DE1108221B - Method for controlling the mode of action of dehydrogenation catalysts for hydroaromatic compounds - Google Patents

Description

It is known to use hydrogenation catalysts with metals of the iron group of the Periodic Table, those with metal oxides of III. and VI. Group of the periodic system can be associated, also as dehydrogenation catalysts for aliphatic and especially hydroaromatic compounds use. However, the dehydrogenation temperatures must be significant for thermodynamic reasons higher than in the hydrogenation. Polynuclear or substituted cycloaliphatic compounds but can easily at these temperatures in the presence of the catalysts mentioned be split.

It has now been found that the mode of action of highly active catalysts for dehydrogenation hydroaromatic compounds in the vapor state, the nickel on aluminum oxide or or and chromium oxide contained in a technically simple manner by treating with carbon dioxide at higher levels Temperatures in accordance with the respective technical requirements slightly in very specific Direction can be steered. So you can use this method to determine the mode of action of the catalyst readily predetermine in such a way that it is both a dehydrogenation of functional groups on the hydroaromatic Core as well as, usually at higher temperatures, a dehydration on the Kern itself causes without any noteworthy cleavage occurring.

The catalysts controlling their mode of action according to this process can, in addition to nickel, aluminum oxide and chromium oxide or surcharges, e.g. B. alkali oxides, such as potassium oxide, copper or silver, contain.

The temperatures required to control the mode of operation of the catalytic converter can fluctuate within wide limits. Good results are generally obtained at temperatures between about 70 and 200 ° C and in particular between about 90 and 12O ⁰ C. The duration of the heat treatment of the catalyst with carbon dioxide depends on the particular nature of the particular catalyst present and on the desired degree of selectivity. For most practical needs, this treatment time is between about 20 and 100 hours, and especially between about 50 and 70 hours. In addition, the required duration of treatment can easily be determined in individual cases by means of a simple experiment.

With the aid of the catalysts produced by the present process, hydroaromatic Compounds of various kinds are dehydrated methods of directing the mode of action

of dehydrogenation catalysts
for hydroaromatic compounds

Applicant:

Paint factories Bayer Aktiengesellschaft,
Leverkusen

Dr. Gustav von Schuckmann, Krefeld,

and Dr. Helmut Hanisch, Krefeld-Bockum,

have been named as inventors

be, so z. B. cyclohexane, tetrahydronaphthalene, DekahydronaphthaÜn, dicyclohexyl and in particular Cyclohexylidenecyclohexanone and 3,4-dimethylphenylcyclohexane.

The conversion of cyclohexylamine into a mixture of cyclohexanone and cyclohexanol in The presence of water, a process that is initiated by dehydration, can be used to advantage Using the present dehydrogenation catalysts are carried out.

The dehydrogenation temperatures are mostly between about 150 and about 400 ° C., in particular between around 250 and 350 ° C.

example 1

Via a pelletized catalyst, which contains nickel deposited with the addition of copper on aluminum oxide and chromium oxide and which, after the hydrogen reduction carried out at 3 80 ° C, has a composition of about 67% Ni, 0.4% Cu, 6% Al ₂ O ₃ and 26 % Cr ₂ O ₃ , a stream of dry carbon dioxide is passed at 100 ° C. for 60 hours. It is then slowly cooled to 20 ° C. in a stream of carbon dioxide over a period of 50 hours.

The effect of the catalytic converter adjusted in this way to a certain mode of operation results from the subsequent attempts:

A. One passes over 11 of the catalyst treated in this way and slowly heated to 260 ° C. under hydrogen a steam mixture under normal pressure at 260 ° C, the 9.1 percent by volume of cyclohexylamine and to 90.9 percent by volume consists of water. The steam

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Claims (1)

