RU2495024C2 - Method for oxidative ammonolysis or oxidation of propane and isobutane - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to a method for oxidative ammonolysis of a saturated hydrocarbon to obtain an unsaturated nitrile. The method involves preparing a catalytic mixture containing freshly prepared mixed metal oxide catalyst, a spent mixed metal oxide catalyst and an activity modifier, and contacting the saturated hydrocarbon with an oxygen-containing gas and ammonia in the presence of the catalytic mixture. The freshly prepared and spent mixed metal oxide catalysts contain molybdneum, vanadium, niobium and at least one element selected from antimony and tellurium, and optionally contain at least one element selected from lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, tungsten, titanium, tin, germanium, zirconium, lithium and hafnium. The catalysts can optionally contain a support selected from oxides of silicon, aluminium, zirconium, titanium or mixtures thereof. The activity modifier is selected from antimony (III) oxide, antimony (III) oxalate, antimony (III) tartrate, antimony (V) oxide, antimony tetroxide, SbOand mixtures thereof. The invention also relates to a method for oxidative ammonolysis, which involves mechanical mixing of a dry mixed metal oxide catalyst and an activity modifier to form a catalytic mixture and contacting a saturated hydrocarbon with an oxygen-containing gas and ammonia in the presence of said mixture.EFFECT: disclosed methods increase output of the end product.13 cl, 3 tbl, 4 ex

Description

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).

State of the 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). There are many patents and patent applications in the art, including, for example, US Pat. No. 5,750,760, Ushikubo et al., US Pat. No. 6,063,680, Komada et al., US Pat. No. 6,043,186, Komada et al., US Patent No. 6143916, Hinago and others, US patent No. 6514902, Inoue and others, US patent application No. 2004/0088118 A1, Komada and others, US patent application No. 2004/0063990 A1, Gaffhey and others and PCT patent application No. WO 2004/108278 A1, Asahi Kasei Kabushiki Kaisha.

Oxide promoters, such as niobium, tellurium and antimony oxides, were added to the mixed metal oxide Mo-V-O catalysts for propane oxidation by impregnation of moisture isotopes with metal isopropoxide solutions. The impregnation catalysts were then dried and calcined.

The surface of the mixed metal oxide catalysts was modified by tellurium vapor deposition and, as a result, a catalyst with increased activity was obtained. After modification, an additional improvement was carried out by treatment with oxygen.

To complex catalysts containing molybdenum, tellurium, vanadium and niobium, tellurium compounds and optionally molybdenum were added as activators. To maintain catalytic activity, after some time, a catalyst activator was added to the reactor.

The tellurium and / or molybdenum compound was added as a compensating compound to the used compound containing molybdenum, vanadium, niobium and antimony. In general, it was customary to add a molybdenum compound to a reactor with a molybdenum containing catalyst.

Successes have been achieved in this area by developing catalysts based on molybdenum, vanadium, antimony and other components effective in the conversion of propane to acrylonitrile and isobutane to methacrylonitrile (by oxidative ammonolysis) and / or the conversion of propane to acrylic acid and isobutane to methacrylic acid (by oxidation). However, the catalysts proposed for industrial use need further improvement. In General, known in the art, the catalytic systems of these reactions provide a low yield of the target product.

We need methods that provide a higher yield of the target product. It is also desirable to have catalysts with increased stability under reaction conditions and / or increased resistance to temperature fluctuations in the reactor.

SUMMARY OF THE INVENTION

In one embodiment, the present invention provides a process for the oxidative ammonolysis or oxidation of a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons to produce an unsaturated nitrile or unsaturated organic acid, said method comprising: preparing a mixture of catalysts comprising: a freshly prepared mixed metal oxide catalyst comprising molybdenum, vanadium, niobium and at least one element selected from the group consisting of antimony and tellurium; a spent mixed metal oxide catalyst comprising molybdenum, vanadium, niobium and at least one element selected from the group consisting of antimony and tellurium; activity modifier selected from the group consisting of aluminum compounds, antimony compounds, arsenic compounds, boron compounds, cerium compounds, germanium compounds, lithium compounds, molybdenum compounds, neodymium compounds, niobium compounds, phosphorus compounds, selenium compounds, tantalum compounds, tellurium compounds titanium compounds, tungsten compounds, vanadium compounds, zirconium compounds and mixtures thereof; and contacting a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons with an oxygen-containing gas or an oxygen-containing gas and ammonia in the presence of said catalytic mixture. In some embodiments, the catalyst mixture contains two or more activity modifiers.

The present invention also includes a method of oxidative ammonolysis of a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons to produce an unsaturated nitrile, said method comprising preparing a catalytic mixture containing an activity modifier selected from the group consisting of aluminum compounds, antimony compounds, arsenic compounds, boron compounds, cerium compounds, germanium compounds, lithium compounds, neodymium compounds, niobium compounds, phospho compounds and selenium compounds, tantalum compounds, tellurium compounds, titanium compounds, tungsten compounds, vanadium compounds, zirconium compounds and mixtures thereof; a freshly prepared mixed metal oxide catalyst and a spent mixed metal oxide catalyst; moreover, the composition of each of the specified freshly prepared and specified spent catalyst is determined independently by the empirical formula:

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

where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li and mixtures thereof; L is selected from the group consisting of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; 0.1≤ a ≤1.0, 0.01≤b≤1.0, 0.001≤c≤0.25, 0≤d≤0.6, 0≤e≤1; n is the number of oxygen atoms necessary to saturate the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a , b, c, d and e is the ratio of the number of moles of the corresponding elements to the number of moles of Mo; and 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 catalytic mixture.

In one embodiment, the invention provides a method for the oxidative ammonolysis or oxidation of a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons to produce an unsaturated nitrile or unsaturated organic acid, said method comprising preparing a catalytic mixture comprising a mechanical mixture of a mixed metal oxide catalyst and an activity modifier, the mixed metal oxide the catalyst includes molybdenum, vanadium, niobium and at least one element t selected from the group consisting of antimony and tellurium, and in which the activity modifier is selected from the group consisting of aluminum compounds, antimony compounds, arsenic compounds, boron compounds, cerium compounds, germanium compounds, lithium compounds, neodymium compounds, niobium compounds, phosphorus compounds, selenium compounds, tantalum compounds, tellurium compounds, titanium compounds, tungsten compounds, vanadium compounds, zirconium compounds and mixtures thereof; and contacting a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons with an oxygen-containing gas or an oxygen-containing gas and ammonia in the presence of a catalytic mixture.

The present invention also includes a process for the oxidative ammonolysis or oxidation of a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons to produce an unsaturated nitrile or unsaturated organic acid, said method comprising: combining a catalyst composition and an activity modifier to form a catalyst mixture, the catalyst composition comprising a mixed oxide defined by the empirical formula:

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

where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li and mixtures thereof; L is selected from the group consisting of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; 0.1≤ a ≤1.0, 0.01≤b≤1.0, 0.001≤c≤0.25, 0≤d≤0.6, 0≤e≤1; n is the number of oxygen atoms necessary for saturation, the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a , b, c, d and e is the ratio of the number of moles of the corresponding elements to the number of moles of Mo; and wherein the activity modifier is selected from the group consisting of aluminum compounds, antimony compounds, arsenic compounds, boron compounds, cerium compounds, germanium compounds, lithium compounds, neodymium compounds, niobium compounds, phosphorus compounds, selenium compounds, tantalum compounds, tellurium compounds, titanium compounds, tungsten compounds, vanadium compounds, zirconium compounds and mixtures thereof; and contacting a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons with an oxygen-containing gas or an oxygen-containing gas and ammonia in the presence of a catalytic mixture.

