DE1214666B - Process for the isomerization of mono-olefins - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C07c

German IQ .: 12o-i9 / oil

Number: 1 il4 666

File number: S 64653IV b / 12 ο

Anüi & ldeiagf 28; August 1959

Lay-out day: 2i. April 1966

The present invention relates to a method for the isomerization of Μθηο-olefineri, the A tertiary unsaturated carbon atom contains:

It is known that monoolefins can be isomerized with a wide variety of catalysts. B, sulfuric acid, phosphoric acid, aluminum chloride, etc. _} either in solution or applied to a solid adsorbent, is used.

In addition to isomerization, the strong Acids in olefins which contain a tertiary unsaturated carbon component, but also a be = Significant polymerization, thereby reducing the yield of the desired isomers.

In addition, these catalysts often cause major changes in the chain ", whereby likewise the yield of aii desired isomers is reduced;

Isomerization catalysts that have become known that are not strong acids, such as. B. activated Aluminum oxide, usually require high temperatures above 200 ° C, which is also reflected in lower yields of the desired isomers.

In the present invention, the acidic lies Reaction of the catalysts used in a range in which the formation of polymers is avoided will.

At the same time, chain changes are avoided in the method of the invention;

Further advantages of the present invention consist in carrying out the isomerization of Mono-olefin compounds having an unsaturated tertiary carbon atom in the liquid phase and Mi lower temperatures compared to previously known processes.

It is aubh already proposed a method of branched or Hefstellung more branched alkenes of unbranched or slightly branched alkenes become known, in which the alkenes or the alkene-containing mixtures at temperatures of about 275-500 ⁰ C and the hydrated alkali AluminiuniiSüikateh the type of Pernlutits or zeolites treated. Sb is used, for example, n-butenes and η-butane, granulated sodium permutite is added and the process is carried out at atmospheric pressure under a temperature of 450 ^° C. for a contact time of 183 seconds. This gives 33% total methyl-2'propene. This known process works at very high temperatures of about 275 to 500 ⁰ C, which has the consequence that in addition to the isomerization reaction, other processes for isomerization of
Mono-olefins

Applicant:

ίο Halcon International, Inc.,
New York, NY (V. St. A.)

Representative:

Dipl.-Chem. Dr. phil. E. Storm; Patent attorney ^
Munich 23, Leöpoldstr. 2Ö

Named as inventor:
Charles N. Winhick, Great Neck, NY (V. St-. A :)

Claimed priority:
V. St. v. America from 2. October 1958
(764759)

Implementations take place and in particular the

Risk of polymerization reactions is great, reducing the yield of isomerized products suffers.

Another process for the isomerization of open-chain olefin hydrocarbons works in such a way

that an open-chain olefin in a period of 10 to 2-50 seconds in the vapor phase at Tempe- • temperatures between 275 and 500 ° C with a hydrated Aluminum silicate is treated. The silicates used have basic exchange properties

up, which causes isomerization will. According to a particular embodiment of this process, artificially produced one is used hydrated aluminum silicate which belongs to the class of permutites or zeolites. Even In this known process, it has disadvantages that one in the vapor phase at high temperatures have to work. The disadvantages are that not only one isomerization reaction takes place, but that at the same time the polymerization to un-

desired by-products takes place.

The object of the present invention is therefore to provide a process for isomerization of mono-

609 559/418

to create olefins in which such favorable reaction conditions be used that only an isomerization of the olefin components takes place and that, on the other hand, the polymerization reaction is suppressed to a great extent.

The object is achieved in such a way that in a process for isomerizing monoolefins by shifting the double bond with the aid of a zeolite catalyst, according to the invention, the isomerization with a mono-olefin which contains the double bond to a tertiary carbon atom is carried out in the liquid phase at a temperature of about 30 to 100 ⁰ C, preferably 40 to 80 ⁰ C, carried out in the presence of a zeolite catalyst, which by treatment with an aqueous alkaline solution, then washing until the washing water reacts neutral, subsequent treatment with a buffered acidic solution with a pH in the range from 2.5 to 6.0, repeated washing until the washing water reacts neutral and then drying.
- According to a preferred embodiment of the invention, the isomerization is carried out with a mono-olefin having 5 to 14 carbon atoms.

In many processes _# for further processing of olefins a mixture of hydrocarbons, is used as a starting material in which the desired isomers are present only in relatively small amount.

