Catalyst composition for reduction of polymer formation in ethylene dimerization

Abstract

To provide a catalyst composition for reduction of polymer formation in ethylene dimerization.SOLUTION: A catalyst composition comprises a bio-based modifier as a polymer suppressant, a titanate compound, an alkyl aluminum compound, and an organic ether. The bio-based polymer suppressant is a compound selected from the group consisting of an isohexide-derived ether compound of formula I, an isomer of formula I, or a combination thereof, wherein R1 and R2 are independently selected from the group consisting of CH3, C2H5, n-C3H7, i-C3H7, n-C4H9, i-C4H9, Ph, C1 to C8 alkyl groups, an aryl group, and a heteroaryl group, or a combination thereof.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a catalyst composition for the reduction of polymer formation comprising a bio-based modifier as a polymer inhibitor for ethylene dimerization, a titanate compound, an alkylaluminum compound, and an organic ether. [Background technology]

[0002] The ethylene dimerization process leading to the production of 1-butene is economically important, especially when high purity levels of 1-butene are required. As the primary component of linear 1-alkenes, 1-butene serves as a versatile chemical intermediate that plays an important role in the production of a diverse range of industrial products. Furthermore, its diverse applications enhance its importance in various industries. (1. McGuinness DS. Olefin oligomerization via metallacycles: Dimerization, trimerization, tetramerization, and beyond. Chem Rev 2011;111:2321-2341. 2. Vogt D. Applied homogeneous catalysis with organometallic compounds. In: Cornils B, Herrmann WA, editors. Vol. 1, Weinheim: Wiley-VCH Inc; 2002, p. 245). Typically, the ethylene dimerization process occurs in the liquid phase using a homogeneous catalyst system, such as Ti(OC4H9)4-Al(C2H5)3, along with an electron donor. Triethylaluminum (TEA), represented as Al(C2H5)3, functions as an activator in this system, facilitating the release of free coordination sites within the titanate complex, where one or more Ti-C bonds are formed by replacing the ethyl groups with the butoxide groups of the titanate complex. Catalyst modifiers are electron donor ligands, acting as Lewis bases or polar organic compounds. When introduced into the catalyst system, they enhance the selectivity for the desired reaction. (Al-Sadoun AW. Dimerization of ethylene to 1-butene catalyzed by Ti(OR')4-AlR3.Appl Catal A 1993;105:1-40.Al-Jaralleh AM,Anabtawi JA,Siddiqui MAB,Aitani AM,Al-Sadoun AW.Ethylene dimerization and oligomerization to 1-butene and linear alpha-olefins:A review of catalytic system and processes.Catal.Today 1992;14:1-121).

[0003] In the 1970s, the Institute of Problems of Chemical Physics (USSR Academy of Sciences), in collaboration with various industrial institutions, pioneered the ethylene dimerization process to produce 1-butene, marking the beginning of the first selective method for ethylene oligomerization. This development led to the establishment of two industrial plants dedicated to 1-butene production in the early 1980s (SS Ivanchev, V. I. Zhukov, G.P. Belov, et al., Plast. Massy, ​​No. 10, 82 (1990)).

[0004] WO 2017 / 120310 discloses a catalyst system for reducing polymer fouling in olefin oligomerization, particularly the specific dimerization of ethylene to 1-butene, comprising at least one titanate compound, at least one aluminum compound, and one antifouling agent.

[0005] WO 2019 / 060299 discloses a process for selectively producing 1-butene, which comprises, in a first step, combining at least one antifouling agent and at least one alkylaluminum compound to form at least one antifouling agent, and, in a second step, supplying the antifouling feed stream, a catalyst comprising at least one titanate compound, and ethylene into a reactor.

