The invention relates to a method for producing an alpha-olefin and a corresponding plant according to the preambles of the independent claims.

State of the art

The production of alpha-olefins (α-olefins) by oligomerization of ethylene is known and is described in the specialist literature, for example in D. Steinborn, Fundamentals of Organometallic Catalysis, Wiley-VCH, 2012, in particular Chapter 8, "Oligomerization of Olefins" . Important process variants are, for example, the Shell Higher Olefin Process (SHOP) and the Alpha-SABLIN process, as explained by Steinborn in subsections 8.4.1 and 8.4.2 and elsewhere.

In the processes mentioned, mixtures of even-numbered alpha-olefins are formed in a typical Schulz-Flory distribution, with the focus

typically lies on the formation of 1-butene and 1-hexene.

From EP 3 338 884 A1 a process for the oligomerization of ethylene to alpha-olefins is known, comprising an ethylene oligomerization step, a

Catalyst deactivation step and a product separation step, the reactor being provided with a cooling circuit, by means of which at least part of the reaction effluent is circulated through at least two exchangeable heat exchangers, the heat exchangers alternating through an integrated one

Cleaning device to be cleaned.

The object described in JP H07-149672 A is to provide a process for the production of 1-hexene on an industrial scale at low cost by the oligomerization of ethylene, followed by the separation of 1-hexene from the reaction solvent by distillation and recycling of the

Specify reaction solvent in the reaction system. As a solution, it is proposed to use 1-hexening by oligomerizing ethylene in one

To produce reaction solvents so that an alpha-olefin oligomer

A composition is obtained which contains at least 50% by weight of 1-hexene. The 1-hexene and the reaction solvent are separated off from the

Reaction liquid containing the reaction solvent and the alpha-olefin oligomer composition by distillation and recycling of the

recovered reaction solvent to the reaction system.

According to US Pat. No. 3,424,810 A, a mixture containing normal alpha-olefins and vinylidenes is treated with the acid form of a sulfonic acid cation exchange resin which has a macroreticular structure to form a resulting

Composition with larger amounts of normal alpha-olefin and less vinylidenes. The resulting composition is said to be useful to aromatic compounds in the production of biodegradable ones

Alkylating detergents.

In US Pat. No. 3,367,987 A, a process was protected in which a mixture consisting essentially of hydrocarbons and predominantly containing at least one normal alpha-olefin with 6 to 8 carbon atoms and smaller amounts of at least one vinylidene at a temperature between about -50 ° C. and about 100.degree. C. with a Friedel-Crafts catalyst selected from the group consisting of iron (III) chloride, boron triluoride and boron triluoride etherate, in order to polymerize the vinylidene selectively .

According to US 4,51 1,753 A vinylidenes are selectively removed from an olefin mixture by the mixture with either hydrogen sulfide or a

Hydrocarbyl mercaptan is reacted and then the resulting mixture is distilled to obtain a substantially vinylidene-free product.

Medium chain olefins which contain 2-alkyl-substituted isomers with a near boiling point as impurities are purified according to EP 0 648 721 A1 by (i) passing them under mild conditions over a solid acid catalyst in order to selectively remove the impurities To isomerize double bond, and (ii) the isomerized olefins are separated by distillation.

The oligomerization processes mentioned at the beginning and in particular the Alpha-SABLIN process are extremely flexible in terms of product distribution. So can

Distributions with yields of, for example, 30 to 40 percent by weight of 1-butene and 1-hexene can be set. In this case, the fractions formed in each case usually meet the product quality requirements of the market

Foreign connections.

When setting higher yields of, for example, 40 to 70 percent by weight of 1-butene and 1-hexene, however, the market requirements for the fractions are no longer met due to an increased production of branched olefins in the individual fractions. Correspondingly high yields are nevertheless desirable. Therefore, in such cases, a so-called

Superfractionation of the 1-butene, the 1-hexene, the 1-octene and / or the 1-decene fraction and a separation of branched olefins take place.

For example, in the cases mentioned, the 1-hexene fraction can be contaminated with 0.5 to 2 percent by weight of the somewhat higher-boiling component 2-ethyl-1-butene, depending on the distribution set.

The 1-octene and 1-decene fractions are typically each contaminated by lower-boiling components which, however, boil very close to the respective alpha-olefins, namely by 2-ethyl-1-hexene and 2-ethyl-1-octene .

Against this background, the present invention is in particular the

The task of creating improved possibilities for the production of pure or specification-compliant alpha-olefin fractions.