According to the method of the invention, in such mixtures, which mono-olefins with an unsaturated tertiary carbon atom containing the. desired isomer content can be increased. Through this these processes become more economical and higher yields per unit of space supplied are obtained of the mixture, and the problems of separation and purification are simplified.

The term "zeolite" used in this specification is intended to be both natural and synthetic acidic materials, particularly clays exhibiting ion exchange properties.

The invention is to be explained in more detail by the following preferred embodiments.

example 1

A granulated catalyst is selected from silicon oxide-aluminum oxide-zeolite is treated with a .10 ° / ₀ sodium carbonate solution and then thoroughly washed with water until the wash water reacted neutral. The catalyst is then treated with a buffered with sodium acetate to pH 4.6 acetic acid, washed until the wash water is neutral, and then dried with dry nitrogen at a temperature of approximately 100 ⁰ C.

The catalyst obtained in this way, the preparation of which is not the subject of the present invention, is introduced into a reaction vessel and heated to a temperature of approximately 60 ° C. with an equal volume of 2-methylpentene-1 for 20 minutes. This gives an equilibrium mixture of approximately 85 parts of 2-methylpentene-2 and 15 parts of 2-methylpentene-1. There are about 3 ° / ₀ formed of polymerized material.

If the pretreatment of the zeolite catalyst has not been carried out in the manner indicated, takes place in considerable amount of undesirable polymerization. This is explained by the following two experiments:

A silica-alumina zeolite catalyst is treated in the same manner as described above, with the difference that the neutralization step (treatment with sodium carbonate) is omitted. 2-methylpentene-l is heated for about 20 minutes with this non-neutralized catalyst to a temperature of 6O ⁰ C. The final product thus obtained contains a substantial amount of polymerized material, namely approximately 55 ° / _0th

A zeolite catalyst made of silicon oxide-aluminum oxide, which has not been pretreated with either an alkaline or an acidic solution, is ^{dried at 100 °} C. for 3 hours. Then 2-methylpentene-1 is brought into contact with this catalyst for the temperatures and times indicated below. The mixtures of C ₆ olefins and amounts of polymerized material given below are obtained:

Time
Minutes Tempe
rature
⁰ C ratio of
2-methylpentene-2
to 2-methylpentene-1 Weight percent
at Polymeiem 2
5 60
19th 82:18
32:68 41
14th

This experiment also shows that even with short reaction times, a substantial formation of polymers occurs when an untreated silica-aluminum oxide zeolite catalyst is used will.

Example 2

The procedure of Example 1 is repeated with the difference that the treatment with that with Sodium acetate buffered acetic acid at the pH values given below.

The 2-methylpentene-l is heated with these catalysts for the time specified below to approximately 6O ⁰ C, and C will receive _e-olefins of the composition indicated below. At the same time, the specified amounts of polymer were obtained.

• 7 «: + 2-methylpentene-2- Weight pH 2-methylpentene-l- percent on Minutes relationship Polymer 4.1 5 63:37 5.0 4.1 10 79:21 7.5 4.9 5 43:57 2.0 4.9 10 62:38 2.5 4.9 20th 78:22 3.0

Example 2 shows that polymer formation can be reduced when treated with sodium acetate-acetic acid is carried out in a pH range of about 4 to 5 with increasing pH.

This isomerization can also be carried out continuously by 2-methylpentene-l is passed over the catalyst layer, with an hourly space velocity of 3 at a temperature of about 6O ⁰ C and substantially at atmospheric pressure, wherein an in cocurrent

Claims (1)

