DE1943362A1 - Process for making a nickel-on-silica catalyst - Google Patents

Description

DR. E. WIEGAND DIPL-ING. W. NIEMANN DR. M. KÖHLER DIPL-ING. C. GERNHARDT

MÖNCHEN HAMBURG

TELEPHONE, 555476 8000 MONKS 15.26 AUGUST 1969

TELEGRAMS: KARPATENT NUSSBAUMSTRASSE

W. H 423/69 7 / Never

Unilever N.V. Rotterdam (Netherlands)

Process for the preparation of a nickel-on-silica catalyst

The invention relates to a process for the preparation of a nickel-on-silica catalyst and especially a nickel-on-silica catalyst, which is suitable for the selective hydrogenation of glyeeride oils

Most fatty oils contain triglycerides in theirs poly-unsaturated acids in addition to mono-unsaturated acids. In the catalytic hydrogenation of such oils, a Number of competing reactions take place, some of which are undesirable as they lead to the formation of completely hydrogenated fats give rise to * those for food purposes are less suitable.

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By using appropriately selective catalysts, which are catalysts which promote one reaction while being inactive or much less active in other reactions, it is possible to substantially avoid the formation of undesirable by-products. It is known ■ that catalysts with nickel on supports, in particular. , Nickel-on-silica catalysts, are suitable for such selective hydrogenation, provided that they meet certain structural requirements. A very important factor in this context is the size of the pores of the supported catalyst ^. According to JWB Coenen, H. Boerma ,. BG Linsen and 3rd de Vries. in "Proceedings Third International Congress on Catalysis", Volume II (1965), p. I387, the selectivity of a nickel-on-silica catalyst is strongly dependent on the volume of the

• ο pores with a diameter of less than 25 A in relation.

depends on the total pore volume. The term "selectivity", as used in this context, the selectivity of a catalyst expressed by the dilation at 3O ⁰ C (D ^ ₀₎ (determined ■ as in HA Boekenoogen "Analysis and Characterization of Oils and Fat _: Products ", London, -New York, Sidney, (1964), volume: 1, p.144 * described), of a standard soybean oil understood / of which 100 g by means of this catalyst with a content of 0.2 g nickel under standard conditions ,, namely 100 ⁰ C and · 'of a V / asserstoffströmung of 60 l / h, to an iodine value (JZ) von.-90 - obtained 1', have been hydrogenated. In addition to being selective, such curing catalysts should also be active and resistant to poisons, because otherwise the amount to be added or during. of the hydrogenation process consumed too much catalyst

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becomes, which is not sustainable for economic reasons.
The latter two properties are also of the
Depending on the pore size distribution of the carrier, they are determined in particular by the size of the nickel particles present on the surface. In this context, an important property is the consumption of nickel. This term, as used in this context, is to be understood as the minimum amount of nickel (expressed in g) which is required to produce 100 g of a standard whale oil (with a sulfur content of J> 0 ppm) under standard conditions
(Hydrogenation time 8 hours, temperature 180 ° C, hydrogen flow 1 / hour) to cure to give a product with a refractive index of Nj ^ = 1.4 ^ uO.

Though numerous procedures and modifications thereof
have been described in the literature for the production of nickel-on-silicon dioxide catalysts, the industrial production of such catalysts with the desired
Properties have not yet been satisfactorily solved in a reproducible manner. One of the cheapest, and therefore probably the most widely used, is a process in which the nickel is extracted from an aqueous solution of a
Nickel salt in the form of its hydroxide and / or carbonate is precipitated onto the carrier material and the resulting composition is activated under reducing conditions.
A serious drawback of this procedure is
da.5 it is very difficult to produce a
Obtain a catalyst with a high specific
Nickel surface (surface of the nickel particles per g of nickel) is combined with an optimal pore size distribution.

BAD ORiSfNAl ₁
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It has now been found that "a nickel-on-silica catalyst can be prepared in which the requirements for selectivity, activity and resistance to poisoning are met in a very satisfactory and reproducible manner by using a process at the nickel hydroxide is precipitated from an aqueous solution of a nickel salt by an alkali hydroxide at a pH value between 7 and 10.5 * measured at 2O ⁰ C and a solid silicon dioxide catalyst support is added during or after the precipitation, a nickel hydroxide -Silica composition isomerized, washed and dried and subjected to an activation process by heating in the presence of hydrogen, the composition, before being dried, being subjected to a heat treatment with an aqueous solution of an alkali hydroxide having a pH between 11 and 13 * 5 and at a temperature between 50 and 120 ° C is subjected to a composition sizung, which after reduction with hydrogen for JO min at 45O ⁰ G in a hydrogen flow of 30 l / h. gives a catalytic material which gives a nickel consumption, as defined above, of less than 0.10 g and a selectivity, as defined above, of D ₀ <100.

