Method of preparing supported palladium catalysts

FIELD: reduction-oxidation catalysts.

SUBSTANCE: invention relates to catalytic chemistry and, in particular, to preparation of deep-oxidation supported palladium catalysts, suitable, for example, in afterburning of motor car exhaust. Preparation involves depositing palladium from aqueous solution of palladium precursors followed by drying and calcination. Precursors are selected from nitrite anionic or cationic palladium complexes [Pd(NO2-)(H2O)3]Anx or [Pd(NO2-)n(H2O)m](Kat)y, wherein An are anions of acids containing no chloride ions, Kat is proton or alkali metal cation, n=3-4, m=0-1, x=1-2, and y=1-2. Nitrite ions are introduced into impregnating solution in the form of nitrous acid salts or are created in situ by reducing nitrate ions or passing air containing nitrogen oxides through impregnating solution. Ratio [Pd]/[NO2-] in impregnating solution is selected within a range 1:1 to 1:4.

EFFECT: eliminated chlorine-containing emissions, increased stability of chlorine-free impregnating solutions, reduced their acidity and corrosiveness, and increased catalytic activity in deep oxidation reactions.

2 cl, 1 tbl, 16 ex

 

The invention relates to catalytic chemistry, in particular to the preparation of supported palladium catalysts for deep oxidation that can be used in various processes, for example, when afterburning in autowipe.

The traditional method of preparation of palladium catalysts based on the application as a precursor deposited palladium chlorine-containing compounds, usually hydrochloric acid solutions H2PdCl4. The disadvantage of this method is, as is well known, the presence of chlorine, which along with the high acidity of the fluids used affects the properties alumapalooza catalysts, reducing their activity in oxidation reactions. The removal of residual chlorine is possible only when exposed to the reaction medium for 60-70 hours. After the catalyst reaches a stationary state (Starostin YEAR Preparation and study of supported oxide and metal catalysts for deep oxidation with adjustable distribution of active component: - Dessert. Kida. chem. Sciences. - Novosibirsk, 1987).

In addition, it is important to note that the presence of hydrochloric acid in the solution, and then, when thermal catalysts in the gas phase leads due to corrosion to premature wear of the equipment and environmental pollution.

<> When cooking alumapalooza, alumosilverpalladium and kremnicaslovakia catalysts of bichloride predecessors palladium is the most common use is as a precursor of the active component of the solution of palladium nitrate. Closest to the proposed method is a method of obtaining the aluminum-palladium catalyst impregnated alumina carrier with a solution of palladium nitrate (RF Patent No. 2102143, IPC B 01 J 23/4, a Method of producing a catalyst for purification of gases from nitrogen oxides. - 96116061; Appl. 02.08.96; Publ. 20.01.98, prototype). As described in this patent technique was synthesized catalyst was used for comparison with the catalysts obtained by our proposed method.

Although palladium nitrate in the preparation of catalysts has the advantage over palladium chloride, but has a significant drawback - the application of active component on the carrier is at capacity, although it is preferred chemisorption. But due to the dependence of chemisorption on the acidity of the solution of palladium nitrate, its use is limited due to leakage of unwanted processes. The concentration of acid in the impregnating solution is an important factor in the formation of the catalyst, so the effect on the dispersion caused actively what about the component and on the activity of the resulting catalysts. Typically, solutions of palladium nitrate stable only in an acidic environment. However, the high acidity of the impregnating solution leads to the suppression of palladium sorption, possibly due to competition of palladium cations with protons acid, and also contributes to the flow side of the process is the partial dissolution of the carrier Al2About3. At the stage of drying is pereosazhdeniya dissolved aluminum oxide on a carrier in the form of corresponding basic salts of aluminum together with the salt of the applied metal. Subsequent annealing of the aluminum salts formed crystalline or amorphous aluminum oxide, is able to block crystals of palladium (or palladium oxide), thereby reducing the activity of the catalyst. However, often, the use of strongly acidic solutions of salts of palladium just need to ensure the sustainability of the solutions in contact with the carrier Al2About3partially neutralizing the acid. Otherwise, in case of insufficient acid in the solution flows hydrolysis, leading to the precipitation of palladium hydroxide.

For aluminosilicate media and silica gel dissolution and pereosazhdeniya media uncharacteristically. But the strong acidity of the solution suppresses the chemisorption of palladium and on these media.

Thus, when using palladium nitrate to receive deposited palladium catalysts with desired reproducible properties it is necessary to strictly control the content of acid in the impregnating solution.

The purpose of this invention is the elimination of chlorine emissions from the preparation of supported palladium catalysts, improving the sustainability bichloride impregnating solutions, the reduction of acidity and corrosion ability and increased catalytic activity in the reaction of deep oxidation (combustion chamber).

The proposed method for the preparation of deposited palladium catalysts for deep oxidation involves the deposition of palladium from aqueous precursors on the carrier, followed by drying and calcination. As precursors for the deposition of use solutions of nitrite, anionic or cationic palladium complexes [Pd(NO2-)(H2O)3]Anxor [Pd(NO2-)n(H2O)m](Kat)ywhere An is the anion of the acid, not containing chloride ions, for example, NO3-, SO4-2CH3Soo-; Kat - proton or a cation of alkali metals; n=3-4; m=0-1; y=1-2 x=1-2. Nitrite ions injected into the impregnating solution or in the form of salts of nitrous acid, or by creating them in the impregnating solution recovery nitrate ions, or passing through an impregnating solution, the air containing the oxides of nitrogen, and the ratio of [Pd]:[NO2-] take in the range 1:1-1:4, and predominantly 1:1.

