JPH0128741B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [] BACKGROUND OF THE INVENTION The present invention relates to an improved process for ammoxidation of organic compounds. Many examples of ammoxidation reactions of organic compounds are known, but here we will focus on reactions using metal oxide catalysts at temperatures of 300°C to 600°C, and examples of organic compounds include saturated and unsaturated olefins, Examples include alcohols, aldehydes, alkyl-substituted aromatic hydrocarbons, and alkyl-substituted heterocyclic compounds having heteroelements such as nitrogen, oxygen, and sulfur. As catalysts, metal oxide catalysts containing molybdenum, bismuth, etc., and metal oxide catalysts containing antimony tin, iron, uranium, etc., are useful for ammoxidation of propylene, isobutene, methanol, etc., as reported in Japanese Patent Publication No. 1973. 5870 Publication, Special Publication No. 37-14075, Publication No. 39-19111, Publication No. 1911-1911, Publication No. 1911-13460
Publication No. 1977-24367, Japanese Patent Publication No. 1977-24367
Publication No. 58100, Japanese Unexamined Patent Publication No. 51-10200, Special Publication No. 1973
This is described in Publication No. 33888, Japanese Patent Publication No. 18014/1983, etc. The usefulness of metal oxide catalysts containing vanadium for the ammoxidation of alkyl-substituted aromatic hydrocarbons and alkyl-substituted heterocyclic compounds has been reported in Japanese Patent Publications No. 15689-1989 and 13378-1978, etc. It has been stated. In the ammoxidation reactions of these organic compounds, a decrease in activity is often observed during long-term reaction use, although the degree varies depending on the type of catalyst or the conditions under which it is used. Most of them are a decrease in the yield of the desired product due to a decrease in the selectivity of the desired product. There are various causes for this, and countermeasures are being considered from various angles. However, in each case, the cause is not necessarily clear, and countermeasures include changing the reaction conditions, partially or completely replacing the catalyst, or removing the deteriorated catalyst from the reactor and regenerating it. There are only methods proposed that are complicated and involve considerable economic loss. It would be very advantageous if the catalyst performance could be restored while the reaction was being carried out. [] Summary of the invention In order to solve the above-mentioned problems regarding these metal oxide catalysts, the present invention provides a tellurium component in the ammoxidation reaction zone of an organic compound and a tellurium-containing solid present together with the catalyst. The objective is to be achieved by transferring the tellurium component from the source tellurium-containing solid to the catalyst. Therefore, the ammoxidation method according to the present invention can be carried out at 300°C.
A method for carrying out amonoxidation of an organic compound using a catalyst at a temperature of from 500°C to 500°C, wherein the ammoxidation is carried out in the presence of a mixture of a metal oxide catalyst substantially free of tellurium and a tellurium-containing solid; It is characterized by: Effects According to the present invention, it is possible to improve the selectivity of a metal oxide catalyst to a target product, reduce changes over time, or improve the selectivity of a deteriorated catalyst to a target product. Surprisingly, it has been revealed that the method of the present invention is sufficiently effective when applied not only to tellurium-containing catalysts but also to non-tellurium-containing catalysts, and has a wide range of applications. The method of the present invention can be applied to both fixed beds and fluidized beds, but is particularly effective in fluidized beds. In the case of a fluidized bed, it is easy to take out a part of the catalyst or add the catalyst while the reaction is being carried out. This can be carried out either continuously or intermittently, is easy to operate, and is routinely carried out industrially. Therefore, it is possible and easy to add the tellurium-containing solid of the present invention while carrying out a flow reaction. this is,
As mentioned above, unlike the conventional catalyst regeneration method,
