METHOD FOR OBTAINING LONG-CHAIN LINEAR ALKENES

Abstract

The invention relates to a method for obtaining a linear, internal C.sub.10-C.sub.16 alkene from an unsubstituted linear, terminal C.sub.10-C.sub.16 alkene in the presence of a metal precursor. The unsubstituted linear terminal C.sub.10-C.sub.16 alkene is mixed with a supported or non-supported metal precursor. The mixture obtained is heated at a temperature of between 150 C. and 300 C., wherein the metal precursor gives rise to the in-situ formation of isolated metal atoms which act as catalysts. The metal precursor is used in an amount of less than 100 ppm by weight with respect to the unsubstituted linear terminal C.sub.10-C.sub.16 alkene. The mixing and heating are carried out in the absence of a solvent, The metal precursor is Ru.

Claims

1. A method for generating an internal and linear C.sub.10-C.sub.16 alkene which comprises the following steps: i) mixing an unsubstituted linear terminal C.sub.10-C.sub.16 alkene with a supported or non-supported metal precursor; and ii) heating the mixture obtained in step (i) at a temperature of between 150 C. and 300 C., wherein the metal precursor gives rise to the in situ formation of isolated metal atoms which act as catalysts, characterized in that: the metal precursor is used in an amount of less than 100 ppm by weight with respect to the unsubstituted linear terminal C.sub.10-C.sub.16 alkene, wherein: steps (i) and (ii) are carried out in the absence of a solvent, and the metal of the metal precursor of step (i) is Ru.

2. The method according to claim 1, wherein the unsubstituted linear terminal C.sub.10-C.sub.16 alkene of step (i) is an unsubstituted linear terminal C.sub.12-C.sub.14 alkene.

3. The method according to claim 1, wherein the unsubstituted linear terminal C.sub.12-C.sub.14 alkene of step (i) is selected from 1-dodecene and 1-tetradecene.

4. The method according to claim 1, wherein the metal precursor is selected from Ru.sub.3(CO).sub.12, RuCl.sub.3, Ru(C.sub.4H.sub.8).sub.2COD, Ru(PPh).sub.3Cl.sub.2, Ru nanoparticles in colloidal form, and Ru nanoparticles as a pure metal.

5. The method according to claim 1, wherein the metal precursor is supported on inorganic oxides.

6. The method according to claim 1, wherein the unsubstituted linear terminal C.sub.10-C.sub.16 alkene of step (i) is present in an amount of between 10,000 equivalents and 100,000,000 equivalents with respect to the metal precursor.

7. The method according to claim 1, wherein the metal precursor is used in an amount of between 1 ppm and 100 ppm by weight with respect to the unsubstituted linear terminal C.sub.10-C.sub.16 alkene.

8. The method according to claim 1, wherein step (ii) is carried out in a batch-type reactor with simple stirring or in a tank-type continuous reactor stirred with a continuous flow or fixed bed.

9. The method according to claim 1, wherein the temperature of step (i) is between 200 C. and 250 C.

10. The method according to claim 1, wherein step (ii) is carried out at a pressure of between 1 bar and 20 bar.

11. The method according to claim 1, wherein step (ii) is carried out under an inert atmosphere.

12. The method claim 1, wherein the reaction time of step (ii) is between 0.5 h and 72 h.

13. The method according to claim 1, wherein: the metal precursor is selected from Ru.sub.3(CO).sub.12, RuCl.sub.3, Ru(C.sub.4H.sub.8).sub.2COD, Ru(PPh).sub.3Cl.sub.2, Ru nanoparticles in colloidal form, and Ru nanoparticles as a pure metal; and the metal precursor is supported on inorganic oxides.

14. The method according to claim 1, wherein: the unsubstituted linear terminal C10-C16 alkene of step (i) is present in an amount of between 10,000 equivalents and 100,000,000 equivalents with respect to the metal precursor; and the metal precursor is used in an amount of between 1 ppm and 100 ppm by weight with respect to the unsubstituted linear terminal C10-C16 alkene.

15. The method according to claim 1, wherein step (ii) is carried out: at a pressure of between 1 bar and 20 bar; and under an inert atmosphere.

16. The method according to claim 1, wherein: the unsubstituted linear terminal C.sub.10-C.sub.16 alkene of step (i) is an unsubstituted linear terminal C.sub.12-C.sub.14 alkene; the metal precursor is selected from Ru.sub.3(CO).sub.12, RuCl.sub.3, Ru(C.sub.4H.sub.8).sub.2COD, Ru(PPh).sub.3Cl.sub.2, Ru nanoparticles in colloidal form, and Ru nanoparticles as a pure metal; and the metal precursor is supported on inorganic oxides.

17. The method according to claim 1, wherein: step (ii) is carried out in a batch-type reactor with simple stirring or in a tank-type continuous reactor stirred with a continuous flow or fixed bed; the temperature of step (i) is between 200 C. and 250 C.; step (ii) is carried out at a pressure of between 1 bar and 20 bar; step (ii) is carried out under an inert atmosphere; and the reaction time of step (ii) is between 0.5 h and 72 h.

