RU2451548C2 - Method for oxidative ammonolysis of propane and isobutane in presence of mixed metal oxide catalysts - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method for oxidative ammonolysis in the presence of mixed metal oxide catalysts. The method for oxidative ammonolysis to obtain an unsaturated nitrile involves bringing saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbon with ammonia and an oxygen-containing gas in the presence of a catalyst composition containing molybdenum, vanadium, antimony, niobium, tellurium, at least one element selected from a group consisting of titanium, tin, germanium, zirconium, hafnium and mixtures thereof, at least one lanthanide selected from a group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium and mixtures thereof. Disclosed is a version of the method for oxidative ammonolysis, where the catalyst contains, in addition to the listed elements, lithium and an element selected from sodium, caesium, rubidium and mixture thereof.

EFFECT: catalysts are characterised by very low content of tellurium in the composition, catalyst compositions are effective in gas-phase conversion of propane to acrylonitrile and isobutane to methacrylonitrile.

25 cl, 2 tbl, 15 ex

Description

Technical field

The present invention generally relates to a process for the oxidative ammonolysis or oxidation of a saturated or unsaturated hydrocarbon to produce an unsaturated nitrile or unsaturated organic acid.

In particular, the invention relates to a method for the gas-phase conversion of propane to acrylonitrile and isobutane to methacrylonitrile (by oxidative ammonolysis) or propane to acrylic acid and isobutane to methacrylic acid (by oxidation).

Description of the Related Art

Mixed metal oxide catalysts have been widely used to convert propane to acrylonitrile and isobutane to methacrylonitrile (by oxidative ammonolysis) and / or to convert propane to acrylic acid (by oxidation). This technical field includes numerous patents and patent applications, including, for example, US patent No. 5750760, Ushikubo and others, US patent No. 6036880, Komada and others, US patent No. 6043186, Komada and others, US patent No. 6143916 , Hinago et al., US Patent No. 6,514,902, Inoue et al., US Patent Application No. 2003/0088118 Al, Komada et al., US Patent Application No. 2004/0063990 Al, Gaffhey et al. And PCT Patent Application No. WO 2004 / 108278 Al, Asahi Kasei Kabushiki Kaisha.

Although progress has been made in this area through the development of catalysts based on molybdenum, vanadium, antimony and niobium, effective in converting propane to acrylonitrile and isobutane to methacrylonitrile (by oxidative ammonolysis) and / or converting propane to acrylic acid and isobutane to methacrylic acid (by oxidation), however, the catalysts proposed for industrial use need further improvement. In general, catalytic reactions known in the art produce low yields of desired products.

At those temperatures at which oxidative ammonolysis of propane and isobutane and / or the conversion of propane to acrylic acid and isobutane to methacrylic acid (by oxidation) is carried out, tellurium can volatilize. Catalysts containing relatively large amounts of tellurium lose tellurium during oxidative ammonolysis or oxidation, which adversely affects the activity of the catalysts.

SUMMARY OF THE INVENTION

In one aspect, the present invention relates to a method for the oxidative ammonolysis of a saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons to produce an unsaturated nitrile, the method comprising contacting a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons with ammonia and an oxygen-containing gas in the presence of a catalyst composition containing molybdenum, vanadium, antimony, niobium, tellurium, optionally at least one element, which the selected one is from the group consisting of titanium, tin, germanium, zirconium and hafnium, and optionally at least one lanthanide, which is selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. The catalyst composition used in this process is characterized by relatively low tellurium concentrations.

In one embodiment, the present invention is a method for converting a hydrocarbon that is selected from the group consisting of propane, isobutane or mixtures thereof to acrylonitrile, methacrylonitrile or mixtures thereof, the method comprising the step of reacting, at elevated temperature, the vapor phase of said hydrocarbon with a gas containing molecular oxygen, and ammonia in the presence of a catalytic composition comprising molybdenum, vanadium, antimony, niobium, tellurium, optionally at least one lanthanide selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

In another aspect, the present invention also relates to catalyst compositions comprising molybdenum, vanadium, antimony, niobium, tellurium, optionally at least one element selected from the group consisting of titanium, tin, germanium, zirconium and hafnium, and optionally at least at least one lanthanide selected from lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

In one embodiment, the catalyst composition is a mixed oxide of empirical formula:

Mo ₁ V _a Sb _b Nb _c Te _d X _c L _f O _n ,

where 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 <0.6,

0 <f <0.1; and

n is the number of carbon atoms necessary to saturate the valency of all other elements of the mixed oxide, provided that one or more other elements in the mixed oxide can be in an oxidation state lower than the higher oxidation state, and

a, b, c, d, e and f represent the ratio of the number of moles of the corresponding elements to the number of moles of Mo. In other embodiments, X is Ti, Sn, or mixtures thereof. In other embodiments, L is Nd, Ce, or Pr.

DETAILED DESCRIPTION OF THE INVENTION

In general, the present invention relates to a method for the oxidative ammonolysis of a saturated or unsaturated hydrocarbon, and catalyst compositions can be used in this method. Such methods are effective for the oxidative ammonolysis of propane to acrylonitrile and isobutane to methacrylonitrile and / or the conversion of propane to acrylic acid and isobutane to methacrylic acid (by oxidation).

Catalytic composition

In one embodiment, the catalyst composition used in the method of the present invention comprises molybdenum, vanadium, antimony, niobium, tellurium, optionally at least one element selected from the group consisting of titanium, tin, germanium, zirconium and hafnium, and optionally one lanthanide selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. In addition, for the catalytic composition used in this method, an important characteristic is the relative concentration of tellurium; and in one embodiment, the molar ratio of molybdenum to tellurium (Mo: Te) is in the range between 1: 0.001 and 1: 0.06. In another embodiment, the molar ratio of molybdenum to tellurium (Mo: Te) is in the range between 1: 0.001 to 1: 0.05. The term “at least one element selected from the group ...” or “at least one lanthanide selected from the group ...” as used herein includes mixtures of two or more of these elements or lanthanides, respectively.

In one embodiment, the catalyst composition is a mixed oxide of empirical formula:

Mo ₁ V _a Sb _b Nb _c Te _a X _e L _f O _n ,

where 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 <0.6,

0 <f <0.1; and

n is the number of oxygen atoms needed to saturate the valency of all other elements of the mixed oxide, provided that one or more other elements in the mixed oxide can be in an oxidation state lower than the highest oxidation state, and

a, b, c, d, e and f represent the ratio of the number of moles of the corresponding elements to the number of moles of Mo. In one embodiment, the catalyst composition is a mixed oxide of empirical formula:

Mo ₁ V _a Sb _b Nb _c Te _d X _e L _f O _n ,

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

L is selected from the group consisting of La, Ce, Pi, 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 <0.6,

0 <f <0.1; and

n is the number of oxygen atoms needed to saturate the valency of all other elements of the mixed oxide, provided that one or more other elements in the mixed oxide can be in an oxidation state lower than the highest oxidation state, and

a, b, c, d, e and f represent the ratio of the number of moles of the corresponding elements to the number of moles of Mo.

In other embodiments of the catalyst compositions described by the empirical formula, X is Ti or Sn. In other embodiments of the catalyst compositions described by the empirical formula, X is Ti, X is Sn, X is Ge, X is Zr, and X is Hf.

In other embodiments of the catalyst compositions described by the empirical formulas given above, L is Nd, Ce, or Pr. In other embodiments, L is Nd or Pr. In other embodiments of the catalytic compositions described by the empirical formulas given above, L is equal to La, L is Ce, L is Pr, L is Nd, L is Sm, L is Eu, L is Gd, L is Tb, L is Dy, L is equal to But , L is Er, L is Tm, L is Yb, and L is Lu.

In another embodiment of the catalyst compositions described by the empirical formulas given above, the catalyst composition does not contain tantalum.