[0006] U.S. Patent No. 11,786,889 discloses a catalyst system capable of reducing polymer fouling, which may include at least one titanate compound, at least one aluminum compound, and an antifouling agent. The antifouling agent may be selected from one or more of phosphonium or phosphonium salts, sulfonates or sulfonate salts, sulfonium or sulfonium salts, esters containing cyclic moieties, anhydrides, polyethers, and long-chain amine-capped compounds. The catalyst system may further include a non-polymeric ether compound.

[0007] There remains a need for catalyst development that addresses the challenges associated with polymer formation during oligomerization reactions. Oligomerization systems face recognized problems associated with polymer creation. Long residence times and insufficient heat dissipation from the highly exothermic reaction result in the production of residues primarily composed of polyethylene. Persistent fouling leads to more frequent interruptions in the process and increased maintenance costs for the removal of deposited polymer residues. These polymer residues can accumulate layer by layer, thereby blocking openings and ports in areas where fluids move. Furthermore, polymer coatings on reactor walls can act as insulation, impeding heat transfer within the reactor. The polymers produced can also negatively impact the reaction process by acting as contaminants.

[0008] Thus, the present disclosure reduces plant operational downtime by overcoming the polymer formation problem through the use of novel catalyst components. Summary of the Invention [Problem to be solved by the invention]

[0009] The primary objective of this disclosure is to develop the design and synthesis of a catalyst composition for the selective dimerization of ethylene.

[0010] Another object of the present disclosure is to develop the synthesis and characterization of isohexide-based modifiers as polymer inhibitors for ethylene dimerization.

[0011] Another object of the present disclosure is to develop bio-based modifiers as polymer inhibitors for ethylene dimerization.

[0012] A further object of the present disclosure is to reduce plant operational downtime by overcoming polymer formation problems through the use of novel catalyst components.

[0013] Another object of the present disclosure is to provide a process for the synthesis of bio-based modifiers as polymer inhibitors for ethylene dimerization.

[0014] It is yet another object of the present disclosure to provide a catalyst composition that maintains relatively high dimerization activity while reducing polymer formation.

[0015] Another object of the present disclosure is to provide a process for producing 1-butene with high selectivity and conversion using a catalyst composition for reduced polymer formation. [Means for solving the problem]

[0016] The present disclosure provides: a) titanium alkoxide compounds, b) alkylaluminum compounds, c) organic ethers, and d) Bio-based polymer inhibitors The present invention relates to a catalyst composition for the reduction of polymer formation, comprising:

[0017] The present disclosure provides a process for the synthesis of bio-based modifiers as polymer inhibitors for ethylene dimerization.

[0018] In another aspect of the present disclosure, there is provided a process for producing 1-butene with high selectivity and conversion using a catalyst composition for reducing polymer formation comprising a titanium alkoxide compound, an alkyl aluminum compound, an organic ether, and a bio-based polymer inhibitor, wherein the titanium alkoxide compound, alkyl aluminum compound, organic ether, and bio-based polymer inhibitor are present in a molar ratio ranging from 1:2 to 10:0.1 to 1:1 to 500.

[0019] These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description. This Summary is provided to introduce a selection of concepts in a simplified form. It is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. DETAILED DESCRIPTION OF THE INVENTION

[0020] The foregoing objects of the present disclosure are achieved and the problems and drawbacks associated with prior art techniques, approaches and methods are overcome by the present disclosure as described below in preferred embodiments.

[0021] The present disclosure provides: a) titanium alkoxide compounds, b) alkylaluminum compounds, c) organic ethers, and d) Bio-based polymer inhibitors The present invention provides a catalyst composition for the reduction of polymer formation, comprising:

[0022] The present disclosure provides a catalyst composition in which a titanium alkoxide compound is present in a molar ratio to an alkylaluminum compound in the range of 1:2-10, a titanium alkoxide compound is present in a molar ratio to an organic ether in the range of 1:0.1-1, and a titanium alkoxide compound is present in a molar ratio to a bio-based polymer inhibitor in the range of 1:1-500.

