DE2144727A1 - Process for reactivating platinum and lead containing catalysts - Google Patents

Description

patkntanwAltb

DR. O. DITTMANN K. L. SCHIPP DR. A. ν. FIVE BR DIPL. ING. P. STRBHL

8 MUNICH 8O MARIAHILFPLATZ 8 * 3

DA-4429

Description of the company's patent application

Asahi Kasei Kogyo Kabushiki Kaisha No. 25, 1-chome, Dojimahamadori ,. Kitaku, Osaka, Japan

concerning

Process for reactivating platinum and lead containing Catalysts

Priorities: September 7, 1970, Japan, No. 77782 / I970 October 28, 1970, Japan, No. 94266/1970 April 22, 1971, Japan, No. 25703/1971

The invention relates to a method for reactivating or regenerating a catalyst containing platinum and lead. It specifically relates to a method of reactivating a catalyst comprising platinum and lead or platinum, lead and contains a third component and the activity of which has been reduced by being used in a reaction. At this In the reactivation method, the catalyst is treated with an oxygen-containing gas for a very short period of time and if necessary, halogen supplied to a stable

209812/1549 ^ ² "

2U4727

~ ² ~ received

To ensure that the activity is maintained for a long period of time.

As explained in German Offenlegungsschrift No. 2 005 828 Catalysts containing platinum and lead, or platinum, lead and a third component, have numerous advantages compared to a conventional platinum-alumina catalyst or a similar catalyst. They are economical advantageous catalysts for the production of aromatic compounds, for example benzene, toluene, Xylene, trimethylbenzene and the like, a base material for high octane gasoline, particularly a base material for unleaded gasoline, due to its high liquid yield, aromatic yield, the high octane value achieved, the hydrogen yield and its low rate of activity reduction.

In the past, there has been a great deal of research into a reactivation method for reforming catalysts and various methods have been proposed for industrial use. For example be as a reactivation method for platinum-alumina catalysts or platinum-alumina catalysts containing a third component, currently used extensively for reforming, usually an oxygen reactivation method and a halogen reactivation method applied, the former requires *

209812/1549

2U4727

- received

J '

carbon deposited by using an oxygen-containing gas at a high temperature for a long time Burn duration. Long-term treatment of a catalyst at high temperature promotes sintering of the active ones Species and, as a result, accelerates the rate of long-term deactivation. If the deposited carbon, which is considered to be the cause of short-term deactivation, is to be removed, there occurs a phenomenon that the growth of particles of the active species occurs. It will believed that this phenomenon is the cause of long-term deactivation which is disadvantageous. On the other hand, in cases where the oxygen reactivation method not sufficient, a halogen reactivation method applied. This method relies on the addition of chlorine and the like the active species to effect acidic puncture such as hydrocracking, isomerizing, cyclizing, and the like.

Although these two methods described above are widely used, common ones used industrially lose

gradually

Catalysts / their activity and become unusable. Such a Ineffective catalyst must be subjected to extraction to recover the active ingredient such as platinum, etc. and are again transferred to a catalyst. The manufacturing cost of the catalyst and the The cost of replacing the catalyst in an industrial device is a cause of an increase in the production cost. 209812 / 1B49 -4-

According to the invention, particular attention was paid to the disadvantage the conventional reactivation method of the catalyst. Through extensive research with regard to a reactivation method for platinum and lead containing catalysts, a reactivation method was found by which enables stable, long-term conduct.

The platinum and lead or platinum, lead and a third component containing catalysts that according to the invention Processes are reactivated have the advantage already mentioned that the reduction in activity is very slight is. Even if a conventional oxygen reactivation method or a halogen reactivation method is used, can of course, their catalytic life would be expected to be longer than that of a platinum catalyst which does not contain lead contains. In fact, comparative examples given later show that these catalysts have a longer life. Nevertheless, they lose their activity, albeit to a lesser extent, and can no longer be used. If of course the process is carried out under milder reaction conditions, the reduction in activity is less. The current endeavors are, however, to place ever stricter requirements on the quality of the product, for example a higher aromatic concentration, a higher one Octane value and the like.

- 5 209812/1549

2U4727

The invention now makes a method accessible which meets these requirements and that on the plague position "is based on the fact that the deposited carbon is hot lower Temperature can be burned within a short period of time.

