CN104888866B - A kind of silicon magnesium complexes carrier and preparation method thereof - Google Patents

Abstract

The invention relates to a catalyst carrier, in particular to a silicon-magnesium composite carrier and a preparation method thereof. The silicon-magnesium composite carrier is supported by a composite of silicon, aluminum oxide, magnesium carbonate and its oxide, or a composite of silicon oxide, magnesium carbonate and its oxide, wherein Si : Al: Mg=5-7:0-3:2-5; the preparation method of the present invention is simple, and has high activity, high strength, and good selectivity; surface area and pore volume.

Description

A kind of silicon-magnesium composite carrier and preparation method thereof

(1) Technical field

The invention relates to a catalyst carrier, in particular to a silicon-magnesium composite carrier and a preparation method thereof.

(2) Background technology

The catalyst carrier, also known as the support, is one of the components of the supported catalyst. Catalytically active components are carried on the surface of the carrier, and the carrier is mainly used to support the active component to make the catalyst have specific physical properties, while the carrier itself generally does not have catalytic activity. Most carriers are products in the catalyst industry, commonly used are alumina carriers, silica gel carriers, activated carbon carriers, and some natural products such as pumice, diatomaceous earth, etc. At present, most of the carrier cue balls are prepared by pelletizing method or extruding method, and then the final catalyst carrier is obtained by activation roasting and/or superheated steam pore expansion treatment. The disadvantages of this process are that it is difficult to achieve the ideal pore diameter, specific surface area and The small pore volume will result in a decrease in the activity of the carrier and a decrease in the exchange volume, which will affect the output per unit volume and increase the amount of the carrier when catalyzing the synthesis of products.

(3) Contents of the invention

In order to make up for the deficiencies of the prior art, the invention provides a silicon-magnesium composite carrier and a preparation method thereof.

The present invention is achieved through the following technical solutions:

A silicon-magnesium composite carrier, characterized in that: it includes a composite composed of silicon, aluminum oxide, magnesium carbonate, and magnesium oxide, or a silicon oxide, magnesium carbonate, and magnesium The composite composed of oxides is used as the carrier.

The preparation method of above-mentioned silicon-magnesium composite carrier comprises the following steps:

(1) Add 1000ml of sodium silicate aqueous solution and 20% ammonia water to the beaker in sequence, control the pH value of the system to 9-11 through 20% ammonia water, and raise the temperature to 50-60°C under stirring;

(2) Add 500ml of magnesium nitrate or a mixed solution of magnesium nitrate and aluminum nitrate to the above mixture and mix evenly. After stirring for 1 hour, add 20% hydrochloric acid to adjust the pH value of the system to 4-6, and then stir for 1 hour;

(3) After the stirring is completed, add 2mol/L ammonium carbonate solution to the system to adjust the pH value of the system to 8, then raise the temperature to 80-90°C, stir for 6 hours, and then age for 40 hours to obtain the precipitate;

(4) Filter and wash the precipitate, dry it at 100-130°C, bake it at 400-600°C for 5 hours, and crush it through a 200-mesh sieve to obtain the carrier.

The concentration of the above-mentioned sodium silicate aqueous solution is: calculated as silicon dioxide, the concentration is 40-58 grams of silicon dioxide per liter of sodium silicate aqueous solution.

The concentration of the magnesium nitrate added in the above-mentioned step (2) is: in magnesium oxide, the concentration is 70-85 grams of magnesium oxide/liter of magnesium nitrate.

The concentration of the aluminum nitrate added in the above step (2) is: calculated as alumina, the concentration is 50-100 grams of alumina/liter.

Wherein, the carrier has a pore volume of 0.6-1.5 ml/g and a specific surface area of 55-130 m ² /g.

The mass ratio of silicon, aluminum and magnesium in the carrier is silicon:aluminum:magnesium=5-7:0-3:2-5.

The beneficial effects of the present invention are: the present invention provides a silicon-magnesium composite carrier, wherein Si:Al:Mg=5-7:0-3:2-5; the preparation method of the present invention is simple, and has high activity and high strength , good selectivity; and the present invention adopts the co-precipitation method to prepare the carrier, which increases the specific surface area and pore volume of the carrier.

(4) Specific implementation methods

Example 1:

Add 1000ml of sodium silicate aqueous solution (water glass, the same below, product of Qingdao Soda Soda Factory) with a concentration of 44 grams of silicon dioxide/liter in terms of silicon dioxide successively in a precipitation container, and add 1000ml of sodium silicate solution with 20% ammonia water (Kaiyuan Chemical Industry Co., Ltd.) Reagent factory product) to control the pH value of the system to 10-11, after stirring the temperature to 60°C, add 250ml of magnesium nitrate solution (product of Tianjin Yaohua Reagent Factory) and the following 250ml mixed solution of aluminum nitrate (product of Shenyang Reagent No. 1 Factory) solution with an alumina meter concentration of 99.7g/l, stirred at 45-60°C for 1 hour, then adjusted the pH value to 4-6 with 20% hydrochloric acid , stirred for 1 hour, adjusted the pH value to 8 with 2M ammonium carbonate solution, raised the temperature to 80-90°C, continued to stir for 6 hours, then unloaded, aged for 40 hours, filtered and washed, and dried at 125°C. After calcining at 550°C for 5 hours, the carrier S _A was obtained by crushing and passing through a 200-mesh sieve.