In other versions of the catalytic compositions described by the empirical formulas a, b, c, d, e, and f each are independently in the following ranges: 0.1 <a, 0.2 <a, a <0.4, a <0.8, 0.01 <b, 0.1 <b, b <0.3, b <0.4, b <0.6, 0.001 <c, 0.01 <c, 0.02 <c, 0.03 <c, 0.04 <c, c <0.1, c <0.12, c <0.15, c <0.2 , c <0.3, 0.001 <d, 0.002 <d, 0.005 <d, d <0.025, d <0.025, d <0.03, d <0.03, d <0.04, d <0.04, d <0.05, d <0.05, d <0.055, 0 <e, 0.001 <e, 0.002 <e, e <0.05, e <0.1, e <0.15, e <0.2, e <0.3, e <0.6 and 0 <f, 0.001 <f, 0.002 <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 compositions described by the empirical formulas given above, the catalyst also contains lithium and may optionally contain one or more other alkali metals. In this embodiment, the catalyst composition is a mixed oxide of empirical formula

Mo ₁ V _a Sb _b Nb _c Te _d X _e L _f AgLi _h O _n ,

where X, L, a, b, c, d, e, f and n are described above, A represents at least one element of Na, K, Cs, Rb and mixtures thereof, 0 <g <0.1, 0 <h <0.1 and “g” and “h” represent the ratio of the number of moles of the corresponding element to the number of moles of Mo. In other embodiments of the mixed oxide catalyst composition described in the empirical formula above, the catalyst composition does not contain Na, K, Cs, Rb, or mixtures thereof (i.e., g is 0). In other embodiments of the catalytic composition, which is a mixed oxide described by the above empirical formula, 0 <h, 0.03 <h, h <0.06, h <0.1.

The catalyst of the present invention can be prepared either deposited or without a carrier (i.e., may include a carrier or may be a bulk catalyst). Suitable carriers are silica, alumina, zirconia, titanium oxide or mixtures thereof. However, when using zirconium or titanium oxides as carriers, the ratio of molybdenum to zirconium or titanium increases compared to the values indicated in the above formulas and fall in the range from 1: 1 to 1:10. Typically, the carrier serves as a binder for the catalyst, which leads to a catalyst that is more durable and more resistant to abrasion. However, in the case of industrial use of the catalyst, in order to achieve acceptable activity and strength (resistance to abrasion), it is important to find the desired ratio of the active phase (i.e., the complex of catalytically active oxides described above) and the support. A targeted increase in the amount of active phase reduces the strength of the catalyst. The support contains about 10-90% by weight of the supported catalyst. Typically, the carrier contains about 40-60 wt.% Supported catalyst. In one embodiment of the invention, only about 10% by weight of supported catalyst may be present on the support. In another embodiment, only about 30% by weight of supported catalyst may be present on the support. In yet another embodiment of the present invention, up to about 70% by weight of supported catalyst may be supported. There are carriers that may contain one or more promoters, for example, a silica sol containing sodium (Na), and such promoters can be introduced into the catalyst through the carrier. In one embodiment, the support is low sodium silica.

Catalyst Preparation

The catalyst of the present invention can be prepared in various ways. Two possible synthesis methods are described herein. The first synthesis method is carried out at approximately atmospheric pressure (hereinafter referred to as the non-hydrothermal synthesis method), while the second synthesis method is carried out at elevated pressures, usually in an autoclave (hereinafter referred to as the hydrothermal synthesis method). The non-hydrothermal synthesis method is described in US patents 6514902, US 7087551, US 109144, WO 2004/108278 and WO 2006/019078, which are incorporated herein by reference.

In one embodiment, the catalyst of the present invention can be prepared by non-hydrothermal synthesis as follows: ammonium heptamolybdate, ammonium metavanadate and antimony (III) oxide are added to water, the resulting mixture is heated to a temperature of at least 50 ° C and an aqueous mixture (A) is obtained. In this embodiment, it is heated with stirring. It is better to heat the aqueous mixture to a temperature in the range of 70 ° C to the normal boiling point of the mixture. You can heat with a reflux condenser. In the case of heating under reflux, the boiling point is usually in the range of about 101-102 ° C. Elevated temperatures can withstand for 0.5 hour or more. If the heating temperature is low (e.g. below 50 ° C), the heating time should be increased. In the case where the heating temperature is 80-100 ° C, heating usually lasts 1-5 hours.

After heating, a silica sol and hydrogen peroxide must be added to the aqueous mixture (A). Hydrogen peroxide is added to the aqueous mixture (A) in such an amount that the molar ratio of hydrogen peroxide to the antimony compound (molar ratio of H ₂ O ₂ / Sb) calculated as antimony is in the range of 0.01-20, in the range of 0.5-3, in the range of 1-2.5. After adding hydrogen peroxide, the aqueous mixture (A) is stirred at temperatures in the range of 30-70 ° C for a time of 30 minutes to 2 hours.

An aqueous liquid (B) is obtained by adding a niobium compound (e.g., niobic acid) to water, followed by heating the resulting mixture to a temperature in the range from 50 ° C to almost 100 ° C. It is better if the aqueous liquid (B) contains, in addition to the niobium compound, dicarboxylic acid (for example, oxalic acid). Typically, the molar ratio of dicarboxylic acid to niobium compound is in the range of 1-4, preferably in the range of 2-4. Those. in this case, niobic acid and oxalic acid are added to water, followed by heating and stirring the resulting mixture to form an aqueous liquid (B).

A convenient method for preparing said aqueous liquid (B) comprises the following steps: (1) mixing water, a dicarboxylic acid (e.g., oxalic acid) and a niobium compound (e.g., niobic acid) to form a pre-niobium-containing aqueous solution or a niobium-containing aqueous mixture containing part of the compound niobium in the form of a suspension; (2) cooling the pre-niobium-containing aqueous solution or niobium-containing aqueous mixture to precipitate a portion of the dicarboxylic acid; and (3) removing the precipitated dicarboxylic acid from the pre-niobium-containing aqueous solution or removing the precipitated dicarboxylic acid and suspension of the niobium compound from the niobium-containing aqueous mixture to form a niobium-containing aqueous liquid (B). Typically, aqueous liquids (B) obtained by this method are characterized by a dicarboxylic acid / niobium molar ratio in the range of about 2-4.

Especially suitable dicarboxylic acid is oxalic acid, and suitable niobium compounds for step (1) of this process include niobic acid, niobium acid oxalate and ammonium niobate oxalate. These niobium compounds can be used in solid form, as a mixture or dispersion in a suitable medium. When using niobium acid oxalate or ammonium niobate oxalate as the niobium compound, dicarboxylic acid may not be used. When using niobic acid as a niobium compound to remove acidic impurities that could contaminate niobic acid at the stage of its preparation, niobic acid can be washed with aqueous ammonia and / or water before use. In one embodiment, a freshly prepared niobium compound can be used as the niobium compound. However, in the above method, you can use the niobium compound, slightly losing its properties (for example, due to dehydration) as a result of long storage, etc. In step (1) of this method, the dissolution of the niobium compound can be accelerated by the addition of a small amount of aqueous ammonia or by heating.

The concentration of the niobium compound (in terms of niobium) in a preliminary niobium-containing aqueous solution or aqueous mixture can be maintained in the range of 0.2-0.8 mol / kg of solution or mixture. In one embodiment, dicarboxylic acid can be used in an amount such that the molar ratio of dicarboxylic acid to niobium compound based on niobium is about 3-6. When using an excess of dicarboxylic acid in an aqueous solution of dicarboxylic acid, a large amount of the niobium compound can be dissolved; however, an unfavorable circumstance arises when the amount of dicarboxylic acid that precipitates upon cooling of the obtained preliminary niobium-containing aqueous solution or mixture becomes so large that the possibility of using dicarboxylic acid is reduced. On the other hand, when using a non-optimal amount of dicarboxylic acid, an unfavorable circumstance arises because a large amount of niobium remains undissolved and suspended in an aqueous solution of dicarboxylic acid to form a mixture from which the suspended niobium compound is removed, which reduces the possibility of using the niobium compound.

In step (2), any cooling method may be used. For example, you can simply cool with an ice bath.

