JP3872268B2 - Production process of hydrogen cyanide - Google Patents

Description

【００４６】
【発明の効果】
本発明のシアン化水素の製法は、高いシアン化水素収率を与えると共に、触媒構造が安定なものであるため、反応の経時安定性が向上し、モリブデン成分を補給添加する事により長期にわたり触媒性能維持が可能である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalyst and a reaction method suitable for producing hydrogen cyanide by ammoxidation of methanol.
[0002]
[Prior art]
Regarding the production of hydrogen cyanide by ammoxidation of methanol, various catalysts have been disclosed as suitable catalysts. For example, Japanese Patent Publication No. 37-13460 discloses an oxide catalyst containing tin and antimony, Japanese Patent Publication No. 51-35400 discloses a composite oxide catalyst of molybdenum and many other elements, and Japanese Patent Publication No. 54-39839. The publication discloses an oxide catalyst containing metal elements such as iron, cobalt, nickel and antimony.
[0003]
Thereafter, the improvement of these catalysts continued energetically, and for example, improved patents such as JP-B 61-4771, JP-B 63-16330 and JP-A-4-118051 have been disclosed.
[0004]
[Problems to be solved by the invention]
Although these prior art catalysts were effective in improving the hydrogen cyanide yield as such, further improvements have been demanded, particularly for catalysts with a high molybdenum content, the initial yield of hydrogen cyanide was good. However, it is still insufficient in terms of reproducibility in catalyst production, structural stability, or a stable reaction over a long period of time.
[0005]
For this reason, there has been a demand for a catalyst that can provide a good hydrogen cyanide yield and satisfy the requirements of being stable over time when used in a reaction. The present invention is intended to solve these problems. In particular, a catalyst having a high molybdenum content is improved as a catalyst suitable for producing hydrogen cyanide by ammoxidation reaction of methanol using a fluidized bed.
[0006]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention are composed of elements such as iron, antimony, molybdenum, bismuth, and potassium, contain iron antimonate, and have a limited composition region catalyst. It has been found that it has good performance and can maintain its performance for a long period of time by reacting while appropriately adding a molybdenum-containing material thereto.
[0007]
This catalyst composition provides a high hydrogen cyanide yield and is stable as a catalyst structure. However, when this catalyst continues to react, a decrease in the yield of hydrogen cyanide, which is thought to be mainly due to the escape of the molybdenum component, is observed. The reaction temperature of the ammoxidation reaction exceeds 400 ° C., and this type of catalyst with a high molybdenum content is considered to be unavoidable. It was possible to maintain a high hydrogen cyanide yield for a long period of time by reacting while adding and replenishing molybdenum-containing material. The catalyst of the present invention is structurally stable, and the recovery of the reaction results can be sufficiently achieved by adding molybdenum-containing materials, and this can be repeatedly applied. Became possible.
[0008]
The addition of the molybdenum-containing material may be performed at the initial stage of the reaction. The catalyst is generally used for the reaction by optimizing the composition and structure of the catalyst surface according to the composition, preparation method, etc., but this is not always realized. When the molybdenum-containing material is first added and reacted, the target product yield may be increased. This is thought to be the result of optimization of the composition and structure of the catalyst surface, including the addition of molybdenum-containing material.
[0009]
As described above, the conventional catalyst has an insufficient hydrogen cyanide yield, and when the yield is lowered by long-term use, the performance recovery is insufficient even when a molybdenum-containing material is added. Provided a method capable of maintaining a high hydrogen cyanide yield over a long period of time.
[0010]
That is, in the present invention, when producing hydrogen cyanide by ammoxidation of methanol, a fluidized bed catalyst having a composition represented by the following empirical formula is used, and a molybdenum-containing material is added in the production. The present invention relates to a process for producing hydrogen cyanide, which is characterized in that the reaction is carried out while carrying out the reaction.
