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Sodium borohydride reduction adopted method for preparing Pd/alpha-Al2O3 catalyst

A technology of sodium borohydride and catalyst, which is applied in the field of preparation of Pd/α-Al2O3 catalyst by reduction of sodium borohydride, can solve the problems of complex preparation method, reduction of catalyst dosage, high space-time yield of oxalate, and achieve low The effect of heat release and good active effect

Active Publication Date: 2014-12-10
贵州鑫醇科技发展有限公司
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  • Abstract
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  • Application Information

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Problems solved by technology

The introduction of additives can increase the space-time yield of oxalate to a certain extent, but the amount of Pd still remains at about 1%
Patents CN201110241310.9 and CN201110415823.7 provide a catalyst preparation method with a Pd content of 0.5-2%, but in this method, it is necessary to use a structure-directing reagent and a protective agent for reduction in an alkali-free liquid phase environment, and the preparation method is complicated. Therefore, how to further improve the utilization rate of the noble metal Pd of the catalyst in the CO gas-phase coupling synthesis of oxalate ester will further reduce the consumption of the catalyst, simplify the preparation method of the catalyst, reduce the cost and maintain a higher oxalic acid Ester space-time yield is of great significance

Method used

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  • Sodium borohydride reduction adopted method for preparing Pd/alpha-Al2O3 catalyst
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  • Sodium borohydride reduction adopted method for preparing Pd/alpha-Al2O3 catalyst

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preparation example Construction

[0024] The invention discloses a method for preparing Pd / α-Al by reducing sodium borohydride 2 o 3 The preparation method of catalyst, its preparation steps are:

[0025] (1) the precursor of palladium and the precursor of auxiliary agent are dissolved in the solution of certain pH value to make impregnation solution;

[0026] (2) The calcined α-Al 2 o 3 Add the balls to the dipping solution prepared in step (1), and then stand at 40-60°C for 6-24 hours;

[0027] (3) α-Al after processing by step (2) 2 o 3 Put the ball into the oven and dry at 100-200°C for 12-24 hours;

[0028] (4) α-Al processed by step (3) 2 o 3 Balls, washed thoroughly with deionized water;

[0029] (5) α-Al after washing 2 o 3 The balls are fully dried in the oven;

[0030] (6) sodium borohydride and dissolved in a certain volume of alkaline solution to obtain a reducing solution;

[0031] (7) α-Al after step (5) is processed 2 o 3 Add the spheres to the reducing solution prepared in step (...

example 1

[0042] (1) Preparation of catalyst

[0043] Dissolve 0.075g of palladium chloride and 0.040g of ferric nitrate as an auxiliary agent in 15ml of hydrochloric acid buffer at pH=1.1 to prepare an impregnating solution. Add 15g of calcined alumina balls to 15ml of the impregnating solution. Place it for 12 hours, then put it in a drying oven and dry it at 150°C for 20 hours; fully soak and wash it with 5 times the volume of deionized water, and wash it 10 times with an interval of 2-3 hours each time. Continue drying in the oven for 12 hours, add the obtained palladium-loaded alumina balls into the prepared reducing solution of sodium borohydride and sodium hydroxide at a concentration of 0.6 g / L, soak for 8 hours, wash and dry to obtain the finished catalyst product B2.

[0044] (2) Performance evaluation and life investigation

[0045] A fixed bed reactor is adopted, the diameter of the reaction tube is 15 mm, and the temperature is controlled in two stages. Add 15ml of cataly...

example 2

[0047] In Example 1, the concentrations in the sodium borohydride reducing solution added in the preparation of the catalyst are respectively: 0, 0.4g / L, 0.8g / L, 1.0g / L, 1.2g / L, that is, samples B0 and B1 of the cost example , B3, B4, B5.

[0048] Performance evaluation condition is the same as example 1, and the yield of dimethyl oxalate is as follows respectively:

[0049]

[0050] The B3 catalyst has been tested for 100h of life, and the activity is shown in figure 1 .

[0051] Sample Characterization:

[0052] Images via TEM (see Figure 2~3 ) and dispersion data (see table below), it can be seen that an appropriate amount of sodium borohydride concentration contributes to a substantial increase in dispersion, but as the concentration of sodium borohydride increases, the active components in the catalyst are reduced too quickly , the reunion grows up, and the dispersion decreases on the contrary.

[0053] sample name Metal Dispersion(%) Crystallite Si...

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Abstract

The invention discloses a sodium borohydride reduction adopted method for preparing a Pd / alpha-Al2O3 catalyst and belongs to the technical field of dimethyl oxalate preparation. The catalyst takes alpha-Al2O3 as a carrier and takes precious metal Pd nanoparticles as an active ingredient, wherein the content (by weight) of the active ingredient Pd in the catalyst is 0.05-1%. The dispersion degree of the active ingredient of the catalyst in the carrier can be controlled in a certain range; the metal dispersion degree of the catalyst prepared by the method is high, CO gas-phase carbonylation can be efficiently catalyzed at relatively low temperature and low precious metal load, so as to synthesize dimethyl oxalate, and the space-time yield of dimethyl oxalate reaches up to 1,150g / L / h (the space velocity is 2,400 / h).

Description

technical field [0001] The invention relates to a preparation method of a catalyst, in particular to a method for preparing Pd / α-Al by reducing sodium borohydride 2 o 3 Catalyst preparation method. Background technique [0002] At present, the loading amount of the noble metal Pd of the catalyst in the CO gas-phase coupling synthesis of oxalate is relatively high (the mass ratio of Pd to the catalyst support reaches 2%). However, the consumption of precious metals in the jewelry industry and industrial catalysts around the world is increasing day by day, resulting in a continuous shortage of precious metal resources and increasing the production cost of catalysts. Many domestic patents and documents have reported improved methods such as adding additives to the catalyst and using different palladium sources. The final activation step adopts the method of passing a reducing gas into a fixed-bed reaction tube for high-temperature reduction. Many domestic patents have reporte...

Claims

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Application Information

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IPC IPC(8): B01J23/44B01J37/16
Inventor 姚元根黄园园潘鹏斌张鑫覃业燕陈建姗
Owner 贵州鑫醇科技发展有限公司
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