The difference we offer is of the procedure is the use of nitrite complexes of palladium in the preparation of supported palladium catalysts, that has a number of significant advantages. First, they have such important properties as ease of education and high stability in a wide pH range, which allows the synthesis of, for example, alumapalooza catalysts significantly reduce the acidity of the impregnating solution, necessary for the protection of salts of palladium from hydrolysis. Reduction of acidity, in turn, allows for the deposition of palladium is not the usual impregnation, and chemisorption, which is preferable as it leads to strong binding of the active ingredient with the carrier and, in principle, provide a higher dispersion of supported palladium. Secondly, the use of nitrite ion as ligand-stabilizer in comparison with other ions, for example, Cl-, SCN-convenient from the point of view of preparation of the catalysts, as high temperature processing, the nitrite ion is completely falling apart, not forming products, chemical catalyst and having corrosion activity. Methods of preparation of deposited palladium catalysts for deep oxidation on the basis of nitrite complexes of palladium are presented below.

In addition, in the process, it was found that the use of nitrite complexes of palladium as a precursor of the active component allows regulation shall determine the distribution of palladium in the pellet carrier by varying the ratio of [Pd 2+]:[NO2-] in the impregnation solution. It is known that nitrous acid and its salts form very stable complex compounds with palladium. Nitrite complexes of palladium (II) can also occur under the action of the nitrite ions on complex chlorides and bromides, replacing ions of Cl-and Br-in the internal sphere of palladium, although their stability is quite high. Varying the concentrations of palladium nitrate and nitrite ions in solution, it is possible to obtain complexes of different composition. The high stability of nitrite complexes of palladium (lg K4=21,6) allows them to exist without being subjected to hydrolysis in alkaline medium (pH 8) even in the case of a boiling solution that allows you to suggest their use for the preparation of palladium catalysts.

To understand the reasons for the high stability of the solution of Pd(NO3)2obtained by dissolving palladium mobiles in nitric acid, the state of palladium in it has been studied by NMR17O and14N spectroscopy. The NMR spectra obtained for solutions with concentrations Pd 57 and 28.5 mg/ml of 0.54 and 0.27 mol/l) at [HNO3]=5.0 and 2.5 M, respectively.

The NMR spectrum17O attended only line available, not coordinated with palladium anions NO3-(409 ppm) and water (5 ppm).

The NMR spectrum14N there was no line of nitrate-ion - NO 3 -coordinated with palladium, but noted wide line (22 ppm), which was attributed to nitrite ions (NO2-)associated with palladium. End NO2--ligand coordinate H2O - Pd - NO2-has a chemical shift that is equal to 74 ppm [Belyaev A.V., Fedotov M.A., Korenev SV // Coordination chemistry, 1989, T. 15, s - 1555], but it is not stable in the acidic environment [Fedotov M.A., Belyaev A.V. // Coordination chemistry, 1994, t.20, s-615]. Study the solutions had high acidity. This suggests that they NO2-is a bridging ligand associated with the palladium atom of nitrogen. The ratio of [Pd]: [NO2-] found equal to ˜1:1,5. Taking into account the error of the NMR measurements due to the large line width14NO2-(500 Hz) it can be [Pd]:[NO2-]=1:1 or 1:2. These NMR suggest that the palladium solution exists in the form of bridged complexes: either double HE-- NO2-bridge (given the low concentration of nitrite ligand), or double NO2-- NO2-bridge. These complexes, apparently, are polynuclear, which is confirmed by the observation of the Tyndall effect in the studied solutions.

Thus, the results of NMR measurement of the nitrate solution p is lady, prepared by dissolving Pd-mobile in HNO3conc., it can be concluded that a high stability due to the presence in the coordination sphere of palladium NO2-- ion battery. This ion forms with Pd(II) solid complexes: lgK=21,6±0,4 [Alimarin I.P., Shlensky V., Biryukov, A.A., etc. // proceedings of the USSR Academy of Sciences, series chem. Sciences, 1970, p.3-10]. As a consequence, the nitrite ion is a strong stabilizer of palladium from the hydrolysis and precipitation of Pd(OH)2. Nitrite ions are the product of the redox reaction of the dissolution of palladium mobile in concentrated nitric acid, which runs without extracting the gas, i.e. the reduced form of nitrogen is associated with palladium as its transition into the solution. [Cotton, F., Wilkinson, J. Modern inorganic chemistry. Chemistry of transition elements. M.: Mir, 1969, s].

