# US 10,441,942 B2 · Reaction tube and method for producing hydrogen cyanide > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,441,942 B2 - Document ID: US10441942B2 - Status: Granted - Kind: B2 - Application number: 15/028,415 - Filed: 2014-10-02 - Published: 2016-09-15 - Granted: 2019-10-15 - Earliest claimed: 2013-10-11 - Assignees: Evonik Degussa GmbH - Applicants: Evonik Degussa GmbH - Inventors: Martin Steffan; Martin Steurenthaler; Thomas Müller; Martin Körfer; Steffen Krill - Web page: https://patentgrep.com/patent/US10441942B2 ## CPC - B01J 23/42: Platinum - B01J 12/007: {in the presence of catalytically active bodies, e.g. porous plates} - B01J 19/0026: {Avoiding carbon deposits (inhibiting incrustation in general, C23F14/00, C23F15/00)} - B01J 19/006: {Baffles} - B01J 19/2415: {Tubular reactors} - B01J 21/04: Alumina - B01J 35/56: Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths - C01C 3/0229: {from hydrocarbons and ammonia in the absence of oxygen, e.g. HMA-process} - B01J 2219/0263: Ceramic - B01J 2219/30242: Star - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C01C: AMMONIA; CYANOGEN; COMPOUNDS THEREOF ({metal hydrides, monoborane, diborane or addition complexes thereof C01B6/00}; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; azides C01B21/08; {compounds other than ammonia or cyanogen, containing nitrogen, non-metals and optionally metals C01B21/082}; metal imides or amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; compounds containing silicon C01B33/00; compounds containing boron C01B35/00) ## Abstract The reaction tube for preparing hydrogen cyanide comprises a cylindrical tube composed of ceramic, a catalyst comprising platinum applied to the inner wall of the tube and also at least one insert composed of ceramic, having three or four fins pointing from the tube axis to the inner wall of the tube, which is inserted into the cylindrical tube, wherein the fins divide the tube interior space into substantially straight channels with substantially identical circle segment cross sections and wherein the mean gap between the ends of the fins and the inner wall of the tube is in the range of 0.1 to 3 mm. In the method for preparing hydrogen cyanide, ammonia and at least one aliphatic hydrocarbon having 1 to 4 carbon atoms are reacted in the reaction tube at 1000 to 1400° C. ## Claims ### Claim 1 A reaction tube for preparing hydrogen cyanide, comprising a cylindrical tube composed of ceramic and a catalyst comprising platinum applied to the inner wall of the tube, wherein at least one insert composed of ceramic is inserted into the cylindrical tube, said insert having three or four fins pointing from the tube axis to the inner wall of the tube, dividing the tube interior space into substantially straight channels with substantially identical circle segment cross sections and wherein the mean distance between the ends of the fins and the inner wall of the tube is in the range of from 0.5 to 3 mm and wherein the reaction tube has an internal diameter of 15 to 30 mm. ### Claim 2 (depends on 1) The reaction tube of claim 1, wherein the cylindrical tube is composed of tightly sintered aluminium oxide. ### Claim 3 (depends on 1) The reaction tube of claim 1, wherein the insert is composed of sintered aluminium oxide. ### Claim 4 (depends on 1) The reaction tube of claim 1, wherein the insert is coated with a catalyst comprising platinum. ### Claim 5 (depends on 1) The reaction tube of claim 1, wherein the ends of the fins are rounded. ### Claim 6 (depends on 1) The reaction tube of claim 1, wherein the fins have a mean thickness which is 0.25 to 2.5 times the mean thickness of the wall of the cylindrical reaction tube. ### Claim 7 (depends on 1) The reaction tube of claim 1, wherein said tube has exactly one insert inserted into the cylindrical tube. ### Claim 8 (depends on 7) The reaction tube of claim 7, wherein the insert is arranged in a central region of the cylindrical tube and has a length of 10 to 90% of the length of the cylindrical tube. ### Claim 9 (depends on 1) The reaction tube of claim 1, wherein the cylindrical tube is composed of tightly sintered aluminium oxide, the insert is composed of sintered aluminium oxide and coated with a catalyst comprising platinum, and the ends of the fins are rounded. ### Claim 10 (depends on 9) The reaction tube of claim 9, wherein said tube has exactly one insert inserted into the cylindrical tube. ### Claim 11 (depends on 10) The reaction tube of claim 10, wherein the insert is arranged in a central region of the cylindrical tube and has a length of 10 to 90% of the length of the cylindrical tube. ### Claim 12 (depends on 9) The reaction tube of claim 9, wherein the fins have the same thickness as the wall of the cylindrical tube. ### Claim 13 (depends on 12) The reaction tube of claim 12, wherein said tube has exactly one insert inserted into the cylindrical tube, having a length of 10 to 90% of the length of the cylindrical tube. ### Claim 14 A method for preparing hydrogen cyanide by reacting ammonia and at least one aliphatic hydrocarbon having 1 to 4 carbon atoms in the presence of a catalyst comprising platinum at a temperature of 1000 to 1400° C., wherein the reaction is carried out in at least one reaction tube, and wherein said reaction tube comprises a cylindrical tube composed of ceramic and a catalyst comprising platinum applied to the inner wall of the tube, wherein at least one insert composed of ceramic is inserted into the cylindrical tube, said insert having three or four fins pointing from the tube axis to the inner wall of the tube, dividing the tube interior space into substantially straight channels with substantially identical circle segment cross sections and wherein the mean distance between the ends of the fins and the inner wall of the tube is in the range of from 0.5 to 3 mm and wherein the reaction tube has an internal diameter of 15 to 30 mm. ### Claim 15 (depends on 14) The method of claim 14, wherein the hydrocarbons are composed of at least 90 vol % of methane. ### Claim 16 (depends on 14) The method of claim 14, wherein said cylindrical tube is composed of tightly sintered aluminium oxide, the insert is composed of sintered aluminium oxide and coated with a catalyst comprising platinum, and the ends of the fins are rounded. ### Claim 17 (depends on 16) The method of claim 16, wherein there is exactly one insert inserted into the cylindrical tube and the insert is arranged in a central region of the cylindrical tube and has a length of 10 to 90% of the length of the cylindrical tube. ### Claim 18 (depends on 16) The method of claim 16, wherein the fins of said insert have the same thickness as the wall of the cylindrical tube and there is exactly one insert inserted into the cylindrical tube, having a length of 10 to 90% of the length of the cylindrical tube.