Since the process can be carried out while the reaction is being carried out, there is no need to extract the entire amount of the catalyst from the reactor, and since the process can be carried out while the reaction is being carried out, there is no loss due to production stoppage. Further, it is economical because there is no need to newly install a special supply device, unlike when introducing tellurium alone or a tellurium compound in the form of steam or mist. The effect of the present invention in which the tellurium-containing solid is included in the catalyst bed is great when the catalyst bed forms a fluidized bed. The reason why the fluidized bed is more effective than the fixed bed is not clear, but in the fixed bed, the tellurium component concentration deposited on the catalyst is distributed in the axial direction of the reactor, whereas in the case of the fluidized bed, the concentration of the tellurium component deposited on the catalyst is distributed. In this case, it may be important that the catalyst is well mixed in the reactor, so that the concentration of the tellurium component in the catalyst is averaged without large deviations. The mechanism by which the present invention exerts its effects is not necessarily clear. However, tellurium alone or part of the tellurium compound from the tellurium-containing solids present in the reaction zone migrates onto the catalyst, and this covers the active sites that produce catalyst byproducts, such as carbon dioxide, carbon monoxide, and hydrocyanic acid. It is presumed that by inhibiting the production of these compounds, the selectivity of the desired product will be relatively increased. The effect of the present invention appears quickly, and the effect is long-lasting. [] Detailed Description of the Invention 1 Metal Oxide Catalyst The metal oxide catalyst used here is a variety of ammoxidation catalysts for organic compounds that do not substantially contain tellurium, as shown in the above-mentioned patent publications, or improvements thereof. It is a catalyst. The method of the present invention includes:
It can be equally applied to these known tellurium-free metal oxide catalysts. Specifically, it contains at least one element selected from the group consisting of antimony, molybdenum, and panadium. Examples include metal oxide catalysts. More specifically, the catalyst in the present invention is selected from the following catalysts. These can be used as catalyst components, or as silica,
It may be supported on various carriers such as silica/alumina, alumina, silica/titania, and titania. (1) Sb ₁₀ AaBbCcOx (atomic ratio composition) A=Fe, Co, Ni, Mn, U, Ce, Sn, Cu B=V, Mo, W C=Mg, Ca, Sr, Ba, La, Ti, Zr ,Nb,
Ta, Cr, Re, Ru, Os, Rh, Ir, Pd,
Pt, Ag, Zn, Cd, B, Al, Ga, In, Tl,
Ge, Pb, P, As, Bi, S, Se a=1~10 b=0~5 c=0~10 (2) Mo ₁₀ DdEeFfOx (atomic ratio composition) D=Fe, Ni, Co, Mn, Cr , Mg, Ca, Cu,
Zn, La, Ce, Al, Sn E=Sb, Bi, As, P, B F=K, Rb, Cs d=0~10 e=0.1~10 f=0~3 (3) V ₁₀ GgHhOx G= Li, Na, K, Rb, Cs, Tl, Mg, Ca,
Sr, Ba H=La, Ce, Ti, Zr, Nb, Ta, Cr, Mo,
W, Mn, Re, Fe, Ru, Os, Co, Rh,
Ir, Ni, Pd, Pt, Cu, Ag, Zn, Cd, B,
Al, Ga, In, Ge, Sn, Pb, P, As,
Sb, Bi, S, Se g=0~5 h=0~10 Note that O represents oxygen, and the subscript x indicates the number of oxygen corresponding to the oxide produced by combining each component element (see above) (1) to (3) common). The shape of the catalyst can be arbitrary, but in the case of a fixed bed reaction, catalysts in the shape of pellets, balls, etc. of several millimeters are used. In the case of fluidized bed reaction, the particle size is between 5 and 200.
Catalyst particles in the micron range are used. 2 Tellurium-containing solid The tellurium-containing solid present in the reaction zone as part of the catalyst layer includes tellurium alone, tellurium monoxide,
Organic tellurium compounds such as tellurium dioxide, tellurium trioxide, tellurite acid, telluric acid, tellurium methoxide, tellurium ethoxide, etc. can be used as they are, or they can be combined with inert materials such as silica, alumina, silica/alumina, titania, silica/titania, etc. Examples include those supported on a carrier or the tellurium-containing metal oxide itself. The tellurium content in the tellurium-containing solid is 1% by weight
It is preferable that it is above. Tellurium metal, tellurium dioxide, tellurium trioxide,
As tellurite acid, telluric acid, organic tellurium compounds, etc., commercially available reagents or those prepared from various tellurium raw materials by known methods may be used. When using the tellurium component supported on various carriers, various means can be applied as the supporting method. For example, tellurium metal, tellurium dioxide, tellurium trioxide, tellurite acid, telluric acid, tellurium nitrate, basic tellurium nitrate, tellurium halide, tellurium sulfate, organic tellurium compounds, etc. can be used as tellurium raw materials. is mixed with carrier raw materials such as silica sol, alumina sol, titania sol, etc. and then spray-dried, or by impregnating and supporting a previously prepared carrier with a solution containing these raw materials. Furthermore, when a tellurium-containing fluidized catalyst is used for this purpose, any known catalyst manufacturing method can be used. Further, a catalyst prepared by any known method may be used as it is or after being used in the reaction.
