KR101523110B1 - Process for the ammoxidation of propane and isobutane using mixed metal oxide catalysts - Google Patents

Abstract

The present invention relates to a process for the ammonia oxidation of saturated or unsaturated hydrocarbons or mixtures of saturated and unsaturated hydrocarbons for the production of unsaturated nitriles wherein the process is carried out in the presence of at least one of molybdenum, vanadium, antimony, niobium, tellurium, optionally titanium, tin, germanium, Hafnium and at least one lanthanum selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, Comprising contacting a mixture of saturated or unsaturated hydrocarbons or saturated and unsaturated hydrocarbons with ammonia and an oxygen-containing gas, in the presence of a catalyst composition comprising a Group III-V catalyst. The catalyst is characterized by a very low level of tellurium in the composition. The catalyst composition is effective for gas phase conversion (via ammonia oxidation) of propane to acrylonitrile and of isobutane to methacrylonitrile.

Description

TECHNICAL FIELD The present invention relates to a method for ammonia oxidation of propane and isobutane using a mixed metal oxide catalyst,

The present invention generally relates to a process for the preparation of unsaturated nitriles or unsaturated organic acids, which process comprises the step of adding ammonia or a method of oxidation of saturated or unsaturated hydrocarbons.

The present invention relates in particular to a process for the conversion of propane to acrylonitrile and to the conversion of isobutane to methacrylonitrile in a gaseous phase (via ammonia oxidation) or propane to acrylic acid and to isobutane methacrylate Gas phase conversion (via oxidation).

Mixed metal oxide catalysts are applied to the conversion of propane to acrylonitrile and the conversion of isobutane to methacrylonitrile (via an ammonia oxidation reaction) and / or propane to acrylic acid (via an oxidation reaction). US Patent No. 6,036,880 to Komada et al., U.S. Patent No. 6,043,186 to Komada et al., U.S. Patent No. 6,143,916 to Hinago et al., U.S. Pat. No. 6,143,916 to Inoue et al. U.S. Patent Application No. 2003/0088118 A1 to Komada et al., U.S. Patent Application No. 2004/0063990 A1 to Gaffhey et al., And PCT Patent Application No. PCT / US99 / 099647 by Asahi Kasei Kabushiki Kaisha. Including many patents and patent applications, including WO 2004/108278 A1.

Conversion of propane to acrylonitrile and of isobutane to methacrylonitrile (via ammonia oxidation) and / or propane to acrylic acid, and of isobutane to methacrylic acid (via oxidation) Despite advances in the art relating to catalysts containing molybdenum, vanadium, antimony and niobium that are effective for conversion, the catalysts require further improvement before they are commercially available. In general, catalyst systems known in the art for such reactions generally suffer from difficulties due to the low yield of the desired product.

Tellurium can become volatile at the temperatures used for the ammonia oxidation of propane and isobutane and / or the conversion of propane to acrylic acid, and the conversion of isobutane to methacrylic acid (via an oxidation reaction). Catalysts containing a relatively high amount of tellurium exhibit loss of tellurium during ammonia oxidation or oxidation operations. Catalytic performance can be negatively affected by the loss of tellurium.

Summary of the Invention

In one embodiment, the present invention relates to a process for the ammonia oxidation of a saturated or unsaturated hydrocarbon, or a mixture of saturated and unsaturated hydrocarbons, for preparing an unsaturated nitrile, said process comprising the steps of: Wherein at least one element selected from the group consisting of titanium, tin, germanium, zirconium and hafnium and optionally at least one element selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, Comprising contacting a mixture of saturated or unsaturated hydrocarbons or saturated and unsaturated hydrocarbons with ammonia and an oxygen-containing gas in the presence of a catalyst composition comprising at least one lanthanide selected from the group consisting of: The catalyst composition used in the process is further characterized by a relatively low level of tellurium in the composition.

In one embodiment, the present invention is a method of converting a hydrocarbon selected from the group consisting of propane, isobutane, or mixtures thereof to acrylonitrile, methacrylonitrile, or mixtures thereof, wherein the process comprises reacting molybdenum, vanadium, antimony, At least one element selected from the group consisting of niobium, tellurium, optionally titanium, tin, germanium, zirconium and hafnium, and optionally at least one element selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, Containing gas and ammonia in the vapor phase, elevated temperature, in the presence of a catalytic composition comprising at least one lanthanide selected from the group consisting of barium and lutetium.

In another aspect, the present invention is also directed to a process for the preparation of a catalyst for the catalytic combustion of at least one element selected from the group consisting of molybdenum, vanadium, antimony, niobium, tellurium, optionally titanium, tin, germanium, zirconium, and hafnium, and optionally lanthanum, cerium, praseodymium, neodymium , At least one lanthanide selected from the group consisting of samarium, europium, gadolinium, dysprosium, holmium, erbium, tulirite, etherbium, and lutetium.

In one embodiment, the catalyst composition comprises a mixed oxide of the following formula:

Mo _l V _a Sb _b Nb _c Te _d X _e L _f o _n

Wherein X is selected from the group consisting of Ti, Sn, Ge, Zr, Hf, and mixtures thereof,

L is selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,

0.1 < a < 0.8,

0.01 < b < 0.6,

0.001 < c < 0.3,

0.001 < d < 0.06,

0 < e &lt; 0.6,

0 < f &lt;0.1;

n is the number of oxygen atoms necessary to meet the valence requirement of all other elements present in the mixed oxide, provided that at least one other element of the mixed oxide may be in a lower oxidation state than its highest oxidation state And a, b, c, d, e and f represent molar ratios of the corresponding elements to 1 mol of Mo).

In another embodiment, X is Ti, Sn or a mixture thereof.

In another embodiment, L is Nd, Ce, or Pr.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally relates to a process for the oxidation of (saturated ammonia) of saturated or unsaturated hydrocarbons, and to catalyst compositions which can be used in the process. The process can be used to convert ammonia of propane to acrylonitrile and of isobutane into methacrylonitrile and / or conversion of propane to acrylic acid and of isobutane to methacrylic acid (via an oxidation reaction) .

Catalyst composition

In one embodiment, the catalyst composition applied in the process of the present invention comprises at least one element selected from the group consisting of molybdenum, vanadium, antimony, niobium, tellurium, optionally titanium, tin, germanium, zirconium, and hafnium, At least one lanthanide selected from the group consisting of cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, tulirite, etherbium and lutetium. The catalyst composition used in the process is further characterized by a relatively low level of tellurium in the composition, and in one embodiment, the molar ratio of molybdenum to tellurium (Mo: Te) is from 1: 0.001 to 1: 0.06. In another embodiment, the molar ratio of molybdenum to tellurium (Mo: Te) is 1: 0.001 to 1: 0.05. As used herein, " one or more lanthanides selected from the group consisting " of one or more elements selected from the group consisting "of" Or mixtures of lanthanides.

In one embodiment, the catalyst composition comprises a mixed oxide of the following formula:

Mo _l V _a Sb _b Nb _c Te _d X _e L _f o _n

Wherein X is selected from the group consisting of Ti, Sn, Ge, Zr, Hf, and mixtures thereof;

L is selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and mixtures thereof;

0.1 < a < 0.8,

0.01 < b < 0.6,

0.001 < c < 0.3,

0.001 < d < 0.06,

0 < e &lt; 0.6,

0 < f &lt;0.1;

n is the number of oxygen atoms necessary to meet the valence requirements of all other elements present in the mixed oxide, provided that at least one other element of the mixed oxide may be in a lower oxidation state than its highest oxidation state, b, c, d, e and f represent the molar ratio of the corresponding element to 1 mol of Mo).

In one embodiment, the catalyst composition comprises a mixed oxide of the following formula:

Mo _l V _a Sb _b Nb _c Te _d X _e L _f o _n

Wherein X is selected from the group consisting of Ti, Sn, and mixtures thereof;

L is selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and mixtures thereof;

0.1 < a < 0.8,

0.01 < b < 0.6,

0.001 < c < 0.3,

0.001 < d < 0.06,

0 < e &lt; 0.6,

0 < f &lt;0.1;

n is the number of oxygen atoms necessary to meet the valence requirements of all other elements present in the mixed oxide, provided that at least one other element of the mixed oxide may be in a lower oxidation state than its highest oxidation state, b, c, d, e and f represent the molar ratio of the corresponding element to 1 mol of Mo).

In another embodiment of the catalyst composition described by the above formula, X is one of Ti or Sn. In another embodiment of the catalyst composition described by the above formula, X is Ti, X is Sn, X is Ge, X is Zr, and X is Hf.

