METHOD FOR TREATING OR REGENERATING METAL CATALYST AND APPLICATION

Abstract

The present invention relates to a method for preparing, activating and regenerating a metal supported catalyst, comprising: treating a M.sub.a-M.sub.b-M.sub.c metal supported catalyst at 10-700? C. by using an ammonia or nitrogen-containing organic matter, wherein the M.sub.a metal is an active metal selected from one or more of a noble metal atom or a transition metal, the support is a common industrial porous catalyst, and the M.sub.a metal is dispersed on the support in a state of single atomic site. According to the M.sub.d-M.sub.b-M.sub.c metal supported noble metal/zinc catalyst treated by the method of the present invention, the direct dehydrogenation conversion rate and selectivity of catalyzing light alkanes are remarkably improved; the method for preparing the catalyst is simple in process, the catalytic activity after regeneration is still kept, and the catalyst can be industrially produced on a large scale.

Claims

1. A method for treating metallic catalyst comprising: treating metal supported catalyst with ammonia or nitrogen-containing organic at 10? C.-700? C., the metal supported catalyst is a M.sub.a-M.sub.b-M.sub.c metal supported catalyst, wherein M.sub.a is active metal which is selected from one or more of noble metal and transition metal, wherein the noble metal is selected from one or more mixtures of Pt, Au, Ru, Rh, Pd, Ir and Ag, the transition metal is selected from La, Fe, Co, Mn, Cr, Ni and Cu, the content of M.sub.a is 0.01-5 wt % based on catalyst weight; M.sub.b is selected from one or more combinations of Zn, Sn, Co and Al, the content of M.sub.b is 0.1-20 wt % based on catalyst weight; M.sub.c is selected from K, Na and the mixture thereof, the content of M.sub.c is 0-2.0 wt %, and a support of the metal supported catalyst comprises alumina, silica-alumina, zirconia, cerium oxide, titanium oxide, or molecular sieves or the mixture thereof.

2. The method according to claim 1, wherein the metal supported catalyst does not contain M.sub.c, wherein M.sub.a is Pt, Ru, Pd, Ir, Cr, Ni, PtPd, IrPt, IrPd, or IrPtPd; M.sub.b is Zn, Co or ZnCo mixture; the support is commonly used in industry, which comprises alumina, silica-alumina, zirconia, cerium oxide, titanium oxide, or molecular sieves or the mixture thereof; alternatively, the support is ?-alumina, titanium oxide, silica, NaY molecular sieve supports; the shape of the support is selected from non-formed powder, and shaped structure; the shaped structure is selected from spherical shape, strip shape, cylindrical shape, shape with multi-porous channels, honeycomb shape.

3. The method according to claim 2, wherein the M.sub.a metal is loaded on the support in a state of single-atom sites, or in a state of coexistence of single-atom sites with clusters and/or nanoparticles; alternatively, the M.sub.a metal is loaded on the support in the state of single-atom sites, or in the state of coexistence of single-atom sites and clusters, or in the state of coexistence of single-atom sites, clusters and nanoparticles; the content of M.sub.a is 0.01-5 wt % or 0.05-2 wt % based on catalyst weight; the content of M.sub.b is 0.1-20 wt %, 0.1-10 wt %, or 0.5-4 wt % based on catalyst weight.

4. The method according to claim 3, wherein the metal supported catalyst is prepared by loading a M.sub.a metal precursor and a M.sub.b precursor on the support; the loading of M.sub.a and M.sub.b metal is carried out simultaneously or sequentially.

5. The method according to claim 2, wherein the ammonia comprises ammonia gas or substance that can release ammonia; the nitrogen-containing organic is selected from C.sub.1-6 alkyl amine, C.sub.2-6 alkenyl amine, C.sub.6-20 aryl amine, C.sub.4-20 cyclic alkyl amine, C.sub.4-20 nitrogen-containing heterocyclic ring, C.sub.4-20 nitrogen-containing heteroaromatic ring and (RCO).sub.xNR.sub.3-x, wherein R is H or C.sub.1-6 alkyl, x is 1 or 2; the amine is monamine or polyamine; alternatively, the alkyl, alkenyl, aryl, nitrogen-containing heterocycle ring and nitrogen-containing heteroaromatic ring are independently further substituted by oxygen, carbonyl, carboxyl, ester group, or amino group; the aryl is monocyclic aryl or fused polycyclic aryl; the nitrogen-containing heterocyclic ring is monocyclic or fused non-aromatic ring containing cyclic nitrogen atom, and a cyclic carbon atom is optionally replaced by oxygen; the nitrogen-containing heteroaromatic ring is monocyclic or fused polycyclic heteroaromatic ring containing cyclic nitrogen atom, and a cyclic carbon atom is optionally replaced by oxygen; alternatively, the nitrogen-containing organic is selected from C.sub.1-6 alkyl amine, C.sub.1-6 alkyl diamine, C.sub.6-20 aryl amine, dimethyl formamide; alternatively, the nitrogen-containing organic is selected from ethylenediamine, triethylamine, butylamine, aniline and dimethyl formamide; alternatively, the nitrogen-containing organic is ethylenediamine.

6. The method according to claim 2, treating the metal supported catalyst with ammonia or gaseous nitrogen-containing organic, or treating metal supported catalyst with NH.sub.3 gas, nitrogen-diluted NH.sub.3 gas, nitrogen-diluted gaseous nitrogen-containing organic; the treatment temperature is in the range of 10? C. to 700? C. or in the range of 300? C. to 600? C.; the treatment time is 1-400 min, or 5-150 min.

7. The method according to claim 1, wherein M.sub.a is Ir, M.sub.b is selected from Zn, Sn and mixture thereof, M.sub.c is selected from K, Na and mixture thereof, the content of M.sub.a is 0.1-2 wt % based on catalyst weight, the content of M.sub.b is 0.1-3.0 wt % based on catalyst weight, the content of M.sub.c is 0.1-2.0 wt % based on catalyst weight; the support is alumina support or shaped alumina support; the M.sub.a metal is dispersed and loaded on the support in a state of single-atom sites, or clusters, or nanoparticles; alternatively, the M.sub.a metal is loaded on the support in a state of single-atom sites, or in the state of coexistence of single-atom sites with clusters and/or nanoparticles; wherein the ammonia comprises ammonia gas or substance that can release ammonia; the nitrogen-containing organic is selected from C.sub.1-6 alkyl amine, C.sub.2-6 alkenyl amine, C.sub.6-20 aryl amine, C.sub.4-20 cyclic alkyl amine, C.sub.4-20 nitrogen-containing heterocyclic ring, C.sub.4-20 nitrogen-containing heteroaromatic ring and (RCO).sub.xNR.sub.3-x, wherein R is H or C.sub.1-6 alkyl, X is 1 or 2; the amine is a monamine or polyamine; optionally, the alkyl, alkenyl, aryl, nitrogen-containing heterocycle ring, nitrogen-containing heteroaromatic ring are independently further substituted by oxygen, carbonyl, carboxyl, ester group, or amino group; the aryl is monocyclic aryl or fused polycyclic aryl; the nitrogen-containing heterocyclic ring is monocyclic or fused non-aromatic ring containing cyclic nitrogen atom, and a cyclic carbon atom is optionally replaced by oxygen; the nitrogen-containing heteroaromatic ring is monocyclic or fused polycyclic heteroaromatic ring containing cyclic nitrogen atom, and a cyclic carbon atom is optionally replaced by oxygen.