It can also be produced by impregnating this with a liquid containing a tellurium component, drying and firing it. In addition to the tellurium component, tellurium-containing solids include alkali metals, alkaline earth metals, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, zinc, boron, aluminum, tin, lead, phosphorus, arsenic, and antimony. , bismuth, sulfur, selenium, etc., but when such tellurium-containing solids are mixed with the target catalyst and reacted according to the method of the present invention, the target product can be selected. It is acceptable as long as it does not negatively affect sexuality. The physical properties of tellurium-containing solids require special attention when used in flow reactions. Preferably, the tellurium-containing solid can be co-fluidized with the catalyst. Therefore, it is desirable that the particle size and particle density be similar to those of the catalyst. The amount of the tellurium-containing solid mixed can be varied depending on the metal oxide catalyst used, the target reaction, and the reaction conditions. If the amount is too small, the effect will be small and it will take time to develop the effect, while if it is too large, negative effects will occur. The most practical and reliable method is to add the tellurium-containing solid little by little and follow the progress of the reaction, and when the desired level is reached, stop adding the tellurium-containing solid, and repeat this process if necessary. be. Once the situation is known to some extent, small amounts of tellurium-containing solids can be continuously fed. The effect may be observed even when the amount of tellurium-containing solid mixed into the catalyst is about 0.01% by weight of the amount of catalyst used. If too much tellurium-containing solid is mixed in,
Generally, it first appears as a decrease in reaction rate. In the case of a decrease in activity due to excessive deposition of tellurium on the catalyst, if it is mild, it can be gradually recovered by stopping the incorporation of the tellurium-containing solid and continuing the reaction. However, if the decrease is large, it may be necessary to partially replace the catalyst, so care must be taken. It is safe to limit the amount of tellurium-containing solids mixed in at a time to a maximum of 30% or less of the amount of catalyst used. Mixing a large amount at once is not necessarily advantageous when considering the extent and sustainability of the effect, and there is also the risk of negative effects due to the above-mentioned excessive amount of mixing. Although there are some differences in the manifestation of the effect depending on the form of tellurium present in the tellurium-containing solid, even if the tellurium-containing solid is mainly composed of tellurium oxides with low vapor pressure in air, the ammoxidation reaction zone If present in
The time required for the effect to appear is several hours at most. 3 Ammoxidation The present invention is carried out while carrying out ammoxidation of an organic compound, and the conditions for the ammoxidation itself are known. The approximate range is as follows. The supply gas molar ratio is hydrocarbons/oxygen/ammonia (molar ratio) 1/0.3-10/0.5-5
If necessary, nitrogen, water vapor, carbon dioxide gas, carbon monoxide, helium, etc. can be added as a diluting gas. The reaction temperature is 300-500%, and the apparent contact time is 0.1-20 seconds. 4 Experimental Examples The yield and selectivity of the target product in this specification are based on the following definitions. Yield [%] = Carbon weight of the target product produced / Carbon weight of the supplied raw material hydrocarbon × 100 Selectivity [%] = Carbon weight of the target product produced / Carbon weight of the reacted raw material hydrocarbon × 100 The activity test conditions are as follows. (1) Ammoxidation reaction of propylene A catalyst is packed into a fluidized bed reactor with an inner diameter of the catalyst fluidizing section of 5 cm and a height of 2 m. A gas having the following composition is fed into this reactor at an apparent linear velocity of 15 cm/sec. The reaction pressure is normal pressure. O ₂ (supplied with air)/propylene = 2.10 (molar ratio) NH ₃ /propylene = 1.15 (molar ratio) However, the connection time is defined as follows. Contact time [sec] = Catalyst packing volume [] ^* /Supplied gas flow rate [/sec] *Catalyst bulk density standard (2) Toluene ammoxidation reaction Same reactor as used for propylene ammoxidation reaction in the previous section and the apparent linear velocity is 15
Feed at cm/sec. The reaction pressure is normal pressure. O ₂ (supplied with air)/toluene = 2.5 (mole ratio) NH ₃ /toluene = 1.5 (mole ratio) Steam/toluene = 2.5 (mole ratio) The definition of contact time is also the same as in the case of ammoxidation of propylene in the previous section. It is. Example 1 Using a fluidized bed catalyst having the empirical formula Fe ₁₀ Sb ₂₅ V _0.1 P _0.5 O _65.4 (SiO ₂ ) ₃₀ , an activity test was conducted under test conditions (1). Acrylonitrile yield was 74.2%. In addition, a tellurium-containing solid containing 16% by weight of Te (the remainder consists of oxygen and silicon) (the same applies in the following examples) is added to the catalyst in an amount of 3.5% by weight.