In the above process, the heat treatment the "mixture of nickel hydroxide and silica containing Carrier material with aqueous alkali hydroxide is the critical one Step. Although the various other preceding stages do not, to a certain extent, affect the quality of the Although the resulting catalyst can be varied, a number of requirements must nonetheless be met.

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First, the use of alkali hydroxide as a precipitant in the first stage is essential because the process does not give the desired results when using alkali carbonate. It is known that nickel hydroxide can be precipitated at any pH value which exceeds a certain lower limit, but it is important that the pH value at which it is .precipitated is not too high, and it has been found that precipitation at a pH between 7 and 10.5 is essential to achieve a catalyst with the desired properties. Very good results are obtained if the nickel hydroxide is precipitated from aqueous nickel sulfate at a pH between 8 and 10. The pH value is preferably kept at a constant level during the precipitation, which means that the deviation does not exceed a value of -0.2 (NB The aforementioned pH values of the reaction mixture apply if they are at a temperature of 20 ⁰ C; the actual values at higher temperatures must be corrected accordingly).

Although the temperature at which the nickel hydroxide is precipitated is generally not critical, the precipitation is preferably ^{carried out at an elevated temperature, for example above 90 °} C., which is particularly important if nickel sulfate is used as the starting material.

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-ο -

The simplest, and therefore preferred method for .. 'Association of aqueous solutions of nickel salt, and. of the alkali hydroxide. consists in introducing the two solutions simultaneously with stirring into a mixing vessel while the above-mentioned pH value range is maintained within this vessel, which can very advantageously be achieved in an automatic manner by the extent of the · "" Adding one of the solutions with the pH of the mixture formed by means of a device known in the art couples * ■■ '■'

The silicon dioxide-containing carrier material can to added to the nickel hydroxide both during and after the precipitation. When the former is used is, care must be taken that no suspension of the silicon dioxide-containing material in the aqueous alkali hydroxide is formed before the latter solution with the aqueous. Solution of the nickel salt has been combined; the reason for this is that in such a suspension 3ilic.atio.nen were formed, "the at the subsequent union of the suspension and the. aqueous solution of the nickel salt for the precipitation of basic Nicke Is il-icat. Giving cause, -what. a disadvantageous one Effect on the quality of the catalyst finally obtained would have.." , .."...

A very simple and. -Effective way for! the addition of the support material to the nickel hydroxide consists in the The above-described method of combining the aqueous Solutions; of the nickel salt and of the alkali metal hydroxide

⁵ⁱ ^ ^{ί3 'v} 0098 IQ / 1536

and the carrier material simultaneously in the mixing vessel, either as such or in the form of a separate aqueous suspension or suspended in the aqueous solution of the Nickel salt.

The next stage, preparing the mixture from the freshly precipitated nickel hydroxide, the one containing silicon dioxide Carrier material and the aqueous alkali hydroxide with a pH between 11 and 135 can be in any suitable V. can be carried out gently. If in the first part of the procedure the preferred procedure described above for combining the support material with the nickel hydroxide is applied, the suspension obtained can be converted into the mixture with the required pH by two different methods, namely either the pH the suspension immediately to the desired value. Addition of concentrated aqueous alkali hydroxide ceased or the solids can be separated from the suspension and then with aqueous alkali metal hydroxide of a suitable one pH mixed \\ <ground to a mix with the required to achieve pH value «

The following Suufe, the heat treatment of the Mixture that has the desired pH and any the above procedures can be carried out again in various ways. Although a touch of the three components even if only weakly Elevated temperatures ultimately results in a catalyst with the desired properties, should be practical Execution of the contact time to an acceptable one

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Long are reduced, that is, the lower limit of the temperature at which the mixture is kept not to be under 5O ⁰ C significantly. On the other hand, due to the presence of water in the mixture, the upper limit of the temperature is about 100 ^° C. or only slightly above it. It would of course be possible to heat the mixture in a closed vessel under superatmospheric pressure so that a higher temperature could be reached, but an excessive increase in temperature has a disadvantageous effect on the pore structure of the carrier material!?, So that the desired effect is lost. For this reason, the upper limit of the temperature is about 120 ^° C.