In one embodiment, the present invention relates to a method for the oxidative ammonolysis of a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons to produce an unsaturated nitrile, said method comprising: combining said catalyst composition and an activity modifier to form a catalyst mixture, the catalyst composition comprising a mixed oxide, as determined empirical formula:

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

where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li and mixtures thereof; L is selected from the group consisting of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; 0.1≤ a ≤1.0, 0.01≤b≤1.0, 0.001≤c≤0.25, 0≤d≤0.6, 0≤e≤1; n is the number of oxygen atoms necessary to saturate the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a , b, c, d and e is the ratio of the number of moles of the corresponding elements to the number of moles of Mo; and in which the activity modifier is selected from the group consisting of aluminum compounds, antimony compounds, arsenic compounds, boron compounds, cerium compounds, germanium compounds, lithium compounds, neodymium compounds, niobium compounds, phosphorus compounds, selenium compounds, tantalum compounds, tellurium compounds, titanium compounds, tungsten compounds, vanadium compounds, zirconium compounds and mixtures thereof; and 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 catalytic mixture.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention generally relates to a method for oxidative ammonolysis of a saturated or unsaturated hydrocarbon and to catalytic compositions that 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 reaction).

In one or more embodiments, unsaturated nitrile is prepared by a process comprising oxidative ammonolysis of a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons and comprising the steps of combining an activity modifier, a freshly prepared mixed metal oxide catalyst and a spent mixed metal oxide catalyst to form a catalytic mixture, and contacting the hydrocarbon with ammonia and oxygen-containing gas in the presence of this catalytic mixture.

The present invention provides a method for the oxidative ammonolysis or oxidation of a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons to produce an unsaturated nitrile or unsaturated organic acid, said method comprising: preparing a catalytic mixture containing a freshly prepared mixed metal oxide catalyst comprising molybdenum, vanadium, niobium and at least one element selected from the group consisting of antimony and tellurium, spent mixed an metal oxide catalyst comprising molybdenum, vanadium, niobium and at least one element selected from the group consisting of antimony and tellurium, and an activity modifier selected from the group consisting of aluminum compounds, antimony compounds, arsenic compounds, boron compound, cerium compounds , germanium compounds, lithium compounds, neodymium compounds, niobium compounds, phosphorus compounds, selenium compounds, tantalum compounds, tellurium compounds, titanium compounds, tungsten compounds, vanadium compounds, zirconium compounds and mixtures thereof; and contacting a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons with an oxygen-containing gas or an oxygen-containing gas and ammonia in the presence of this catalytic mixture.

In one embodiment, the catalyst modifier is selected from the group consisting of aluminum nitrate, aluminum oxide, antimony (III) oxide, antimony (III) oxalate, antimony (III) tartrate, antimony (V) oxide, antimony tetroxide, Sb ₆ O ₁₃ , oxide arsenic (III), arsenic (V) oxide, arsenic acid, boron oxide, boric acid, cerium-ammonium nitrate, cerium acetate, cerium (III) oxalate hydrate, cerium (IV) oxide, germanium (IV) oxide, lithium oxide, lithium hydroxide, lithium acetate, lithium nitrate, lithium tartrate, ammonium niobium oxalate, niobium oxalate, niobium oxide, fo pentoxide sphora, ammonium phosphate, selenium dioxide, tantalum (V) oxide, telluric acid, tellurium dioxide, tellurium dioxide, titanium-rutile dioxide (TiO ₂ ), titanium dioxide anatase (TiO ₂ ), titanium isopropoxide, TiO (oxalate), tungsten trioxide , vanadyl oxalate, vanadium (III) oxide, vanadium (IV) oxide, vanadium (V) oxide, zirconyl nitrate, zirconium oxide and mixtures thereof.

In yet another embodiment, the catalytic mixture contains at least about 0.01 mol of activity modifier per mole of Mo in the whole freshly prepared or spent mixed metal oxide catalyst. In another embodiment, the present invention comprises combining a freshly prepared mixed oxide catalyst with a wet impregnation activity modifier. In one aspect of the present invention, one or both of the freshly prepared mixed oxide catalysts and the spent mixed oxide catalyst are prepared by a non-hydrothermal synthesis process. In addition, the present invention may include mechanically mixing a freshly prepared mixed oxide catalyst, a spent mixed oxide catalyst, and an activity modifier; wherein said preparation step also includes the step of pre-mixing the freshly prepared mixed oxide catalyst composition and activity modifier. In addition, the present invention may include the step of heating or calcining said catalyst mixture.

In one embodiment, a freshly prepared catalyst composition comprises a mixed oxide defined by the empirical formula:

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

where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li and mixtures thereof; L is selected from the group consisting of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; 0.1≤ a ≤1.0, 0.01≤b≤1.0, 0.001≤c≤0.25, 0≤d≤0.6, 0≤e≤1; n is the number of oxygen atoms necessary to saturate the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a , b, c, d and e is the ratio of the number of moles of the corresponding elements to the number of moles of Mo.

In one embodiment, the catalyst composition used includes a mixed oxide defined by the empirical formula:

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

where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li and mixtures thereof; L is selected from the group consisting of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, But, Er, Tm, Yb, Lu, and mixtures thereof; 0.1≤ a ≤1.0, 0.01≤b≤1.0, 0.001≤c≤0.25, 0≤d≤0.6, 0≤e≤1; n is the number of oxygen atoms necessary to saturate the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a , b, c, d and e is the ratio of the number of moles of the corresponding elements to the number of moles of Mo.

The present invention also includes a process for the oxidative ammonolysis or oxidation of a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons to produce an unsaturated nitrile or unsaturated organic acid, said method comprising: mechanically mixing a dry mixed metal oxide catalyst and an activity modifier to form a catalytic mixture, the mixed metal oxide the catalyst includes molybdenum, vanadium, niobium and at least one element, in selected from the group consisting of antimony and tellurium, and the activity modifier is selected from the group consisting of aluminum compounds, antimony compounds, arsenic compounds, boron compounds, cerium compounds, germanium compounds, lithium compounds, neodymium compounds, niobium compounds, phosphorus compounds, compounds selenium, tantalum compounds, tellurium compounds, titanium compounds, tungsten compounds, vanadium compounds, zirconium compounds and mixtures thereof; and contacting a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons with an oxygen-containing gas or an oxygen-containing gas and ammonia in the presence of a catalytic mixture.

The activity modifier according to this invention is selected from the group consisting of aluminum nitrate, aluminum oxide, antimony (III) oxide, antimony (III) oxalate, antimony (III) tartrate, antimony (V) oxide, antimony tetroxide, Sb ₆ O ₁₃ , oxide arsenic (III), arsenic (V) oxide, arsenic acid, boron oxide, boric acid, cerium-ammonium nitrate, cerium acetate, cerium (III) oxalate hydrate, cerium (IV) oxide, germanium (IV) oxide, lithium oxide, lithium hydroxide, lithium acetate, lithium nitrate, lithium tartrate, ammonium niobium oxalate, niobium oxalate, niobium oxide, ne toksida phosphorus, ammonium phosphate, selenium dioxide, tantalum oxide (V), telluric acid, tellurium dioxide, trioxide, tellurium, titanium dioxide (TiO ₂₎ of rutile titanium dioxide (TiO _2), anatase titanium isopropoxide, TiO (oxalate), tungsten trioxide , vanadyl oxalate, vanadium (III) oxide, vanadium (IV) oxide, vanadium (V) oxide, zirconyl nitrate, zirconium oxide and mixtures thereof.

