DE2150975B2 - Nickel-silica catalyst and its uses - Google Patents

Description

The invention relates to a nickel-silicon dioxide catalyst with a nickel content of 25 to 50% by weight, based on the total weight, obtainable by joint precipitation of nickel and silicate ions from aqueous solution on porous silicon dioxide particles with the addition of ammonium bicarbonate or another water-soluble alkaline Precipitant and heating, calcining the precipitated, filtered off and dried solid particles in the presence of an oxygen-containing gas or of air at temperatures of 315 to 480 ⁰ C and activation with hydrogen at 315 to 480 ° C, the porous silicon dioxide particles 10 to 70 wt. % of the total silica, characterized in that an aqueous solution containing 10 to 20 g per liter of silicate ions and slurried porous silica particles, over the course of 5 to 40 minutes at a steady rate with an aqueous solution containing 30 to Contains 45 g of nickel ions zt is before the water-soluble alkaline precipitant is added, and that the catalyst has a specific surface of the nickel of 75 to 10CImVg and a sodium content of 0.1 wt .-% or below, as well as its use for the hydrogenation of organic compounds, in particular benzene or aldehydes from oxo reactions.

The nickel-silica catalyst according to the invention has a stabilized high specific surface area of nickel, is highly active and contains very small amounts of alkali metals. The inventive nickel-silicon dioxide catalyst shows in the Hydrogenation of organic compounds compared to catalysts with lower specific surface areas of nickel and relatively elevated concentrations of active catalyst in alkali metals improved activity,

Nickel-SUicjumdiojLid catalysts on carriers porous silica particles, such as diatomaceous earth, infusion earth, Diatomaceous earth, or silica containing earth, are known and have been used to a great extent for Hydrogenation reactions found application. Typical

ίο hydrogenation reactions are z. B. the hydrogenation of Olefins to saturated hydrocarbons, the hydrogenation of aromatics such as benzene, and the Conversion of oxoaldehydes to the corresponding alcohols. Until now, however, it has been because of the

is limited activity of the known nickel catalysts and the fact that these catalysts deactivate fairly quickly is not entirely satisfactory Processes developed for these hydrogenation reactions

Investigations have shown that the activity of the catalysts in dtreklem connection with the specific surface area of the nickel and the catalysts are deactivated more quickly if the specific surface of the nickel is reduced. That means catalysts with a high specific surface area of nickel have a higher activity and a longer catalyst life.

In US-PS 33 51 566 a nickel-silicon dioxide catalyst is described, the specific surface of the nickel is much larger than that of the known Catalysts. Specific surface areas of between 45 and 60 mVg are specified. The specific Surface area of nickel is expressed as the area per unit weight of nickel or per unit weight of the whole

} 5 catalyst (mVg) expressed. All are present specific surface areas of nickel on the basis of area per unit weight of the total catalyst specified.

In accordance with the invention, surprisingly, it was solid provided that one using carefully controlled critical conditions in the preparation of the Catalyst can produce a supported nickel catalyst on porous solid particles, which has a specific Surface of the nickel of 75-10OmVg and has a catalytic hydrogenation activity that is several Times larger than that of the known nickel catalysts.

With the aid of the nickel-silicon dioxide catalyst according to the invention with a specific surface of the nickel of 75 to 100 mVg of the active catalyst and an alkali metal content of 0.1% by weight or below is the hydrogenation of organic compounds with multiple chemical bonds in general significantly improved.

In a preferred embodiment, the nickel-silicon dioxide catalyst according to the invention has overall a specific surface area of about 225 to about 30OmVg, based on the total weight of the active catalyst.