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

In the case where the dicarboxylic acid / niobium molar ratio in the resulting niobium-containing aqueous solution is outside the range of about 2-4, either the niobium compound or dicarboxylic acid can be added to the aqueous liquid (B) so that the dicarboxylic acid / niobium molar ratio in solution hit the specified interval. However, usually this operation is not needed, because an aqueous liquid (B) with a dicarboxylic acid / niobium molar ratio in the range of 2-4 can be prepared by adjusting the concentration of the niobium compound, the dicarboxylic acid / niobium ratio and the cooling temperature of the above pre-niobium-containing aqueous solution or aqueous mixture.

Aqueous liquid (B) can also be prepared from the following components. For example, at least a portion of an aqueous liquid (B) containing a niobium compound or a mixture of a niobium compound and a dicarboxylic acid is used together with hydrogen hydroxide. In this case, it is better that the molar ratio of hydrogen peroxide to the niobium compound (molar ratio of H ₂ O ₂ / Nb) calculated as niobium is in the range of 0.5-20 or 1-20.

In another example, at least a portion of the aqueous liquid (B) containing the niobium compound or dicarboxylic acid or a mixture of the niobium compound and dicarboxylic acid or a mixture thereof with hydrogen peroxide also includes an antimony compound (e.g., antimony (III) oxide), a titanium compound ( for example, titanium dioxide, which may be a mixture of rutile and anatase) and / or a cerium compound (e.g. cerium acetate). In this case, take such a quantity of hydrogen peroxide so that the molar ratio of hydrogen peroxide to the niobium compound (molar ratio of H ₂ O ₂ / Nb) calculated for niobium is in the range of 0.5-20 or 1-20. In another example, the amount of antimony compound mixed with at least a portion of the aqueous liquid (B) and hydrogen peroxide is taken such that the molar ratio (molar ratio Sb / Nb) of the antimony compound based on antimony and the niobium compound in terms of niobium is not more than 5 and was in the range of 0.01-2.

The aqueous mixture (A) and the aqueous liquid (B) are mixed in the desired ratio in accordance with the desired composition of the catalyst, which leads to an aqueous mixture of the ingredients, usually in suspension. The content of the ingredients in the aqueous mixture is usually in the range of up to about 50 wt.%, Or 70-95 wt.%, Or 75-90 wt.%.

Upon receipt of the supported on silica catalyst of the present invention, the initial aqueous mixture is prepared so that it contains a source of silicon oxide (namely, silica sol or fused silica). The amount of silica source can be approximately set in accordance with the amount of silica support in the fabricated catalyst.

Drying stage

To obtain a dry catalyst precursor, the aqueous mixture of ingredients is dried. Drying can be carried out by conventional methods, for example by spray drying or evaporation. Spray drying is particularly applicable, as the result is small spherical particles of a dry catalyst. Spray drying can be carried out by centrifugation, by blowing through a nozzle of a two-phase flow or by blowing through a nozzle at high pressure. As a heat source for drying, you can use air heated by water vapor, an electric heater, etc. In one embodiment, the temperature of the spray dryer at the entrance to the drying zone is 150-300 ° C.

Calcination stage

The dry catalyst precursor is converted to a mixed metal oxide catalyst by calcination. Calcination is carried out in a drum furnace, in a fluidized-bed furnace, in a fluidized-bed reactor, in a fixed-bed reactor, and the like. The calcination conditions are preselected so that the resulting catalyst has a specific surface area of from about 5 m ² / g to about 35 m ² / g, from about 15 m ² / g to about 20 m ² / g. During calcination, the dried catalyst precursor is heated to a final temperature in the range of about 600-680 ° C.

In the present invention, the calcination method comprises pre-continuously or periodically heating the dried catalyst precursor from a temperature below 200 ° C to a temperature not higher than about 400 ° C, not higher than about 350 ° C, not higher than about 300 ° C, at a rate of more than 15 ° C / min . In one embodiment, the pre-calcination temperature is 300 ° C. In this embodiment, the heating rate is about 20 ° C / min. In another embodiment, the heating rate is 25 ° C / min. In yet another embodiment, the heating rate is 30 ° C / min. In yet another embodiment, the dry catalyst precursor is placed in a hot calcining apparatus at a temperature of about 300 ° C or slightly higher so that the temperature of the precursor rapidly rises to about 300 ° C.

The heating rate from the pre-temperature to the final calcination temperature may be about 0.5 ° C / min, 1 ° C / min, 2 ° C / min or 5 ° C / min, or any speed in the range of 0.5-5 ° C / min. In one embodiment, the heating rate in the temperature range from about 300 ° C to the intermediate temperature is about 1 ° C / min, and from the intermediate temperature to the final temperature, the heating rate is greater than 15 ° C / min, or greater than or equal to 20 ° C / min, or greater than or equal to 25 ° C / min, or greater than or equal to 30 ° C / min. In another embodiment, the solid after reaching an intermediate temperature can be cooled and then heated to a final temperature at a heating rate greater than about 15 ° C / min or greater than or equal to 20 ° C / min or greater than or equal to 25 ° C / min or greater or equal to 30 ° C / min.

In one embodiment of the invention, the calcination is carried out in two stages: (1) to an intermediate or pre-temperature and (2) from an intermediate or pre-temperature to a final temperature. In one embodiment, the solid from the calcination step (1), optionally chilled, is placed in a hot oven at a temperature of about the final temperature so that the temperature of the precursor rises rapidly to the final temperature.

In one embodiment, the heating rate in the temperature range from about 300 ° C to 340-350 ° C, 345 ° C is about 0.5 ° C / min or 1 ° C / min or about 2 ° C / min or about 5 ° C / min or any speed in the range of 0.5-5 ° C / min. In one embodiment, the solid is maintained at a temperature in the range of 300-400 ° C, in the range of 340-350 ° C, at 345 ° C for about 1-4 hours. In one embodiment, the solid is heated at a rate of 2.45 ° C / min in the temperature range 345-680 ° C.

Upon reaching the final temperature, the solid can be maintained at this temperature for about 1-3 hours, about 2 hours. The final temperature can be 600 ° C, 610 ° C, 620 ° C, 630 ° C, 640 ° C, 650 ° C, 660 ° C, 670 ° C and 680 ° C or any temperature in the range of 600-680 ° C. In one embodiment, the solid is heated at a rate of 0.5 ° C / min in the range of about 600 ° C-680 ° C. In yet another embodiment, the solid is heated at a rate of 1 ° C / min in the range of about 600-680 ° C.

Calcination can be carried out in air or in a stream of air. However, at least a portion of the calcination is carried out in a gas atmosphere (for example, in a gas stream), such as nitrogen, substantially free of oxygen. The present invention contemplates the use of an inert gas. The inert gas may be a noble gas. The gas may contain nitrogen. The gas may be selected from air, water vapor, superheated steam, carbon monoxide and carbon dioxide. In one embodiment of the present invention, calcination can be carried out in a stream of nitrogen that is substantially oxygen free in both temperature ranges of step (1) to about 400-450 ° C and (2) above about 400-450 ° C. In another embodiment of the present invention, the calcination can be carried out in a stream of air in the temperature range of steps (1) to about 400-450 ° C in a stream of nitrogen that is practically free of oxygen, and in the temperature range of step (2) above about 400-450 ° C. The gas flow rate can be critical especially in the temperature range (1) to about 400-450 ° C. The gas flow rate may be in the range of about 0.67-2.5 cm ³ per g of catalyst precursor per minute.

In one embodiment, the catalyst precursor is calcined in a stream of nitrogen in a 1-foot vertical tube in two stages. After the temperature in the loaded 1-foot vertical tube rises at a heating rate of about 1.2 ° C / min to 345 ° C, the temperature is maintained at 345 ° C for 4 hours. In a second step, the temperature is raised at a rate of about 2.3 ° C / min to a temperature of 640 ° C. Calcination is completed after keeping at 640 ° C for 2 hours.

