DE1518580A1 - Process for the mutual conversion of butenes - Google Patents

Description

PATENTANWÄLTE ^f

DIPL-CHEM. DR. WERNER KOCH DR.-iNG. RICHARD GLAWE

DlPLMNG. KLAUS DELFS

HAMBURG ■ MÖNCHEN

ΓΒτ.ΈχρΙ

L-- ————

2000 Hamburo-Großflotrbek Walzstrasse 12 Ruf 892255 8000 monks 22. Liebherrstrasse 20 ■ Call 226548

ρ ■ 3701 / 6-5 HAMBURG, the HAMBURG l / K

The British. Petroleum Company Limited, Britannic House Fins "bury-Circus," London, E.C. 2 / England

Process for the mutual conversion of butenes.

The invention relates to a process for the isomerization of oleic hydrocarbons and in particular to the mutual Conversion of lower monoolefinic hydrocarbons, such as Butene.

The term mutual conversion is intended to include both conversion of n-butenes to isobutene as well as the conversion of Include isobutene in n-butenes.

Although it is well known that fluorinated alumina catalysts various hydrocarbon conversions effect has now been 'surprisingly found that the used

90 9806/1082 _ ·, _.

fluorinated aluminum oxide catalysts meet certain conditions need to have a high degree of selectivity for mutual Conversion of butenes to obtain. It has been found that not all aluminas give satisfactory catalysts and that only those who have a certain reversible benzene adsorption, as defined later, are satisfactory Catalysts lead. It was also found that the weight percent Fluorine, which is retained on the specialized aluminum oxides, must be within certain limits if satisfactory Catalysts are to be obtained.

Accordingly, the present invention provides a process for the interconversion of butenes which consists in contacting the butene feed at an elevated temperature with a catalyst which is a fluorinated alumina with 0.5-1.5% by weight of fluorine includes, wherein the alumina is a reversible ijenzoladsorption - as defined below - measured at a benzene partial from o, 11 mm Hg and a temperature of 190 ⁰ C, of at least 2 nmol of benzene per gram of aluminum oxide has. The use of reversible benzene adsorption to assess the suitability of various aluminum oxides for use in the low temperature isomerization of C. and higher paraffinic hydrocarbons is described in the pending British patent application 42 830/62.

Reversible benzene adsorption is a measure of acidity, low values indicate low acidity. The measurement of the benzene adsorption of an aluminum oxide consists in that one Aluminum oxide with benzene vapors at a low partial pressure

and a fixed temperature and the

909806/1082

₂ ^ßAD ORIGINAL

measures adsorbed and desorbed steam amount. The amount of benzene adsorbed can change with the test conditions used and, in particular, with the partial pressure of the benzene vapor and the temperature. It is therefore necessary to standardize the conditions and for the purpose of the present invention the applied partial pressure is O ₁ H mm Hg and the temperature 190 ⁰ C.

A description of a suitable method for measuring the Bereol adsorption and a device for it are found in one Article by E. C. Pitkethly and A. G. Goble entitled "The Adsorption of Benzene on Supported platinum Catalysts ", published in" Actes du Deuxieme Congres International de Catalyse " Paris 1960, vol. 2, page 1851. The adsorption at low partial pressures is usually relative to chemosorption ascribing small contribution to physical adsorption and the apparatus for measuring it has three main parts, viz. (a) a device for introducing steam Cb-) a holder for the solid to be examined C-O-) a steam indicator

The device for introducing steam has a carrier gas source, e.g. for nitrogen or hydrogen, a container for the material to be adsorbed and a valve which allows that either the gas alone or gas containing very small amounts of the substance to be adsorbed is passed over the solid. The holder, which contains the catalyst or catalyst carrier, can be kept at a constant temperature over a wide temperature range. Gas that is passed over the catalytic converter, then goes through the sampling valve to the steam indicator, which can be a hydrogen flame ionization detector. The indicator

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system can have gas chromatographic columns if the rela- j tive rates of adsorption of various substances are determined should be or if a reaction under the test conditions is likely and the composition of the reaction product should be determined. It is not likely that this applies to the present invention.

By maneton gas flow, which the substance to be adsorbed contains, about the catalyst or the catalyst base that to be checked, directs and the difference between the amount of substance fed to the catalyst or the catalyst base and the amount that goes according to the indicator can measure the adsorbed Amount of substance after a small correction for the dead space can be determined in the system. If the flow of material then stopped and the gas alone is passed over the catalyst, the amount of substance that is desorbed can also be determined can. The amount desorbed here is known as the reversible adsorption; the difference between the adsorbed and desorbed Quantities is known as the irreversible adsorption.

The carrier gas for the Benaol vapors should be against aluminum oxide be inert and is preferably nitrogen.

