Background to the Invention The applicant is aware that olefins in the Cs to C14 range may be used as detergent and plasticizer precursors as well as for alkylation of benzene, and that C15 to C, 8 olefin ranges may be used as drilling fluids and drilling fluid precursors, amongst other uses.

Conventional thinking was that linear olefins may be used to produce linear alkyl benzene and linear oxo-alcohols which could be used to produce detergents and plasticizers which were believed to be both bio-degradable and suitable for their intended purpose. Thus, previously efforts were concentrated on producing linear oxo-alcohols and lineal alkyl benzene, and thus efforts were focused on linear olefins from which these could be made.

Recently, however, a new wave of thinking has lead to the belief that non-liner oxo-alcohols as well as non-linear alkyl chain alkyl benzene could be used alone or together with their linear counterparts for the production of

said detergents and plasticizers. In particular short chain branched olefins are believed best suited to produce such non-liner products. Thus, recent efforts have concentrated on the delinearization of the linear olefins in order to use such olefins in the production of the non-liner products.

Summary of the Invention Surprisingly, after extensive research, the applicant has found that a peculiar olefin composition in the Cg to C, 8 range, having both linear and non- linear olefins may be made by metathesis of Fischer-Tropsch olefins in the C5 to C15 range.

Thus, according to a first aspect of the invention, there is provided a high temperature metathesis process for the metathesis of Fischer-Tropsch olefins in the C5 to C15 range, said metathesis process including the step of subjecting a Fischer-Tropsch olefin feedstock in the C5 to Cis range to metathesis reaction conditions, said olefin feedstock including mono-methyl branched olefins.

The high temperature metathesis process may be carried out at a temperature of between 300°C to 600°C.

Typically the high temperature metathesis process is carried out at a temperature of between 450°C and 550°C.

The operating pressure of the high temperature metathesis process may be between 1 and 30 bar, or even higher.

The high temperature metathesis process may use a tungsten or molybdenum based catalyst, for example, W03 or MoOs, supported or unsupported, with or without co-catalysts. The support can typically be Si02, AI203, Zr02, Ti02, or mixtures thereof.

The high temperature metathesis process Fischer-Tropsch olefinic feedstock in the C5 to C15 range may include linear alpha olefins, mono-methyl branched olefins, paraffins, dienes, aromatics, and the like.

Typically, the Fischer-Tropsch olefinic feedstock includes one or more olefins selected from the C5 to Cs range.

The product of the high temperature metathesis process may include one or more mono-methyl branched olefins in the Cs to Cis range.

The product of the high temperature metathesis process may include one or more linear olefins in the Cs to C18 range.

The product of the high temperature metathesis process may include one or more mono-methyl branched olefins and one or more linear olefins in the C9 to Ci8 range. The olefins of the product may be internal olefins.

The product of the high temperature metathesis process may be used in the production of alkyl benzene, plasticizers, detergents, drilling fluids, and the like, having both a linear fraction and a branched fraction (for alkyl benzene the alkyl chain is branched or linear).

Typically, the branched fraction will be mono-methyl branched.

However, the branching may be di-methyl and/or ethyl.

According to a second aspect of the invention, there is provided a high temperature metathesis process for the metathesis of olefins in the C5 to C15 range, said metathesis process including the step of subjecting an olefinic feedstock in the C5 to C15 range to metathesis reaction conditions, the process including the recycling of a part of the product of the metathesis reaction to the reaction to increase the selectivity for a desired product range.

The olefinic feedstock may be a Fischer-Tropsch olefinic feedstock including mono-methyl branched olefins.

Typically, the olefinic feedstock includes one or more olefins in the C5 to Cs range.

Where the desired product range includes olefins in the Cg to Cr8 range, the process includes a separation stage wherein a recycle fraction in the C5 to C8 range is separated from the product and recycled to the reaction.

The quantity of recycle in the feedstock may be selected to provide a C9 and higher selectivity of above 50%.

