CS205987B1 - Catalyser on the basis of the vanadium pent oxide for oxidation of the anthracene to the 9,10-antrachinone - Google Patents

Description

The present invention relates to a vanadium pentoxide catalyst for the gas phase oxidation of anthracene to 9,10anthraquinone.

According to known processes, the gas phase oxidation of anthracene to form 9,10-anthraquinone is predominantly carried out on catalysts whose activity is based primarily on the catalytic action of vanadium pentoxide. This oxide is used in a variety of variations, either fused or supported. The carrier of the vanadium active mass is alumina, titanium dioxide, silica, ferric, chromium, manganese, silicon carbide, titanium, some metals such as aluminum, zeolites and the like. The activity and especially the selectivity of the catalyst is influenced by the addition of a wide variety of salts of elements of the periodic system. One of the numerous groups of these elements used to increase the selectivity of the catalyst in favor of the formation of 9,10-anthraquinone are alkali metals - i.e., lithium, sodium, potassium, rubidium and cesium salts. These salts are usually converted to the corresponding oxides when calcining the catalyst. The individual influence of the individual alkali metal oxides and their salts has not been comprehensively evaluated. Usually, the present inventions describe the beneficial effect of the alkali metals as a whole. However, in almost all types of anthracene oxidation catalysts, alkali metals contain potassium, which is used in the form of potassium hydroxide and potassium salt such as sulfate, oxalate, nitrate and the like when the active layer is applied to the catalyst support. In terms of catalyst selectivity and hence the yield of 9,10-anthraquinone, this has been achieved in recent years

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203907 highest values when using the catalyst system of TiC> 2-V20 .- ME20 P ₂ 0, .- Nb ₂ 0, where Me is Li, Na, K, Rb, Cs or Tl / Japanese Patent δ. 10550 /. This system is in many cases modified by some other oxides, in particular elements Ib, IIIa and IIb of the subgroups of the periodic system. On conventional catalysts, 9,10-anthraquinone is usually obtained in a yield of 70 to 82 mole% (e.g. British Patent 2. 754665J Indian Patent No. 66293 (German Patent No. 1016694). The following reaction conditions are most commonly used: bath temperature 360-430 ° C, space velocity 5000-8000 h ^-1 , feedstock concentration 20-40 g / m 2 reaction gas, final calcination temperature of the catalyst 350-600 ° C, and anthracene content in oxidized about 95 wt. Based on these findings, 18 to 30% of the starting anthracene is oxidized to products other than 9,10-anthraquinone - in particular to phthalic anhydride, 1,4-anthraquinone, 1,4-naphthoquinone and carbon oxides.

The essence of the vanadium oxide catalyst for the oxidation of anthracene to 9,10-anthraquinone is that it contains oxides of two alkali metals. The molar ratio of potassium oxide, vanadium oxide, iron oxide, manganese dioxide and lithium oxide or rubidium oxide or sodium oxide is 1 to 4 to 0.5 to 2.0 to 0.8 to 1.7 to 0.1 to 0.4 to 0.3 to 2.0. The ratio of active components to carrier, expressed as the weight ratio of potassium oxide to carrier, is 1 to 70 to 30.

The advantage of the catalyst prepared according to the invention lies above all in its higher selectivity. The combination of the two alkali metals resulted in an average yield of 5-10 mol% higher yield of 9,10-anthraquinone than conventional catalysts of this type. By using a new catalyst, higher labor productivity and a higher yield of 9,10-anthraquinone are achieved with the same anthracene consumption, which represents a considerable economic benefit. Another advantage of this catalyst is the possibility of obtaining a high purity product with a minimum content of acid impurities and other co-ingredients than is achieved with conventional catalysts of this type. The advantage is also the wide temperature range in which the maximum yield of 9,10anthraquinone can be obtained, while maintaining its high purity. The disclosed catalyst provides a conversion of anthracene to 9,10-anthraquinone above 90 mole% over a wide bath temperature range of 360 to 480 ° C. These yields correspond to those achieved with top catalysts.

The following examples describe the practical use of the catalyst.

Example 1 g of potassium hydroxide is dissolved in 1 dm 2 of water and 84 g of ammonium metavanadate are added to the solution at 60 ° C. The solution was then heated to 90 ° C until ammonia was removed. To this solution was added a solution of 130 g of crystalline ferrous sulfate and 16.4 g of crystalline manganese sulfate in 0.5 dm 2 of water while stirring. Finally, a solution of 90.5 g of rubidium sulfate in 0.5 dm 2 of water is added. 1 dm 2 of a sintered alumina carrier having a specific weight of 3.355 g / cm @ 2 and a mean grain diameter of 0.5 nm is then added to the resulting suspension. Water is then evaporated by successive heating and the activated carrier is activated. by gradual heating up to 50 ° C / h up to 360 ° C. The catalyst provided a conversion of anthracene to 9,10-anthraquinone of 91 mole% over a temperature range of 360 to 460 ° C, at a feedstock concentration of 44 g / m 2 and a contact time of 1 to 3 s.

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Example 2

The preparation of the catalyst was carried out in accordance with Example 1, except that 43.4 g of crystalline lithium sulfate was used instead of rubidium sulfate. The obtained suspension of catalytically active components was sprayed onto 1 bar of carrier, which was kept floating by an air stream of 200 ° C. After spraying the slurry, the catalyst is calcined to a temperature of 360 ° C. Upon oxidation of anthracene, this catalyst gave a yield of 92 mol% of 9,10-anthraquinone at a reaction temperature of 340 to 490 ° C, a raw material concentration of 41.5 g / m 2 and a contact time of 1 to 3 s.

Example 3

The preparation of the catalyst was carried out in accordance with Example 1 except that 109.21 g of crystalline sodium sulfate was used instead of rubidium sulfate. Upon oxidation of anthracene, the catalyst yielded 90.5 mole% of 9,10-anthraquinone under the conditions of Example 1.

Example 4

The preparation of the catalyst was carried out in accordance with Examples 1 and 2, except that 161.5 g of potassium hydroxide, 168 g of ammonium metavanadate, 170 g of crystalline ferrous sulfate, 32.8 g of crystalline manganese sulfate, 86.8 g of crystalline sulfate were used. lithium and 9500 g carrier. Under the reaction conditions of Example 1, this catalyst gave a 90 mole% yield of 9,10-anthraquinone upon oxidation of anthracene.

Example 5

Preparation of the catalyst of Example 1 except that 40.4 g of potassium hydroxide, 42 g of ammonium metavanadate, 80 g of crystalline ferrous sulfate, 78.0 g of crystalline manganese sulfate, 28.9 g of crystalline rubidium sulfate and 1000 g of carrier were used. Under the reaction conditions of Example 1, this catalyst gave an 89 mole% yield of 9,10-anthraquinone upon anthracene oxidation.

Claims (1)

SUBJECT OF THE INVENTION Catalyst based on vanadium pentoxide for the oxidation of anthracene to 9,10-anthraquinone in the gas phase, characterized in that the molar ratio of potassium oxide, vanadium oxide, iron oxide, manganese dioxide and lithium oxide, or sodium oxide or rebidene oxide is 1 to 4 0.5 to 2.0 to 0.8 to 1.7 to Q, 1 to 0.4 to 0.3 to 2.0, wherein the ratio of active components to the carrier, expressed by the weight ratio of potassium oxide to carrier is 1 to 70 to 30.