In one embodiment, the mixed metal oxide catalyst also contains at least one element selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, tungsten, titanium, tin, germanium, zirconium, lithium and hafnium. One or more mixed metal oxide catalysts and activity modifiers include a carrier that is selected from the group consisting of silica, alumina, zirconia, titanium oxide, or mixtures thereof. In addition, the catalytic mixture may contain at least about 0.01 mol of activity modifier per mole of Mo in the mixed metal oxide catalyst. In one aspect of the invention, the mechanical mixing step comprises mixing a calcined mixed metal oxide catalyst and an activity modifier.

In one embodiment, the mixed metal oxide catalyst comprises a mixed oxide defined by the empirical formula:

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

where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li and mixtures thereof; L is selected from the group consisting of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; 0.1≤ a ≤1.0, 0.01≤b≤1.0, 0.001≤c≤0.25, 0≤d≤0.6, 0≤e≤1; n is the number of oxygen atoms necessary to saturate the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a , b, c, d and e is the ratio of the number of moles of the corresponding elements to the number of moles of Mo.

One embodiment provides oxidative ammonolysis of a saturated or unsaturated hydrocarbon or a mixture of saturated and unsaturated hydrocarbons, wherein said contacting step comprises 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 catalytic mixture.

One embodiment of the invention provides the preparation of a dry mixed metal oxide catalyst by non-hydrothermal synthesis.

In addition, one embodiment of the invention provides a mechanical mixing step, which involves mixing an uncalcined or partially calcined dry mixed metal oxide catalyst and an activity modifier to form a mixture, and a subsequent calcining step of the mixture.

Activity modifier

The activity modifier can be mixed with the catalyst before the catalyst is introduced into the reactor. In one or more embodiments, the activity modifier is a compound or mixture of compounds selected from the group consisting of aluminum compounds, antimony compounds, arsenic compounds, boron compounds, cerium compounds, germanium compounds, lithium compounds, molybdenum compounds, neodymium compounds, niobium compounds, phosphorus compounds, selenium compounds, tantalum compounds, tellurium compounds, titanium compounds, tungsten compounds, vanadium compounds, zirconium compounds and mixtures thereof. In one or more embodiments, the activity modifier can be applied to an inert carrier, including, but not limited to, silica, titanium oxide, zirconium oxide, or mixtures thereof.

Examples of aluminum compounds include aluminum nitrate and alumina (Al ₂ O ₃ ). Examples of antimony compounds include antimony oxides, antimony oxalates and antimony tartrates. Specific examples include antimony (III) oxide, antimony (III) oxalate, antimony (III) tartrate and antimony (V) oxide, antimony tetroxide (Sb ₂ O ₄ ) and Sb ₆ O ₁₃ . Examples of arsenic compounds include arsenic (III) oxide, arsenic (V) oxide, and arsenic acid. Examples of a boron compound are boron oxide and boric acid.

Examples of cerium compounds include cerium ammonium nitrate, cerium acetate, cerium (III) oxalate hydrate, and cerium (IV) oxide. An example of germanium compounds is germanium (IV) oxide. Examples of lithium compounds include lithium hydroxide, lithium oxide, lithium nitrate, lithium acetate and lithium tartrate.

Examples of molybdenum compounds include molybdenum (VI) oxide (MoO ₃ ), ammonium heptamolybdate or molybdenum acid. Examples of neodymium compounds include neodymium (III) chloride, neodymium (III) oxide, neodymium (III) isopropoxide and neodymium (III) acetate hydrate. Examples of niobium compounds include ammonium niobium oxalate, niobium oxalate and niobium oxide.

Examples of phosphorus compounds include phosphorus pentoxide and ammonium phosphate. Examples of selenium compounds include selenium dioxide. Examples of tantalum compounds include tantalum (V) oxide. Examples of tellurium compounds include telluric acid, tellurium dioxide and tellurium trioxide.

Examples of titanium compounds include titanium dioxide (TiO ₂ ), (rutile and / or anatase), titanium isopropoxide and (TiO) oxalate. Titanium dioxide is available under the brand name Degussa P-25, Tronox AK-1 and Tronox 8602 (formerly AK-350). Examples of tungsten compounds include tungsten trioxide, tungsten acid and ammonium tungstate. Examples of vanadium compounds include vanadyl oxalate, vanadium (III) oxide, vanadium (IV) oxide, ammonium metavanadate and vanadium (V) oxide. Examples of zirconium compounds are zirconium nitrate and zirconium oxide (ZrO ₂ ).

In one or more embodiments, two or more activity modifiers are used. Modifiers can be added to the catalytic mixture simultaneously or sequentially. Modifiers can be premixed or added separately to the catalyst mixture.

In one embodiment, the activity modifier is solid. a substance that is mechanically mixed with a mixed oxide catalyst to increase catalytic activity. Before use in the method of the present invention, the activity modifier can be thermally or mechanically processed, for example, crushed, sieved and / or pressed.

In other embodiments, the activity modifier may be administered in the form of a solution or suspension that is impregnated with the mixed oxide catalyst composition.

The amount of activity modifier that is added to the catalyst mixture is not particularly limited. In one embodiment, the amount of activity modifier is expressed in moles of activity modifier per mole of molybdenum in all fresh or spent mixed oxide catalyst. In one or more embodiments, the catalytic mixture contains at least about 0.01 mol of activity modifier per mole of molybdenum. In these or other embodiments, the catalyst mixture contains up to about 1.0 mole of activity modifier per mole of molybdenum in the whole freshly prepared or spent mixed oxide catalyst. In one embodiment, the catalytic mixture contains about 0.01-1.0 moles of activity modifier per mole of molybdenum. In another embodiment, the catalytic mixture contains about 0.011-0.5, and in another embodiment, about 0.012-0.2 moles of activity modifier per mole of molybdenum in all fresh or spent mixed oxide catalyst.

In addition, the activity modifier contains a molybdenum compound. The activity modifier may contain antimony (III) oxide, antimony (III) oxalate, antimony (III) tartrate, antimony (V) oxide, antimony tetroxide Sb ₂ O ₄ , germanium (IV) oxide, telluric acid, lithium hydroxide or cerium oxide ( Iv) or a mixture thereof.

In one embodiment, the activity modifier includes antimony (III) oxide, antimony (III) oxalate, antimony (III) tartrate, antimony (V) oxide, antimony tetroxide Sb ₂ O _4, or a mixture thereof. In addition, the activity modifier may also contain a tellurium compound.

In one embodiment, one or more activity modifiers, a freshly prepared mixed metal oxide catalyst, and a spent mixed metal oxide catalyst include a carrier selected from the group consisting of silica, alumina, zirconia, titanium oxide, or mixtures thereof.