Tellurium Introduction

Tellurium can be introduced into the catalyst by adding a tellurium source either to the aqueous mixture (A), to the aqueous mixture (B), or to a 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 calcined catalyst prepared as described in this application with a solution of Te (OH) ₆ and water. This solution is added in terms of moisture capacity to the catalyst with stirring, which makes it possible to obtain a catalyst with the desired concentration of tellurium on the surface per mol of molybdenum. The catalyst is then dried, usually placed in a dryer at 90 ° C overnight in an atmosphere of air. The dried impregnated material is then heated, usually in nitrogen, at 450 ° C. for 2 hours.

The method of hydrothermal synthesis

In one embodiment, the catalyst compositions described herein can be prepared by hydrothermal synthesis methods. Methods of hydrothermal synthesis are disclosed in US patent application No. 2003/0004379, Gaffhey et al., Watanabe et al., “A New Method for the Synthesis of Mixed Oxide Catalysts Mo-V-Nb-Te Oxidative Ammonolysis of Propane”, Applied Catalysis A: General, 194- 195, pp. 479-485 (2000), and Ueda et al., “Selective oxidation of lower alkanes in the presence of hydrothermally synthesized Mo-VMO oxide catalysts (M = Al, Ga, Bi, Sb and Te)”, Applied Catalysis A: General, 200, pp. 135-145, which are incorporated herein by reference.

Typically, the catalyst compositions described herein can be prepared by hydrothermal synthesis. In this case, the starting compounds (i.e., compounds that serve as a source of one or more metals for the metal oxide catalyst composition) are mixed with an aqueous solution to form a reaction medium and allowed to interact in the reaction medium at elevated pressure and elevated temperature in a closed reaction vessel over time sufficient to form a mixed metal oxide. In one embodiment, hydrothermal synthesis is continued for a time sufficient for the reaction to complete with any organic compound in the reaction medium, for example, with the solvents used in the preparation of the catalysts, or with any organic compound introduced with any starting compound — a component of a mixed metal oxide catalyst composition . This option simplifies the handling and processing of the mixed metal oxide catalyst.

The starting compounds are reacted in a closed reaction vessel at a temperature above 100 ° C and at a pressure above atmospheric to form a mixed metal oxide precursor. In one embodiment, the starting compounds are reacted in a closed reaction vessel at a temperature of at least about 125 ° C, in another embodiment, at a temperature of at least about 150 ° C, and in another embodiment, at a temperature of at least about 175 ° C. In one embodiment, the starting compounds are reacted in a closed reaction vessel at a pressure of at least about 25 psi. inch and in another embodiment, at a pressure of at least about 50 psi. inch and in another embodiment, at a pressure of at least about 100 psi. inch. Such closed reaction vessels may be equipped with a pressure monitoring sensor to prevent overpressure in the vessel and / or to control the pressure of the reaction mixture.

In one or more embodiments, the starting compounds are introduced into the reaction by a method that involves mixing the starting compounds during the reaction. The specific mixing mechanism is not critical and may include mixing (for example, stirring or shaking) of the components during the reaction in any effective manner. Such methods include, for example, mixing the components of the reaction vessel by shaking, turning, or vibration. Such methods also include, for example, stirring with a stirrer located at least partially in the reaction vessel and driven by an engine coupled to the stirrer or reaction vessel to propel the stirrer and the reaction vessel. The working part of the mixer can be located directly on the shaft, or it is driven through the shaft. The motor can be connected to the mixer directly or indirectly (for example, through magnetic coupling). Typically, stirring is sufficient to mix the components and an effective reaction between the components of the reaction medium to form a more homogeneous reaction medium (for example, leading to a more homogeneous mixed metal oxide precursor) compared to the reaction without stirring. This leads to a more efficient absorption of the starting materials and a more uniform mixed metal oxide. Stirring the reaction medium during the reaction also leads to the formation of a mixed metal oxide in the solution, and not on the walls of the reaction vessel. This makes it possible to more easily isolate and separate the resulting mixed metal oxide by methods such as centrifugation, decantation or filtration, and to avoid the need to extract most of the product from the walls of the reaction vessel. Another advantage is that the presence of the mixed metal oxide in the solution allows the particles to grow along all faces, and not on the limited faces available in the case of particle growth on the walls of the reactor.

In general, it is desirable to maintain free space in the reaction vessel in its upper part. The volume of this space may depend on the design of the reactor or the type of mixing of the reaction mixture. Stirred reaction vessels, for example, can have 50% free space. Usually the free space is filled with air, which introduces a small amount of oxygen into the reaction. However, the free space can be filled with other gases, as is known to specialists in this field, or reagents of the type O ₂ , or even an inert gas of the type Ar or Ne. Those skilled in the art will understand that the amount of free space and the gas contained in it depend on the nature of the reaction.

The starting compounds can react in a closed reaction vessel at an initial pH of not higher than about 4. During hydrothermal synthesis, the pH of the reaction mixture can change and finally reach a value above or below the initial pH. In one or more embodiments, the starting compounds are reacted in a closed reaction vessel at a pH of not higher than about 3.5. In some embodiments, the components can be reacted in a closed reaction vessel at a pH of not higher than about 3.0 or not higher than about 2.5 or not higher than about 2.0, not higher than about 1.5 or not higher than about 1.0, not higher than about 0.5, or not higher than about 0. B in one or more embodiments, the pH is in the range of about 0-4, and in other embodiments, about 0.5-3.5. In some embodiments, the pH may be in the range of about 0.7-3.3 or about 1-3. You can adjust the pH by adding acid or base to the reaction mixture.

The starting compounds can be reacted in closed reaction vessels under the above conditions (including, for example, reaction temperature, reaction pressure, pH, stirring and the like, as described above) for a time sufficient to form a mixed metal oxide. In one or more embodiments, the mixed metal oxide is a solid solution containing the necessary elements, as described above, and in some embodiments, at least some of them are characterized by the necessary crystal structure for the active and selective catalytic oxidation and / or oxidative ammonolysis of propane or isobutane, as described below. The exact time is not strictly critical and may be, for example, about six hours, at least about twelve hours, at least about eighteen hours, at least about twenty four hours, at least about thirty hours, at least about thirty six hours, at least about forty two hours, at least about forty eight hours, at least about fifty four hours, at least about sixty hours, or at least about sixty six hours if at least about seventy-two hours. The reaction time may even be three days, including, for example, at least about four days, at least about five days, at least about six days, at least about seven days, at least about two weeks, or at least about three weeks, or at least about one month.

After the reaction step, methods for preparing the catalysts may include processing steps, including, for example, cooling the reaction medium containing the mixed metal oxide (e.g., to ordinary temperature), separating the solid particles of the mixed metal oxide from the liquid (e.g., by centrifuging and / or decanting the mother liquor solution or, alternatively, by filtration), washing the separated solid particles (e.g., with distilled or deionized water), a repeated separation step, a single or multiple washing, and effective final separation step. In one embodiment, the processing step includes drying the reaction mixture, for example, on a rotary evaporator by spray drying, freeze-drying, etc. This eliminates the formation of metal-containing wastewater.

After the processing steps, the separated and washed mixed metal oxide can be dried. Drying the mixed metal oxide can be effective under normal conditions (for example, at a temperature of about 25 ° C. and atmospheric pressure) and / or in a furnace. In one or more embodiments, the mixed metal oxide can be dried at a temperature in the range of about 40-150 ° C. and in one embodiment, about 120 ° C. for a period of about five to about fifteen hours, and in another embodiment, about twelve hours. The drying can be carried out effectively in a controlled or unregulated atmosphere, and the drying atmosphere can be an inert gas, an oxidizing gas, a reducing gas or air. In one or more embodiments, drying is carried out in air.

In the next cooking step, the dried mixed metal oxide can be treated to form a mixed metal oxide catalyst. Such processing may include calcining steps (for example, including heat treatment under oxidizing or reducing conditions) in an atmosphere of various gases. The obtained mixed metal oxide can be crushed or crushed prior to such treatment and / or at intervals during such pretreatment. In one or more embodiments, the dried mixed metal oxide may optionally be ground and then calcined to form a mixed metal oxide catalyst. Calcination can be carried out in an inert atmosphere, for example in nitrogen. In one or more embodiments, calcination conditions include temperatures in the range of about 400-700 ° C, in some embodiments, about 500-650 ° C, and in some embodiments, calcination can be at about 600 ° C.