Industrial solution of Pd(NO3)2less stable, as its preparation is partial removal of nitrite ions due to their oxidation to nitrate ions with multiple evaporation of the solution in a stream of air. For example, hydrolyzable most of the Aqua complex of palladium (II) you can see how strong the stabilizer from the drop Pd(OH)2is the nitrite ion at concentrations of palladium, typically used in the preparation of catalyst [Pd]=0.5 to 5 mg/ml So that p is coherent adding NaNO 2to a solution of the Aqua complex of palladium to the molar ratio of [Pd2+]:[NO2-]=1:1 and then, after establishing equilibrium of complex formation, the addition of NaOH in sufficient quantity to neutralize existing free solution HNO3and create relationships [Pd]:[OH]=1:2, does not lead to hydrolysis with the formation of Pd(OH)2at room temperature over a long observation time (month). It should be noted that the introduction of NaNO2in studying the solution of the Aqua complex of palladium nitrate leads to very rapid (1-2 min) to change its color from orange to intense yellow, indicating the rapid occurrence of NO2-in the coordination sphere of palladium. The heated alkaline solution for ˜30 minutes also does not lead to the deposition of palladium hydroxide. There is only a darkening in the education hydrosolidarity of palladium complexes [N. Kukushkin. // Coordination chemistry, 1982, vol. 8, s-281].

For the comparison of the obtained catalysts traditionally used catalysts based on Pd(NO3)2was synthesized catalyst (prototype) according to the information contained in the patent of Russian Federation №2102143.

Catalytic activity was determined using a flow-circulation installed in the reaction of deep oxidation is ETANA at T=500° With, the initial concentration of methane of 0.5% vol., the current concentration of 0.25% vol., i.e. the degree of conversion X=50%.

Below are examples of the preparation of catalysts by our proposed method and the example of the prototype.

Example 1.

To 23,7 ml of palladium nitrate solution with CPd=0.84 mg/ml and [HNO3]=0,006 M, obtained by dilution of an industrial solution of Pd(NO3)2, (TU-6-09-395-75) added 1.7 ml NaNO2[NaNO2]=0,11 M until the molar ratio of [Pd]:[NO2-]=1:1. According to NMR in solution is complex with the formula [Pd]:[NO2-]close to 1. The resulting solution stood for 0.5 hours, after which it made a sample (4.0 g) medium - γ-Al2About3(production Ryazan refinery (rnps), SID=200 m2/g). The suspension was shaken until complete adsorption of palladium (2 hours). Then the sample was dried at 100°C for 2 hours, then was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 4,5•10-2cm3CH4/(gcat.•).

Example 2.

To 22,0 ml of palladium nitrate solution with CPd=1.8 mg/ml and [HNO3]=0,014 M, obtained by dilution of an industrial solution of Pd(NO3)2added 3.4 ml of a solution of NaNO2[NaNO2]=0,11 M to molar with the relationship [Pd]:[NO 2-]=1:1. The ratio of [Pd]:[NO2-] in the complex, according to NMR, is also close to 1. The resulting solution stood for 0.5 hours, after which it entered the sample (4.0 g) medium - γ-Al2About3. The suspension was shaken until complete adsorption of palladium (5 hours). Then the sample was dried at 100°C for 2 hours, then was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is equal to 1.0%.

Activity in the oxidation of methane: 5,8•10-2cm3CH4/(gcat.•).

Example 3.

To 18.6 ml of palladium nitrate solution with CPd=4.3 mg/ml and [HNO3]=0.03 M, obtained by dilution of an industrial solution of Pd(NO3)2added 6.8 ml of a solution of NaNO2[NaNO2]=0,11 M until the molar ratio of [Pd]:[NO2-]=1:1. The resulting solution stood for 0.5 hours, after which it entered the sample (4.0 g) medium - γ-Al2About3. The suspension was shaken until complete adsorption of palladium (˜20 hours). Then the sample was dried at 100°C for 2 hours, then was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is equal to 1.9%.

Activity in the oxidation of methane: 9,0•10-2cm3CH4/(gcat.•).

Example 4.

The catalyst precursor is a solution of Pd(NO3)2derived from the metal the CSOs Pd as follows: a portion of PdCl 2weight 1 g) was filled with 1 ml of HCl conc., was stirred until complete dissolution PdCl2, was diluted with water to 50 ml and Then to this solution with constant stirring was gradually added zinc dust by weight 0.5 g until complete discoloration of the solution. From the resulting suspension was filtered palladium mobile, washed with water and concentrated acetic acid, and dried. Dry the mob poured a small amount of formic acid, a day after the acid was decanted and the mobile washed with water to remove acid. Then, the palladium black was dissolved by heating in HNO3conc., Prilepa it in small portions. The obtained solution with a concentration of palladium 64,2 mg/ml and the concentration of nitric acid in 5.0 mol/L.

When this method of obtaining a palladium nitrate hydrogen produced in the interaction of mobiles with nitric acid partially restores the nitrate ion to nitrite. According to the NMR nuclei N14and16palladium(II) this solution is associated with the nitrite ion in a molar ratio of [Pd]:[NO2-]≅1:1.

A sample (4.0 g) medium - γ-Al2About3was placed in 25 ml of palladium nitrate solution prepared by dissolving palladium metal in conc. HNO3with CPd=0.8 mg/ml and [HNO3]=0,06 M of the Suspension was shaken until complete adsorption of palladium (˜7 hours). ZAT is m, the sample was dried at 100° C for 2 hours and was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%. Activity in the oxidation of methane: 5,2•10-2cm3CH4/(gcat.•).