[0023] The titanium alkoxide compound is selected from the group consisting of titanium(IV) methoxide, Ti(OMe)4, titanium(IV) ethoxide, Ti(OEt)4, titanium(IV) i-propoxide Ti(i-OPr)4, titanium(IV) butoxide, and Ti(OBu)4, or a combination thereof. The alkylaluminum compound is selected from the group consisting of triethylaluminum (TEAL), triisobutylaluminum (TIBA), triisopropylaluminum (TIPRA), tri-n-hexylaluminum (TnHA), and diethylaluminum chloride (DEAC), or a combination thereof. The organic ether is selected from the group consisting of tetrahydrofuran, tetrahydropyran, 1,4-dioxane, and 18-crown-6 ether, or a combination thereof.

[0024] The bio-based polymer inhibitor is a compound selected from the group consisting of an isohexide-derived ether compound of Formula I, an isomer of Formula I, or a combination thereof.

[0025] [ka]

[0026] wherein R1 and R2 are independently selected from the group consisting of CH3, C2H5, n-C3H7, i-C3H7, n-C4H9, i-C4H9, Ph, a C1-C8 alkyl group, an aryl group, and a heteroaryl group, or a combination thereof.

[0027] The synthesized modifiers are biobased, prepared from isohexides derived from sorbitol. Isohexide-based ether moieties have not been reported as polymer inhibitors for ethylene oligomerization, particularly in the ethylene dimerization to 1-butene process. Subsequent diethers of isohexides contain ether moieties. Modifications of the molecules and synthetic approaches outlined in this disclosure are straightforward to implement. The methods provided in this disclosure utilize these isohexide derivatives as polymer inhibitor components in the dimerization of ethylene to 1-butene.

[0028] Panel 1 shows the structure of a proposed bio-based modifier as a catalyst component claimed in this disclosure.

[0029] [ka]

[0030] Chemicals used in the synthesis of the catalyst compositions as described in this disclosure include isosorbide, sodium hydride (NaH), DCM, water, alkyl / aryl halides such as methyl iodide, ethyl iodide, titanium alkoxides such as titanium(IV) methoxide, Ti(OMe)4, titanium(IV) ethoxide, Ti(OEt)4, titanium(IV) i-propoxide Ti(i-OPr)4, titanium(IV) butoxide Ti(OBu)4, hexane, toluene, heptane, methanol, hydrochloric acid, ethylene gas, alkyl aluminum such as triethyl aluminum (TEAL), triisobutyl aluminum. (TIBA), triisopropyl aluminum (TIPRA), and diethyl aluminum chloride (DEAC).

[0031] All reactions were carried out using standard Schlenk techniques and a glovebox. Chemicals used for catalyst preparation were stored in an argon-atmosphere glovebox. Dimerization reactions were carried out using a high-pressure reactor. Hexane, heptane, toluene, and cyclohexane were distilled in a sodium benzophenone system, and freshly distilled solvents were used in the experiments.

[0032] The present disclosure further provides a process for producing 1-butene with high selectivity and conversion using a catalyst composition for reducing polymer formation, comprising a titanium alkoxide compound, an alkyl aluminum compound, an organic ether, and a bio-based polymer inhibitor, wherein the titanium alkoxide compound, the alkyl aluminum compound, the organic ether, and the bio-based polymer inhibitor are present in a molar ratio ranging from 1:2 to 10:0.1 to 1:1 to 500.

[0033] The synthesized biobased polymeric inhibitors were characterized using the following techniques. a) Fourier transform infrared spectroscopy (FTIR): FTIR spectra were recorded on a Perkin Elmer Spectrum GX instrument (Waltham, MA, USA). Samples were scanned in the scanning range of 4000–400 cm at a resolution of 2 cm. b) NMR analysis: 1H and 13C-NMR spectra were recorded on a Bruker Avance 500 MHz spectrometer. Deuterated solvents for NMR experiments were obtained from Aldrich Chemical Co. c) Gas Chromatography: Gas samples were analyzed by using a Perkin Elmer Clarus 690 with a premium alumina column of 0.53 mm ID and 30 meters long. For liquid samples, GC-VUV, Rxi-1ms column of 0.25 mm ID and 30 meters long.