μ The production of the catalyst according to the invention requires the use of separate aqueous solutions. In a first solution 10 to 20 g per liter Silicate anions, dissolved in a second solution per liter of 30 to 45 g of nickel cations. In which the silicate anions

^hr> solution containing a porous silica such as kieselguhr slurried. The two solutions are made by adding the nickel-containing solution to the silicate solution within 5 to 40

Minutes mixed. By this mixing of the two readings previously made, the amount of dissolved nickel in the reaction mixture is kept extremely low, generally well below 0.60 mol / l of the aqueous mixture Nickel essential. The addition should also take place at an essentially constant rate with vigorous mixing so that a catalyst which is as uniform as possible is formed. The mixture is then heated to its boiling point and a precipitant is added to precipitate the dissolved silicate and nickel ions on the porous support. A preferred precipitant is NH ₄ HCO ₃ . Alkali metal carbonates, hydroxides and oxides are generally not desirable precipitants for this process because of the likelihood that some alkali metal will ultimately be incorporated into the finished catalyst.

Water is added during production, to continuously replace water lost through evaporation and thus an almost constant one Maintain volume. The aqueous mixture is kept at its boiling point for 1-5 hours, then filtered and the product obtained washed repeatedly with boiling water. Then the catalyst dried, calcined in oxygen and activated. The activation process consists of the Bringing catalyst into contact with a stream of hydrogen

As already stated, the solution containing nickel ions and the solution containing silicate ions are used Solution mixed under dilution conditions, see above that the amount of dissolved nickel ions in the resulting aqueous mixture is extremely small held and thereby a catalyst with a high specific surface area of nickel is obtained. In addition, it is essential in the preparation of the catalyst according to the invention that the precipitation of the Catalyst takes place from dilute solutions, d. h "the Solution containing nickel ions must have a nickel ion concentration of 30 to 45 g / l and the silicate ions containing solution must have a silicate concentration of 10 to 20 g / l. This precipitation is different differs from the precipitation of a more concentrated solution in which the solution contains up to twice as much solute contains.

Contains 30-90% by weight of the total silica of the activated catalyst come from the precipitated silicate ions. Preferably, however, come 50-70% by weight of the total silica content of the silicate ions. The molar ratio used Nickel: silicate is then typically 0.75: 1 up to 1.75: 1.

The usual steps in the preparation and activation of the catalyst are the same as above described identical. The use of the dilute solution results in a catalyst with essentially the same specific surface area of nickel, but a considerably higher catalyst activity. In fact, e.g. B. in the hydrogenation of benzene, the activity is increased by a factor of about 2.

Although the processes in the preparation of the catalyst according to the invention are not based on a specific one Theory, it is assumed that the use of the additional solvent, d. H. of water, the concentration of alkali metal ions in the solution decreases, making less Alkali metal, for example sodium, can be introduced into the precipitated crystallites. Definitely haunted Research has shown that repeated washing of the nickel-silica catalysts the alkali metal content these catalysts do not decrease and thereby their activity increases only if in the above In the manner described, dilute solutions are used, one obtains highly active catalysts which have little

Contain sodium.

The catalyst of the invention is used in particular as a hydrogenation catalyst Hydrogenation of aromatics, e.g. B. for the hydrogenation of Benzene to cyclohexane, for the hydrogenation of saturated

Is and unsaturated aldehydes to alcohols, as in the known oxo process, for hydrogenating the double bonds in edible fats and oils and other straight-chain and branched olefins and for hydrogenating nitro compounds to amines are used. The term "olefins" means unsaturated compounds with at least one multiple bond and includes multiple unsaturated compounds.
To produce the catalyst, the nickel and silicate ions have to be precipitated together on a porous, solid, particulate silicon dioxide support. First the two solutions are prepared, one of which is a source of silicate ions, such as alkali silicates, i.e. sodium and potassium silicates,

Jo sodium metasilicate silicic acid or hydrolyzed Silicone hydride, in an amount of 10 to 20 g Contains silicate anions per liter and at normal pressure

and room temperature can be maintained.

The second solution contains a source of nickel catalyst

ions, e.g. B. nickel nitrate, nickel chloride or nickel bromide, in a nickel concentration of 30-45 g / l.