Example 5.

Preparation of a solution of Pd(NO3)2of Pd(OH)2: a portion of PdCl2poured HCl conc., was stirred and left to dissolve the salt, then, to the obtained solution in small portions with constant stirring was added NaOH in sufficient quantity to complete the deposition of palladium as Pd(OH)2. The precipitate thoroughly washed with H2O SW. on the filter to remove the chloride ions, the presence of which was determined by the appearance of white opalescence adding AgNO3in the washing water. Next to the wet precipitate of Pd(OH)2with stirring in small portions was added HNO3conc., the resulting solution of palladium nitrate was diluted with water to V=150 ml. characteristics of the obtained solution: CPd=24,4 mg/ml, [HNO3]=2,1 M

To 23,7 ml of palladium nitrate solution obtained by dissolving Pd(OH)2in HNO3with CPd=0,86 mg/ml and [HNO3]=0,07 M, was added 1.7 ml of a solution of NaNO2[NaNO2]=0,11 m to the molar ratio of [Pd]:[NO2-]=1:1. The ratio of [Pd]:[NO2-] in the complex close to 1. The resulting solution stood for 0.5 hours, after CEG is it introduced a sample (4.0 g) media - γ-Al2About3. The suspension was shaken until complete adsorption of palladium (˜7 hours). Then the sample was dried at 100°C for 2 hours, then was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 4,8•10-2cm3CH4/(gcat.•).

Example 6.

Media - 5% MgO/γ-Al2O3obtained by modifying the original γ-Al2O3: a portion MgO (2.5 g) was dissolved in acetic acid (V=42,5 ml), the resulting solution was poured γ-Al2About3, stirred and left to complete absorption of magnesium acetate. Then modified so the carrier was dried in the air and progulivali at a temperature of 600°C for 4 hours. The study received carrier by XRD did not reveal the presence of crystalline phase MgO γ-Al2About3probably, in this case, MgO is in the amorphous state or included in the spinel solid solution MgAl2O4-γ-Al2About3.

A sample (4.0 g) medium - 5% MgO/γ-Al2O3was placed in a palladium nitrate solution (25 ml), prepared as in example 4, with the concentration of palladium 0.8 mg/ml and the concentration of nitric acid to 0.06 M. the Suspension was shaken until complete adsorption of palladium (2 hours). Then the sample was dried at 100° C for 2 hours and was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 12,7•10-2cm3CH4/(gcat.•).

Example 7.

To 23,7 ml of palladium nitrate solution obtained by dissolving Pd(OH)2in HNO3as described in example 5, with CPd=0,86 mg/ml and [HNO3]=0,07 M was added 1.7 ml of a solution of NaNO2[NaNO2]=0,11 M until the molar ratio of [Pd]:[NO2-]=1:1. The resulting solution stood for 0.5 hours, after which it entered the sample (4.0 g) medium - 5% MgO/γ-Al2O3, the receipt of which is described in example 6. The suspension was shaken until complete adsorption of palladium (2 hours). Then the sample was dried at 100°C for 2 hours, then was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 12,3•10-2cm3CH4/(gcat.•).

Example 8.

Media - θ-Al2O3obtained by annealing γ-Al2About3at a temperature of 1000°C for 8 hours. Education θ-form of aluminum oxide is confirmed by x-ray analysis.

A sample (4.0 g) medium - θ-Al2O3was placed in a palladium nitrate solution (25 ml), prepared from palladium mobiles, as describe what about the example 4, with CPd=0.8 mg/ml and [HNO3]=0.06 mol/L. the Suspension was shaken until complete adsorption of palladium (5 hours). Then the sample was dried at 100°C for 2 hours, then was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 21,3•10-2cm3CH4/(gcat.•).

Example 9.

Different from the 8 that as the palladium precursor is palladium nitrate solution obtained by dissolving palladium hydroxide in nitric acid (method of synthesis in example 5), in which for the stabilization of the palladium from the hydrolysis entered sodium nitrite in the ratio of [Pd]:[NO2-]=1:1.

To 23,7 ml of palladium nitrate solution with CPd=0,86 mg/ml and [HNO3]=0,07 M was added 1.7 ml of a solution of NaNO2[NaNO2]=0,11 M until the molar ratio of [Pd]:[NO2-]=1:1. The resulting solution stood for 0.5 hours, after which it entered the sample (4.0 g) medium - θ-Al2About3, the receipt of which is described in example 8. The suspension was shaken until complete adsorption of palladium (5 hours). Then the sample was dried at 100°C for 2 hours, then was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 15,1•10-2cm3CH4/(gcat." C).

Example 10.

The hinge salt PdSO4•2H2O m=0,045 g) was added 0,013 g NaNO2to create molar relationship [Pd2+]:[NO2-]=1:1, the mixture was dissolved in 25 ml of water. According to NMR the whole nitrite ion was included in the complex with a ratio of [Pd2+]:[NO2-]=1:1. Then the solution was made sample (4.0 g) medium - γ-Al2About3and was shaken until complete adsorption of palladium. Then the sample was dried at 100°C for 2 hours and was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 4,7•10-2cm3CH4/(gcat.•).

Example 11.

