Catalyst composition for reducing 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 reducing 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 Art

[0002] The ethylene dimerization process leading to the production of 1-butene is of economic importance, particularly when high-purity 1-butene is required. As a primary component of linear 1-alkenes, 1-butene acts as a versatile chemical intermediate, playing a crucial role in the production of a wide range of industrial products. Furthermore, its importance in various industries is enhanced by its diverse applications. (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 catalytic system such as Ti(OC4H9)4-Al(C2H5)3 along with an electron donor. Triethylaluminum (TEA), represented as Al(C2H5)3, acts as the activator in this system. This facilitates the release of free coordination sites within the titanate complex, forming one or more Ti-C bonds by substituting its ethyl group with the butoxide group of the titanate complex. Catalytic modifiers are electron donor ligands and act as Lewis bases or polar organic compounds. When introduced into the catalytic 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 (USA Academy of Sciences), in collaboration with various industrial institutions, pioneered an ethylene dimerization process to produce 1-butene. This marked the beginning of the first selective method for ethylene oligomerization. The progress of this development led to the establishment of two industrial plants specializing in 1-butene production in the early 1980s. (SSIvanchev, VIZhukov, GPBelov, et al., Plast. Massy, ​​No. 10, 82 (1990)).

[0004] International Publication No. 2017 / 120310 discloses a catalyst system comprising at least one titanate compound, at least one aluminum compound, and one antifouling agent for reducing polymer fouling in olefin oligomerization, particularly in the specific dimerization of ethylene to 1-butene.

[0005] International Publication No. 2019 / 060299 discloses a process for selectively producing 1-butene, comprising, in a first step, combining at least one antifouling agent and at least one alkylaluminum compound to form at least one antifouling agent. The process further comprises, in a second step, supplying a supply stream of antifouling agents, a catalyst comprising at least one titanate compound, and ethylene into a reactor.

[0006] U.S. Patent No. 11786889 discloses a catalyst system capable of reducing polymer fouling, which may comprise at least one titanate compound, at least one aluminum compound, and an antifouling agent. The antifouling agent may be selected from one or more 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 comprise a non-polymer ether compound.

[0007] The need for catalyst development to address the challenges associated with polymer formation during oligomerization reactions remains. Oligomerization systems face recognized problems associated with polymer creation. Prolonged retention and insufficient heat dissipation from strong exothermic reactions lead to the formation of residues primarily composed of polyethylene. Persistent fouling leads to more frequent process interruptions and increased maintenance costs for removing adhering polymer residues. These polymer residues can accumulate layer by layer, thereby potentially clogging openings and ports within areas where fluids move. Furthermore, polymer coatings on reactor walls can act as insulators, hindering heat transfer within the reactor. The resulting polymers can also negatively impact the reaction process by acting as contaminants.

[0008] Therefore, this disclosure reduces plant operational downtime by overcoming polymer formation problems through the use of novel catalyst components. [Overview of the project] [Problems that the invention aims to solve]

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

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

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

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

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

[0014] Another object of this disclosure is to provide a catalyst composition that maintains relatively high dimerization activity while reducing polymer formation.

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

[0016] This disclosure is, a) Titanium alkoxide compounds, b) Alkylaluminum compounds, c) Organic ethers, and d) Biopolymer inhibitors This invention relates to a catalyst composition for reducing polymer formation, including the following:

[0017] This 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, a process for producing 1-butene with high selectivity and conversion rate is provided by using a catalyst composition for reducing polymer formation, which comprises 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 in the range of 1:2 to 10:0.1 to 1:1 to 500.

[0019] These and other features, aspects, and advantages of the 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. This summary is not intended to identify key features or essential features of the subject matter claimed, nor is it intended to be used to limit the scope of the subject matter claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

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

[0021] The present disclosure provides a) a titanium alkoxide compound, b) an alkyl aluminum compound, c) an organic ether, and d) a bio-based polymer inhibitor for a catalyst composition for reducing polymer formation.

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

[0023] Titanium alkoxide compounds are 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 combinations thereof. Alkylaluminum compounds are selected from the group consisting of triethylaluminum (TEAL), triisobutylaluminum (TIBA), triisopropylaluminum (TIPRA), tri-n-hexylaluminum (TnHA), and diethylaluminum chloride (DEAC), or combinations thereof. Organic ethers are selected from the group consisting of tetrahydrofuran, tetrahydropyran, 1,4-dioxane, and 18-crown-6-ether, or combinations thereof.

[0024] The biopolymer inhibitor is a compound selected from the group consisting of isohexide-derived ether compounds of formula I, isomers of formula I, or combinations thereof.

[0025] [ka]

[0026] In the formula, R1 and R2 are independently selected from the group consisting of CH3, C2H5, n-C3H7, i-C3H7, n-C4H9, i-C4H9, Ph, C1-C8 alkyl groups, aryl groups, and heteroaryl groups, or combinations thereof.