[0034] Synthesis of modifiers for polymer inhibitors Synthesis Protocol: In a clean 250 mL Schlenk RBF, NaH (2.05 g, 0.0855 mol) was obtained. To this, 100 mL of THF and 1 equivalent of isosorbide were added, and the RB temperature was adjusted to 0-5°C. At the same temperature, 2 equivalents of alkyl / aryl halide were added. Upon completion of the addition, the reaction mixture was stirred for 12-24 hours, treated with ice water, and extracted with DCM. The yield of the desired polymer inhibitor obtained was greater than 90%.

[0035] As shown in panel 2, 1 H, 13 C-NMR and FTIR analysis were used to characterize the resulting molecules.

[0036] [ka] [Example]

[0037] The present disclosure is further illustrated by reference to the following examples, which are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. These examples are not intended to be inclusive of all aspects of the subject matter disclosed herein, but rather to illustrate representative features, methods, compositions, and results. These examples are not intended to exclude equivalents and variations of the present disclosure that would be apparent to one of ordinary skill in the art.

[0038] Example I: Oligomerization experiments were conducted in a 1 L high-pressure reactor. Prior to the experimental run, the reactor underwent an inertization process, which involved evacuating the reactor with a vacuum pump and heating to 160°C. After reaching a stable temperature, the reactor was pressurized to 4 bar with nitrogen. Three minutes after the start of pressurization, the gas outlet valve was opened to release and vent the nitrogen. Two minutes after the start of gas release, the valve from the main exhaust line to the vacuum pump was opened to evacuate the reactor. The reactor was evacuated for 15 minutes. The gas outlet valve was then closed, and the reactor was repressurized with nitrogen. This pump-pressurization cycle was carried out for at least 2-3 hours. The reactor was then evacuated with vacuum for another 2-3 hours. During the final hour, the reactor was cooled to 40°C. The reactor was then pressurized to 1-3 bar until the reaction started.

[0039] Stock solutions containing the components of the catalyst mixture were prepared. Two stock solutions were prepared in a glove box. Heptane was used as the solvent. The reactor was filled with 80% heptane. The first solution contained the polymer inhibitor and TEAL cocatalyst mixed with 10% heptane. The second solution contained titanium tetrabutoxide catalyst, THF, and 10% heptane. The first and second solutions were each placed in the reactor under a positive ethylene flow. The reactor was then set to the desired pressure. The temperature in the reactor was increased and set to a target value of 55°C. After the start of ethene dosing, the reaction was run for 30 minutes. After the 30-minute reaction time, the reaction was terminated by injecting 1 mL of methanol. The reactor was depressurized and the temperature was set to 25°C.

[0040] The reactor residue was then washed with 10 wt % aqueous hydrochloric acid to dissolve any catalyst residues, and the remaining solid polymer was filtered, dried in an oven at 110° C. overnight, and weighed.

[0041] Example II: To evaluate the polymer inhibition effect of the catalyst composition as described in this disclosure, ethylene oligomerization reactions were carried out and evaluated. A control sample that did not have a polymer inhibitor is shown as "Comparative Example" in Table 1. For the experiment, titanium tetrabutoxide (see Table 2) was used. A catalyst mixture containing triethylaluminum (referred to as "Ti" in Table 2), THF, triethylaluminum (referred to as "TEAL" in Table 2), and a polymer inhibitor (referred to as "PS" in Table 2) was used. The concentrated PS is shown in Table 1. The molar ratio of Ti:THF:TEAL in the examples was 1:0.8:8.