The invention therefore relates to a method for reactivating a catalyst which contains platinum and lead or platinum, lead and a third component and which is used in particular for hydrocarbon conversion. The inventive method is characterized in that a 0.5 to 5 $> oxygen-containing mixed gas through the catalyst for 2 to 5 hours at 300 to 450 ° C, then i for 1 to 3 hours at 450 to 550 ° G is more than 5> Oxygen-containing mixed gas is passed and, if necessary, a gas containing halogen or a halogen compound in an amount of 0.1 to 10 percent by weight, based on the catalyst, is passed through the catalyst or the halogen or the halogen compound in the final stage in the presence of the catalyst conversion carried out is added to the hydrocarbon feed.

An important feature of the method according to the invention is the burning of deposited carbon at a temperature below 450 ° C for a short period in order to avoid this to promote high temperature firing or sintering of the active species. The reason that the treatment is at this low temperature for such a short period

209812/1549

21U727

- D -

can be carried out is likely to be the effectiveness of this catalytic system on the shape of the deposited carbonaceous material and for burning that material. Treatment at 450 to 550 ° C in the final stage is a process that is performed to remove a very small amount of any remaining, deposited carbonaceous material to burn and will be completed within the shortest possible time. Depending on the condition of the catalyst this stage can also be omitted. The treatment at 450 to 550 ° C in the final stage is also advantageous when it is carried out under a pressure of 1 to 20 kg / cm of a gas stream because the burning of carbonaceous material is promoted. However, if the first stage is performed under pressure, it becomes linear The speed of the gas is lower, as a result of which overheated areas easily occur, which is of course disadvantageous.

The supply of halogen or a halogen compound in the method of the present invention can be completed in a short period of time will. It is sufficient if halogen is an oil used as a raw material or a reactivating gas mixture is admixed at the end of the reaction period.

The reason for the quick effect achieved by the addition of halogen lies in the content of lead in addition to platinum in the catalytic system used according to the invention and it is believed that the lead component is effective for

- 7 209 8.12 / 1549

Is binding of halogen.

The essence of the invention is that the oxygen reactivation stage and the chlorine reactivation step more efficiently Way can be carried out by taking the characteristic property of the platinum and lead-containing catalyst is exploited.

The catalysts subjected to the process of the invention are platinum and lead containing catalysts; However, they can contain at least one third component, such as lithium, sodium, potassium, rubidium, cesium, copper, silver, gold, beryllium, magnesium, calcium, strontium, barium, Zinc, cadmium, mercury, yttrium, boron, thallium, titanium, zirconium, germanium, tin, vanadium, tantalum, phosphorus, antimony, Bismuth, chromium, molybdenum, tungsten, manganese, rhenium, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, Thorium, uranium and the like.

The platinum content is 0.01 to 3 percent by weight and the lead content 0.01 to 5 percent by weight, based on the weight of the catalyst. The third component is if necessary, in a proportion of 0.01 to 3 percent by weight added. However, preferred contents are 0.1 to 1.0 percent by weight platinum and 0.05 to 3 percent by weight lead and 0.05 to 1 percent by weight of the third component. In addition to the stated pro & included is the ratio Pb / Pt important. If namely the relationship

209812/1549 ~ ⁸ ""

of Pb / Pt exceeds a predetermined value, Pb exercises a permanent poisoning effect on Pt and the ratio Pb / Pt is therefore 0.1 to 3 (as a weight ratio) limited. It is preferred to use a halogen-containing compound as the platinum component.

Aluminum oxide, silicon dioxide, Silica-alumina and the like are preferred. An oxide, hydroxide or hydrate is suitable as a starting material one of the materials mentioned, which is in the form of a sol, gel, may be in crystal form or granulated form.

When treating the catalyst with an oxygen-containing one Gas is preferred as an initial oxygen concentration of less than 5 #. Preferably this concentration depends on the amount of deposited carbon, the treatment temperature, the Flow rate of the treatment gas, the amount of catalyst, regulated so that the temperature of the catalyst layer is not increased by this. In a very effective embodiment of the method according to the invention, started with an oxygen concentration of 0.5 to 1.0 # at the beginning of the reaction and this concentration gradually increased to 5 #.

