The catalyst receiving nitrous oxide and method

 

The invention relates to catalysts and methods of producing nitrous oxide (N₂O) by oxidation of ammonia with oxygen or oxygen-containing gas. Nitrous oxide is widely used in various fields of national economy: in a semiconductor, perfume, medical and food industries. The described catalyst and method for producing nitrous oxide by oxidation of ammonia with oxygen or oxygen-containing gas, comprising the mn containing the active ingredient, iron oxide, lanthanum oxide, oxide or mixture of oxides, alkaline earth metal and aluminum oxide. The catalyst contains as an active ingredient composition, a mixed amorphous oxide phase non-stoichiometric composition MnBi_xO_y(0,05x2,24; 2,08yare 5.36) or a mixture of amorphous oxide phase composition MnBi_xO_yand mn containing crystalline phase. The process of obtaining nitrous oxide by oxidation of ammonia with oxygen or oxygen-containing gas in the presence of mn containing catalyst of the above composition is carried out at a temperature of 250-450^oC. Technical affinage component. 2 S. and 4 C.p. f-crystals, 1 table.

The invention relates to catalysts and methods of producing nitrous oxide (N₂O) by oxidation of ammonia with oxygen or oxygen-containing gas. Nitrous oxide is widely used in various industries such as semiconductor, perfume, medical and food industries. In recent years there has been another area of application of catalytic oxidation of nitrogen oxide benzene to phenol.

Needs of nitrous oxide in various fields have resulted in increased interest in the development of various methods of its receipt. There are several ways of obtaining nitrous oxide, among which we can highlight a number of catalytic methods: 1. Catalytic reduction of nitrogen monoxide (NO) or carbon monoxide (CO) or hydrogen or a mixture of carbon monoxide and hydrogen (synthesis gas) in the presence of homogeneous catalysts [EP 54965, 01 21/22, 1982]; 2. Catalytic reduction of nitrogen monoxide or carbon monoxide, or hydrogen, or a mixture of carbon monoxide and hydrogen (synthesis gas) in the presence of heterogeneous catalysts, which are used noble metals of the platinum group deposited on carriers, for example, (1-5) wt is oxygen in the presence of heterogeneous catalysts based on metal oxides.

A known number of oxide catalysts for production of nitrous oxide by oxidation of ammonia, in particular, on the basis of manganese dioxide: MnO₂-Bi₂O₃[Pat. DE, 503200, 1930; Pat. CSR, 158091, 1973]; MnO₂-CuO [EP 799792, C 01 B 21/22, 1997]; MnO₂-Bi₂O₃-Fe₂O₃[Pat. DE, 503200, 1930; EP 799792, C 01 B 21/22, 1997]; MnO₂-CoO-NiO [ EP 799792, C 01 B 21/22, 1997].

The number of known catalysts containing manganese oxide, namely: Co₃O₄-A1₂O₃[Reference: Catalytic properties of substances. / Ed. by C. A. Reuter, 1968 ]; Pr₂O₃-Nd₂O₃-CeO₂[EP 799792, C 01 B 21/22, 1997].

Closest to the proposed catalyst is the catalyst for getting the nitrous oxide comprising oxides of manganese, bismuth and aluminum content, wt.%: (5,035,0) MnO₂- (4,530,0) Bi₂About₃- (90,535) Al₂About₃[Pat. RF 2102135, B 01 J 23/18, 1998; WO 9825698, B 01 J 23/18, 1998]. The catalyst used for obtaining nitrous oxide by oxidation of ammonia oxygen-containing gas. In particular, the catalyst containing, wt.%: 13 Mno₂- 11 Bi₂O₃- 76 Al₂About₃when processing of the reaction mixture composition is about 9. the following process parameters: the degree of conversion of ammonia99.2%, and the selectivity for N₂Oand NO (S_NO) - 87% and 2.8%, respectively.

