RU2626238C1 - Catalyst for dehydrogenating of alkylaromatic hydrocarbons - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a catalyst for the dehydrogenation of alkylaromatic hydrocarbons, comprising oxides or iron, potassium, cesium and/or rubidium, magnesium and/or calcium, molybdenum, samarium and portland cement, europium oxide, decomposing to oxides, at the following component ratio, wt % (in terms of oxides): potassium oxide - 8-22, magnesium oxide and/or calcium oxide - 0.5-10, molybdenum oxide - 0.5-5, portland cement - 5-10, samarium oxide - 0.3-1.5, europium oxide - 0.005-0.030, cesium or rubidium oxide - 0.05-1.50, iron oxide - the rest.

EFFECT: increased catalytic activity, resistance to the action of catalytic poisons and a reduction in its cost.

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Description

The invention relates to the production of catalysts, namely the production of catalysts for the dehydrogenation of alkylaromatic hydrocarbons.

A known catalyst for the dehydrogenation of alkylaromatic compounds of the following composition, mass. %: potassium oxide and / or potassium ferrite - 8-22; magnesium oxide and / or ferrite and / or calcium oxide - 0.5-10; molybdenum oxide - 0.5-5; cerium oxide - 1-8; Portland cement - 2-12; strontium oxide and / or ferrite - 0.5-10; lanthanum oxide and / or neodymium oxide - 0.01-1; iron oxide - the rest. Additionally, the catalyst may contain oxide and / or ferrite of rubidium and / or cesium in an amount of 0.05-5 wt. % (Patent RU 2187364, IPC ⁷ В01J 23/745, B01J 23/887, 2002).

A disadvantage of the known catalysts is that the promoting component is washed out when exposed to water vapor at high temperature, as a result of which the catalyst gradually loses activity. This, in turn, leads to the need to increase the temperature of synthesis and increase the dilution of the reaction mixture with water vapor, that is, energy costs increase.

Closest to the proposed solution is a catalyst for the dehydrogenation of alkylaromatic hydrocarbons of the following composition: mass. %: potassium oxide - 8-22; magnesium oxide - 0.5-10; molybdenum oxide - 0.5-5; Portland cement - 2-12; samarium oxide - 1-5; cesium or rubidium oxide - 0.05-5; iron oxide - the rest (Patent RU 2509604 C1, IPC B01J 23/745, B01J 23/887, 2014).

The main disadvantage of the known catalyst is the high cost of the catalyst due to the use of samarium and alkaline promoters (cesium and rubidium).

The objective of the present invention is to obtain a catalyst with high catalytic activity and resistance to catalytic poisons at a lower content of samarium oxide; expanding the range of catalysts for the dehydrogenation of alkyl aromatic hydrocarbons with constant high technical characteristics and reducing their cost.

This problem is solved due to the fact that a catalyst for the dehydrogenation of alkyl aromatic compounds is proposed, including iron oxide, potassium compounds, magnesium and / or calcium compounds, rubidium and / or cesium compounds, molybdenum oxide, Portland cement, samarium oxide, europium oxide in the following components (in terms of oxides), mass%: potassium compounds - 8-22; magnesium compounds and / or calcium compounds - 0.5-10; molybdenum oxide - 0.5-5; Portland cement - 5-10; samarium oxide - 0.3-1.5; europium oxide - 0.005-0.030; compounds of rubidium and / or cesium in an amount of 0.05-1.50 wt. %; iron oxide - the rest.

The difference between the proposed catalyst and the prototype is the reduction in its composition of samarium oxide, used as a stabilizer of the activity of the catalyst and increasing its resistance to catalytic poisons, by partially replacing it with a small amount of europium oxide, as well as reducing the dosage of rubidium and / or cesium oxides.

As raw materials for obtaining the inventive catalyst can be used oxides or decomposable to oxides of the compounds of these components.

The proposed catalyst is prepared by mixing in a predetermined ratio of finely ground oxides or compounds of iron, oxide and / or decomposable compounds of molybdenum, samarium oxide, magnesium and / or calcium compounds that are easily decomposed to oxide. The components are mixed and soaked in an aqueous solution of alkaline promoters, for example, carbonates and / or hydroxides of potassium, rubidium and / or cesium. Portland cement is introduced at the stage of mixing the dry catalyst components.

The catalyst mass is stirred for 0.5-2.5 hours to obtain a homogeneous mass, then formed by extrusion into bundles, dried at 100-170 ° C and calcined at 550-750 ° C.

The invention is illustrated by the following examples.

Example 1

Dry catalyst components, g: iron oxide - 132.74; molybdenum oxide - 2; Portland cement - 24; samarium oxide 1; europium oxide - 0.04; magnesium oxide - 10, mixed for 1 hour. Add 30 ml of an aqueous solution containing 42 g of potassium carbonate and 0.92 g of cesium carbonate. The catalyst mass is stirred for 1.75 hours to obtain a homogeneous mass, then formed by extrusion into bundles with a diameter of 3.0 mm, dried at a temperature of 120 ° C and calcined at 650 ° C for 3 hours.

Get the catalyst composition, mass. %: iron oxide - 66.37; potassium carbonate - 14.3 (counting on oxide); cesium carbonate (counting as oxide) - 0.8; magnesium oxide - 5; molybdenum oxide - 1; Portland cement - 12; samarium oxide - 0.5; europium oxide - 0.02.

The tests of the catalyst are carried out in the reaction of dehydrogenation of ethylbenzene to styrene at a temperature of 600 ... 620 ° C, a feed rate of liquid ethylbenzene of 0.5 ... 1.5 l / l of catalyst per hour and mass dilution of the feed with water vapor 1: 2 ... 3.

Losses of alkali metal were determined through relative resistance to leaching.

The test data of the catalyst are shown in table 1.

Example 2

The catalyst is prepared and tested analogously to example 1, but instead of magnesium oxide, calcium oxide is used, instead of potassium carbonate, potassium hydroxide is used. Data on the composition (based on oxides) and the test of the catalyst are shown in the table.

Example 3

The catalyst is prepared and tested analogously to example 1, but strontium carbonate is used instead of magnesium oxide, rubidium nitrate is used instead of cesium carbonate. Data on the composition (based on oxides) and the test of the catalyst are shown in table 1.

Example 4

The catalyst is prepared analogously to example 1, but it is tested in the dehydrogenation reaction of isopropylbenzene to α-methylstyrene at a temperature of 560 ... 620 ° C, a flow rate of liquid isopropylbenzene of 0.5 ... 1.5 l / l of catalyst per hour and mass dilution of the feedstock with steam 1: 3 . Data on the composition (based on oxides) and the test of the catalyst are shown in table 1.

Example 5

The catalyst is prepared and tested analogously to example 1, excluding europium oxide. Data on the composition (based on oxides) and the test of the catalyst are shown in table 1.

Achievable technical result consists in obtaining a new catalyst that provides high catalytic activity and resistance to the action of catalytic poisons, and reducing its cost.

Claims (2)

A catalyst for the dehydrogenation of alkyl aromatic hydrocarbons, including oxides or compounds of iron, potassium, cesium and / or rubidium, magnesium and / or calcium, molybdenum, samarium oxide and Portland cement, which are decomposed to oxides, characterized in that it further comprises europium oxide in the following ratio of components, wt.% (in terms of oxides): Potassium oxide 8-22 Magnesium Oxide and / or Calcium Oxide 0.5-10 Molybdenum oxide 0.5-5 Portland cement 5-10 Samaria oxide 0.3-1.5 Europium oxide 0.005-0.030 Cesium oxide or rubidium 0.05-1.50 Iron oxide Rest