Fea Sbb Moc Bid Ke Ff Gg Hh Qq Rr Tt Ox (SiO2) y
(Wherein Fe, Sb, Mo, Bi and K represent iron, antimony, molybdenum, bismuth and potassium, respectively, and F represents a group consisting of magnesium, calcium, strontium, barium, manganese, cobalt, nickel, zinc and cadmium. At least one element selected, G is at least one element selected from the group consisting of chromium, aluminum, gallium and indium, H is at least one element selected from the group consisting of lanthanum, cerium, praseodymium, neodymium and samarium Element, Q is at least one element selected from the group consisting of titanium, zirconium, vanadium, niobium, tantalum, tungsten, germanium, tin and lead, R is at least selected from the group consisting of lithium, sodium, rubidium and cesium A kind of element, T is boron, phosphorus and And at least one element selected from the group consisting of tellurium, O is oxygen, Si is silicon, and the suffixes a, b, c, d, e, f, g, h, q, r, t, x and y Indicates an atomic ratio, when a = 10, b = 5 to 60, c = 5 to 50, d = 0.15 to 5, e = 0.1 to 5, f = 2 to 35, g = 0.05 to 10, h = 0.05-10, h / c> 0.02, q = 0-10, r = 0-5, t = 0-5, x = number of oxygen in the metal oxide produced by combining the above components, y = 20 ˜500 and iron antimonate is present as a crystalline phase.)
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described more specifically.
The fluidized bed catalyst used in the present invention is essential to contain iron, antimony, molybdenum, bismuth, potassium, F component, G component, H component, silica, and iron antimonate as a crystalline phase, If the component is not within the predetermined range, the object of the present invention cannot be achieved. Iron antimonate is a compound represented by the chemical formula of FeSbO4 described in JP-A-4-18051, JP-A-10-231125, and the like, and its presence can be confirmed by X-ray diffraction of the catalyst. Iron antimonate is essential for improving the yield of hydrogen cyanide and improving the physical properties of the catalyst. It has been found that bismuth is essential for providing a catalyst having a high hydrogen cyanide yield and good stability, and there is a preferable composition region therefor. If the amount of potassium is too small, by-products increase and the hydrogen cyanide yield decreases. If the amount is too large, the reaction rate decreases, and the hydrogen cyanide yield decreases. F, G and H components contribute to the stabilization of the catalyst structure. If the addition amount is too small, the catalyst structure becomes unstable, and it becomes difficult to maintain a good hydrogen cyanide yield over a long period of time. If the amount added is too large, the hydrogen cyanide yield decreases.
[0012]
As the catalyst component, the above Q, R and T components can be further added. These are added as necessary for the purpose of stabilizing the catalyst structure, improving redox characteristics, adjusting acid and basicity, and the like. As the Q component, zirconium, vanadium, niobium, tungsten and the like are preferable, and as the R component, sodium, rubidium, cesium and the like are preferable. A small amount of T component is added as necessary for the purpose of improving hydrogen cyanide selectivity and adjusting by-products.
[0013]
The method of the present invention is carried out by a fluidized bed reaction. Therefore, the catalyst needs to have physical properties suitable for a fluidized bed reaction. Therefore, silica is used as the carrier component.
[0014]
As a method for preparing the catalyst of the present invention, a method disclosed in the above-described prior art may be appropriately selected and applied.
[0015]
Various methods for preparing iron antimonate have been proposed. For example, there are methods described in JP-A-4-18051, JP-A-10-231125, etc., and these methods may be selected and used. In the production of the catalyst of the present invention, it is important that iron antimonate is prepared in advance by these methods and then mixed with other catalyst component raw materials. The presence of iron antimonate contributes to improved hydrogen cyanide selectivity and improved physical properties as a fluidized bed catalyst.
[0016]
Molybdenum component materials include molybdenum oxide, ammonium paramolybdate, etc., bismuth component materials include bismuth oxide, bismuth nitrate, bismuth carbonate, bismuth oxalate, etc., and iron component materials include iron nitrate, iron oxalate, etc. However, potassium nitrate, potassium hydroxide, and the like are used as the potassium component raw material, and oxides, hydroxides, nitrates, and the like are used as the F, G, and R component raw materials. As H component raw materials, respective oxides, hydroxides, nitrates, oxygen acids or salts thereof, etc., as T component raw materials, boric acid, boric anhydride, etc. in the case of boron, orthophosphoric acid, etc. in the case of phosphorus, In the case of tellurium, metal tellurium, tellurium dioxide, tellurium trioxide, telluric acid and the like are used. As the silica raw material, silica sol, fumed silica or the like is used, but it is convenient to use silica sol.
