CS233167B3 - Dehydrogenation ferric catalyst with high selectivity - Google Patents

Abstract

The invention improves the activity and selectivity of the dehydrogenation iron catalyst according to Czech Patent Application No. 168 220 by adding 0.5 to 55 wt. % of compounds of elements from the group of lanthanum, praseodymium, ueodymium and samarium individually or their mixtures, calculated on their oxides. The catalyst is particularly suitable for the dehydrogenation of alkylaromatic and alkylheterocyclic substances to alkenylaromatic and alkenylheterocyclic substances and of olefins to diolefins.

Description

(54) Dehydrogenation iron catalyst with high selectivity

The invention improves the activity and selectivity of the dehydrogenation iron catalyst according to Czech Patent Application No. 168 220 by adding 0.5 to 55 wt. % of compounds of elements from the group of lanthanum, praseodymium, ueodymium and samarium individually or their mixtures, calculated on their oxides. The catalyst is particularly suitable for the dehydrogenation of alkylaromatic and alkylheterocyclic substances to alkenylaromatic and alkenylheterocyclic substances and of olefins to diolefins.

(51) Int. C1. ^J B 01 J 23/76 C 07 B 3/00

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The invention relates to a dehydrogenation iron catalyst with high selectivity according to Czechoslovak Patent Application No. AO 168 220, suitable for the dehydrogenation of alkylaromatic and alkylheterocyclic substances into alkenylaromatic and alkenylheterocyclic substances and olefins into diolefins.

The basic component of ferric dehydrogenation catalysts is ferric oxide, which changes during dehydrogenation to ferrous-ferric oxide. The presence of alkalis in the catalyst, which are the promoter of the catalyst's autoregeneration, of which the most commonly used are potassium salts, is also indispensable. Selectivity promoters are added to these basic substances, which can be, for example, boron compounds, as stated in the Czech patent.

No. 104,763, even more effective is the addition of vanadium compounds in combination with molybdenum or tungsten compounds and titanium dioxide, as disclosed in Czechoslovak Patent Application No. 168,220. It is also known to commonly add structural promoters to this type of catalyst, of which chromium compounds are the most commonly used, but in the case of using lanthanum or praseodymium or neodymium or samarium compounds or mixtures thereof according to the new invention, this is not absolutely necessary.

It has now been found that a catalyst with even greater selectivity and activity than that corresponding to the catalyst according to Czechoslovak Patent Application No. 168,220 is obtained if the catalyst according to Czechoslovak Patent Application No. 168,220 additionally contains compounds of elements from the group of lanthanum, praseodymium, neodymium and samarium individually or a mixture thereof. The improvement in selectivity and activity is particularly significant at higher conversions.

from

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According to the invention, a dehydrogenation iron catalyst with high selectivity according to AO No. 168 220, consisting in containing compounds of elements from the group of lanthanum, praseodymium, neodymium and samarium individually or mixtures thereof in an amount of 0.5 to 55% by weight, calculated as their oxides, based on the total weight of the catalyst.

Example 1

Pollen prepared catalyst according to the invention with this final composition:

La ₂ 0^ k ₂ o

This ₂

68.5 % wt. ^At 2°5 2 % mass 10 n wow ₃ 2 II 10 lt Cr ₂ °3 2 11 5 n At ₂ 0 0. >5 11

The diameter of the extrudates was 3 to 4. mm, length 5 to 7 mm. This catalyst was tested in a reactor for the dehydrogenation of ethylbenzene to styrene. The catalyst was tested in an isothermal stainless steel reactor with a diameter of 25/22 mm and a length of 1200 mm. 50 ml of catalyst was placed in the retort, to which 25 ml/h of ethylbenzene and 65 ml/h of water were fed. After passing through the reaction zone, the gases were cooled in a cooler and the condensed hydrocarbons were separated from the water. According to the chromatographic analysis of these hydrocarbons and the outgoing uncondensed gas and from their amount, the conversion to styrene and selectivity were calculated. The testing was carried out continuously for 100 h, with the first 50 h not taken into account. The reaction temperature was chosen so that the conversion to styrene was constant at 40% or 50% by weight. The testing results are shown in the table.

Example 2

A catalyst according to the invention was prepared with the following final composition:

and

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^®2θ3 31% by weight to ₂ ° 10 % wt. La^O^ 25.5” Ti0~ £ 5 11 Nd ₂ O ₃ 18.9” ^At 2°5 3 11 ^Pr 6°ll 4.5” Mo0 ₃ 1 at Sm^O^ 1.1” The test results are listed in table. Example 3 For comparison, according to Czech Republic AO No. 168 220, example No. 3, ready catalyst about this final composition: Pe ₂ O ₃ 81% by weight ^At 2°5 3 % wt. To ₂ 0 10 ” Mo0 ₃ 1 11 Ii0 ₂ 5 ’’

The testing results are shown in the table.

Table

Catalyst Example 1 according to Example 2 of the invention Ex. 3 according to AO 168220 Conversion to styrene % wt 40 40 40 Temperature °C 550 545 555 Selectivity % mol. 96.3 97.3 94.7 Conversion to styrene % wt 50 50 50 Temperature °C 568 563 575 Selectivity % mol. 95.4 96.4 93.3

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Claims (1)

SUBJECT OF THE INVENTION High selectivity iron dehydrogenation catalyst according to AO No. 168 220, characterized in that it contains compounds of elements of the lanthanum, praseodymium, neodyra and samarium groups individually or mixtures thereof in an amount of 0.5 to 55% by weight. calculated on their oxides based on the total weight of the catalyst.