[0042] Comparative Example 1: All parameters were the same, except for the catalyst composition as Ti / TEAL / THF in a molar ratio of 1:0.8:8 and a pressure of 23.5 bar, following the process for oligomerization outlined in Example I. The values ​​for 1-butene selectivity for the reaction with the catalyst composition of Comparative Example 1 are shown in Table 1.

[0043] Example 1: The process for oligomerization outlined in Example I was followed, with all parameters remaining the same, except for the catalyst composition as Ti / TEAL / THF / PS-1 and a pressure of 23.5 bar. The molar ratio of the catalyst composition Ti:THF:TEAL was 1:0.8:8. The polymer inhibitor PS-1 was present at a concentration of 1500 ppm and was 1,4:3,6-dianhydro-2,5-di-O-methyl-D-glucitol. Table 1 shows experimental data for ethylene dimerization to 1-butene, including 1-butene selectivity.

[0044] Example 2: The process for oligomerization outlined in Example I was followed, with all parameters remaining the same, except for the catalyst composition as Ti / TEAL / THF / PS-2 and a pressure of 23.5 bar. The polymer inhibitor PS-2, present at a concentration of 1500 ppm, is 1,4:3,6-dianhydro-2,5-di-O-ethyl-D-glucitol. Experimental data for ethylene dimerization to 1-butene, including 1-butene selectivity, are provided in Table 1.

[0045] Example 3: The process for oligomerization outlined in Example I is carried out with the catalyst composition Ti / TEAL / THF / PS-3, with all parameters remaining the same except for a pressure of 23.5 bar. The polymer inhibitor PS-3 is present at a concentration of 1500 ppm and is 1,4:3,6-dianhydro-2,5-di-O-isopropyl-D-glucitol. Table 1 shows experimental data for ethylene dimerization to 1-butene, including 1-butene selectivity.

[0046] Comparative Example 2: All parameters in this example are the same as those described in Comparative Example 1, except that the process for oligomerization is carried out at a pressure of 12.5 bar. Table 2 shows the dimerization activity and polymer loss (%) for the reaction for the catalyst composition described in Comparative Example 2.

[0047] Example 4: All parameters in this example are the same as those described in Example 1, except that the process for oligomerization is carried out at a pressure of 12.5 bar. Table 2 shows the dimerization activity and polymer loss (%) for the reaction for the catalyst composition described in Example 4.

[0048] Example 5: All parameters in this example are the same as those described in Example 2, except that the process for oligomerization was carried out at a pressure of 12.5 bar. Table 2 shows the dimerization activity and polymer loss (%) for the reaction for the catalyst composition described in Example 5. is shown.

[0049] Example 6: All parameters in this example are the same as those described in Example 3, except that the process for oligomerization is carried out at a pressure of 12.5 bar. Table 2 shows the dimerization activity and polymer loss (%) for the reaction for the catalyst composition described in Example 6.

[0050] The conversion and 1-butene selectivity for reactions utilizing each of the sample catalyst compositions are shown in Table 1. It is clear from Table 1 that the conversion, 1-butene yield, and selectivity increase with the addition of the polymer inhibitor. The reaction conditions for ethylene dimerization to 1-butene for the data reported in Table 1 are as follows: Catalyst concentration=200mg; Temperature=50~60℃; Time=0.5 hours, PS concentration=1500ppm; Pressure: Comparative Example 1 = 23.5 bar and Comparative Example 2 = 12.5 bar. Pressure: Example 1 = 23.5 bar and Example 2 = 12.5 bar.

[0051] [Table 1]

[0052] Example III The dimerization activity and polymer reduction (%) for reactions utilizing each of the sample catalysts are shown in Table 2. As evidenced by the reaction data in Table 2, the addition of the polymer inhibitor reduced polymer formation to some extent while maintaining relatively high dimerization activity.

