DE1204645B - Process for isomerizing C- and / or higher-boiling paraffinic hydrocarbons in the gasoline boiling range - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

- GERMAN

PATENT OFFICE

EDITORIAL

Int. C:

C07c

Clog

German class: 12 ο -1/01

Number: 1204 645

File number: B 63362IV b / 12 ο

Filing date: July 21, 1961

Opening day: November 11, 1965

The invention relates to the isomerization of gases boiling in the gasoline range (i.e. up to 204 "C) Q-paraffinic hydrocarbons and higher paraffinic hydrocarbons, especially the isomerization of pentanes and / or hexanes. The term "isomerization" includes both conversion of normal paraffins into isoparaffins as well as the conversion of isoparaffins into isoparaffins higher degree of branching.

The isomerization of normal paraffins is gaining ground in the development of high-octane motor fuels ever greater importance. So far, the desired increase in octane number has mainly been achieved with the help of catalytic reforming processes that reduce the aromatic content of the Increase gasoline. With the increase in the compression ratio of modern engines, it results however, the desire for other ways to increase the octane number of the fuel. It is known that contains the used in the catalytic reforming process Petrol substantial amounts of low-boiling normal paraffins. It is evident that through Conversion of these normal paraffins into isoparaffins achieves a considerable increase in the octane number would.

The use of aluminum halides as catalysts for the isomerization of normal paraffins is of course well known, but the process requires a continuous supply of catalyst to the reaction zone and is not entirely satisfactory when normal pentane and / or normal hexane to be treated after him.

It is known to use noble metal supported catalysts for the isomerization of normal paraffins, however, this requires high temperatures at which the equilibrium is related the desired isomers, d. H. the isomers of the highest octane number, is unfavorable.

An isomerization process is also known in which a catalyst composed of an aluminum halide and a hydrogenating metal on a refractory oxide is used as a carrier. From British patent specification 822 998 a method for producing such a catalyst is known. Here, aluminum chloride or bromide is evaporated onto a previously prepared mass, which consists of a refractory oxide and a hydrogenating metal from group VI (A) or VIII of the periodic table, and then the mass treated in this way at a temperature above 300 ⁰ C treated until practically all of the unreacted aluminum chloride or bromide therefrom ent-Process for isomerizing C ₄ -
and / or higher-boiling paraffinic hydrocarbons from the gasoline boiling range

'Applicant: ·

The British Petroleum Company Limited,
London

Representative: .

Dr.-Ing. A. v. Kreisler, patent attorney,

Cologne 1, Deichmannhaus

Named as inventor:
Peter Thomas White,

Paul Anthony Lawrance, Sunbury-on-Thames,
Middlesex (UK)

Claimed priority:

Great Britain July 29, 1960 (26,467)

is distant. The preferred upper temperature limit is 700 ^° C.

It has now been found that the precise temperature used is important when using this method. If the temperature is too low, not all of the unreacted aluminum halide will be removed and may be given off and deposited in the colder parts of the plant during a subsequent isomerization process. An example of this are well-known catalysts that have been prepared at a temperature of about 250 ⁰ C. Too low a temperature can also result in a catalyst having low isomerization activity. On the other hand, if the temperature is too high, a considerable drop in the isomerization activity of the catalyst can also occur. This is surprising as the temperature in question is not high when compared to the temperatures normally used in catalytic conversion processes. It is, for example, below the temperature of the catalysts when a hydrogenating metal on aluminum oxide is normally exposed in reforming processes (for example temperatures in the range of 600 ° C.).

The exact reason for this loss of isomerization activity is not known with certainty, there however, it is possible that due to the presence of