In another embodiment of the catalyst composition described by the above formula, L is one of Nd, Ce, or Pr. In another embodiment, L is either Nd or Pr. In another embodiment of the catalyst composition described by the above formula, L is La, L is Ce, L is Pr, L is Nd, L is Sm, L is Eu, L is Gd and L Is Tb, L is Dy, L is Ho, L is Er, L is Tm, L is Yb, and L is Lu.

In another embodiment of the catalyst composition described by the above formula, the catalyst composition does not contain tantalum.

A, b, c, d, e, and f are each independently in the following ranges: 0.1 <a, 0.2 <a, a <0.4, a <0.8 C, 0.01 <c, 0.03 <c, 0.04 <c, c <0.1, c <0.12, c <0.01, 0.01 <b, 0.1 <b, b <0.3, b <0.4, b <0.6, 0.001 < D < 0.025, d < 0.03, d < 0.03, d < 0.04, d < 0.04, d < 0.05 e, e <0.05, e <0.1, e <0.15, e <0.2, e <0.3, e <0.6 and 0 0.001 <f, 0.003 <f, and 0.004 <f, f <0.006, f <0.01, f <0.015, f <0.02, f <0.05, f <0.1.

In one embodiment of the catalyst composition described by the above formula, the catalyst may further contain lithium and optionally contain one or more other alkali metals. In this embodiment, the catalyst composition comprises a mixed oxide of the formula:

Mo _l V _a Sb _b Nb _c Te _d X _e L _{f g} Li _h O _n

Wherein A is at least one of Na, K, Cs, Rb and a mixture thereof, and 0 < g &gt;, wherein X, L, a, b, c, d, &Lt; 0.1, 0 &lt; h &lt; 0.1, and 'g' and 'h' represent the molar ratio of the corresponding element to Mo 1 mole). In another embodiment of the catalyst composition comprising the mixed oxide described by the above formula, the catalyst composition does not contain Na, K, Cs, Rb or a mixture thereof (i.e., g is equal to 0). In another embodiment of the catalyst composition comprising the mixed oxide described by the above formula, 0 <h, 0.03 <h, h <0.06, h <0.1.

The catalyst of the present invention may be supported or unsupported (i.e., the catalyst may comprise a support, or it may be a bulk catalyst). Suitable supports are silica, alumina, zirconia, titania, or mixtures thereof. However, zirconia or titania can be used as support material so that the ratio of molybdenum to zirconium or titanium increases above the value shown in the above formula, and the Mo to Zr or Ti ratio is about 1: 1 to 1:10. The support typically serves as a binder to produce a catalyst that is both harder and more friction resistant. However, for commercial applications, proper mixing of both the active phase (i. E. The complexes of the catalyst oxides described above) and the support is useful to obtain acceptable activity and hardness (friction resistance) for the catalyst. Directly, an increase in the amount of the active phase reduces the hardness of the catalyst. The support comprises from 10 to 90% by weight of the supported catalyst. Typically, the support comprises from 40 to 60% by weight of the supported catalyst. In one embodiment of the present invention, the support may comprise up to about 10% by weight of the supported catalyst. In one embodiment of the invention, the support may comprise up to about 30% by weight. In yet another embodiment of the present invention, the support may comprise about 70% by weight. It is possible that the support material may contain one or more promoter elements such as, for example, silica sol containing sodium (Na), and such promoter elements may be incorporated into the catalyst through the support material. In one embodiment, the support comprises low-sodium silica.

Catalyst preparation

Catalysts useful in the present invention may be prepared by a variety of methods. Two possible synthetic methods are described herein. The first synthesis method is performed at approximately atmospheric pressure (hereinafter referred to as non-hydrothermal method or synthesis), while the second synthesis method is typically performed under elevated pressure in an autoclave (hereinafter referred to as hydrothermal method or synthesis) . Non-hydrothermal synthesis methods are described in US 6,514,902, US 7,087,551, US, 109,144, WO 2004/108278 and WO 2006/019078, which are incorporated herein by reference.

In one embodiment, the catalysts of the present invention can be prepared by non-hydrothermal synthesis as follows: ammonium heptamolybdate, ammonium metavanadate and diantimony trioxide are added to water, and then the resulting mixture is heated to 50 Lt; 0 &gt; C or more to obtain an aqueous mixture (A). In one embodiment, the heating is carried out while stirring the mixture. Advantageously, the aqueous mixture is heated to a temperature within the range of 70 占 폚 to the normal boiling point of the mixture. Heating is carried out under reflux using equipment with a reflux condenser. For reflux heating, the boiling point is generally in the range of about 101 ° C to 102 ° C. The temperature rise is maintained for 0.5 hours or more. When the heating temperature is low (for example, less than 50 占 폚), the heating time needs to be long. When the heating temperature is in the range of 80 占 폚 to 100 占 폚, the heating time is typically in the range of 1 hour to 5 hours.

Briefly, after heating, silica sol and hydrogen peroxide are added to the aqueous mixture (A). When the hydrogen peroxide is added to the aqueous mixture (A), the hydrogen peroxide has a molar ratio of hydrogen peroxide to antimony (H ₂ O ₂ / Sb molar ratio) compound in the range of 0.01 to 20, 0.5 to 3, 2.5. &Lt; / RTI &gt; In the case of the hydrogen peroxide addition, the aqueous mixture (A) is stirred at a temperature in the range of 30 DEG C to 70 DEG C for 30 minutes to 2 hours.

An aqueous liquid (B) is obtained by adding a niobium compound (e.g., niobic acid) to water, and then heating the resulting mixture to a temperature in the range of 50 캜 to nearly 100 캜. Advantageously, the aqueous liquid (B) contains a niobium compound in addition to the dicarboxylic acid (for example oxalic acid). In general, the molar ratio of dicarboxylic acid to niobium compound with respect to niobium is in the range of 1 to 4, advantageously in the range of 2 to 4. That is, in this case, niobic acid and oxalic acid are added to water, and then the resulting mixture is heated and stirred to obtain an aqueous liquid (B).

A useful method of making the aforementioned aqueous liquid (B) comprises the following steps: (1) mixing water, dicarboxylic acid (e.g. oxalic acid) and a niobium compound (such as niobic acid) Obtaining a preliminary niobium-containing aqueous solution or a niobium-containing aqueous mixture in which a part of the compound is suspended; (2) cooling the preliminary niobium-containing aqueous solution or the niobium-containing aqueous mixture to precipitate a part of the dicarboxylic acid; And (3) removing the precipitated dicarboxylic acid from the preliminary niobium-containing aqueous solution, or removing the precipitated dicarboxylic acid and the suspended niobium compound from the niobium-containing aqueous mixture to form a niobium- Lt; / RTI &gt; The aqueous liquid (B) obtained in this process usually has a dicarboxylic acid / niobium molar ratio in the range of about 2 to 4.

Particularly useful dicarboxylic acids are oxalic acid, and the niobium compounds useful in step (1) of the process include niobic acid, niobium hydrogen oxalate and ammonium niobium oxalate. These niobium compounds can be used in solid form, as a mixture, or as a suspension in a suitable medium. When niobium hydrogen oxalate or ammonium niobium oxalate is used as the niobium compound, the dicarboxylic acid can not be used. When niobic acid is used as the niobium compound, the niobic acid may be washed with aqueous ammonia and / or water prior to use to remove acidic impurities that may be precipitated during the preparation thereof. In one embodiment, freshly prepared niobium compounds may be used as niobium compounds. However, in the above-mentioned method, the niobium compound can be used (for example, by decomposition) by being slightly modified as a result of long-term storage or the like. In step (1) of the process, the dissolution of the niobium compound may be promoted by the addition or heating of a small amount of aqueous ammonia.

The concentration of the niobium compound (with respect to niobium) in the preliminary niobium-containing aqueous solution or aqueous mixture can be maintained within the range of 0.2 to 0.8 moles per kg of solution or mixture. In one embodiment, the dicarboxylic acid may be used in an amount such that, with respect to niobium, the mole ratio of the dicarboxylic acid to the niobium compound is approximately 3 to 6. Where an excess of dicarboxylic acid is used, a large amount of niobium compound may be dissolved in the aqueous solution of dicarboxylic acid; The cooling of the obtained preliminary niobium-containing aqueous solution or mixture leads to an excessively large amount of dicarboxylic acid to be precipitated, resulting in a disadvantage that the use of the dicarboxylic acid is reduced. On the other hand, when an insufficient amount of dicarboxylic acid is used, a large amount of niobium compound remains unmelted and suspended in an aqueous solution of dicarboxylic acid to form a mixture in which the suspended niobium compound is removed from the aqueous mixture, There is a disadvantage that the degree of use of the compound is decreased.

A suitable cooling method can be used in step (2). For example, cooling can be simply performed using an ice bath.