If the mixture of a sufficiently thin mud or a sufficiently thin. If there is a suspension, it can simply be heated to the desired temperature, preferably under boiling conditions. Since the length of time during which such mixtures must be heated in order to achieve the desired result depends on various factors such as pH and temperature, no precise values can be given with regard to the lower and upper limits of this heating time will. However, the time can be determined by previous experiments using relatively simple methods. For this purpose, a sample is subjected to the mixture to be heated to the heat treatment under the desired conditions, and be removed from the reaction mixture .Proben in different periods * These samples are then filtered, dried with V.'asserstoff at 4-50 ⁰ C. 'according to conventional methods using a hydrogen flow of JO l / h. Reduced per 0.5 g composition. The catalysts thus obtained

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v / earth characterized in that their nickel consumption and their selectivity is determined in the catfish described above.

These parameters are then taken as a measure of the period of time during which the mixture must be subjected to the heat treatment. The lower limit of this period of time is that at which a composition is obtained which gives a catalyst with a nickel consumption of less than 0.10 g / 100 g of standard whale oil. Although even prolonged heating does not affect this parameter much, such heating ultimately has an adverse effect on selectivity. For this reason, the upper limit of the heating time should be such that the dilatation at 30 ^° C. (D ^ ₀ ) is still below 100.

To explain it, it should be noted that very good Results are obtained when using a suspension of freshly precipitated nickel hydroxide and support material in aqueous Alkali hydroxide with a pH of 12 to 13 during a ' Boils for 5 to 10 minutes.

. It should be noted that boiling a suspension of containing freshly prepared nickel hydroxide and silicon dioxide Material in aqueous alkali as obtained in the first phase of the process and which has a pH value from 7 to 10.5 does not have a composition with the produced desired properties, which illustrates that an adjustment of the pH value to 11 to 13.5 is essential is.

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An alternative way of working is that the mixture having a pH of from 11 to I, j>, 5d3r V / _r ärmebehand- as lung is subjected follows. First, most of the aqueous solution is removed from the mixture, e.g. by filtration or centrifugation. The resulting paste is then dried by customary methods, even at 50 to 120 ^° C., until weight loss is no longer observed. Usually the resulting composition gives a catalyst with the. Required properties, but · this should also be checked in preliminary tests, because under the given conditions, eg ■ when the paste in a very thin. Layer is dried - the drying time is too short to allow sufficient mutual interaction between the components. This must be avoided because once the composition has been freed of water, even repeated heat treatment does not improve the quality of the composition sufficiently. Since the effect of the heat treatment depends not only on the contact time, but also on the pH value of the aqueous alkali hydroxide, it is useful in cases where short drying times are expected, e.g. when the mixture If it is dried in small quantities or in a thin layer, the pH value of the external alkali metal is increased to a value of at least 12. - _;

Regardless of the method used to heat the mixture, the solid composition is preferably as far as possible from foreign ions, which are obtained from the nickel salt starch used as the starting material, by washing with water or _; freed with aqueous alkali hydroxide before. it is dried. If nickel sulfate as the starting material

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is used, this washing stage is even essential. If the heat treatment in the boiling of a suspension ναι Nickel hydroxide and carrier material, this can Washing stage either before or immediately after the heat treatment are executed. If the heat treatment consists in drying a thick paste, it must be washed before it is placed in the drying oven. · · ■.

After the heat treatment is finished, the resulting composition, obtained either by drying a paste or by boiling a suspension followed by filtering the contaminants and drying the solids, is activated by reacting it with hydrogen by conventional methods, preferably reduced at a temperature between 400 and 550 ° Cy in order to obtain the desired nickel-on-silica catalyst. A very suitable activation method is that the composition is incorporated in a. Hydrogen atmosphere at a temperature of about ^ 50 ⁰ C about JO min heated.

Although the various steps in the process noted above can be carried out in batches, there are some of modifications particularly suitable in continuous Way to be carried out.

In a particularly preferred embodiment of the These modifications are made to the method according to the invention combined in a continuous process as follows. An aqueous solution of a nickel salt and an aqueous solution

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Suspension of the silicon dioxide containing material, either separated or combined, and an aqueous solution of alkali hydroxide are added simultaneously to a first vessel introduced, which is equipped with a heating system, an effective stirrer, a pH value electrode coupled to a pH meter and an outlet which usually consists of an overflow ..

