DE2059619A1 - Isomerization of olefins - Google Patents

Description

DR. BERG DIPL.-ING. STAPF

PATENT ADVOCATES 9 Π £ Q C 1 Q

8 MUNICH 2. H ILBLESTR ASSE 2O '

Dr. Berg Dipl.-Ing. Stapf, 8 Munich 2, Hllblestrofle 20

Your reference Our reference date

^r a Dec, 1970

Attorney's file 20 198
Be / A

Esso Research and Engineering Company Linden, I.J. (UNITED STATES)

"Isomerization of Olefins"

The invention relates to the catalytic isomerization of olefins and, more particularly, to a process for converting normal butenes to isobutene. Isobutene is a valuable olefin that can be used as a starting material in the manufacture of a variety of valuable, commercially available

-2-

1 09824/2263

copy

_ ρ -

Products serves. It is therefore important to be a technical one feasible and economical process for isomerization of n-butenes to isobutene is available to have"

The process according to the invention can also be used to isomerize other olefins with up to 20 carbon atoms, especially those with 5 or 6 carbon atoms, can be used during skeletal isomerization as well a shift of the double bond takes place depending on the thermodynamic equilibrium conditions »

It is also possible to process selective fractions of various natural oils. These can be used as individual compounds or as fractions with a certain boiling range by selective fractionation and Distillation of catalytically cracked gas oil or steam cracked Gasoline to be separated.

For example, a steam-cracked C. riaphtha cut be subjected to the method of the invention either before or after that present in the incision Isobutene has been removed. In the latter case the mixture is mainly normal butenes, the corresponding ones Contains paraffins and inert gases.

So the process can be applied and used for conversion

-3- 109824/2263

_ 3 -

are used by isomerizable, olefinic hydrocarbons, when these isomerizable olefins are present in minor amounts in various refinery streams are·

Accordingly, the invention provides a process for the catalytic isomerization of an isomerizable olefin, in which the olefin is dispersed at a temperature of 300 to 600 ^° C. and a pressure not exceeding 10 atmospheres with a metal from group VIII of the periodic table or a corresponding metal compound Alumina with a surface area of 100 to 300 m / g at a throughput rate of 0.1 to 10, expressed as liquid volume / catalyst volume / hour, in contact. Preferably platinum, palladium and nickel are used

The process can also be used to isomerize such isomerizable olefins if they are in admixture with other olefins, paraffins and inert gases.

The preferred metal compound is chloroplatinate, the need not be reduced to the metal.

Similar catalysts have already been proposed to carry out specific reactions, such as powerforming,

-4-109824 / 2263

_ A -

but they are not for the skeletal isomerization of normal olefins, like η-butene, suggested

The reaction conditions are selected in such a way that the yield is as close as possible to the theoretical one Yield is based on the thermodynamic information can be derived «

At relatively low temperatures, the conversion takes place relatively less, at relatively high temperatures the conversion increases, but a practical limit is the onset of side reactions such as polymerization and cracking, and so there is an optimal conversion at a given temperature, which corresponds to the amount of isobutene at this temperature under theoretical equilibrium conditions «

The temperature ranges given above indicate the most suitable temperature values within a broad framework ^: which lead to a satisfactory result and which can be set for each reaction in accordance with the other reaction conditions, such as throughput rate. A preferred temperature range is 400 to 500 ⁰ G, this range being particularly suitable for converting normal butenes at pressures not higher than 10 atmospheres «

At higher pressure, the risk of polymerisation begins

-5- 109824/2263

tion reactions to increase, so that the pressure should suitably be kept lower than that indicated above Value, and atmospheric pressure is preferable for technical purposes «,

The supported catalyst is used on a plague bed in the reaction vessel and the olefins are passed through this bed is directed at different throughput rates. In general, the throughput of the olefins expressed in liquid volume / catalyst volume / hour, the throughput rate being in the range of 0.1 to 10.

The volume of liquid is that measured under standard conditions, namely room temperature and atmospheric pressure Volume of olefins.

The amount of metal or metal compound in the catalyst can be from 0.05 to 2% by weight based on the dried Catalyst, with amounts from 0.3 to $ 1 being preferred.