Disclosure of the invention

Against this background, a method for producing one of alpha olefins and a corresponding plant are proposed according to the preambles of the independent claims. Refinements are the subject of the dependent claims and the following description.

Before explaining the features according to the invention, further principles of the invention are explained and terms used are defined.

In general, “primary fractionation” of a mixture of alpha-olefins is understood here to mean the formation of a component mixture which contains a linear alpha-olefin of a certain carbon number, but is low in or free of linear alpha-olefins of other carbon numbers. Such a component mixture is also referred to below as the “primary fraction” of a corresponding linear alpha-olefin, for example as a 1-butene, 1-hexene, 1-octene or 1-decene primary fraction. The characteristic linear alpha-olefin, since it is present in the predominant proportion, is hereinafter also referred to as the "main component" in a corresponding primary fraction.

A corresponding primary fraction can in addition to the respective

Main component have lower-boiling and / or higher-boiling components. This is the case in the method proposed according to the invention. According to the definition, however, these are not other linear alpha-olefins but, for example, branched olefins, paraffins or linear olefins with a non-terminal double bond. These each have a boiling point which is at a distance from a boiling point of the main component, this distance being less than a distance between the boiling point of the main component and a linear alpha-olefin that is two carbons more or less than that

Has main component.

The mentioned lighter and / or higher boiling components are separated off in a so-called super fractionation, hereinafter also referred to as "secondary fractionation". The fractions formed in the secondary fractionation, which are also referred to below as "secondary fractions", are thus depleted in the lower and / or higher boiling components compared to the corresponding primary fractions, but typically not completely free of these for technical reasons. In a 1-hexene secondary fraction, typically no more than 0.5 percent by weight, in a 1-octene secondary fraction typically no more than 3 percent by weight and in a 1-decene secondary fraction typically no more than 3.5 to 4 percent by weight of the heavier weight contain boiling components.

The super fractionation results in additional losses as well as increased operating costs and increased investment costs. This is all the more true the closer the

Boiling points of these lighter and / or heavier components are close to those of the respective main component, since this makes separation more difficult. The 1-hexene fraction is particularly affected because in this the very near-boiling component 2-ethyl-1-butene corresponds to or exceeds the residual levels to be set.

Advantages of the invention

From RU 2 206 557 C1 a process is known in which 2-ethyl-1-butene is reacted in a component mixture with 1-hexene by selective isomerization of to 3-methyl-2-pentene over a catalyst. The catalyst is a macroporous sulfocationite with a volume-related capacity of 3.5 to 4.5 mg c equ. H7g. The process is carried out at a bed speed of 1 to 10 h 1 and at a temperature of 40 to 80 ° C. The content of 2-ethyl-1-butene in the component mixture is more than 1% by weight, with 4.3% by weight being mentioned in a specific example. The 1-hexene content is more than 95% by weight. The 2-ethyl-1-butene contained is converted to 86 to 97%, whereby

Conversion losses of 1 to 2.6% of 1 hexes result.

While under the relevant conditions here 1-hexene has a boiling point of 63 to 64 ° C and 2-ethyl-1-butene has a boiling point of 64 to 65 ° C, and these components can therefore only be separated from one another with great effort or not at all, cis / trans-3-methyl-2-pentene has a boiling point of 67 to 72 Ό and is therefore much easier to separate. A corresponding intermediate step therefore makes the super fractionation or secondary fractionation significantly easier.

According to the invention it has now surprisingly been recognized that such a

Intermediate step can also be carried out with a significantly lower conversion of 1-hexene or another alpha-olefin. In this way, a process can be created in which product losses are significantly reduced. The undesired conversion of 1-hexene is a side reaction in which cis / trans-2-hexene and / or cis / trans-3-hexene are formed.

Measures to reduce the undesired conversion include in the context of the present invention the use of a reaction moderator, namely water, while in an embodiment not according to the invention the use of a less acidic catalyst is also considered, as explained below.

Overall, the invention proposes a process for the production of linear alpha-olefins, in which ethylene in a feed mixture to obtain a

Product mixture, the alpha-olefins with different chain lengths and

Contains secondary compounds, is subjected to a catalytic oligomerization.

In the context of the present invention, basically all

Processes for the catalytic oligomerization of ethylene are used, which are known from the prior art. Reference is therefore made to the above explanations. In particular, the catalytic oligomerization can take place in the form of the known SABLIN process, as also explained at the beginning. The catalytic oligomerization can in particular be carried out with a yield of 40 to 70 percent by weight of 1-butene and 1-hexene.