The treated (e.g., calcined) mixed metal oxide can also be mechanically treated, for example, by grinding, sieving and pressing the mixed metal oxide to its final form for use in a fixed-bed reactor or in a fluidized-bed reactor. As is known to those skilled in the art, the catalyst can be milled in a variety of ways, including grinding in a vibratory mill, in a ball mill, and the like. Optimum grinding conditions can be selected depending on the size of the sample and the composition of the catalyst. In one embodiment, about 2 g of the non-supported catalyst can be ground in a ball mill for about 2-15 minutes.

In one or more embodiments, the catalyst can be molded to its final form prior to all calcining or other heat treatment operations. For example, when preparing a catalyst for a fixed bed, the suspension of the catalyst precursor is usually dried by heating at elevated temperature and then molded (for example, extruded, tableted, etc.) to the size and configuration of the catalyst particles in the fixed bed before calcining. Similarly, when preparing catalysts for a fluidized bed, a suspension of the catalyst precursor can be spray-dried to form microspherical catalyst particles with a diameter in the range of 10-200 μm and then calcined.

In the catalyst preparation methods described herein, starting compounds containing metal components used in various catalyst synthesis methods (also called “source” or “sources”) can be introduced into the reaction vessel in the form of aqueous solutions of metal salts. Some sources of metal components can be introduced into the reaction vessels as solids or suspensions containing solid particles dispersed in aqueous media. Some sources of metal components can be introduced into the reaction vessels in the form of solids or suspensions containing solid particles dispersed in non-aqueous solvents or other non-aqueous media.

Suitable sources for the synthesis of catalysts described herein include the following. A suitable source of molybdenum may include molybdenum (VI) oxide (MoO ₃ ), ammonium heptamolybdate or molybdenum acid. A suitable source of vanadium may include vanadyl sulfate, ammonium metavanadate or vanadium oxide (V). A suitable source of antimony may include antimony (III) oxide, antimony (III) acetate, antimony (III) oxalate, antimony (V) oxide, antimony (III) sulfate or antimony (III) tartrate. A suitable source of niobium may include niobium oxalate, ammonium oxalate niobate, niobium oxide, niobium ethoxide or niobic acid.

A suitable tellurium source may include telluric acid, tellurium dioxide, tellurium trioxide, or an organic tellurium compound such as methyltellurol and dimethyltellurol.

A suitable source of titanium may include titanium dioxide (TiO ₂ ) (rutile and / or anatase), for example, Degussa P-25, titanium isopropoxide, TiO (oxalate), TiO (acetylacetonate) ₂ or titanium alkoxide complexes, for example, Tyzor 131. Suitable the tin source may include tin (II) acetate. A suitable germanium source may include germanium (IV) oxide. A suitable source of zirconium may include zirconyl nitrate or zirconium (IV) oxide. A suitable hafnium source may include hafnium (IV) chloride or hafnium (IV) oxide.

Suitable sources of lanthanum may include lanthanum (III) chloride or lanthanum (III) oxide and lanthanum (III) acetate hydrate. Suitable cerium sources may include cerium (III) acetate hydrate. Suitable praseodymium sources may include praseodymium (III) chloride, praseodymium (III, IV) oxide or praseodymium (III) isopropoxide and praseodymium (III) acetate hydrate. Suitable sources of neodymium may include neodymium (III) chloride, neodymium (III) oxide or neodymium (III) isopropoxide and neodymium (III) acetate hydrate. Suitable sources of samarium may include samarium (III) chloride, samarium (III) oxide or samarium (III) isopropoxide and samarium (III) acetate hydrate. Suitable sources of europium 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, gadolinium (III) oxide and gadolinium (III) acetate hydrate. Suitable sources of terbium include terbium (III) chloride or terbium (III) oxide and terbium (III) acetate hydrate. Suitable sources of dysprosium 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 erbium sources may include erbium (III) chloride, erbium (III) oxide or erbium (III) isopropoxide and erbium (III) acetate hydrate. Suitable sources of thulium may include thulium (III) chloride or thulium (III) oxide and thulium (III) acetate hydrate. Suitable ytterbium sources may include ytterbium (III) chloride, ytterbium (III) oxide or ytterbium (III) acetate hydrate. Suitable sources of lutetium may include lutetium (III) chloride or lutetium (III) oxide and lutetium (III) acetate hydrate. As sources of the above metals, their nitrates can also be used.

Solvents that can be used to prepare the mixed metal oxides of this invention include, but are not limited to, water, alcohols such as methanol, ethanol, propanol, diols (e.g. ethylene glycol, propylene glycol, etc.), organic acids, such as acetic acid, as well as other polar solvents used in this field. In one or more embodiments, the metal sources are at least partially soluble in the solvent at least at the temperature and pressure of the reaction, and in some embodiments, the metal sources are slightly soluble in the solvent. In one or more embodiments, the solvent is water. Any water that is suitable for use in chemical synthesis may be used. Water may be, but not necessarily, distilled and / or deionized.

The amount of aqueous solvent in the reaction medium may vary due to the different solubility of the starting compounds, which are used to obtain a specific mixed metal oxide. The amount of aqueous solvent should be at least sufficient to form a suspension (mixture of solids and liquids that can be mixed) of the reagents. Typically, in the hydrothermal synthesis of mixed metal oxides, a certain amount of free space is left in the upper part of the reaction vessel.

Variations to these methods will be apparent to those skilled in the art. For example, a method of preparing the catalyst indicated herein of the following empirical formula:

M _O 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 ,

in which L is La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and mixtures thereof, “e” is greater than zero and less than about 0.02 and “n” is defined the degree of oxidation of other elements, includes the preparation of solutions or suspensions of the starting compounds for the catalyst. For one or the first suspension, molybdenum trioxide (MoO ₃ ), antimony oxide (Sb ₂ O ₃ ), telluric acid (Te (OH) ₆ ), titanium dioxide (TiO ₂ ) and at least one starting compound “L” are dissolved / suspended in water in the required proportions (all ratios are given based on metal molybdenum). In another or second solution or in a second solution or suspension, vanadyl sulfate (VOSO ₄ ) is dissolved / suspended in water. Alternatively, vanadyl sulfate can be added in solid form. In another or third solution or suspension, niobic acid (Nb ₂ O ₅ · nH ₂ O) is mixed with oxalic acid (HO ₂ CCO ₂ H). Various molar ratios of oxalic acid: niobium can be used. In one embodiment, the molar ratio of oxalic acid: niobium is about 3: 1. The three solutions / suspensions are combined together, heated with stirring to 175 ° C, kept at this temperature for 67 hours and then cooled to room temperature, usually by natural heat dissipation. The cooled suspension is filtered to remove the mother liquor, the remaining solid precipitate is washed, then dried and then calcined in a nitrogen atmosphere at 600 ° C to activate the catalyst. The calcined catalyst is crushed, then tableted and cut or spray dried for testing and / or direct use.

Conversion of propane and isobutane by oxidative ammonolysis and oxidation reactions

In one or more embodiments, propane is converted to acrylonitrile and / or isobutane to methacrylonitrile using one or more of the above catalysts in a gas-phase flow reactor by contacting the catalyst with propane or isobutane in the presence of oxygen (for example, in a reaction zone in a feed stream comprising an oxygen-containing gas , usually such as air) and ammonia under reaction conditions effective to form acrylonitrile or methacrylonitrile. In some embodiments, the feed stream contains propane or isobutane, an oxygen-containing gas such as air, and ammonia in the following molar ratios. In one or more embodiments, the molar ratio of propane or isobutane to oxygen is about 0.125-5, in other embodiments, about 0.25-4, and in some embodiments, about 0.5-3.5. In one or more embodiments, the molar ratio of propane or isobutane to ammonia is about 0.3-2.5, and in other embodiments, about 0.5-2.0. The feed stream may also contain one or more additional components, including the resulting acrylonitrile or methacrylonitrile (for example, from a recycle stream or from the early stages of a multi-stage reactor) and / or water vapor. For example, the feed stream may contain about 5-30 wt.% One or more additional components relative to the total mass of propane or isobutane in the feed stream. In one embodiment, the catalyst compositions described herein are used in the oxidative ammonolysis of propane to acrylonitrile in the recycle of the isolated but not reacted starting materials.