The catalyst can be prepared in various ways, including the support material, commonly referred to as Gamma aluminum oxides, with the metals either by precipitation or impregnation combined. It is suitably used in the form of extrudates or pellets. Of the

-6- 109824/2263

Carrier is preferably used in a very pure state, without the content of any appreciable amounts of impurities Preferably it has a purity of at least 99> 8% by weight on a dry weight basis

It has been found that it is advantageous to _o supply a small amount of hydrogen to the olefin stream This addition is effective in a continuous process for extending the operating life of the catalyst. In general, the amounts of hydrogen not exceeding 10 VoI ₀ ^, and it is _"o $ sufficient to increase the service life of the catalyst to increase significantly higher amounts, up to 50 volume" to 6 VoI generally 2 $ can be used, but is characterized no economic advantage achieved »

example 1

n-butene (1) was combined with a platinum catalyst supported on alumina, isomerisierto The existing in the dry catalytic amount of platinum was 0.3 wt _o $. The catalyst consisted of small pellets 1.6 mm in diameter with an average length of 4 mm. None of the pellets was less than 1 mm _o The surface area was 180 m / g and pore volume 0.50 ml / g "The aluminum oxide had a purity of 99" 9 wt. ^A / o, sbasis based on dry weight. A stainless steel reaction vessel with a capacity of 100 ml was filled with the catalyst

-7-

109824/2263

- Ύ -

Pellets Filled "The olefin was passed through a preheat system heated to 500 G and then through the reaction vessel heated to 500 ⁰ G at a flow rate of 1.6 liquid volume / catalyst volume / hour. Atmospheric pressure was used" Mach the reaction was collected, the polymeric material formed in a balloon, equipped with a water condenser _o the gases were in a gas meter measured, collected in a glass bottle and introduced in a device for identifying GLC

The following results were obtained (in wt. $):

Isobutene yield 32.5

Conversion of n-butenes to isobutene and by-products 40.4

Selectivity of the n-butenes to isobutene 80.5

Amount of cracked products 5.1

Amount of polymer 2.8

The results show that the isobutene yield is close to the theoretically possible yield, which in turn according to the thermodynamic equilibrium in the prevailing Reaction conditions (at about 36 ^) and that the losses caused by cracking and polymerization were relatively low

-8- 109824/2263

After the reaction, the catalyst was regenerated by (by burning off the carbon and Polymerisatablagerung), that a mixture of air and nitrogen (in volume ratio of 1: 4) for 2 hours at 50O ⁰ G introduced into the catalyst.

This treatment completely regenerated the catalyst and could be reused _{or the like}

Example 2

Example 1 was, but with the reaction temperature of 400 G and a throughput rate of 0.45 liquid volume / catalyst volume / hour, repeated. The reaction was carried out in the same apparatus and in the same manner as described in Example 1, and the following results (in G-ew. $) were obtained:

Yield of isobutene 33 »2

Conversion of n-butenes to isobutene

and by-products 47 »4

Selectivity of the n-butenes to isobutene 70.1

Amount of cracked products 8.2

Amount of polymer 6.0

Theoretically possible yield in this case was about 39%, and therefore it was that caused by disintegration Losses relatively low

-9- 109824/2263

Example 3

Example 1 was repeated, but instead of n-butene-1 Trans-butene-2 isomerized. The throughput speed in this case was 0.83 liquid volume / catalyst volume / hour, and the temperature was 500.degree

The reaction was carried out in the same apparatus and in the same manner as described in Example 1, and the following results (in weight "$) obtain:

Isobutene yield 26.7

Conversion of n-butenes to isobutene

and by-products 40.7

Selectivity of the n-butenes to isobutene 65.6

Amount of cracked products' 11.3

Amount of polymer 2.7

The theoretically possible yield is 36 wt. #,

Example 4

Trans-butene-2- was isomerized in the same way as indicated in Example 3, but the throughput rate in this case was O _f 45 liquid volume / catalyst volume / hour and the reaction temperature was 40O ⁰ G.

The following results (in wt. ^) Were obtained:

-10- 109824/2263

Isobutene yield 32.7

Conversion of n-butenes to isobutene

and by-products 47.8

Selectivity of the n-butenes to isobutene 68.3

Amount of cracked products 11.6

Amount of polymer 3.5

The theoretically possible yield is 35% by weight, from which to it can be seen that the losses due to side reactions are relatively low »

Example 5

n-pentene (1) was isomerized with the platinum catalyst supported on aluminum oxide, as described in Example 1

A stainless steel reaction vessel with a capacity of 100 ml was filled with catalyst pellets. The olefin was passed through a preheater at 400 G and then through the reaction vessel ^{heated to a temperature of 400 0} G at a flow rate of 3.1 liquid volume / catalyst volume / hour. Atmospheric pressure was used. After the reaction, the product was collected in a balloon equipped with a water condenser. A sample was applied to a GLC device for analysis.