Preparation of a solution of Pd(CH3COO)2was performed using Pd-mobiles, the technique of which is described in example 4. Palladium black was dissolved in acetic acid under heating, adding a few drops of HNO3then the acid was released prior to the crystallization of salt Pd(CH3COO)2the crystals which had separated and was washed with ether. The solution was prepared by dissolving crystals of Pd(CH3COO)2in the icy CH3COOH subsequent dilution with water.

To 25 ml of a solution of palladium acetate with CPd=0.8 mg/ml was added 1.7 ml of a solution of NaNO2[NaNO2]=0,11 M until the molar ratio of [Pd]:[NO2-]=1:1. The floor is built solution has stood for 0.5 hours, then it introduced a sample (4.0 g) medium - γ-Al2About3. The suspension was shaken until complete adsorption of palladium. Then the sample was dried at 100°C for 2 hours, progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 4,8•10-2cm3CH4/(gcat.•).

Example 12.

Missed ammonia mixed with air through the reactor with a platinum catalyst at a temperature of 500°s, then the air flow and NOx were sent within 30 minutes in the impregnating solution (23,7 ml) Pd(NO3)2prepared from Pd(OH)2as described in example 5, with CPd=0,86 mg/ml and [HNO3]=0,07 M According to NMR, the ratio of [Pd]:[NO2-] is close to 1. Then the solution was made sample (4.0 g) medium - γ-Al2O3and was shaken until complete adsorption of palladium. Then the sample was dried at 100°C for 2 hours and was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: a 5.5•10-2cm3CH4/(gcat.•).

Example 13.

A sample (4.0 g) media - amorphous aluminosilicate AS-5 (Al2O3=94,0%; SiO2=5,5%) (Condea) were placed in 25 ml of palladium nitrate solution prepared from Pd mobiles, as described in example 5, with the Pd=0.8 mg/ml and [HNO3]=0,06 M of the Suspension was shaken until complete adsorption of palladium. Then the sample was dried at 100°C for 2 hours and was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 8,4•10-2cm3CH4/(gcat.•).

Example 14.

A sample (4.0 g) media - aluminosilicate AS-30 (Al2O3=74,1%; SiO2=25,1%) (Condea) were placed in 25 ml of palladium nitrate solution prepared from Pd mobiles, as described in example 5, with CPd=0.8 mg/ml and [HNO3]=0,06 M of the Suspension was shaken until complete adsorption of palladium. Then the sample was dried at 100°C for 2 hours and was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 5,1•10-2see CH4/(gcat.•).

Example 15.

To 25 ml of a solution of palladium nitrate, obtained from Pd mobiles, as described in example 5, with CPd=0.8 mg/ml and [HNO3]=0,06 M has introduced a sample (4.0 g) of the carrier is silica gel KSK (Sbeats=230 m2/g). The suspension was shaken until complete adsorption of palladium, then the sample was dried at 100°C for 2 hours, then was progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 2,2•10-2cm3CH4/(gthe ATA. •).

Example 16 (the prototype).

On a portion of the media γ-Al2About3mass of 4 g for capacity consistently applied and 16.7 ml of a solution of Pd(NO3)2with CPd=1.2 mg/ml and [HNO3]=0,09 M After impregnation the sample was dried in air, then at 100°C for 2 hours, progulivali at 700°C for 4 hours. The concentration of palladium in the catalyst is 0.5%.

Activity in the oxidation of methane: 5,4•10-2cm3CH4/(gcat.•).

Data on testing of catalysts in the model reaction of methane oxidation are presented in the table:

td align="center"> 5,2
No.MediaImpregnating solutionCPd, %W*102cm3CH4/(gcat.•)
1.γ-Al2About3Pd(NO3)2prom.+NaNO20,54,5
2.γ-Al2O3Pd(NO3)2prom.+NaNO21,05,8
3.γ-Al2About3Pd(NO3)2prom.+NaNO21,99,0
4.γ-Al2About3Pd(NO3)2from Pd mobiles0,5
5.γ-Al2About3Pd(NO3)2of Pd(OH)2+NaNO20,54,8
6.5%MgO/γ-Al2About3Pd(NO3)2from Pd mobiles0,5a 12.7
7.5%MgO/γ-Al2O3Pd(NO3)2of Pd(OH)2+NaNO20,512,3
8.θ-Al2About3Pd(NO3)2from Pd mobiles0,521,3
9.θ-Al2About3Pd(NO3)2of Pd(OH)2+NaNO20,515,1
10.γ-Al2O3PdSO4+NaNO20,5the 4.7
11.γ-Al2O3Pd(CH3COO)2+NaNO20,54,8
12.γ-Al2O3Pd(NO3)2of Pd(OH)2+NOx0,55,5
13.The aluminosilicate AS-5Pd(NO3)2from Pd mobiles0,58,4
14.The aluminosilicate AS-30 Pd(NO3)2from Pd mobiles0,55,1
15.Silica gel KSKPd(NO3)2from Pd mobiles0,52,2
16.γ-Al2About3Pd(NO3)2prom. (prototype)0,5of 5.4

As can be seen from the table, deposited palladium catalysts prepared from precursors - nitrite complexes of palladium, have activity in the oxidation of methane, comparable or significantly higher (3, 6, 7, 8, 9), than the activity of the catalyst, prepared in the traditional way.