The aluminum oxides to be tested are expediently given a standard pretreatment in order to bring them into a standardized chemical and physical state and in order to eliminate any effects which, for example, could be the result of different water levels. Prolonged heating in an inert atmosphere is preferred, for example 1 - 75 hours of heating between 100 and 8QO ⁰ C in dry nitrogen. a particularly preferred treatment is a 16 stundigeβ heating at 47o ° C in dry nitrogen <jngo ng / λ η ο j

. ■ ■ _ 4 _ ORIGINAL BATHROOM

Aluminum oxides suitable for use in the present invention have a reversible benzene adsorption of at least 2 μmol - "benzene per gram of aluminum oxide under the specified measurement conditions. Preferably, the reversible benzene adsorption is at least 3.5 μmol per gram. Fluorinated aluminum oxide catalysts based on aluminum oxides, which reversible benzene adsorption of less than 2 nmoles per gram have been found to be relatively inactive catalysts for the mutual conversion of butenes, ■

The catalysts used in the process according to the invention should have a fluorine content of 0.5 - 1.5 wt .- ^. Although catalysts containing less than 0.5 wt .- $ fluorine, are active to a certain extent, they have a very short lifespan, while those which are 'more than 1.5 wt .- ^ Contain fluorine, to hook proportions of cracked and polymeric Products lead to the disadvantage for the desired .butene isomers. The proportion of fluorine present in the catalyst is preferably 0.7-1.4% by weight. -

The catalysts used in the process according to the invention can be made in different ways. The aluminum oxide can be fluorinated by adding an inorganic fluoride, such as hydrogen fluoride, amnionium fluoride or ammonium hydrogen fluoride, or an organic fluorine compound such as those of the formula

Y ■ ■.

Y - i -? -. · ■

(where X is carbon or sulfur and each Y is fluorine or Is hydrogen) is used. The connections of the general

1082 ^ ₁₁ . _4I

BATH ORIGINAL

Formula are carbon tetrafluoride, fluoroform, methylene fluoride and the corresponding sulfur compounds. Carbon tetrafluoride was preferred. Carbon tetrafluoride is an extremely stable compound and prima facie is not an obvious choice for making fluorine-containing catalysts. Nevertheless, of course, it is suitable proven and has certain advantages over some other fluorine-. connections. For example, compared to hydrogen fluoride, it is non-corrosive, easier to handle, convenient to use To use vapor phase and less prone to damage the alumina. Compared with alkyl fluorides, which have a higher number Contain carbon atoms, e.g. tertiary butyl fluoride * it is less likely that carbonaceous or hydrocarbonaceous deposits will form on the catalysts during the Fluorination can be generated.

Preferably non-reducing conditions are used, when the aluminum oxide is brought into contact with an organic fluorine compound. A common method of touching consists in a stream of steam either alone or in a mixture with an inert gas, for example nitrogen, or im Mixture with an acidic gas, for example air j .oiber the aluminum oxide is passed.

If the above organic fluorine compounds are used for fluorination of the aluminum oxides, temperatures in the range 200-50O ⁰ C, in particular 500-55O ⁰ C • are generally used. In general, higher temperatures are used with shorter contact times, and vice versa. However, it has been found to be useful in preparing the catalysts for use in the present invention

90980 "Bf ΪΊ082

BATH ORIGINAL

Invention using the above organic fluorine compounds It is often difficult to determine the amount of fluorine absorbed by the oxide to control. So you can use catalytic converters with fluctuations Fluorine levels are obtained by adding aluminum oxide to organic Exposing fluorinating agents under identical fluorinating conditions. In order to prepare the catalysts in a reproducible manner, it is preferred that those in the copending British application 38 758/64, in which the aluminum oxide is first exposed to water vapor at room temperature is then partially dehydrated before adding the fluorinating agent is exposed. When using this method, catalysts with essentially deim & Lben fluorine content can be reproducible Way to be made.

However, it has been found that the problem of reproducibility practically does not exist when Smn using the alumina Ammonium fluoride fluorinated * Therefore the catalysts are used in the present invention, preferably by fluorination

made of aluminum oxide with ammonium fluoride.

The aluminum oxide is slurried with an aqueous solution of ammonium fluoride, the amount of ammonium fluoride used being calculated to give the required amount of fluorine, ie 0.5-1.5 wt. # In the finished catalyst. The slurry is then dried, oalciniert stiokstoffstrom during a period of for example about 3 hours, for example, at about 11Q ⁰ C, and * game, at 450 G in a ^0.

As mentioned above, the method according to the invention can can be applied both to the conversion of n-butene into isobutene and also to the conversion of isobutene into n-butene.

Therefore, the training for the process can be any butene isomer or contain a mixture of isomers, provided that the mixture does not correspond to the reaction conditions used Equilibrium mixture is.