The initial reactivation temperature is in the range from 350 to 450 ° C, preferably in the range from 400 to

209812/1549 " ⁹ "

450 ° C. An effective treatment time is up to 5 hours and is in particular in the range of 3 to 5 hours, It is not preferred to be the initial treatment temperature to increase and to lengthen the reaction time, because both factors reduce the rate of long-term activity reduction enlarge.

It is then necessary to bring the oxygen concentration in the later treatment stage with an oxygen-containing gas to a value of more than 5 $. Air can also be used for this. In some cases, pure oxygen can also be used. It is advantageous that a temperature in the range from 450 to 550 ° C., preferably in the range from 500 to 550 ° C., and a treatment time of up to 3 hours is used.

The supply of halogen is used when reactivation with an oxygen-containing gas is difficult or if it is desired to make the reactivation with an oxygen-containing gas more efficient. The temperature and the duration of the halogen supply stage can have the same values as in the treatment stage with an oxygen containing gas. Thus, the supply of halogen during the process of treatment be carried out with an oxygen-containing gas and the halogen can be carried out in the presence or absence of oxygen are present. In another embodiment it is

- 10 209812/1549

- ao -

also possible to use a halogen or a halogen compound in in the dissolved form in the starting material treated with the catalyst before the reaction is terminated. To a To effectively bind halogen or a halogen compound to a catalytic system without loss is preferred Supply of halogen or halogen compound in the later stage of the oxygen treatment following the stage of To carry out treatment with an oxygen-containing gas.

As the halogen or halogen compound, molecular halogen, hydrogen halide or a hydrocarbon compound are used Fluorine, chlorine, bromine or iodine are used. The amount of halogen supplied is preferably in the range of 0.1 to 10 percent by weight halogen, based on the weight of the catalyst » In cases where mild reaction conditions are applied, or in cases where reactivation is carried out at a time when the activity of the catalyst is not so much reduced is also the supply of halogen is not always necessary.

The reaction in which the catalysts reactivated according to the invention Are used is the conversion of hydrocarbons, such as hydrocracking, dehydrogenation, isomerization, dehydrogenative cyclization, dealkylation, reforms and similar hydrocarbon conversions. The hydrocarbons to use consist mainly of hydrocarbons with a boiling point in the range from 40 to 250 ° C. Industrial

209 8.12 / 1549 " ¹¹ "

-11- 2UA727

advantageous raw materials are light gasoline, heavy gasoline, kerosene, gas oil and the like. As reaction conditions can a reaction temperature of 300 to 650 ° C, in particular 430 to 580 ° C, a reaction pressure of 1 to 50 kg / cm, especially 1 to 20 kg / cm, a ratio of hydrogen to hydrocarbons of 0.5 to 15, preferably 2 to 10 and a liquid hourly space velocity of 0.25 to 10 h ~ be applied.

Purely the method according to the invention, it is characteristic that the reactivation is carried out at a lower temperature and for a shorter duration, using the characteristic feature of the catalyst containing platinum and lead is exploited. This achieves advantages that are achieved with other catalysts cannot be reached. The process according to the invention also increases the service life of the catalyst prolonged to such an extent that it has not hitherto been observed when the consequence of reaction and reactivation is repeated. In addition, a high activity can be maintained and therefore aromatics and oils with high Octane value can be obtained at lower cost and in higher yield. Because reactivation at a lower temperature and is carried out for a shorter period of time, reactivation takes place with less effort and reduced costs. The inventive method is technically advantageous because the reactivation is carried out in as short * time as within 8 hours and because the replacement of the catalyst in the reactor is not required.

209812 / 15A9

example 1

Powdered alumina (γ-alumina) having a purity of 99.9% was granulated into grains of 2 ml and then calcined at 650 ° C. for 5 hours to prepare a carrier. The carrier obtained was immersed in an aqueous solution of chloroplatinic acid and lead nitrate, evaporated to dryness and baked at 550 ° C. for 3 hours. A catalyst with the composition (0.5% Pt 0.4 $ Pb) / Al ₂ O * was obtained.

Using the obtained catalyst, a gasoline of the following composition (the same material is also used in the following examples) was reformed as a raw material under the following conditions: reaction temperature 500 ° C, reaction pressure 20 kg / cm, ratio of H ₂ to gasoline of 5.0 and Hourly Space Velocity (LHSV) 4.0 h ~. The total aromatics yields in the initial period of the reaction and after 50 hours were 67.3 # and 51.5 S ^ ·

Further, the average research octane value of the liquid formed was 103 over a 50 hour period.

