Butadiene telomerization catalyst preparation and use thereof

Abstract

Catalyst compositions are prepared by contacting a palladium source and 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane and a methoxyocta-diene compound, in a primary aliphatic alcohol, under suitable conditions including a ratio of equivalents of palladium to equivalents of 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane ranging from greater than 1:1 to 1:1.3. The result is a complex of palladium, a 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaada-mantane ligand, and a ligand selected from a methoxyoctadiene ligand, an octadienyl ligand, or a protonated octadienyl. Such complexes may, in solution, exhibit surprising solubility and storage stability and are useful in the telomerization of butadiene, which is a step in the production of 1-octene.

Claims

1. A process for preparing a catalyst composition useful for catalyzing the telomerization of butadiene comprising dissolving as reagents a palladium source, 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane, as set forth in structures (I) and (II), ##STR00004## and a methoxyoctadiene compound in a primary aliphatic alcohol, such that the ratio of equivalents of the palladium to equivalents of the 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane ranges from greater than 1:1 to 1:1.3, to form a catalyst composition comprising a complex comprising palladium, a 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane ligand, and a ligand selected from a methoxyoctadiene ligand, an octadienyl ligand, or a protonated octadienyl ligand, in the primary aliphatic alcohol.

2. The process of claim 1 wherein: (a) the palladium source is selected from palladium acetylacetonate, palladium formate, palladium acetate, palladium propionate, palladium octanoate, palladium carbonate, palladium hydroxide, palladium citrate, tetrakis(triphenylphosphine) palladium, bis(1,5-cyclooctadiene) palladium, bis(dibenzylideneacetone) palladium, and combinations thereof; (b) the methoxyoctadiene compound is selected from 1-methoxy-2,7-octadiene, 3-methoxy-1,7-octadiene, and combinations thereof; (c) the primary aliphatic alcohol is selected from methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, glycerol, and combinations thereof; or (d) a combination thereof.

3. The process of claim 1, wherein the palladium source is selected from palladium acetylacetonate, palladium formate, palladium acetate, palladium propionate, palladium octanoate, palladium carbonate, palladium hydroxide, palladium citrate, tetrakis(triphenylphosphine) palladium, bis(1,5-cyclooctadiene) palladium, bis(dibenzylideneacetone) palladium, and combinations thereof.

4. The process of claim 1, wherein the methoxyoctadiene compound is selected from 1-methoxy-2,7-octadiene, 3-methoxy-1,7-octadiene, and combinations thereof.

5. The process of claim 1, wherein the primary aliphatic alcohol is selected from methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, glycerol, and combinations thereof.

6. The process of claim 1, wherein the process further comprises adding (a) a carboxylic acid; (b) a promoter selected from alkoxides, enolates, phenoxides, borohydrides, and hydrazides, all of alkali metals; alkaline earth metals and quaternary ammoniums; alkali metal salts; or a combination thereof; or (c) a combination thereof.

7. The process of claim 1, wherein the process further comprises adding a carboxylic acid.

8. The process of claim 1, wherein the process further comprises adding a promoter.

9. The process of claim 8, wherein the promoter is selected from alkoxides, enolates, phenoxides, borohydrides, and hydrazides, all of alkali metals; alkaline earth metals and quaternary ammoniums; alkali metal salts; or a combination thereof.

10. The process of claim 1, wherein the ratio of equivalents of the palladium source to the equivalents of the 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phospha-adamantane ranges from 1:1.2 to 1:1.3.

Description

EXAMPLE 1

(1) 1:1 equivalents ratio, Pd to TMTPA-di-OMe.

(2) In the glovebox, dissolve 94 milliliters (mL) methanol (MeOH), 29 mL 1-methoxy-2,7-octadiene (MOD-1), and 91 microliters (μL) acetic acid (AcOH) to prepare a stock solution that is 25 weight percent (wt %) MOD-1 and 75 wt % methanol.

(3) Dissolve palladium(II) acetylacetonate (Pd(acac).sub.2) (0.0196 grams (g), 0.000064 moles (mol)), 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane (TMTPA-di-OMe) (0.0227 g, 0.000064 mol), and 5 mL of the stock solution that is 25 wt % in MOD-1 described above to form an inventive catalyst solution. Allow the catalyst to stir for 3 days at 20° C. before use.

(4) Add dibutyl ether (Bu.sub.2O, 5 mL) (GC standard), MeOH (13.35 mL), methylcyclohexane (MeCy, 1 mL) (a liquid fill that approximates conditions in a plant reactor), the catalyst (0.15 mL), and a portion of a solution of sodium methoxide (NaOMe) in MeOH (19.32 millimolar (mM), 0.5 mL) to a Fisher-Porter bottle. Seal the bottle with a valve equipped with a septum port. Distill butadiene (approximately 5 mL) into a gas-tight syringe, and determine the mass of butadiene by weighing the syringe before and after addition to the reactor. Inject the butadiene into the Fisher-Porter bottle with the needle placed below the surface of the solution. Place the reaction vessels into preheated oil baths. Remove 1 mL reaction aliquots at the 30 minute (min), 1 hour (h), 2 h, and 4 h time points through a 24 inch (24″) needle equipped with a gas-tight valve, and subject each aliquot to gas chromatographic (GC) analysis.

