DE1242191B - Process for the preparation of catalysts containing alumina and fluorine - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

BOIj

German class: 12 g - 11/64

Number: 1 242 191

File number: B 67459IV a / 12 g

Filing date: May 29, 1962

Open date: June 15, 1967

The invention relates to the production of catalysts made from aluminum oxide, fluorine and consist of a hydrogenating metal and are suitable for the "conversion of hydrocarbons.

Catalysts containing an inorganic oxide, fluorine and a hydrogenating metal are known, for example are catalysts made of platinum, aluminum oxide and bound halogen as catalysts for the reforming of petroleum naphthas is well known. The amount of halogen can be 0.1 to 8 percent by weight but in practice the amount rarely exceeds 1% by weight. These catalysts are suitable also for the isomerization of hydrocarbons at relatively high temperatures, and According to one publication, the catalyst contains aluminum oxide, a platinum group metal, 2.0 to 5.0 weight percent combined fluorine and less than 0.075 weight percent combined chlorine.

The introduction of fluorine into an oxidic catalyst mass is carried out according to the state of the art Technique by treatment with either hydrogen fluoride or fluorine-containing compounds under conditions in which hydrogen fluoride can form. In particular, it is the use of organic fluorine compounds in the presence of hydrogen, i.e. "under reducing conditions known.

"The subject of the invention is a process for the production of aluminum oxide, fluorine and a hydrogenating metal of the VI. Subgroup and VIII. Group containing hydrocarbon conversion catalysts, by halogenation of activated aluminum oxide with halogen-containing organic compounds under anhydrous conditions at elevated temperatures is characterized in that one works under non-reducing conditions at temperatures of 300 to 500 ⁰ C and contact times of 5 minutes to 24 hours with gaseous fluorine compounds which correspond to the following general formula:

Y-X-F

I. γ

wherein X is carbon or sulfur and Y is fluorine or hydrogen, and in that it introduces the fluorine in amounts of 1.2 x 10 ~ ⁴ to 3.4 x 10 ~ ⁴ g / m ² surface in the catalyst.

Process for the production of aluminum oxide
and fluorine-containing catalysts

Applicant:

The British Petroleum Company Limited, London

Representative:

Dr.-Ing. A. ν. Kreisler, Dr.-Ing. K. Schönwald,
Dr.-Ing. Th. Meyer and Dr. JF Fues,
Patent attorneys, Cologne 1, Deichmannhaus

Named as inventor:

John Norman Haresnape,

Anthony George Goble, Sunbury-on-Thames,

Middlesex (UK)

Claimed priority:

Great Britain 7 June 1961 (20 525)

The claimed new method differs from the prior art in this among other things it is essential that fluorine compounds are used under non-reducing conditions, i.e. under conditions in which no hydrogen fluoride is formed. This procedure has for practice considerable advantages because this eliminates the known corrosive effects of hydrogen fluoride will. Nevertheless, it is possible to introduce considerable amounts of fluorine into the catalyst and thereby Produce catalysts that are not only equivalent to the known catalysts, but even in their Effect are still superior.

The compounds of the above general formula include carbon tetrafluoride, Fluoroform, methylene fluoride and the corresponding sulfur compounds, with carbon tetrafluoride is preferred. Tetrafluorocarbon is an extremely stable compound and appears at first glance not as readily suitable for the preparation of fluorine-containing catalysts. Still, he proved himself as suitable and has advantages over other fluorinating compounds. Compared to For example, hydrogen fluoride is not corrosive

709 590/286

3 4

ding, easier to handle, easy in the steam - so preferably Al ₂ O ₃ with a large surface,

phase applicable, has a less damaging effect on, for example, a surface of at least

Aluminum oxide and is more suitable for producing 300 m ² / g, in particular at least 400 m ^a / g,

production of catalysts with a high fluorine content. measure by nitrogen adsorption according to the BET

Compared to alkyl fluorides of higher carbon number, 5 method. With such oxides, a preferred one becomes

for example tertiary butyl fluoride, while the fluorine content is at least 5.0 percent by weight and