After the reaction, the catalyst was reactivated using the following method:

Through the catalyst a 0.6% oxygen were successively for 4 hours at 410 ° C containing a nitrogen stream for 2 hours at 520 ° C, a $ 6> oxygen-containing nitrogen stream of a gas space velocity of

-.13 209812/1 549

21U727

1500 h ~, and directed a hydrogen chloride and 6 $> oxygen-containing stream of nitrogen for one hour at 520 ° C. The amount of chlorine fed in at this point was 0.7 percent by weight based on the weight of the catalyst.

Using the catalyst reactivated in this way, reforming was carried out under the same reaction conditions as before reactivation. In the initial period of the reaction, aromatics yields of $ 68.2 and after 50 hours of aromatics yields of $ 50.0 were achieved. Further, the average research octane value of the resultant liquid over 50 hours was 103.

Composition of gasoline used as raw material;

Paraffin 66.3

Naphthene 17.2 ""

Aromatics 16.5 ""

Sulfur 70 parts per

1 million parts (ppm)

Boiling point 89 to 189 ° C

Example 2

The same carrier material as in Example 1 was immersed in an aqueous solution of chloroplatinic acid, lead nitrate and uranyl nitrate dipped, evaporated to dryness and baked at 550 ° C for 3 hours. A catalyst for the

- 14 209812/1549

(0.5% Pt - 0.5 S * Pb - 0.5 '* U) Al ₂ O ₃ .

Using the catalyst prepared in this way, a reforming process was carried out for 100 hours under the following reaction conditions: reaction temperature 500 ° C, reaction

p

on pressure 10 kg / cm, ratio of H ₂ to gasoline or naphtha 5.0 and liquid hourly space velocity (LHSV) 2.0 h ~ ¹ .

After the reaction, the catalyst was reactivated using the following method:

1 56 oxygen-containing gaseous nitrogen and 3 hours at 520 ° C. air were passed through the catalyst in succession at 400 ° C. for 3 hours. After the described reaction and reactivation had been repeated 35 times, air containing 1,1,2-trichloroethane was passed through for 3 hours at 520 ° C. in the final stage of reactivation. The amount of chlorine supplied was $ 1.5 > *

Thereafter, the sequence of reaction and reactivation with oxygen was repeated 35 times and the reactivation by renewed Adding 1,1,2-trichloroethane made. The reactivation effect at this point had the following value:

- 15 -

2 Π 9 8 1? / 1 S i * 9

■ - 15 -. 21U727

Results of the reaction

Catalyst aromatics yield

(Wt .- ^)

Before reactivation (fresh) 69.1

After 10 repetitions of the sequence of reaction and reactivation (oxygen process) 66.5

After 20 repetitions of the sequence of reaction and reactivation (oxygen process) 64.2

After 35 repetitions of the sequence of reaction and reactivation (oxygen process) * 60.3 After reactivation (oxygen

Halogen process) 70.1

After 35 repetitions of the sequence of reaction and reactivation (oxygen process) 61.2 After reactivation (oxygen-halogen process) 69.9

Example 3

The same carrier material as in Example 1 was immersed in an aqueous solution of chloroplatinic acid, lead chloride and potassium chloride, evaporated to dryness and calcined at 550 ° C. for 5 hours. A catalyst with the composition (0.3 ^ Pt - 0.3 io Pb - 0.1% K) / A1 ₂ O was obtained.

- 16 -

20981 2/1 B A 9

-16- 21U727

Using the catalyst thus prepared, reforming was carried out for 70 hours under the following conditions carried out: reaction temperature 510 ° C., reaction pressure 15 kg / cm, ratio of hydrogen to gasoline 7.0 and liquid hourly space velocity (LHSV) 3.0 h ~.