Example 2:

Add 1000ml of sodium silicate (product of Qingdao Soda Soda Factory) aqueous solution with a concentration of 50.6 grams of silicon dioxide per liter in a sedimentation container, and control the system with 20% ammonia water (product of Kaiyuan Chemical Reagent Factory). The pH value is 10-11. After heating up to 60°C under stirring, add 250ml of magnesium nitrate solution (product of Tianjin Yaohua Reagent Factory) with a concentration of 80.7 grams of magnesium oxide per liter as magnesium oxide and a solution of 55.9 grams of magnesium oxide as aluminum oxide. gram of alumina/liter of aluminum nitrate (product of Shenyang Reagent No. After adjusting the pH value of the ammonium carbonate solution to 8, the temperature was raised to 80-90°C, and the stirring was continued for 6 hours, then unloaded, aged for 40 hours, filtered and washed, and dried at 125°C. After calcining at 550°C for 5 hours, the carrier S _B was obtained by crushing and passing through a 200-mesh sieve.

Example 3:

Add 1000ml of sodium silicate (product of Qingdao Soda Soda Factory) aqueous solution with a concentration of 55.2 grams of silicon oxide per liter in a sedimentation container in sequence, and control the pH value of the system with 20% ammonia water (product of Kaiyuan Chemical Reagent Factory) After heating to 60°C under stirring, add 500ml of magnesium nitrate solution (produced by Tianjin Yaohua Reagent Factory) with a concentration of 81.0 grams of magnesium oxide/liter in terms of magnesium oxide, and stir for 1 hour at 45-60°C Finally, use 20% hydrochloric acid to adjust the pH value to 4-6, stir for 1 hour, adjust the pH value to 8 with 2M ammonium carbonate solution, raise the temperature to 80-90°C, and continue stirring for 6 hours, then unload and age After 40 hours, filter and wash, and dry at 125°C. After calcining at 550° _C for 5 hours, the carrier SC was obtained by crushing and passing through a 200-mesh sieve.

Table 1 The component content of the carrier in each embodiment of the present invention

Claims (5)

1. A silicon-magnesium composite carrier, characterized in that: comprise a compound composed of oxides of silicon, aluminum, carbonates of magnesium and magnesium, or by carbonates of oxides of silicon and magnesium The compound composed of magnesium oxide is the carrier; the pore volume of the carrier is 0.6-1.5 ml/g, and the specific surface area is 55-130 m ² /g; The preparation method of the silicon-magnesium composite carrier includes the following steps: (1) sequentially add 1000ml of sodium silicate aqueous solution and 20% ammonia water into the precipitation container, control the pH value of the system to 9-11 by 20% ammonia water, and stir Raise the temperature to 50-60°C; (2) Add 500ml of magnesium nitrate or a mixed solution of magnesium nitrate and aluminum nitrate to the above mixed solution and mix evenly. After stirring for 1 hour, add 20% hydrochloric acid to adjust the pH value of the system to 4-6, and then stir 1h; (3) After the stirring is completed, add 2mol/L ammonium carbonate solution to the system to adjust the pH value of the system to 8, then raise the temperature to 80-90°C, stir for 6 hours, and then age for 40h to obtain a precipitate; ( 4) Filter and wash the precipitate, dry it at 100-130°C, bake it at 400-600°C for 5 hours, and crush it through a 200-mesh sieve to obtain the carrier. 2. The silicon-magnesium composite carrier according to claim 1, characterized in that: the concentration of the sodium silicate aqueous solution is: calculated as silicon dioxide, the concentration is 40-58 grams of silicon dioxide per liter of sodium silicate aqueous solution. 3. The silicon-magnesium composite carrier according to claim 1, characterized in that: the concentration of magnesium nitrate added in the step (2) is: calculated as magnesium oxide, the concentration is 70-85 grams of magnesium oxide/liter of magnesium nitrate . 4. The silicon-magnesium composite carrier according to claim 1, characterized in that: the concentration of aluminum nitrate added in the step (2) is: calculated as alumina, the concentration is 50-100 g alumina/liter. 5. The silicon-magnesium composite carrier according to claim 1, characterized in that: the mass ratio of silicon, aluminum, and magnesium in the carrier is, silicon:aluminum:magnesium=5-7:0-3:2-5 .