The removal of the precipitated dicarboxylic acid (or the precipitated dicarboxylic acid and the dispersed niobium compound) of step (3) can be easily carried out by a conventional method, for example, slope separation or filtration.

The dicarboxylic acid / niobium molar ratio of the obtained niobium-containing aqueous solution is outside the range of about 2 to 4, and the niobium compound or dicarboxylic acid is an aqueous liquid such that the dicarboxylic acid / niobium molar ratio of the solution falls within the above- (B). In general, however, the above operation is unnecessary because the aqueous liquid (B) having a dicarboxylic acid / niobium molar ratio within the range of 2 to 4 contains the concentration of the niobium compound, the molar ratio of the dicarboxylic acid to the niobium compound, And can be prepared by appropriately adjusting the cooling temperature of the above-mentioned preliminary niobium-containing aqueous solution or aqueous mixture.

The aqueous liquid (B) may also be prepared to further contain component (s). For example, at least a portion of an aqueous liquid (B) containing a niobium compound or containing a mixture of a niobium compound and a dicarboxylic acid is used with hydrogen peroxide. In this case, it is advantageous to provide the amount of hydrogen peroxide such that the molar ratio of hydrogen peroxide to niobium compound (H ₂ O ₂ / Nb molar ratio) is in the range of 0.5 to 20, 1 to 20 with respect to niobium.

In yet another embodiment, some or more of the aqueous liquid (B) containing a niobium compound or containing a mixture of a niobium compound and a dicarboxylic acid or a mixture thereof with a hydrogen peroxide may further comprise an antimony compound Trioxide), titanium compounds (such as titanium dioxide, which may be a mixture of rutile and rutile form) and / or cerium compounds (such as cerium acetate). In this case, the amount of the hydrogen peroxide is such that the molar ratio of the hydrogen peroxide to the niobium compound (H ₂ O ₂ / Nb molar ratio) is 0.5 to 20, 1 to 20 with respect to niobium. In yet another embodiment, at least a portion of the aqueous liquid (B) and the antimony compound mixture of hydrogen peroxide are selected such that the molar ratio (Sb / Nb molar ratio) of antimony compound to niobium compound relative to antimony is less than or equal to 5, Range.

The aqueous mixture (A) and the aqueous liquid (B) are mixed together in suitable proportions according to the desired composition of the catalyst, typically providing an aqueous mixture of the components in the form of a slurry. The content of components in the aqueous mixture is generally in the range of about 50% by weight, 70 to 95% by weight, and 75 to 90% by weight.

For the preparation of the silica carrier-supported catalyst of the present invention, the aqueous feedstock mixture is prepared to contain a silica source (i. E., Silica sol or fumed silica). The amount of silica source can be suitably adjusted according to the amount of silica carrier in the obtained catalyst.

Drying step

The aqueous mixture of components is dried to provide a dry catalyst precursor. The drying can be carried out by conventional methods such as spray drying or evaporative drying. Spray drying is particularly useful because fine, spherical, dry catalyst precursors are obtained. Spray drying can be performed by centrifugation, a two-phase flow nozzle method, or a high-pressure nozzle method. As a heat source for drying, air that has been heated by steam, an electric heater or the like in the embodiment is used. There is an embodiment in which the temperature of the spray dryer at the inlet of the drying compartment is 150 ° C to 300 ° C.

Firing step

The dry catalyst precursor is converted to a mixed metal oxide catalyst by calcination. Firing can be carried out using rotary kilns, fluid bed kills, fluidized bed reactors, fixed bed reactors, and the like. The calcination conditions are selected such that the specific surface area of the catalyst to be formed is about 5 m ² / g to 35 m ² / g, and about 15 m ² / g to about 20 m ² / g. Firing includes heating the dry catalyst precursor to a final temperature in the range of about 600 to 680 &lt; 0 &gt; C.

In the present invention, the calcination process comprises heating the dry catalyst precursor continuously or intermittently at a pre-calcination temperature of greater than 200 DEG C to less than about 400 DEG C, less than about 350 DEG C, less than about 300 DEG C at a rate greater than 15 DEG C / . In one embodiment, the prefiring temperature is 300 占 폚. In one embodiment, the heating rate is about 20 ° C / min. In another embodiment, the heating rate is about 25 ° C / min. In another embodiment, the heating rate is about 30 DEG C / min. In yet another embodiment, the dry catalyst precursor is introduced into a heated calciner maintained at a temperature of about 300 ° C or slightly higher, so that the temperature of the precursor is quickly increased to about 300 ° C.

 The heating rate of the pre-firing temperature to the final temperature is about 0.5 占 폚 / min, 1 占 폚 / min, 2 占 폚 / min, 5 占 폚 / min, or 0.5 to 5 占 폚 / min. In one embodiment, the heating rate from about 300 캜 to the intermediate temperature is about 1 캜 / minute, and the heating rate is from 15 캜 / min to 20 캜 / min, 25 캜 / , Or &lt; RTI ID = 0.0 &gt; 30 C / min. In another embodiment, the solid is cooled after obtaining the intermediate temperature and then cooled to a final temperature at a heating rate of greater than about 15 ° C / minute, greater than 20 ° C / minute, greater than 25 ° C / minute, or greater than 30 ° C / Can be heated.

In one embodiment of the present invention, firing is carried out in two firing stages: (1) below the intermediate or prebaking temperature, and (2) between the intermediate or prefiring to the final temperature. In one embodiment, optionally calcined solid (1) fired solids can be introduced into a heated calciner maintained at the same temperature as the final final temperature to rapidly increase the precursor temperature to the final temperature.

In one embodiment, the heating rate for a temperature range of from about 300 ° C to about 340 ° C to 350 ° C, 345 ° C is about 0.5 ° C / min or 1 ° C / min, or about 2 ° C / RTI ID = 0.0 &gt; 5 C / min. &Lt; / RTI &gt; In one embodiment, the solids are maintained at a temperature in the range of 300 to 400 占 폚, 340 to 350 占 폚, and 345 占 폚 for about 1 to 4 hours. In one embodiment, the solids are heated at a rate of 2.45 ° C / min in a temperature range of 345-680 ° C.

When achieving the final temperature, the solids can be maintained at this temperature for about 1 to about 3 hours, for about 2 hours. The final temperature may be any temperature within the range of 600 ° C, 610 ° C, 620 ° C, 630 ° C, 640 ° C, 650 ° C, 660 ° C, 670 ° C, and 680 ° C, or 600 to 680 ° C. In one embodiment, the solids are heated at a rate of about 0.5O &lt; 0 &gt; C / min to about 6O0C to about 680 &lt; 0 &gt; C. In one embodiment, the solids are heated at a rate of 1 deg. C / min from about 600 deg. C to about 680 deg.

The firing can be carried out in air or under air flow. However, some of the firing is carried out under an atmosphere of a gas such as a nitrogen gas which is substantially free of oxygen (for example, under the flow of gas). The present invention includes the use of an inert gas. The inert gas may comprise fresh gas. The gas may include nitrogen. The gas may include a choice from air, steam, superheated steam, carbon monoxide, and carbon dioxide. In one embodiment of the present invention, firing is performed under a flow of substantially oxygen free nitrogen gas (1) in a temperature range of from about 400 to 450 DEG C and (2) in a temperature range of greater than about 400 to 450 DEG C . In another embodiment of the present invention, the calcination is carried out in the presence of (1) a flow of air for a temperature range of 400-450 DEG C and below, and (2) a substantially oxygen free nitrogen Can be carried out under a gas flow. The flow rate of the gas may (1) be particularly important for a temperature range of about 400-450 ° C. The flow rate of the gas may range from about 0.67 to about 2.5 sccm per gram of catalyst precursor per minute.

In one embodiment, the catalyst precursor is calcined under nitrogen in a two-foot vertical tube in two stages. The temperature of the loaded one foot vertical tube is raised to 345 DEG C at a rate of about 1.2 DEG C / min and then the temperature is maintained at 345 DEG C for 4 hours. In step 2, the temperature was raised to a temperature of 640 DEG C at a further rate of about 2.3 DEG C / min. After dwelling at 640 캜 for 2 hours, firing is completed.

Incorporation of tellurium

Tellurium can be incorporated into the catalyst by adding the tellurium source mixture to either the aqueous mixture (A), the aqueous mixture (B), or the mixture of the aqueous mixture (A) and the aqueous mixture (B). In one embodiment, tellurium can be added to the catalyst by impregnation. In one embodiment, the impregnation is carried out by contacting the calcination catalyst produced by the process as described in the present application with a solution of Te (OH) ₆ and water. The solution is added to the catalyst while stirring, until the catalyst reaches a point of incipient wetness to produce a catalyst having the desired level of tellurium per mol of molybdenum on the catalyst surface. The catalyst is then dried, typically by allowing the catalyst to stand overnight in a 90 ° C oven and drying in air. The dried impregnated material is typically heat treated under nitrogen at 450 占 폚 for 2 hours.