The composition of the mixed metal oxide catalyst

The improved method of the present invention is applicable to many compositions of freshly prepared and spent mixed oxide catalysts for oxidative ammonolysis and oxidation. As used herein, the term “freshly prepared catalyst” refers to a catalyst that has not previously been in contact with a feed stream in a reactor. The term "spent catalyst" as used refers to a catalyst that has previously been in contact with a feed stream in a reactor. In some embodiments, the freshly prepared and spent catalysts have the same initial composition, and in other embodiments, the initial compositions of the freshly prepared and spent catalysts are different. The following description of the mixed oxide catalyst composition and its preparation is applicable to both the freshly prepared and spent catalyst composition of this invention.

In one embodiment, the mixed oxide catalyst composition comprises molybdenum, vanadium, niobium, and one or both of antimony and tellurium. In one or more embodiments, the mixed oxide catalyst also includes at least one element selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. In some embodiments, the catalyst composition may include at least one element selected from the group consisting of tungsten, tellurium, titanium, tin, germanium, zirconium, and hafnium. 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, one or both mixed oxide catalysts — freshly prepared and spent — include molybdenum, vanadium, antimony, and niobium, and can be independently described by the empirical formula:

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

where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li 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 ≤1.0,

0.01≤b≤1.0,

0.001≤c≤0.25,

0≤d≤0.6,

0≤e≤1; and

n is the number of carbon oxygen atoms needed to saturate the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a , b, c, d and e are the ratio of the number of moles of the corresponding elements to the number of moles of Mo.

In one or more embodiments where the catalyst compositions are used in an oxidative ammonolysis process, X may be selected from the group consisting of W, Te, Ti, Ge, Sn, Zr, Hf, Li, and mixtures thereof. In other embodiments, X may be selected from the group consisting of W, Te, Ti, Sn, Zr, Hf, Li, and mixtures thereof. In other embodiments of the catalyst compositions described above by the empirical formula, X is an element from among W, Te, Ti, Li, or Sn. In other embodiments of the catalyst compositions described by the empirical formula above, X is W.

In one or more embodiments where the catalyst compositions are used in an oxidative ammonolysis process, L may be selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu . In other embodiments of the catalyst compositions described by the empirical formula above, L is Pr, L is Nd, L is Sm, L is Eu, L is Gd, L is Tb, L is Dy, L is But, L is Er, L is Tm, L is Yb and L is Lu. In other embodiments of the catalyst compositions described by the above empirical formula, L is one of the elements — Nd, Ce, or Pr.

In other embodiments of the catalytic compositions described by the above empirical formula, a , b, end, each independently lies in the following ranges: 0.1≤ a , 0.2 < a , a <0.3, a <0.4, a <0.8, a≤1.0, 0.01≤ b, 0.05 <b, 0.1 <b, b <0.3, b <0.6, b≤1.0, 0.001 <c, 0.01 <c, 0.02 <c, 0.03 <c, 0.04 <c, c <0.05, c <0.1, c <0.15, c <0.2, c≤0.25, 0≤d, 0.001 <d, 0.002 <d, 0.003 <d, 0.004 <d, d <0.006, d <0.01, d <0.02, d <0.05, d < 0.1, d≤0.2, 0≤e, 0.001 <e, e <0.006, e <0.01, e <0.02, e <0.04, e <0.1, e≤1.

The catalyst of the present invention can be either deposited or non-supported (i.e., the catalyst 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 the ratio of Mo to Zr and Ti falls in the range from about 1: 1 to 1:10. Typically, the support serves as a binder for the catalyst and makes it harder and more resistant to abrasion. However, in the case of industrial applications, a selected mixture of both the active phase (i.e., the complex of catalytically active oxides described above) and the support allows one to obtain a catalyst with acceptable activity and hardness (abrasion resistance). Any increase in the amount of active phase leads to a decrease in the hardness of the catalyst. The carrier in the supported catalyst is 10-90 wt.%. Typically, the support in the supported catalyst is 40-60 wt.%. In one embodiment of the present invention, the support in the supported catalyst may comprise as little as 10% by weight. In yet another embodiment of the present invention, the support in the supported catalyst may comprise as little as 30% by weight. In another embodiment of the present invention, the support in the supported catalyst may be even up to 70 wt.%.

Preparation of Mixed Metal Oxide Catalyst

The method of preparation of the catalyst for use in this invention is not critical. Any method known in the art may be used, not limited to hydrothermal synthesis and non-hydrothermal synthesis.

In one or more embodiments, a mixed metal oxide catalyst can be prepared by the hydrothermal synthesis methods described herein. 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 a Mo-V-Nb-Te Mixed Oxidative Oxidative Ammonolysis of Propane", Applied Catalysis A: General, 194- 195, pp. 479-485 (2000), and Ueda et al., “Selective oxidation of light 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.

In general, the catalyst compositions described herein can be prepared by hydrothermal synthesis; for this, the starting compounds (i.e., compounds containing and / or emitting one or more metals for the mixed metal oxide catalyst composition) are mixed in an aqueous solution to form a reaction medium and then the reaction medium is allowed to interact under elevated pressure and elevated temperature in a closed reactor for a time sufficient for the complete reaction to take place with the participation of any organic compounds present in the reaction medium, for example, solvents used for rigotovleniya catalyst or any organic compounds added with any of the starting compounds containing components of the mixed metal oxide catalyst composition.

The starting compounds are reacted in a closed reaction vessel at a temperature above 100 ° C and elevated pressure. 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 50 psi. inch and in another embodiment, at a pressure of at least about 100 psi. inch. In one or more embodiments, the starting compounds are reacted in a closed reaction vessel at a pressure of up to about 300 psi. inch. Such closed reaction vessels may be provided with pressure monitoring devices to avoid excessive pressure build-up in the vessel and / or to control the reaction pressure.

The starting compounds can be introduced into the reaction by a method that involves mixing the starting compounds during the reaction. A particular mixing mechanism is not critical and may include, for example, mixing the components (e.g., stirring or stirring) during the reaction step in any effective manner. Such methods include, for example, mixing the components in the reaction vessel by shaking, turning or vibration. Such methods also include, for example, stirring with a stirrer located at least partially inside the reaction vessel and driven by an engine coupled to the stirrer or reaction vessel to propel the stirrer and 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 for an effective reaction between the components of the reaction medium to form a more uniform reaction medium (for example, leading to a more uniform 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 provides easier isolation and separation of the obtained mixed metal oxide by methods such as centrifugation, decantation or filtration, and avoids the need to extract a significant portion 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 method of mixing 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, either with reagents of the O ₂ type, or even an inert gas of the Ar or N _{2 type} . 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 resulting mixed metal oxide is a solid solution containing the necessary elements, as described above, and at least part of it is characterized by the necessary crystal structure of the catalysts for active and selective catalytic oxidation and / or oxidative ammonolysis of propane or isobutane. The exact reaction time is not strictly critical and may be, for example, at least about three hours, at least 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 aces or at least about sixty-six hours or 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, at least about three weeks, or at least about one month.

Some starting compounds containing or releasing metal components used in the synthesis of catalysts (also referred to herein as the “source” or “sources”) can be introduced into the reaction vessel in the form of aqueous solutions of metal salts. Some starting compounds may be introduced into the reaction vessel as solids or a suspension of solid particles in non-aqueous solvents or other non-aqueous media.

