DE2728218A1 - PROCESS FOR ISOMERIZATION OF 1-BUTEN INTO 2-BUTEN - Google Patents

Description

DR. GERHARD RATZEL PATENT ADVOCATE

File 8856

June 22, 1977

6800 MANNHEIM 1. Seckenheimer Str.36a, Tel. (0621) 406315

Po.t.ch.ckkonto: Frankfurt / M No. "293" 3 B ■ η k: DauOcha Bank Mannheim Nt. T · I · g r. - Cod ·: Qarpat T.I.χ 463670 Par * D

Institut Francaie du Fetrole

4, avenue de Bois-Preau

92502 Rueil-Malmaieon / France

Process for the isomerization of 1-butene into 2-butene

709881/0926

The invention relates to a process for isomerization ▼ on 1-butene in 2-butene.

Different chemical processes, e.g. the cracking of different petroleum fractions, produce C ₄ fractions _/ which contain a considerable amount of 1-butene. For certain purposes, however, it is preferred to obtain a higher content of 2-butene. Accordingly, it is an object of the present invention to isomerize 1-butene to 2-butene.

Butadiene is also found in certain batches. So it is beneficial to do it in some known way separated, e.g. by distillation or extraction with a polar solvent. Nothing-the-less exists after this treatment a substantial amount of residual butadiene and traces of the polar extraction solvent, traces sufficient to gradually remove poison the catalyst. A second object of the present invention is to simultaneously hydrogenate residual butadiene and isomerize of 1-butene to carry out in 2-butene without noticeably deactivating the catalyst.

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It is known to carry out these reactions in that

1-butene or a mixture of 1-butene and butadiene (which may contain other hydrocarbons, e.g. butane, Isobutane, 2-butene and isobutene) with a palladium catalyst on aluminum oxide in a hydrogen atmosphere in Brings contact.

Various difficulties have arisen, as described in particular in US Pat. No. 3,531,545:

- Excess hydrogenation, which leads to significant losses of olefins;

- Polymerization of highly unsaturated hydrocarbons, which leads to deactivation of the catalyst leads.

U.S. Patent No. 3,531,545 suggests overcoming these difficulties by adding sulfur compounds to the hydrocarbon feed. For this it is necessary to work at elevated temperatures between 135 ° and 26O ⁰ C, preferably between 163 ° and 190 ⁰ C; at these elevated temperatures, the thermodynamic equilibrium in the conversion of 1-butene into 2-butene is unfavorable. In addition, poly-

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At these temperatures the isobutene merges as it does for example, U.S. Patent 3,772,400, which reduces the selectivity of the isomerization reaction will. Finally, in the presence of sulfur, one usually has to use an increased amount of hydrogen and remove the sulfur at the end of the operation.

The present invention overcomes the disadvantages of the known methods. You make it possible to isomerize 1-butene at lower temperatures than it is with the known processes was possible, and accordingly an abruptly higher conversion into 2-butene is obtained. The rate of reaction is increased, even at these relatively low temperatures. The hydrogenation of olefins in saturated Hydrocarbons is negligible. The sensitivity of the catalyst to poisons is in proportion reduced to the use of precious metals without the pretreatment according to the invention. Finally, the polymerization reactions are prevented.

The inventive method for the isomerization of 1-butene consists in

(A) bringing a sulfur compound into contact with an isomerization catalyst which is a noble metal Contains group VIII of the periodic table of elements,

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(b) that you then the catalyst with hydrogen Bringing in contact and

(c) that the catalyst obtained in step (b) is brought into contact with 1-butene in the presence of hydrogen, wherein the 1-butene is isomerized into 2-butene.

As described above, 1-butene can be used alone or in admixture with one or more hydrocarbons use, in particular one or more of the following hydrocarbons:

-Butadiene;

-2-butene (ice and / or trans); -Isobutene;

-Butane and isobutane

If butadiene is present, it is hydrogenated in butene, which is an advantage of the present inventive method.

The presence of compounds in the batch that are capable are to deactivate or selectivate the catalyst e.g. sulfur or nitrogen compounds, is undesirable;

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In fact, as described above, in the presence of such compounds it is necessary to work at elevated temperatures, that is to say under conditions which are unfavorable for the isomerization. Accordingly, it is preferable that the charge less than 5 ppm in terms of moles of sulfur or nitrogen contains, preferably less than 1 ppm in moles of sulfur or nitrogen (ppm = parts per million).

The isomerization temperature is usually between 50 and 140 ^° C., preferably between 65 and 120 ^° C. and in particular between 70 and 110 ^° C. The lower the temperature, the more favorable the thermodynamic equilibrium is in order to obtain an increased amount of 2-butene .