Heat number  Synthesis method

In one embodiment, the catalyst compositions described herein can be prepared by hydrothermal synthesis methods. The hydrothermal synthesis method is described in U.S. Patent Application No. 2003/0004379 to Gaffhey et al., [Watanabe et al., "New Synthesis Route for Mo-V-Nb-Te mixed oxides catalyst for propane ammoxidation", Applied Catalysis A : General, 194-195, pp. Applied Catalysis A: General, 200, pp. 479-485 (2000) and Ueda et al., "Selective Oxidation of Light Alkanes over Hydrothermally Synthesized Mo-VMO (M = Al, Ga, Bi, Sb and Te) . 135-145.

Generally, the catalyst compositions described herein can be prepared by hydrothermal synthesis, wherein the source compound (i. E., The compound containing and / or providing one or more metals with respect to the mixed metal oxide catalyst composition) is mixed in an aqueous solution To form a reaction medium, and the reaction medium is reacted for a sufficient time in a sealed reaction vessel at an elevated temperature and a raised pressure to form a mixed metal oxide. In one embodiment, the hydrothermal synthesis is carried out by reacting any organic compound present in the reaction medium, such as a solvent used in the preparation of the catalyst or any organic compound being added, with any of the source compounds that provide the mixed metal oxide of the catalyst composition For a sufficient period of time. This embodiment simplifies the further handling and processing of the mixed metal oxide catalyst.

The source compound is reacted in a sealed reaction vessel at a temperature above 100 &lt; 0 &gt; C and a pressure above ambient pressure to form a mixed metal oxide precursor. In one embodiment, the source compound reacts in a sealed reaction vessel at a temperature of at least about 125 캜, in another embodiment at a temperature of at least about 150 캜, and in yet another embodiment at a temperature of at least about 175 캜. In one embodiment, the source compound reacts in a sealed reaction vessel at a pressure of at least about 25 psig, and in another embodiment at least about 50 psig, and in yet another embodiment, at least about 100 psig. The sealed reaction vessel is equipped with a pressure regulating device so as to avoid over pressurizing the vessel and / or to regulate the reaction pressure.

In one or more embodiments, the source compound is reacted by a protocol that involves mixing the source compound during the reaction step. The particular mixing mechanism is not critical and may include mixing (e.g., stirring or shaking) the ingredients during the reaction by any effective method. The method includes, for example, shaking the contents of the reaction vessel by shaking, tumbling or vibrating the component-containing reaction vessel. The method also provides relative force between the agitating member and the reaction vessel, including, for example, agitating members that are at least partially located within the reaction vessel, and agitation using the driving force attached to the agitating element or reaction vessel . The stirring member may be a shaft-driven and / or a shaft-supported stirring member. The driving force may be directly coupled to the agitating member or indirectly (e. G., Via magnetic coupling) to the agitating member. Mixing is generally sufficient to mix the components, allowing an efficient reaction between components of the reaction medium, resulting in a more homogeneous reaction medium (e. G., Producing a more homogenous mixed metal precursor) relative to the unmixed reaction Respectively. This results in more efficient consumption of starting materials and more consistent mixed metal oxide products. Mixing the reaction medium during the reaction step also causes the mixed metal oxide product to form in solution rather than on the reaction vessel surface. This allows for faster recovery and separation of the mixed metal oxide product by techniques such as centrifugation, decanting, or filtration, and eliminates the need to recover multiple products from the reactor vessel surface. More advantageously, having a mixed metal oxide form in solution causes particle growth to occur on all sides of the particle, rather than a limited exposure, if growth occurs from the reactor wall.

It is generally desirable to keep some of the space portion in the reactor vessel. The amount of space portion may vary depending on the type of agitation or container design, if the reaction mixture is agitated. The overhead agitated reaction vessel may, for example, occupy 50% of the space portion. Typically, the space portion is filled with an ambient temperature that provides a certain amount of oxygen to the reaction. However, as is known in the art, the space portion can be filled with other gases to provide a reactant, such as O ₂ or even an inert atmosphere such as Ar or N ₂ . The amount of space and the amount of gas therein is dependent on the desired reaction as is known in the art.

The source compound may react in the sealed reaction vessel at an initial pH of about 4 or less. Through the case of hydrothermal synthesis, the pH of the reaction mixture can be varied so that the final pH of the reaction mixture may be higher or lower than the initial pH. In one or more embodiments, the source compound reacts in a sealed reaction vessel at a pH of about 3.5 or less. In some embodiments, the components are reacted in a sealed reaction vessel at a pH of no greater than about 3.0, no greater than about 2.5, no greater than about 2.0, no greater than about 1.5, or no greater than about 1.0, no greater than about 0.5, In one or more embodiments, the pH ranges from about 0 to about 4, and in other embodiments from about 0.5 to about 3.5. In some embodiments, the pH may range from about 0.7 to about 3.3, or from about 1 to about 3. The pH can be adjusted by adding an acid or base to the reaction mixture.

The source compound may be run for a time sufficient to form the mixed metal oxide in the sealed reaction vessel at the above described reaction conditions (including, for example, reaction temperature, reaction pressure, pH, stirring, etc., as described above) . In one or more embodiments, the mixed metal oxide comprises a solid phase solution comprising the desired elements as discussed above, and in some embodiments some or more of the active and selective propane or isobutane oxidation and / Or &lt; / RTI &gt; contains an essential crystalline structure for the ammonia oxidation catalyst. The exact time is not critical and can range, for example, from about 12 hours to about 18 hours, from about 24 hours to about 30 hours, from about 36 hours to about 42 hours, from about 48 hours to about 54 hours About 60 hours or more, about 66 hours or more, or about 72 hours or more. The reaction time may be more than 3 days, including, for example, about 4 days or more, about 5 days or more, about 6 days or more, about 7 days or more, about 2 weeks or about 3 weeks or about 1 month or more .

After the reaction step, the further step of the catalyst preparation process may comprise a subsequent step, which may include, for example, cooling (e.g., to about ambient temperature) the reaction medium comprising the mixed metal oxide, (E.g., by centrifugation and / or decantation of the supernatant, or alternatively by filtration), washing of the separated solid particles (e. G., Distilled water or deionized water ), Repeating the separation step and the cleaning step one or more times, and performing the final separation step. In one embodiment, the subsequent steps include drying the reaction medium, such as rotary evaporation, spray drying, freeze drying, and the like. This removes the formation of metal containing consuming steam.

After the subsequent step, the washed and separated mixed metal oxides can be dried. Drying of the mixed metal oxide may be carried out under ambient conditions (e.g., at a temperature of about 25 DEG C, at ambient pressure), and / or in an oven. In one or more embodiments, the mixed metal oxide may be dried at a temperature ranging from 40 DEG C to 150 DEG C, and in one embodiment may be dried at a temperature of about 120 DEG C, and during a drying period of from about 5 to about 15 hours Over one hour, and in one embodiment over about 12 hours. The drying can be carried out under controlled or unadjusted pressure, and the drying pressure can be an inert gas, oxidizing gas, reducing gas or air. In one or more embodiments, the drying atmosphere comprises air.

As a further separation step, the dried mixed metal oxide may be treated to form a mixed metal oxide catalyst. The treatment may include, for example, calcination (e.g., including heat treatment under oxidizing or reducing conditions) performed under various treatment atmospheres. Subsequent mixed metal oxides can be decomposed or comminuted intermittently prior to and / or during the pretreatment. In one or more embodiments, the dried mixed metal oxide may optionally be decomposed and then calcined to form a mixed metal oxide catalyst. The firing can be carried out in an inert atmosphere such as nitrogen. In one or more embodiments, the firing conditions include a temperature in the range of about 400 ° C to about 700 ° C, in some embodiments in the range of about 500 ° C to about 650 ° C, and in some embodiments, firing is performed at about 600 ° C .

The treated (e. G., Calcined) mixed metal oxide may be mechanically further processed, for example, by pulverizing, sieving, and processing the mixed metal oxide into a final form for use in a fixed bed or fluid bed reactor. As is known in the art, milling can be accomplished using a variety of methods including jar milling, bead beating, and the like. The optimum milling conditions can be selected according to the sample size and the catalyst composition. In one embodiment, about 2 grams of the unsupported catalyst can be milled in a bead beater for about 2 to about 15 minutes.

