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Process for chain growth of olefins

IP.com Disclosure Number: IPCOM000009919D
Publication Date: 2002-Sep-27

Publishing Venue

The IP.com Prior Art Database

Abstract

A process of increasing the carbon chain length of an olefinic compound comprising the steps of providing a starting olefinic compound and subjecting it to hydroformylation to produce an aldehyde and/or alcohol with an increased carbon chain length compared to the starting olefinic compound. Optionally the aldehyde that may form during the hydroformylation reaction is hydrogenated to convert it to an alcohol which has an increased carbon chain length compared to the starting olefinic compound. The alcohol with the increased carbon chain length is subjected to dehydration to produce an olefinic compound with an increased carbon chain length compared to the starting olefinic compound. The invention also relates to olefinic compounds produced by the process.

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Technical Field

This invention relates to a process of increasing the carbon chain length of olefinic compounds.  The invention also relates to olefinic compounds produced by this process.

Background Art

There is a high demand for longer chain α-olefins, especially even numbered α-olefins such as 1-hexene and 1-octene.  1-Hexene and 1-octene are used, amongst others, as co-monomers in polyethylene production where they serve as plasticisers e.g. in the preparation of linear low-density polyethylene.

One method of producing olefins is through an olefin metathesis reaction.  A disadvantage of this type of reaction is that it is difficult to control the reaction to produce only one specific olefin, and the majority of olefins produced by this process are internal olefins.  Metathesis reactions are accordingly not very suitable for preparing α-olefins such as 1-hexene or 1-octene.  One type of metathesis reaction, namely ethenolysis between an internal olefin and ethylene, can potentially yield α-olefins, but the technology is suffering from equilibrium and selectivity limitations.  Furthermore, ethenolysis of an internal olefin would result in an olefin with a shorter carbon chain than the starting internal olefin.

1-Hexene can also be produced by means of trimerisation of ethylene.  Although this is a well-known method for producing 1-hexene, it has the disadvantage that C4, C8 and C10 impurities are also produced.

The inventors of the present invention have now developed a novel process of increasing the carbon chain length of olefinic compounds, including and especially α-olefins.  Accordingly, shorter α-olefins such as 1-pentene can be converted to 1-hexene.

Fischer-Tropsch technology produces a large range of hydrocarbon products following an Anderson-Schulz-Flory distribution.  This means that more 1-pentene is produced than 1-hexene.  The market demand for 1-pentene is small with the result that most of the 1-pentene ends up in a fuel pool, resulting in a fuel alternative value.  On the other hand 1-hexene is sold at a much higher value.  The same arguments as for 1-pentene hold for heptenes and butenes.  It is believed that with the process of the present invention 1-butene, 1-pentene and/or 1-heptene can undergo controlled chain growth reactions to yield 1-hexene and/or 1-octene.

Disclosure of the Invention

According to the present invention there is provided a process of increasing the carbon chain length of an olefinic compound comprising the steps of :-

-                providing a starting olefinic compound  and subjecting it to hydroformylation to produce an aldehyde and/or alcohol with an increased carbon chain length compared to the starting olefinic compound;

-                optionally, hydrogenating the aldehyde that forms during the hydroformylation reaction to convert it to an alcohol which has an increased carbon chain length compared to the starting olefinic compound; and

-               subjecting the alcohol with the increased carbo...