Process for the catalytic preparation of hydrogen cyanide from methane and ammonia

Abstract

The invention relates to a catalyst material comprising a support, a first metal and a second metal on said support. The first and second metals are in the form of a chemical compound. The first metal is Fe, Co or Ni, and the second metal is selected from the group consisting of Sn, Zn and In. The invention also relates to a process for the preparation of hydrogen cyanide (HCN) from methane (CH.sub.4) and ammonia (NH.sub.3), wherein the methane and ammonia are contacted with a catalyst according to the invention.

Claims

1. A process for the preparation of hydrogen cyanide (HCN) from methane (CH.sub.4) and ammonia (NH.sub.3), wherein the methane and ammonia are contacted with a catalyst material comprising a support, a first metal and a second metal on said support, wherein said first and second metal are in the form of an alloy, where said first metal is Fe, Co or Ni, and where said second metal is selected from the group consisting of Sn, Zn and In, and the temperature of the process is between 850 C. and 1000 C.

2. A process according to claim 1, wherein the temperature of the process is between 850 C. and 950 C.

3. A process according to claim 1, wherein the support is a ferromagnetic support used as an inductive heating element in the process.

4. A process according to claim 1, wherein the support comprises an alumina, a spinet of alumina, an oxide, a carbide, a nitride, or a carbonitride.

5. A process for the preparation of hydrogen cyanide (HCN) from methane (CH.sub.4) and ammonia (NH.sub.3), wherein the methane and ammonia said support, wherein the first and second metal form a ternary compound with carbon or nitrogen, where said first metal is Fe, Co or Ni, and where said second metal is selected from and 1000 C.

6. A process according to claim 1, wherein the first metal comprises Co.

7. A process according to claim 1, wherein the first metal comprises Co and the second metal comprises Sn.

8. A process according to claim 1, wherein the ratio of the weight percent of Fe, Co or Ni to Sn, Zn or In is between 5:1 and 1:5.

9. A process according to claim 1, wherein the ratio of the weight percent of Fe, Co or Ni to Sn, Zn or In is 1:2.4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is CoSn phase diagram, and

(2) FIGS. 2a-2d are XRD plots of spent catalysts according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(3) FIG. 1 is CoSn phase diagram as seen in FIG. 1, page 370, of Landolt-Brnstein, Numerical Data and Functional Relationships in Science and Technology, Group IV: Macroscopic Properties of Matter, Volume 5, Phase Equilibria, Crystallographic and Thermodynamic Data of Binary Alloys, Subvolume c, CaCd . . . CoZr, B. Predel. FIG. 1 shows phase equilibria for Cobalt (Co) and Tin (Sn) for temperatures between 400 and 2000 K; moreover, the Curie temperature T.sub.c is indicated. FIG. 1 is thus an alloy diagram showing the presence of different phases of Sn and Co. A CoSn alloy may contain one or more of these discrete or distinct phases. Such a discrete phase (or a mixture of discrete phases) is also denoted a chemical compound.

(4) FIGS. 2a-2d are XRD plots of spent catalysts according to the invention.

(5) In FIG. 2a, the main phase is eta/gamma-Al.sub.2O.sub.3 giving a high background. The crystalline phases are Co.sub.3Sn.sub.2.

(6) In FIG. 2b, the main phase is eta/gamma-Al.sub.2O.sub.3 and amorphous carbon, giving a high background. The crystalline phases are Co.sub.3Sn.sub.2, gamma-Co.sub.1.5Sn, CoSn, beta-CoSn.sub.3, CoSn.sub.2.

(7) In FIG. 2c, the main phase is eta/gamma-Al.sub.2O.sub.3 and some amorphous carbon, giving a high background. The crystalline phases are Co.sub.3Sn.sub.2, gamma-Co.sub.1.5Sn, CoSn, CoSn.sub.2, some Co.sub.3SnC.

(8) In FIG. 2d, the main phase is eta/gamma-Al.sub.2O.sub.3 and amorphous carbon, giving a high background. The crystalline phases are Co.sub.3Sn.sub.2, gamma-Co.sub.1.5Sn, CoSn, CoSn.sub.2, some Co.sub.3SnC.