The disadvantages of this catalyst is relatively high lower limit of the content of the oxides Mno₂and Bi₂O₃in the catalyst, at least a 9.5 wt.%, to obtain the required selectivity for N₂O. a Known catalyst shows a sufficiently high output of NO in the oxidation of ammonia, which is harmful impurities for subsequent use of the target product. Known catalyst has a fairly high bulk density in the range of 0.9-1.4 g/cm³that complicates its use in the apparatus of the fluidized bed because of the impossibility of the realization of the turbulent mode.

The invention solves the problem of obtaining an active and selective catalyst in the ratio of nitrous oxide by oxidation of ammonia with oxygen or oxygen-containing gas, including low content of the active component.

The problem is solved by catalyst receiving nitrous oxide comprising mn containing the active ingredient, an oxide or mixture of oxides, alkaline earth metal, iron oxide, lanthanum oxide and aluminum oxide. The catalyst contains as AK composition MnBi_xO_y(0,05x2,24; 2,08are 5.36) or a mixture of amorphous oxide phase composition MnBi_xO_yand mn containing crystalline phase. The content of components in the catalyst, wt. %: MnBi_xO_yor a mixture of MnBi_xO_yand mn containing crystalline phase - 0,75 - 65,0
Alumina - 99,235 - 0,005
Iron oxide - 0,005 - 99,235
The oxide of lanthanum - 0,005 - 99,235
The oxide or mixture of oxides of the alkaline earth metal - 0,005 - 99,235
As a mn containing crystalline phases it contains manganese oxide MP₂About₃and/or connection of the composition of Bi₂Mn₄O₁₀. The content of mn containing crystalline phase is, wt.%: 0,005-25,0.

The catalyst contains an oxide or mixture of oxides of alkaline earth metals selected from a number of: Mg, Ca, Sr, Ba.

The catalyst may optionally contain a spinel type MAl₂O₄, where M is an alkaline earth metal.

The task is also solved by a method of obtaining nitrous oxide by oxidation of ammonia with oxygen or oxygen-containing gas in the presence of mn containing catalyst of the above composition, the process is carried out at those who Ganz, bismuth, iron, lanthanum and alkaline earth metal with subsequent stages of drying at 120-150^oC and calcination at 400-750^oC. Or prepared by impregnation of the granules containing oxides of alkaline earth metals and aluminum oxide with subsequent stages of drying at 120-150^oC and calcination at 400-750^oC. Or deposition with subsequent mixing and forming of the catalyst components into pellets of the desired shape with the subsequent stages of drying at 120-150^oC and calcination at 400-750^oC. the Finished catalyst after calcination according to the RFA does not contain in its structure phases of oxides MnO₂and Bi₂O₃observed the presence of a characteristic "Gallo" mixed amorphous phase MnBi_xO_y. In the case of calcination of the catalyst at temperatures above 550-600^oWith the structure of the catalyst can be observed the formation of crystalline oxide phases MP₂About₃and mixed compounds of Bi₂Mn₄O₁₀. The resulting catalysts are characterized by a high selectivity for N₂O in the oxidation of ammonia-oxygen mixtures, even for samples with a relatively low content of active ingredient: mixed amorphous Mn-Bi oxide phase; give demoted the ora MV_xAbout_y/MO-Fe₂About₃-La₂About₃-Al₂About₃significantly smaller than the catalyst of the prototype Mno₂-Bi₂About₃/Al₂About₃the selectivity for nitrous oxide in the oxidation of ammonia to the above catalyst is 87-88% at the reaction temperature of 350-360^oC.

Salient features of the proposed catalyst is a catalyst composition and structure of the active component.

The catalytic properties of the proposed catalysts in the oxidation of ammonia-oxygen mixtures are examined in running the install and evaluate the selectivity to the target product N₂O and on the presence of incidental impurities NO. The reaction mixture of 8 vol.% NH₃, 9.% About₂Not - the rest is passed through the catalyst bed fractional composition of 0.25-0.50 mm at flow rate of 3600 h^-1. The reaction temperature is 350^oC. the Composition of the initial reaction mixture and the reaction products analyzed chromatographically; the NO concentration is determined using an analyzer ECOM-Omega (Austria).