In one or more embodiments, the catalyst may be molded into its final form prior to any firing or other heat treatment. For example, in the preparation of a fixed bed catalyst, the catalyst precursor slurry is typically dried by heating at elevated temperatures and then molded (e.g., extruded, pelletized, etc.) prior to calcination in the desired fixed bed catalyst size and configuration. Similarly, in the preparation of a fixed bed catalyst, the catalyst precursor slurry may be spray dried to obtain a microspheroidal catalyst having a particle diameter in the range of 10 to 200 microns and then calcined.

For the catalyst preparation process described herein, a source compound (also referred to herein as a "source" or "sources") containing and providing the metal components used in the various catalyst synthesis methods is provided in a reaction vessel as a metal salt aqueous solution . Some source compounds of the metal component may be provided in the reaction vessel as a solid or slurry comprising solid particles dispersed in an aqueous medium. Some source compounds of the metal component may be provided in the reaction vessel as a slurry or solid comprising solid particles dispersed in a non-aqueous solvent or other non-aqueous medium.

Suitable source compounds for catalyst synthesis as described herein include the following. Suitable molybdenum sources may include molybdenum (VI) oxide (MoO _3), ammonium heptamolybdate or molybdenum acid. Suitable sources of vanadium may include vanadyl sulfate, ammonium metavanadate, or vanadium (V) oxide. Suitable antimony sources may include antimony (III) oxide, antimony (III) acetate, antimony (III) oxalate, antimony (V) oxide, antimony (III) sulfate, or antimony (III) tartrate. Suitable niobium sources may include niobium oxalate, ammonium niobium oxalate, niobium oxide, niobium ethoxide, or niobic acid.

Suitable tellurium sources may include telluric acid, tellurium dioxide, tellurium trioxide, or organic tellurium compounds such as methyl telluride and dimethyl tellurol.

Suitable titanium sources include rutile and / or titanium oxide (TiO ₂ ), for example Degussa P-25, titanium isopropoxide, TiO (oxalate), TiO (acetylacetonate) ₂ , or titanium alkoxide complexes, 0.0 &gt; Tyzor &lt; / RTI &gt; 131. Suitable tin sources may include tin (II) acetate. Suitable germanium sources may include germanium (IV) oxide. Suitable zirconium sources may include zirconyl nitrate or zirconium (IV) oxide. Suitable hafnium sources may include hafnium (IV) chloride or hafnium (IV) oxide.

Suitable lanthanum sources may include lanthanum (III) chloride or lanthanum (III) oxide, and lanthanum (III) acetate hydrate. Suitable cerium sources may include cerium (III) acetate hydrate. Suitable sources of praseodymium may include praseodymium (III) chloride, praseodymium (III, IV) oxide or praseodymium (III) isopropoxide, and praseodymium (III) acetate hydrate. Suitable neodymium sources may include neodymium (III) chloride, neodymium (III) oxide or neodymium (III) isopropoxide, and neodymium (III) acetate hydrate. Suitable sources of samarium sources may include samarium (III) chloride, samarium (III) oxide or samarium (III) isopropoxide, and samarium (III) acetate hydrate. Suitable europium sources may include europium (II) chloride, europium (III) chloride or europium (III) oxide, and europium (III) acetate hydrate. Suitable gadolinium sources may include gadolinium (III) chloride or gadolinium (III) oxide, and gadolinium (III) acetate hydrate. Suitable terbium sources may include terbium (III) chloride or terbium (III) oxide, and terbium (III) acetate hydrate. Suitable dysprosium sources may include dysprosium (III) chloride, dysprosium (III) oxide or dysprosium (III) isopropoxide, and dysprosium (III) acetate hydrate. Suitable sources of holmium may include holmium (III) chloride, holmium (III) oxide or holmium (III) acetate hydrate. Suitable sources of erbium may include erbium (III) chloride, erbium (III) oxide or erbium (III) isopropoxide, and erbium (III) acetate hydrate. A suitable source of tulip sources may comprise tulip (III) chloride or tulip (III) oxide, and tulip (III) acetate hydrate. Suitable ether bum sources may include ether bimide (III) chloride, ether bimide (III) oxide or ether bimide (III) isopropoxide, and ether bimide (III) acetate hydrate. Suitable lutetium sources may include lutetium (III) chloride or lutetium (III) oxide, and lutetium (III) acetate hydrate lutetium. Nitrides of the above listed metals may also be used as the source compound.

Solvents which can be used in the preparation of the mixed metal oxides according to the invention include water, alcohols such as methanol, ethanol, propanol, diols (for example ethylene glycol, propylene glycol), organic acids such as acetic acid, But not limited to, other polar solvents. In one or more embodiments, the metal source compound is at least partially soluble in the solvent, at least at reaction temperature and pressure, and in some embodiments, the metal source compound is slightly soluble in the solvent. In one or more embodiments, water is a solvent. Water suitable for use in chemical synthesis may be used. The water may be distilled and / or deionized water, but it is not necessary.

The amount of aqueous solvent in the reaction medium may vary due to the solubility of the source compound being combined in forming the particular mixed metal oxide. The amount of aqueous solvent should be sufficient to obtain at least a slurry of the reactants (mixture of liquid and solid that can be stirred). In the hydrothermal synthesis of the mixed metal oxide, it is typical to leave an amount of void portion in the reactor vessel.

Changes to the method will be appreciated by those skilled in the art. For example, the catalyst preparation process described herein having the formula:

_{Mo V 0 .1-0.3 Sb 0 .1-0.3 Nb} 0 .03-0.15 Te 0 .01-0.03 Ti 0 .05-0.25 L e O n

E "is more than 0 and less than about 0.02, and" e " is more than 0 and less than about 0.02, and L is a mixture of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, quot; n "is determined by the oxidation state of the other element) to produce a solution or slurry of the source compound to the catalyst. In one or the first slurry, molybdenum trioxide (MoO ₃ ), antimony oxide (Sb ₂ O ₃ ), telluric acid (Te (OH) ₆ ), titanium dioxide (TiO ₂ ), and one or more "L" And then dissolved / slurried in water at the desired ratio (all ratios are for the molybdenum metal). In another or a second solution or slurry, vanadium oxysulfate (VOSO ₄ ) is dissolved / slurried in water. In an alternative embodiment, the vanadium oxysulfate can be added as a solid. In another or third solution or slurry, niobic acid (Nb ₂ O ₅ .nH ₂ O) is mixed with oxalic acid (HO ₂ CCO ₂ H). Oxalic acid: niobium molar ratio may be applied. In one embodiment, the oxalic acid: niobium molar ratio is about 3: 1. The three solutions / slurries are combined with one another, heated to 175 ° C while mixing, held at this temperature for 67 hours, and then cooled to room temperature, typically by natural heat loss. The cooled slurry is filtered, the mother liquor is removed, the remaining solids are washed and then calcined at 600 ° C under nitrogen to activate the catalyst. The calcined catalyst is pulverized and then pelletized and sized or spray dried for testing and / or ultimate use.

Ammonia  Conversion of propane and isobutane through oxidation and oxidation

In one or more embodiments, one or more of the above-described catalysts is provided to a gas phase flow reactor and oxygen (e.g., oxygen-containing gas such as air, typically air) is introduced into the reaction vessel under reaction conditions effective to form acrylonitrile or methacrylonitrile And contacting the catalyst with propane or isobutane in the presence of ammonia to convert the propane to acrylonitrile and / or to convert the isobutane to methacrylonitrile. In some embodiments, the feed stream comprises propane or isobutane, an oxygen-containing gas such as air, and ammonia, depending on the molar ratio below. In one or more embodiments, the molar ratio of propane or isobutane to oxygen is from about 0.125 to about 5, in other embodiments from about 0.25 to about 4, and in yet other embodiments from about 0.5 to about 3.5. In one or more embodiments, the molar ratio of propane or isobutane to ammonia is from about 0.3 to about 2.5, and in other embodiments from about 0.5 to about 2.0. The feedstream may also include one or more additional feed components, including acrylonitrile or methacrylonitrile products (e.g., from a recycle stream or from an initial stage of a multi-stage reactor), and / or Steam is included. For example, the feed stream may comprise from about 5% to about 30% by weight, based on the total amount of feed stream, of one or more additional feed components, or from about 5 to about 30 moles per mole of propane or isobutane in the feed stream . In one embodiment, the catalyst compositions described herein are applied in a once-through process, i.e., in a manner that does not recycle unreacted feed material, but recycles propane to acrylonitrile to ammonia oxidation do.