(5) Perform GC analyses on an AGILENT™ 7890A chromatograph (AGILENT is a trademark of Agilent Technologies) using a DB-1701 column at constant gas flow. Use dibutyl ether as the internal standard, and determine response factors based on materials of known composition. GC Method:

(6) Column: LTM-DB-1701; Length: 30 meters (m); Diameter: 320 micrometers (μm); Film thickness: 1.0 μL; Mode: constant flow; Initial column flow: 1.27 milliliters per minute (mL/min).

(7) Front inlet: Mode: split; Initial temp: 250° C.; Pressure: 6.7 pounds per square inch (psi); Split ratio: 50:1.

(8) Detector: FID; Temp: 260° C.; H.sub.2 flow: 40 mL/min; Air flow: 400 mL/min; Make-up gas: He.

(9) Oven: 250° C.

(10) Low thermal mass (LTM) column: Initial temp: 50° C. and hold for 2 min; Ramp at 7.5° C./min. Total run time: 22 min.

(11) Observe no solids precipitation of the catalyst composition after storing for more than 4 weeks.

EXAMPLE 2

(12) After 2 weeks of storage of the catalyst composition of Example 1, conduct a telomerization reaction of butadiene using it, in duplicate, at 70° C. Conversion versus time is shown in Table 1.

(13) TABLE-US-00001 TABLE 1 Telomerization reaction run in duplicate at 70° C. Pd:TMTPA-di-OMe = 1:1. Conversion of Selectivity Yield Time (min) butadiene (%) MOD-1 (%) MOD-1 (%) 30 49.2/54.8 94.3/94.0 46.4/51.5 60 68.0/72.5 94.6/94.4 64.3/68.4 120 84.6/86.0 94.8/94.6 80.2/81.4 240 91.8/90.0 94.8/94.5 87.0/85.0

EXAMPLE 3

(14) 1:1.2 equivalents ratio, Pd to TMTPA-di-OMe.

(15) Prepare the catalyst as in Example 1, but with 0.0273 g (0.000073 mol) TMTPA-di-OMe. Observe that the catalyst shows no solids precipitation after storing for more than 4 weeks.

EXAMPLE 4

(16) After the 4 weeks catalyst storage, use the catalyst composition of Example 3 to conduct a telomerization reaction at 70° C. Conversion versus time is shown in Table 2.

(17) TABLE-US-00002 TABLE 2 Telomerization reaction run in duplicate at 70° C. Pd:TMTPA-di-OMe = 1:1.2. Conversion of Selectivity Yield Time (min) butadiene (%) MOD-1 (%) MOD-1 (%) 30 62.6/55.6 93.5/94.0 58.5/52.3 60 72.1/66.0 93.7/94.1 67.6/62.1 120 83.6/79.2 93.8/94.2 78.4/74.6 240 87.7/83.2 93.9/94.2 82.4/78.4

EXAMPLE 5

(18) 1:1.3 equivalents ratio, Pd to TMTPA-di-OMe.

(19) Prepare another catalyst by dissolving Pd(acac).sub.2 (0.3200 g, 0.0011 mol), TMTPA-di-OMe (0.5000 g, 0.0014 mol), 70% acetic acid in water (0.6400 g, 0.0011 mol), MOD-1 (9.1100 g, 0.0650 mol) in MeOH (27.34 g, 34.5 mL). Stir this catalyst for more than 3 days. Dissolve 0.75 g of NaOMe in 300 mL MeOH to make a stock solution of NaOMe promoter. Conduct a telomerization reaction in a Parr reactor at 80° C. with 345 mL of MeOH, 198 g of crude C4 (49.4 wt % butadiene, with the remainder being primarily butanes and butenes), 8.4 mL of the NaOMe stock solution, 15.6 mL of heptane, 12.6 mL of a solution of diethylhydroxamic acid (DEHA) in MeOH (0.021 M), and 2.1 mL of the catalyst. Observe that the catalyst shows no solids precipitation after storing for more than 4 weeks.

EXAMPLE 6

(20) Use the catalyst composition of Example 5 in a butadiene telomerization at 80° C. Conversion of butadiene versus time is shown below in Table 3.

(21) TABLE-US-00003 TABLE 3 Telomerization in a Parr reactor at 80° C. Pd:TMTPA-di-OMe = 1:1.3. Conversion of Selectivity Yield Time (min) butadiene (%) MOD-1 (%) MOD-1 (%) 5 36.1 90.9 32.8 30 62.3 92.4 57.6 60 82.0 92.3 75.7 90 90.1 92.5 83.3 120 93.4 92.5 86.4 150 95.2 92.5 88.1

EXAMPLE 7

(22) 1:1.2 equivalents ratio, Pd to TMTPA-di-OMe.