[0053] For the experiments, a catalyst mixture containing titanium tetrabutoxide (shown as "Ti" in Table 2), THF, triethylaluminum (shown as "TEAL" in Table 2), and a polymer inhibitor (shown as "PS" in Table 2) was used. The enriched PS is shown in Table 1. The molar ratio of Ti:THF:TEAL in the examples was 1:0.8:8.

[0054] [Table 2]

[0055] The reaction conditions for dimerization activity and polymer loss (%) for the oligomerization reaction for the data reported in Table 2 are as follows: Temperature = 50-60°C; Time = 0.5 hours; PS concentration=1500ppm PS-1: 1,4:3,6-dianhydro-2,5-di-O-methyl-D-glucitol PS-2: 1,4:3,6-dianhydro-2,5-di-O-ethyl-D-glucitol PS-3: 1,4:3,6-dianhydro-2,5-di-O-isopropyl-D-glucitol

[0056] advantage: 1. The present disclosure provides a catalyst composition for the reduction of polymer formation. 2. The present disclosure provides a catalyst composition that exhibits high selectivity and conversion for producing 1-butene from ethylene dimerization reactions. 3. The present disclosure provides bio-based modifiers as polymer inhibitors, thus providing environmentally friendly catalyst compositions.

[0057] Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible, and therefore, the spirit and scope of the subject matter should not be limited to the description of the preferred embodiments contained therein.

Claims

1. a) titanium alkoxide compounds, b) alkylaluminum compounds; c) an organic ether, and d) Bio-based polymer inhibitors 1. A catalyst composition for the reduction of polymer formation in ethylene dimerization, comprising:

2. 2. The catalyst of claim 1, wherein the titanium alkoxide compound is present in a molar ratio in the range of 1:2 to 10 relative to the alkylaluminum compound.

3. 2. The catalyst of claim 1, wherein the titanium alkoxide compound is present in a molar ratio to the organic ether in the range of 1:0.1 to 1.

4. 10. The catalyst of claim 1, wherein the titanium alkoxide compound is present in a molar ratio to the bio-based polymer inhibitor in the range of 1:1-500.

5. The titanium alkoxide compound is titanium (IV) methoxide, Ti(OMe) ４ , titanium(IV) ethoxide, Ti(OEt) ４ , titanium (IV) i-propoxide Ti(i-OPr) ４ , titanium(IV) butoxide, Ti(OBu) ４ or a combination thereof.

6. 2. The catalyst of claim 1, wherein the alkyl aluminum compound is selected from the group of alkyl aluminum compounds consisting of triethyl aluminum (TEAL), triisobutyl aluminum (TIBA), triisopropyl aluminum (TIPRA), tri-n-hexyl aluminum (TnHA), and diethyl aluminum chloride (DEAC), or a combination thereof.

7. 2. The catalyst of claim 1, wherein the organic ether is selected from the group consisting of tetrahydrofuran, tetrahydropyran, 1,4-dioxane, and 18-crown-6-ether, or a combination thereof.

8. The biobased polymer inhibitor is represented by Formula I 【Chemical 1】 (In the formula, R １ and R ２ is CH ３ , C ２ H ５ , n-C ３ H ７ , i-C ３ H ７ , n-C ４ H ９ , i-C ４ H ９ , Ph, C1-C8 alkyl groups, aryl groups and heteroaryl groups or combinations thereof) and isomers of formula I or combinations thereof.

2. The catalyst of claim 1, wherein the compound is selected from:

9. A process for producing 1-butene with high selectivity and conversion from a catalyst composition for the reduction of polymer formation comprising a titanium alkoxide compound, an alkylaluminum compound, an organic ether, and a bio-based polymer inhibitor.

10. 10. The process of claim 9, wherein the catalyst composition for the reduction of polymer formation in ethylene dimerization comprises the titanium alkoxide compound, the alkyl aluminum compound, the organic ether, and the bio-based polymer inhibitor present in a molar ratio ranging from 1:2 to 10:0.1 to 1:1 to 500.

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