DE2049809A1 - Hydroxy-diphenyl synthesis catalyst - Google Patents

Abstract

Dehydrogenation catalyst, used in the mfr. of hydroxydiphenyl is prepd by (1) preparing a catalytic mass contg. Ni, Cr, Al and Cu as their carbonates, chromates or hydroxides in ratio 40-60:6.8-17.1:1.6-8.0:0.05-1.0, (2) impregnating this mass with an alkaline sulphate or carbonate soln so that alkali metal to Ni ratio is 0.6-3.4:40-60, (3) moulding this mass to give pellets of density 0.8-1.6 g/ml and (4) reducing the pellets in two stages, firstly heating at 350-420 degrees C with twice the H2 reqd. to reduce the Ni and also the Cr in 1-4 hrs. leaving the pellets for at least a week and then treating with 2-10 times H2 reqd. to reduce the Ni. With this catalyst high yields of hydroxydiphenyl are obtd. over long period of time.

Description

Process for the production of a catalyst for the synthesis of Hydroxydiphenyl According to German patent 1 108 221, 2-hydroxydiphenyl can be used obtained by dehydrogenating cyclohexylidenecyclohexanone on one with carbon dioxide treated nickel catalyst deposited on chromium or / and aluminum oxide, which still contains additives of alkali oxides, copper or silver.

However, it was found that the effectiveness of such a nickel catalyst after a short reaction time subsides and in addition to 2-hydroxydiphenyl to an increasing extent 2-Cyclohexylphenol is formed, which is the technical use of the catalyst in Paths is there, especially since its activity by burning with air and subsequent reduction can only be increased again for a short period of time.

Another disadvantage of the dehydrogenation process described in the patent consists in the suppression of dehydration processes that lead to Formation of diphenyl lead to about 15 mol of water must be added, which is a partial hydrolytic decomposition of cyclohexylidenecyclohexanone sur Polge.

To avoid this existing for the hydroxydiphenyl production Disadvantages of the catalytic I) hydrogenation of compounds and / or compound gels, which from completely or / and partially hydrogenated hydroxydiphenyl, the present invention therefore relates to a process for the production of Nickel, chromium, aluminum, copper and alkali sulfate or / and containing alkali carbonate Dehydrogenation catalysts with improved properties. One assumes one Nickel, chromium, aluminum and copper-containing catalyst matrix au that known methods, e.g. by joint precipitation from a nickel, An aqueous solution containing chromium, aluminum and copper nitrate using sodium hydroxide solution, e.g. according to German patent publication No. 889 591. The chrome compound can also be used, for example, in hexavalent form (see e.g.

Handbook of Catalysis Vol. VII, 1st half, p. 674 or

Houben-Weyl, Vol. 4/2, p. 179) use and instead as a precipitant Use caustic soda, e.g. ammonia, alkali carbonates or alkali hydrogen carbonates (see Houben-Weyl, Vol. 4/2, p. 137 ff .; Handbuch der Katalyse, Vol. V, Het.Kat. II, s 412 ff.). Depending on the precipitation conditions, i.e. depending on the precipitant used, The nickel falls in the pH value of the solution and the type of chromium compound used e.g. as hydroxide, as basic carbonate (see e.g. Gmelin, 8th edition, part B, Run 3, Syet. No. 57 (1966), pp. 846-853) or also as ammonium nickel chromate (see Gmelln, 8th ed., Part B, Lief. 3, Syst. No. 57, pp. 1215-1216). One possible variant for the production of the catalyst base material consists, for example, in the fact that one Nickel, aluminum and copper salt solution with alkali carbonate solution a carbonate-hydroxide mixture fails and this fact of washing out with ammonium dichromate at elevated temperature umeetst.

This catalyst base material is expediently before the deformation, so impregnated with alkali sulfate or alkali carbonate that the proportions of the alkali metals to the metals nickel, chromium, aluminum and copper, about 0.65 to about 3.4, preferably about 0.95 to about 2.8, to about 40 to about 60 to about 6.8 to about 17.1 to about 1.6 to about 8.0 to about 0.05 to about 1.0 be.

