed well while heating, then formed into pellets of 5 mm x 5 mm diameter, dried and calcined at 400°C for 4 hours. _The experimental formula for the composition of _this catalyst is Ti ₁ Cu _0.2 O _2.2 . Catalyst 3: Mix 18.2 g of vanadium pentoxide, dried titanium oxide prepared using 19 g of titanium tetrachloride in the same manner as Catalyst 1, 150 ml of water, and 100 g of α-alumina powder as a carrier, and mix well while heating. Thereafter, it was molded into pellets of 5 mm x 5 mm diameter, dried, and calcined at 500°C for 2 hours. The experimental formula for the composition of this catalyst is Ti ₀ . ₁ V ₀ . ₂ O ₀ . ₇ −(α−
Al ₂ O ₃ ) becomes a catalyst. Catalyst 4 190g of titanium tetrachloride by the same method as catalyst 1
After thoroughly mixing the dried titanium oxide prepared using chromium nitrate (Cr(NO ₃ ) ₃ 9H ₂ O) and 150 ml of water, it was formed into pellets of 5 mm x 5 mmφ.
After drying, a Ti ₁ Cr _0.2 O _2.3 catalyst was obtained by calcining at 500 _{° C.} for 2 hours. Catalysts 5-15 Catalysts 5-15 were prepared in the same manner as Catalyst 4. The compositions and firing conditions of these catalysts are shown in the table. As raw materials, Ag is silver nitrate, Zn is zinc nitrate, Sb is antimony trioxide, W
is ammonium tungstate, Mo is ammonium molybdate, Zr is zirconium nitrate, Cu
is copper nitrate, Sn is tin oxide, Au is gold oxide, Mg is magnesium nitrate, Fe is iron nitrate, Pb is lead nitrate,
Cobalt nitrate was used for Co, bismuth nitrate was used for Bi, nickel nitrate was used for Ni, and manganese nitrate was used for Mn. Catalyst 16 18.2g of vanadium pentoxide with silica as a carrier.
Alumina powder (alumina content 26% by weight) 100g
Add a small amount of water to this, mix well, and form into pellets of 5 mm x 5 mm diameter. After drying,
It was calcined at ℃ for 2 hours to obtain a V ₂ O ₅ -(SiO ₂ .Al ₂ O ₃ ) catalyst. Catalyst 17 Dissolve ₈₀ g of chromium nitrate Cr (NO ₃ ) 3.9H ₂ O in 200 g of water, and add 100 g of α-alumina powder as a carrier to this.
g was added and mixed well. This was dried at 110°C for 8 hours and then fired at 500°C for 2 hours. Then,
Water was added and mixed, formed into pellets of 5 mm x 5 mm diameter, and dried to obtain a Cr ₂ O ₃ -(α-Al ₂ O ₃ ) catalyst. Catalysts 18-20 Catalysts 18-19 supported on silica-alumina were prepared in the same manner as Catalyst 17. The compositions and firing conditions of these catalysts are shown in the table. As raw materials, ammonium tungstate was used for W, and cobalt nitrate was used for Co. Activity tests were conducted on the catalysts 1 to 20 using the test method described above. The results are shown in the table. 【table】

Claims (1)

[Claims] 1. A mixture of nitrile, water and alcohol,
Titanium or titanium and copper, silver, gold, magnesium, zinc, tin, lead, zirconium, hanadium,
At a temperature of 100°C or higher in the presence of an oxide catalyst containing as an active ingredient at least one metal element selected from the group consisting of antimony, bismuth, chromium, molybdenum, tungsten, manganese, iron, cobalt and nickel. A method for producing a corresponding ester from a nitrile, characterized in that the reaction is carried out. 2. The corresponding ester is produced from the nitrile according to claim 1, which is reacted in the presence of a catalyst in which the ratio of active ingredients in the catalyst is 10% or less of the total amount of metal elements to 1% titanium in atomic ratio. How to manufacture.