18. The method according to claim 1, wherein: the unsubstituted linear terminal C.sub.10-C.sub.16 alkene of step (i) is an unsubstituted linear terminal C.sub.12-C.sub.14 alkene; the metal precursor is selected from Ru.sub.3(CO).sub.12, RuCl.sub.3, Ru(C.sub.4H.sub.8).sub.2COD, Ru(PPh).sub.3Cl.sub.2, Ru nanoparticles in colloidal form, and Ru nanoparticles as a pure metal; the metal precursor is supported on inorganic oxides; the unsubstituted linear terminal C.sub.10-C.sub.16 alkene of step (i) is present in an amount of between 10,000 equivalents and 100,000,000 equivalents with respect to the metal precursor; the metal precursor is used in an amount of between 1 ppm and 100 ppm by weight with respect to the unsubstituted linear terminal C.sub.10-C.sub.16 alkene; step (ii) is carried out in a batch-type reactor with simple stirring or in a tank-type continuous reactor stirred with a continuous flow or fixed bed; the temperature of step (i) is between 200 C. and 250 C.; step (ii) is carried out at a pressure of between 1 bar and 20 bar; step (ii) is carried out under an inert atmosphere; and the reaction time of step (ii) is between 0.5 h and 72 h.

19. The method according to claim 1, wherein: the unsubstituted linear terminal C.sub.12-C.sub.14 alkene of step (i) is selected from 1-dodecene and 1-tetradecene; the metal precursor is selected from Ru.sub.3(CO).sub.12, RuCl.sub.3, Ru(C.sub.4H.sub.8).sub.2COD, Ru(PPh).sub.3Cl.sub.2, Ru nanoparticles in colloidal form, and Ru nanoparticles as a pure metal; and the metal precursor is supported on inorganic oxides.

20. The method according to claim 1, wherein: the unsubstituted linear terminal C.sub.12-C.sub.14 alkene of step (i) is selected from 1-dodecene and 1-tetradecene; the metal precursor is selected from Ru.sub.3(CO).sub.12, RuCl.sub.3, Ru(C.sub.4H.sub.8).sub.2COD, Ru(PPh).sub.3Cl.sub.2, Ru nanoparticles in colloidal form, and Ru nanoparticles as a pure metal; the metal precursor is supported on inorganic oxides; the unsubstituted linear terminal C.sub.10-C.sub.16 alkene of step (i) is present in an amount of between 10,000 equivalents and 100,000,000 equivalents with respect to the metal precursor; the metal precursor is used in an amount of between 1 ppm and 100 ppm by weight with respect to the unsubstituted linear terminal C.sub.10-C.sub.16 alkene; step (ii) is carried out in a batch-type reactor with simple stirring or in a tank-type continuous reactor stirred with a continuous flow or fixed bed; the temperature of step (i) is between 200 C. and 250 C.; step (ii) is carried out at a pressure of between 1 bar and 20 bar; step (ii) is carried out under an inert atmosphere; and the reaction time of step (ii) is between 0.5 h and 72 h.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0076] FIG. 1 shows the 1H-NMR spectrum of the starting 1-dodecene (A) and the reaction product (B) after 4.5 h of reaction with 0.0005 mol % of Ru(C.sub.4H.sub.8).sub.2(COD).

[0077] FIG. 2 shows the 1H-NMR spectrum of the starting 1-tetradecene (A) and the reaction product (B) after 4.5 h of reaction with 0.0005 mol % of Ru(C.sub.4H.sub.8).sub.2(COD).

EXAMPLES

[0078] Next, the invention will be illustrated by means of assays carried out by the inventors that demonstrate the effectiveness of the product of the invention.

[0079] Table 1 shows the results with 1-dodecene for a Ru-type catalyst. Migration of the double bond occurs with only 5 ppm by weight of Ru catalyst (entry 6) at >95% conversion, although with a long reaction time (20 h). This linear terminal olefin with alkyl chain has a boiling point above 200 C. and a good thermal stability, which allows the possible conversion thereof to internal alkenes at temperatures above 150 C. and with improved conversions in less time. Table 1 also shows that, at 200 C., isomerization continues at >97% conversions after 4.5 h. In this case, it should be mentioned that, depending on the amount of catalyst, the internal alkene mixture is different. For example, there are 72% of 2-dodecene and 18% of other more internal alkenes by using 1 ppm by weight of catalyst, and 26% of 2-dodecene with 5 ppm by weight. The results are consistent for starting materials (1-dodecene) of several commercial companies. In any case, the final linear internal alkene mixture is consistent for a given amount of catalyst.