Fluorination with the formation of less carbon or possibly more than 8.0 percent by weight

Carbon hydrogen deposits achieved on the catalyst. In general, the amount of fluorine is im

to be expected. Catalyst 1 to 15 percent by weight, based on

The treatment of the inorganic oxides with the io total catalyst, depending on the surface of the as

Fluorine compound is used under non-reducing catalyst support suitable oxides.

conditions_ made. NacrT an appropriate Also other inorganic oxides can under

Method, a stream of vapors will be halogenable alone or in the above conditions,

Mixing with an inert gas, e.g. nitrogen, or in so far as it is clearly the desired physical

Mixture with an oxygen-containing gas, e.g. air, has properties that are suitable for a catalyst

passed over the aluminum oxide. The vapors can be required for the conversion of hydrocarbons.

are circulated, and are appropriately borrowed. For example, refractory oxides from the

until all the fluoride is used up. On groups III to V of the periodic table, like the

in this way one has precise control over the oxides of boron, silicon, titanium or zirconium. Given

Amount of fluorine absorbed by the catalyst. Mixtures of two or more can also be used

The temperature, contact time and inorganic oxides used are used, being one

Amount of the fluorine compound affect the preferred by those which have a larger proportion of

Catalyst absorbed amount of fluorine, one containing aluminum oxide.

Each of these factors increases the amount absorbed. The catalyst contains a hydrogenating metal, amount increased. The temperatures are in the range 35 selected from Groups VIa and VIII of the Periodic of 300 to 500 ⁰ C, in particular from 350 to 45O ⁰ C, the system can be selected. Preferably, one and the treatment time is 5 minutes to the platinum group metal used in a 24 hours, particularly 10 minutes to 10 hours. Amount from 0.01 to 5.0 percent by weight, preferably. In general, for shorter treatment periods of 0.1 to 2 percent by weight, based on the total times, higher temperatures are used and the catalyst can be present. Swept from the metals. The amount absorbed must not be so high that the platinum group is too high for platinum and palladium to destroy the oxide structure. However, chromium, molybdenum, tungsten, recognizable by the X-ray diffraction pattern, or solid iron, cobalt or nickel alone or in several adjustable amounts of free fluoride or volatile and preferably in the form of the oxide or sulfide complexes of hydrogenating metal and fluorine can be formed 35 and in Amounts from 0.5 to 30 weight percent metal. It is assumed that the fluorine based on total catalyst are used. Linkage with the surface groups of the oxide For example, the catalyst can react 5 to 40 weight loss of one oxygen atom. Percent molybdenum oxide (expressed as MoO ₃ ) is a product of the reaction with carbon dioxide, for example, or without 1 to 10 percent by weight of a metal oxide and in certain cases water can also be given off from the iron group (expressed as divalent oxide). in particular cobalt oxide.

It is believed that the amount of fluorine that can be absorbed by the catalyst from a hydrogenating metal without maintaining the oxide structure is preferred to change this prior to treatment or to form further compounds on the surface with the fluorine compound in the halogenatable surface the specific surface 45 organic oxide incorporated, as this normally depends. It is 1.2 x 10 ~ ⁴ to 3.4 x 10 ~ ⁴ g / m ^2. wise catalysts of higher activity obtained To maximize fluorination of the available surface. If necessary, the oxide containing the surface group is the amount of fluorine in the hydrogenating metal size, before the treatment with an order of 3.4 · 10 -4, for example 3.0 to the fluorine compound dried and / or calcined 3.4 · 10 ~ ⁴ g / m ² . The fluctuation is on a possible 50.

small differences in the amount of surface The catalysts according to the invention can be used in

groups per unit area between in different processes for the conversion of hydrocarbons,

Way produced aluminum oxides. especially of petroleum hydrocarbons, where

Catalysts of high acidity which go beyond 3.4 · 10- "g / m ^{2 surface are required,}

The amount of fluorine means that reaction with the 55 will be used.

