CN1400160A - Catalyst for producing hydrogen peroxide by using anthraquinone method - Google Patents

Abstract

The present invention discloses a catalyst for anthraquinone method to produce hydrogen peroxide and its preparation method. The load type noble metal catalyst for anthraquinone hydrogenation uses pretreated sepiolite or sepiolite-Al2O3 as carrier, containing 0.2-0l.4 wt% of Pt. Before use the sepiolite is impregnated with acid with different concentration according to different solid-liquid ratio for a certain time, then it is undergone the processes of filtering, washing, drying, tableting, roasting and pulverizing to obtain the invented product. Said catalyst is prepared with impregnation method, and features high activity and high selectivity. Under the condition of that pressure is 0.2 MPa. temp is 45 deg.C and operating fluid space velocity is 11.4 h(-1) (volume space velocity) its hydrogenation efficiency can be up to 8-12g(H2O2)/l, and its selectivity is up to above 97%.

Description

Catalyst for producing hydrogen peroxide by anthraquinone method

The invention relates to a supported noble metal catalyst for producing hydrogen peroxide by an anthraquinone method and a preparation method thereof.

The anthraquinone method is currently the most dominant method in the production of hydrogen peroxide at home and abroad, and the technology is relatively mature. Previously, nickel catalysts were used as catalysts for the hydrogenation of anthraquinones, but they were gradually eliminated due to their poor stability, easy spontaneous combustion in air, easy poisoning by oxygen and hydrogen peroxide, and difficulty in regeneration after failure. Since the 1960s, American Du Pont Company, FMC Company and Engelhard Company have successively developed and improved a series of palladium catalysts supported by Al ₂ O ₃ and SiO ₂ , etc. These catalysts have better activity and selectivity. In recent years, the price of Pd has continued to rise, while the price of Pt has been relatively stable. In order to reduce the operating costs of enterprises and utilize the abundant sepiolite resources in my country, the present invention discloses a sepiolite-loaded Pt catalyst for anthraquinone hydrogenation reaction.

The object of the present invention is to provide a kind of catalyst for producing hydrogen peroxide by anthraquinone method and preparation method thereof.

The content of the present invention is to provide a modification method of natural sepiolite, and use it to load Pt to prepare an anthraquinone hydrogenation catalyst with high activity and high selectivity for hydrogen peroxide production.

The catalyst carrier of the present invention is pretreated sepiolite or sepiolite-Al ₂ O ₃ . The active component consists of 0.2-0.4% by weight of Pt and 0.2-0.6% by weight of K ₂ O.

The catalyst carrier of the present invention is pretreated sepiolite or sepiolite-Al ₂ O ₃ , which is characterized in that the natural sepiolite is first immersed in an acid solution of a certain concentration with a certain solid-to-liquid ratio (weight ratio), The solid-liquid ratio can be 1:5-1:20, the acid can be nitric acid, hydrochloric acid or sulfuric acid, the acid concentration can be 0.5-5 mol/l, and the immersion time can be 2h-72h. After impregnation, filter, wash, and dry, mix sepiolite and Al ₂ O ₃ powder in a certain proportion, press into tablets, calcined, and pulverized into 20-50 meshes. The catalyst is prepared by impregnation method. The mixed solution of Pt salts and K salts is impregnated on sepiolite-Al ₂ O ₃ , dried at 100-120°C, calcined at 450-600°C, and finally treated with N ₂ -H ₂ was activated by reduction at 450°C to obtain a catalyst.

The salts of Pt used in the present invention can be chloroplatinic acid or platinum tetrachloride. The K salt used may be potassium nitrate or potassium acetate or potassium chloride or potassium carbonate.

The working liquid that the catalyst that the present invention adopts is the 2-ethylanthraquinone that dissolves with heavy aromatics and trioctyl phosphate (3: 1), and working liquid and hydrogen flow from top to bottom in a piston type, under 0.2MPa, At 45°C, the liquid space velocity is 11.4h ^-1 (volume space velocity), the hydrogenation efficiency of the reaction can reach 8-12g(H ₂ O ₂ )/l, and the selectivity can reach over 97%.

Example 1: Use 50g of natural sepiolite, soak it in 500ml of 1mol/l _HNO3 solution under stirring for 24h, filter, wash until the solution is close to neutral, dry, press into tablets, and roast at 450-600°C for 3h , crushed to 20-50 mesh for later use. Take 15g of the above-mentioned carrier, pour 15ml of a mixed solution containing 0.045Pt and 0.09gK into it, dry at 100-120°C for 3h, roast at 400-600°C for 3h, and finally use N ₂ -H ₂ at a space velocity of 300h ^-1 , Reduction at 450°C for 3 hours can produce the desired catalyst.

Put 7ml of the above catalyst into a φ8 stainless steel reactor, at 45°C and 0.2MPa, the liquid space velocity is 11.4h ^-1 (volume space velocity), and the hydrogenation efficiency of the reaction is 8.43g(H ₂ O ₂ )/l, The selectivity was 97.9%.

Example 2: The pretreatment method of the catalyst is the same as Example 1, except that the dried sepiolite powder and Al ₂ O ₃ powder are mixed in a ratio of 2:1, then pressed into tablets, and then calcined. The preparation method of catalyst is the same as example 1.

Using 7ml of this catalyst, using the same conditions as in Example 1, the hydrogenation efficiency of the reaction was 9.00g (H ₂ O ₂ )/l, and the selectivity was 100%.

Example 3: The catalyst pretreatment method is the same as Example 1, except that the dried sepiolite powder and Al ₂ O ₃ powder are mixed in a ratio of 1:1, and then pressed into tablets and roasted. The preparation method of catalyst is the same as example 1.

Using 7ml of the catalyst and using the same conditions as in Example 1, the hydrogenation efficiency of the reaction was 10.27g (H ₂ O ₂ )/l, and the selectivity was 99.7%.

Example 4: The preparation method of the catalyst is the same as Example 1, except that the dried sepiolite powder and Al ₂ O ₃ powder are mixed in a ratio of 1:2, and then pressed into tablets and roasted. The preparation method of catalyst is the same as example 1.

Using 7ml of this catalyst, using the same conditions as in Example 1, the hydrogenation efficiency of the reaction was 10.90g (H ₂ O ₂ )/l, and the selectivity was 98.3%.

Claims (6)

1. a hydrogen peroxide manufacture anthraquinone hydrogenation catalyst is characterized in that carrier is sepiolite or sepiolite-Al ₂O ₃, active ingredient is by 0.2～0.4% weight Pt, 0.2～0.6% weight K ₂O forms.

2. Preparation of catalysts method as claimed in claim 1 is characterized in that used carrier is to soak sepiolite or the sepiolite-Al that certain hour was handled with certain density acid under certain solid-to-liquid ratio ₂O ₃Catalyzer adopts immersion process for preparing, and the saline solution of Pt is dipped on the above-mentioned carrier, and 100～120 ℃ of dry 3h use N at last ₂-H ₂, air speed 300h ^-1, 450 ℃ of following reduction 3h can make required catalyzer.

3. method as claimed in claim 2 is characterized in that acid can be nitric acid or hydrochloric acid or sulfuric acid.

4. as claim 2 or 3 described methods, it is characterized in that the concentration of acid can be 0.5～5mol/l.

5. method as claimed in claim 2 is characterized in that solid-to-liquid ratio (weight ratio) can be 1: 5～1: 20.

6. method as claimed in claim 2 is characterized in that the treatment time can be 5～72h.