In the context of the invention, in particular 1-butene, 1-hexene, 1-octene and / or 1-decene can be formed as linear alpha-olefins. The secondary compounds can in particular be 2-ethyl-1-butene and 2-ethyl-1-hexene or

more generally about 2-ethyl-1-olefins with the same carbon number as the respective linear alpha-olefins which are formed as target products. Further secondary compounds possibly formed in the course of a corresponding process include cis / trans-3-hexene, n-hexane, cis / trans-2-hexene, cis / trans-3-octene, cis / trans-4-octene, trans-2- Octene, n-octane and cis-2-octene. The secondary compounds are not linear alpha-olefins.

In a primary fractionation, within the scope of the present invention, a primary fraction is formed using at least part of the product mixture from the catalytic oligomerization, and in a secondary fractionation a secondary fraction is formed using at least part of the primary fraction. The terms of the primary fraction and the secondary fraction or

corresponding fractionation steps are referred to the explanations above.

The secondary fractionation can in particular be carried out in the form of a known super fractionation. Primary and secondary fractionation can take place in particular in the form of thermal separation steps, in particular in the form of

Rectifications.

According to a particularly preferred embodiment of the present invention, the primary fraction can be dried before it goes to the secondary fractionation

is subjected. All known methods can be used for drying, for example adsorptive drying using suitable adsorption materials. Since, in the context of the present invention, a certain water content is used in the subsequent process step, because water is used as a reaction moderator, drying can also only take place downstream of this process step or can be omitted entirely.

In the context of the present invention, the primary fractionation and the secondary fractionation are carried out in such a way that the primary fraction and the

Secondary fraction predominantly contain one of the linear alpha-olefins and are poor in or free of other alpha-olefins, that the primary fraction contains one or more of the secondary compounds, and that the secondary fraction is depleted in one or more secondary compounds compared to the primary fraction or (if technically sensible and possible) is free of this. In other words, it is ensured in each case that the primary fraction, in addition to the respective main component in the form of the linear alpha-olefin, preferably does not contain any further linear alpha-olefins or that these are only contained to a very small extent.

If it is said here that “a” primary fraction is formed, this of course does not exclude the formation of further primary fractions with corresponding other linear alpha-olefins as the main component. For example, a 1-hexene primary fraction, a 1-octene primary fraction, a 1-decene primary fraction and / or a 1 -dodecene primary fraction can be formed as primary fractions, each of which contains corresponding secondary compounds.

According to the invention, in an intermediate step between the primary fractionation and the secondary fractionation, to which at least part of the primary fraction is subjected, the one or more secondary compounds are at least partially converted into one or more subsequent compounds, and the one or more subsequent compounds are then converted into the Secondary fractionation separated at least in part.

As a secondary compound in a 1 -Flexen primary fraction, as explained,

in particular 2-ethyl-1-butene, which, as mentioned, differs only slightly from 1-Flexen in its boiling point. As a result of the reaction in the intermediate step, cis / trans-3-methyl-2-pentene can be formed from this, which, with its higher boiling point, can be separated off much more easily.

In a 1-octene primary fraction, for example, 2-ethyl-1 -flexene can be used as

There are secondary connections. The boiling point of 1-octene is 121 O, that of 2-ethyl-1-flexene is 120 G. By converting 2-ethyl-1-flexene to cis / trans-3-methyl-2-flepten with a boiling point from 122 to 126 G, the separation of this secondary compound is also facilitated. Because this secondary compound is shifted to the boiling point of other octene isomers as a result of the reaction mentioned, it can be separated off together with these. So 2-octene and 3-octene also boil above 122G. The same applies to other secondary connections in the same or a comparable manner.

The invention is now characterized in that the intermediate step is carried out in such a way that no more than 0.8%, in particular no more than 0.5% or 0.2% based on weight, volume or molar basis of the alpha-olefin , which is predominantly contained in the primary fraction or in the part thereof that is subjected to the intermediate step, are converted.

In particular, within the scope of the present invention, the one or more secondary compounds can be converted in the intermediate step down to a residual content of at most 0.4%, in particular of at most 0.2% or 0.1% on a weight, mol or volume basis will. This residual content can relate, for example, to a 2-ethyl-1-olefin with the same carbon number as the linear alpha-olefin predominantly contained in the primary and secondary fractions and denotes in particular the content in the primary fraction after the reaction in the intermediate step. The conversion of the 2-ethyl-1-olefin in the intermediate step can in particular give a cis / trans-3-methyl-2-olefin with again the same

Carbon number.