8. The method according to claim 7, wherein a preparation method of a catalyst precursor is loading a M.sub.a metal precursor, a M.sub.b precursor and a M.sub.c precursor on the support to form the catalyst precursor, the M.sub.a metal precursor is soluble inorganic salt, organic salt or metal complex of M.sub.a metal in a solvent, alternatively the M.sub.a metal precursor is nitrate, chloride, sulphate, acetate, acetylacetone salt, complex; the M.sub.b or M.sub.c metal precursors is soluble organic or inorganic salt of M.sub.b or M.sub.c in a solvent, alternatively the M.sub.b and M.sub.c metal precursor is nitrate, chloride, sulphate, acetate, oxalate, acetylacetone salt; the solvent is water or alcohol, wherein the alcohol is methanol or ethanol.

9. The method according to claim 8, wherein the preparation method of the catalyst precursor comprises, optionally, aging at the range of room temperature to 80? C., the aging time is 0.5-40 h, or 2-8 h, optionally, after aging, drying at 60-150? C., or 80-120? C., the drying time is 2-20 h, or 6-10 h; calcining the dried catalyst at 400-600? C. the calcining time is 3-6 h, to obtain the catalyst precursor.

10. The method according to claim 7, wherein the ammonia is ammonia gas, the nitrogen-containing organic is alternatively ethylenediamine, triethylamine, butylamine, aniline or dimethyl formamide.

11. The method according claim 7, wherein the treating is performed by using gaseous ethylenediamine at 300-600? C., the gaseous ethylenediamine is optionally the mixture of ethylenediamine and nitrogen in a volume ratio of 1-5:20-24, the treating time is 0.05-4 h, or 0.5-1.5 h.

12. The method according to claim 7, wherein the catalyst is Ir/Zn/K@Al.sub.2O.sub.3, Ir/Sn/K@Al.sub.2O.sub.3, Ir/Zn/Na@Al.sub.2O.sub.3, Ir/Sn/Na@Al.sub.2O.sub.3, wherein the content of Ir is 0.1-2 wt % based on catalyst weight, the content of Zn or Sn is 0.1-3.0 wt % based on catalyst weight, and the content of K or Na is 0.1-2.0 wt % based on catalyst weight.

13. A regeneration method of metal supported catalyst, the metal supported catalyst is a M.sub.a-M.sub.b-M.sub.c metal supported catalyst, wherein the metal supported catalyst does not contain M.sub.c metal, the method comprising: step A, removing the substances which cause the metal supported catalyst poisoned or deactivated to regenerate the metal supported catalyst; step B, treating the catalyst obtained from step A by ammonia or a nitrogen-containing organic at 10-700? C. to obtain an activated catalyst; in the step A, the substances which cause the catalyst deactivated comprise coke and/or sulfur; the removing process comprises: oxidation removing by O.sub.2, oxidation removing by air, or reduction removing by H.sub.2; wherein M.sub.a metal is an active metal which is selected from one or more of noble metal and transition metal, wherein the noble metal is selected from one or more mixtures of Pt, Au, Ru, Rh, Pd, Ir and Ag, the transition metal is selected from La, Fe, Co, Mn, Cr, Ni or Cu; alternatively, the active metal is Pt, Ru, Pd, Ir, Cr, Ni, PtPd, IrPt, IrPd, or IrPtPd; M.sub.b metal is selected from one or more combinations of Zn, Co and Al, alternatively M.sub.b metal is Zn, Co or ZnCo mixed metal; the support is selected from alumina, silica-alumina, zirconia, cerium oxide, titanium oxide, or molecular sieve or the mixture thereof; alternatively the support is ?-alumina, titanium oxide, silica or NaY molecular sieve; the M.sub.a metal is loaded on the support in a state of single-atom sites, or in a state of coexistence of single-atom sites with clusters and/or nanoparticles; alternatively, the M.sub.a metal is loaded on the support in the state of single-atom sites, or in the state of coexistence of single-atom sites and clusters, or in the state of coexistence of single-atom sites, clusters and nanoparticles; the content of M.sub.a is 0.01-5 wt %, or 0.05-2 wt % based on catalyst weight; the content of M.sub.b is 0.1-20 wt %, 0.1-10 wt %, or 0.5-4 wt % based on catalyst weight; the nitrogen-containing organic is selected from C.sub.1-6 alkyl amines, C.sub.2-6 alkenyl amine, C.sub.6-20 aryl amine, C.sub.4-20 cyclic alkyl amine, C.sub.4-20 nitrogen-containing heterocyclic ring, C.sub.4-20 nitrogen-containing heteroaromatic ring and (RCO).sub.xNR.sub.3-x, wherein R is H or C.sub.1-6 alkyl, x is 1 or 2; the amine is a monamine or polyamine; optionally, the alkyl, alkenyl, aryl, nitrogen-containing heterocycle ring, and nitrogen-containing heteroaromatic ring are independently further substituted by oxygen, carbonyl, carboxyl, ester group, or amino group; the aryl is monocyclic aryl or fused polycyclic aryl; the nitrogen-containing heterocyclic ring is a monocyclic or fused non-aromatic ring containing cyclic nitrogen atom, and a cyclic carbon atom is optionally replaced by oxygen; the nitrogen-containing heteroaromatic ring is a monocyclic or fused polycyclic heteroaromatic ring containing cyclic nitrogen atom, and a cyclic carbon is optionally replaced by oxygen; alternatively, the nitrogen-containing organic is C.sub.1-6 alkyl amine, C.sub.1-6 alkyl diamine, C.sub.6-20 aryl amine, dimethyl formamide.

14. The regeneration method according to claim 13, wherein M.sub.a is one or more mixtures of Pt, Ru, Ir and Au: M.sub.b is Zn; the support is alternatively alumina; the nitrogen-containing organic is ethylenediamine, triethylamine, butylamine, aniline or dimethyl formamide.