1. Method of preparation of deposited palladium catalysts for deep oxidation, including the application of palladium from aqueous precursors on medium with subsequent drying and calcination, wherein as precursors for the deposition of use solutions of nitrite anionic or cationic palladium complexes [Pd(NO2-)(H2O)3]Anxor [Pd(NO2-)n(H2O)m](Kat)ywhere An is the anion of the acid, not containing chloride ions, Kat - proton or a cation of alkali metals; n=3-4; m=0-1; x=1-2, y=1-2, nitrite ions injected into the impregnating solution, or in the form of salts of nitrous acid, or by creating them in PR is phytochem solution recovery nitrate ions, or passing through an impregnating solution, the air containing the oxides of nitrogen, and the ratio of [Pd]:[NO2-] in the impregnation solution take in the range of 1:1-1:4.

2. The method of preparation according to claim 1, characterized in that the preferred ratio [Pd]:[NO2-] in the impregnation solution 1:1.



 

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7 cl, 1 tbl, 10 ex

FIELD: gas treatment catalysts.

SUBSTANCE: invention provides catalyst consisted of inert carrier and catalytic coating containing platinum, rhodium, and oxide substrate, wherein catalytic coating includes: (i) at least one first substrate material selected from group consisted of first active aluminum oxide enriched with cerium oxide; mixed oxide, which is cerium oxide/zirconium dioxide; and zirconium dioxide component; provided that catalytic component in at least one first substrate material is first portion of the total quantity of catalyst platinum, wherein concentration of the first portion of the total quantity of catalyst platinum lies within a range of 0.01 to 5.0% of the total mass of catalyst-containing materials; and (ii) a second substrate material containing second portion of total quantity of platinum and rhodium as catalytic component, said second substrate material being second active aluminum oxide, wherein concentration of platinum plus rhodium on the second substrate material lies within a range of 0.5 to 20% of the total mass of the second substrate material. Method for preparing above catalyst is also provided.

EFFECT: increased catalytic activity and reduced catalyst preparation expenses.

17 cl, 3 dwg, 5 tbl, 3 ex

FIELD: catalyst preparation methods.

SUBSTANCE: invention relates to a method for preparing catalyst and to catalyst no honeycomb-structure block ceramic and metallic carrier. Preparation procedure includes preliminarily calcining inert honeycomb block carrier and simultaneously applying onto its surface intermediate coating composed of modified alumina and active phase of one or several platinum group metals from water-alcohol suspension containing, wt %: boehmite 15-30, aluminum nitrate 1-2, cerium nitrate 4-8, 25% ammonium hydroxide solution 10-20, one or several precipitate group metal salts (calculated as metals) 0.020-0.052, water-to-alcohol weight ratio being 1:5 to 1:10; drying; and reduction. Thus prepared catalyst has following characteristics: specific coating area 100-200 m2/g, Al2O3 content 5-13%, CeO2 content 0.5-1,3%, active phase (on conversion to platinum group metals) 0.12-0.26%.

EFFECT: simplified technology due to reduced number of stages, accelerated operation, and high-efficiency catalyst.

5 cl, 1 tbl, 10 ex

FIELD: catalyst preparation methods.

SUBSTANCE: method involves preparing porous carrier and forming catalyst layer by impregnation of carrier with aqueous solution of transition group metal salts followed by drying and calcination. Porous catalyst carrier is a porous substrate of organic polymer material: polyurethane or polypropylene, which is dipped into aqueous suspension of powdered metal selected from metals having magnetic susceptibility χ from 3.6·106 to 150·106 Gs·e/g: iron, cobalt, chromium, nickel, or alloys thereof, or vanadium and polyvinylacetate glue as binder until leaving of air from substrate is completed, after which carrier blank is dried at ambient temperature and then fired at 750°C in vacuum oven and caked at 900-1300°C. Caked blank is molded and then subjected to rolling of outside surface to produce carrier having variable-density structure with density maximum located on emitting area. Formation of catalyst layer is achieved by multiple impregnations of the carrier with aqueous solution of acetates or sulfates of transition group metals: iron, cobalt, chromium, nickel, or alloys thereof in alternative order with dryings at ambient temperature and calcinations to produced catalyst bed 50-80 μm in thickness. In another embodiment of invention, formation of catalyst layer on carrier is accomplished by placing carrier in oven followed by forcing transition group metal carbonate vapors into oven for 60-120 min while gradually raising oven temperature to 850°C until layer of catalyst is grown up to its thickness 50-80 μm.

EFFECT: improved quality of catalyst and reduced its hydrodynamic resistance.

8 cl, 1 tbl, 3 ex

FIELD: catalyst preparation methods.

SUBSTANCE: invention relates to alumina-supported catalyst preparation method and employment thereof in reactions of nucleophilic substitution of aromatic halides containing electron-accepting group. In particular, alumina support impregnated with alkali selected from alkali metal hydroxides is prepared by treating alkali metal hydroxide aqueous solution with aluminum oxide in organic solvent followed by drying thus obtained catalyst mixture at temperature not lower than 150°C. Catalyst is, in particular, used to introduce electron-accepting protective groups into organic compounds comprising at least one of -OH, -SH, and -NH, as well as in reaction of substituting amino, thio, or ether group for halogen in a haloarene and in preparation of 2-puperidinobenzonitrile.