Generally, the quantity of recycle in the feedstock is selected to provide a Cs and higher selectivity of above 50%.

Typically, the recycle makes up between 20% and 80% of the reaction feedstock.

Usually, the recycle makes up between about a third and three quarters of the reaction feedstock.

The total yield of high temperature metathesis process product in the Cs to C18 range is above 40%.

Typically, the total yield of high temperature metathesis process product in the Cg to C18 range is about 50%.

The total feedstock conversion of the high temperature metathesis process of the invention is typically in the range of 60% to 90%, usually about 80%.

The ratio of linear to branched high temperature metathesis process products is typically greater than 1: 1.

Usually, the ratio of linear to branched high temperature metathesis process products is greater than 2 : 1.

Generally, the ratio of linear to branched high temperature metathesis process products is about 3: 1.

The branching of the high temperature metathesis process products is predominantly mono-methyl branching, although some di-methyl, and/or ethyl branching may also be present.

The product of the high temperature metathesis process may be used in the production of alkyl benzene, plasticizers, detergents, drilling fluids, and the like, having both a linear fraction and a branched fraction (for alkyl benzene the alkyl chain is branched or linear), the ratio of linear to branched fractions being related to the ratio of linear to branched high temperature metathesis process products used in their production.

Description of the Drawing and Examples The invention will now be described, by way of non-limiting illustration only, with reference to the accompanying line diagram.

In the diagram, reference numeral 10 generally indicates a high temperature metathesis process broadly in accordance with the invention.

The process 10 includes a reactor 12 operated at between 450°C and 550°C and at an operating pressure of between 1 and 30 bar. A Fischer- Tropsch olefinic feedstock 14 including mono-methyl branched olefins, is fed into the reactor 12. The feedstock 14 includes olefins in the C5 to Cs range.

Usually the feedstock 14 will be purified of oxygenates which may poison the catalyst by extractive distillation (not shown), prior to being fed to the reactor 12.

The reaction product 16 includes both linear and branched internal olefins in the C2 to C, range.

The reaction product 16 is fed to a separator 18 where it is cut into a light product stream 20 including C2 to C4, a recycle stream 22 including C5 to C8, and a heavy product 24 including product in the desired Cs to Cr8 range.

The recycle stream 22 is combined with the feedstock 14 to form the total feedstock of the reactor 12.

The recycle stream 22 is between a third and three quarters of the feedstock 14.

The total yield of heavy product stream 24 is about 50%, while the feedstream 14 conversion is about 80%, with a selectivity for Cs to Cis of about 60%.

The ratio of linear to branched product in heavy product stream 24 is about 3 : 1 Examples Several runs were made by passing olefin containing feed downwards through a vertical pipe reactor, unless otherwise stated. This reactor (25.4 mm in diameter and 400 mm in length) was positioned in a temperature- controlled electric furnace with a thermocouple positioned in the catalyst bed to monitor reaction temperatures.

About 100 mm depth of glass beads (2 mm diameter) were placed at the bottom of the pipe reactor supported by a layer of quartz wool. Another layer of quartz wool was placed on top of the glass beads as support for the catalyst bed comprising of about 12 g of catalyst. This was topped with another layer of quartz wool and the remainder of the reactor filled with glass beads. The catalyst was activated by heating at 550°C in flowing air for 12 hours, followed by heating at 600°C for 2 hours under a flow of nitrogen and finally the catalyst was cooled under a flow of nitrogen to reaction temperature (typically500°C).