15. A regeneration method of M.sub.a-M.sub.b-M.sub.c metal supported catalyst, comprising: step A, removing substances which cause the M.sub.a-M.sub.b-M.sub.c metal supported catalyst to be poisoned or deactivated to regenerate the catalyst; step B, treating the catalyst with ammonia or nitrogen-containing organic in the range of room temperature to 700? C. to obtain an activated catalyst; wherein M.sub.a is Ir, M.sub.b is selected from Zn, Sn and the mixture of both, M.sub.c is selected from K, Na or the mixture of both, the content of M.sub.a is 0.1-2 wt % based on catalyst weight, the content of the M.sub.b is 0.1-3.0 wt % based on catalyst weight, the content of the M.sub.c is 0.1-2.0 wt % based on catalyst weight, a support of the M.sub.a-M.sub.b-M.sub.c metal supported catalyst is alumina, or shaped alumina support; the M.sub.a metal is dispersed and loaded on the support in a state of single-atom sites, clusters or nanoparticles; alternatively M.sub.a metal is dispersed and loaded on the support in the state of single-atom sites, or in the state of coexistence of single-atom sites with clusters and/or nanoparticles; in the step A, the substances which cause the M.sub.a-M.sub.b-M.sub.c metal supported catalyst poisoned or deactivated comprise coke and/or sulfur; the removing process comprises: oxidation removing by O.sub.2, oxidation removing by air, or reduction removing by H.sub.2; in the step B, treating the catalyst by ammonia or nitrogen-containing organic, wherein the nitrogen-containing organic is optionally selected from ethylenediamine, triethylamine, butylamine, aniline and dimethyl formamide, the treatment temperature is optionally 300-700? C.

16. The regeneration method according to claim 15, wherein in the step B, in the range of 400-600? C., treating the catalyst by gaseous ethylenediamine, or by the mixture of ethylenediamine and nitrogen in a volume ratio of 1-5:20-24.

17. (canceled)

18. A method for preparing light olefin by the dehydrogenation of light alkane, comprising: using a catalyst to catalyze the dehydrogenation of C.sub.2-6 alkane to obtain C.sub.2-6 olefin, wherein the catalyst is obtained by the method according to claim 1.

19. A method for preparing light olefin by the dehydrogenation of light alkane, comprising: using a catalyst to catalyze the dehydrogenation of C.sub.2-6 alkane to obtain C.sub.2-6 olefin, wherein the catalyst is obtained by the regeneration method according to claim 13.

20. A method for preparing light olefin by the dehydrogenation of light alkane, comprising: using a catalyst to catalyze the dehydrogenation of C.sub.2-6 alkane to obtain C.sub.2-6 olefin, wherein the catalyst is obtained by the regeneration method according to claim 15.

Description

DESCRIPTION OF PICTURES

[0056] FIG. 1 shows aberration-corrected scanning transmission electron microscopy images of the fresh catalyst, in which (a) shows the metal in the single-atom sites state (part of it is cycled by dashed line), (b) shows the existence of clusters or nanoparticles of metal in the catalyst.

[0057] FIG. 2 shows aberration-corrected scanning transmission electron microscopy images of the catalyst regenerated for 50 times, in which (a) shows the metal in the single-atom sites state (part of it is cycled by dashed line); (b) shows the existence of clusters or nanoparticles of metal in the catalyst.

EXAMPLES

[0058] The terms and explanations for the Examples are as follows: [0059] concentration of metal precursor: the concentration is calculated by the mass of the metal element. For example, aqueous solution of Pd with concentration of 0.02 g/g represents the amount of the Pd element is 0.02 g in 1 g of solution [0060] microreactor: fixed-bed microreactor or microreactor device. [0061] microreactor tail gas: the tail gas generated after reaction in fixed-bed microreactor or microreaction device. [0062] min: minute. [0063] wt %: mass percent [0064] TEM: transmission electron microscope. [0065] HR-TEM: high-resolution transmission electron microscope. [0066] AC-STEM: aberration-corrected scanning transmission electron microscopy.

[0067] The technology of the present invention will be further described below by dehydrogenation of propane.

Preparation Example 1: Preparation of Active Metal/Zinc Supported Catalyst

[0068] 1.1 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/Al.sub.2O.sub.3

[0069] 0.5 g of IrC.sub.3.Math.3H.sub.2O and 0.5 g of NaCl were weighed, completely dissolved in 19 g of water at 80? C. 16.4 g of Zn(NO.sub.3).sub.2.Math.6H.sub.2O was dissolved in 7.4 g of the solution above.

[0070] After dissolving, the volume of the solution was diluted to the saturation impregnation volume of small spheres. The above solution was impregnated in 96.9 g of alumina spheres with equal volume, and dried at 120? C. overnight. Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) was obtained, which was marked as Ir.sub.(0.1 wt %) Zn.sub.(3 wt %)/Al.sub.2O.sub.3.

Ir.sub.(0.3 wt %)Zn.sub.(3 wt %)/Al.sub.2O.sub.3

[0071] 8.25 g of Zn(NO.sub.3).sub.2.Math.6H.sub.2O was dissolved in water, the volume of the solution was diluted to the saturation impregnation volume of alumina spheres. The solution above was impregnated in 50 g of alumina spheres with equal volume, aged at room temperature for 6 h and further dried overnight at 120? C., and then calcined at 600? C. for 4 h to obtain a sample. 0.5 g of IrCl.sub.3.Math.3H.sub.2O and 0.5 g of NaCl were weighed, completely dissolved in 19 g of water at 80? C. The volume of 2.2 g of the solution above was further diluted to the saturation impregnation volume of the sample 10 g of the sample was impregnated in the solution above with equal volume, dried overnight at 120? C., then calcined at 400? C. for 1 h, to obtain Ir/Zn catalyst (Ir 0.3 wt %; Zn 3 wt %) which was marked as Ir.sub.(0.3 wt %)Zn.sub.(3 wt %)/Al.sub.2O.sub.3.

1.2 Pt.sub.(0.3 wt %)Zn.sub.(1 wt %)/Al.sub.2O.sub.3

[0072] Chloroplatinic acid (containing 0.015 g of Pt) and zinc nitrate (containing 0.05 g of Zn) were weighed and dissolved in water, and the volume of the solution was diluted to 2.21 mL of saturation impregnation volume of alumina spheres. 5 g of alumina spheres were weighed and the solution above was impregnated in the alumina spheres, dried for 8 h at 80? C., calcined at 600? C. for 4 h, to obtain Pt/Zn catalyst (Pt 0.3 wt %, Zn 1 wt %), which was marked as Pt.sub.(0.3 wt %)Zn.sub.(1 wt %)/Al.sub.2O.sub.3.

1.3 CrZn/Al.sub.2O.sub.3 (200713a)

[0073] Preparation of 100 g of Cr and Zn supported alumina catalyst with loading amount of 0.5 wt % of Cr and 1.5 wt % of Zn: 3.85 g of chromium nitrate nonahydrate and 6.82 g of zinc nitrate hexahydrate were taken and dissolved in ethanol, diluted to 83.3 g, then 98 g of alumina was added, and a rotary evaporation was carried out at 40? C. After ethanol was completely evaporated and chromium and zinc species were fully loaded on the surface of alumina, the CrZn supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as Cr.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3.