Alumina itself takes place or that the fluorine. I ₁

is not held sufficiently on the catalyst. example 1

These higher amounts are therefore preferably two 10 cm ³ samples of a commercially available catalyst

avoided. sators, made of platinum on aluminum oxide as a carrier

The fluorination up to the limit 60 given above consisted of 0.58 percent by weight of platinum and 0.81 percent of the weight percent chlorine contained only little or no reduction and a nitrogen surface, for example by no more than 10% adsorption according to the BET -Method measured above but an excess of fluorine has a larger surface area of 354 m ² / g, resulted in a standing reac reduction. Suitably, is therefore given factors which are kept at 350 ⁰ C and 1 hour, the difference between the surface of the originally were purged with dry nitrogen 65 which flowed through with sprünglichen aluminum oxide and the surface of 100 cm ^s / minute. They then became 10 fluorinated alumina not more than 10%. and 90 minutes with dry carbon tetrafluoride To achieve high fluorine contents is used (CF ₄₎ treated in a gaseous form, and finally a

flushed with dry nitrogen for a further hour. A third sample of the commercial catalyst was made treated at 350 ° C. with a stream of nitrogen which (at room temperature) is saturated with tertiary butyl fluoride until the degree of fluorination was the same as Sample 2. After cooling in nitrogen An analysis of the catalysts obtained resulted in the following values:

Treatment conditions Weight gain

Carbon content Weight percent

Fluorine content Weight percent

Sample 1: 10 minutes at 350 ^° C., CF ₄ amount 60 cm ³ / minute

Sample 2: 90 minutes at 350 ^° C., CF ₄ quantity 20 cm ⁸ / minute

Sample 3: 20 minutes at 350 ^° C., passing over with tert. Butyl fluoride saturated N ₈ at a rate of 40 cm ^s / minute

1.1
2.1

9.0

<0.01
<0.01

3.6

2.0 5.2

5.0

The values from the tables show the fluorine content, which increases with the treatment time, as well as the Advantage of using carbon tetrafluoride over tertiary butyl fluoride in terms of avoidance visible from carbon deposits.

Example 2

Example 1 shows the degree of fluorination which can be achieved at 350 ^° C. using CF ₁ . Hereinafter, the controlled fluorination is illustrated a larger sample of the catalyst at 35O ⁰ C under circulation conditions.

500 cm ³ of the commercially available platinum-aluminum oxide catalyst used in Example 1 were placed in an upright reactor and ^{flushed with dry nitrogen at 354 °} C. and a pressure of 8 kg / cm ² until the water content of the circulating nitrogen was below 10 parts per million lay. The pressure of the plant was then increased ^{to 9.3 kg / cm 2 with carbon tetrafluoride.} The gases were circulated for 10 hours. The CF ₄ content of gas samples taken after treatment times of different lengths is given below and shows the extent to which the fluorinating agent has been consumed.

CF, content
Sampling according to mole percent

0 hours -

0.5 hours 3.7

as 1 hour 2.0

2 hours 1.8

5 hours 1.1

10 hours 0.3

The fluorine content of the catalyst after the treatment was 6.3 percent by weight.

Example 3

The rate of fluorination depends in particular on the temperature. In this example, a treatment with CF ₄ ^{carried out at 450 °} C. is described (sample 4). As can be seen from the following values, a higher fluorine content with only one third of the amount of CF ₄ ^{was obtained in comparison to the treatment carried out at 350 °} C. (sample 2).

sample Treatment conditions carbon
salary
Weight percent fluorine
salary
Weight percent 2
4th Treatment of 10 cm ^{3 of} catalyst for 90 minutes
at 350 ^° C. with 20 cm ^{3 of} CF ₄ per minute
Treatment of 10 cm ^{3 of} catalyst for 30 minutes
at 450 ^° C. with 20 cm ^{3 of} CF ₄ per minute 0.01
0.02 5.2
7.6

Even at the relatively high treatment ^{temperature of 450 °} C., the structure of the original catalyst was not destroyed by the fluorination with CF _4. For example, no volatile substances containing aluminum or platinum were obtained, and the treated material still had the structure of ^ -aluminium oxide according to X-ray analysis. No crystalline platinum or aluminum fluoride structures could be found.