Propane can also be converted to acrylic acid, and isobutane to methacrylic acid in the presence of one or more of the above catalysts in a gas-phase flow reactor by contacting the catalyst with propane in the presence of oxygen (for example, fed to the reaction zone in a stream comprising an oxygen-containing gas, usually air ) under reaction conditions effective for the formation of acrylic acid. The feed stream for this reaction contains propane and an oxygen-containing gas, such as air, in a molar ratio of propane or isobutane to oxygen in the range of about 0.15-5 and preferably about 0.25-2. The feed stream may also contain one or more additional components, including the resulting acrylic acid or methacrylic acid (for example, from a recycle stream or from an early stage of a multi-stage reactor), and / or water vapor. For example, a feed stream may contain about 5-30 wt.% Based on the total weight of the feed stream or in moles per amount of propane or isobutane in the feed stream.

The specific design of a gas-phase flow reactor is not strictly critical. Therefore, the gas phase flow reactor may be a fixed bed reactor, a fluidized bed reactor, or another type of reactor. The reactor may be single or may be part of a multi-stage system of reactors. In one or more embodiments, the reactor comprises one or more inlets for supplying a stream of starting reagents to the reaction zone containing the mixed metal oxide catalyst, and an outlet for discharging reaction products and unreacted reagents.

The reaction conditions are adjusted in such a way as to ensure the efficient conversion of propane to acrylonitrile or acrylic acid or the conversion of isobutane to methacrylonitrile or methacrylic acid. Typically, reaction conditions include a temperature range of about 300-550 ° C, in one or more embodiments, about 325-500 ° C, in some embodiments, about 350-450 ° C, and in other embodiments, about 430-520 ° C. The pressure in the reaction zone can be adjusted in the range from about 0 ft / sq. Inch to about 200 ft / sq. Inch, in one or more embodiments, from about 0 ft / sq. Inch to about 100 ft / sq. Inch and in some embodiments from about 0 ft / sq. inch to about 50 ft / sq. inch.

Typically, the flow rate of a feed containing propane or isobutane through a reaction zone in a gas phase flow reactor can be controlled so that the mass hourly space velocity (WHSV) is in the range of about 0.02-5, in some embodiments, about 0.05-1, and in other embodiments, about 0.1-0.5, in each case, for example, in grams of propane or isobutane per gram of catalyst. In one or more embodiments, increased catalyst activity is observed when the WHSV is at least about 0.1, in other embodiments at least about 0.15, and in still other embodiments at least about 0.2.

The resulting acrylonitrile and / or acrylic acid and / or methacrylonitrile and / or methacrylic acid can be separated, if necessary, from other by-products and / or from unreacted reagents by methods known in the art.

In one or more embodiments of the present invention, at least about 57% acrylonitrile can be obtained in one pass (i.e., without recycling) in the oxidative ammonolysis of propane. In some embodiments of the present invention, at least about 59% acrylonitrile can be obtained in a single pass (i.e., without recycling) in the oxidative ammonolysis of propane. In other embodiments of the present invention, at least about 61% acrylonitrile can be obtained in one pass (i.e., without recycling) in the oxidative ammonolysis of propane. Exhaust gases from the reactor may also contain CO _x (carbon dioxide + carbon monoxide), hydrocyanic acid (HCN), acetonitrile or methyl cyanide (CH ₃ CN), unreacted oxygen (O ₂ ), ammonia (NH ₃ ), nitrogen (N ₂ ) , helium (He) and entrained small particles of the catalyst.

The catalyst compositions of the present invention advantageously differ from the tellurium-containing catalysts described in the literature, since the catalyst compositions of the present invention do not noticeably lose tellurium from the active phase prepared and tested under the conditions described above. For example, in one or more embodiments, no visible tellurium deposits are formed in the nitrogen in the calcination vessel or in the calcination furnace by calcining the catalyst composition of the present invention for about 2 hours in nitrogen at a temperature of about 600 ° C. The catalyst compositions of the present invention have increased stability compared to other tellurium-containing catalysts. Such increased stability leads to a lower decrease in catalytic activity during operation and also makes it possible to maintain high activity at a higher space velocity.

SPECIFIC OPTIONS

To illustrate the present invention, mixed metal oxide catalysts were prepared and then tested under different reaction conditions. The following compositions are nominal and contain all metals taken for the preparation of the catalyst. Since some metals may or may not be completely reacted during the preparation of the catalyst, the actual composition of the final catalyst may vary slightly from the nominal compositions given below.

Example # 1 - Mo ₁ V _0.3 Sb _0.175 Nb _0.06 Te _0.02 Ti _0.1 Nd _0.005 O _n

MoO ₃ (8.0 g), Sb ₂ O ₃ (1.418 g), TiO ₂ (0.444 g), Te (OH) ₆ (0.255 g), Nd (OAc) ₃ (2.78 ml) were loaded into a 125 ml Teflon test tube reactor 0.1 M solution) and water (10 ml). In this and in the following several examples, “(OAc) ₃ ” means an acetate hydrate of the named lanthanide. The mixture was stirred for about 5 minutes, after which VOSO ₄ (16.67 ml of a 1 M solution) and niobium oxalate (7.39 ml of a 0.451 M solution in which the molar ratio of oxalate to niobium was equal to about 3/1) were added. Then, water was added in such an amount as to fill the volume of the tube by about 80%. The reactor was closed with a Teflon stopper, inserted into a metal casing, placed in a furnace preheated to 175 ° C, and continuously rotated to effectively mix liquid and solid reagents. After 67 hours, the reactor was cooled and the Teflon tube was removed from the casing. The resulting suspension was stirred for 2 minutes, then vacuum-filtered through a glass porous filter and washed with three 200 ml portions of water. The wet substance was dried in air at 120 ° C for 12 hours. The resulting solid was crushed and calcined in an atmosphere of N ₂ for 2 hours at 600 ° C. The solid was then crushed, pressed, sieved to a particle size of 145-355 μm and tested for catalytic activity. The resulting substance had a nominal composition of Mo ₁ V _0.3 Sb _0.175 Nb _0.06 Te _0.02 Ti _0.1 Nd _0.005 O _n .

The substance was tested as a catalyst for the heterogeneous oxidative ammonolysis of propane to acrylonitrile. At 420 ° C, WHSV = 0.2 and the composition of the raw material C ₃ H ₈ / NH ₃ / O ₂ / He = ₁ /1.2/ ₃ /12, the yield of acrylonitrile was 61% (propane conversion 89%, selectivity for acrylonitrile 68%).

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

The first sample was prepared as follows. MoO ₃ (1.152 g), VOSO ₄ (2.30 ml of 1.04 M solution), niobium oxalate (1.60 ml of 0.40 M solution in which the molar ratio of oxalate to niobium is approximately 3/1), Sb ₂ O were loaded into a 23 ml Teflon tube ₃ (2.93 ml 0.49 M suspension), TiO ₂ (2.85 ml 0.28 M suspension), Li (OAc) (1.00 ml 0.40 M solution), Te (OH) ₆ (0.80 ml 0.20 M solution) and Nd (OAc) ₃ ( 1.00 ml of a 0.04 M solution). Water was added so as to fill the volume of the tube by about 60%. Then the reactor was closed with a Teflon stopper, a metal casing, placed in a furnace preheated to 175 ° C, and continuously rotated to effectively mix liquid and solid reagents. After 48 hours, the reactor was cooled and a teflon tube was removed from the casing. The resulting suspension was stirred for 2 minutes, then was suction filtered through a glass porous filter and washed with three 150 ml portions of water. The wet substance was dried in air at 90 ° C for 12 hours. The resulting solid was crushed and calcined in an atmosphere of N ₂ for 2 hours at 600 ° C. This substance had a nominal composition of 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 substance was prepared as described above for the first material, except that lithium acetate was not used. This second substance had a nominal composition of Mo ₁ V _0.3 Sb _0.18 Nb _0.08 Te _0.02 Ti _0.1 Nd _0.005 O _n .