During the addition, the reactants are thoroughly mixed while the mixture formed is maintained at the desired temperature ψ, which is preferably maintained at 'a constant value by coupling of the heating system with a temperature control device. Furthermore, the concentrations of the reactants and their relative amounts added are chosen so that the pH of the mixture formed is kept at the desired value.

This is preferably done by regulating the additional amount one of the constituents, usually the aqueous alkali hydroxide, ζ.B. by means of a solenoid valve, which is activated by the pH meter, which records the pH value of the mixture, is operated. This valve can directly control the flow of the aqueous alkali metal or it can regulate the. River one regulate additional stream of alkali hydroxide, which is superimposed on the main stream. , ■ ·

Finally, the dimensions of the vessel are chosen so that that the mean residence time of the mixed reactants is between about 3 and 10 minutes, preferably between and .7 min. The resulting suspension may do that Vessel leaves through the outlet, then becomes a second one

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Vessel introduced, which also comes with a heating system, a effective stirrer, a pH value electrode and an outlet is provided. Simultaneously with this suspension, an aqueous solution of alkali hydroxide is introduced into this vessel, the solution being of a concentration high enough to bring the pH of the resulting mixture to the required level To adjust the height. The ingredients are thorough mixed throughout the process, while the temperature of the mixture and its pH in the same way as as described above. In this case the pH is kept at the desired value by regulating the amount of the aqueous alkali hydroxide added. The dimensions of this second vessel are chosen so that the mean residence time is within the limits, polygamy determined by preliminary tests as described above, is usually between 5 and 15 minutes. The second The suspension leaving the vessel is then collected and used as above described, worked up.

With respect to those to be used as raw materials Materials, the following should be noted. Although either Nickel salt, which is soluble in water, can be used can, is preferred - especially for manufacturing in applied on a large scale - nickel sulfate as this is the cheapest technically available nickel salt.

The choice of silicon dioxide containing material is made again on a large scale, determined by economic factors, and it has been found that-excellent results by using kieselguhr, which is a relatively cheap product.

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The same situation is with regard to the number of in any one of the steps of the process used, and in general SFatriuinhydrojxyd, which is an cheapest is used.

The invention will in the next before Nun Examples 3, ^ »Dt 6-j 7 ^ur -d 9 illustrates, while Examples 1, 2, 8, 10 and 11 are added to Vergleichszweeken.

In all of these examples the same basic layout was used as in the drawing -schematise]! shown is, this system consists of:

(a) three feed vessels 1, 2 and>., which via lines 4, 5 and β and pumps I ₃ 3 and 9 with:

(b) a reaction vessel 10 connected to the

(1) a v / irksairien Hührer 11,

(2) a contact thermometer 12, which has a first Relay 13 of a heating coil l4 regulates,

(3) a set of pH electrodes Ip, which control a magnetic 3 - \ - ieg & -valve Io via a pH meter 16 and a second heater I7,. which is connected to one of the lines 5 and connected to the supply vessel 2 via a second line 5 ', and

(4) an overflow I9, either to the filter or to a second furnished in the same way Reaction vessel leads,

Is provided.

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example 1

A preparation of a mixed suspension of nickel hydroxide and diatomaceous earth mixed with sodium hydroxide with a pH of 9.0-0.2.

The feed vessels are loaded as follows: Gefä.3 1 with a suspension of diatomite (14 g / l) in a

aqueous solution of nickel sulfate (Ο, δρη), Vessel 2 with an aqueous solution of sodium hydroxide

(0.5η; pH 13.4),
Vessel 3 with an aqueous solution of sodium hydroxide (0.65N; pH 13.6) -

The reaction was started by simultaneously pumping in the pebbles and the external 0.85N sodium hydroxide solution in approximately equal amounts into the reaction vessel, while the suspension formed was being vigorously stirred. This suspension is heated by the heating coil and kept at a constant temperature of 90 - 2 ° C r.si. The pH of the suspension is set to a constant v: ert 9.0 to 0.2 (measured at 20 ⁰ C) regelr.ä3ire dosage of the aqueous O, 5N Natriumhydroxydiösung eir.-estellt. The total amount of liquids added was such that after a steady state had been achieved in the vessel, the suspension had an average dilution of ex; wa 7 nin. That part of the suspension which left the vessel through the overflow before the constant level was reached was discarded.