Nickel-chromium-copper catalysts containing alkali sulphate are already present for other dehydration processes, e.g. for the production of phenol from cyclohexanone and cyclohexanol (U.S. Patents 2,588,359 and 2,640,084 and Ind. Engng. Chem. 44, 1696 (1952)), but apart from the fact that these catalysts already in their gross composition and structure of the catalysts described above It is well known from catalytic practice that the transfer very special conditions of one procedure to another procedure not without further is possible.

In this case, two things emerged: WPhenol catalysts "der are completely unsuitable for the production of hydroxydiphenyl (see Example 8).

Alkali salt additives to other nickel-chromium-copper resp.

Nickel-chromium-aluminum-copper catalysts work on their own still no significant improvement in their mode of action. (e.g. catalyst A in example 1 and 4 or catalyst C in example 2 and 5) In addition to the gross composition of catalysts are way of catalyst deformation and reduction of equally decisive influence on the selectivity and life of the catalyst.

The catalyst deformation is expediently carried out on tablet presses according to the invention carried out so that the bulk density of the catalyst tablets between about 0.8 and about 1.6 g / ml, especially between about 0.9 and about 1.4 g / ml. Tableting can be carried out one or more times. Tablet sizes with a diameter of up to about 3 fl are generally used with simple tableting; For larger tablets, double tableting is used to recommend.

The reduction of the catalyst should take place eo that the content of metallic nickel in the finished catalyst between about 10 and about 35% by weight lies.

Particularly effective and long-lasting catalysts are obtained when the reduction is carried out in two stages, with the first stage of the reduction with about half to double that for the reduction of the nickel compounds metallic nickel and optionally the chromium (IV) compounds to form compounds of the trivalent chromium calculated, equivalent amount of hydrogen within one to four hours, the second stage of the reduction, on the other hand, preferably in time At least 1 week apart, with about two to ten times the ilir reduction of the nickel compounds of the catalyst to metallic nickel calculated equivalences Amount of hydrogen within the same period at temperatures between about 350 ° and about 420 ° C, preferably between about 370 ° and 390 ° C.

The present invention accordingly provides a method of production of nickel, chromium, aluminum, copper and alkali sulfate and / or containing alkali carbonate Dehydrogenation catalysts, characterized in that one is known per se One of the metals nickel, chromium, aluminum and copper, preferably as carbonates or / and chromates and / or hydroxides-containing catalyst base is produced in such a way that that the proportions of the metals mentioned like about 40 to about 60 to about 6.8 to about 17.1 to about 1.6 to about 8.0 to about 0.05 to behave about 1.0, this catalyst base, preferably before deformation, so impregnated with alkali sulfate or dipical carbonate that the xengen ratio of the alkali metals to nickel from about 0.65 to about 3.4, preferably from about 0.95 to about 2.8 to about 40 to about 60, the impregnated catalyst mass then into shaped bodies with a bulk weight of about 0.8 to about 1.6 g / ml, in particular of about 0.9 deformed to about 1.4 g / ml, the resulting shaped catalyst pieces initially with about half to double that for the reduction of nickel compounds to metallic ones Nickel and possibly the chromium (VI) compounds to form compounds of the trivalent Chromium's calculated, equivalent amount of hydrogen within one to four hours reduced and later one to four hours with about two to ten times the for the reduction of the nickel compounds of the catalyst to metallic nickel calculated, equivalent amount of hydrogen up to a content of the catalyst of metallic nickel further reduced from about 10 to about 35 wt .-%, wherein between the two reduction stages, preferably a storage of the catalyst of switches on for at least one week.

If the catalyst mass is tabletted twice, the first stage should be the reduction after the first tabletting, the second stage after the second tabletting take place.

The first stage of the reduction has expediently in this Case to connect an immunization of the catalyst. One leads to it in the usual way Transfer either ammonia and carbon dioxide one at a time, or very dilute air the catalyst.