The method-is carried out at elevated temperature ", and generally temperatures in the range 250 -. Applied 55O ⁰ G Pressures can ünteratmosphären- be atmospheric or super-atmospheric pressure and the GHSV of the feed may vary depending upon the temperature in the range of 100 to 10,000. Preferably, the starting olefin is fed to the reaction vessel in admixture with a diluent gas, for example an inert gas such as nitrogen.

The method according to the invention is explained in more detail by the following examples.
Example 1 - 8

Examples 1-8 show that it is necessary that the alumina base have a reversible benzene adsorption greater than
2 nmoles per gram. Examples 1-4 are exemplary embodiments according to the invention, while Examples 5 to 8 are only comparative examples.

There were 8 different aluminum oxides with different reversible benzene adsorption, measured at a benzene partial pressure of 0.11 mm Hg and 190 ⁰ C, after a pretreatment that ^{consisted of 16 hours of heating at 470 0} C in dry nitrogen, each fluorinated by the Alumina was slurried with an aqueous solution of ammonium fluoride, the amount of ammonium fluoride used being calculated to give the amount of fluorine required in the finished catalyst.

90980_6 _έ 1_082 _{BAD 0RIG1NAU}

The Aufschiämmungen were calcined at 110 C and dried in a nitrogen stream for 5 hours at 45O ⁰ G. Table 1 shows the reversible benzene adsorption values for each alumina along with the fluorine content of the catalysts. Any of these catalysts, it has been associated with one of two Butenbeschickungen into contact by the feed was / v / fed at a GHSV of 1000 v with nitrogen at a GHSV of 500 v v over the catalyst bed at 45O ⁰ C. Liquid products were caught in a trap at room temperature and after 1 hour of flow, the gaseous product on (a) butenes, (b) cracked and saturated by-products with carbon numbers less than or equal to 4 and (c) material with carbon numbers greater than 4 analyzed. . .

The one in table. % .compiled results show very

clearly that the aluminum oxides used in Example 1 - 4,

■ 2

which reversible benzene adsorptions of at least JiMoI pro Grams had satisfactory catalysts for each other Conversion of butenes provided. Examples 5-3 show that, although an appreciable degree of isomerization of Butene-2 is present in butene-1, only a very slight hint Isomerization to isobutene there.

9 0 9 8 O ^ ^ 1JO 8 2

1/908606

Table 1

at Alumi Bensol, adsor Wt .- ^ fluorine Loading cracked u. gaseous products after. Butene-1 Isobutene 1 hour weight # C. game nium
oxide beer at AIu-
minium oxide
basis
/ iMo l / g on the kata
lyser kung saturated Butene-2 14.5 33.6 Products> C, 1 A. 17.654 0.89 1 4.2 41.4 12.8 32.2 6.5 2 B. 9.09 0.94 2 8.0 38.4 16.4 29.8 8.6 3 C. 14,410 0.85 2 5.8 43.3 15.4 29 ", 6 4.7 4th Il 3,549 1.00 2 4.5 45.4 21.6 9.4 5.0 ι 5 E. 0.231 0.92 1 0.7 67.9 23.0 9.9 0.4 6th F. 1.074 0.92 1 1.0 65.1 24.8 3.2 1.1 ■ I. 7th G 1.649 0.93 1 0.9 70.7 25.1 4.8 0.4 8th H 0.122 1.00 1 1.0 67.8 1.2

Charge 1: butene-2, 98.4 wt%; Butene-1, 0.6 wt%; n-butane, 0.8 wt%; C ₅ , 0.2 wt .- ^
Feed 2; Butene-2, 93.2 wt .- ^; Butene-1,3.5 weight percent; n-utan, $ 2.5 wt; Butadiene, 0.2 Ge.-?

In each experiment, the fluid was flowed for an hour
less than 1 wt% of the feed.

Example 9-19

Examples 9 to 19 show that it is necessary for the use of the catalysts that they have a fluorine content in the range 0.5-1.5% by weight, preferably a fluorine content in the range 0.7-1.4% by weight .- #. Examples 9 and 16-19 are only comparative examples; Examples 10-15 are exemplary embodiments according to the invention. The catalysts used in Examples 9-17 were derived from the same alumina, only the percentage by weight of fluorine on the catalyst was varied. Each catalyst was treated with a butene feed, which 98.4 wt - $ butene-2, butene-1 0.6 fo, 0.8 $ η-butane and 0.2 $ C containing ₁ --Material, under the same conditions as indicated in Examples 1-8, and the products were analyzed after the times indicated in Table 2 below.