Other known sources of nickel cations and silicate anions can also be used.
The porous solid silicon dioxide particles are suspended in the solution containing the silicate anions. Particularly suitable porous particles are kieselguhr, infusion earth, diatomaceous earth, earth containing silica or silicon dioxide. The concentration of the porous solid particles can be expressed as a percentage of the total silica in the catalyst and must be 10-70, preferably 30-50% by weight.

The two solutions are given to each other at low speed, to a maximum

W to create a mixing effect. Typically, a Nickel nitrate solution evenly within 5-40 minutes, preferably 10-30 minutes, to one Given sodium metasilicate solution. After mixing the two solutions, the common Precipitation of the nickel and silicate ions by adding a water-soluble, alkaline precipitants such as ammonium bicarbonate are completed. the Solution should then be heated to around its boiling point. Alkaline ammonium precipitants are for that

w reduction in the amount of alkali metal residues, which are removed from the finished catalyst by washing to avoid poisoning must, most suitable. In some cases, potassium precipitants can be used if the potassium is

h5 acts as an accelerator, not as a poisoning agent.

The metal salts are preferably the water-soluble compounds, e.g. B. the nitrates, or formates Oxalates used. The preferred catalytic metal

is Nicke), but other catalytic Metals are used. These metals include cobalt and iron.

After the precipitation, the mixture is kept at the boiling point for about 1 -5 hours. It is then filtered and washed four times with boiling water. The precipitated catalyst is then dried by being about l-5stündiges heating to 90-205 ⁰ C thereon by 2-8stündiges, preferably 3-5stündiges heating in the presence of an oxygen-containing gas or air to a temperature 315-480 ° Ccalciniert

When the calcination is complete, the catalyst must be reduced to activate. The reduction is carried out in the presence of hydrogen. The hydrogen is passed over the catalyst at room temperature at a rate of 51 / h / g catalyst to 10 l / stcL / g catalyst, preferably from 10 l / h / g catalyst to 30 l / h / g catalyst Then the temperature increases at a rate of about 5.5 ⁰ CZMm. increased to 315-480 ⁰ C This temperature i _; nd the flow of hydrogen is maintained for about 1-4 hours, preferably more than 2 hours.

The reduction is carried out either batchwise or continuously, preferably after the catalyst has been placed in a suitable reactor. Reactors for this purpose are known

At this point the catalyst is sensitive to deactivation and cannot be stored at ordinary temperatures in the presence of oxygen without prior passivation. Passivation can consist in flushing the reactor ^{with an inert gas, preferably nitrogen, at a temperature of over 150 °} C., cooling it to room temperature and then passing the inert gas over the catalyst, air in such an amount into the inert gas introduces that about 1-2 mol% oxygen is present. This process gives Her catalyst a surface coating of oxide and is passivated

In the reduced state, the catalyst obtained has a specific surface area of the nickel of 75-100 mVg and a total specific surface area of 150-30OmVg. The catalyst also contains 0.1 wt% or less netrium and 25 to about 50 wt% nickel. This catalyst is extremely effective in the hydrogenation of olefins (this term includes diolefins and similar compounds), aromatics, saturated and unsaturated aldehydes, in the oxo process, in the hydrogenation of edible fats and oils. Nitro compounds to amines, preferably in the hydrogenation of straight-chain and branched Cj-C »-Oiefins, Q-Cjo-aromatics, including condensed non-aromatics and C ₁ -C20 aldehydes.

The catalyst of the invention is particularly useful in the hydrogenation of benzene to Cyclohexane. In the presence of this nickel-silica catalyst containing 0.1% by weight or less of sodium in the active catalyst obtained significantly improved results.