When the mixture was mixed and the reaction was carried out in such a ratio, the yield of acronitrile was 77.2% after 2 hours. After that, the reaction was carried out for another 2 hours, but
The yield remained unchanged. Example 2 An activity test was conducted under test conditions (1) using a fluidized bed catalyst having the empirical formula W _0.5 Co ₅ Fe ₁₀ Sb ₂₅ O _71.5 (SiO ₂ ) ₃₀ . The yield of acrylonitrile was initially 74.1%, but due to the prolonged use of the reaction, the activity of the catalyst decreased and it became 65.2%. When this was mixed with a tellurium-containing solid containing 32% by weight of Te at a ratio of 1.5% by weight to the catalyst and a reaction was carried out, the acrylonitrile yield was 72.8% after 3 hours. Example 3 Using a fluidized bed catalyst having the empirical formula Sn ₁₀ Sb ₂₅ O ₇₀ (SiO ₂ ) ₃₀ , an activity test was conducted under test conditions (1). Acrylonitrile yield was 68.9%. When this was mixed with a tellurium-containing solid containing 16% by weight of Te at a ratio of 3.5% by weight to the catalyst and a reaction was carried out, the acrylonitrile yield was 73.5% after 2 hours. Example 4 Using a fluidized bed catalyst having the empirical formula U ₁₀ Sd ₃₀ O _86.7 (SiO ₂ ) ₆₀ , an activity test was conducted under test conditions (1). The acrylonitrile yield was initially 69.5%, but the activity of the catalyst decreased due to long-term reaction use.
It became 64.8%. When this was mixed with a tellurium-containing solid containing 32% by weight of Te as a catalyst to give a ratio of 1.5% by weight, a reaction was carried out, and after 2 hours, the yield of acrylonitrile was 70.2%. Example 5 The empirical formula is P _0.5 K _0.1 Fe ₃ Ni _2.5 Co _4.5 Bi ₁ Mo ₁₂ O _50.3
(SiO ₂ ) Using a fluidized bed catalyst of ₄₅ , test conditions (1)
An activity test was conducted using The acrylonitrile yield was initially 75.3%, but due to the long-term use of the reaction, the activity of the catalyst decreased and it became 71.8%. To this, a tellurium-containing solid containing 16% by weight of Te,
When the reaction was carried out by mixing at a ratio of 0.5% by weight to the catalyst, the acrylonitrile yield was 73.8% after 1.5 hours and 74.2% after 5 hours. Example 6 An activity test was conducted under test conditions (2) using a fluidized catalyst whose empirical formula was P ₁ V ₁₂ O _32.5 (SiO ₂ ) ₅₀ . The benzonitrile yield was 75.2%. When this was mixed with a tellurium-containing solid containing 16% by weight of Te as a catalyst to give a ratio of 0.5% by weight, the benzonitrile yield was 76.3% after 2 hours. 【table】

Claims (1)

[Claims] 1. A method for ammoxidizing an organic compound using a catalyst at a temperature of 300°C to 500°C, in which the ammoxidation is carried out using a metal oxide catalyst that does not substantially contain tellurium and a tellurium-containing solid. An ammoxidation method characterized in that it is carried out in the presence of a mixture of. 2. The method according to claim 1, wherein the metal oxide catalyst contains at least one element selected from the group consisting of antimony, molybdenum, and vanadium. 3. Claim 1, wherein the metal oxide catalyst is a fluidized catalyst with a particle size in the range of 5 to 200 microns.
The method according to any one of Items 1 to 2. 4 Tellurium-containing solids react with metal oxide catalysts
4. A method according to any one of claims 1 to 3, wherein the compound is present in a proportion of 0.01% by weight or more. 5. The method according to any one of claims 1 to 4, wherein the tellurium content of the tellurium-containing solid is 1% by weight or more. 6. The method according to any one of claims 1 to 5, wherein the tellurium-containing solid is simple tellurium, tellurium oxide, tellurium oxide hydrate, or an organic tellurium compound. 7. Any one of claims 1 to 5, wherein the tellurium-containing solid is one in which tellurium alone, tellurium oxide, tellurium oxide hydrate, or an organic tellurium compound is supported on an inert carrier. The method described in. 8 The inert carrier is silica, alumina, silica, etc.
The method according to claim 7, wherein at least one member is selected from the group consisting of alumina, titania, silica-titania, and zirconia. 9 The tellurium-containing solid is tellurium and an alkali metal,
Alkaline earth metals, chromium, molybdenum, tungsten, vanadium, manganese, iron, cobalt,
Nickel, copper, zinc, boron, aluminum,
A patent claim that is a compound or compound mixture containing at least one element selected from the group consisting of tin, lead, phosphorus, arsenic, antimony, bismuth, sulfur, and selenium, and/or a compound supported on an inert carrier. The method according to any one of items 1 to 8.