The invention is illustrated by the following examples.

Example 1. 60 g of the granules media Al₂About₃containing 0,004 is of 39,59 g of salt MP(NO₃)₂6N₂O and 16,65 g of salt Bi(NO₃)₃5H₂O a 5% solution of HNO₃. The wet granules are dried under IR-dryer to dry friable state, then dried in a drying Cabinet at a temperature of 120^oC for 4 hours. The sample was then calcined in a furnace at a temperature amounts to 400-650^oC for 6 hours. The resulting catalyst has a composition, by weight. %: 25,0 MnBi_0.25O_2,38- 74,985 Al₂About₃- 0,005 MgO - 0,005 La₂O₃- 0,005 Fe₂O₃. The XRD pattern indicates the absence of a catalyst composition of the crystalline phase of oxides Mno₂and Bi₂O₃. The catalyst was tested in the oxidation of ammonia oxygen-containing mixture in the test conditions described above. Selectivity for nitrous oxideand nitrogen oxide (S_NO) respectively 87,4% and 2.4%.

Example 2. 58,4 g granules media Al₂About₃containing 0.004 g Fe₂O₃and 0.004 g La₂About₃, nitrate impregnated with a solution obtained by dissolving 39,59 g of salt MP(NO₃)₂6N₂O, 16,65 g of salt Bi(NO₃)₃5H₂O and 10,24 g of salt Mg(NO₃)₂and nitrogen oxide (S_NO) respectively of 87.8% and 0.2%.

Example 3. 60 g of the granules media MgO containing 0.004 g La₂About₃, 0.004 g Al₂About₃and 0.004 g Fe₂O₃, nitrate impregnated with a solution obtained by dissolving 39,59 g of salt MP(NO₃)₂6N₂O and 16,65 g of salt Bi(NO₃)₃5H₂O a 5% solution of NGO₃. The wet granules are dried under IR-dryer to dry friable state, then dried in a drying Cabinet at a temperature of 120^oC for 4 hours. The sample was then calcined in a furnace at a temperature amounts to 400-650b>O₃- 0,005 Fe₂O₃- 0,005 Al₂About₃. The XRD pattern of the catalyst shows the absence of the catalyst composition of the crystalline phase of oxides Mno₂and Bi₂O₃. The catalyst was tested in the oxidation of ammonia oxygen-containing mixture in the test conditions described above. Selectivity for nitrous oxideand nitrogen oxide (S_NO) respectively 87,0 and 0.3%.

Example 4. 60 g of the granules media Al₂About₃containing 0.003 g Fe₂O₃, 0.0024 g of MgO and 0.024 g of Cao, nitrate impregnated with a solution obtained by dissolving 1.0 g of salt MP(NO₃)₂6N₂O, 0.32 g of salt Bi(NO₃)₃5H₂O and 0.003 g of oxide of La₂O₃a 5% solution of NGO₃. The wet granules are dried under IR-dryer to dry friable state, then dried in a drying Cabinet at a temperature of 120^oC for 4 hours. The sample was then calcined in a furnace at a temperature amounts to 400-650^oC for 6 hours. The resulting catalyst has a composition, by weight. %: 0,75 MnBi_0,19O₂₂₉- 0,004 MgO - 0,04 Cao - 0,005 Fe₂O₃-0,005 La₂About₃- 99,196% Al₂O₃. The XRD pattern of the catalyst shows a lack with the oxidation of ammonia oxygen-containing mixture in the test conditions, described above. Selectivity for nitrous oxideand nitrogen oxide (S_NO) respectively of 80.6% and 0.9%.