[0017]
Iron antimonate is mixed with other ingredients to prepare a slurry. The catalyst raw materials are mixed, the pH of the slurry is adjusted as necessary, and heat treatment is added to prepare a catalyst slurry. When manufacturing by adjusting the pH to 3 to 8 which is relatively high, chelating agents such as ethylenediaminetetraacetic acid, lactic acid, citric acid, tartaric acid, gluconic acid are used in accordance with the method described in Japanese Patent No. 2747920 for the purpose of suppressing gelation of the slurry. Etc. should coexist. In the case of producing by adjusting the pH to 1 to 3 which is relatively low, the coexistence of the chelating agent is not necessarily required, but good results may be obtained by adding a small amount.
[0018]
The slurry thus prepared is spray dried. The spray drying device may be a general device such as a rotary disk type or a nozzle type. The conditions are adjusted so that a catalyst having a preferable particle size as a fluidized bed catalyst can be obtained. After drying, it is fired at 200 to 500 ° C., and further fired at 500 to 700 ° C. for 0.1 to 20 hours. The firing atmosphere is preferably an oxygen-containing gas. Although it is convenient to carry out in air, a mixture of oxygen and nitrogen, carbon dioxide, water vapor or the like can also be used. A box furnace, tunnel furnace, rotary furnace, fluidized furnace, or the like is used for firing.
[0019]
The particle size of the fluidized bed catalyst thus produced is preferably 5 to 200 μm. When using a molybdenum-containing fluidized bed catalyst for the production of hydrogen cyanide, a method for maintaining the yield of the target product by adding a molybdenum-containing material during the reaction as described above is known. However, unless it is applied to a catalyst having a stable catalyst structure, the effect cannot be sufficiently expected. Since the catalyst of the present invention is structurally robust even when used for a long period of time at a temperature exceeding 400 ° C. at which this kind of reaction is performed, the addition of a molybdenum-containing material causes a reaction equivalent to or higher than the initial reaction. The reaction can be continued while maintaining the results. Even with such a structurally stable catalyst, the molybdenum component gradually evaporates from the catalyst under the reaction conditions, and it is likely that the catalyst structure will be damaged, and the molybdenum content is added before this becomes critical. It is necessary to. The molybdenum-containing material used here is metal molybdenum, molybdenum trioxide, molybdic acid, ammonium dimolybdate, ammonium paramolybdate, ammonium octamolybdate, ammonium dodecamolybdate, phosphomolybdic acid, or these molybdenum-containing materials. It may be used by being supported on an inert substance or a catalyst. Although it can be used in the form of gas or liquid, it is practical to use these solid molybdenum components as powder.
[0020]
In particular, a method using a molybdenum component enriched in a catalyst is effective. This method is a preferred mode of use because the use efficiency of the added molybdenum is good and troubles due to precipitation of molybdenum oxide in the system are suppressed. The method described in Japanese Patent Publication No. 2-56939 or Japanese Patent Application Laid-Open No. 11-33400 can be applied to the production method of the molybdenum-enriched catalyst.
[0021]
These molybdenum-containing materials are continuously or intermittently added to the reactor from time to time. The addition timing and addition amount may be appropriately determined from the relationship between the transition of the reaction and the operability, but the addition amount at a time is preferably in the range of 0.05 to 2% by weight as molybdenum with respect to the packed catalyst. Even if a large amount is added at a time, it will escape to the outside of the reaction system and will be consumed wastefully, and will be deposited and deposited in the reactor, or will adhere to the heat exchanger and cause operational problems. So be careful.
[0022]
Ammoxidation of methanol is usually performed using a feed gas having a composition range of methanol / ammonia / oxygen of 1 / 0.9 to 1.3 / 0.8 to 10 (molar ratio) at a reaction temperature of 370 to 500 ° C. and a reaction pressure of normal pressure to 500 kPa. Do. Apparent contact time is 0.1-20 seconds. As the oxygen source, it is convenient to use air, but this may be diluted with water vapor, carbon dioxide gas, saturated hydrocarbon or the like, or may be enriched with oxygen.
[0023]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
[0024]
Catalyst activity test Hydrogen cyanide synthesis by ammoxidation of methanol was performed to evaluate the activity of the catalyst.
The catalyst is packed in a fluidized bed reactor with an inner diameter of 25 mm and a height of 400 mm, and a mixed gas of methanol / ammonia / air = 1 / 1.2 / 9.5 (2.0 as oxygen) is gas linear velocity. It was sent at 4.5cm / sec. The reaction pressure was 100 kPa.