(9) For all four FIGS. 2a-2d, the following reference code table applies:

(10) TABLE-US-00001 Ref. Code Compound Name Chemical Formula A Aluminum Oxide Al.sub.2.67O.sub.4 B Cobalt Tin CoSn C Cobalt Tin Co.sub.3Sn.sub.2 D Cobalt Tin CoSn E Cobalt Tin Co.sub.1.5Sn F Cobalt Tin CoSn.sub.3 G Cobalt Tin CoSn.sub.2 H Cobalt Tin Co.sub.2.9Sn.sub.2 I Cobalt Tin Co.sub.0.75Sn.sub.0.25 J Cobalt Tin Co.sub.1.5Sn K Cobalt Tin CoSn L Cobalt Tin Carbide Co.sub.3SnC

(11) The compounds denoted B, D and K in the reference code table belong to the same space group (P6/mmm, 191), having hexagonal lattice geometry. However, the lattice constants of the compound denoted B, D and K are slightly different:

(12) B: a=b=5.318 , c=4.281

(13) D: a=b=5.234 , c=4.166

(14) K: a=b=5.224 , c=4.207

(15) For FIG. 2a, the following correspondence table for the XRD plot applies:

(16) TABLE-US-00002 No. Pos. [2Th.] Matched by 1 21.3129 D; F 2 28.8912 D 3 30.7076 C; E 4 33.0482 F; G 5 34.1929 C; D 6 35.8144 F; G 7 36.7855 F 8 39.6646 A; B; C; D; 9 40.4455 D; F 10 41.4629 C 11 42.6526 F 12 43.2483 C; D; E; F 13 44.4384 B; C; E 14 45.1853 C; G 15 46.0467 A; C; F 16 51.7242 C; E 17 54.6983 B; C; E; F; G 18 55.6067 C 19 57.7476 C; G 20 59.4127 C; E 21 60.9443 A; F 22 63.6334 C; E 23 67.2179 C; D; F 24 67.6378 C; D; F

(17) For FIG. 2b, the following correspondence table for the XRD plot applies:

(18) TABLE-US-00003 No. Pos. [2Th.] Matched by 1 19.6156 A; G 2 28.7071 B; F 3 30.5965 J; F 4 32.832 G; F 5 34.0318 H 6 35.6749 G; F 7 39.4727 A; C 8 40.2587 G; F 9 41.3136 L 10 42.4853 H; F 11 43.1009 J; F 12 44.3631 B; J; C 13 45.0056 G 14 45.7432 A; F 15 55.4584 C 16 57.6292 G; C 17 59.3768 J; C 18 62.5413 H; G; F 19 63.4204 I; J; F 20 67.0942 A; F 21 69.7642 B; F

(19) For FIG. 2c, the following correspondence table for the XRD plot applies:

(20) TABLE-US-00004 No. Pos. [2Th.] Matched by 1 19.6888 A; K; G 2 28.8465 K 3 30.5823 E; F 4 30.689 E; J 5 34.1462 K 6 34.596 E; K; F 7 35.7666 G; F 8 37.2334 F 9 39.6721 A; K 10 40.3821 K; F 11 41.3957 L 12 42.5934 F 13 43.1948 E; K; F 14 44.3628 E; 15 45.2055 K; G 16 46.0544 A; F 17 47.7699 K; F 18 51.7781 E; F 19 54.4895 E; L; G; F 20 55.6058 C 21 57.2297 E; A; J 22 59.319 J 23 60.6774 A; G; F 24 62.5686 G; F 25 63.4965 E; F 26 67.063 A; F

(21) For FIG. 2d, the following correspondence table for the XRD plot applies:

(22) TABLE-US-00005 No. Pos. [2Th.] Matched by 1 19.6306 K; A; G 2 28.8349 K 3 30.6535 E; C 4 33.0501 G; F 5 34.1283 K 6 35.7544 G; F 7 37.1051 C; F 8 39.5928 K; C; A 9 40.3438 F 10 41.3497 L 11 42.6181 F 12 43.2328 E; K; C; F 13 43.8319 G; F 14 44.4379 E; C 15 45.162 C; G 16 45.9434 C; A; F 17 47.9066 K; C; L; F 18 54.3276 C; L; F 19 55.5601 C 20 57.6956 C; G 21 59.4596 E; C 22 60.7162 C; A; F 23 62.6767 C; G; F 24 63.5352 E; C 25 67.2371 C; F