Example 5. 60 g of the granules media Al₂About₃containing 0.0024 g of MgO and 0,0016 g Cao, nitrate impregnated with a solution obtained by dissolving 39,59 g of salt MP(NO₃)₂6N₂O, 13,32 g of salt Bi(NO₃)₃5H₂O, 0.004 g La₂About₃and 8.08 g of salt Fe(NO₃)₃N₂O a 5% solution of NGO₃. The wet granules are dried under IR-dryer to dry friable state, then dried in a drying Cabinet at a temperature of 120^oC for 4 hours. The sample was then calcined in a furnace at a temperature amounts to 400-650^oC for 6 hours. The resulting catalyst has a composition, wt.%: 25,0 MnBi_{of 0.25}O_2,38- 72,99 Al₂About₃- 0,003 MgO - 0,002 Cao - 0,005 La₂About₃- 2,0 Fe₂About₃. The XRD pattern indicates the absence of a catalyst composition of the crystalline phase of oxides Mno₂and Bi₂About₃. The catalyst was tested in the oxidation of ammonia oxygen-containing mixture in the test conditions described above. Selectivity for nitrous oxideand sub>, 0.004 g Fe₂O₃and 0.004 g La₂About₃, 104,97 g MP(NO₃)₂6N₂O, 56,76 g Bi(NO₃)₃5H₂O in nitric acid solution, neutralized with lime water to pH 7. Leave to stand for 30 min and filtered. The wet precipitate formed into pellets and dried in air. Then dried in an oven at 120-140^oC and calcined at 400-500^oC for 4 hours. The resulting catalyst has a composition, wt.%: 65,0 MnBi_0,32O_2,48to 2.0 CaO - 0,005 Fe₂O₃- 0,005 La₂About₃- 32,99 Al₂About₃. The XRD pattern of the catalyst shows the absence of the catalyst composition of the crystalline phase of oxides Mno₂and Bi₂O₃. The catalyst was tested in the oxidation of ammonia oxygen-containing mixture in the test conditions described above. Selectivity for nitrous oxideand nitrogen oxide (S_NO) respectively and 82.2% and 2.0%.

Example 7. 60 g of the granules media MgAl₂O₄impregnated with a nitric acid solution obtained by dissolving 29,69 g of salt MP(NO₃)₂6N₂O, of 10.93 g of salt Bi(NO₃)₃5H₂O, 0.75 g of oxide of La₂O the uly dried under IR-dryer to dry friable state, then dried in a drying Cabinet at a temperature of 120^oC for 4 hours. The sample was then calcined in a furnace at a temperature amounts to 400-650^oC for 6 hours. The resulting catalyst has a composition, wt.%: 18,0 MnBi_0,19O_{to 2.29}to 1.0 Fe₂O₃- 1,0 La₂O₃- 22,5 MgO - 57,5 Al₂About₃. The XRD pattern indicates the absence of a catalyst composition of the crystalline phase of oxides Mno₂and Bi₂O₃. The catalyst was tested in the oxidation of ammonia oxygen-containing mixture in the test conditions described above. Selectivity for nitrous oxideand nitrogen oxide (S_NO) respectively of 87.5% and 0.2%.

Example 8. 60 g of the granules media Al₂About₃containing 0.004 g MgO, 0.004 g La₂O₃and 0.004 g Fe₂O₃, nitrate impregnated with a solution obtained by dissolving 42,23 g of salt MP(NO₃)₂6N₂O and 15,32 g of salt Bi(NO₃)₃5H₂O a 5% solution of NGO₃. The wet granules are dried under IR-dryer to dry friable state, then dried in a drying Cabinet at a temperature of 120^oC for 4 hours. The sample was then calcined in a furnace at a temperature amounts to 400-650^oWith over 6 About₃- 0,005 MgO - 0,005 La₂About₃- 0,005 Fe₂O₃. The XRD pattern showed the absence of the catalyst composition of the crystalline phase of oxides Mno₂and Bi₂O₃. The catalyst was tested in the oxidation of ammonia oxygen-containing mixture in the test conditions described above. Selectivity for nitrous oxideand nitrogen oxide (S_NO) respectively 87,2% and 1.2%.