The propane may also provide a gas phase flow reactor with one or more of the catalysts described above and provide a reaction zone to the source stream comprising oxygen-containing gas, such as typically air, under reaction conditions effective to form acrylic acid Acrylic acid and isobutane can be converted to methacrylic acid by contacting the catalyst with propane. The source stream for the reaction preferably comprises an oxygen-containing gas, such as propane and air, in a molar ratio of propane or isobutane to oxygen ranging from about 0.15 to about 5, and preferably from about 0.25 to about 2, . The feed stream may also contain one or more additional feed components, including acrylic acid or methacrylic acid products (e.g., from a recycle stream, or from an initial stage of a multi-stage reactor), and / . For example, the feed steam may comprise from about 5 wt% to about 30 wt%, based on the total amount of feed stream, or from about 5 mol to about 30 mol, relative to the amount of propane or isobutane in the feed stream.

The specific design of the gas phase flow reactor is not strictly critical. Thus, the gas phase flow reactor may be a stationary phase reactor, a fluidized bed reactor, or another type of reactor. The reactor may be a single reactor, or it may be one reactor in a multi-stage reactor system. In one or more embodiments, the reactor comprises at least one feed inlet for feeding the reactant feed stream to the reaction zone of the reactor, a reaction zone comprising the mixed metal oxide catalyst, and an outlet for discharging the reaction product and the unreacted reactant .

The reaction conditions are adjusted to be effective to convert propane to acrylonitrile or acrylic acid, or isobutane to methacrylonitrile or methacrylic acid. Generally, the reaction conditions are from about 300 ° C to about 550 ° C, in one or more embodiments from about 325 ° C to about 500 ° C, in some embodiments from about 350 ° C to about 450 ° C, and in other embodiments from about 430 ° C to about 520 ° C Range of temperature. The pressure of the reaction zone may be adjusted to a range from about 0 psig to about 200 psig, in one or more embodiments from about 0 psig to about 100 psig, and in some embodiments from about 0 psig to about 50 psig.

Generally, the flow rate of propane or isobutane containing the feed stream through the reaction zone of the gas phase flow reactor ranges from about 0.02 to about 5, in some embodiments from about 0.05 to about 1, and in other embodiments from about 0.1 to about 0.5 Can be adjusted to provide a weight hourly space velocity (WHSV) of the range, which can be adjusted in each case, for example, to g of propane or isobutane per gram of catalyst. In one or more embodiments, advantageous catalyst performance appears when the WHSV is greater than or equal to about 0.1, in other embodiments greater than or equal to about 0.15, and in yet other embodiments, greater than or equal to about 0.2.

The resulting acrylonitrile and / or acrylic acid and / or methacrylonitrile and / or methacrylic acid product can be isolated, if necessary, from other by-products and / or unreacted reactants according to methods known in the art.

One or more embodiments of the present invention can produce a yield of acrylonitrile of at least about 57% when a single phase (i.e., no recycle) propane is applied to ammonia oxidation. Certain embodiments of the present invention are capable of producing a yield of acrylonitrile of at least about 59% when single (i.e., no recycle) propane is applied to ammonia oxidation. Other embodiments of the present invention are capable of producing a yield of acrylonitrile of at least about 61% when single (i.e., no recycle) propane is applied to ammonia oxidation. The effluent of the reactor is also CO _x (carbon dioxide + carbon monoxide), hydrogen cyanide (HCN), acetonitrile or methyl cyanide (CH ₃ CN), unreacted oxygen (O _2), ammonia (NH _3), nitrogen (N ₂ ), helium (He), and co-entrained catalyst fine (fine).

Advantageously, the catalyst composition of the present invention differs from the tellurium-containing catalyst described in the literature in that the catalyst composition of the present invention does not exhibit any observable tellurium disappearance from the active phase when prepared and tested under the conditions described above Do. For example, in one or more embodiments, when the catalyst composition of the present invention is calcined under nitrogen at a temperature of about 600 &lt; 0 &gt; C for about 2 hours, no observable tellurium deposits are present in the calcining vessel or furnace. The catalyst compositions of the present invention exhibit improved stability compared to other tellurium-containing catalysts. This improved stability provides little degradation in catalytic performance over time on-stream, and also allows the catalyst to maintain good performance at higher space velocities.

certain Example

To illustrate the invention, mixed metal oxide catalysts were prepared and then evaluated under various reaction conditions. The compositions listed below are nominal compositions and are based on the total metal added to the catalyst formulation. The actual composition of the finished catalyst may differ slightly from the nominal composition shown below, as some metals may be lost during the catalyst preparation or can not be completely reacted.

Example # 1 - Mo ₁ V _{0 .3} Sb _{0 .175} Nb _{0 .06} Te _{0 .02} Ti _{0 .1} Nd _{0 .005} O _n

125 mL MoO Teflon reactor liner _{3 (8.0 g), Sb 2} O 3 (1.418 g), TiO 2 (0.444 g), Te (OH) 6 (0.255 g), and Nd (OAc) ₃ (2.78 mL of 0.1 M solution) and water (10 mL). As used in this and several subsequent examples, "(OAc) ₃ " designates the acetate hydrate for the nominal lanthanide metal. The mixture was stirred for about 5 minutes and then VOSO ₄ (16.67 mL of a 1 M solution) and niobium oxalate (7.39 mL of a 0.451 M solution wherein the molar ratio of oxalate to niobium was about 3/1) Respectively. Water was added to obtain about 80% fill volume in the reactor liner. Next, the reactor was sealed in a metal housing with a Teflon cap, left in an oven preheated to 175 占 폚, and rotated continuously to effect mixing of liquid and solid reagents. After 67 hours, the reactor was cooled and the Teflon liner was removed from the housing. The product slurry was stirred for 2 minutes, then vacuum-filtered using glass frit, and washed with 3 portions of 200 mL of water. The wet solid was then dried at 120 &lt; 0 &gt; C for 12 hours. Milling the resulting solid material, which was then baked for 2 hours at 600 ℃ under N _2. The solids were then ground, pressed, and sieved to a particle size range of 145 to 355 microns and tested for catalyst performance. The material has a nominal composition Mo ₁ V _{0 .3} Sb _{0 .175} Nb _{0 .06} Te _{0 .02} Ti _{0 .1} Nd _{0 .005} O _n .

This material was tested as a catalyst for the ammonia oxidation of propane to acrylonitrile. 420 ℃, WHSV = 0.2 and feed ratio _{C 3 H 8 / NH 3 /} O 2 / He = 1 / 1.2 / 3/ 12, the acrylonitrile of 61% acrylic yield was obtained (89% propane conversion, 68% acrylic Ronitril selectivity).

Example # 2 - Mo ₁ V _{0 .3} Sb _{0 .18} Nb _{0 .08} Te _{0 .02} Ti _{0 .1} Li _{0 .016} Nd _{0 .005} O _n

A first material was prepared as follows. To a 23 mL Teflon reactor liner were added MoO ₃ (1.152 g), VOSO ₄ (2.30 mL of a 1.04 M solution), niobium oxalate (1.60 mL of a 0.40 M solution wherein the oxalate to niobium molar ratio was about 3/1) _{, Sb 2 O 3 (2.93 mL} 0.49 M slurry of _{a), TiO 2 (2.85 mL 0.28} M slurry of a), Li (OAc) (1.00 mL 0.40 M _{solution), Te (OH) 6 (} 0.20 M solution of 0.80 mL ), And Nd (OAc) ₃ (1.00 mL of a 0.04 M solution). Water was added to obtain about 60% fill volume in the reactor liner. Next, the reactor was sealed in a Teflon cap in a metal housing, left in an oven preheated to 175 占 폚, and rotated continuously to effect mixing of liquid and solid reagents. After 48 hours, the reactor was cooled and the Teflon liner was removed from the housing. The product slurry was stirred for 2 minutes, then vacuum-filtered using a glass frit and washed with 3 portions of 3 portions by addition of 150 mL of water. The wet solids were then dried in air at 90 &lt; 0 &gt; C for 12 hours. Milling the resulting solid material, which was then baked for 2 hours at 600 ℃ under N _2. The material has a nominal composition Mo ₁ V _0.3 Sb _0.18 Nb _0.08 Te _0.02 Ti _0.1 Li _0.05 Nd _0.005 O _n .

A second material was prepared as described for the first material, except that lithium acetate was omitted. The second material has a nominal composition Mo ₁ V _0.3 Sb _0.18 Nb _0.08 Te _0.02 Ti _0.1 Nd _0.005 O _n .

0.45 g of the first material and 0.94 g of the second material were combined to form a sample having the nominal composition Mo ₁ V _0.3 Sb _0.18 Nb _0.08 Te _0.02 Ti _0.1 Li _0.016 Nd _0.005 O _n . Next, the solid was pulverized, pressed, and sieved to a particle size of 145 to 355 microns and tested for catalyst performance.

This material was tested as a catalyst for the ammonia oxidation of propane to acrylonitrile. 60% acrylonitrile yield was obtained at 433 ° C, WHSV = 0.2 and feed ratio C ₃ H ₈ / NH ₃ / O ₂ / He = 1 / 2.0 / 3/12 (91% propane conversion, 65% Ronitril selectivity).