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B Working up the suspension * ■

The suspension obtained, as described above, was filtered off, the filter being replaced every half hour. The precipitate was washed with water until fine sulfate ions were more present in the washing liquid, after which the resulting wet product was ^{dried at 120 °} C. for 16 hours.

C The composition obtained, as it is described under B, was activated by known methods, in that it was -30 min · at 450 ° C. with a stream of hydrogen with a flow rate of J> Q l / h. treated per 0.5 g of composition.

The properties of the nickel-on-silicon thus obtained dioxide catalyst are given in the table below. ■ "■■ -'- ■ '· ■,

Example 2

The mixed suspension of nickel hydroxide and diatomaceous earth prepared as described in Part A of Example 1 was collected and boiled for 60 minutes.

The precipitate was φίϋ ^ ΐβ ^ and with water. washing, until the washings were free of sulfate ions, after which the wet product 1'6 hrs. at 120 ⁰ C was dried. The resulting composition was activated as described in Part C of Example 1 to give a nickel-on-silica catalyst, the properties of which are also shown in the table below. '

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Example. 35

The mixed suspension of nickel hydroxide and diatomaceous earth, prepared as described in Part A of Example 1, was collected, filtered and washed with an aqueous 0.1 N sodium hydroxide solution (pH 12.0) until no sulfate ions were present in the Washer fluid showed more. The moist filter cake (in which the adhering aqueous solution had a pH of 12.0) was then ^{dried for 16 hours at 120 °} C., after which the resulting composition was activated as described in Part C of Example 1 has been. A nickel-on-silica catalyst resulted, the properties of which are given in the table below.

Example k-

The mixed suspension of nickel hydroxide and diatomaceous earth prepared as described in Part A of Example 1 was collected and filtered. The solids were washed with an aqueous 0.1 N sodium hydroxide solution (pH 13.0) until the washing liquid was free of sulfate ions. The wet composition (pH of the adhering liquid 13.0) was ^{dried for 16 hours at 120 °} C. and, as described in part C of example 1, activated. The result was a nickel-on-silica catalyst, the properties of which are given in the table below.

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Example 5

The mixed suspension of nickel hydroxide and diatomaceous earth, which had been prepared as in Part A of Example 1, was continuously transferred into a second reaction vessel equipped in the same way. In this vessel, the temperature of the suspension was kept constant at 90-2 G, while the pH value was kept at a constant value of 13-0> 3 (measured at 20 ° C.) in a position that was completely identical to that in the first C-efäS was the same. but now by means of a regular dosage of an aqueous 2N w sodium hydroxide solution, it was settled. The dimensions of this ^v: second Reaktionsgefä3es were such that. after reaching a constant state, the mean residence time of the suspension in this vessel was about 5 minutes.

After leaving the second vessel through the overflow the suspension was collected and filtered off.

3 The wet filter cake, which had been obtained as in Part A of this example, was washed with a fleece until there were no more sulfate ions in the washing liquid. Demand .. drying the resulting wet composition during) Ιό hrs. At 120 ⁰ C., it was "activated as in part C of Example 1 '. There was a IJickel-'on-Silieiurfldioxyd catalyst, whose properties in the table are specified.. '·. ■■ "-

Beisoiei ο

The wet filter cake, which had been prepared as in Part A of Example 5, was washed with a 0.05N sodium hydroxide solution (pH value 12.7) until the

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V. 'ash liquid was free of sulfate ions. Has been After drying the resulting Zusaraineneetzung for 16 hours at 120 ⁰ C it was enabled This, in part C of Example 1. A nickel-on-silicon dioxide catalyst resulted, the properties of which are given in the table below.

Example 7 "

The mixed suspension of kickel hydroxide and kieselguhr, prepared as in Part A of Example 1 was collected and filtered. The wet pests as much as possible without being washed first freed from adhering moisture by tightening them. pressed on the filter, but without drying it. That I The resulting product was then dissolved in about 10 times its volume of aqueous O, lN sodium hydroxide solution (pH 13.0), before this suspension is boiled for 30 min became. Of the !.' leather shock was filtered off and washed with water, until the washing barrel was free of sulfate, after which he Drying at 120 ° C for 16 hours. The resulting product was activated as described in Part C of Example 1. This resulted in a nickel-on-silicon oxide catalyst whose properties are given in the table below.