An aging of the catalyst, e.g. with Connect carbon dioxide at 1000C or e.g. with very dilute air at room temperature. However, it is also sufficient to pass most of the hydrogen adsorbed on the catalyst To displace nitrogen or carbon dioxide.

The catalyst prepared according to the invention is particularly suitable for the synthesis of hydroxydiphenyl by catalytic dehydrogenation of compounds and / or mixtures of compounds consisting of completely and / or partially hydrogenated hydroxydiphenyl exist.

The catalyst to be used according to the invention stands out here over known ones, e.g. that of the German patent specification 1 108 221, by the following Advantages from: The service life of the new catalytic converter is increased many times over. The catalyst works even in the absence of water and even after a long period of time Operating time very selective in terms of dehydration. The dehydrating influence is greatly weakened.

The new catalyst can easily be regenerated by simple rinsing with a solvent at an elevated temperature, e.g. with Phenol at 170 ° C.

This is a significant improvement in the effectiveness of the catalytic converter in particular due to the combined influence of the addition of alkali salts, on the type of reduction conditions used and on the specific type of catalyst deformation. The nature and extent of this influence were surprising and unforeseeable.

Suitable starting materials for the use according to the invention Catalysts for the production of hydroxydiphenyl are for example: 2-cyclohexylidenecy lohexanone 2-Cyclohexenylcyclohexanone 2-CyclohepyScyclohexanone 2-Cyclohexylcyclohexanol 2-cyclohexylphenol 3-cyclohexylphenol 4-cyclohexylphenol 2-phenylcyclohexanone 2-phenylcyclohexanol.

The compounds mentioned are easily accessible. For example, this is how you get 2-: yclohexylidenecyclohexanone and 2-cyclohexenylcyclohexanone by condensing Cyclohexanone in the presence of acidic or basic catalysts by known methods These two compounds are also formed in addition to 2-cyclohexylcyclol xanone and 2-cyclohexylcyclohexanol e.g. as by-products in the catalytic cyclohexanol dehydrogenation. You can easily separated by distillation from the dehydrogenation mixture and used as a mixture for 2-hydroxydiphenyl production be used.

Cyclohexylphenol is obtained by known catalytic methods Phenol alkylation; 2-Cyclohexytphenol also occurs alongside 2-phenylcyclohexanone and 2-phenylcyclohexanol, 2-cyclohexylcyclohexanol and 2-cyclohexylcyclohexanone as a by-product in the 2-hydroxydiphenyl synthesis. All named connections can be fed back into the process.

In doing so, these pass through in vapor form individually or as a mixture with one another at temperatures from about 3000 to about 4000C, especially from about 3200 to about 3500C under normal pressure or reduced pressure over the catalyst.

In this way, at a space velocity over the catalyst of about Oo2 to about 0.4 g of starting product per ml of catalyst and hour at normal pressure, e.g. from the for the 2-hydroxydiphenyl production suitable starting compounds in addition to about 88 % By weight of 2-hydroxydiphenyl about 7 to 5% by weight of the abovementioned reusable substances Compounds so that the catalyst selectivity is above 90%. The hydroxydiphenyl component falls under the production conditions in 1000 hours usually no more than 3-5 in the event of a corresponding increase in the recyclable content. Under working conditions, where the evaporation of the starting product in the upper part of the furnace itself is carried out, the decrease in activity occurs as a result of increased deposition of resinous Connections on the catalyst naturally a little faster.

After the hydroxydiphenyl content has dropped to 60-70%, it is advisable to regenerate the catalyst by flushing with a solvent. this happens preferably with those indifferent to the catalyst under the rinsing conditions Solvents that boil about above 1300C, the catalyst temperature at least is set about 10 0C below the solvent boiling point. The flush can e.g. be carried out in such a way that the solvent flows through continuously from above the furnace is pumped, or e.g. so that the furnace is discontinuous several times in succession is filled with a new solvent each time. Suitable solvents are e.g. Xylene, cyclohexanol, phenol, diphenyl ether and dimeric condensation products of Cyclohexanone.

Regenerations of this kind can be used if there is a renewed decline in activity of the catalyst can be applied repeatedly.