A catalyst prepared by passing a stream of dry air (2 volumes) and tetrafluorocarbon (3 volumes) at 550 ° C in an amount of 100 cm ³ / minute for 10 minutes had no isomerization activity. This _ss indicates the catalyst to a possible injury.

Example 4

The production of a larger amount of catalyst at the higher treatment temperature of 450 ^° C. is described.

200 cm ^{3 of} a commercially available catalyst, which consisted of platinum on aluminum oxide, contained 0.58 percent by weight of platinum and 0.81 percent by weight of chlorine and had a surface area of 354 m ^a / g, measured by nitrogen adsorption according to the BET method, was 1 hour at 456 ⁰ C with dry nitrogen, which was carried out at 12 l / hour, flushed. The catalyst was then V for ₂ hours

7 8

Treated with dry CF ₄ , which with 12 l / hour The surfaces measured by the BET method

flowed through. In conclusion, the catalyst was only different from the fluorinated catalysts

flushed with nitrogen for another hour and then little, if at all, of the surface of the un-

cooled in nitrogen. treated catalyst, a sign of the upper

The fluorine content of the treated catalyst was 5 surface fluorination. In this case the fluo-

9.3 percent by weight, its surface area 322 m ² / g, but the degree of gelling is approaching a limit. this

measure by nitrogen adsorption according to the BET-confirmed another experiment in which three separate

Method. 100 cm ³ samples of the original platinum aluminum

Example 5 oxide catalyst with 100 (1 volume), 200 (2 Volu-

ίο men) or 400 cm ³ (4 volumes) of an HF solution

In this example, the fluorination is treated with Tetra at a concentration of 4 percent by weight

fluorocarbon by the method according to the invention. It can be seen that a limit of

discovery with the fluorination with aqueous fluorine - 6.1 percent by weight of fluorine was achieved,

compared to hydrogen. ■ Fluorine content of the

70cm ^{3 of a} commercially available platinum-alumina volume of the 4 ^U / _O catalyst

Catalyst containing 0.58 weight percent platinum and. HF solution percent by weight

Containing 0.8 percent by weight of chlorine, 100 cm ^{3 were} 4.6 for 1 hour

flushed at 500 ⁰ C with dry nitrogen and then 2OO cm ³ 6.1

divided into seven parts of 10cm ³ each. Each part was for 400 cm ³ 61

different lengths of time from 0 to 80 minutes at 450 ⁰ C 20. '

Treated with dry CF ₄ dampers, which were carried out with successive impregnations at HF speed of 50 cm ³ / minute, gave solution among the treatments used. The following degrees of fluorination were found to have very little further increase under conditions: the fluorine content. Rather, under these circumstances

The fluorine content of the ² 5 would result in severe damage to the catalyst

Time ¹ of Behnndlune with CF catalyst considerable reduction of the surface and platinum

' ^Λ percent by weight led to crystallite formation.

The superior effect of an inventively using

0 minutes 0 CF ₄ prepared catalyst against one with HF

5 minutes 2 4 ³ ° ^ner g ^este H ^th catalyst is of the following encryption

'immediately apparent:

10 minutes 3.0 _Tr ..., _v .

Preparation of the catalyst A

20 minutes 6.0 _{65 g thin} fine-grain commercially available platinum

30 minutes 8.0 35 .Aluminum oxide mixture with a content of

0.58 percent by weight platinum and 0.81 percent by weight

40 minutes 9.0 chlorine and a surface area of 440 m ² / g

80 minutes 10 3 " ¹ ^ 100 ml of a 5% aqueous hydrogen fluoride

'Acid solution at 0 ⁰ C for a period of 30 minutes

40 impregnated. The mixture is then at 12O ⁰ C for

The measured by the BET method over the period of 4 hours dried. The fluorine surfaces of the fluorinated catalysts gave way to all the content of the catalyst is 6 percent by weight,
by no more than 10% of the surfaces of the _rT ",", _η