EXAMPLES

(23) General Catalyst Preparation:

(24) The catalyst for the invention can be prepared by impregnating salt solutions of the first metal, e.g. Co, and the second metal onto the support. Catalyst Preparation Science and Engineering, Edited by John Regalbuto, CRC Press, 2007, page 341, and Preparation of Catalysts I: Scientific Bases for the Preparation of Heterogeneous Catalysts edited by G. Poncelet, P. A. Jacobs, B. Delmon, pages 430-440, disclose exemplary catalyst preparations via an impregnation process. The salt solutions can be nitrates, chlorides, sulfides or organic complexes. After the impregnation the catalyst is dried between 80 C. and 150 C. and calcined between 500 C. and 700 C. The catalyst is reduced prior to the reaction by exposing it to H.sub.2 at a temperature of between 600 C. and 900 C. The catalyst mixture can also be prepared by coprecipitation of the relevant compound precursors. The catalyst can be shaped as pellets, extrudates or crushed into granules after the drying step. During the reduction, the catalyst of the invention forms an alloy (or a mixture of alloys) in the form of one or more bimetallic mixtures. During the reaction, the catalyst may form a ternary alloy with carbon, e.g. Co.sub.3SnC, or with nitrogen, e.g. CoSnN.

(25) General Hydrogen Cyanide (HCN) Preparation:

(26) The catalyst is prepared by reduction under an H.sub.2 atmosphere. Preheated streams of CH.sub.4 and NH.sub.3 were mixed and sent to the reactor containing a catalyst comprising a carrier or a support and bimetallic compound or component at a temperature of between 750 C. and 1000 C. At the exit of the reactor the outlet effluent was cooled to condense the hydrogen cyanide (HCN). The residual gas may be treated or recycled. The catalyst may be regenerated by oxidation under an O.sub.2 atmosphere.

Examples 1-8

(27) The catalyst was reduced at 850 C. in a flow of 10% H.sub.2 in N.sub.2 (using a flow rate of about 900 NmL/min) for 4 hours.

(28) The carrier is calcined alumina and the bimetallic compound or component is Co and Sn.

(29) The CoSn/Al.sub.2O.sub.3 catalysts were pressed into pellets (13 mm diameter, 3.5 mm height) and then the pellets were divided into fragments of to of the original size.

(30) The catalyst was regenerated with 1000 Nml/min of 21% O.sub.2 in N.sub.2 while the temperature was increased from 100 C. to 850 C. at a rate of 5 C. per minute.

(31) During the experiment, the gas product was analyzed for H.sub.2, CH.sub.4 and HCN content by a gas chromatograph equipped with a HayeSep Q column and a TCD detector. The CH.sub.4 concentration was measured through one separate GC program, while the HCN was measured through another.

(32) TABLE-US-00006 TABLE 1 The preparation of hydrogen cyanide from methane and ammonia in the presence of a catalyst comprising Co, Sn and alumina. HCN CH.sub.4 Co:Sn Flow Temperature (exit vol (exit vol Example (wt) (Nml/min) C. %) %) 1 5:12 897 750 0.0 2 5:12 897 850 0.275 3 5:12 897 950 0.297 4 10:24 897 850 0.340 9.01 5 10:24 445 850 0.590 8.08 6 10:24 303 850 0.540 7.53 7 10:24 897 950 0.227 8.01 8 10:24 445 950 0.259 7.46 The CH.sub.4:NH.sub.3 vol %/vol % is 10:10.

(33) TABLE-US-00007 TABLE 2 The preparation of hydrogen cyanide from methane and ammonia in the presence of a catalyst comprising Co, Sn and alumina. HCN CH.sub.4 Co:Sn Flow Temperature (exit vol (exit vol Example (wt) (Nml/min) C. %) %) 9 10:24 750 750 0.0 60 10 10:24 750 850 1.3 52 11 10:24 750 900 2.2 48.5 12 10:24 750 950 1.2 49 In the examples 9-12, the CH.sub.4:NH.sub.3 vol %/vol % is 70:30.