After purging, the catalyst is brought to operating temperature in a stream of nitrogen heated up and ready for use again.

The hydroxydiphenyl produced by the claimed process has already found w wht; .ge areas of application, see B. as a preservative for citrus fruits or as a carrier for dyeing with disperse dyes.

Example 1: 357.5 parts by weight of a 38.5% by weight nickel, 7.5% by weight Chromium, 1.8% by weight of aluminum and 0.4% by weight of copper-containing catalyst base, which in a manner known per se by precipitating one of the elemen-te nickel, aluminum and copper-containing carbonate-hyflvoxide mixture from an aqueous solution of the appropriate nitrates using sodium carbonate solution and subsequent reaction of the precipitate washed beforehand with ammonium dichromate solution slurried with a solution of d.l parts by weight of potassium sulfate in 330 parts by volume of water. The contact paste obtained is then dried at 120 ° C., ground, with 3% graphite mixed and shaped into 2.4 mm tablets on an eccentric press.

The tablets are 2 1/2 hours at 390 ° C with 100 parts by volume Treated hydrogen per part by weight of tablets and hour.

Some of the reduced tablets are exposed to electricity for 30 hours 100 ° C heated: catalyst A: bulk density: 1.36 g / ml specific surface: 130 m2 / g Ni (metall.): 8.6% Ni (total): 49.5% Another part of the reduced tablets is after 3 weeks of storage for 2 1/2 hours at 390 ° C with 760 parts by volume of hydrogen treated per part by weight of tablets and hour and then treated for 30 hours in the 002 stream heated to 100 ° C.: catalyst B: bulk weight: 1.30 g / ml specific surface area: 130 m2 / g Ni (metall.): 13.7%, Ni (total): 51.7% In this and the following Examples are parts by weight to parts by volume in the ratio of g to ml.

Example 2: 357.5 parts by weight of a 38.2% by weight nickel, 8.9% by weight Chromium, 3.2% by weight of aluminum and 0.2% by weight of copper-containing catalyst base, are treated with a solution of 9.4 parts by weight of potassium sulfate in 330 parts by weight of water slurried.

The catalyst slurry is then dried at 120.degree. C. and after the Mahle @ formed into 2.4 mm tablets in the usual way.

The tablets thus obtained are 2.5 hours at 39,000 with 100 parts by volume Treated hydrogen per part by weight of tablets and hour.

Some of the partially reduced tablets are in a stream of CO2 for 50 hours heated to 100 ° C.: catalyst C: bulk density: 1.31 g / ml specific surface area: 120 m² / g Ni (metall.): 4.6% Ni (total): 47.2%.

Another part of the partially reduced tablets becomes after 3 weeks Storage for 2.5 hours at 3900C with 760 parts by volume of hydrogen per part by weight of tablets and treated for one hour and then heated for 30 hours in a stream of CO 2 at 100 ° C.: catalyst D: bulk density: 1.28 g / ml specific surface area: 115 m2 / g Ni (metallic): 12.1%, Ni (total): 49.4%.

Example 3: 12870 parts by weight of the catalyst matrix of the example 2 with a solution of 337.5 parts by weight of potassium sulfate in 11700 parts by weight Mixing water, drying and grinding.

Part of this catalyst mass is mixed with 1.5% graphite and formed into 5 mm tablets under relatively low compression pressure. The tablets are 2 1/2 hours at 380 ° C. with 100 parts by volume of hydrogen per part by weight of catalyst and hour treated and then heated for 30 hours in a stream of C02 at 1000C: catalyst E: bulk density: 0.84 g / ml Ni (metall.): 12.6%, Ni (total): 52.4,.

Part of the catalyst E is used for a further 2.5 hours at 3900C 1200 parts by volume of hydrogen per part by weight of catalyst E per hour treated: Catalyst F: bulk density: 0.85 g / ml Ni (metallic): 26.2%, Ni (sat.): 52.7%.