Portions of 0.45 g of the first substance and 0.94 g of the second substance were combined to form a sample with a nominal composition of 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 . The solid was crushed, pressed, sieved to a particle size of 145-355 μm and tested for catalytic activity.

The substance was tested as a catalyst for the heterogeneous oxidative ammonolysis of propane to acrylonitrile. At 433 ° C, WHSV = 0.2, and the composition of the raw materials C ₃ H ₈ / NH ₃ / O ₂ / N ₂ - 1 / 2.0 / 3/12 yielded an acrylonitrile yield of 60% (propane conversion 91%, selectivity for acrylonitrile 65% )

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 were loaded into a 125 ml Teflon tube. The mixture was stirred for about 5 minutes, after which VOSO ₄ (16.67 ml of a 1 M solution) and niobium oxalate (7.612 ml of a 0.438 M solution in which the molar ratio of oxalate to niobium was approximately 3/1) were added. Water was added so as to fill the reactor volume by about 80%. Then the reactor was closed with a Teflon stopper, a metal casing, placed in a furnace preheated to 175 ° C, and continuously rotated to effectively mix liquid and solid reagents. After 48 hours, the reactor was cooled and a teflon tube was removed from the casing. The resulting suspension was stirred for 2 minutes, separated by vacuum filtration through a glass porous filter and washed with three 200 ml portions of water. The wet substance was dried in air at 120 ° C for 12 hours. The resulting solid was crushed and calcined in an atmosphere of N ₂ for 2 hours at 600 ° C. The solid was crushed, pressed, sieved with a particle size of 145-355 μm and tested for catalytic activity. The resulting substance had a nominal composition of Mo ₁ V _0.3 Sb _0.2 Nb _0.06 Ti _0.1 Nd _0.005 O _n .

The substance was tested as a catalyst for the heterogeneous oxidative ammonolysis of propane to acrylonitrile. At 430 ° C, WHSV = 0.15 and the composition of the raw materials C ₃ Hs / NH ₃ / O ₂ / He = ₁ /1.2/ ₃ /12, the yield of acrylonitrile was 56% (propane conversion 87%, selectivity for acrylonitrile 64%).

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 tube. The mixture was stirred for about 5 minutes, after which VOSO ₄ (13.2 ml of a 1 M solution) and niobium oxalate (6.083 ml of a 0.434 M solution) were added. Water was added so as to fill the volume of the tube by about 80%. Then the reactor was closed with a Teflon stopper, a metal casing, placed in a furnace preheated to 175 ° C, and continuously rotated to effectively mix liquid and solid reagents. After 48 hours, the reactor was cooled and a teflon tube was removed from the casing. The resulting suspension was centrifuged to separate the solid reaction products from the liquid. The liquid was decanted and distilled water (25 ml) was added to the solid. The solid was ground and mixed to dissolve the soluble salts. The mixture was centrifuged and the liquid separated by decantation. This washing was carried out twice. The wet solid was dried in air at 120 ° C for 12 hours. The resulting solid was crushed and calcined in an atmosphere of N ₂ for 2 hours at 600 ° C. The solid was crushed, pressed, sieved with a particle size of 145-355 μm and tested for catalytic activity. The resulting substance had a nominal composition of Mo ₁ V _0.38 Sb _0.25 Nb _0.075 Ti _0.125 Nd _0.0062 O _n .

The substance was tested as a catalyst for the heterogeneous oxidative ammonolysis of propane to acrylonitrile. At 420 ° C, WHSV = 0.15 and the composition of the raw materials C ₃ H ₈ / NH ₃ / O ₂ / He = ₁ /1.2/ ₃ /12, a yield of acrylonitrile of 58% was obtained with a propane conversion of 84% and a selectivity for acrylonitrile of 69%.

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 tube. The mixture was stirred for about 5 minutes, after which VOSO ₄ (2.50 ml of a 1.0 M solution), TiO ₂ (0.833 ml of 0.08 g / ml suspension), Nd (OAc) ₃ (0.417 ml of a 0.1 M solution) and niobium oxalate (1.142 ml 0.438) were added. M solution). Water was added so as to fill the volume of the tube by about 80%. Then the reactor was closed with a Teflon stopper, a metal casing, placed in a furnace preheated to 175 ° C, and continuously rotated to effectively mix liquid and solid reagents. After 48 hours, the reactor was cooled and a teflon tube was removed from the casing. The resulting suspension was centrifuged to separate the solid reaction products from the liquid. The liquid was decanted and distilled water (5 ml) was added to the solid residue. The solid was ground and mixed to dissolve the soluble salts. The mixture was centrifuged and the liquid decanted. This washing was carried out twice. The wet solid was dried in air at 120 ° C for 12 hours. The resulting solid was then crushed and calcined in an atmosphere of N ₂ for 2 hours at 600 ° C. The solid was then crushed, compressed, sieved to select particles in the range of 145-355 μm and tested for catalytic activity. This substance had a nominal composition of Mo ₁ V _0.3 Sb _0.2 Nb _0.06 Ti _0.1 Ge _0.05 Nd _0.005 O _n .

The substance was tested as a catalyst for the heterogeneous oxidative ammonolysis of propane to acrylonitrile. At 420 ° C, WHSV = 0.15 and the composition of the raw material C ₃ H ₈ / NH ₃ / O ₂ / He = ₁ /1.2/ ₃ /12, a yield of acrylonitrile of 58% was obtained with a conversion of propane of 84% and a selectivity for acrylonitrile of 69%.

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 the “4-component base”) was prepared by the non-hydrothermal method and the calcination method described here. Similarly, for Example # 7, a catalyst of the formula MoV _0.21 Sb _0.24 Te _0.04 Nb _0.09 O _x / 45% SiO _{2 was} prepared by additionally introducing tellurium into the “4-component base” by the impregnation method described here.

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

For comparative example # 8, a base catalyst of the formula MoV _0.3 Sb _0.2 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂ (hereinafter referred to as “the 6-component base”) was prepared by the non-hydrothermal method and the calcination method described here. Similarly, for comparative example # 9 and examples # 10- # 12, the following catalytic compositions were prepared with different tellurium contents by additionally introducing tellurium into the “6 component base” by the impregnation method described herein.

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: 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- # 12 were tested in a 40 cm ³ 1-inch diameter fluidized bed laboratory reactor. About 20-45 g of catalyst particles or catalyst mixtures were charged into the reactor. Propane was fed into the reactor at a rate of about 0.04-0.15 WHSV. The pressure in the reactor was maintained at about 2-15 psi. inch. The temperature in the reactor was set in the range of about 420-460 ° C. Typically, ammonia was fed into the reactor at such a rate that the ratio of ammonia to propane was about 1-1.5. Oxygen was introduced into the reactor at such a rate that the ratio of oxygen to propane was approximately 3.4. Nitrogen was fed into the reactor at such a rate that the ratio of nitrogen to propane was approximately 12.6. The test results of the catalysts from comparative examples # 6 and # 8 and examples # 7 and # 9- # 12 are summarized in Table 1 below.