Example p

A The feed bins were loaded as follows:

Geiä3'l rr.tz a suspension of diatomaceous earth (14 g / l) in

distilled. ..assers ^

Vessel 2 with an aqueous solution of sodium hydroxide (0.85N; pH-. '. * ert 13 * 6 ^ and

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■ .. ■■; ■■. . - 20 - ■ '.,. . ■■ _.- ■■■ .. ■ '■■! ■; ■ - ■. · ..

Vessel 3 rait an aqueous solution of nickel sulfate (0.85η).

The reaction was started by simultaneously pumping the three components into the reaction vessel, the volumes of kieselguhr suspension and nickel sulfate solution - 'per minute which were introduced into the vessel being equal, and the amount of aqueous sodium hydroxide being regulated in this way that the pH value within the suspension formed is kept at a constant level of 9.0-2 (measured at 20 ^° C.) during the reaction. The total amount of liquid was such that, after a steady state had been reached, the mean residence time of the suspension in the vessel was about 6 minutes C. That part of the suspension which left the vessel through the overflow before 'the stagnant state was reached was discarded.'

B The suspension, which had been obtained as described in part A of this example, was filtered off and the solid ·? Fabrics were washed with water until the wash water was free of sulfate. The composition thus obtained was dried for 16 h »■ at 120 ⁰ C, after which it, as besehrieben in Part C of Example 1 \ activated. A nickel-on-

Siiiciumdioxyd catalyst whose properties are given in the "demand" table.

^::. The mixed suspension of nickel hydroxide and diatomaceous earth, prepared as described in Example 8, Part A, was filtered off and the solids became

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ORIGINAL INSPECTED

washed with an aqueous 0.05N sodium hydroxide solution until the washing liquid was free of sulfate.

.. After drying the wet product (pH of the aqueous solution adhering to 12.7) for 16 hrs at 120 ⁰ Q was this, as described in Part C of Example 1, ^{aktiviert.Ss:} resulted in a nickel-on- Silica catalyst, the properties of which are described in the table below.

Example .10

A The feed vessels were loaded as follows:

Vessel 1 x with an aqueous solution of nickel sulfate (0.85N);

Vessel 2 with an aqueous solution of sodium sulfate. (0.5n; pH 13.4), and

Vessel 3 with a suspension of diatomaceous earth (14 g / l) in one aqueous solution of sodium hydroxide (0.85N; pH 13.0).

The reaction was started by adding the nickel sulphate solution and the alkaline solution into the reaction vessel at the same time Kieselguhr suspension were pumped, with approximately the same additional amount were used while die.sich resulting suspension was stirred vigorously.

V / hile the reaction, the suspension to a temperature of 9o - held for 2 ° C while its pH to .einem constant value of 9.5 - 0,1 (measured at 20 ⁰ C) through a

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- 22 - ■ ■ '.

regular dosing of aqueous 0.5N / -NatriuTihydr oxy αϊ solution was kept. The additional amount or speed of the combined components was such that after reaching, one more constant! State the. mean residence time of the Suspension in the reaction vessel was about 6 min. The one Part of the suspension, which the vessel through the overflow. left before a steady state within the Reached was discarded.

The mixed suspension of nickel hydroxide and silica, obtained as described in Part A of this example, was filtered off and the contaminants were washed with water until the ash water was free of sulfate. ^Fter drying the resulting product for 16 hrs. At 120 ⁰ C it was activated, as shown. this has been described in Part C of Example 1: A nickel-on-silica catalyst resulted, the shafts of which are shown in the table below.

Example 11

The mixed suspension of nickel hydroxide and diatomaceous earth, which had been prepared as described in Part A of Example 10 - was filtered off and the solids were added aqueous 0.05N sodium hydroxide solution (pH 12.7) gev / ash, until the liquors were free of sulfate.

The wet product (pli-l / ert of the adhering aqueous solution 12.7) was 16 hours. dried at 120 ⁰ C and the dried

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Product was activated as in Part C of Example 1 has been described. A nickel-on-silica catalyst resulted the properties of which are given in the table below.

Tabel

Properties of Mickel-on-Silica

Catalysts

example

No.

Nickel consumption, selectivity VJalöl at 180 ° CD _Q (J .Z.)