Example 1 In this Example a catalyst in the form of a WO3 supported on Si02 was used, in which the W03 and Si02 were in a mass ratio of 8: 92. The process

was operated in the temperature range of 400 to 550°C and at a LHSV of 1 h- . As a feed was used a C7 SLO narrow cut after NMP extraction, containing 3-methyl-1-hexene (0.7870%), 5-methyl-1-hexene (1.9068%), 4-methyl-1- hexene (3.1737%), 2-methyl-1-hexene (4.1847%), 2-methylhexane (1.6501%), 3-methylhexane (2.8000%), 1-heptene (74.5710%), n-heptane (6.3012%), 2-methyl-2-hexene (0.6832%), 3-heptene (0.3163%), 2-heptene (0.7038%) and dienes, cyclic olefins and aromatics (2.4386%) amongst others, based on mass% calculations. Results are set forth in the following table, Table 1 : Table 1 Temp °C 400 450 475 500 525 550 C7 Conversion (% 4.4 20. 4 50. 0 65. 9 71. 9 78.4 Yield C9-C14 (%) 2.4 8. 9 20. 3 23. 9 20. 2 13.9 -C14(%)55.643.940.636.328.117.7SelectivityC9 Selectivity C2 0. 4 1 0. 3 0. 3 0. 7 1. 2 2.7 Selectivity C3 5. 0 2. 6 2. 7 4. 6 7. 7 14.0 Example 2 In this Example a catalyst in form of a WOs supported on Si02 was used, in which the WOs and Si02 were in a mass ratio of 8: 92. The process was operated at 500°C and by recycling some of the olefins formed back to the reactor. As a feed was used a C7 SLO narrow cut after NMP extraction, containing 3-methyl-1-hexene (0.7870%), 5-methyl-1-hexene (1.9068%), 4- methyl-1-hexene (3.1737%), 2-methyl-1-hexene (4.1847%), 2-methylhexane

(1.6501 %), 3-methylhexane (2.8000%), 1-heptene (74.5710%), n-heptane (6.3012%), 2-methyl-2-hexene (0.3163%), 2-heptene (0.7038%) and dienes, cyclic olefins and aromatics (2.4386%) amongst others, based on mass% calculations. Results are set forth in the following table, Table 2: Table 2 C8YieldC9-C10C11-C14C15-C18C8-C14RunFeed Conversion (%) Yield (%) Yield (%) Yield (%) Yield (%) (%) 4.87.036.54.048.31a89.7 -25--96. 4 2. 1 22. 1 33. 5 5. 5 57.7 4.633.027.10.564.73c90.6 4 90. 1 11. 8 31. 3 22. 8 0. 2 65.9

(a) 1.0 LHSV based on fresh feed ; 6.0 LHSV with recycle (1 : 5 recycle ration); (Recycle C5-C10) (b) 1.4 LHSV based on fresh feed, @ 5. 6 LHSV with recycle (1 : 3 recycle ratio); (Recycle C5-C9) (c) 1.4 LHSV based on fresh feed ; 5.6 LHSV with recycle 1 : 3 recycle ratio; (Recycle C5/6-C8) (d) 2.0 LHSV based on fresh feed ; 5.0 LHSV with recycle 1 : 1.5 recycle ratio); Recycle C4/5-C7) Example 3 In this Example a catalyst in the form of a W03 supported on Si02 were in a mass ratio of 8: 92. The process was operated at 500°C and at a LHSV of 3 h-1. As a feed was used a C5 SLO co-monomer grade cut containing 99% 1-pentene. The C5-C7 fraction was recycled (1: 1 recycle ratio) back to the

reactor in order to increase the yield towards the C8-C14 fraction. Results are set forth in the following table, Table 3: Table 3 Temp °C 500 Ce Conversion (% 88.2 Yield C9-C14 (%) 19. 9 Selectivity Cs-C14 (%) 22. 6 Selectivity C2 5. 2 Selectivity C3 19. 4

The applicant believes that it is an advantage of the invention as illustrated, that the high operating temperatures result in a high degree of resistance to poisoning of the metathesis catalyst by feedstock components, such as branched olefins, dienes, aromatics, and the like.

The applicant believes that it is a further advantage of the invention as illustrated that by recycling a cut of the product which is below the desirable carbon length range, high selectivity to desired products is achieved..