509 737/384

3 4

Aluminum chloride migration and accumulation of aluminum alcoholate has been produced. The platinum can take place at lower temperatures than hydrogenating metal in any suitable stage it is normally to be expected. It is also possible, during or after the production of the aluminum, that a loss of platinum due to the formation of volatile oxides, e.g. B. during hydrolysis, occurs in an on-platinum complex. 5 slurry or a gel of the hydrated aluminum object of the invention is accordingly a minium oxide or, after calcination, into which _{catalysts are incorporated for isomerization of C 4} and / or higher. If a metal boiling paraffin hydrocarbons of the gasoline group of the platinum group is used as the hydrogenating metal boiling range in the presence of hydrogen, the addition is preferably carried out by precipitation using catalysts, the aluminum i ° of the metal from a solution with hydrogen sulfide, halide and a hydrogenating agent Metal on Preferably, a refractory oxide carrier, preferably aluminum, is used for the process, which for the most part consists of pentanes, minium oxide, and, after the introduction of the hexanes or a mixture of these paraffins, consists. Aluminum halide of a heat pretreatment. Particularly preferred is an insert which has been subjected to a temperature above 300 ° C., which thereby contains a larger proportion of hexanes. If it is only intended to indicate that normal paraffins are used as catalysts, the one in which the heat pretreatment was initially carried out as a treatment to separate the temperature range from 343 to 399 ° C. normal paraffins from the other hydrocarbons can be used. A temperature-is subjected materials particularly preferred, whereupon the Normalratur to 371 ⁰ C. For the preparation of the catalytic converters 20 paraffins to the isomerization catalyst in infatuate is no protection are brought stirring in the invention. This separation can be claimed in. simple way with hooves of so-called molecular

The aluminum halide is preferably made on the sieve.

Heat-resistant oxide is added, which already contains the product of the isomerization reaction can be converted into hydrogenating metal. It can expediently be treated in the same way so as not to be added to the catalyst by separating it off with normal paraffins which have been added and which can be returned to the aluminum halide vapors alone or as a mixture of isomerization reaction, with an inert gas, ζ. B, nitrogen, in contact This separation, too, can expediently be carried out with moles. The removal of unreacted kularsieben can be made. Aluminum halide can then or at the same time take place at the same time. It is advantageous if the use is free of sulfur, ie the catalyst can be in counter-water and aromatic hydrocarbons. wait of aluminum halide vapors to 343 to The isomerization can be heated under the following conditions -399 ° C until a state of equilibrium is reached in the liquid or vapor phase. A simple method of treatment will be:
of the catalyst with aluminum halide vapors 35 - ^. _Λη , ~ _nA ° r *

is a stream of vapors and inert. Temperature 10 to 204 C

to pass gas over the catalyst, while the Ent- preferably 66 to 177 C

Removal of unreacted aluminum halide Pressure normal pressure up to 141 kg / cm ²

is advantageously made so that an inert gas - preferably 16 to 71 kg / cm ^a

current at the required temperature over the 40 room air flow:

Catalyst is passed. speed ... 0.05 to 10 V / V / h,

The duration of the heat treatment in the specified "is preferably 0.2 to 5 V / V / h Temperature range is not critical. It only has to be rich in water from the molar ratio, to convert the unreacted aluminum halide to carbon

to remove. The duration of treatment is preferred 45 hydrogen 0.01 to 20: 1,

wise at least 2 hours, in particular at least - ^: preferably 1.5 to 15: 15 hours, however, an extension of this period of time up to at least 16 hours does not have any subsequent effects aluminum chloride, which forms it under the reaction conditions, is used as the halide, but aluminum bromide cannot be used either directly or through addition. Preferably, the aluminum halide or the hydrogen-containing gas used will be introduced into the heat-treated catalyst in an amount of the reaction zone. The halogen-3 to 20 percent by weight, based on the cata- hydrogen, is preferably used in an amount up to lysator. 55 1 percent by weight, based on the insert, present.

All metals of groups VIa and VII of the example which are known to be effective can be used as the hydrogenation metal. Periodic table can be used. Preferred . A reforming catalyst that is made from a MetaE of the platinum group, specifically platinum. , _ _., _., .... or palladium, in an amount of 0.01 to 60 _O J2 g ^ew i ^c jfP ™ ² ^^ ^ün . ' From 0.3 to 1.5 overall ⁹ ^ ⁶ J per cent by weight and Alummiumoxyd wight percent, can be present 5.0 percent by weight, preferably. It has been found fixed ° ^'75 weight percent chlorine, that, contrary to previous data platinum and consisted was 2 hours at 482 ⁰ C under nitrogen, palladium efficacy are substantially equivalent with respect to the hydrogenated and then dried for 2 hours at 482 ° C metals. 65 reduced under hydrogen. The catalyst was As already mentioned, preferably aluminum is then used at 204 ° C with vapors of anhydrous aluminum oxide as a heat-resistant oxide and carrier, minium chloride impregnated by a nitrogen stream, an aluminum oxide, which was contained from one of the aluminum chloride vapors, is preferred for a time -

5 6

was passed over it for a long time, which cut twice the time from a Cs-Ce light petrol. The middle ones

that the aluminum chloride fumes needed are working conditions in all activity tests

to appear for the first time behind the catalyst bed. given in Table 1 below.