Then, after the reaction, a stream of nitrogen containing 1.0% oxygen was passed successively through the catalyst for 3 hours at 420 ° C. and a stream of nitrogen containing 5.0% oxygen at 520 ° C. for 3 hours. ·

After the specified sequence of reaction and reactivation had been repeated 35 times, gaseous nitrogen containing 1,2-dichloroethane was passed through the catalyst for 2 hours at 520 ° C. in the final stage of the reactivation. The amount of chlorine supplied was 5.0%. The total aromatics yields obtained by using the fresh catalyst (before reactivation), the catalyst after 35 iterations of reaction and reactivation (oxygen process), and the catalyst after reactivation using the chlorine process were 68.7 #, 61.4 # and, respectively 67.7 Ί »·

Example 4

The same carrier material as in Example 1 was in an aqueous solution of chloroplatinic acid, lead nitrate and

- 17 209812/1649

21U727

Dipped cadmium nitrate, evaporated to dryness and calcined at 550 ° C for 5 hours. A catalyst with the composition (0.5 $> Pt - 0.4 $> Pb - 0.1 # Cd) / Al ₂ O _{5 was} obtained. Using the catalyst prepared in this way, the reforming was carried out for 100 hours under the following conditions: reaction temperature 500 ° C., reaction pressure 10 kg / cm, ratio of H ₂ to gasoline or naphtha 7.0 and liquid hourly space velocity (LHSV) 2.0 h ".

After the reaction, a stream of nitrogen containing 2.0 # oxygen was then passed successively through the catalyst for 2 hours at 430 ° C. and air for 3 hours at 510 ° C. Thereafter, for 3 hours, a 1,1,2-trichloroethane containing air stream at 510 ° C was passed through the catalyst, with 0.5 $> Halogen were fed.

The indicated sequence of reaction and reactivation was carried out 70 times. The results of the reaction were as follows achieved:

Catalyst flavor te t.enausbeu

Before reactivating 69.5 After reactivating once 70.5 After 20 reactivations 68.8 After 50 reactivations 71.2 After 70 reactivations 70.0

- 18 -209812 / 1έ

-ie- 2U4727

Example 5

A Y-AlpO ^ carrier in the form of an extrudate with a diameter of 1.5 mm and a length of 6 to 8 mm was immersed in an aqueous solution of chloroplatinic acid and lead nitrate, evaporated to dryness and fired at 580 ° C. for one hour, with a Catalyst of a composition (0.5 # Pt - 0.3% Pb) Al ₂ O _{5 was} prepared. Using 10 ml of the catalyst thus prepared, the sequence of reaction and reactivation

carried out. The reaction continued for 70 hours under fοίο Lowing conditions made: pressure 20 kg / cm, temperature 490 ° C, liquid hourly space velocity (LHSV) 2.0 and the ratio of hydrogen to gasoline 5.0 while reactivating was performed by sequentially entering a 1 # Oxygen-containing nitrogen flow for 3 hours passed through at 450 ° C and air for 2 hours at 520 ° C became. The sequence of reaction and reactivation was repeated 42 times. At the various stages of the procedure the following average yields of total aromatics were achieved:

Catalyst aromatics yield

In the initial period After reactivating once. After 42 reactivations

Example 6

Using 10 ml of the same catalyst as

209812/1649 - 19th

64. 1 62. 3 61. 1

-19- 21U727

in example 4 the sequence of reaction and reactivation was repeated. The reaction was continued for 100 hours at a Temperature of 500 ° C, a pressure of 10 kg / cm, a liquid hourly space velocity (LHSV) of 2.0 and a hydrogen to gasoline ratio of 7.0 while the reactivation was performed by one hour before the end of the reaction, 1,1,2-trichloroethane was added to the petrol supplied as raw material, so that 0.5 percent by weight of chlorine, based on the catalyst, were added. Then was through the catalyst during A stream of nitrogen containing 2.0 percent by volume of oxygen at 430 ° C. for 2 hours and then at 510 ° C. for 3 hours Airflow directed. The results of the reaction before and after reactivation showed the following values:

Catalyst aromatics yield

Before reactivating (fresh) compartment reactivating once after 20 reactivations

Comparative experiment 1

Reforming was carried out under the same conditions as in Example 2 carried out, with the exception that when reactivating the catalyst, the treatment in the initial stage for 5 hours at 500 ° C and the treatment in the later stage was carried out for 5 hours at 580 ° C.

- 20 209812/1849.