EFFECT: simplified preparation of catalyst and regeneration of spent catalyst, and avoided involvement of dangerous reactants.

11 cl, 20 ex

FIELD: catalyst preparation methods.

SUBSTANCE: catalyst containing crystalline anatase phase in amount at least 30% and nickel in amount 0.5 to 2% has porous structure with mean pore diameter 2 to 16 nm and specific surface at least 70 m2/g. When used to catalyze photochemical reaction of isolation of hydrogen from water-alcohol mixtures, it provides quantum yield of reaction 0.09-0.13. Preparation of titanium dioxide-based mesoporous material comprises adding titanium tetraalkoxide precursor and organic-nature template to aqueous-organic solvent, ageing reaction mixture to complete formation of spatial structure therefrom through consecutive sol and gel formation stages, separating reaction product, and processing it to remove template. Invention is characterized by that water-alcohol derivative contains no more than 7% water and template consists of at least one ligand selected from group of macrocyclic compounds, in particular oxa- and oxaazamacrocyclic compounds containing at least four oxygen atoms, and/or complexes of indicated macrocyclic compounds with metal ions selected from group of alkali metals or alkali-earth metal metals, or f-metals consisting, in particular, of lithium, potassium, sodium, rubidium, cesium, magnesium, calcium, strontium, barium, lanthanum, and cerium used in amounts from 0.001 to 0.2 mole per 1 mole precursor. Sol is formed by stirring reaction mixture at temperature not higher than 35°C. Once formation of spaced structure completed, mixture is held at the same temperature in open vessel to allow free access of water steam and, when template is removed from the mixture, mixture is first treated with nickel salt solution and then with alkali metal borohydride solution until metallic nickel is formed.

EFFECT: increased sorption and photocatalytic properties of catalyst and enabled reproducibility of its property complex.

7 cl, 68 ex

FIELD: organic synthesis catalysts.

SUBSTANCE: invention provides improved method for preparing catalyst for synthesis of N-methylaniline from aniline and methanol. Method comprises impregnation of alumina carrier with copper nitrate solution, to which were added nitrates of modifying metals selected from group consisting of manganese, chromium, iron, cobalt, and zinc, after which impregnated carrier is dried at temperature ensuring effective conversion of deposited nitrates into oxides of corresponding metals. When calcined, catalyst is subjected to additional impregnation with copper ammine solution, wherein Cu content (on conversion to oxide) lies within 0.6 to 7.0% based on the weight of catalyst, then dried at 100-120°C, and re-calcined at 230-250°C. After first calcination Cu content is 10.1-13% and after the second it rises by 0.6-5.0%. Lifetime of catalyst increases by a factor of 1.3 to 2.

EFFECT: increased lifetime of catalyst.

1 tbl, 12 ex

FIELD: industrial organic synthesis catalysts.

SUBSTANCE: invention relates to environmentally friendly processes for production of isoalkanes via gas-phase skeletal isomerization of linear alkanes in presence of catalyst. Invention provides catalyst for production of hexane isomers through skeletal isomerization of n-hexane, which catalyst contains sulfurized zirconium-aluminum dioxide supplemented by platinum and has concentration of Lewis acid sites on its surface 220-250 μmole/g. Catalyst is prepared by precipitation of combined zirconium-aluminum hydroxide from zirconium and aluminum nitrates followed by deposition of sulfate and calcination in air flow before further treatment with platinum salts. Hexane isomer production process in presence of above-defined cat is also described.

EFFECT: increased catalyst activity.

5 cl, 2 tbl, 6 ex

FIELD: gas treatment catalysts.

SUBSTANCE: catalyst preparation method comprises depositing initially liquid soda glass onto metallic or glass-cloth surface, after which transition metal oxide mixture is sputtered onto wet surface, said transition metal oxide mixture containing, wt %: chromium (III) oxide 18-35, manganese (IV) oxide 18-35, alumina - the rest; or cupric oxide 5-15, chromium (III) oxide 10-15, alumina - the rest; or cupric oxide 12-35 and alumina - the rest. Resulting coating is dried in air during 1 day and then molded through stepwise heat treatment to temperature 400°C, which temperature is maintained for 2-2.5 h.

EFFECT: prolonged lifetime at the same catalytic efficiency.

3 tbl

FIELD: industrial inorganic synthesis and catalysts.

SUBSTANCE: invention provides ammonia synthesis catalyst containing VII group and group VIB metal compound nitrides. Ammonia is produced from ammonia synthesis gas by bringing the latter into contact with proposed catalyst under conditions favoring formation of ammonia.

EFFECT: increased ammonia synthesis productivity.

8 cl, 2 tbl, 19 ex

FIELD: conversion processes of chlorohydrocarbons; catalysts for joint production of chloroform and alkane chlorides.