In addition, the molybdenum containing material was added suitably at the time of reaction. For the molybdenum-containing material, 0.1 to 0.2% by weight of molybdenum was added at intervals of 50 to 150 hours with respect to the packed catalyst using several molybdenum compounds and a catalyst enriched with the molybdenum component.
[0025]
The contact time and hydrogen cyanide yield in Examples and Comparative Examples are defined as follows.
Contact time (sec) = catalyst volume based on apparent bulk density (ml) / supply gas flow rate converted to reaction conditions (ml / sec)
Hydrogen cyanide yield (%) = number of moles of hydrogen cyanide produced / number of moles of methanol supplied x 100
[0026]
Example 1
Composition is Fe10 Sb9.2 Mo15 Bi0.6 K0.3 Co2.25 Ni6 Cr1.2 Ce0.6 P0.3B0.3Ox (SiO2) 55 (The atomic ratio x of oxygen is naturally determined by the valence of other elements Since this is a value, the description of the atomic ratio of oxygen is omitted hereinafter).
Dissolve 304.9 g of ammonium paramolybdate in 3000 g of pure water, then add 2.9 g of 85% phosphoric acid and 1.2 g of boric anhydride. A solution prepared by dissolving 33.5 g of bismuth nitrate, 3.5 g of potassium nitrate, 75.4 g of cobalt nitrate, 200.9 g of nickel nitrate, 55.3 g of chromium nitrate, 30 g of cerium nitrate, and 24.9 g of citric acid was mixed with 270 g of 3.3% nitric acid. Separately, a solution in which 76.8 g of iron nitrate and 25 g of citric acid were dissolved in 270 g of pure water was prepared and added thereto. Then 1902.5 g of 20% silica sol was added. While stirring the slurry, 15% aqueous ammonia was added to adjust the pH to 2. This was heat-treated at 98 ° C. for 1.5 hours. Further, 1198.5 g of 20% iron antimonate slurry prepared separately was added.
[0027]
The slurry thus prepared was spray-dried with a rotary disk spray dryer at an inlet temperature of 330 ° C. and an outlet temperature of 160 ° C. The dried particles were heat-treated at 250 ° C. for 2 hours and 400 ° C. for 2 hours, and finally fluidized and fired at 670 ° C. for 3 hours.
In addition, the iron antimonate slurry used here was prepared as follows.
Nitric acid (65% by weight) 1815 g and pure water 1006 g are mixed, and electrolytic iron powder 218 g is added little by little. After the iron powder was completely dissolved, 625 g of antimony trioxide powder was mixed, and 10% ammonia water was added dropwise with stirring to adjust the pH to 1.8. The slurry was heated at 98 ° C. for 3 hours with stirring. The slurry was dried with a spray dryer at an inlet temperature of 330 ° C. and an outlet temperature of 160 ° C., and then calcined at 250 ° C. for 2 hours and at 400 ° C. for 2 hours. Further, calcination was performed at 850 ° C. for 3 hours in a nitrogen stream. After firing, it was pulverized and mixed with pure water to obtain a 20% iron antimonate slurry. In the following examples and comparative examples, the iron antimonate slurry thus prepared was used.
[0028]
Example 2
A catalyst having a composition of Fe10 Sb9.2 Mo15 Bi0.6 K0.3 Ni8.25 Cr0.75 Ga0.45 Ce0.6 P0.3 (SiO2) 55 was prepared in the same manner as in Example 1. However, gallium nitrate was used as the gallium raw material, and the final firing temperature was 530 ° C.
[0029]
Example 3
Catalyst with composition Fe10 Sb8.6 Mo20 Bi0.8 K0.4 Ni8 Ca0.6 Zn0.4 Cr2.4 Al0.2 In0.2 La0.2 Ce0.6 Ge0.4 B0.4 (SiO2) 70 Prepared in the same manner as in Example 1. However, each nitrate was used as a raw material for Ca, Zn, Al, In, La, and Ge, and the final firing temperature was 540 ° C.
[0030]
Example 4
A catalyst having a composition of Fe10 Sb8.0 Mo25 Bi1.25 K0.75 Ni12.5 Mg2.5 Cr1 Ce1 Pr0.25 (SiO2) 100 was prepared in the same manner as in Example 1. However, each nitrate was used as a raw material for Mg and Pr, and the final firing temperature was 560 ° C.