The pressure can be selected in a wide range, for example from approximately 1 to 50 bar overpressure (atg), preferably from 5 to 30 bar overpressure (atg). The best results are obtained if 1-butene is kept, at least for the greater part, in the liquid phase and preferably practically all in the liquid phase. The pressure can be achieved by means of hydrogen or a mixture of hydrogen and an inert gas. The throughput of 1-butene is usually 1 to 50 1, preferably 5 to 20 1 (in the liquid state), per liter of catalyst and per hour. The hydrogen is usually supplied at a rate of from 0.1 to 15 moles per hundred, preferably from 1 to 10 moles per hundred in proportion

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to the 1-butene or the mixture of 1-butene and butadiene ▼ used.

The catalyst contains at least one noble metal from Group VIII of the Periodic Table of the Elements, i.e. ruthenium, Rhodium, palladium, osmium, iridium and / or platinum. Platinum is preferred because of its greatest selectivity. Any of the known carriers can be used, e.g. Alumina, (the preferred carrier), silica-alumina and carbon. A preferred catalyst Contains 0.01 to 2% by weight of palladium on aluminum oxide. The invention does not apply to these catalysts or these Types of catalysts limited by precious metals. Commercially available catalysts can be used, e.g. Catalysts C-31 from Catalysts and Chemicals, G-55 from Girdler Corporation, or preferably LD-265 from Societe Francaisedes Produits pour Catalyse.

According to the invention, the catalyst is treated with a sulfur compound, then with hydrogen before it is used as a catalyst. However, it is not necessary that the catalytic metal is in the reduced state when used in this mode of treatment; one can also work with the catalyst, which contains the precious metal in a bound state, e.g. as an oxide. Man

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uses an excess of the sulfur compound, i.e. at least two moles (gram atoms) of sulfur and e.g. 5 to 100 Moles or more (gram atoms) of sulfur per mole (gram atoms) of precious metal.

According to a preferred procedure, the sulfur compound is allowed to flow until it is no longer retained by the catalyst. The temperature in this treatment catfish is usually above 20 ⁰ C _1, for example at 50 to 400 ⁰ C or above, preferably at 80 to 130 ⁰ C. The sulfur compound may be used alone or diluted in a gas may be used, such as nitrogen, argon or hydrogen ; this latter gas is preferred. The sulfur compound can also be introduced in liquid phase or vapor phase.

The sulfur compound can be any of those described in U.S. Patent 3,531,545; however, hydrogen sulfide is preferred. Its partial pressure is for example 0.01 to 10 bar (atmospheres).

The length of time for treatment with the sulfur compound is not critical, provided that it is in the desired amount Sulfur is brought to the catalyst. The usual period of time for this treatment catfish is between 5 minutes

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and 6 hours.

The second stage of the treatment of the catalyst by the process according to the invention is a treatment of the presulphurized catalyst with hydrogen, as above has been described.

Although the limiting conditions for these treatment catfish are not yet fully known, it appears that the best results are obtained when ^{operating above about 80 °} C., preferably at 110 ^° C. or above, e.g. from 80 to 250 ° C. or above, preferably from 120 to 160 ^° C. The contact time is usually 10 minutes to 10 hours. The hydrogen pressure is, for example, 0.1 to 10 bar (atmospheres) or above.

Preferred catfish are reported too strict or too long Treatment with hydrogen; Indeed, in the event of too reckless treatment, the catalyst takes one excess hydrogenation activity, which can damage the selectivity of the isomerization. In the following examples, the particularly favorable conditions when using these treatment catfish are specified.

The following examples illustrate the invention and in no way limit it. 70 988 1/092 β

Example 1; (Manufacture_of_Zatalxsator)

80 g of catalyst with 0.5% by weight of palladium on aluminum oxide are placed in a fixed bed at a temperature of 100 ° C. under a hydrogen atmosphere (ή bar pressure).

It is left at the same temperature and at the same pressure

Liter,

80 'of hydrogen containing 2 volumes of hydrogen sulfide flow over the catalyst for two hours. The temperature is then brought to 130 ^° C. and the hydrogen is allowed to flow under one bar (atmosphere) for 6 hours with a throughput of 40 ^ pvo hour. The catalyst is then ready for further use.

Example 2:

About 20 cm of the catalyst thus obtained is allowed to flow at the temperature of 80 ⁰ C under an overpressure of 25 bar (atm) of hydrogen with a mixture of 1-butene and 99.66 # 0.34 $ n-butane. The throughput of hydrocarbons (WH) is 5 volumes per volume of catalyst and per hour, the throughput of hydrogen is 1 liter per liter of catalyst per hour. A substance is obtained, the volumetric analysis of which is given below:

- 1-butene: 10,956;

- 2-butene: 87 #;

- n-butane: 2.1 #.

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Example 3:

Example 2 is repeated with the batch whose analysis is given in Table I. The temperature is 10O ⁰ C, the pressure 25 bar (atm), the VVH 10, 20 and 40 and the flow rate of hydrogen is 2.4 and 8 liters per liter of catalyst per hour; the results are given in Table I.