The conditions when using the catalyst according to the invention in the hydrogenation reactions indicated vary widely and are known. In general, the following conditions may wsrden applied: temperature 65-54O ⁰ C; Pressure 1 atmosphere to 840 atmospheres gauge; Feed rate 0.2-100 parts by volume / hour volume; Hydrogen supply 355-1780 mVm ³ ,

In the Oxo process, carbon monoxide and Hydrogen added to alkenes to make alcohols, aldehydes and other organic compounds with To obtain oxygen functions. Typical alkenes found in Those with 2-20 carbon atoms can be used in this process. Conditions for the oxo reaction are temperatures of 65-175 ° C,

ίο hydrogen to hydrocarbon molar ratios of 04 -10.0 and pressures from 7.0 - 70 atm.

The product of such a carbonylation reaction generally consists of aldehydes, acetals and unsaturated, oxygen-containing compounds which require a hydrogenation treatment in a second or further hydrogenation stage. The catalyst of the invention is particularly suitable for use in hydrogenating the aldehyde product
The hydrogenation conditions in this further stage correspond to the conditions generally used in the first stage.

The following examples illustrate the invention. In all examples the specific nickel surface area was of the catalyst by chemisorption of hydrogen on the reduced catalyst surface at room temperature in a conventional gas adsorption vacuum system measured. This method is extensively described by Yates, Taylor, and Sinfelt in J. Am. Chem. Soc. Vol. 86, pp. 2996 (1964).

example 1
(Comparative example)

A Manufacture of the catalyst

J5 In this example, a catalyst was used with a specific nickel surface of 90 mVg and a content of 0.2 wt .-% sodium

The catalyst was prepared as follows: 1125 g Ni (NOj) ₂ · 6 H ₂ O were added to 2.25 l of water.

then 380 g of Na ₂ SiO ₃ .9 H ₂ O to 2.25 l of water. 50 g of kieselguhr were added to the second solution, stirring well to maintain a suspension. The salts were added to the water at room temperature and stirred until dissolved. An electric stirrer was used to stir at a speed of 600 rpm. The addition was carried out in a standard laboratory device. The nickel solution was then added evenly to the sodium silicate solution over about 15 minutes.

so During this time the sodium silicate solution was vigorously stirred. The mixture was then heated to its boiling point. At the boiling point of the mixture, 800 g of NH4HCO3 were added uniformly within about 15 minutes. During this operation, water was lost through evaporation. Water was added to replace the lost water. After all of the NH4HCO3 had been added, the mixture was stirred at its boiling point for 3 hours. The water lost through evaporation was replaced again. It was then filtered and the solid portion was washed five times with boiling water. Each wash solution consisted of 2 liters of water. Finally, the catalyst feslc at 93 ⁰ C was dried, calcined for 4 hours in air at 400 "C and

fr '· by treatment for several hours with a stream of hydrogen activated at about 354 ° C. About 395 grams of catalyst were recovered.

The catalyst obtained had a specific one

'• Jiekelobcifliii He

¹ JiIlIlHlIl

40 m '/ p and cniliielt 0.? < !

M Use of the katahsatoi

Line! 'Praises · dt ·· - under A hfigistcllicn Kat: il \ salnts was in an oniinuicrlich working lluliic ningMCiiklor / in I hiiw anctltin ^ r win llen / ol in Culnlievnn uses the reading condition c η wading: 'tempera-Mir KH) C; Kaumgcschwinclipkcii 25 (icwii htteilc / Hour / iiewielilsieile: pressure I atmosphere; water substance to hydrocarbon ratio 40 below Hi.n'l'u des llen / ols in ("yclohcxan umgi converts. The conversion was determined by gas chromatography.

H cis ρ ic I 2
(Comparison example)

A Manufacture of the catalyst

Approximately 750 g Ni (NO ₁ ), h HO and 320 ρ Na2.Si () i 9 II; O were added together to 50 g of kieselguhr, which was dissolved in 3.5 l of water. The solution was mixed to reach its boiling point / t and then coated with 800p ammonium carbonate / i. After the dissolution has ended, the dissolution is heated to boiling for a further J hours. The resulting slurry was then lilled. washed, dried and calcined as described in Example I. About 270 g of katal> satoi were obtained. The obtained katal> sat <u hold a nit kclobciflächcnhc rich \ on 47 m '/ g. This ready h was determined in tlie same way as in Example 1.