Examples of sources for the synthesis of catalysts described herein include the following. Examples of lithium sources include lithium hydroxide, lithium oxide, lithium acetate, lithium tartrate and lithium nitrate. Examples of sources of vanadium include vanadyl sulfate, ammonium metavanadate and vanadium (V) oxide. Examples of sources of antimony include antimony (III) oxide, antimony (III) acetate, antimony (III) oxalate, antimony (V) oxide, antimony (III) sulfate and antimony (III) tartrate. Examples of sources of niobium include niobium oxalate, ammonium niobium oxalate, niobium oxide, niobium ethoxide and niobic acid.

Sources of tungsten include ammonium metatungstate, tungsten acid, and tungsten trioxide. Sources of tellurium include telluric acid, tellurium dioxide, tellurium trioxide, organic tellurium compounds such as methyltellurol and dimethyltellurol.

Sources of titanium include titanium dioxide (TiO ₂ ) (rutile and / or anatase), titanium isopropoxide, TiO (oxalate), TiO (acetylacetonate) ₂ and titanium alkoxide complexes, for example, Tyzor 131. Titanium dioxide is sold under the brand names Degussa P-25, Tronox AK-1 and Tronox 8602 (formerly AK-350). Sources of tin include tin (II) acetate. Sources of germanium include germanium (IV) oxide. Sources of zirconium include zirconyl nitrate. or zirconium (IV) oxide. Sources of hafnium include hafnium (IV) chloride and hafnium (IV) oxide.

Sources of lanthanum include lanthanum (III) chloride, lanthanum (III) oxide, and lanthanum (III) acetate hydrate. Sources of cerium include cerium (III) chloride, cerium (III) oxide, cerium (III) isopropoxide and cerium (III) acetate hydrate. Sources of praseodymium include praseodymium (III) chloride, praseodymium oxide (III, IV), praseodymium (III) isopropoxide and praseodymium (III) acetate hydrate. Sources of neodymium include neodymium (III) chloride, neodymium (III) oxide, neodymium (III) isopropoxide and neodymium (III) acetate hydrate. Sources of samarium include samarium (III) chloride, samarium (III) oxide, samarium (III) isopropoxide and samarium (III) acetate hydrate. Sources of europium include europium (III) chloride, europium (III) oxide and europium (III) acetate hydrate. Sources of gadolinium include gadolinium (III) chloride, gadolinium (III) oxide and gadolinium (III) acetate hydrate. Sources of terbium include terbium (III) chloride, terbium (III) oxide and terbium (III) acetate hydrate. Sources of dysprosium include acetate (III) chloride hydrate, dysprosium (III) oxide, dysprosium (III) isopropoxide and dysprosium (III) acetate hydrate. Sources of holmium include holmium (III) chloride, holmium (III) oxide and holmium (III) acetate hydrate. Erbium sources include erbium (III) chloride, erbium (III) oxide, erbium (III) isopropoxide and erbium (III) acetate hydrate. Sources of thulium include thulium (III) chloride, thulium (III) oxide and thulium (III) acetate hydrate. Sources of ytterbium include ytterbium (III) chloride, ytterbium (III) oxide, ytterbium (III) isopropoxide and ytterbium (III) acetate hydrate. Sources of lutetium include lutetium (III) chloride, lutetium (III) oxide and lutetium (III) acetate hydrate. Nitrates of the above metals can also be used as sources of compounds.

The amount of aqueous solvent in the reaction medium may vary due to different solubilities of the starting compounds combined to form a particular mixed metal oxide. The amount of aqueous solvent should be at least sufficient to form a suspension of reagents (a mixture of solids and liquids that can be mixed). Typically, hydrothermal synthesis of mixed metal oxides leaves space in the reaction vessel.

The catalyst preparation steps following the reaction step may include processing steps, for example, cooling a reaction medium containing a mixed metal oxide (e.g. to room temperature), separating solid particles consisting of the mixed metal oxide from a liquid (e.g., by centrifugation and / or by decanting the top layer or alternatively by filtration), washing the separated solid particles (for example, with distilled or deionized water), a repeated separation step, single or multiple washing and effective final separation step. In one embodiment, the processing step includes drying the reaction medium, for example, using a rotary evaporator, spray drying, freeze drying, or similar liquid removal methods.

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

In one or more embodiments of the present invention, a mixed metal oxide catalyst may be prepared by the non-hydrothermal synthesis method described herein. Non-hydrothermal syntheses are also disclosed in US Patent Application No. 2006/0235238 to Satoru Komada and Sadao Shoji, and to WO 2006/019078, Kato Takakai and Fukushima Satoshi, which are incorporated herein by reference.

One embodiment of non-hydrothermal synthesis can be described as follows. The first aqueous solution / suspension is prepared by combining by heating and stirring a molybdenum source, a vanadium source, an antimony source, optionally other starting compounds, hydrogen peroxide and a carrier gel, for example, silica sol. A second aqueous solution / suspension is prepared by combining by heating and stirring a source of niobium, optionally dicarboxylic acid and optionally other starting compounds. The first and second solutions / suspensions are combined to form a third aqueous solution / suspension. The precipitate or suspended solids can be removed and the aqueous mixture dried to form a dry mixed metal oxide catalyst. Various processing steps and drying and / or calcining methods can be used.

In one embodiment, the non-hydrothermal synthesis can be specifically described as follows: the first aqueous solution / suspension is (A) and the second aqueous solution / suspension is (B). Ammonium heptamolybdate, ammonium metavanadate and antimony trioxide are added to water, then the resulting mixture is heated to a temperature of at least 50 ° C to obtain an aqueous mixture (A). It is preferable to heat the mixture with stirring. It is better to heat the aqueous mixture to temperatures ranging from about 70 ° C to the normal boiling point of the mixture. Can be heated under reflux. In the case of heating under reflux, the boiling point is usually in the range of about 101-102 ° C. Elevated temperatures can be maintained for about 0.5 hours or more. When heated to temperatures of about 80-100 ° C, the heating time is usually about 1-5 hours. At relatively low heating temperatures (for example, below about 50 ° C), longer heating is required.

After heating, as described above, optionally hydrogen peroxide and / or a carrier sol, such as a silica sol, may be added to the aqueous mixture. When hydrogen peroxide is added to the aqueous mixture (A), the amount of hydrogen peroxide should be such that the molar ratio of hydrogen peroxide to antimony (molar ratio of H ₂ O ₂ / Sb) based on antimony is in the range of about 0.01-20, in one embodiment, in the range of about 0.5-3, in another embodiment, the range of about 1-2.5. After the addition of hydrogen peroxide, the aqueous mixture (A) can be stirred at temperatures in the range of about 30-70 ° C. for about 30 minutes to about 2 hours.

In one or more embodiments, an aqueous solution / suspension (B) can be prepared by combining water, a source of niobium, optionally dicarboxylic acid and / or other starting compounds by heating and stirring to obtain a preliminary niobium-containing aqueous solution or niobium-containing aqueous mixture with a suspended portion of the niobium compound. Then the preliminary niobium-containing aqueous solution or niobium-containing aqueous mixture is cooled, and if dicarboxylic acid is added, part of it precipitates. The cooling step is followed by the removal of precipitated dicarboxylic acid from a pre-niobium-containing aqueous solution, or the precipitation of dicarboxylic acid and suspended niobium compound from a niobium-containing aqueous mixture, and obtaining a niobium-containing aqueous liquid (B).