1, 40 I. , 40 Composition of
Product in weight per
cents WH = 40 12, 0 , 7 WH = 20 1.30 49, 47 VVH = OK , 93 1.40 13.90 Tabel 2, 68 1 ,8th 13.75 11.66 21 47 13th , 26 7.35 2.80 Composition of the batch
in percent by weight 12, 62 5 , 90 2.80 43.95 0, 36 2 5 ppm 46.8 26.40 Isobutane 48 27.90 <5 ppm n-butane 27 ^ 5 ppm Butene-1 < Isobutene Butene-2 trans Butene-2 ice Butadiene

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Example 4:

Example 2 is repeated with the batch rich in Isobutene and butadiene, the composition of which is given in Table II.

The pressure is 15 bar (atm), the temperature is 80 ^° C., the WH 10 and the throughput of hydrogen is 3 liters per liter of catalyst per hour.

Table II

Composition of Batch in Composition of the product Weight percent tes in percent by weight Isobutane 1.70 1.75 n-butane 9.25 11.19 Butene-1 25.7 2.50 Isobutene 47.1 47.00 Butene-2 trans 10.4 25.46 Butene-2 ice 5.3 12.10 Butadiene 0.55 <5 ppm

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Example; 5

A catalyst containing 0.5% by weight of palladium is used _; which is reduced to aluminum oxide. A charge, the composition of which is given in Table III and to which 100 parts by weight per million of hydrogen sulfide has been added, is passed over this catalyst, which is located in a bed of plague.

The conditions are as follows:

Temperature: 80 ⁰ C Pressure : 25th kg / cm WH: 5 Throughput
Hydrogen: 40 liter

: 40 liters per hour and per liter of catalyst

After 48 hours, the substance flowing out is analyzed and it is established that the isomerization is practically zero.

This example shows that the isomerization does not take place at 80 ^° C. in the presence of hydrogen sulfide.

Example 6; (YergleichsbeisOlel)

The experiment of Example 5 is carried out in the same way, except that the addition of hydrogen sulfide is omitted. η _Λ *. «.-.

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The leakage is analyzed after 48 hours. The analysis given in Table III shows that the degree of isomerization is low, which is due to the presence of the sulfur previously set (Example 5) by the catalyst.

Example 7:

Treating the catalyst obtained according to Example 6 with hydrogen at 135 ⁰ C under atmospheric pressure, wherein the flow rate of hydrogen hour is 400 liters / / Literlfatalysator.

After 6 hours of this treatment, the isomerization stage is carried out under the conditions of Example 6, ie at 80 ^° C., 25 kg / cm ² , WH = 5 and 40 liters of H ₂ / hour / liter catalyst (in the absence of hydrogen sulfide).

After 48 hours, the product is analyzed as indicated in Table III.

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Table III

Composition (weight ^) Starting batch Sulfurized catalyst
(Example 6) Desulphur
ter Kataly
sator (example
7) Isobutane 1.73 1.75 1.70 η-butane 9.93 11.16 11.15 Butene-1 54.05 39.02 4.85 Butene-2 trans22, i6 28.09 51.10 Butene-2 ice 12.0 19.89 31.20 Butadiene 0.13 0.09 <5 ppm

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Claims (11)

Claims M. j Process for the isomerization of 1-butene into 2-butene, characterized in that (a) that one has a sulfur compound with an isomerization catalyst brings into contact, which is a noble metal of group VIII of the periodic table of elements contains, (b) that the catalyst is then brought into contact with hydrogen and (c) that the catalyst obtained in step (b) with a hydrocarbon feed in the presence of Bringing hydrogen into contact, which contains 1-butene. 2. The method according to claim 1, characterized in that that the 1-butene is in the form of a hydrocarbon fraction which contains butadiene in addition to 1-butene. 3. The method according to claim 1 or 2, characterized in that the hydrocarbon charge is less than 5 ppm in Contains moles of sulfur or nitrogen. (ppm = parts per million) 4. The method according to any one of claims 1 to 3 »characterized in that the temperature is 50-HO is in the stage (c) ⁰ C. 709881/0928 Claims 5. The method according to any one of claims 1 to 4, characterized in that the isomerization catalyst Contains 0.01 to 2 weight ^ palladium on aluminum oxide 6. The method according to any one of claims 1 to 5, characterized in that the sulfur compound in one Amount used is at least 2 moles (gram atom) of sulfur per mole (gram atom) of the noble metal of the group VIII. 7. Method according to one of Claims 1 to 6, characterized in that step (a) is carried out at a temperature of 50 to 400 ^° C., using hydrogen sulfide which is diluted with hydrogen. 8. The method according to any one of claims 1 to 7, characterized in that step (b) is carried out at a temperature of at least 80 ^° C. 9. A method according to any one of claims 1 to 7, characterized in that step (b) is performed at a temperature of 110 to 25O ⁰ C. 709881/0928 Claims 10. The method according to any one of claims 1 to 9, characterized in that step (c) with a throughput, calculated in the liquid state, from 1-butene of at least 5 volumes per volume of catalyst and per hour is performed. 11. The method according to any one of claims 1 to 10, characterized in that step (c) is carried out with 1-butene, which is at least for the greater part in the liquid phase. 709881/0926