Another part of the catalyst mass is mixed with 1.5% graphite and formed into 5 mm tablets under moderate compression pressure. The tablets are first 2 1/2 hours at 3900C with 100 parts by volume of hydrogen per part by weight of catalyst and hour and then 2.5 hours at 3900C with 725 parts by volume of hydrogen Treated per part by weight of catalyst and hour and then at 100 ° C for 30 hours Annealed in a C02-Stroi: Catalyst G: bulk density 0.90 g / ml Ni (metal.): 24.8 %, Ni (total): 52.4%.

A further part of the catalyst mass is as in the production of the catalyst G processed, only with the difference that the tablets after the first part of the reduction is treated successively with NH3 and C02 at room temperature, then ground and again with 3% graphite under moderate pressure tabletted : Catalyst H: bulk density: 0.94 g / ml Ni (metal.): 27.4, Ni (total): 51.2 .

Two more parts of the catalyst mass are used as in the manufacture of the catalyst H processed, only with the difference that the second tableting takes place under increasing pressure: Catalyst I: bulk density: 1.14 g / ml Ni (metall.): 22.4 X, Ni (sat.): 49.5% Catalyst K: bulk density 1.20 g / ml Ni (metall.): 26.6%, Ni (total): 51.6% Another part of the catalyst mass is as with the Production of the catalyst I processed, only with the difference that for the Immunization of the catalyst instead of NH3 and C02 a mixture of 2 vol .-% air and 98% by volume of CO2 is used: Catalyst L: Bulk weight: 1.12 g / ml Ni (metallic): 22.0% (sat.): 49.9 96.

Another part of the catalyst mass is used as in the manufacture of the catalyst I processed, only with the difference that instead of the final Aging with CO2 at 1000C a 12-hour treatment with a mixture of 2% by volume Air and 98 vol .-% CO2 at room temperature takes place: Catalyst M: bulk density: 1.12 g / ml Ni (metall.): 21.5 ", Ni (total): 50.1%.

Another part of the catalyst mass is used as in the manufacture of the catalyst I processed, only with the difference that the second part of the Reduction takes place at 3700C: Catalyst N: Bulk weight: 1.10 g / ml Ni (metall.): 19.2% Ni (total): 49.4%.

Example 4 In a tubular reactor with a tube diameter of 17 mm, the upper part of which is used as an evaporation zone and the lower part is filled with 30 parts by volume of the catalyst B prepared according to Example 1, 6.0 parts by weight of a mixture of 97 parts by weight of 2-cyclobexenylcyclohexanone are per hour and 2-cyclohexylidenecyclohexanone, 2.5 parts by weight of 2-cyclohexylcyclohexanone and 0.5 part by weight of cyclohexanone metered in. The catalyst temperature is thereby held at 330 ° C.

After a start-up period of a few hours, you get per hour 5.7 parts by weight of reaction product, 83% of which consists of 2-hydroxydiphenyl, of 7% 2-Cyclohexylphenol, 3.5% from diphenyl, 6% from diphenylene oxide and 0.5% % consists of phenol; this corresponds, taking into account the reusable Cyclohexylphenol content with a selectivity of 90.5%.

After an operating time of 1500 hours, the reaction mixture settles to 66% 2-hydroxydiphenyl, 24% 2-cyclohexylphenol, 4% 2-cyclohexylcyclohexanone, 3.5% diphenylene oxide, 1% diphenyl and 0.5% phenol combined; that corresponds to a Selectivity of 94.5%.

If instead of the catalyst B the one prepared according to Example 1 is used Catalyst A and proceed as above, ao is obtained at the beginning of experiment ii Reaction mixture 81% 2-hydroxydiphenyl, 6% 2-cyclohexylphenol, 7% diphenylene oxide, 4% diphenyl, 0.5% phenol and 1.5% lower-boiling precursors.

After an operating time of only 320 hours, the 2-hydroxydiphenyl content is dropped to 53% in the reaction mixture.

In addition, 26% 2-cyclohexylphenol, 8% diphenylene oxide, 6 % 2-cyclohexylcyclohexanone, 2% diphenyl, 2% cyclohexenylcyclohexanone, 0.6% phenylcyclohexanone, 0.6% phenol and 1.8% lower-boiling by-products.

