Palladium-containing hydrogenation catalyst preparation method
FIELD: hydrogenation-dehydrogenation catalysts.
SUBSTANCE: palladium-containing hydrogenation catalyst, which can be used to control rate of autocatalytic hydrogenation reactions, is prepared by hydrogen-mediated reduction of bivalent palladium from starting compound into zero-valence palladium and precipitation of reduced zero-valence palladium on carbon material, wherein said starting material is tetraaqua-palladium(II) perchlorate and said carbon material is nano-cluster carbon black. Reduction of palladium from starting compound and precipitation of zero-valence palladium on carbon material are accomplished by separate portions.
EFFECT: increased catalytic activity, enabled catalyst preparation under milder conditions, and reduced preparation cost.
1 dwg, 1 tbl, 12 ex
The invention relates to the field of physical chemistry and can be used to regulate the speed of the auto-catalytic hydrogenation reactions.
Hydrogenation reactions are important industrial processes, implemented, usually in the presence of a catalyst, in particular, for the synthesis of acyclic and cyclic saturated organic compounds, high-quality gasoline, etc.
According to literature data (Grove D.E. Plat. Met., 2002, 46, (2) 92), about 75% of the industrial hydrogenation processes is carried out on Pd/C catalyst containing 5% palladium metal. Rich catalytic chemistry of palladium covers practically the whole range of reactions required for organic synthesis. The way to obtain a Pd/C catalyst based on the reduction of divalent palladium starting compound and the subsequent deposition of the recovered palladium on various activated carbons.
A known method of obtaining a palladium hydrogenation catalyst by restoring divalent palladium starting compound and deposition of the recovered palladium on carbon material, where the parent compounds are complexes of Pd (II)Tsuji, J. Palladium reagents and catalysts-innovations in organic syntheses. John Wiley & sons, Chichester. 1995. 595 R.; Grove D.E. Plat. Met., 2002, 46, (1) 48.
Also known is a method of obtaining palladium is about catalytic hydrogenation by restoring divalent palladium to nonvalence deposition of palladium and restored nonvalence palladium on carbon material, at the same time as the original connection using palladium (II)chloride, see H.M.Colquhoun, Y.Holton, et all, "New Pathways for Organic Synthesis" ("New pathways for organic synthesis"), translated from English, Mservice and Vgikesele, M., "Chemistry", 1989, s, 2nd paragraph from the top.
A solution of palladium chloride (8.2 g) in chloroethanol acid (20 ml of concentrated acid in 50 ml of water) is heated with stirring for 2 h, added with stirring to a hot (80° (C) suspension of coal in water (93 g in 1.2 l of water), pre-washed with nitric acid.
You can use virtually any coal with a sufficiently large specific surface treated with nitric acid (10%) for 2-3 h, followed by rinsing with water to remove the acid and dried at 100°C. Then added formaldehyde (8 ml of 37% solution) and sodium hydroxide solution until alkaline reaction. After 10 minutes, the catalyst is filtered off, washed with water (10×250 ml) and dried in vacuo over calcium chloride. The output of palladium 5% on coal 93-98%.
This method is adopted as the prototype of the present invention.
Its disadvantage is a small amount of activity obtained according to the method of the catalyst, the need for the implementation of the process of catalysis high (over 60° (C) temperature and pressure (over 5 ATM). This obyasnyau is by the complexity of the activation reaction sites of the catalyst, obtained by the method prototype. In addition, this method requires at least 5% of the recovered nonvalence palladium, which accounts for the high cost of the process.
The present invention laid the task of creating a method of obtaining a palladium hydrogenation catalyst, which would have a large catalytic activity could be carried out under more mild conditions (at room temperature and normal (atmospheric) pressure), as well as reduce the cost of implementation of the method.
According to the invention this problem is solved due to the fact that the method of obtaining a palladium hydrogenation catalyst by reduction with hydrogen of divalent palladium from the original connection to nonvalence deposition of palladium and restored nonvalence palladium on carbon material, as the starting compound used tetraamminepalladium (II) perchlorate, as the carbon material used nanocluster carbon black, and the recovery of palladium from the parent compound and the deposition restored nonvalence palladium on carbon material is carried out in individual portions.
The applicant has not identified the sources containing information about technical solutions, identical to the present invention, which allows to conclude if it responds thechild's criterion of "novelty".
Implementation characteristics of the invention leads to an important technical result: the result is used as the carbon material nanocluster carbon black (not containing fullerenes) significantly increases the catalytic activity of the recovered palladium, its content may be reduced by equal activity with 5% 2-3 times, and thanks to its deposition on the carbon carrier individual portions of the contents of the recovered palladium is reduced to fractions of a percent. Thus greatly reduced the price of the whole process.
The applicant has not found any sources of information containing data about the impact of an alleged distinguishing signs on achieved as a result of their implementation of the technical result. This, according to the applicant demonstrates compliance with this technical solution, the criterion of "inventive step".
The drawing shows the setup diagram for implementing the inventive method of obtaining a palladium hydrogenation catalyst.
Installation for implementing the method comprises a reactor 1 with a mixing device 2. Hydrogen is in the tank 3. The reactor 1 is connected to a gauge installation 4.
The method is implemented as follows.
In example 1, the catalyst content restored nonvalence palladium 0,1%Pd when it is a single deposition on a carbon carrier.
In examples 2 and 3, the catalyst containing 0.2% Pd at single and batch deposition, respectively.
In examples 4 and 5 0,3% Pd, in examples 6 and 7 0,4% Pd, 8 and 9 and 0.5% Pd, 10 and 11 - 1,0% Pd at single and batch deposition, respectively.