##STR00001##

TABLE-US-00001 TABLE 1 T = 150 C. T = 200 C. Conditions Conv. Yield (%) Conditions Conv. Yield (%) Exp. (mol %) t (h) (%) 2-alkene Others (mol %) t (h) (%) 2-alkene others 1 0.05 2 100.0 20.2 79.8 0.0005 4.5 97.3 26.0 71.3 2 0.01 2 100.0 51.2 48.8 0.00025 10 95.6 48.7 46.9 3 0.001 2 91.8 79.0 12.8 0.0001 17 90.5 72 18.5 4 20 100.0 29.4 70.6 5 0.0005 2 88.3 78.9 9.4 6 20 95.6 49.4 46.2 7 0.0001 21 83.5 76.6 6.9

[0080] Table 2 shows the results for 1-tetradecene at reaction temperatures of 150 and 200 C. As evaluated above for 1-dodecene, higher conversions are obtained in less time at 200 C., with >97% conversion with 5 ppm by weight of Ru after 5 h. There is a need to take into account that a >95% conversion is difficult to achieve with any industrial method and is highly beneficial for the final application of the product.

##STR00002##

TABLE-US-00002 TABLE 2 T = 150 C. T = 200 C. Conditions Conv. Yield (%) Conditions Conv. Yield (%) Exp. (mol %) t (h) (%) 2-alkene Others (mol %) t (h) (%) 2-alkene others 1 0.05 2 100.0 33.5 66.5 0.0005 5 97.7 33.5 64.2 2 0.01 2 100.0 77.9 22.1 0.00025 22 86.7 65.2 21.5 3 0.001 5 90.5 75.5 15.0 0.0001 22 66.7 59.6 7.1 4 20 100.0 3.3 60.7 5 0.0005 5 89.6 78.8 10.8 6 21 95.6 44.5 51.1 7 0.0001 21 54.5 52.0 2.5

Example 1: Method for the Migration of a Double Bond in 1-Dodecene with 5 ppm by Weight of the Catalyst Ru(C.SUB.4.H.SUB.8.).SUB.2.COD

[0081] 1-Dodecene (27 g) was charged into a 50 ml flask equipped with a magnetic stirrer and the Ru(methallyl).sub.2COD catalyst (0.0005 mol %) was added. The flask was closed with a septum, nitrogen atmosphere was created, and the flask was placed in a preheated oil bath at 200 C. under magnetic stirring for a given reaction time. Aliquots were taken from the reaction mixture to monitor the reaction over time by means of GC and NMR. It should be noted that stock solutions of the Ru catalyst in dichloromethane (which evaporates during reaction) were prepared, since the amounts used are too small to be weighed. To prepare these solutions, volumetric flasks were used with dichloromethane as solvent. For GC analysis, 5.6 l of the reaction mixture were diluted with 1 ml of ethyl acetate. For NMR analysis, 20 mg of the reaction mixture were dissolved in deuterated chloroform (CDCl.sub.3 signal: singlet, 7.26 ppm), 15 mg of 1,2-dichloroethane were also added (signal: singlet, 3.73 ppm) as an internal standard for calculating the conversion of the reaction.

[0082] FIG. 1 shows how the starting terminal alkene disappears and the desired products appear.

Example 2: Method for the Migration of Double Bond in 1-Tetradecene with 5 ppm by Weight of the Catalyst Ru(C.SUB.4.H.SUB.8.).SUB.2.COD

[0083] 1-Tetradecene (32 g) was charged into a 50 ml flask equipped with a magnetic stirrer and the Ru(methallyl).sub.2COD catalyst (0.0005 mol %) was added. The flask was closed with a septum, nitrogen atmosphere was created, and the flask was placed in a preheated oil bath at 200 C. under magnetic stirring for a given reaction time. Aliquots were taken from the reaction mixture to monitor the reaction over time by means of GC and NMR. It should be noted that stock solutions of the Ru catalyst in dichloromethane (which evaporates during reaction) were prepared, since the amounts used are too small to be weighed. To prepare these solutions, volumetric flasks were used with dichloromethane as solvent. For CG analysis, 5.6 l of the reaction mixture were diluted with 1 ml of ethyl acetate. For NMR analysis, 20 mg of the reaction mixture were dissolved in deuterated chloroform (CDCl.sub.3 signal: singlet, 7.26 ppm), 15 mg of 1,2-dichloroethane were also added (signal: singlet, 3.73 ppm) as an internal standard for calculating the conversion of the reaction. FIG. 2 shows how the starting terminal olefin disappears and the desired products appear.

Example 3: Method for the Migration of a Double Bond in 1-Dodecene in a Stirred Reactor with a Solid Ru Catalyst on Silica

[0084] A solid Ru catalyst on silica, prepared by the impregnation of RuCl.sub.3 on silica with a large surface area for a final load of 1% by weight of Ru, was added into a 50 ml flask equipped with a magnetic stirrer so as to achieve 0.001 mol % with respect to 1-dodecene (27 g), which was added later. The flask was closed with a septum, nitrogen atmosphere was created, and the flask was placed in a preheated oil bath at 200 C. under magnetic stirring for a given reaction time. Supernatant samples were taken to monitor the reaction over time by means of GC and NMR. For NMR analysis, 20 mg of the supernatant were dissolved in deuterated chloroform (CDCl.sub.3 signal: singlet, 7.26 ppm), 15 mg of 1,2-dichloroethane were also added (signal: singlet, 3.73 ppm) as an internal standard for calculating the conversion of the reaction.