Example 5: Over 30 parts by volume of that produced according to Example 2 Catalyst D are placed in a tubular reactor (inner tube diameter: 17 mm) Maintaining a contact temperature of 3300C per hour 6.0 parts by weight of the example 4 used starting product passed in vapor form.

After a short start-up time, the reaction product is approx. 5.7 parts by weight of a mixture consisting of 85% 2-hydroxydiphenyl, 5% 2-cyclohexylphenol, 0.5% 2-cyclohexylcyclohexanone, 5.5% diphenylene oxide, 3.5% diphenyl and 0> 5 % Consists of phenol; this corresponds to taking into account the reusable Compounds with a selectivity of 91 s.

After an operating time of 1450 hours, the reaction mixture has the following composition: 65% 2-hydroxydiphenyl, 20% 2-cyclohexylphenyl, 5% 2-cyclohexylcyclohexanone, 1,3, 2-cyclohexenylcyclohexanone and 2-cyclohexylcyclohexanol, 6th % Diphenylene oxide, 2% diphenyl, 0.5% phenol and 0.7% low-boiling precursors; taking into account the reusable connections, this corresponds to a Selectivity of 92 96.

The furnace temperature is lowered to 2000C to rinse the catalyst. Then 100 parts by weight of the starting product are added per hour for 2 hours used mixture is pumped liquid over the catalyst. The furnace is then in a stream of nitrogen heated to 3300C and used again for dehydration.

The resulting dehydrogenation mixture consists of 72% 2-hydroxydiphenyl, 17% 2-cyclohexylphenol, 3.0% 2-cyclohexylcyclohexanone, 0.8% 2-cyclohexenylcyclohexanone and 2-cyclohexylcyclohexanol, 4.6% diphenylene oxide, 1.6% diphenyl and 1.0% phenol and lower-boiling intermediate products.

After a total operating time of 2700 hours, the 2-hydroxydiphenyl content is dropped to 60% in the reaction mixture. Another rinse is performed. This is done for 6 hours per hour after lowering the oven temperature to 1700C 100 parts by weight of liquid phenol is pumped over the catalyst. Then the The furnace was heated up again to 3300C in a stream of nitrogen and started up again.

The 2-Hydroxydiphenylg.halt ii reaction mixture is through the rinsing process increased to 70%.

After an operating time of 3300 hours, a new rinse takes place with phenol, which at the same time increases the contact temperature to 350 ° C the 2-hydroxydiphenyl content in the reaction product increases from 60 to 78%.

After an operating time of 4100 hours is under these conditions the 2-hydroxydiphenyl content only dropped again to 68%.

If instead of the catalyst D the one prepared according to Example 2 is used Catalyst C and proceeds as described at the beginning of the example, so falls the 2-hydroxydiphenyl content in the reaction gel in the first 160 hours of operation from 81% to 58%. The content of by-products that cannot be reused is during this time 11 to 12, '.