In other words, in the context of the present invention, the reaction of the 2-ethyl olefin with the same advantageously takes place as completely as possible

Carbon number, depending on the fraction of 2-ethyl-1-butene, 2-ethyl-1-hexene or ethyl-1-octene. The conversion takes place in particular to a residual content in the range already indicated above.

As mentioned, measures to reduce the undesired conversion of the respective linear alpha-olefin can in particular include the use of a reaction moderator, for example water, and / or the use of a less acidic catalyst, as explained below.

In the context of the process according to the invention, the intermediate step in

Presence of water carried out as a reaction moderator. This applies in particular to a 1-hex primary fraction. In the context of the present invention, the water is used in a content of 20 to 200 ppm by weight, in particular of 30 ppm by weight to 150 ppm by weight, of 60 ppm by weight to 130 ppm by weight or of 50 ppm by weight .-ppm to 100 wt. ppm, used. Water can already be contained in the product mixture subjected to the primary fractionation or it can be added separately. It is present in particular in the reaction insert subjected to catalysis. Through the use of water as a reaction moderator, the present invention has the particular advantage that the acid strength of the catalyst can be reduced in a targeted manner, so that the undesired isomerizations of the alpha olefin can thereby be greatly reduced.

The process is carried out according to the invention using a strongly acidic ion exchange resin in the intermediate step. A macroporous sulfocationite, for example a commercially available macroporous sulfocationite, can in particular be used as the strongly acidic ion exchange resin.

In the first embodiment of the present invention, the strongly acidic ion exchange resin can in particular have a volume-related capacity of

have at least 4 eq / kg, and / or the intermediate step here can be carried out at a bed speed of 5 to 40 h 1 at temperatures of 30 to 60 °, in particular from 40 to 50 °. Under these reaction conditions, the advantages result from the inventive use of the

Reaction moderator water can be achieved in a special way.

In the present invention, there is a moderate conversion of in particular only 0.1 to 0.5 or 0.8% of the alpha-olefin predominantly contained in the primary fraction or its part subjected to the intermediate step with conversions of the secondary compound to be isomized from 85 to 95% . The process according to the present invention therefore increases the yield considerably over the prior art.

In an embodiment not according to the invention, the intermediate step could also be carried out using an aluminum oxide-based catalyst which in particular has chi- and gamma-dialuminum trioxide. In this

Embodiment, the acid strength is already in a range in which no moderator is required and thus a low conversion of the alpha-olefin compared to that of the 2-ethyl-1-olefin is achieved.

In this embodiment of the present invention, which is not according to the invention, the aluminum oxide-based catalyst can in particular have a surface area of ​​450 to 460 m 2 / g, and the intermediate step here can be carried out using a bed speed of 1 to 12 h 1 . Under these

Reaction conditions, the advantages of this embodiment not according to the invention result in a special way.

In the embodiment just explained, which is not according to the invention, there is a particularly low conversion of in particular less than 0.1% of the alpha-olefin predominantly contained in the primary fraction or its part subjected to the intermediate step with a conversion of the secondary compound to be isomized by 85 to 95% and thus also an improved increase in yield.

In the context of the present invention, but also in the mentioned embodiment not according to the invention with a catalyst with a lower acid strength, it has proven to be particularly advantageous to carry out the intermediate step in one

Carry out temperature level of 60 to 100 O, in particular from 70 to 90 O, and at a pressure level of 1.0 to 4.0 bar absolute pressure. In all

Embodiments of the present invention and in the embodiment not according to the invention can also be used to regenerate the catalyst used, for example, several reactors in the

Alternating operation can be used, of which at least one is available for the intermediate step.

The present invention develops particular advantages in all cases if the product mixture contains 1-hexene and / or 1-octene in a content of more than 50, 60, 70, 80 or 90% by weight as the main component (s).

Advantageously, the alpha-olefin, the primary fraction and the

Mainly contain secondary fraction, being 1 -hexen, the content of 1 -hexen being more than 90% by weight. The secondary connection or one of the

Secondary compounds in such a case is in particular 2-ethyl-1-butene and / or the subsequent compound or one of the subsequent compounds is in particular 3-methyl-2-pentene in such a case.