. 1 0.18

2 .0.18

3. . ' 0.09

4 0.09

5 0.08

6 0.07

S 0.18

9. 'o, o8

0.13

125 (90) 140 (39) 80 (90) 75 (90) 75 (90) 55 (90) AO (90) 100 (9D 80 (90) XOO (90) 100 (90)

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Claims (3)

- 24 - ■■; ■ _ · "claims 1. Process for the production of a nickel-on-silica catalyst, which is suitable for the hydrogenation of fats, including precipitating nickel in the form of nickel hydroxide ur.d / or carbonate from an aqueous solution of a nickel salt by means of an aqueous alkali hydroxide or alkali carbonate, Mixing of the precipitate during or after the precipitation reaction with a support material containing silicon dioxide, k drying the mixture, and optionally activating the mixture by heating in a stream of hydrogen, characterized in that the nickel is precipitated in the form of nickel hydroxide from an aqueous solution of a nickel salt by means of aqueous alkali hydroxide, v, ^r above the pH of the reaction medium during the Precipitation to 7 to 10.5 * measured at 20 ⁰ C, is held "and the mixture, which was obtained by mixing the nickel hydroxide and the silicon dioxide-containing support material before drying at a temperature of 50 to 120 ⁰ C in the presence of an aqueous Medium treated with a pH of 11 to 13.5 in order to give a composition which, after reduction with hydrogen for 50 minutes at 450 ^° C. and with a hydrogen flow of 1K) l / hour, depending ^! 0.5 g of composition results in a catalytic material which has a kickel consumption of less than 0.10 g and a selectivity of "D, _A <100. . 30 ■ ■. - 2. The method according to claim 1, characterized in that the. pH - '/ vert of the medium in which the nickel is lhydroxyd like, during the precipitation of 8 to 10, measured at 20 ⁰ C, is maintained. - BATHROOM LOCAL 0098 107 1536 - 3. Process according to Claim 1 or 2, characterized in that the pH value of the reaction medium during the precipitation is kept at a constant level, being the maximum The deviation i amounts to 0.2 pH units. * τ. Process according to one of Claims 1 to 3, characterized in that the temperature of the reaction medium is kept at 90 to 100 ^° C during the precipitation. 5. The method according to any one of claims 1 to ^ i-, characterized characterized that the nickel hydroxide with the silicon dioxide containing carrier material is mixed during the precipitation reaction, the formation of a suspension of the carrier material in the aqueous alkali hydroxide prevented is before the aqueous Alkällhydroxyd with the aqueous Solution of the nickel salt is combined. 6. The method according to any one of claims 1 to 5, characterized in that a suspension of the mixture of nickel hydroxide and Siliciumdloxyd.halteendem carrier material in an aqueous medium with a pH of 12 to IJ> and the suspension then at boiling point 5 to Is heated for 10 min. 7 ". Method according to one of claims 1 to 6, characterized in that p-.ekennzelehnet that it is carried out as a continuous process is by adding an.aqueous solution of a nickel salt and an aqueous suspension of a Slliciumdiöxyd-containing material, either separately or combined, and 0098 10/1536 an aqueous solution of an alkali metal hydroxide in a first reaction vessel in such a vessel. The extent to which the pH value of the reaction mixture is between 7 and 10 ·>5> measured at 20 ° C, the temperature being kept above 90 ° C during the reaction time, and the participants having a residence time between J5 and 10 minutes in the vessel, in order to deliver a sludge of freshly precipitated nickel hydroxide and silicon dioxide containing material, this sludge is transferred to a second vessel 3, in which it remains between 5 and 15 minutes and in which it is with a further Alkälihydroxydlösung mixed v / irä, in order to bring the pH value of the contents of the second vessel in the range of 1.1 to 13 * 5j measured at 20 ⁰ C, and in which the temperature is kept between 50 and 120 ⁰ C to give a "composition" which on reduction with hydrogen "., substance during JX) min at ^ 50 ⁰ G and with a hydrogen flow of JO l / h. 0.5 S composition comprises a catalytic material results in having a nickel! consumption of less than 0.10 g and a selectivity of D _ ^ _ <making 100. 3. Nickel-on-SiliciumdioJord- ^ atalysator, which is suitable for the hydrogenation of fats, characterized in that it has a nickel consumption of less than 0.10 g and a selectivity of D ^ _Q <100. 009810/1536 BAD ORIG.NAW