The following results (in weight ^) were obtained:

109824/2263 -n-

Yield of isoamylenes 60.2

Conversion of n-pentenes to isoamylenes and by-products 69.3

Selectivity of the n-pentenes with regard to isoamylenes 86.8

Amount of cracked product 5 »6

Amount of polymer 3.5

The theoretically possible yield, determined by thermodynamic Equilibrium, under the prevailing reaction conditions, was 69 ^ c

Example 6

Example 5 was repeated except that the reaction temperature was 450 0 and the flow rate was 2.2 3 liquid volume / catalyst volume / hour _e The reaction was carried out in the same manner as in Example 5, and the following results were obtained (Ln wt · ^) obtain:

Yield of isoamylenes 58.5

Conversion of n-pentenes to isoamylenes and by-products 74.3

Selectivity of the n-pentenes with regard to isoamylenes 78.7

Amount of Kraek products 9 »4

Amount of polymer 6.5

The theoretically possible yield in this case was 74.0% .

109824/2263 -12-

Example 7

A comparative experiment was carried out using aluminum oxide instead of the platinum catalyst supported on aluminum oxide used alone. It seems that the conversion of η-butene falls off faster than when the supported Platinum catalyst used. The experiment was carried out in such a way that aluminum oxide with a Purity of 99.9 G-ew. $ On a dry weight basis, and the catalyst according to Example 1 used.

n-Butene (1) was isomerized as described in Example 1, but the reaction temperature was 400 G and the Throughput rate 0.5 volume of liquid / volume of catalyst / hour at atmospheric pressure »

After 30 hours the n-butene conversion was 15.4 (vs. 50.3 after one hour) for the alumina catalyst, while for the platinum-alumina catalyst the n-butene conversion was still 30.6 after 30 hours (compared to 54.6 after one hour). The isobutene yields were in in both cases: 30.8 (after one hour) and 11.1 (after 30 hours) for aluminum oxide and 30.3 (after one hour) and 19 »7 (after 30 hours) for the platinum-alumina catalyst (all results in G-ew. #).

-13- 109824/2263

Claims (1)

- 13 claims: ί 1 β Process for the catalytic isomerization of an isomerizable olefin, characterized in that the olefin is ^{dispersed at a temperature of 300 to 600 0} C with a metal of group VIII or a compound of this metal, on aluminum oxide with a surface area of 100 to 300 m / g, at a lysatorvolumen Durchaatzgeschwindigkeit.-from 0.1 to 10, expressed as volume of liquid / catalogs _Λ / hour, brought into contact " 2 »Method according to claim 1, characterized in that the metal used is platinum, palladium or mekel isto 3β method according to claim 1, characterized in that the metal compound used is chloropiatinate. 4. Process according to one of the preceding claims, characterized in that the process is carried out at a temperature of 400 to 500 ^° C. at pressures not higher than 10 atmospheres. 5. The method according to any one of the preceding claims, characterized in that the amount of metal or metal compound in the catalyst is 0.05 to 2 wt _e #, based on the weight of the dried catalyst. <-14- 109824/2263 2Q59619 Process according to one of the preceding claims, characterized in that a catalyst is used in which gamma-aluminum oxide is combined with metals of group VIII by precipitation or impregnation _{or the like} 7ο Method according to one of the preceding claims, characterized characterized in that the catalyst is used in the form of extrudates or pellets 8ο Method according to one of the preceding claims, characterized in that a catalyst is used in which the aluminum oxide has a purity of at least 99.8 GeWo / £, based on dry basis, " _% 9ο Method according to one of the preceding claims, characterized characterized in that the olefin stream is 10 Vol <·? supplies not exceeding amount of hydrogen » 10 «, method according to one of the preceding claims, characterized characterized in that containing isomerizable olefins Refinery streams are used, 11o method according to any one of the preceding claims, characterized in characterized in that isomerizable olefins containing up to 20 carbon atoms are used. 12e method according to claim 11, characterized in that that n-pentenes or n-butenes to the corresponding Iao- 109824/2263 - 15 olefins are converted _e 13 · Process for the catalytic isomerization of an isomerizable Olefins according to claim 1, essentially as described in the examples. 109824/2263