However, the invention can also be used with particular advantage if the alpha-olefin which the primary fraction and the secondary fraction predominantly contain is 1-octene, the 1-octene content being more than 90% by weight. In such a case, the branch connection is or one of the branch connections

in particular 2-ethyl-1-hexene and / or the subsequent compound or one of the

In such a case, subsequent compounds are in particular 3-methyl-1-heptene.

The advantages of the configurations explained, which include the fact that the implementation achieves a greater boiling point difference and thus a simplified separation, have already been explained in detail above.

Examples

The method (“reference”) disclosed in the aforementioned RU 2 206 557 C1 was compared with three examples (“example 1” to “example 3”). The results of this comparison and the catalysts used in each case, others

The reaction conditions are summarized in Table 1.

In the reference and in examples 1 and 2, a macroporous sulfocationite was used as a catalyst, with examples 1 and 2, as in the reference, each using a commercially available product. Examples 1 and 2 differ from one another essentially in the amount of as

Reaction moderator used water, so that with Example 2, the advantages of an embodiment of the present invention can be demonstrated.

In contrast, in Example 3, an amorphous chi and gamma dialuminum trioxide was used as the catalyst, a commercially available product also being used. As in Example 1, however, a very small amount of water was used. Example 3 thus demonstrates, merely for comparison with Examples 1 and 2, the features of the embodiment not according to the invention mentioned several times.

Table 1

Conversion of 2-ethyl-1-butene 86 to 97%
85 to 95%

As can be seen from the comparison of the results, in Example 1, in which a comparable catalyst as in the reference and a small amount of water were used as the reaction moderator, no noteworthy improvements with regard to the conversion of 1-hexen compared to the reference can be achieved.

However, significant improvements occur when using higher amounts of water according to Example 2, ie in the embodiment of the present invention, and when using the chi- and gamma-dialuminum trioxide as a catalyst according to Example 3, ie in the embodiment not according to the invention.

In a further example ("Example 4") an amorphous chi and

Gamma-dialuminum trioxide used as a catalyst, a commercially available product was also used. The features of an embodiment not according to the invention are therefore also shown here.

It was shown that the deactivation of the catalyst is caused by the water content in the reaction insert and is also reversible. Using common methods of regeneration, the isomerization property can be completely reduced to the

Initial activity will be restored. The frequency of regeneration can be avoided and / or reduced by adding a pre-dryer. Example 4 was carried out at a bed speed of 12 h 1 at a temperature of 90 °, a pressure of 4 bar above atmospheric pressure, with 3.8 g of catalyst and with a moisture content of 40 ppm by weight in the reaction. The pre-dryer was operated with 7 g of Selexsorb CDX at approx. The results are summarized in Table 2. In this table, columns 2 and 3 show the content of 2-ethyl-1-butene and 1-hexene in the reaction feed.

Table 2

In a further example ("Example 5") an amorphous chi and

Gamma-dialuminum trioxide used as a catalyst, a commercially available product was also used. Here, too, the features of an embodiment not according to the invention are shown. It has been shown that the losses of 1-hexes can be minimized via the bed speed. A temperature of 90 O, a pressure of 4 bar above the

Atmospheric pressure and 3.8 g of catalyst used. The humidity in

Reaction use was less than 20 ppm by weight). The results are in

Table 3 below.

Table 3

drawings

In FIG. 1, a method for the production of linear alpha-olefins according to an embodiment of the invention is shown in the form of a schematic flow chart and designated as a whole by 100.

In the process 100, ethylene is in a feed mixture A to obtain a product mixture B, the alpha-olefins with different chain lengths and

Contains secondary compounds, subjected to a catalytic oligomerization 1.

In a primary fractionation 2, using at least part of the product mixture B, a primary fraction C is formed, and in a secondary fractionation 4, using at least a part of the primary fraction C is formed

Secondary fraction formed.

The primary fractionation 2 and the secondary fractionation 4 are thus

carried out that the primary fraction and the secondary fraction contain predominantly one of the alpha-olefins and are poor in or free of other alpha-olefins, that the primary fraction contains one or more of the secondary compounds, and that the secondary fraction compared to the primary fraction at one or the other several secondary compounds is depleted.

In an intermediate step 3 between the primary fractionation 2 and the

Secondary fractionation 4, to which at least part of the primary fraction C

is subjected, the one or more secondary compounds are converted at least in part to one or more subsequent compounds.