3 4 speed is set so that carbon dioxide has been treated every hour, carried out so 500 parts by weight of cyclohexylamine via the catalyst are also obtained in 7 hours, also 210 parts by weight stream. Reaction product, which after work-up with From 500 parts by weight of cyclohexylamine, 63 parts by weight of o-oxydiphenyl = 39.2% of alkali are obtained in this way give 5 theory in addition to 3.5 parts by weight of phenol. 333 parts by weight of cyclohexanone ^from << L ^em . ^{SfFf 10} * (135 parts by weight) = 67 2 ° / of theory in addition to 5 parts by weight of benzene and 37 parts by weight and only 37 ^{parts by weight of cyclohexanol Ha} ^ ⁹³ parts by weight of distillate with a ketone number of 45 = 7.3 »/ or theory received. Contains traces of phenol in addition to 20 parts by weight - ¹⁰ Example 2 = 4 5 ° / the theory A weakly alkalized, tableted Ni-Cu-Al ₂ O ₃ - 73.3 parts by weight of cyclohexylamine Cr ₂ O ₃ -K ₂ O catalyst, which is produced by dry = 14 6 ° / the theoretical mixture of 90 parts by weight of alumina and 23.8 ^{parts by weight of dicyclohexylamine 1} ^ Ni-Cu chromate with 10 parts by weight of a calcined Mixture of Al ₂ O _{3 -Cr 2} O ₃ -K ₂ O has been prepared _Hydrogen reduced. The last two products can start the reaction. The catalyst is then left for at least 60 hours be fed back. treated in a stream of carbon dioxide at 100 °. If the dehydrogenative aminolysis falls below the 20, the catalyst then has the following composition: same conditions with the same but not Ni = 47%; Cu = 0.28%; Al = 7.5%; Cr = 14.3%; Catalyst treated with carbon dioxide in the heat- K ₂ O = 0.2% carried out sator, then from 500 parts by weight of A. About 100 ecm of in the manner indicated above Cyclohexylamine obtained: prepared catalyst is in a furnace . "". ,. . ., _,,, 25 temperature of 300 ° C 3,4-dimethylphenylcyclohexane 252 parts by weight of cyclohexanone passed. The steam speed is , _n ~ . l ° _{t for} ? ^e h 1 provided that every hour 20 parts by weight of 3,4-dimethyl Parts by weight of cyclohexanol phenylcyclohexane flow over the catalyst. In u η ÖV- · ί \ + · \ ^ ° ^Π ι \ ι ■ 5 hours, 96.5 parts by weight of conversion in addition to 12.8 points by weight of cyclohexylammine ₃₀ product was obtained. ΤΪ ⁷ ITT ?? ^e i fi ηΤΪ ⁷ ItT-T ?? ^e , u ! - The processing results:
and 30.4 parts by weight of dicyclohexylamine = 6.6% of theory. 88.3 parts by weight of 3,4-dimethyldiphenyl α π α ** i, -U ₊ -A ■ + = 91.5% of theory, In addition to not use again arise _{l4 percent} i _ch tsteile diphenyl capable connections: 35 ₌ 1.5 ° / ₀ of theory, 65.8 parts by weight of cyclohexylidenecyclo- 6.2 parts by weight of 3,4-dimethylphenyl- hexanone cyclohexane = 14.6% of theory, = 6.5% of theory. 30.7 parts by weight of phenol,., ._,., ..., - ^ _{n ,,, TT} 650 / of theory ^{4 ° parts by} weight = 75% of the 3,4-dimethyldiphenyl which crystallizes out of the reaction and 31.8 parts by weight of aniline product = 67 ° / of theory can be separated off immediately. The mother liquor, diluted with the starting compound, B. Over 100 ecm of the above, can be reused with coal. Dioxide treated and heated under hydrogen 45 B. Will the dehydration with the same, but not Catalyst is conducted at an oven temperature _{treated with CO 2} catalyst, so from 330 ⁰ C a tail boiling at 210 to 260 ° C under the same conditions in 5 hours mixture obtained from the distillation of the 93.5 parts by weight reaction product in the aminolysis. the of cyclohexylamine with water and in the Dehy work-up results in: dration of cyclohexanol to cyclohexanone an- 50 ^, _c ^. ,. ,. _{,, λ} ". , ,,. , falling sales product is obtained and the ⁶³ ' ⁶ parts by weight of 3,4-dimethyldiphenyl 80% o-cyclohexylidenecyclohexanone with a ketone, _ _ ~ ⁶ ° {»^ F ₁ ^T 5f. °" ^e ', contains number of 251. To the mixture 1.3% ^{18 '7} Gewchtsteile diphenyl Water added. The steam speed will be so. , ~. (° ., ^ ^E ° ^ f. '. ,, set that hourly 29.6 parts by weight of follow-up 55 ^1O ' ^J weight point 3,4-dimethylphenyl flow mixture over the catalyst. ^ i ^ o? ^ tu ■ 210 parts by weight of um- ~~ ⁿ / 0 of the iheones are obtained in 7 hours. Settlement product. This is done with diluted lye moved out. The work-up of the alkali-soluble PATENT CLAIM Parts gives 132 parts by weight of o-oxydiphenyl 60 = 82.5% of theory in addition to 4 parts by weight of phenol. Process for controlling the mode of action of From the neutral oil (64 parts by weight) are in addition to dehydrogenation catalysts for hydroaromatic 3 parts by weight of benzene and 21 parts by weight of resin compounds in the vapor state, characterized by 40 parts by weight of distillate with the ketone number 19.6 is characterized by the fact that the known, on chromium - and received. 65 or or aluminum oxide precipitated If the hydrogenation with the same, freshly with nickel catalysts in the heat with carbon-hydrogen reduced catalyst, which is not treated with dioxide. © 109 610/459 5.61