Comparative Example # 3 - Mo ₁ V _{0 .3} Sb _{0 .2} Nb _{0 .06} Ti _{0 .1} Nd _{0 .005} O _n

MoO ₃ (8.0 g), Sb ₂ O ₃ (1.620 g), TiO ₂ (0.444 g), and Nd (OAc) ₃ (0.0893 g) and water (10 mL) were loaded into a 125 mL Teflon reactor liner. The mixture was stirred for about 5 minutes and then VOSO ₄ (16.67 mL of a 1 M solution) and niobium oxalate (7.612 mL of a 0.438 M solution wherein the oxalate to niobium molar ratio was about 3/1) . Water was added to obtain about 80% fill volume in the reactor liner. Next, the reactor was sealed in a Teflon cap in a metal housing, left in an oven preheated to 175 占 폚, and rotated continuously to effect mixing of liquid and solid reagents. After 48 hours, the reactor was cooled and the Teflon liner was removed from the housing. The product slurry was stirred for 2 minutes, then vacuum-filtered using a glass frit and washed with 3 portions of 200 mL of water. The wet solids were then dried in air at 120 &lt; 0 &gt; C for 12 hours. Milling the resulting solid material, which was then baked for 2 hours at 600 ℃ under N _2. The solid was then ground, pressed and sieved to a particle size of 145 to 355 microns and tested for catalyst performance. The material has a nominal composition Mo ₁ V _{0 .3} Sb _{0 .2} Nb _{0 .06} Ti _{0 .1} Nd _{0 .005} O _n .

This material was tested as a catalyst for the ammonia oxidation of propane to acrylonitrile. 56% acrylonitrile yield was obtained at 430 ° C, WHSV = 0.15 and feed ratio C ₃ H ₈ / NH ₃ / O ₂ / He = 1 / 1.2 / 3/12 (87% propane conversion, 64% Ronitril selectivity).

Comparative Example # 4 - Mo ₁ V _{0 .38} Sb _{0 .25} Nb _{0 .075} Ti _{0 .125} Nd _{0 .0062} O _n

MoO ₃ (6.334 g), Sb ₂ O ₃ (1.283 g), TiO ₂ (0.351 g), Nd (OAc) ₃ (0.088 g) and water (10 mL) were loaded into a 200 mL Teflon reactor liner. The mixture was stirred for about 5 minutes and then VOSO ₄ (13.2 mL of a 1.0 M solution) and niobium oxalate (6.083 mL of a 0.434 M solution) were introduced. Water was added to obtain about 80% fill volume in the reactor liner. Next, the reactor was sealed in a Teflon cap in a metal housing, left in an oven preheated to 175 占 폚, and rotated continuously to effect mixing of liquid and solid reagents. After 48 hours, the reactor was cooled and the Teflon liner was removed from the housing. The product slurry was centrifuged to separate the solid reaction product from the liquid. The liquid was decanted and distilled water (25 mL) was added to the solid. The solids were ground and shaken to dissolve the soluble salts. The mixture was centrifuged and the liquid was decanted. The washing was carried out twice. The wet solid was dried in air at 120 &lt; 0 &gt; C for 12 hours. Milling the resulting solid material, which was then baked for 2 hours at 600 ℃ under N _2. The solid was then ground, pressed and sieved to a particle size of 145 to 355 microns and tested for catalyst performance. The material has a nominal composition Mo ₁ V _{0 .38} Sb _{0 .25} Nb _{0 .075} Ti _{0 .125} Nd _{0 .0062} O _n .

This material was tested as a catalyst for the ammonia oxidation of propane to acrylonitrile. 420 ℃, WHSV = 0.15 and feed ratio _{C 3 H 8 / NH 3 /} O 2 / He = 1 / 1.2 / 3/ 12, the acrylonitrile of 58% acrylic yield was obtained (84% propane conversion, 69% acrylic Ronitril selectivity).

Comparative Example # 5 - Mo ₁ V _{0 .3} Sb _{0 .2} Nb _{0 .06} Ti _{0 .1} Ge _{0 .05} Nd _{0 .005} O _n

MoO ₃ (1.20 g), Sb ₂ O ₃ (0.243 g), GeO ₂ (0.0436 g) and water (2.0 mL) were loaded into a 23 mL Teflon reactor liner. The mixture was stirred for about 5 minutes and then treated with VOSO ₄ (2.50 mL of a 1.0 M solution), TiO ₂ (0.833 mL of a 0.08 g / mL slurry), Nd (OAc) ₃ (0.417 mL of a 0.1 M solution) Oxalate (1.142 mL of a 0.438 M solution). Water was added to obtain about 80% charged volume of the reactor liner. Next, the reactor was sealed in a Teflon cap in a metal housing, left in an oven preheated to 175 占 폚, and rotated continuously to effect mixing of liquid and solid reagents. After 48 hours, the reactor was cooled and the Teflon liner was removed from the housing. The product slurry was centrifuged to separate the solid reaction product from the liquid. The liquid was decanted and distilled water (5 mL) was added to the solid. The solids were ground and shaken to dissolve the soluble salts. The mixture was centrifuged and the liquid was decanted. The washing was carried out twice. The wet solid was dried in air at 120 &lt; 0 &gt; C for 12 hours. Milling the resulting solid material, which was then baked for 2 hours at 600 ℃ under N _2. The solid was then ground, pressed and sieved to a particle size of 145 to 355 microns and tested for catalyst performance. The material has a nominal composition Mo ₁ V _{0 .3} Sb _{0 .2} Nb _{0 .06} Ti _{0 .1} Ge _{0 .05} Nd _{0 .005} O _n .

This material was tested as a catalyst for the ammonia oxidation of propane to acrylonitrile. 420 ℃, WHSV = 0.15 and feed ratio _{C 3 H 8 / NH 3 /} O 2 / He = 1 / 1.2 / 3/ 12, the acrylonitrile of 58% acrylic yield was obtained (84% propane conversion, 69% acrylic Ronitril selectivity).

Comparative Example # 6 and Example # 7

For Comparative Example 6, a base catalyst of the formula MoV _{0 .21} Sb _{0 .24} Nb _{0 .09} O _x / 45% SiO ₂ (hereinafter referred to as a "four component base" Was prepared by a firing method. Similarly, for example, by further adding the tellurium by using the impregnation method described herein in "quaternary-based" catalyst, # 7, of the formula _{MoV 0.21 Sb 0.24 Te 0.04 Nb 0.09} O x / 45% SiO 2 Catalyst.

Comparative Examples # 8 and # 9 and Examples # 10 to # 12

For Comparative Example # 8, the formula MoV _{0 .3} Sb _{0 .2} (hereafter referred to as the "base component _{6") Nb 0 .08 Ti 0 .1} Ce 0 .005 O x / 45% base catalyst of SiO ₂ Non-hydrothermal process and the calcination process described herein. Similarly, for Comparative Example # 9 and Examples # 10 to # 12, tellurium was added to the "six component base" catalyst using the impregnation method described herein, A catalyst composition was prepared.

Comparative Example # 9: MoV _{0 .3} Sb _{0 .2} Te _{0 .06} Nb _{0 .08} Ti _{0 .1} Ce _{0 .005} O _x / 45% SiO ₂

Example # 10: MoV _{0 .3} Sb _{0 .2} Te _{0 .04} Nb _{0 .08} Ti _{0 .1} Ce _{0 .005} O _x / 45% SiO ₂

Example # 11: MoV _{0 .3} Sb _{0 .2} Te _{0 .03} Nb _{0 .08} Ti _{0 .1} Ce _{0 .005} O _x / 45% SiO ₂

Example # 12: and _{MoV 0 .3 Sb 0 .2 Te 0} .02 Nb 0 .08 Ti 0 .1 Ce 0 .005 O x / 45% SiO 2

The catalysts of Comparative Examples # 6 and # 8 and Examples 7 and # 9 to # 12 were tested in a 40 cc laboratory fluidized bed reactor with a diameter of 1 inch. The reactor was charged with about 20 to about 45 grams of particulate catalyst or catalyst mixture. Propane was fed to the reactor at a rate of about 0.04 to about 0.15 WHSV. The pressure in the reactor was maintained at about 2 to about 15 psig. The reaction temperature ranged from about 420 to about 460 ° C. Generally, ammonia was fed to the reactor at a flow rate such that the ammonia to propane ratio was from about 1 to about 1.5. Oxygen was fed to the reactor at a flow rate such that the oxygen to propane ratio was about 3.4. Nitrogen was fed to the reactor at a flow rate such that the nitrogen to propane ratio was about 12.6. Test results for the catalysts of Comparative Examples # 6 and # 8 and Examples 7 and # 9 to # 12 are summarized in Table 1 below.