In example 12 the catalyst with a content of 5.0% Pd in a single deposition.
To obtain the catalyst in the first example, in the reactor 1 is placed 1,41 l of distilled water, make 4,21 mg carbon nanocluster carbon black add to 0.66 ml 6,0·10-2mol/l solution tetracaprylate (II) perchlorate [Pd(H2O)4](ClO4)2containing a 0.7 mol/l perchloric acid and stirred for 0.5 hours Then through the prepared solution is passed within 2 h of hydrogen. Stirring is stopped, the reaction mixture rest for 2-4 hours the precipitation is filtered by the filter SCHOTT, washed repeatedly with distilled water and dried in a vacuum desiccator over P2About5or over sodium hydroxide for 2 days. The output of the catalyst 1 is 98-99%.
In the examples 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 add in number, respectively,: 1,32; 1,98; 2,64; 3,30; 6,60; 33,0 ml of a solution of [Pd(H2O)4](ClO4)2with a concentration of 6.0·10-2mol/L.
In examples 3, 5, 7, 9, 11 deposition restored palladium on nanocluster carbon black was carried out in portions: p is the iMER 3 - 2 servings, in example 5 - 3 servings in example 7 - 4 servings in example 9 to 5 portions in example 11 - 10 servings.
After deposition of the first portion was carried out by exposure for 30 minutes and then for 2 hours missed hydrogen with stirring and then was carried out by the introduction of another portion.
The influence of the method of deposition of palladium on carbon nanocluster carbon and catalytic activity of the obtained products were examined in each sample using the following reactions:
reaction 2: 2Feaq +3+H2→2Feaq +2+2H+;
reaction 3: sunflower oil + H2→ hydrogenated products.
Each catalyst in the amount of 100 mg was placed in the reactor and added in the case of reaction (1) to 10 ml of distilled water; reaction (2) to 10 ml of an aqueous solution of 0.01 mol/l of ferric sulfate (III), containing 0,02 mol/l sulfuric acid; reaction (3) to 6 ml of vegetable oil "Sloboda". The reactor was evacuated and filled with hydrogen (reactions (2, 3) or eilenodontini mixture with a volume ratio of 1:1 (reaction (1).
The reaction was carried out at a temperature of 18-25°C and normal atmospheric pressure. The reaction rate was detected change amount of absorbed gases in time. The data obtained are shown in table 1.
The specific rate of hydrogenation (the amount of absorbed N2in moles/1 mole Pd hours) in reactions (1-3) in the presence of catalysts (1-12), at a temperature of 25°C, the hydrogen pressure is 1 ATM)
|# example||The concentration of Pd in the sample, %||Reaction 1||Reaction 2||Reaction 3|
|The specific rate of hydrogenation|
|once the deposition of Pd||portions of the deposition of Pd||once the deposition of Pd||portions of the deposition of Pd||once the deposition of Pd||portions of the deposition of Pd|
A method of obtaining a palladium hydrogenation catalyst by reduction with hydrogen of divalent palladium from the original connection to nonvalence deposition of palladium and restored nonvalence palladium on carbon material, characterized in that as starting compounds are used tetraamminepalladium (II) perchlorate, as the carbon material used nanocluster carbon black, and the recovery of palladium from the parent compound and the deposition restored nonvalence palladium on carbon material is carried out in individual portions.
FIELD: heterogeneous catalysts.
SUBSTANCE: catalyst contains porous carrier, buffer layer, interphase layer, and catalytically active layer on the surface wherein carrier has average pore size from 1 to 1000 μm and is selected from foam, felt, and combination thereof. Buffer layer is located between carrier and interphase layer and the latter between catalytically active layer and buffer layer. Catalyst preparation process comprises precipitation of buffer layer from vapor phase onto porous carrier and precipitation of interphase layer onto buffer layer. Catalytic processes involving the catalyst and relevant apparatus are also described.
EFFECT: improved heat expansion coefficients, resistance to temperature variation, and reduced side reactions such as coking.
55 cl, 4 dwg
FIELD: petrochemical process catalysts.
SUBSTANCE: preparation of catalyst comprises applying palladium compound onto silica cloth and heat treatment. Palladium compound is applied by circulation of toluene or aqueous palladium acetate solution through fixed carrier bed until palladium content achieved 0.01 to 0.5%. Palladium is introduced into cloth in dozed mode at velocity preferably between 0.1 and 5.9 mg Pd/h per 1 g catalyst. Heat treatment includes drying at temperature not higher than 150oC under nitrogen or in air and calcination in air or nitrogen-hydrogen mixture flow at temperature not higher than 450oC. Original silica cloth can be modified with 0.6 to 6.5% alumina. Palladium is uniformly distributed in silica cloth and has particle size preferably no larger than 15 Å. Invention can be used in treatment of industrial gas emissions and automobile exhaust to remove hydrocarbons.
EFFECT: deepened oxidation of hydrocarbons.
5 cl, 1 tbl, 4 ex
FIELD: supported catalysts.
SUBSTANCE: invention claims a method for preparation of catalyst using precious or group VIII metal, which comprises treatment of carrier and impregnation thereof with salt of indicated metal performed at working pressure and temperature over a period of time equal to or longer than time corresponding most loss of catalyst metal. According to invention, treated carrier is first washed with steam condensate to entirely remove ions or particles of substances constituted reaction mixture, whereupon carrier is dried at 110-130oC to residual moisture no higher than 1%.
EFFECT: achieved additional chemical activation of catalyst, reduced loss of precious metal from surface of carrier, and considerably increased lifetime.
5 cl, 9 ex