Table 1 Example No. Catalyst composition Temp. ° C TIS h Con ₃ ,% AN select,% AN output,% Whsv Wed 6 MoV _0.21 Sb _0.24 Nb _0.09 O _x / 45% SiO ₂ 440 27 82.3 41.2 33.9 0.05 440 48 75.1 43.4 32.6 0.07 7 MoV _0.21 Sb _0.24 Te _0.04 Nb _0.09 O _x / 45% SiO ₂ 440 65 78.8 51.2 40.3 0.049 450 218 80.6 53.8 43.4 0.07 Wed 8 MoV _0.3 Sb _0.2 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂ 440 66 82 41.4 34.0 0.05 Wed 9 MoV _0.3 Sb _0.2 Te _0.06 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂ 440 21 58.1 34.5 20.0 0.05 10 MoV _0.3 Sb _0.2 Te _0.04 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂ 440 138 81.7 48.9 40.0 0.05 455 332 78.3 48.3 37.8 0.07 eleven MoV _0.3 Sb _0.2 Te _0.03 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂ 440 23.3 73.6 46.6 34.3 0.049 440 45 65.4 49.9 32.6 0.069 12 MoV _0.3 Sb _0.2 Te _0.02 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂ 440 67 79.2 41.3 32.7 0.05

Comparative Example # 13 and Examples # 14 and # 15

For comparative example # 13, a 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 as} described herein by the non-hydrothermal and calcination methods was prepared. Similarly, for examples # 14 and # 15, the following catalyst compositions were prepared with different tellurium contents by additionally introducing tellurium into the catalyst by the impregnation method described herein.

Example # 14: MoV _0.25 Sb _0.167 Te _0.02 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂

Example # 15: MoV _0.25 Sb _0.167 Te _0.04 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂

Antimony (0.08 mol Sb / mol Mo) was additionally added to the catalysts of comparative example # 13 and examples # 14 and # 15 by spraying Sb ₂ O ₃ on the catalyst. The catalysts were tested in a 40 cm ³ laboratory fluidized bed reactor under the same conditions as described above for comparative examples # 6 and # 8 and examples # 7 and # 9- # 12. The test results of the catalysts of comparative example # 13 and examples # 14 and # 15 are summarized in Table 2 below:

table 2 Example No. Catalyst composition Temp. ° C TIS h Con ₃ ,% AN select,% AN output,% Whsv Wed 13 MoV _0.25 Sb _0.167 Nb _0.08 Nd _0.002 Ce _0.003 Li _0.013 O _x / 45% SiO ₂ 440 16 67.3 54.7 36.8 0.060 fourteen MoV _0.25 Sb _0.167 Te _0.02 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂ 440 16 70.6 58.3 41.2 0.060 fifteen MoV _0.25 Sb _0.167 Te _0.04 Nb _0.08 Ti _0.1 Ce _0.005 O _x / 45% SiO ₂ 439 16 79.6 57.2 45.5 0.060 439 twenty 82.6 55.6 45.9 0.055 439 92 83.9 57.0 47.8 0.055 439 113 86.3 55.3 47.8 0.050 442 117 87.9 54.6 48.0 0.050 443 119 88.1 53.6 47.2 0.055 445 135 88.4 54.1 47.9 0.055 447 140 89.6 53.4 47.8 0.055 446 142 87.6 55.5 48.7 0.055

In this application and above in tables 1 and 2, "Temp" is the temperature of the reactor in degrees Celsius. “TIS” means “hours of operation” in hours (h). "Con ₃ " means the conversion of propane to mol. percent for one pass of propane to all major and by-products. "AN sat" means the selectivity for the formation of acrylonitrile, which is equal to the percentage of moles of obtained acrylonitrile to moles of converted propane. "AN yield" means the yield of acrylonitrile in mole percent for one pass of propane to acrylonitrile. “WHSV” means the mass hourly space velocity of propane fed to the reactor, expressed as propane mass / catalyst mass / hour, also known as “wwh”.

Although the above description and these options are typical for the practice of the present invention, it is obvious that in the light of this description, specialists in this field can offer many alternatives, modifications and variations. Accordingly, it is assumed that all such alternatives, modifications and variations are within the scope of the attached formula and correspond to its spirit.

Claims (33)

1. The method of oxidative ammonolysis of a saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons to produce an unsaturated nitrile, comprising contacting a saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons with ammonia and an oxygen-containing gas in the presence of a catalytic composition containing a mixed empirical formula:
Mo ₁ V _a Sb _b Nb _c Te _d X _e L _f O _n ,
where 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 <0.6,
0 <f <0.1; and
n represents the number of oxygen atoms necessary to saturate the valency of all other elements in the mixed oxide, provided that one or more other elements in the mixed oxide can be present in a lower oxidation state than their higher oxidation state, and where a, b, c , d, e and f is the ratio of the number of moles of the corresponding element to the number of moles of Mo. 2. The method according to claim 1, in which the catalytic composition has a composition where 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 0.001 <f < 0.05. 3. The method according to claim 1, in which X is selected from the group consisting of elements Ti, Sn and mixtures thereof. 4. The method according to claim 1, in which L is selected from the group consisting of elements Nd, Ce, Pr and mixtures thereof. 5. The method according to claim 1, in which the catalytic composition includes a carrier that is selected from the group consisting of silica, alumina, zirconia, titanium oxide, or mixtures thereof. 6. The method according to claim 5, in which on the carrier is approximately 10-70 wt.% The catalyst. 7. The method according to claim 1, in which the hydrocarbon comprises propane, isobutane or a mixture thereof. 8. The method according to claim 1, in which a stream of raw materials containing a saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons, ammonia and an oxygen-containing gas is supplied, wherein the molar ratio of hydrocarbon to oxygen is about 0.125-5. 9. The method according to claim 1, which includes supplying a feed stream containing a saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons, ammonia and an oxygen-containing gas, wherein the molar ratio of hydrocarbon to ammonia is about 0.3-2.5. 10. The method according to claim 1, in which a stream of raw materials containing a saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons is fed at a rate that is controlled to obtain a mass hourly space velocity of at least about 0.1 g of hydrocarbon per gram of catalyst. 11. The method according to claim 1, in which a stream of raw materials containing a saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons is fed at a rate that is adjusted to obtain a mass hourly space velocity of at least about 0.15 g of hydrocarbon per gram of catalyst. 12. The method according to claim 1, wherein a stream of feed containing saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons is fed at a rate that is controlled to produce a mass hourly space velocity of at least about 0.2 g of hydrocarbon per gram of catalyst. 13. A method of oxidative ammonolysis of a saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons to produce an unsaturated nitrile, comprising contacting a saturated or unsaturated hydrocarbon or a mixture of saturated or unsaturated hydrocarbons with ammonia and an oxygen-containing gas in the presence of a catalytic composition containing a mixed empirical formula:
MO ₁ V _a Sb _b Nb _c Te _d X _e L _f AgLi _h O _n ,
where 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; And selected from Na, K, Cs, Rb and mixtures thereof; 0.1 <a <0.8, 0.01 <b <0.6, 0.001 <s <0.3, 0.001 <d <0.06,
0 <e <0.6,
0 <f <0.1,
0 <g <0.1,
0 <h <0.1, and
n represents the number of oxygen atoms needed to saturate the valency of all other elements in the mixed oxide, provided that one or more other elements in the mixed oxide can be present in a lower oxidation state than their higher oxidation state, and where a, b, c, d, e, f, g and h are the ratio of the number of moles of the corresponding elements to the number of moles of Mo. 14. The method according to item 13, in which the catalytic composition has a composition where 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 0.001 <f < 0.05. 15. The method according to item 13, in which in the catalytic composition: 0.03 <h <0.06. 16. The method according to item 13, in which X is selected from the group consisting of elements Ti, Sn and mixtures thereof. 17. The method according to item 13, in which L is selected from the group consisting of elements Nd, Ce, Pr and mixtures thereof. 18. The method according to item 13, in which the catalytic composition includes a carrier that is selected from the group consisting of silicon oxide, alumina, zirconium oxide, titanium oxide or mixtures thereof. 19. The method according to p, in which the carrier contains about 10-70 wt.% The catalyst. 20. The method according to claim 1, in which the catalytic composition has a composition where 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. 21. The method according to claim 1, in which the catalytic composition has a composition where 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. 22. The method according to claim 1, in which the catalytic composition has a composition where 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. 23. The method according to item 13, in which the catalytic composition has a composition where 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. 24. The method according to item 13, in which the catalytic composition has a composition where 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. 25. The method according to item 13, in which the catalytic composition has a composition where 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.