Comparative Example # 13 and Examples # 14 and # 15

For comparative example # 13, the base catalyst of the formula MoV _{0 .25} Sb _{0 .167} Nb _{0 .08} Nd _{0 .002} Ce _{0 .003} Li _{0 .013} O _x / 45% SiO ₂ was prepared by the non- Were prepared by the described firing method. Similarly, for the # 14 to # 15, for example, the catalytic compositions shown below were prepared with the addition of tellurium to the catalyst using the impregnation method described herein, varying the tellurium content.

Example _{# 14: MoV 0 .25 Sb 0} .167 Te 0 .02 Nb 0 .08 Nd 0 .002 Ce 0 .003 Li 0 .013 O x / 45% SiO 2

Example _{# 15: MoV 0 .25 Sb 0} .167 Te 0 .04 Nb 0 .08 Nd 0 .002 Ce 0 .003 Li 0 .013 O x / 45% SiO 2

For the catalyst of Comparative Example # 13 and Examples # 14 and # 15, additional antimony (0.08 mol Sb / 1 mol Mo) was added to the catalyst by dusting the catalyst with Sb ₂ O ₃ . The catalyst was then tested in a 40 cc laboratory fluidized bed reactor under the same conditions described above for Comparative Examples # 6 and # 8 and Examples # 7 and # 9 to # 12. Test results for the catalysts of Comparative Examples # 13 and # 14 and # 15 are summarized in Table 2 below.

As used in Table 1 and Table 2 above and as used in this application, "temperature" is the reactor temperature in degrees Celsius. "TIS" is "flow time" The "C3 concentration" is mole% per propane pass conversion to all products and byproducts. "AN sel" means acrylonitrile selectivity in%, expressed as the ratio of the number of moles of acrylonitrile produced to the number of propane moles converted. "AN yield" means acrylonitrile yield and is in mole% per pass conversion of propane to acrylonitrile. "WHSV" means the weight hourly space velocity of propane fed to the reactor, expressed as propane weight per catalyst weight per hour, and also expressed as "wwh". While the foregoing detailed description and the foregoing embodiments are typical of the practice of the invention, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in view of this disclosure. Accordingly, all such alternatives, modifications and variations are intended to be included within the spirit and broad scope of the appended claims.

Claims (25)

A process for producing an unsaturated nitrile, comprising contacting a mixture of saturated or unsaturated hydrocarbons or saturated and unsaturated hydrocarbons with ammonia and an oxygen-containing gas in the presence of a catalyst composition comprising a mixed oxide of the formula: Ammonia oxidation of unsaturated hydrocarbons or mixtures of saturated and unsaturated hydrocarbons: Mo _l V _a Sb _b Nb _c Te _d X _e L _f o _n Wherein X is selected from the group consisting of Ti, Sn, Ge, Zr, Hf, and mixtures thereof; L is selected from the group consisting of Pr, Nd and mixtures thereof; 0.1 < a < 0.8, 0.01 < b < 0.6, 0.001 < c < 0.3, 0.001 < d < 0.06, 0 < e &lt; 0.6, 0 < f <0.1; n is the number of oxygen atoms necessary to meet the valence requirement of all other elements present in the mixed oxide, provided that at least one other element of the mixed oxide may be in a lower oxidation state than its highest oxidation state And a, b, c, d, e and f represent molar ratios of the corresponding elements to 1 mol of Mo). The method of claim 1, wherein the catalyst composition is: 0.2 <a <0.4, 0.1 <b <0.4, 0.01 <c <0.2, 0.002 <d ≦ 0.05, 0.001 <e <0.3, 0.05. The method of claim 1, wherein X is selected from the group consisting of element Ti, Sn, and mixtures thereof. delete The method of claim 1, wherein the catalyst composition comprises a support selected from the group consisting of silica, alumina, zirconia, titania, or mixtures thereof. 6. The process of claim 5, wherein the support comprises from 10% to 70% by weight of the catalyst. The method of claim 1, wherein the hydrocarbon comprises propane, isobutane, or a mixture thereof. The method of claim 1, wherein the method comprises providing a feed stream comprising a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons, ammonia, and an oxygen-containing gas, wherein the molar ratio of hydrocarbon to oxygen Is from 0.125 to 5. The method of claim 1, wherein the method comprises providing a feed stream comprising a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons, ammonia, and an oxygen-containing gas, wherein the molar ratio of hydrocarbon to ammonia Is from 0.3 to 2.5. The method of claim 1, wherein the process provides a feed stream comprising a saturated hydrocarbon or a mixture of unsaturated hydrocarbons or saturated and unsaturated hydrocarbons at a flow rate adjusted to provide a space velocity in weight of at least 0.1 g of hydrocarbon relative to the catalyst g &Lt; / RTI &gt; The process according to claim 1, wherein the process provides a feed stream comprising a mixture of saturated or unsaturated hydrocarbons or saturated and unsaturated hydrocarbons at a flow rate adjusted to provide a space velocity in weight of at least 0.15 g of hydrocarbon relative to the catalyst g &Lt; / RTI &gt; The method of claim 1 wherein the process provides a feed stream comprising a mixture of saturated or unsaturated hydrocarbons or saturated and unsaturated hydrocarbons at a flow rate that is adjusted to provide a weight hourly space velocity of at least 0.2 g of hydrocarbon relative to the catalyst g &Lt; / RTI &gt; A process for producing an unsaturated nitrile, comprising contacting a mixture of saturated or unsaturated hydrocarbons or saturated and unsaturated hydrocarbons with ammonia and an oxygen-containing gas in the presence of a catalyst composition comprising a mixed oxide of the formula: Ammonia oxidation of unsaturated hydrocarbons or mixtures of saturated and unsaturated hydrocarbons: Mo _l V _a Sb _b Nb _c Te _d X _e L _{f g} Li _h O _n Wherein X is selected from the group consisting of Ti, Sn, Ge, Zr, Hf, and mixtures thereof; L is selected from the group consisting of Pr and Nd and mixtures thereof; A is at least one of Na, K, Cs, Rb and mixtures thereof; 0.1 < a < 0.8, 0.01 < b < 0.6, 0.001 < c < 0.3, 0.001 < d < 0.06, 0 < e &lt; 0.6, 0 < f < 0.1, 0 < g &lt; 0.1, 0 < h <0.1; n is the number of oxygen atoms necessary to meet the valence requirements of all other elements present in the mixed oxide, provided that at least one other element of the mixed oxide may be in a lower oxidation state than its highest oxidation state, b, c, d, e, f, g and h represent the molar ratio of the corresponding element to 1 mole of Mo). 14. The method of claim 13, wherein the catalyst composition is: 0.2 < a < 0.4, 0.1 < b < 0.4, 0.01 & 14. The process according to claim 13, wherein the catalyst composition is: 0.03 < h < 0.06. 14. The method of claim 13 wherein X is selected from the group consisting of elemental Ti, Sn and mixtures thereof. delete 14. The method of claim 13, wherein the catalyst composition comprises a support selected from the group consisting of silica, alumina, zirconia, titania, or mixtures thereof. 19. The process of claim 18, wherein the support comprises from 10% to 70% by weight of the catalyst. The method of claim 1, wherein the catalyst composition is: 0.2 <a <0.4, 0.1 <b <0.4, 0.01 <c <0.2, 0.002 <d <0.06, 0? E <0.3, and 0 <f <0.05. The method of claim 1, wherein the catalyst composition is: 0.2 <a <0.4, 0.1 <b <0.4, 0.01 <c <0.2, 0.002 <d ≦ 0.05, 0 ≦ e <0.3, and 0.001 <f <0.05. The method of claim 1, wherein the catalyst composition is: 0.2 <a <0.4, 0.1 <b <0.4, 0.01 <c <0.2, 0.002 <d ≦ 0.05, 0.001 <e <0.3, and 0 <f <0.05. 14. The process according to claim 13, wherein the catalyst composition is as follows: 0.2 < a < 0.4, 0.1 < b < 0.4, 0.01 <c <0.2, 0.002 <d <0.06, 0 e <0.3 and 0 <f <0.05. The method of claim 1, wherein the catalyst composition is: 0.2 <a <0.4, 0.1 <b <0.4, 0.01 <c <0.2, 0.002 <d ≦ 0.05, 0 ≦ e <0.3, and 0.001 <f <0.05. 14. The process of claim 13, wherein the catalyst composition is: 0.2 < a < 0.4, 0.1 < b < 0.4, 0.01 < c < 0.2, 0.002 < d 0.05, 0.001 &