In one embodiment, an aqueous liquid (B) can be prepared by adding a niobium compound (e.g., niobic acid) to water, followed by heating the resulting mixture to a temperature in the range of about 50-100 ° C. If the niobium compound is niobic acid, dicarboxylic acid can also be added. Dissolution of the niobium compound can be accelerated by the addition of a small amount of aqueous ammonia.

Examples of suitable dicarboxylic acids include oxalic acid. In one embodiment, niobium and oxalic acids are added to the water, then the resulting mixture is heated and stirred to obtain an aqueous liquid (B). Typically, the molar ratio of dicarboxylic acid to niobium compound based on niobium is in the range of about 1-4, in one embodiment, in the range of about 2-4.

In other embodiments, the niobium source includes niobium acid oxalate or ammonium niobium oxalate. When using niobium acid oxalate or ammonium niobium oxalate as a niobium compound, dicarboxylic acid is not needed.

In general, the niobium source may be added as a solid, mixture or dispersion in a suitable medium. If the niobium compound is niobic acid, then to remove acidic impurities that may be contaminated with niobic acid when it is prepared, the niobic acid can be washed with aqueous ammonia and / or water before use. As a niobium compound, it is better to use a freshly prepared niobium compound. However, a slightly aged niobium compound can be used (for example, due to dehydration) as a result of long-term storage, etc.

The concentration of the niobium compound (calculated as niobium) in the preliminary niobium-containing aqueous solution or aqueous mixture is maintained, in one or more embodiments, in the range of about 0.2-0.8 mol / kg of solution or mixture. In one or more embodiments, dicarboxylic acid is used in an amount such that the molar ratio of dicarboxylic acid to niobium compound based on niobium is about 2-6. 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, the amount of dicarboxylic acid that precipitates upon cooling the resulting pre-aqueous solution of a niobium-containing compound or mixture may be too large, which reduces the amount of dicarboxylic acid used. On the other hand, when insufficient dicarboxylic acid is used, a large amount of the niobium compound may remain undissolved and suspended in the aqueous solution or in the mixture and can then be removed from the aqueous mixture, which reduces the degree of use of the niobium compound.

Any cooling method may be used. For example, you can simply cool with an ice bath.

Precipitated dicarboxylic acid (or precipitated dicarboxylic acid and a dispersed niobium compound) can be easily separated by conventional methods, for example, 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 2-6, either the niobium compound or dicarboxylic acid can be added to the aqueous liquid (B) so that the dicarboxylic acid / niobium molar ratio is the solution fell into the specified interval. However, usually this operation is not needed, because an aqueous liquid (B) with a molar ratio of dicarboxylic acid / niobium in the range of about 2-4 can be prepared by adjusting the concentration of the niobium compound, the ratio of dicarboxylic acid / niobium and the cooling temperature of the above preliminary niobium-containing aqueous solution or aqueous mixture.

Aqueous liquid (B) may also contain additional components. In one or more embodiments, the aqueous liquid (B) may also contain hydrogen hydroxide (H ₂ O ₂ ). In these or other embodiments, the aqueous liquid (B) may also contain one or more antimony compounds (e.g. antimony trioxide), a titanium compound (e.g. titanium dioxide, which may be a mixture of rutile and anatase), and a cerium compound (e.g. cerium acetate) . In one embodiment, the amount of hydrogen peroxide is such that the molar ratio of hydrogen peroxide and niobium compound (molar ratio of H ₂ O ₂ / Nb) calculated as niobium is in the range of 0.5-20, and in another embodiment, is in the range of 1-20. In some embodiments, the antimony compound is mixed with at least a portion of the aqueous liquid (B) and hydrogen peroxide so that the molar ratio (Sb / Nb molar ratio) of the antimony compound based on antimony and the niobium compound based on niobium is not more than about 5 and in one embodiment was in the range of about 0.01-2.

The aqueous mixture (A) and the aqueous liquid (B) can be mixed together in the desired ratio to form an aqueous solution / suspension. The ratio of (a) to (b) will correspond to the desired catalyst composition. The amount of solids in the aqueous mixture usually begins with about 10 wt.%. In one embodiment, the amount of solids in the aqueous mixture is about 10-60 wt.%, In another embodiment, about 15-55 wt.% And in another embodiment, the amount of solids in the mixture is about 20-50 wt.% Based on the total weight of the mixture.

In one or more embodiments, when a catalyst supported on silica is desired, an aqueous solution / suspension is formulated to contain a silica source (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.

The aqueous solution / suspension may be dried to remove liquid. Drying can be carried out by conventional methods, for example, 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.

The aqueous solution / suspension can be dried to remove part of the liquid. Drying can be carried out by conventional methods, for example, spray drying or evaporation. Particularly applicable is spray drying, 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. It is better that the temperature of the spray dryer at the entrance to the drying zone is 150-300 ° C.

The dried substance obtained by either the hydrothermal or non-hydrothermal method can be called a dry mixed metal oxide catalyst. It is understood that the terms “dry” and “dried” refer to a solid substance from which most of the liquid has been removed, but some moisture remains. Therefore, unless otherwise indicated, the terms “dry” and “dried” should be interpreted to mean an almost dry state. For the purposes of this description, the term “dry mixed metal oxide catalyst” is continued to refer to this substance having undergone optional post-treatment, including calcination and grinding, as shown below. In addition, the term “dry mixed metal oxide catalyst” may refer to a catalyst that has been used in a reactor. Thus, the dry mixed metal oxide catalyst can be calcined or non-calcined, crushed, crushed, granular, extruded or molded in another way, and can also be fresh or spent.

As already mentioned, the dried mixed metal oxide catalyst can be further processed. Such treatments may include, for example, calcination (including heat treatment under oxidizing or reducing conditions) in the atmosphere of various gases. The dry mixed metal oxide catalyst may be crushed or ground before such treatment and / or pulsed during such processing. In one embodiment, for example, the dry mixed metal oxide may optionally be crushed and then calcined.

Calcination can be carried out in an inert, reducing or oxidizing atmosphere. In one embodiment, the calcination is at least partially carried out in an inert gas atmosphere (for example, in an inert gas stream), such as nitrogen, which is substantially free of oxygen. In one or more embodiments, the calcination conditions include a temperature range of about 200-700 ° C, in other embodiments, about 400-650 ° C.

In one or more embodiments, the heating temperature of the dry mixed metal oxide catalyst is continuously or stepwise increased from less than about 400 ° C to about 550 ° C and about 700 ° C. In some embodiments, multistage calcination can be used. In these embodiments, the dry mixed metal oxide catalyst can be partially calcined at a relatively low temperature of at least about 200 ° C, and then at one or more higher temperatures of at least about 400 ° C within the above ranges.

For use in the method of the present invention, the treated (eg, calcined) mixed metal oxide can also be machined, for example, crushed, sieved and pressed into the final form.

In other embodiments, the catalyst may be formed into a final shape prior to all calcining or other heat treatment operations. For example, when preparing a fixed-bed catalyst, a suspension of the catalyst precursor is usually dried by heating at elevated temperature and then molded (for example, extruded, granulated, etc.) to the catalyst particles of the desired size and configuration prior to calcination. Similarly, in the preparation of catalysts in a fluidized bed, the suspension of the catalyst precursor is spray dried and microspherical catalyst particles with a diameter in the range of about 10-200 μm are obtained; then the catalyst is calcined. Variants of these methods are known to those skilled in the art.