69 .5 68 .2 67 .0

The following reaction results were achieved with this catalyst:

Catalyst aromatics yield

Before reactivation (fresh) 69.1

After 10 repetitions of reaction and reactivation (oxygen process) 66.3 After 20 repetitions of reaction and reactivation (oxygen process) 60.8 After 35 repetitions of reaction and reactivation (oxygen process) 56.6 After reactivation (oxygen

Halogen process) 66.4

After 35 repetitions of reaction and reactivation (oxygen process) 51.3 After reactivation (oxygen

Halogen process) 62.5

Comparative experiment 2

The reforming was carried out using the same catalyst and under the same conditions as in Example 4, with the exception that when reactivating the catalyst, the treatment in the first reactivation stage for 2 hours at 500 ° C and the treatment in the later stage during 3 hours at 580 ° C. The following reaction results were achieved:

- 21 209812/1549

Catalyst aromatics yield

Before reactivating 69.5

After reactivating once 70.9

After 20 reactivations - 67.3

After 50 reactivations 63.4

After 70 reactivations 58.2

Comparative experiment 3

i) he same carrier as in Example 1 was in an aqueous Solution of chloroplatinic acid immersed, evaporated to dryness and calcined for one hour at 580 ° C, with a catalyst the composition 0.5 ^ Pt / AlpO was obtained. Using 10 ml of the catalyst thus prepared, the sequence of reaction and reactivation was among the same Chen conditions as in Example 4 repeated. The following reaction results were achieved:

Catalyst aromatics yield

(Wt .- ^)

Before reactivating 58.3

After reactivating once 60.2

After 20 reactivations 53.0

After 50 reactivations 47.5

20981-2 / 1.649

Claims (12)

21U727 claims 1. Process for reactivating a platinum and lead or a catalyst containing platinum, lead and a third component, characterized in that that in a first stage for 2 to 5 hours at 500 to 450 ° C a 0.5 to 5 percent by volume of oxygen Gas and then in a second stage for 1 to 3 hours at 450 to 550 ° C a 5 percent by volume or more oxygen containing gas passes through the catalyst to be reactivated. 2. The method according to claim 1, characterized in that there is also a halogen or a Halogen compound-containing gas passes through the catalyst in such an amount that 0.1 to 10 percent by weight Halogen, based on the catalyst, are fed. 3. The method according to claim 1 or 2, characterized in that one is used for converting Hydrocarbons used catalyst reactivated and the reactivation and conversion of the hydrocarbons performs repeatedly. " 4. The method according to claim 3, characterized in that that the halogen or the halogen compound in the final stage of the hydrocarbon conversion feeds along with the hydrocarbon feed. 20981.2 / 1649 - 23 - -23- 21U727 5. The method according to claim 1 to 4, characterized in that a catalyst is reactivated, the third component of one or more of the elements lithium, sodium, potassium, rubidium, cesium, copper, Silver, gold, beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, mercury, yttrium, boron, thallium, Titanium, zirconium, germanium, tin, vanadium, tantalum, phosphorus, antimony, bismuth, chromium, molybdenum ,. Tungsten, manganese, rhenium, Contains iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, thorium and uranium. 6. The method according to claim 1 to 5, characterized in that a catalyst is reactivated, the 0.01 to 3 weight percent platinum, 0.01 to Contains percent by weight lead and 0.01 to 3 percent by weight of the third component and a weight ratio of Has lead to platinum from 0.1 to 3. 7. The method according to claim 1 to 6, characterized in that a catalyst is reactivated which contains platinum in the form of a halogen compound. 8. The method according to claim 1 to 7, characterized in that one reactivates a catalyst which is based on one of aluminum oxide, silicon dioxide or aluminum oxide-silicon dioxide existing carrier is applied. 209812/1549 - 24 - -24- 21U727 9. The method according to claim 2 to 8 _t thereby ge. indicates that the halogen or halogen compound used is a molecular gaseous halogen, a hydrogen halide or a fluorine, chlorine, bromine or iodine hydrocarbon. 10. The method according to claim 1 to 9, characterized in that a catalyst is reactivated, which is used to reform gasoline, kerosene or gas oil. 11. The method according to claim 1 to 10, characterized in that a catalyst is reactivated, that for one at a temperature of 430 ° to 580 ° C, a pressure of 5 to 15 kg / cm, a molar ratio from hydrogen to feed from 2 to 10 and a liquid hourly space velocity from 0.25 to 10 h "carried out reaction is used 12. The method according to claim 1 to 11, characterized in that the second stage of reactivation is carried out for 1 to 3 hours at 450 to 550 ° C under a pressure of 1 to 20 kg / cm. 209812/1549