1.4 MnZn/Al.sub.2O.sub.3 (d200829a)

[0074] Preparation of 100 g of Mn and Zn supported alumina catalyst with loading amount of 0.5 wt % of Mn and 1.5 wt % of Zn: 1.80 g of manganese nitrate tetrahydrate and 6.82 g of zinc nitrate hexahydrate were taken and dissolved in ethanol, diluted to 91.9 g, then 98 g of alumina was added, and a rotary evaporation was carried out at 40? C. After ethanol was completely evaporated and manganese and zinc species were fully loaded on the surface of alumina, the MnZn supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as Mn.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3.

1.5 FeZn/Al.sub.2O.sub.3 (200713b)

[0075] Preparation of 100 g of Fe and Zn supported alumina catalyst with loading amount of 0.5 wt % of Fe and 1.5 wt % of Zn: 3.62 g of ferric nitrate nonahydrate and 6.82 g of zinc nitrate hexahydrate were taken and dissolved in ethanol, diluted to 83.3 g, then 98 g of alumina was added, and a rotary evaporation was carried out at 40? C. After ethanol was completely evaporated and iron and zinc species were fully loaded on the surface of alumina, the FeZn supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as Fe.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3.

1.6 CoZn/Al.sub.2O.sub.3 (200918a)

[0076] Preparation of 100 g of Co and Zn supported alumina catalyst with loading amount of 0.5 wt % of Co and 1.5 wt % of Zn: 2.47 g of cobalt nitrate hexahydrate and 6.82 g of zinc nitrate hexahydrate were taken and dissolved in ethanol, diluted to 83.3 g, then 98 g of alumina was added, and a rotary evaporation was carried out at 40? C. After ethanol was completely evaporated and cobalt and zinc species were fully loaded on the surface of alumina, the CoZn supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as Co.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3.

1.7 NiZn/Al.sub.2O.sub.3 (200918b)

[0077] Preparation of 100 g of Ni and Zn supported alumina catalyst with loading amount of 0.5 wt % of Ni and 1.5 wt % of Zn: 2.48 g of nickel nitrate hexahydrate and 6.82 g of zinc nitrate hexahydrate were taken and dissolved in ethanol, diluted to 83.3 g, then 98 g of alumina was added, and a rotary evaporation was carried out at 40? C. After ethanol was completely evaporated and nickel and zinc species were fully loaded on the surface of alumina, the NiZn supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as Ni.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3.

1.8 CuZn/Al.sub.2O.sub.3 (d200730)

[0078] Preparation of 100 g of Cu and Zn supported alumina catalyst with loading amount of 0.5 wt % of Cu and 1.5 wt % of Zn: 1.90 g of copper nitrate trihydrate and 6.82 g of zinc nitrate hexahydrate were taken and dissolved in ethanol, diluted to 92.0 g, then 98 g of alumina was added, and a rotary evaporation was carried out at 40? C. After ethanol was completely evaporated and copper and zinc species were fully loaded on the surface of alumina, the CuZn supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as Cu.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3.

1.9 LaZn/Al.sub.2O.sub.3 (d200829b)

[0079] Preparation of 100 g of La and Zn supported alumina catalyst with loading amount of 0.5 wt % of La and 1.5 wt % of Zn: 1.34 g of lanthanum nitrate heptahydrate and 6.82 g of zinc nitrate hexahydrate were taken and dissolved in ethanol, diluted to 91.4 g, then 98 g of alumina was added, and a rotary evaporation was carried out at 40? C. After ethanol was completely evaporated and lanthanum and zinc species were fully loaded on the surface of alumina, the LaZn supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as La.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3.

1.10 Ir.sub.(0.1 wt %)Co.sub.(0.5 wt %)Zn.sub.(1 wt %)/Al.sub.2O.sub.3 (200608b)

[0080] 0.37 g of IrCl.sub.3.Math.3H.sub.2O and 0.36 g of NaCl were dissolved in water under heating condition and further diluted to 40.0 g with water in advance to obtain an aqueous solution with an Ir concentration of 0.005 g/g. 1.0 g of the aqueous solution was taken, then 0.11 g of cobalt nitrate hexahydrate and 0.23 g of zinc nitrate hexahydrate were added into the solution. The mixture was dissolved in ultrapure water and diluted to 2.2 g, then 4.9 g of alumina spheres was added for equal volume impregnation, then dried overnight at 120? C., the IrCoZn supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as Ir.sub.(0.1 wt %)Co.sub.(0.5 wt %)Zn.sub.(1 wt %)/Al.sub.2O.sub.3.

1.11 Ir.sub.(0.1 wt %)Co.sub.(0.75 wt %)Zn.sub.(0.75 wt %)/Al.sub.2O.sub.3 (200608c)

[0081] 0.37 g of IrCl.sub.3.Math.3H.sub.2O and 0.36 g of NaCl were dissolved in water under heating condition and further diluted to 40.0 g with water in advance to obtain an aqueous solution with an Ir concentration of 0.005 g/g. 1.0 g of the aqueous solution was taken, then 0.17 g of cobalt nitrate hexahydrate and 0.17 g of zinc nitrate hexahydrate were added into the solution. The mixture was dissolved in ultrapure water and further diluted to 2.2 g, then 4.9 g of alumina spheres was added for equal volume impregnation, then dried overnight at 120? C., the IrCoZn supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as Ir.sub.(0.1 wt %)Co.sub.(0.75 wt %)Zn.sub.(0.75 wt %)/Al.sub.2O.sub.3.

1.12 Ir.sub.(0.1 wt %)Co.sub.(1.5 wt %)/Al.sub.2O.sub.3 (200611d)

[0082] 0.37 g of IrCl.sub.3.Math.3H.sub.2O and 0.36 g of NaCl were dissolved in water under heating condition and further diluted to 40.0 g with water in advance to obtain an aqueous solution with an Ir concentration of 0.005 g/g. 1.0 g of the aqueous solution was taken, then 0.33 g of cobalt nitrate hexahydrate was added into the solution. The mixture was dissolved in ultrapure water and further diluted to 2.2 g, then 4.9 g of alumina spheres was added for equal volume impregnation, then dried overnight at 120? C., the IrCo supported Al.sub.2O.sub.3 catalyst was obtained, which was marked as Ir.sub.(0.1 wt %)Co.sub.(1.5 wt %)/Al.sub.2O.sub.3.