[0031]
Example 5
A catalyst having a composition of Fe10 Sb6.9 Mo25 Bi1.25 K0.5 Ni12.5 Cr1.75 Ce1.25 Rb0.25 P0.25 B0.25 (SiO2) 90 was prepared as follows.
Dissolve 352.8 g of ammonium paramolybdate in 3000 g of pure water, then add 2.3 g of 85% phosphoric acid and 1.2 g of boric anhydride. This solution was mixed with 270 g of 3.3% nitric acid in which bismuth nitrate 48.5 g, potassium nitrate 4.0 g, nickel nitrate 290.5 g, chromium nitrate 56.0 g, cerium nitrate 43.4 g, rubidium nitrate 2.9 g, and citric acid 25 g were dissolved. Next, 2161.1 g of 20% silica sol was added, and 15% aqueous ammonia was added dropwise with stirring to adjust the pH to 7.7.
This was heat-treated at 98 ° C. for 1.5 hours. Separately, a solution prepared by dissolving 121.1 g of iron nitrate and 25 g of citric acid in 270 g of pure water was added to the slurry after the heat treatment, and 623.5 g of 20% iron antimonate slurry prepared separately was further added.
[0032]
The slurry thus prepared was spray-dried with a rotary disk spray dryer at an inlet temperature of 330 ° C. and an outlet temperature of 160 ° C. The dried particles were heat-treated at 250 ° C. for 2 hours and 400 ° C. for 2 hours, and finally fluidized and fired at 560 ° C. for 3 hours.
[0033]
Example 6
A catalyst having a composition of Fe10 Sb7.7 Mo30 Bi1.2 K0.9 Ni16.5 Cr1.2 Ce2.4 W1.5P0.6 (SiO2) 110 was prepared as follows.
In 3000 g of pure water, 25.5 g of ammonium paratungstate was dissolved, and then 344.8 g of ammonium paramolybdate was mixed and dissolved, and 4.5 g of 85% phosphoric acid was further added. A solution prepared by dissolving 37.9 g of bismuth nitrate, 5.9 g of potassium nitrate, 312.4 g of nickel nitrate, 31.3 g of chromium nitrate, 67.8 g of cerium nitrate, and 25 g of citric acid was mixed with 270 g of 3.3% nitric acid. Next, 2151.7 g of 20% silica sol was mixed. While stirring the slurry, 15% aqueous ammonia was added dropwise to adjust the pH to 5. This was heat-treated at 98 ° C. for 1.5 hours under reflux. Separately, a solution prepared by dissolving 78.9 g of iron nitrate and 25 g of citric acid in 270 g of pure water was added to the slurry after the heat treatment, and 567.5 g of 20% iron antimonate slurry prepared separately was further added.
[0034]
The slurry thus prepared was spray-dried with a rotary disk spray dryer under conditions of an inlet temperature of 330 ° C. and an outlet temperature of 160 ° C. The dried particles were heat-treated at 250 ° C. for 2 hours and at 400 ° C. for 2 hours, and finally fluidized and fired at 570 ° C. for 3 hours.
[0035]
Example 7
A catalyst having a composition of Fe10 Sb4.4 Mo30 Bi1.2 K0.6 Mg3 Ni10.5 Mn1.5 Cr1.2 Ce1.2 Nb0.3 (SiO2) 150 was prepared in the same manner as in Example 6. However, the Mg and Mn raw materials were nitrates, the Nb raw materials were niobium hydrogen oxalate, and the final firing temperature was 530 ° C.
[0036]
Example 8
A catalyst having a composition of Fe10 Sb7.4 Mo30 Bi1.5 K0.6 Co3 Ni13.5 Cr2.4 Ce2.1 Cs0.3 P0.3 (SiO2) 120 was prepared in the same manner as in Example 6. However, nitrate was used as a raw material for Co and Cs, and the final firing temperature was 520 ° C.
[0037]
Example 9
A catalyst having a composition of Fe10 Sb7.2 Mo35 Bi1.4 K1.05 Ni21 Cr2.45 Ce1.4 Nd0.35 Zr0.7 P0.7 (SiO2) 125 was prepared in the same manner as in Example 6. However, nitrate was used for the Nd raw material, zirconium oxynitrate was used for Zr, and the final firing temperature was 510 ° C.