The impregnated catalyst was in four parts

divided up. Part (A) was not treated any further. 5 Table 1

The other three parts were heated for 10 hours at 132 ° C different temperatures in a nitrogen stream

held to pressure excess aluminum chloride to 17.5 atu

remove. For part B, the temperature was the molar ratio of hydrogen to

288 ° C, for part C 371 ° C and for part D 454 ° C. Hydrocarbon 2.5: 1

Each of the four parts was set to its isomerization space flow rate of 0.5 V / V / h

activity was tested in an experiment in which the reactor was operated in a straight pass with downward flow. A product was used that was determined by gas chromatographic anatrysize, desulphurized and dearomatized hexane analysis, which is shown in Table 2 below.

Tabel

Catalyst B I C

Final heat treatment, ⁰ C

running time

Product composition in percent by weight

C ₁ -C _{4 paraffins}

C _B paraffins

C ₆ paraffins

Naphthenes

C _e fraction of the product in percent by weight

2,2-dimethylbutane

2,3-dimethylbutane

2-methylpentane

Cyclopentane

3-methylpentane

n-hexane

mission

100

no
to 55

0.5
2.5
93
4th

29.5
43.5

16.5
10.5

288
until 12

track
1.5

93
5.5

100
28.5
40.5

19th
12th

371 37 to 41

track

2 92

100 29 40.5

18.5 12

454 43 to 47

track

93.5 5.5

100

21 43

21 15

100

100

100

100

454 36 to 40

0.5 2 93

100 21 44

20.5 14.5

100

It can be seen that the 10 hour heat treatment at 454 ° C. considerably reduced the activity of the catalyst for the formation of the most desirable isomer, 2,2-dimethylbutane. Parts A and B had high activity, but after the experiment aluminum chloride was found to settle in the lines after the catalyst bed, an indication that the catalysts contained excess removable aluminum chloride. Part C, on the other hand, which ^{had been heated to 371 °} C., not only had a high activity, but also gave no deposits in the lines behind the catalyst bed.

Example 2

The experiment described in Example 1 was repeated, but in this case the impregnated one was used Catalyst divided into seven parts. Each TeE was 10 hours at different temperatures heated in a stream of nitrogen to remove excess aluminum chloride. Every part became then tested in the same manner as in Example 1 for its isomerization activity. The ones for heat treatment temperatures used and the results obtained in the activity tests listed in Table 3 below.

Table 3

temperature Chloride content
of 2,2-dimethyl Activi the warmth butane content would you do treatment
° C js.ataiysators
in weight
percent of the product in
Weight percent mission 2.0 1 316 12.75 28.0 2 343 11.3 31.0 3 371 12.2 31.0 4th 399 9.85 31.0 5 429 10.9 27.0 6th 454 9.5 26.0 7th 593 7.0 15.0

These results are similar to the results of Example 1 and indicate that the activity of the catalyst decreases when temperatures of ° C and more are applied in the heat treatment will. In addition to the tendency to release aluminum chloride, which is in the lines behind the Catalyst bed settled, had the catalyst that

which had been subjected to the heat treatment at 316 ° C also had a lower activity.

Claims (4)

Patent claims: 1. Process for isomerization of C ₄ - and / or higher-boiling paraffinic hydrocarbons of the gasoline boiling range in the presence of hydrogen using catalysts which contain aluminum halide and a hydrogenating metal on a refractory oxide carrier, and after the introduction of the aluminum halide, a heat pretreatment above 300 ° C under-. have been thrown, characterized in that catalysts are used in which the heat pretreatment has been carried out in the temperature range from 343 to 399 ° C. 2. The method according to claim 1, characterized in that worked with catalysts containing aluminum oxide as a support material will. 3. Process according to Claims 1 and 2, characterized in that catalysts are used which after the heat treatment contain 3 to 20 percent by weight of aluminum halide. 4. The method according to claims 1 to 3, characterized in that with a metal of the platinum group in amounts of 0.01 to 5 percent by weight containing catalyst is worked. Considered publications:
■ USA Patent No. 2,900,425; 2,924,629;
French patent specification No. 1 238 575. 509 737/384 1t. 65 © Bundesdruckerei Berlin