1.13 The catalyst was prepared, which was marked as Ir.sub.(0.1 wt %)Zn.sub.(1.5 wt %)Al.sub.(1.24 wt %)/Al.sub.2O.sub.3
1.14 The catalyst was prepared, which was marked as Ir.sub.(0.15 wt %)Zn.sub.(1.5 wt %)Al.sub.(1.24 wt %)/Al.sub.2O.sub.3
1.15 Ir.sub.(0.1 wt %)Zn.sub.(1 wt %)/NaY molecular sieve

[0083] 5 g of NaY molecular sieve pellets were weighed, then over-volume impregnated in an aqueous solution containing 0.26% of IrCl.sub.3 and 7.8% of Zn(NO.sub.3).sub.2 for 30 min. After solid-liquid separation, the solid was dried overnight at 120? C. to obtain the Ir/Zn catalyst (Ir 0.15 wt %; Zn 1.5 wt %).

1.16 Ir.sub.(0.3 wt %)Zn.sub.(3 wt %)/SiO.sub.2

[0084] 0.5 g of IrCl.sub.3.Math.3H.sub.2O and 0.5 g of NaCl were weighed and completely dissolved in 19 g of water at 80? C. 0.8 g of Zn(NO.sub.3).sub.2.Math.6H.sub.2O was dissolved in 1.1 g of the solution above, then the volume of the obtained solution was diluted to the saturation impregnation volume of silica pellets. The above solution was impregnated in 5 g of silica pellets with equal volume, and further dried overnight at 120? C., to obtain Ir/Zn catalyst (Ir 0.3 wt %; Zn 3 wt %).

Preparation Example 2: Pretreatment Method for the Regeneration of Catalyst

[0085] Catalyst was regenerated in this experiment, the catalyst to be treated was calcined at 400-450? C. for 3 h in air atmosphere with a flow of 49.8 mL/min to remove coke, and a regenerated catalyst was obtained.

Application Test Example 3: Experimental Method for Dehydrogenation of Alkane

[0086] This invention takes the dehydrogenation of propane to prepare propylene as an example.

[0087] The catalytic performance of catalyst was evaluated with continuous flow fixed bed reactor, in which 1.0 g of catalyst was loaded in a straight quartz reaction tube with an inner diameter of 10 mm.

[0088] The catalyst was treated or activated

[0089] The reaction temperature of 600? C. was controlled by a tubular resistance furnace.

[0090] The flow rate of reaction gas was controlled by mass flow meter. Before and after reaction, the reaction tube was purged with nitrogen or other inert gas.

[0091] The reaction product was analyzed by Shimadzu gas chromatograph equipped with an HP-PLOT Al.sub.2O.sub.3S capillary column.

Example 1

[0092] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %, Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 500? C. under 100% ammonia gas atmosphere for 30 min. Pure propane gas (volume space velocity. 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Examples 2 to 11

[0093] Referring to the experimental operations in Example 1, N.sub.2 was used as diluent gas to adjust the concentration of ammonia, treatment temperature, treatment time were adjusted, the other operations were the same as those in Example 1. The specific adjustments are shown as follow:

[0094] In Example 2, the ammonia concentration was 80% (N.sub.2 2.6 mL/min, NH.sub.3 10.5 mL/min), treatment temperature was 500? C., and treatment time was 30 min;

[0095] In Example 3, the ammonia concentration was 50% (N.sub.2 6.55 ml/min, NH.sub.3 6.55 mL/min), treatment temperature was 500? C., and treatment time was 30 min.

[0096] In Example 4, the ammonia concentration was 20% (N.sub.2 10.5 mL/min, NH.sub.3 2.6 mL/min), treatment temperature was 500? C., and treatment time was 30 min.

[0097] In Example 5, the ammonia concentration was 3% (N.sub.2 12.7 mL/min, NH.sub.3 0.4 mL/min), treatment temperature was 500? C., and treatment time was 30 min.

[0098] In Example 6, the ammonia concentration was 3% (N.sub.2 12.7 mL/min, NH.sub.3 0.4 mL/min), treatment temperature was 500? C., and treatment time was 15 min.

[0099] In Example 7, the ammonia concentration was 3% (N.sub.2 12.7 mL/min, NH.sub.3 0.4 mL/min), treatment temperature was 500? C., and treatment time was 30 min.

[0100] In Example 8, the ammonia concentration was 3% (N.sub.2 12.7 mL/min, NH.sub.3 0.4 mL/min), treatment temperature was 500? C., and treatment time was 45 min.

[0101] In Example 9, the ammonia concentration was 3% (N.sub.2 12.7 mL/min, NH.sub.3 0.4 mL/min), treatment temperature was 500? C., and treatment time was 75 min.

[0102] In Example 10, the ammonia concentration was 3% (N.sub.2 12.7 mL/min, NH.sub.3 0.4 ml/min), treatment temperature was 500? C., and treatment time was 120 min.

[0103] In Example 11, the ammonia concentration was 3% (N.sub.2 12.7 mL/min, NH.sub.3 0.4 mL/min), treatment temperature was 500? C., and treatment time was 150 min.

Example 12

[0104] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 500? C. under 2% ethylenediamine/nitrogen atmosphere for 15 min. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation of propane were evaluated.

Example 13

[0105] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 500? C. under 2% ethylenediamine/nitrogen atmosphere for 60 min. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation of propane were evaluated.

Example 14

[0106] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at room temperature (10? C.) under 4% ethylenediamine/nitrogen atmosphere for 30 min Pure propane gas (volume space velocity. 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Example 15

[0107] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 700? C. under 4% ethylenediamine/nitrogen atmosphere for 30 min. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Example 16

[0108] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 500? C. under 1% ethylenediamine/nitrogen atmosphere for 30 min. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Example 17

[0109] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 500? C. under 4% n-butylamine/nitrogen atmosphere for 30 min. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Example 18

[0110] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 500? C. under 4% triethylamine/nitrogen atmosphere for 30 min. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Example 19

[0111] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 500? C. under 4% aniline/nitrogen atmosphere for 30 min. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Example 20

[0112] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 500? C. under 4% DMF/nitrogen atmosphere for 30 min. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Example 21

[0113] 1 g of the Pt/Zn catalyst (Pt 0.3 wt %; Zn 1 wt %) prepared by Preparation Example 1.2 was weighed, treated at 500? C. under 4% ethylenediamine/nitrogen atmosphere for 30 min. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Examples 22 to 35

[0114] Referring to a method similar to Example 1, the 1.3-1.16 metal supported catalysts prepared by Preparation Example 1 were weighed respectively, treated at 500? C. under 4% ethylenediamine/nitrogen atmosphere for 30 min respectively. Pure propane gas (volume space velocity: 1000 h.sup.?1) was introduced for reaction at 600? C., and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested.