Calcination is carried out in a drum furnace, in a fluidized bed furnace, or the like. In one or more embodiments, calcination is carried out in an unsteady mode in order to avoid complications associated with calcination (leading to deterioration of properties and / or destruction or cracking of the obtained catalyst).

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. It is better to preselect the calcination conditions so that the resulting catalyst contains one or more crystalline phases.

A method of obtaining a mechanical mixture

The catalyst mixture can be prepared by combining a freshly prepared catalyst composition, a spent catalyst composition and an activity modifier by mechanical mixing, wet impregnation, or a combination of these methods. You can pre-mix one or more components. The mixing order is not critical. In one embodiment, an activity modifier and a freshly prepared catalyst can be mixed in advance and then mixed with the spent catalyst. An activity modifier can be added at any stage in the preparation of a freshly prepared catalyst composition. However, in some embodiments, an increase in activity is observed when a modifier is added to the final composition of a freshly prepared catalyst.

In one embodiment, the activity modifier and spent catalyst can be mixed and then mixed with freshly prepared catalyst. In yet another embodiment, the activity modifier is a solid and can be finely divided to combine with the catalyst compositions. In another embodiment, the activity modifier may consist of larger particles, i.e. the same order as the catalyst particles.

In one or more embodiments, an activity modifier may be added to the spent and freshly prepared catalyst compositions by wet impregnation. In one embodiment, the mechanical mixture of an activity modifier, a freshly prepared mixed oxide catalyst and spent mixed oxide catalyst may be heat treated or calcined.

In some embodiments, when using two or more activity modifiers, they can be added to the catalyst composition individually or premixed to form a modifying mixture. The mixture of modifiers can then be mixed with the mixed oxide catalyst composition by mechanical mixing or impregnation.

Conversion of propane and isobutane by oxidative ammonolysis and oxidation

The present invention provides a process for converting propane to acrylonitrile and isobutane to methacrylonitrile. The method includes preparing a mixture of an activity modifier, a freshly prepared metal oxide catalyst composition and a spent metal oxide catalyst composition as described above, and contacting the catalyst mixture with propane or isobutane in the presence of oxygen (for example, a feed containing an oxygen-containing gas, usually air, entering the reaction zone) and ammonia under reaction conditions effective to form acrylonitrile or methacrylonitrile. The feed stream for this reaction includes propane or isobutane, an oxygen-containing gas such as air, and ammonia. In one or more embodiments, the molar ratio of propane or isobutane to oxygen is about 0.125-5, in another embodiment, about 0.25-4.5, and in another embodiment, about 0.35-4. In one or more embodiments, the molar ratio of propane or isobutane to ammonia is about 0.3-4, and in another embodiment, about 0.5-3. The feed stream may also include one or more additional feed components, including the resulting acrylonitrile or methacrylonitrile (for example, from a recycle stream or from an earlier stage in a multi-stage reactor) and / or water vapor. For example, a feed stream may include about 5-30% by weight of additional feed components based on the total weight of the feed stream or in moles relative to the amount of propane or isobutane in the feed stream. In one embodiment, the process described herein for the oxidative ammonolysis of propane to acrylonitrile is a one-pass process, i.e. it proceeds without recycling the unreacted starting reagents.

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, supplied to the reaction zone in a stream of oxygen-containing gas, usually air) under conditions reactions effective for the formation of acrylic acid. Preferably, the feed stream for this reaction contains propane or isobutane in a ratio with oxygen in the range of about 0.15-5 and preferably about 0.25-2. The feed stream also contains one or more additional components, including the obtained acrylic acid or methacrylic acid (for example, from a recycle stream or from an earlier stage in a multi-stage reactor) and / or water vapor. For example, the feed stream may be about 5-30 wt.% Based on the total weight of the feed stream or in moles relative to the 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 reactor system. 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 catalytic mixture, 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 to acrylic acid or the conversion of isobutane to methacrylonitrile or methacrylic acid, respectively. Typically, reaction conditions include a temperature range of about 300-550 ° C, in one embodiment, 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 psi. inch to about 200 psi inch, in one embodiment, from about 0 psi. inch to about 100 psi inch and in some embodiments from about 0 psi. inch to about 50 psi 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 per hour.

The resulting acrylonitrile and / or acrylic acid or methacrylonitrile and / or methacrylic acid can, if necessary, be separated from other by-products and / or from unreacted reagents by methods known in the art. By-products of oxidative ammonolysis may include CO _x (carbon dioxide + carbon monoxide), hydrocyanic acid (HCN) and acetonitrile or methyl cyanide (CH ₃ CN). Exhaust gases from the reactor may contain unreacted oxygen (O ₂ ), ammonia (NH ₃ ), nitrogen (N ₂ ), helium (He) and entrained small particles of the catalyst

EXAMPLES

To illustrate the present invention, samples of catalytic mixtures were prepared and then tested under similar reaction conditions. The compositions below are nominal and contain all metals taken to prepare the catalytic mixture. Since some metals may be lost or may not fully react during the preparation of the catalyst, the actual composition of the final catalyst mixture may slightly differ from the nominal compositions given below.

Fresh catalyst was prepared in its final form by the methods described herein. A portion of the freshly prepared catalyst was combined with a spent catalyst and a catalyst activity modifier and mixed dry with a mechanical mixer.

The catalyst was tested in a 40 cm ³ fluidized bed reactor with a diameter of 1 inch. About 20-45 g of catalyst particles or catalyst mixture were charged into the reactor. Propane was fed into the reactor at a rate of 0.04-0.15 WWH (i.e., propane mass / catalyst mass / hour). Typically, ammonia was fed into the reactor at such a rate that the ratio of ammonia to propane was about 1-1.5. The pressure in the reactor was maintained in the range of about 2-15 psi. inch. The reaction temperature was in the range of about 420-460 ° C.

Comparative Example 1 — A catalyst of nominal composition was prepared: MoV _0.2 1Sb _0.24 Nb _0.09 O _x , which contained 45% by weight of a silica support. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 1.

Example 1-1 - The spent catalyst from comparative example 1 was combined with a freshly prepared catalyst of nominal composition MoV _0.21 Sb _0.24 Nb _0.09 O _x in a ratio of 2/3 of spent catalyst per 1/3 of freshly prepared catalyst and was also combined with Sb ₂ O ₃ in an amount of 0.1 mol Sb per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm fluidized bed reactor. The results are shown in table 1.

Comparative Example 2 — A catalyst of the same nominal composition was prepared as in comparative example 1. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 1

Example 2-1 - The spent catalyst from comparative example 2 was combined with a freshly prepared catalyst of nominal composition MoV _0.21 Sb _0.24 Nb _0.09 O _x in a ratio of 2/3 of spent catalyst per 1/3 of freshly prepared catalyst and was also combined with MoO ₃ in an amount of 0.02 mol Mo per Mo mole in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 1.

Example 2-2 - The spent catalyst from comparative example 2-1 was combined with a freshly prepared catalyst of nominal composition MoV _0.2 1Sb _0.24 Nb _0.09 O _x in a ratio of 2/3 of the spent catalyst per 1/3 of the freshly prepared catalyst and was also combined with Sb ₂ O ₃ in an amount 0.1 mol of Sb per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 1.