The one or more subsequent compounds formed in the intermediate step 3 are at least partially separated in the secondary fractionation 4. Of the

Intermediate step 3 is carried out in such a way that no more than 0.8% of the alpha-olefin predominantly contained in the primary fraction or its part subjected to the intermediate step is converted.

In Figure 2, the results of a series of tests are shown, which were carried out with Lewatit K-2649 as a catalyst (a macroporous sulfocationite as in Examples 2 and 3 above) and with different amounts of water used as a moderator, so that here the advantages of one embodiment of the present invention. In the diagram of FIG. 2, the (desired) conversion of 2-ethyl-1-butene is given on the abscissa and the (undesired) conversion of 1 -flexes is given on the ordinate, in each case in percent.

The solid line with square data points illustrates the values ​​achieved without water. The dashed line with round data points illustrates the values ​​achieved with an amount of water of 60 ppm by weight. The dotted line with triangular data points illustrates the values ​​achieved with a water quantity of 100 ppm by weight. The dash-dotted line with star-shaped data points illustrates the values ​​achieved with a water quantity of 130 ppm by weight.

The values ​​illustrated in FIG. 2 clearly show that a purely dry application leads to high losses of 1-hexen. An application with about 100 to 130 ppm by weight of water at the reactor outlet, as can result in one embodiment of the present invention, leads to considerable improvements with regard to these losses.

WE CLAIMS

1. Process (100) for the production of linear alpha-olefins, in which

Ethylene in a feed mixture is subjected to a catalytic oligomerization (1) to obtain a product mixture which contains alpha-olefins with different chain lengths and secondary compounds,

a primary fraction is formed in a primary fractionation (2) using at least part of the product mixture and a secondary fraction is formed in a secondary fractionation (4) using at least a part of the primary fraction,

- The primary fractionation (2) and the secondary fractionation (4) are carried out in such a way that the primary fraction and the secondary fraction contain predominantly one of the alpha-olefins and are poor in or free of other alpha-olefins, the primary fraction is one or more of the Contains secondary compounds, and the secondary fraction compared to the primary fraction in which one or more secondary compounds is depleted or free thereof, and

in an intermediate step (3) between the primary fractionation and the secondary fractionation, to which at least part of the primary fraction is subjected, the one or more secondary compounds are converted at least in part to one or more subsequent compounds and the one or more subsequent compounds in at least partially separated from secondary fractionation,

characterized in that

- the intermediate step (3) is carried out in such a way that no more than 0.8% of the alpha-olefin predominantly contained in the primary fraction or its part subjected to the intermediate step is converted, and

the intermediate step in the presence of 20 ppm by weight to 200 ppm by weight

Water is carried out as a reaction moderator and using a strongly acidic ion exchange resin.

2. The method according to claim 1, wherein a macroporous sulfocationite is used as the strongly acidic ion exchange resin.

3. The method according to claim 2, wherein Lewatit K-2649 is used as the macroporous sulfocationite.

4. The method according to any one of the preceding claims, wherein the strongly acidic ion exchange resin has a volume-related capacity of at least 4 eq / kg.

5. The method according to any one of the preceding claims, wherein the intermediate step is carried out at a bed speed of 5 to 40 h 1 .

6. The method according to any one of the preceding claims, in which 0.1 to 0.8% of the alpha-olefin predominantly contained in the primary fraction or its part subjected to the intermediate step are reacted.

7. The method according to any one of the preceding claims, in which the intermediate step is carried out at a temperature level of 60 G to 100 G and / or is carried out at a pressure level of 1.0 to 4.0 bar absolute pressure.

8. The method according to any one of the preceding claims, in which the product mixture contains as main component (s) 1-hexene and / or 1-octene in a content of more than 50, 60, 70, 80 or 90 wt .-%.

9. The method according to any one of the preceding claims, in which the alpha-olefin which the primary fraction and the secondary fraction predominantly contain is 1-hexene, the 1-hexene content being more than 90% by weight

10. The method according to claim 9, in which the secondary compound or one of the secondary compounds is 2-ethyl-1-butene and / or in which the secondary compound or one of the secondary compounds is 3-methyl-2-pentene.

1 1. Process according to one of Claims 1 to 8, wherein the alpha-olefin which the primary fraction and the secondary fraction predominantly contain is 1-octene, the 1-octene content being more than 90% by weight.

12. The method according to claim 1 1, in which the secondary compound or one of the secondary compounds is 2-ethyl-1-hexene and / or in which the subsequent compound or one of the secondary compounds is 3-methyl-1 -heptene.