Example 36 Regeneration Example

[0115] 1 g of the Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %) prepared by Preparation Example 1.1 was weighed, treated at 500? C. under 4% ethylenediamine/nitrogen atmosphere for 30 min. At 600? C. and under the condition of 0.25 of hydrogen to hydrocarbon ratio (hydrogen to propane ratio), propane was directly catalyzed for dehydrogenation reaction (propane volume space velocity: 1000 h.sup.?1), the measured conversion of propane was 40% and the selectivity for propylene was 92% After continuous testing for 6 h, the conversion of propane dropped to 33% and the selectivity for propylene was 93%.

[0116] The catalyst after the test above was calcined at 400? C. for 3 h under air atmosphere to remove coke, and the obtained regenerated sample was treated at 500? C. under 4% ethylenediamine/nitrogen atmosphere for 30 min.

[0117] At 600? C. and under the condition of 0.25 of hydrogen to propane ratio, propane was directly catalyzed for dehydrogenation reaction (propane volume space velocity: 1000 h.sup.?1), the measured conversion of propane was 39% and the selectivity for propylene was 93%.

Comparative Example 1

[0118] 1 g of Ir/Zn catalyst (Ir 0.1 wt %; Zn 3 wt %, alumina support) was weighed and not subjected to any treatment Pure propane gas was introduced for reaction at 600? C. and the conversion and selectivity of direct catalytic dehydrogenation reaction of propane were tested (volume space velocity: 1000 h.sup.?1).

Application Test and Results:

[0119]

TABLE-US-00001 TABLE 1 The treatment conditions and performance comparison of Examples 1 to 20 and Comparative Example 1. Treatment conditions Atmosphere Optimal performance Catalyst and Temperature Conversion Selectivity Example composition Concentration Time(min) (? C.) (%) (%) EX1 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 100% 30 500 30.1 89.07 Al.sub.2O.sub.3 ammonia gas EX 2 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 80% 30 500 31.85 89.638 Al.sub.2O.sub.3 ammonia gas EX3 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 50% 30 500 30 89 Al.sub.2O.sub.3 ammonia gas EX4 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 20% 30 500 32.41 89.88 Al.sub.2O.sub.3 ammonia gas EX5 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 3% 30 500 32.83 89.55 Al.sub.2O.sub.3 ammonia gas EX6 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 3% 15 500 32.45 89.33 Al.sub.2O.sub.3 ammonia gas EX7 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 3% 30 500 32.83 89.55 Al.sub.2O.sub.3 ammonia gas EX8 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 3% 45 500 33.65 89.78 Al.sub.2O.sub.3 ammonia gas EX9 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 3% 75 500 33 89.36 Al.sub.2O.sub.3 ammonia gas EX10 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 3% 120 500 31.95 89.45 Al.sub.2O.sub.3 ammonia gas EX11 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 3% 150 500 32.71 89.67 Al.sub.2O.sub.3 ammonia gas EX12 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 2% 15 500 30.1 89.07 Al.sub.2O.sub.3 ethylenediamine EX13 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 2% 60 500 31.85 89.638 Al.sub.2O.sub.3 ethylenediamine EX14 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 4% 30 10 30 89 Al.sub.2O.sub.3 ethylenediamine EX15 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 4% 30 700 32.41 89.88 Al.sub.2O.sub.3 ethylenediamine EX16 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 1% 30 500 32.83 89.55 Al.sub.2O.sub.3 ethylenediamine EX17 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 4% 30 500 32.45 89.33 Al.sub.2O.sub.3 n-butylamine EX18 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 4% 30 500 32.5 88.86 Al.sub.2O.sub.3 triethylamine EX19 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 4% aniline 30 500 33.65 89.78 Al.sub.2O.sub.3 EX20 Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 4% DMF 30 500 33 89.36 Al.sub.2O.sub.3 Comparative Ir.sub.(0.1 wt %)Zn.sub.(3 wt %)/ 18 84 Example 1 Al.sub.2O.sub.3 *EX1 represents Example1, and so on.

[0120] The test results of Examples 1 to 20 and Comparative Example 1 show that the treatment method of catalyst in the present invention, whether using NH.sub.3 or using nitrogen-containing organic, significantly improves the conversion and selectivity of the catalyst, which fully demonstrates the effectiveness of treatment with NH.sub.3 and nitrogen-containing organic.

TABLE-US-00002 TABLE 2 The treatment conditions and performance comparison of Examples 21 to 35. Treatment conditions Optimal Atmosphere performance and Time Temperature Conversion Selectivity Example Catalyst composition Concentration (min) (? C.) (%) (%) EX21 Pt.sub.(0.3 wt %)Zn.sub.(1 wt %)/Al.sub.2O.sub.3 4% 30 500 20.78 82.92 ethylenediamine EX22 Cr.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3 4% 30 500 23.1 84.9 (200713a) ethylenediamine EX23 Mn.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3 4% 30 500 14.2 82.2 (d200829a) ethylenediamine EX24 Fe.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3 4% 30 500 16 83.6 (200713b) ethylenediamine EX25 Co.sub.(0.5 wt %)Zn.sub.(1.5 wt%)/Al.sub.2O.sub.3 4% 30 500 19.9 84.6 (200918a) ethylenediamine EX26 Ni.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3 4% 30 500 21 71.3 (200918b) ethylenediamine EX27 Cu.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3 4% 30 500 15.9 82.2 (d200730) ethylenediamine EX28 La.sub.(0.5 wt %)Zn.sub.(1.5 wt %)/Al.sub.2O.sub.3 4% 30 500 14.1 82.6 (d200829b) ethylenediamine EX29 Ir.sub.(0.1 wt %)Co.sub.(0.5 wt %)Zn.sub.(1 wt %)/Al.sub.2O.sub.3 4% 36 500 41.288 92.0325 (200608b) ethylenediamine EX30 Ir.sub.(0.1 wt %)Co.sub.(0.75 wt %)Zn.sub.(0.7 wt %)/Al.sub.2O.sub.3 4% 30 500 38.656 92.22 (200608c) ethylenediamine EX31 Ir.sub.(0.1 wt %)Co.sub.(1.5 wt %)/Al.sub.2O.sub.3 4% 30 500 37.88 91.92 ethylenediamine EX32 Ir.sub.(0.1 wt %)Zn.sub.(1.5 wt %)Al.sub.(1.24 wt %)/Al.sub.2O.sub.3 4% 30 500 28.34 92.5 ethylenediamine EX33 Ir.sub.(0.15 wt %)Zn.sub.(1.5 wt %)Al.sub.(1.24 wt %)/Al.sub.2O.sub.3 4% 30 500 32.73 93.39 ethylenediamine EX34 Ir.sub.(0.15 wt %)Zn.sub.(1.5 wt %)/NaY 4% 30 500 16.06 67 ethylenediamine EX35 Ir.sub.(0.3 wt %)Zn.sub.(3 wt %)/SiO.sub.2 4% 30 500 13.26 76.72 ethylenediamine

[0121] The test results in Table 2 show that the catalysts prepared using Zn, Co or Al as promoter possess good catalytic activity for dehydrogenation of alkane, whether the active metal is noble metal or transition metal. The catalytic activity of noble metal is higher than that of transition metal

3 Regeneration of Catalyst

[0122] Example 36 reveals that the regeneration method of catalyst in this invention is simple and efficient. After regeneration, the catalytic performance of the catalyst does not obviously decrease Under the same test conditions (hydrogen to hydrocarbon ratio is 0.25), the conversion and selectivity of the regeneration catalyst were comparable to those of the fresh catalyst.