5 6 weight-bearing mixture of 2-methylpentene-2 and delter catalyst is more active, and therefore 2-methylpentene-1, as described above, get rend the isomerization a larger amount of poly- will. The space velocity can be established in the wide merized material. Therefore, at Range from 1 to 10, and it is desirable to lower the pH of the buffer solution with Range from about 2 to about 4. The temperature at which the catalyst is treated, namely the the temperature of the reaction rate penetrating the catalyst layer is increased, but the same 2-methylpentene-1 is approximately between 35 ° C and too early the amount of undesired polymeric the boiling point of the organic phase is increased in the case of the anized material. applied partial pressure. Desired results will be an isomerization of mono-olefins produced by Containing 5 to 14 carbon atoms in the temperature range of about 45 to 7O ^{0 C io is particularly} while maintaining a required moderately desirable to produce isomers which at a th pressure in the system. Cracking yields valuable end products, however advised that the present invention Example 3 should include all processes in which from mono- 15 olefins, the unsaturated tertiary carbon atoms It will contain approximately 6 parts by weight of 2,3-dimethyl, isomers can be formed. butene-2 with a part of a treated according to Example 1, although in the previous examples the th silicon oxide-aluminum oxide catalyst using treated with sodium carbonate solution mixes. The mixture is described on a fractionated catalytic converter. column heated under reflux. The 2,3-dimethyl 20 indicated that any other base, such as. B. Sodium 1-butene, which boils at 55.5 to 56.5 ° C, distilled all-umhydroxyd, which neutralize the catalyst gradually from. There is a 95 ° / _o yield this can, when not claimed herein Preparation Isomers obtained. Essentially no poly catalyst can be used. The con- merized material formed. concentration of the alkaline solution can be between 2 to 25 20 weight percent, preferably 5 to 15 ° / ₀ and Example 4 is desirably 10%. Used as the acid medium for the buffer solution Approximately 6 parts by weight of 2-methyl-acetic acid are mentioned, but the catalyst can also butene-1 in a soxhlet set up for pressure with any other buffered acidic medium apparatus over a part according to Example 1 treated 30 _e in _a pH range of 2.5 to 6.0, preferably 3.5 to Silica-alumina catalyst under 5.5 _and desirably 4 to 5 have been prepared river boiled. The pressure in the system is based on such _se in. Height held that the liquid boils at 70 ⁰ C. I _n the foregoing examples the check was After 8 hours, 96% of mixed methyl turn a nitrogen-dried catalyst butenes obtained from 81 ° / ₀ 2-methylbutene-2 and 35 _sators recommended, but the catalyst can with 19 ° / ₀ 2-methylbutene-l exist. It is essentially the aid of any suitable drying process, borrowed no polymerized material obtained. in particular drying with an inert gas stream at 60 to 150 ° C, with embroidery Example 5 material of 100 ° C is given preference, produced 40 turned out to be. There are approximately 9 parts by weight of a carbon. It should be noted again that the isomeric hydrogen mixture, consisting of 70% 2-ethylization in the liquid phase at temperatures in the butene-1, 20% 3-methylpentene-2 and 10% other range of about 30 to 10Ό ° C is carried out, olefins, mainly η-hexene, in a Soxhlet ± h. in lower boiling olefins, to the Siedeapparat, of 1 part treated according to Example 1 Silici- _{45 pun} the organic phase at the particular anumoxyd-alumina catalyst contains kt, 18 STUN facing partial pressure can be used. When the refluxed. The resulting end-the olefins are high-boiling substances cannot be worked product contains 84% 3-methylpentene-2 and 5% more at the boiling point, since the tem-2-ethylbutene-1. Essentially no polymerized material was formed during the isomerization, which was kept below 100 ° C. ₅ o must be in order to prevent the formation of undesired secondary From the above it can be seen that products should be avoided. Desired results will be that the present invention allows for those in the temperature range of about 40 to 80 ° C Hand there, through a conversion of not im received. Equilibrium mixtures of olefins in the _p . ..,
Equilibrium mixtures of olefins to 55 respiratory demands.
achieve. If one starts from the equilibrium 1st process for isomerizing mono-mixtures, then by removing the gel olefinic isomer desired by shifting the double bond and using the present invention with a zeolite catalyst to achieve renewed equilibrium, that the isomerization weight conditions the average yield of 60 tion with a mono-olefin which enhances the doubles of the desired isomer. bond to a tertiary carbon atom Assuming that it is not in equilibrium, it is in the liquid phase at one temperature Mixtures of, so you can choose from about 30 to 100 ° C, preferably 40 to 80 ° C, carries out the starting materials both from one and from in the presence of a zeolite catalyst, the opposite side of the equilibrium from that obtained by treatment with an aqueous alkaline solution go as the reactions are reversible. Solution, then washing until neutral It should also be noted that a subsequent treatment when the washing water is low rem pH with a buffered solution treated with a buffered acidic solution with a pH-value in the range from 2.5 to 6, Ö, necessary Morio-Ölefiil with 5 to 14 RöhtemtöfMomen Washes are carried out until the wash has a neutral reaction; _ water and then made TrÖe'kneü ~ has been. Iu considered 'publications: 2. Ancestors according to claim i, characterized in that 5 British Patent No. 501 8 ^ 8 = indicates that the isomerization with a ÜSÄ. Patent No. 2 217 2S2. 609 559/418 4.66 © Bundesdruckerei Berlin