EXAMPLE 6 6.0 parts by weight of the starting material used in Example 4 are passed in vapor form every hour over 30 parts by volume of the catalysts prepared according to Example 3 in a tubular reactor (internal tube diameter: 17 mm) at a catalyst temperature of 330 ° C. The following results are obtained: Catalyst operating reaction products selective hour of 2-hydroxy re-unity Diphenyl settable compounds (X) bond (%) *) 11. 84 11 94 280. 55 35 85 F 57. 81 12 92 280, 62 30 89 G 33. 82 11 92 280. 66 26 89 H 80.82 10 91 800. 67 27 92 Catalyst operating reaction products selective hour of 2-hydroxy re-unity diphenyl settable (%) (%) bond (%) *) I 70. 84 7 90 800. 66 28 92 I 75. 83 9 92 800. 66 27 90 M 75. 84 8 91 800. 65 29 91 N 60. 82 9 90 800. 65 28 90 *) This group includes the following compounds 2-cyclohexylphenol, 2-phenylcyclohexanone, 2-phenylcyclohexanol, 2-cyclohexenylcyclohexanone, 2-cyclohexylidenecyclohexanone, 2-cyclohexylcyclohexanone, 2-cyclohexylcyclohexanone, example 7: Over 7000 parts by volume of the catalyst K. are in a tubular reactor of 400 ca length and a tube diameter of 50 - at a catalyst temperature of 330 to 3400C hourly 1800 parts by weight of a mixture that consists of 99.2, of 2-cyclohexenylcyclohexanone and 2-cyclohexylidenecyclohexanone and 0.8% consists of cyclohexanone and cyclohexanol, passed in vapor form. The following results are obtained Operating 2-hydroxy reaction product recycled hour diphenyl precursors Diphenyl bare compound (%) Cyclohexanol, diphenylene - see example Cyclohexanone, oxide (X) Phenol etc.) (X) (%) 180. 88 @ 8 3 500. 86 1 7 6 720. 85 1 9 5 1000. 84 1 8 7 1400. 83 1 6 8 1600. 82 1 8 9 2400. 70 1 8 21 EXAMPLE 8 Over 30 parts by volume of a catalyst prepared according to Example 1 of US Pat. No. 2,640,084 are in a tubular reactor (tube diameter: 17 mm) at a catalyst temperature of 3300 ° C. per hour 6.0 parts by weight of the starting material used in Example 4 passed in vapor form.

The following result is obtained: Operational 2-Hydroxy Reaction Products Again Selek. hour diphenyl precursors Diphenyl insert- tivi Cyclohexanol, Diphenylbar Verit Cyclohexanone, oxide bond (%) Phenol etc.) (%) (%) (%) l.-16. 51 19 14 16 61 17.-40. 30 18 11 41 51 Example 9: Over 30 parts by volume of the catalyst K prepared according to Example 3, which is located in a tubular reactor according to Example 4, 6 parts by weight of vaporous 4-cyclohexylphenol are passed every hour at 330.degree. After a shorter start-up period, 4-hydroxydiphenyl is obtained as the main reaction product. Its proportion, in general, of the reaction mixture, after an operating time of 550 hours in contact, is consistently about 56%.

Claims (4)

Patent claims: 1. Process for the production of nickel, chromium, aluminum, copper and dehydrogenation catalysts containing alkali sulfate and / or alkali carbonate, characterized in that (a) one of the metals in a manner known per se Nickel, chromium, aluminum and copper, preferably as carbonates and / or chromates or / and containing hydroxides and alkali metals as sulfates and / or carbonates Produces catalyst composition so that the proportions of the metals mentioned such as about 40 to about 60 su about 6.8 to about 17.1 to about 1.6 to about 8.0 su about 0.05 to about 1.0 to about 0.65 to about 3.4 behave (b) this catalyst composition then see below porous bodies with a bulk density of about 0.8 to about 1.6 g / ml, in particular from about 0.9 to about 1.4 g / l deforms (o) the shaped catalyst pieces obtained Temperatures between 35,000 and 42,000 initially with about half to double that for the reduction of the nickel compounds to metallic nickel and optionally the chromium (VI) compounds to compounds of trivalent chromium calculated, equivalent amount of hydrogen reduced within about one to four hours and (4) later with about two to ten times that for the reduction of the nickel compounds of the catalyst su metallic nickel calculated equivalent amount of hydrogen within about one to four hours to a content of the catalyst metallic nickel further reduced by about 10 to 35% by weight. 2. The method according to claim 1, characterized in that the Process stage (d) is carried out at the earliest one week after process stage (c). 3. The method according to claim 1, characterized in that the Catalyst immunized in a manner known per se after process step (c), pays and again su moldings with a bulk density of about 0.8 to about 1.6 g / ml deformed and then process step (d) follows. 4. Use of a catalyst prepared according to Claims 1 to 3 for the production of hydroxydiphenyl by catalytic dehydrogenation of compounds and / or mixtures of compounds which consist of wholly and / or partially hydrogenated hydroxydiphenyl exist.