This example shows that the use of a single solution instead of the separate solutions of Example I produces a catalyst with a much smaller surface area. ie from 90 pegcn 47 m ⁷ / p results.

B Use of the catalyst

For the hydrogenation of benzene, the same conditions were used as in Example IH, however the catalyst prepared under A above was used instead of the catalyst of Example IA. This means that a catalyst was used in the manufacture of which all of the ingredients are directly converted into one Solution rather than mixing separate solutions as in the procedure of Example IA. the Benzene hydrogenation conditions were the same as in Example IB. The conversion to Cyclohexane was only 18%. as determined by gas chromatography.

This example shows that the catalyst of Example 2A has a lower specific surface area than I ndtic iimgsl.atalx sale t nlspieclietid less w ii ksam w ai .il> - ilei Kalalxsaloi of the example I Λ

example 1
(expressly)

A I Ie ι position ties K alalvsatois

In this example ties are made Kaialysalois with the following deviations as in

in example I Λ:

The total amount used for the bulging solutions water was twice that in Example IA. That is, tlas Nitkelilral as well as that Sodium metasilica were each gel st in 5 l of water.

ι, Is about 395 g of catalyst were obtained.

The catalyst obtained had a specific Nickclohei area of about 90 m '/ g and only complied about 0.1% by weight sodium. That means that further dilution has no all-specific effect

. • π Surface of the active catalyst, but was through Doubling of the amount of the solvent and the sodium content aiii half icdii / ietl.

Il use of the catalyst

Exactly the same conditions as in Example ItI were used for the hydrogenation of benzene, however, instead of ties the Kalah salors of Example IA the catalyst provided above iiiitei A Iu used f) ic conversion In contributed () 2.8%. this shows in an improvement by ilen t'altoi 2 over the Catalyst ties example IA and an improvement around a factor of 4 for the catalyst of the example 2Λ. That is, by further diluting the solutions one can achieve a greater Kaialysaloiaklivitäl.

("Use of the catalyst

Kinc sample of the catalyst prepared under A was pcllctisicit and for the conversion of 2-Älhylhexanal used in the corresponding alcohol. the

The temperature conditions were: temperature 135 "C; space velocity 3.0 parts by weight / parts by weight / hour; pressure 35 aiii: hydrogen to hydrocarbon molar ratio 2.5. After 15 hours% .0% of the aldehyde had been converted into oil, while into

J) an experiment carried out under identical conditions using a commercially available nickel catalyst was only 70.1% of the Aldehyde were reduced.

This shows a significant improvement in the conversion of alcohols to Oxoaldehydcn due to the greater activity of the inventive 'λ catalyst.

Claims (2)

Claims; 1, nickel-silicon dioxide catalyst with a nickel content of 25 to 50% by weight, based on the total weight, obtainable by the joint precipitation of nickel and silicate ions from aqueous solution on porous silicon dioxide particles with the addition of ammonium bicarbonate or another water-soluble alkaline precipitant and Heating, calcining of the precipitated, filtered off and dried solid particles in the presence of an oxygen-containing gas or of air at temperatures of 315 to 480 ⁰ C and activation with hydrogen at 315 to 480 ° C ₁ wherein the porous silicon dioxide particles 10 to 70 wt .-% des total silica, characterized in that an aqueous solution containing 10 to 20 g per liter of silicate ions and slurried porous silica particles, over the course of 5 to 40 minutes at a constant rate with an aqueous solution containing 30 to 45 g of nickel ions per liter contains, is added before the water-soluble alkaline precipitants are added, and that the catalyst has a specific surface of the nickel of 75 to 10Om ² Zg and a sodium content of 0.1 wt .-% or below 2. Use of the nickel-silica catalyst according to claim 1 for the hydrogenation of organic compounds, in particular benzene or aldehydes from oxo reactions.