[0123] In fact, the inventors regenerated the catalyst for 50 times, and the resulting catalyst still has high conversion and high selectivity.

[0124] It should be noted that the test conditions used in Example 36 were slightly different from those in other examples, in which a certain proportion of hydrogen was mixed with propane gas to simulate the actual operating conditions of industrial production.

4 Structure Characterization of Catalysts.

[0125] The inventors characterized the structure of fresh catalyst without carbon and nitrogen (CN) treatment, where the catalyst consists of Ir.sub.(0.3 wt %)Zn.sub.(2 wt %)/Al.sub.2O.sub.3 and the characterization result was shown in FIG. 1. FIG. 1 aberration-corrected scanning transmission electron microscopy images of the fresh catalyst, in which, FIG. a shows the single-atom sites state of metal (part of it is cycled by dashed line) and FIG. b shows the existence of clusters or nanoparticles of metal in the catalyst. It can be seen that there are a large amount of metal dispersed in the single-atom sites state, as well as metal in clusters state even in nanoparticles state in the catalyst. However, the method of the present invention is effective for improving the conversion and selectivity of the above catalyst.

[0126] FIG. 2 shows Aberration-corrected Scanning Transmission Electron microscopy images of the catalyst regenerated by burning coke for 50 times. The catalyst composition is the same as that of FIG. 1. In FIG. 2, FIG. a shows the single-atom sites state of metal (part of it is cycled by dashed line) and FIG. b shows the existence of clusters or nanoparticles of metal in the catalyst. It is also revealed that the active metal also exists in three states of single-atom sites, clusters and nanoparticles in the catalyst after repeated regeneration, and the method of this invention is also effective.

Example 37

[0127] This example provided a single-atom catalyst for dehydrogenation of propane. The catalyst uses alumina spheres with diameter of 1-2 mm as support, Ir as active component, Sn as first promoter and K as second promoter. In the catalyst, the mass percentage content of Ir is 0.3%, the mass percentage content of the first promoter is 1.0%, and the percentage content of the second promoter is 1.0% The catalyst was prepared by isovolumetric impregnation method and treatment with ethylenediamine gas to load single atoms of Ir. The specific process was as follows: 5 g of alumina spheres (diameter of 1 mm to 2 mm, specific surface area of 220 m.sup.2/g, water absorption rate of 0.442) were weighed. 2.21 mL of mixed impregnation solution of H.sub.2IrCl.sub.6, SnCl.sub.4, HCl and KCl was prepared according to 0.3 wt % of active component Ir, 1.0 wt % of promoter Sn and 1.0 wt % of K based on the catalyst weight. The prepared solution was added dropwise into the alumina spheres. The mixture system was aged for 4 h, dried at 80? C. for 8 h, then calcined at 600? C. for 4 h, and then activated for 0.5 h using a mixture gas of ethylenediamine and nitrogen with a volume ratio of 1:24, cooled to room temperature naturally, to obtain the catalyst C-1.

Example 38

[0128] This example provided a single-atom catalyst for dehydrogenation of propane. The catalyst uses spherical alumina with diameter of 1-2 mm as support, Ir as active component, Zn as a first promoter and K as a second promoter. In the catalyst, the mass percentage content of Ir is 0.3%, the mass percentage content of the first promoter is 1.0%, and the percentage content of the second promoter is 1.0%. The catalyst was prepared by isovolumetric impregnation method and treatment with ethylenediamine gas to load Ir single atoms. The specific process was as follows 5 g of alumina spheres (diameter of 1 mm to 2 mm, specific surface area of 220 m.sup.2/g, water absorption rate of 0.442) were weighed. 2.21 mL of mixed impregnation solution of H.sub.2IrCl.sub.6, Zn(NO.sub.3).sub.2, HCl and KCl was prepared according to 0.3 wt % of active component Ir, 1.0 wt % of promoter Zn and 1.0 wt % of K based on the catalyst weight. The prepared solution was added dropwise into the alumina spheres. The mixture system was aged for 4 h, dried at 80? C. for 8 h, then calcined at 600? C. for 4 h, and then activated for 0.5 h using a mixture gas of ethylenediamine and nitrogen with a volume ratio of 1:24, cooled to room temperature naturally, to obtained the catalyst C-2.

Example 39

[0129] This example provided a single-atom catalyst for dehydrogenation of propane. The catalyst uses spherical alumina with diameter of 1-2 mm as support, Ir as active component, Sn as a first promoter and Na as a second promoter. In the catalyst, the mass percentage content of Ir is 0.3%, the mass percentage content of the first promoter is 1.0%, and the percentage content of the second promoter is 1.0%. The catalyst was prepared by isovolumetric impregnation method and treatment with ethylenediamine gas to load Ir single atoms. The specific process was as follows: 5 g of alumina spheres (diameter of 1 mm to 2 mm, specific surface area of 220 m.sup.2/g, water absorption rate of 0.442) were weighed. 2.21 mL of mixed impregnation solution of H.sub.2IrCl.sub.6, SnCl.sub.4, HCl and NaCl was prepared according to 0.3 wt % of active component Ir, 1.0 wt % of promoter Sn and 1.0 wt % of Na based on the catalyst weight. The prepared solution was added dropwise into the alumina spheres. The mixture system was aged for 4 h, dried at 80? C. for 8 h, then calcined at 600? C. for 4 h, and then activated for 0.5 h using a mixture gas of ethylenediamine and nitrogen with a volume ratio of 1:24, and cooled to room temperature naturally, to obtain the catalyst C-3.