Enclosed catalyst (440m ² / g) from, a sign, production of catalyst B

that the fluorination is essentially a surface 45 The same platinum-alumina mixture as appearance was. used in the manufacture of catalyst A,

In another experiment, a further one was carried out by treating with dry tetrafluorine charge of the original platinum-aluminum oxide carbon ^{gas at a flow rate of catalyst at 500 °} C. with dry nitrogen at 150 ml / minute for 20 minutes at an initial rate, whereupon 10- cm ³ samples each V ₂ hours at a reaction temperature of 440 ⁰ C fluorinated. The fluorine-O ⁰ C with the same amount of HF solutions under-. The content of the catalyst is then 5.0 weight different concentrations from 0.5 to 5 weight percent.

percent were treated. After filtration, drying portions of both catalysts are then used

at 12O ⁰ C and lstündigem heating at 500 ⁰ C in a stream of dry nitrogen once for moving nitrogen following fluorination were 55 detected the period of 10 minutes and once for the grade: fluorine content of the period of 60 minutes at 500 ⁰ C more calcined.

Catalyst Each of the catalysts so prepared is then

Concentration of the HF solution in percent by weight with respect to its isomerization and cracking activity

tested a hydrocatalytic process, with 0.5 weight percent 0.9 60 worked under the following process conditions

1 weight percent 1.6

2 weight percent 2.5 starting material n-hexane / hydrogen

, "..,. , "" Temperature 300

3 percent by weight 4.0 65

Pressure normal pressure

4 percent by weight 5.3 ",., ...

Space velocity,

5 percent by weight 6.0 v / v / hr 0.5

ίο

The observed values for catalysts and process results are in the table below specified:

Catalyst A | Catalyst B Duration of the calcination at 500 ^° C. in minutes

10 I 60 I 10 60

Catalyst fluorine content, percent by weight

Hydrogen, weight percent

Surface area, m ^a / g

Procedural results

Total conversion, weight percent

Hydrocracking (accumulation of C ₆ and lower hydrocarbons)

Isomerization (accumulation of C _e -isoparaffins,
Weight percent)

Selectivity for isomerization (total isomers of total conversion)

5.8
0.25
393

76.7

7.6

69.1

90.1

5.2 0.19 418

74.5

4.2

70.3

94.4

5.0 0.12 414

78.2 14.7 63.5 81.2

From the table it can be seen that the catalyst B, which the process according to the invention in Her- as Position corresponds, provides values that are not only comparable to catalyst A, but in some cases even considerably superior to it. In addition, it must be taken into account that this catalyst B in its fluorine content is not insignificantly below the corresponding value of catalyst A.

Claims (3)

Claims: 35 1. Process for the production of aluminum oxide, fluorine and a hydrogenating metal of VI. Subgroup and VIIT. Group-containing hydrocarbon conversion catalysts, by halogenation of activated aluminum oxide with halogen-containing organic compounds under anhydrous conditions at elevated temperatures, characterized in that under non-reducing conditions at temperatures of 300 to 500 ⁰ C and contact times of 5 minutes to 24 hours with gaseous fluorine compounds works that correspond to the following general formula: ρ Y-X-F wherein X is carbon or sulfur and Y is fluorine or hydrogen, and in that it introduces the fluorine in amounts of 1.2 x 10 ~ ⁴ to 3.4 x 10 ~ ⁴ g / m ² surface in the catalyst. 2. The method according to claim 1, characterized in that one with tetrafluorocarbon is working. 3. Process according to Claims 1 and 2, characterized in that aluminum oxide with a surface area of at least 300 m ² / g is used and the fluorine content of the catalyst is at least 5.0 percent by weight. Documents considered: French Patent Specifications No. 1174 768,1080 916. Older patents considered: German Patent No. 1194 378. 709 590/286 6.67 © Bundesdruckerei Berlin