Comparative Example 3. A catalyst of nominal composition was prepared: MoV _0.21 Sb _0.24 Nb _0.09 O _x , which contained 45% by weight of a silica support. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Example 3-1 - The catalyst from comparative example 3 was combined with 0.05 mol Sb ₂ O ₃ per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Example 3-2 - The catalyst from comparative example 3 was combined with 0.1 mol of Sb ₂ O ₃ per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Example 3-3 - The catalyst from comparative example 3 was combined with 0.2 mol of Sb ₂ O ₃ per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Example 3-4 - The catalyst from comparative example 3 was combined with 0.02 mol of TiO ₂ per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Example 3-5 - The catalyst from comparative example 3 was combined with 0.02 mol of H ₆ TeO ₆ per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Example 3-6 — The catalyst of comparative example 3 was combined with 0.1 mol of Sb ₂ O ₃ per mole of Mo. The catalyst was tested in a 40 cm ³ fluidized bed reactor. Data on activity after prolonged use are summarized in table 2.

Example 3-7 - The catalyst of comparative example 3 was combined with 0.05 mol of H ₃ BO ₃ per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Example 3-8 - The catalyst of comparative example 3 was combined with 0.1 mol of Sb ₂ O ₄ per mole of Mo. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Examples 3-9 - The catalyst of comparative example 3 was combined with 0.05 mol (NH ₄ ) ₂ HPO ₄ per mole of Mo. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Example 3-10 - The catalyst from comparative example 3 was combined with 0.04 mol of LiOH per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 2.

Comparative Example 4. A catalyst of nominal composition was prepared: MoV _0.3 Sb _0.2 Nb _0.08 Ti _0.1 Ce _0.005 O _x , which contained 45 wt.% Of the support — silicon oxide. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 3.

Example 4-1 - The catalyst from comparative example 4 was combined with 0.025 mol of GeO ₂ per mole of Mo in the composition of the base catalyst. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 3.

Example 4-2 — The catalyst of comparative example 4 was combined with 0.025 mol of CeO ₂ per mole of Mo in the base catalyst composition. The catalyst was tested in a 40 cm ³ fluidized bed reactor. The results are shown in table 3.

Although the above description and the above 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 (13)

1. The method of oxidative ammonolysis of a saturated hydrocarbon to obtain an unsaturated nitrile, including:
preparation of a catalytic mixture containing
a freshly prepared mixed metal oxide catalyst comprising molybdenum, vanadium, niobium and at least one element selected from the group consisting of antimony and tellurium, and optionally containing at least one element selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, tungsten, titanium, tin, germanium, zirconium, lithium, and hafnium, and optionally contains a carrier selected from the group consisting of silicon oxide Aluminum oxide, zirconium oxide, titanium oxide or mixtures thereof;
a spent mixed metal oxide catalyst comprising molybdenum, vanadium, niobium and at least one element selected from the group consisting of antimony and tellurium, and optionally containing at least one element selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, tungsten, titanium, tin, germanium, zirconium, lithium, and hafnium, and optionally contains a carrier selected from the group consisting of silicon oxide oxide alumina, zirconium oxide, titanium oxide or mixtures thereof,
an activity modifier selected from the group consisting of antimony (III) oxide, antimony (III) oxalate, antimony (III) tartrate, antimony (V) oxide, antimony tetroxide, Sb ₆ O ₁₃ and mixtures thereof; and
contacting a saturated hydrocarbon with an oxygen-containing gas and ammonia in the presence of a catalytic mixture. 2. The method according to claim 1, in which the catalytic mixture contains at least about 0.01 mol of activity modifier per mole of Mo in the total amount of freshly prepared and spent mixed metal oxide catalysts. 3. The method according to claim 1, in which one or both of the freshly prepared and spent mixed metal oxide catalysts are prepared using the method of non-hydrothermal synthesis. 4. The method according to claim 1, in which the composition of the freshly prepared catalyst comprises a mixed metal oxide defined by the empirical formula:
Mo ₁ V _a Sb _b Nb _c X _d L _e O _n ,
where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li and mixtures thereof; L is selected from the group consisting of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; 0.1≤a≤1.0, 0.01≤b≤1.0, 0.001≤c≤0.25, 0≤d≤0.6, 0≤e≤1; n is the number of oxygen atoms necessary to saturate the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a, b, c, d and e is the ratio of the number of moles of the corresponding element to the number of moles of Mo. 5. The method according to claim 1, in which the composition of the spent catalyst is a mixed oxide defined by the empirical formula:
Mo ₁ V _a Sb _b Nb _c X _d L _e O _n ,
where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li and mixtures thereof; L is selected from the group consisting of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; 0.1≤a≤1.0, 0.01≤b≤1.0, 0.001≤c≤0.25, 0≤d≤0.6, 0≤e≤1; n is the number of oxygen atoms necessary to saturate the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a, b, c, d and e is the ratio of the number of moles of the corresponding element to the number of moles of Mo. 6. The method according to claim 1, wherein the preparation step comprises mechanically mixing a freshly prepared mixed oxide catalyst, a spent freshly prepared mixed oxide catalyst, and an activity modifier. 7. The method according to claim 6, in which the preparation step also includes pre-mixing the composition of a freshly prepared mixed oxide catalyst and an activity modifier. 8. The method according to claim 1, wherein the preparation step comprises combining a freshly prepared mixed oxide catalyst and an activity modifier by wet impregnation. 9. The method of oxidative ammonolysis of a saturated hydrocarbon to obtain an unsaturated nitrile, including:
mechanically mixing a dry mixed metal oxide catalyst and an activity modifier to form a catalyst mixture, the mixed metal oxide catalyst containing molybdenum, vanadium, niobium and at least one element selected from the group consisting of antimony and tellurium and optionally containing at least one element selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, tungsten, titanium, tin, germanium, zirconium, lithium, and hafnium, and optionally contains a carrier selected from the group consisting of silicon oxide, aluminum oxide, zirconium oxide, titanium oxide or mixtures thereof, and the activity modifier is selected from the group consisting of antimony (III) oxide, antimony (III) oxalate, antimony (III) tartrate, antimony (V) oxide, antimony tetroxide, Sb ₆ O ₁₃ and mixtures thereof; and
contacting a saturated hydrocarbon with an oxygen-containing gas and ammonia in the presence of a catalytic mixture. 10. The method according to claim 9, in which the catalytic mixture contains at least about 0.01 mol of activity modifier per mole of Mo in the mixed metal oxide catalyst. 11. The method according to claim 9, in which the stage of mechanical mixing includes mixing the calcined mixed metal oxide catalyst with an activity modifier. 12. The method according to claim 9, in which the mixed metal oxide catalyst comprises a mixed oxide defined by the empirical formula:
Mo ₁ V _a Sb _b Nb _c X _d L _e O _n ,
where X is selected from the group consisting of W, Te, Ti, Sn, Ge, Zr, Hf, Li and mixtures thereof; L is selected from the group consisting of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof; 0.1≤a ≤ 1.0, 0.01≤b≤1.0, 0.001≤c≤0.25, 0≤d≤0.6, 0≤e≤1; n is the number of oxygen atoms necessary to saturate the valency of all other elements of the mixed oxide, provided that one or more of the remaining elements in the mixed oxide can be in the oxidation state lower than the higher oxidation state, a, b, c, d and e is the ratio of the number of moles of the corresponding element to the number of moles of Mo. 13. The method according to claim 9, in which a dry mixed metal oxide catalyst is prepared by the method of non-hydrothermal synthesis.