Example 40

[0130] This example provided a single-atom catalyst for dehydrogenation of propane. The catalyst uses alumina spheres with diameter of 1-2 mm as support, Ir as active component, Zn as a first promoter and Na as a second promoter. In the catalyst, the mass percentage content of Ir is 0.3%, the mass percentage content of the first promoter is 1.0%, and the percentage content of the second promoter is 1.0%. The catalyst was prepared by isovolumetric impregnation method and treatment with ethylenediamine gas to load Ir single atoms. The specific process was as follows: 5 g of alumina spheres (diameter of 1 mm to 2 mm, specific surface area of 220 m.sup.2/g, water absorption rate of 0.442) were weighed 2.21 mL of mixed impregnation solution of H.sub.2IrCl.sub.6, Zn(NO.sub.3).sub.2, HCl and NaCl was prepared according to 0.3 wt % of active component Ir, 1.0 wt % of promoter Zn and 1.0 wt % of Na based on the catalyst weight. The prepared solution was added dropwise into the alumina spheres. The mixture system was aged for 4 h, dried at 80? C. for 8 h, then calcined at 600? C. for 4 h, and then activated for 0.5 h using a mixture gas of ethylenediamine and nitrogen with a volume ratio of 1:24, cooled to room temperature naturally, to obtain the catalyst C-4.

Comparative Example 2

[0131] This comparative example provided a catalyst for dehydrogenation of propane. The catalyst uses alumina spheres with diameter of 1-2 mm as support and Ir as active component, without any other promotor. The mass percentage content of Ir in the catalyst is 0.3%. The catalyst was prepared by isovolumetric impregnation method. The specific process was as follows: 5 g of alumina spheres (diameter of 1 mm to 2 mm, specific surface area of 220 m.sup.2/g, water absorption rate of 0.442) were weighed. 2.21 mL of impregnation solution of H.sub.2IrCl.sub.6 and HCl was prepared according to 0.3 wt % of active component Ir based on the catalyst weight. The prepared solution was added dropwise into the alumina spheres. The mixture system was aged for 4 h, dried at 80? C. for 8 h, then calcined at 600? C. for 4 h, and then activated for 0.5 h using a mixture gas of ethylenediamine and nitrogen with a volume ratio of 1:24, then cooled to room temperature naturally, to obtain the catalyst D-1.

Comparative Example 3

[0132] This comparative example provided a catalyst for dehydrogenation of propane. The catalyst uses alumina spheres with diameter of 1-2 mm as support, Ir as active component and Sn as promoter. In the catalyst, the mass percentage content of Ir is 0.3% and the mass percentage content of Sn is 1.0% The catalyst was prepared by isovolumetric impregnation method. The specific process was as follows: 5 g of alumina spheres (diameter of 1 mm to 2 mm, specific surface area of 220 m.sup.2/g, water absorption rate of 0.442) were weighed. 2.21 mL of impregnation solution of H.sub.2IrCl.sub.6, SnCl.sub.4 and HCl was prepared according to 0.3 wt % of active component Ir and 1.0 wt % of promoter Sn based on the catalyst weight. The prepared solution was added dropwise into the alumina spheres. The mixture system was aged for 4 h, dried at 80? C. for 8 h, then calcined at 600? C. for 4 h., and then activated for 0.5 h using a mixture gas of ethylenediamine and nitrogen with a volume ratio of 1:24, then cooled to room temperature naturally, to obtain the catalyst D-2.

Comparative Example 4

[0133] This comparative example provided a catalyst for dehydrogenation of propane. The catalyst uses alumina spheres with diameter of 1-2 mm as support, Ir as active component and Zn as promoter. In the catalyst, the mass percentage content of Ir is 0.3% and the mass percentage content of Zn is 1.0%. The catalyst was prepared by isovolumetric impregnation method. The specific process was as follows: 5 g of alumina spheres (diameter of 1 mm to 2 mm, specific surface area of 220 m.sup.2/g, water absorption rate of 0.442) were weighed. 2.21 mL of impregnation solution of H.sub.2IrCl.sub.6. Zn(NO.sub.3).sub.2 and HCl was prepared according to 0.3 wt % of active component Ir and 1.0 wt % of promoter Zn based on the catalyst weight. The prepared solution was added dropwise into the alumina spheres. The mixture system was aged for 4 h, dried at 80? C. for 8 h, then calcined at 600? C. for 4 h, and then activated for 0.5 h using a mixture gas of ethylenediamine and nitrogen with a volume ratio of 1:24, then cooled to room temperature naturally, to obtain the catalyst D-3.

Regeneration Example 41

[0134] The deactivated catalyst of example 37-4 after reaction was calcined at 400? C. for 3 h under air atmosphere to remove coke. Then the obtained regenerated sample was treated at 500? C. for 30 min under an atmosphere of the mixture gas of ethylenediamine and nitrogen with a volume ratio of 1:24.

[0135] The regenerated catalyst was evaluated by dehydrogenation of propane to propylene. It is found that compared with a fresh catalyst, the regenerated catalyst possesses similar conversion and selectivity

Method for Catalytic Activity Test and the Test Result

[0136] The catalysts of examples 37-40 and comparative examples 2-4 of this invention were used to catalyze the dehydrogenation of propane to propylene, the specific method was as follows: 1.0 g of catalyst was placed in a fixed bed reactor for the dehydrogenation of propane to propylene; under normal pressure condition, nitrogen was introduced to the reaction system at a flow rate of 13.1 mL/min; and the temperature of the reaction system was raised from room temperature to 600? C. at a rate of 3? C./min. Then a mixture gas of hydrogen and propane with a volume ratio of 1:2 was introduced to the reaction system at a total flow rate of 39.3 mL/min, to dehydrogenate propane to propylene under normal pressure. The catalytic performances of the catalysts of examples 37-40 and comparative examples 2-4 in this invention for dehydrogenation of propane to propylene are shown in Table 3.

TABLE-US-00003 TABLE 3 Catalytic performances of the catalysts of examples 37-40 and comparative examples 2-4 for dehydrogenation of propane to propylene Active components Catalytic performances of catalyst Conver- Selec- Conver- Selec- (based on alumina sion tivity sion tivity catalyst support) (1 h) (1 h) (2 h) (2 h) C-1 Ir0.3% Sn1% K1% 33.99% 94.88% 34.16% 94.60% C-2 Ir0.3% Zn1% K1% 35.69% 94.59% 35.74% 94.54% C-3 Ir0.3% Sn1% Na1% 35.31% 94.45% 34.92% 94.30% C-4 Ir0.3% Zn1% Na1% 33.56% 94.03% 33.42% 93.86% D-1 Ir0.3% 27.82% 93.21% 27.13% 93.02% D-2 Ir0.3% Sn1% 33.51% 93.11% 29.62% 92.87% D-3 Ir0.3% Zn1% 33.04% 92.90% 33.31% 93.10%

[0137] The Table 3 shows that the addition of the first promoter and/or the second promoter improves the conversion and selectivity of the catalyst obviously. In addition, the performance data of 2 h reveals that the catalyst of this invention exhibits a better stability.

[0138] The above examples only clearly illustrate the present invention, but are not to be construed as limiting the present invention. To common technician of related field, other different forms of variations or adjustments can be further made on the basis of the illustration above. It is impossible to exhaustively describe all the possible situation here, but the obvious variations or adjustments extended from the technical solution of the present invention are still within the protection scope of this invention.