(23) Prepare the catalyst as in Example 1, but with 0.0768 g (0.00020 mol) TMTPA-di-OMe, 0.0510 g Pd(acac).sub.2 (0.00017 mol), 9.1 μL acetic acid (0.00017 mol), 2.148 g 1-methoxy-2,7-octadiene, and 6.315 g methanol. Observe that the catalyst shows no solids precipitation after storing for more than 4 weeks at 40° C.

EXAMPLE 8

(24) Use the catalyst of Example 7 for a telomerization reaction at 60° C. Conversion versus time is shown in Table 4.

(25) TABLE-US-00004 TABLE 4 Telomerization reaction run in duplicate at 60° C. Pd:TMTPA-di-OMe = 1:1.2. Conversion of Selectivity Yield Time (min) butadiene (%) MOD-1 (%) MOD-1 (%) 30 45.7/37.6 96.0/95.7 43.9/36.0 60 57.1/58.0 95.5/95.6 54.5/55.4 120 69.5/74.6 95.4/95.4 66.3/71.2 240 80.7/84.0 95.3/95.3 76.9/80.1

Comparative Example A

(26) 1:1.4 equivalents ratio, Pd to TMTPA-di-OMe.

(27) Prepare the catalyst as in Example 1, but with 0.0307 g (0.000086 mol) TMTPA-di-OMe. After 1 week of catalyst storage, observe the precipitation of a white solid, showing that this equivalents ratio produces an unstable product.

Comparative Example B

(28) 1:2 equivalents ratio, Pd to TMTPA-OMe.

(29) Prepare a comparative catalyst using a different but similar oxaphosphaadamantane for the catalyst, i.e., 1,3,5,7-tetramethyl-6-(2-methoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane (TMTPA-OMe), instead of the 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phos-phaadamantane (TMTPA-di-OMe) which is used to form the inventive catalyst. The TMTPA-OMe ligand may be represented schematically as structure (VI):

(30) ##STR00003##

(31) To accomplish this, dissolve Pd(acac).sub.2 (0.7100 g, 0.0024 mol), TMTPA-OMe (1.5000 g, 0.0047 mol), 70% acetic acid in water (0.1410 g, 0.0024 mol), and MOD-1 (19.990 g, 0.1426 mol) in MeOH (60.000 g, 76.00 mL). Stir this catalyst solution for more than 3 days. Observe the precipitation of a white solid.

Comparative Example C

(32) 1:1 equivalents ratio, Pd to TMTPA-OMe.

(33) Prepare another comparative catalyst by dissolving Pd(acac).sub.2 (0.7100 g, 0.0024 mol), TMTPA-OMe (0.7500 g, 0.0024 mol), 70% acetic acid in water (0.1410 g, 0.0024 mol), and MOD-1 (19.990 g, 0.1426 mol) in MeOH (60.000 g, 76.00 mL). Stir this catalyst for more than 3 days. Observe the precipitation of a black solid.

Comparative Example D

(34) 1:1.4 equivalents ratio, Pd to TMTPA-OMe.

(35) In a glovebox, dissolve 94 mL methanol (MeOH), 29 mL 1-methoxy-2,7-octadiene (MOD-1), and 91 μL acetic acid (AcOH) to prepare a stock solution that is 25 wt % MOD-1 and 75 wt % methanol.

(36) Dissolve palladium(II) acetylacetonate (Pd(acac).sub.2) (0.0196 g, 0.000064 mol), 1,3,5,7-tetramethyl-6-(2-methoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane (TMTPA-OMe) (0.0291 g, 0.000090 mol) and 5 mL of the stock solution that is 25 wt % in MOD-1, as described in Comparative Example C, to form a catalyst. Allow the catalyst to stir for 3 days at 20° C. Observe the precipitation of black solids.

Comparative Example E

(37) 1:1.8 equivalents ratio, Pd to TMPTA-OMe.

(38) Repeat the pre-catalyst preparation as described in Comparative Example D, but increase the amount of TMPTA-OMe (0.0374 g, 0.000118 mol). Observe the precipitation of white solids.

(39) The above examples and comparative examples illustrate the improved storage stability of the inventive compositions in comparison with compositions comprising a complex having either a different but similar ligand (a 1,3,5,7-tetramethyl-6-(2-methoxyphenyl)-2,4,8-trioxa-6-phospha-adamantane (TMTPA-OMe) ligand instead of a 1,3,5,7-tetramethyl-6-(2,4-di-methoxphenyl)-2,4,8-trioxa-6-phosphaadamantane (TMTPA-di-OMe) ligand, which differ from one another only in the presence or absence of a single methoxy group on the phenyl group), or in comparison with compositions comprising the same ligand but at a Pd to TMTPA-di-OMe equivalents ratio that is outside of the greater than 1:1 to 1:1.3 range that produces a storage-stable and more soluble product. In each of these comparisons, visibly discernible precipitate is encountered in the comparative's performance, either immediately or upon standing for a relatively short period of time, as specified, and therefore telomerization is not attempted therewith. In sharp contrast, telomerizations carried out using the inventive catalyst compositions are very successful.