[0038]
Example 10
A catalyst having a composition of Fe10 Sb7.5 Mo40 Bi2 K1 Ni24 Cr2.8 Ce1.6 Sm0.4 V0.4 Te0.8 (SiO2) 140 was prepared in the same manner as in Example 6. However, nitrate was used as the Sm raw material, ammonium metavanadate was used as the V raw material, telluric acid was used as the Te raw material, and the final firing temperature was 540 ° C.
[0039]
Comparative Example 1
A catalyst having a composition of Fe10 Sb9.2 Mo15 Bi0.6 K0.3 Ni8.25 P0.3 (SiO2) 55 was prepared in the same manner as in Example 1.
[0040]
Comparative Example 2
A catalyst having a composition of Fe10 Sb9.2 Mo15 Bi0.6 K0.3 Ni8.25 La0.3 Ce0.6 P0.3 O90.1 (SiO2) 55 was prepared in the same manner as in Example 1. However, nitrate was used as the La raw material, and the final firing temperature was 530 ° C.
[0041]
Comparative Example 3
A catalyst having a composition of Fe10 Sb7.4 Mo30 Bi1.5 K0.6 Co3 Ni13.5 Cr2.4 P0.3 (SiO2) 110 was prepared in the same manner as in Example 6. However, nitrate was used as the Co raw material.
[0042]
Comparative Example 4
A catalyst having a composition of Fe10 Sb7.4 Mo30 Bi1.5 K0.6 Co3 Ni13.5 Cr2.4 Ce0.3 P0.3 (SiO2) 110 was prepared in the same manner as in Example 6. However, nitrate was used as the Co raw material, and the final firing temperature was 530 ° C.
[0043]
The molybdenum-enriched catalysts used in Examples 7 to 10 and Comparative Examples 3 to 4 were prepared by impregnating an ammonium paramolybdate aqueous solution based on each catalyst, followed by drying and firing.
[0044]
Using the catalysts of these Examples and Comparative Examples, methanol ammoxidation reaction was performed under the above reaction conditions.
The results are shown in the table below.
[0045]
[Table 1]

[0046]
【The invention's effect】
The hydrogen cyanide production method of the present invention provides a high yield of hydrogen cyanide and has a stable catalyst structure, so that the reaction stability over time is improved, and the catalyst performance can be maintained for a long time by replenishing and adding a molybdenum component. It is.

Claims (3)

A process for producing hydrogen cyanide, which comprises using a fluidized bed catalyst having a composition represented by the following empirical formula when producing hydrogen cyanide by ammoxidation of methanol.
Fea Sbb Moc Bid Ke Ff Gg Hh Qq Rr Tt Ox (SiO2) y
(Wherein Fe, Sb, Mo, Bi and K represent iron, antimony, molybdenum, bismuth and potassium, respectively, and F represents a group consisting of magnesium, calcium, strontium, barium, manganese, cobalt, nickel, zinc and cadmium. At least one element selected, G is at least one element selected from the group consisting of chromium, aluminum, gallium and indium, H is at least one element selected from the group consisting of lanthanum, cerium, praseodymium, neodymium and samarium Element, Q is at least one element selected from the group consisting of titanium, zirconium, vanadium, niobium, tantalum, tungsten, germanium, tin and lead, R is at least selected from the group consisting of lithium, sodium, rubidium and cesium A kind of element, T is boron, phosphorus and And at least one element selected from the group consisting of tellurium, O is oxygen, Si is silicon, and the suffixes a, b, c, d, e, f, g, h, q, r, t, x and y Indicates an atomic ratio, when a = 10, b = 5 to 60, c = 5 to 50, d = 0.15 to 5, e = 0.1 to 5, f = 2 to 35, g = 0.05 to 10, h = 0.05-10, h / c> 0.02, q = 0-10, r = 0-5, t = 0-5, x = number of oxygen in the metal oxide produced by combining the above components, y = 20 ˜500 and iron antimonate is present as a crystalline phase.) The process for producing hydrogen cyanide according to claim 1, wherein the reaction is carried out while adding a molybdenum-containing material. The method for producing hydrogen cyanide according to claim 2, wherein the molybdenum-containing material to be added is a molybdenum-enriched catalyst.