Example 9. 60 g of the granules media Al₂About₃containing 0.004 g MgO, 0.004 g La₂About₃and 0.004 g Fe₂About₃, nitrate impregnated with a solution obtained by dissolving with 40.2 g of salt MP(NO₃)₂6N₂O and 16,65 g of salt Bi(NO₃)₃5H₂O a 5% solution of NGO₃. The wet granules are dried under IR-dryer to dry friable state, then dried in a drying Cabinet at a temperature of 120^oC for 4 hours. The sample was then calcined in a furnace at a temperature amounts to 400-650^oC for 6 hours. The resulting catalyst has a composition, wt.%: 20,0 MnBi_{of 0.25}O_2,38is 1.58 MP₂About₃- 3,42 Bi₂Mn₄O₁₀- 74,985 Al₂About₃- 0,005 MgO - 0,005 La₂O₃- 0,005 Fe₂O₃. The XRD pattern showed the absence of cccii oxidation of ammonia oxygen-containing mixture in the test conditions, described above. Selectivity for nitrous oxideand nitrogen oxide (S_NO) respectively 87,0 and 1.1%.

Example 10. 60 g of the granules media MgAl₂O₄impregnated with a nitric acid solution obtained by dissolving 29,69 g of salt MP(NO₃)₂6N₂O, 12,49 g of salt Bi(NO₃)₃5H₂O and 1.54 g of oxide of La₂O₃an 8% solution of NGO₃. The wet granules are dried under IR-dryer to dry friable state, then dried in a drying Cabinet at a temperature of 120^oC for 4 hours. The sample was then calcined in a furnace at a temperature amounts to 400-650^oC for 6 hours. The resulting catalyst has a composition, by weight. %: 19,6 MnBi_{of 0.25}O_2,38- 2,0 La₂About₃- 78,4 MgAl₂O₄. The XRD pattern showed the absence of the catalyst composition of the crystalline phase of oxides Mno₂and Bi₂O₃. The catalyst was tested in the oxidation of ammonia oxygen-containing mixture in the test conditions described above. Selectivity for nitrous oxideand nitrogen oxide (S_NO) respectively 87,4 and 0.5%.

Thus, the present invention allows to reduce the release of NO in the process and with a lower bulk weight at a level of 0.65-0.7 g/cm³.

Claims

1. The catalyst for obtaining nitrous oxide by oxidation of ammonia with oxygen or oxygen-containing gas, comprising the mn containing active component and aluminum oxide, characterized in that it contains as an active ingredient composition, a mixed amorphous oxide phase non-stoichiometric composition MnBi_xO_y(0,05x2,24; 2,08yare 5.36) or a mixture of amorphous oxide phase composition MnBi_xO_yand mn containing crystalline phases, as well as lanthanum oxide, iron oxide and the oxide or mixture of oxides of the alkaline earth metal content, wt. %:
MnBi_xO_yor a mixture of MnBi_xO_yand mn containing crystalline phase - 0,75-65,0
Alumina - 99,235-0,005
Iron oxide - 0,005-99,235
The oxide of lanthanum - 0,005-99,235
The oxide or mixture of oxides of the alkaline earth metal - 0,005-99,235
2. The catalyst p. 1, characterized in that as the mn containing crystalline phases it contains the oxide of manganese Mn₂O₃and/or connection of the composition of Bi₂Mn₄O₁₀hat from 0.005 to 25.0 wt. %.

4. The catalyst PP. 1-3, characterized in that it contains an oxide or mixture of oxides of alkaline earth metals selected from a range of Mg, Ca, Sr, Ba.

5. The catalyst PP. 1-4, characterized in that it further comprises a spinel type l₂O₄, where M is an alkaline earth metal.

6. The method of obtaining nitrous oxide by oxidation of ammonia with oxygen or oxygen-containing gas in the presence of mn containing catalyst, wherein the process is carried out at a temperature of 250-450^oWith, and as a catalyst using the catalyst according to any one of paragraphs. 1-5.