In Example 9 it can be seen that the percentage by weight Isobutene in the gaseous products has dropped considerably after only 98 minutes, a sign that the active life of the catalyst to effect the desired interconversion is small. It can be seen that as the weight percentage increases Fluorine on the catalyst the selectivity for isobutene formation is maintained over longer times, but with fluorine contents above about 1.5% by weight the formation of cracked and polymeric increases Products too, so that such catalysts are undesirable.

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909806/1082 ^BA °

Table 2

! V5 1

S801 / 908I Älumxni-
umoxyd 306 Time
(Min.) gaseous products wt .- ^ ge crack't +
saturated Butene-2 Butene-1 Isobutene Products rO. at
game A. Wt .- $
fluorine 5
98 7.0 * ^A
1.0 39.7
54.6 14.3
25.4 31.0
19.0 8.0
0 9 A. 0.43 5
, 60
150 2.4
2.1
2.8 43.6
54.7
54.1 15.2
19.1
20.2 30.3
21.1
19.6 7.9
3.0
3.3 10 A. 0.50 5
60
150 6.7
2.3
1.8 37.6
50.5
57.8 12.5
17.0
18.9 32.5
26.2
19.0 10.8
4.1
2.5 11 A. 0.62 5
60
120 10.9
3.3
2.9 36.4
44.6
47.2 12.0
14.8
15.6 31.8
31.2
29.4 9.0
6.2
5.0 12th A. 0.77 5
60
150 12.3
4.2
3.1 33.6
41.4
45.1 11.5
14.5
15.9 29.6
33.6
30.6 13.2
6.5
5.3 13th A. 1.00 5
iS8 17.1
8.3
7.2 30.1
36.5
38.0 10.2
12.0
12.1 26.1
31.5
32.1 15.6
11.6
10.6 H A. 1.33 60 13 _T 7 30.2 10.4 31.1 14.5 15th A. 1.50 5
90 19.3
10.2 29.5
35.5 10.4
12.9 24.6
31.0 16.2
10.4 16 A. 1.59 5
60
90 54.4
33.6 ■
24.6 18.0
22.6
24.3 4.3
7.3
8.1 10.6
18.1
19.4 12.7
18.3
23.6 17th E. 2.98 60 24.6 31.8 10.4 18.0 15.1 18th P. 5.20 60 31.1 25.2 8.1 17.7 17.9 19th 3.50

oo cn oo

λ I

Example 20

To the application of the process according to the invention to the conversion To illustrate from isobutene to n-butenes, a feed containing 0.6 wt. # of butene-2, 99.2 $ iaobutene and 0.1 $ Butadiene, via a fluorinated aluminum oxide catalyst, which was identical to that used in Example 13, conducted under the same reaction conditions. The products were analyzed after the set time and the results are shown in Table 3 below.

Table 3

at
game Alumini
umoxyd Weight #
fluorine Gaseous products after 1 hour weight% Butene-2 Butene-1 Isobutene Product
te> C. 20th A. 1.00 gecfaöSt
and sown
tigt ^ G ₄ 35.0 13.2 36.0 8.6 7.2

- 13 -909806/1082

Claims (8)

Claims 1. A process for the mutual conversion of butenes, characterized in that the butene charge "is brought into contact at elevated temperature with a catalyst which contains a fluorinated aluminum oxide with 0.5-1.5 wt .- # fluorine, the aluminum oxide being a has reversible benzene adsorption measured at a benzene partial from o, 11 mm Hg and a temperature of 190 ⁰ C, of at least 2 micromole of benzene per gram of alumina. 2. The method according to claim 1, characterized in that the proportion of fluorine present in the catalyst 0.7-1.4 wt .- # amounts to. 3. The method according to any one of the preceding claims, characterized characterized in that the fluorination of the aluminum oxide is effected by treating the aluminum oxide with ammonium fluoride, hydrogen fluoride or fluorinated ammonium hydrogen fluoride. 4. The method according to claim 1 and 2, characterized in that that the fluorination of the aluminum oxide is effected by reacting the aluminum oxide with an organic fluorine compound of the formula Y-X-F (where X is carbon or sulfur and Y is fluorine or hydrogen is) fluorinated. -H-909806/1082 bad original 5. The method according to claim 3 »characterized in that The catalyst is made by mixing the alumina with an aqueous solution of ammonium fluoride, hydrogen fluoride or ammonium hydrogen fluoride, whichever is used The amount of fluorine is calculated to give the required amount of fluorine in the finished catalyst, the resulting sludge is dried and calcining the dried product. 6. A method according to any of the preceding claims, characterized in that the elevated temperature in the range 250 - 55O ⁰ C is located. 7. The method according to any one of the preceding claims, characterized marked that the GHSV of loading in the area 100 - 10,000 v / v. 8. The method according to any one of the preceding claims, characterized in that the isomerization in the presence of a Diluent gas is effected. 909806/1082