SUBSTANCE: proposed catalyst is just product of interaction of ferrous chloride with nitrogen-containing organic derivative - amino alcohols of common formula R2NR1OH, where R=H or alkyl C1-C2, R1=C2-C5 alkyl applied on silica gel at content of FeCl2 of 0.7-1.5 mass-% of mass of silica gel at mass ratio of FeCl2/amino alcohol 1 : (5-20). Proposed catalyst makes it possible to increase life of heterogeneous catalyst, thus excluding stage of cleaning the products of process of joint production of chloroform and alkane chlorides and decreasing the cost of process due to replacement of copper chloride by ferrous chloride in the amount lesser by at least three times.

EFFECT: enhanced efficiency.

1 tbl, 12 ex

FIELD: organic synthesis catalysts.

SUBSTANCE: catalyst consists of complex [La(NO3)7][C5H10NH2]4 constituted by lanthanum nitrate, piperidine, and nitric acid taken in molar ratio 1:4:4, respectively.

EFFECT: achieved accessibility of catalyst.

1 tbl, 2 ex

FIELD: organic synthesis catalysts.

SUBSTANCE: catalyst consists of complex [Nd(NO3)7][C5H5NH]4 constituted by neodymium nitrate, pyridine, and nitric acid taken in molar ratio 1:4:4, respectively.

EFFECT: achieved accessibility of catalyst.

1 tbl, 2 ex

FIELD: inorganic synthesis catalysts.

SUBSTANCE: invention provides ammonia synthesis catalyst containing ruthenium as active ingredient supported by boron nitride and/or silicon nitride. Catalyst can be promoted by one ore more metals selected from alkali, alkali-earth metal, or rare-earth metals. Ammonia synthesis process in presence of claimed catalyst is also described.

EFFECT: increased temperature resistance of catalyst under industrial ammonia synthesis conditions.

4 cl, 6 ex

The invention relates to polyurethane chemistry and relates to the composition of the hydroxyl-containing component for the manufacture of flexible polyurethane foam and can be used in the furniture and automotive industries

FIELD: organic synthesis catalysts.

SUBSTANCE: catalyst for modifying colophony contains, as carrier, high-porosity cellular α-alumina-based block material and, as active catalyst fraction, sulfated group IV metal oxide and metallic palladium.

EFFECT: increased modification rate due to developed catalyst surface and eliminated disintegration and carry-over of catalyst.

5 ex

FIELD: industrial organic synthesis and catalysts.

SUBSTANCE: invention relates to a methyl ethyl ketone production process via catalytic oxidation of n-butenes with oxygen and/or oxygen-containing gas. Catalyst is based on (i) palladium stabilized with complexing ligand and (ii) heteropolyacid and/or its acid salts, in particular molybdo-vanado-phosphoric heteropolyacid having following composition: H11P4Mo18V7O87 and/or acid salt Na1.2H9.3Mo18V7O87, said complexing ligand being notably phthalocyanine ligand. Catalyst is regenerated by making it interact with oxygen and/or oxygen-containing gas at 140-190°C and oxygen pressure 1 to 10 excessive atmospheres. Oxidation of n-butenes is conducted continuously in two-stage mode at 15 to 90°C in presence of above-defined catalyst.

EFFECT: enhanced process efficiency due to increased stability of catalyst resulting in considerably increased productivity and selectivity.

7 cl, 1 dwg, 3 tbl, 8 ex

FIELD: textile, paper and chemical industries; protection of environment in production of bleachers, biocides and components of oxidizing processes.

SUBSTANCE: proposed catalyst contains one or more metals of platinum group used as active component, one or more polyolefines and activated carbon carrier. It is preferably, that polyolefines have molecular mass above 400 and are selected from ethylene homopolymers and ethylene copolymers with alpha-olefines, propylene homopolymers and propylene copolymers with alpha olefines, butadiene homopolymers and copolymers with styrene and other olefines, isoprene homopolymers and copolymers with other olefines, ethylene-propylene copolymers, ethylene-propylene diolefine three-component copolymers, thermoplastic elastomers obtained from butadiene and/or isoprene and styrene block-copolymers, both hydrogenized and non-hydrogenized. Hydrogen peroxide is produced in presence of said catalyst from hydrogen and oxygen in reaction solvent containing halogenated and/or acid promoter. Proposed catalyst makes it possible to increase degree of conversion and selectivity of process, to obtain aqueous H2O2 solutions at content of acids and/or salts at level of trace amount.

EFFECT: enhanced efficiency.

48 cl, 1 tbl,18 ex

FIELD: hydrogenation-dehydrogenation catalysts.

SUBSTANCE: preparation of catalyst comprises depositing active components on γ-alumina carrier at stirring, carrier being preliminarily treated with concentrated NaOH solution. Active components are deposited consecutively in three steps. In the first step, preliminarily prepared chitosan in acetic acid solution with KCl solution is deposited for 60-65 min; in the second step, sodium tetrachloropaladate(II) trihydrate Na2PdCl4·3H2O solution is deposited for 60-65 min; and, in the third step, hydrazine hydrate solution as reducing agent is added for 180-240 min. After each step, resulting suspension is filtered off, washed, and dried at 293-303K for 1-2 h in vacuum. Catalyst can be used in chemical industry and in processing of industrial and household wastes.

EFFECT: enhanced nitrate hydrogenation efficiency.

6 cl, 1 dwg, 6 ex

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