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

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

[0029] [ka]

[0030] Chemicals used in the synthesis of catalyst compositions as described in this disclosure include isosorbide, sodium hydride (NaH), DCM, water, alkyl / aryl halides such as methyl iodide and 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, and alkylaluminum such as triethylaluminum (TEAL) and triisobutylaluminum. Examples include (TIBA), triisopropylaluminum (TIPRA), and diethylaluminum chloride (DEAC).

[0031] All reactions were carried out using the standard Schlenk process and a glove box. Chemicals used for catalyst preparation were stored in a glove box under an argon atmosphere. The dimerization reaction was carried out using a high-pressure reactor. Hexane, heptane, toluene, and cyclohexane were distilled in a sodium benzophenone system, and the freshly distilled solvents were used in the experiments.

[0032] Furthermore, the present disclosure provides a process for producing 1-butene with high selectivity and conversion rate using a catalyst composition for reducing polymer formation, comprising a titanium alkoxide compound, an alkylaluminum compound, an organic ether, and a biopolymer inhibitor, wherein the titanium alkoxide compound, alkylaluminum compound, organic ether, and biopolymer inhibitor are present in molar ratios ranging from 1:2 to 10:0.1 to 1:1 to 500.

[0033] The synthesized biopolymer inhibitors were characterized using the following techniques. a) Fourier transform infrared spectroscopy (FTIR): FTIR spectra were recorded using the Perkin Elmer Spectrum GX instrument (Waltham, Massachusetts, USA). The sample was scanned at a resolution of 2 cm⁻¹ with a scanning range of 4000–400 cm⁻¹. b) NMR analysis: 1H and 13C-NMR spectra were recorded using a Bruker Avance 500 MHz spectrometer. The deuterated solvent for the NMR experiment was obtained from Aldrich Chemical Co. c) Gas chromatography: Gas samples were analyzed using a Perkin Elmer Clarus 690 column with a high-quality alumina column having an ID of 0.53 mm and a length of 30 m. Liquid samples were analyzed using a GC-VUV Rxi-1ms column with a length of 30 m and an ID of 0.25 mm.

[0034] Synthesis of modifiers for polymer inhibitors Synthesis protocol: NaH (2.05 g, 0.0855 mol) was obtained in 250 mL of clean Schlenk RBF. 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 halides were added. After the addition was completed, the reaction mixture was stirred for 12-24 hours. The mixture was treated with ice water and extracted with DCM. The yield of the desired polymer inhibitor obtained was over 90%.

[0035] As shown in Panel 2, 1 H, 13 The obtained molecules were identified using 1C-NMR and FTIR analysis.

[0036] [ka] [Examples]

[0037] This 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 this disclosure in any way. These examples are not intended to include 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 this disclosure that would be obvious to those skilled in the art.

[0038] Example I: An oligomerization experiment was conducted in a 1 L high-pressure reactor. Before the experimental procedure, the reactor underwent an inactivation process, which included evacuating the reactor with a vacuum pump and heating it 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 nitrogen and evacuate the reactor. Two minutes after the start of gas release, the valve from the main exhaust pipe 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 pressurized again with nitrogen. The pump pressurization cycle was run for at least 2-3 hours. The reactor was then evacuated under vacuum for a further 2-3 hours. The reactor was cooled to 40°C for the last hour. The reactor was then pressurized to 1-3 bar until the reaction began.

[0039] A storage solution containing the components of the catalyst mixture was prepared. Two storage solutions were prepared in a glove box. Heptane was used as the solvent. The reactor was filled with 80% heptane. The first solution contained a polymer inhibitor and a TEAL co-catalyst mixed with 10% heptane. The second solution contained a titanium tetrabutoxide catalyst, THF, and was mixed with 10% heptane. The first and second solutions were each introduced into the reactor under a positive ethylene flow. The reactor was then set to the desired pressure. The temperature inside the reactor rose and was set to the target value of 55°C. After the start of ethene application, the reaction was carried out for 30 minutes. After the 30-minute reaction time, the reaction was terminated by injecting 1 mL of methanol. The pressure was released from the reactor and the temperature was set to 25°C.

[0040] Next, the residue in the reactor was washed with a 10% by weight hydrochloric acid aqueous solution to dissolve all catalyst residue. The remaining solid polymer was filtered, dried overnight in an oven at 110°C, and weighed.

[0041] Example II: To evaluate the polymer-inhibiting effect of the catalyst composition described herein, an ethylene oligomerization reaction was performed and evaluated. A control sample without 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: Following the oligomerization process outlined in Example I, all parameters were the same except for the catalyst composition as Ti / TEAL / THF in a molar ratio of 1:0.8:8 and the pressure of 23.5 bar. 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: Following the oligomerization process outlined in Example I, all parameters were the same except for the catalyst composition as Ti / TEAL / THF / PS-1, with a pressure of 23.5 bar. The molar ratio Ti:THF:TEAL of the catalyst composition 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 the 1-butene selectivity.

[0044] Example 2: Following the oligomerization process outlined in Example I, all parameters were the same except for the catalyst composition as Ti / TEAL / THF / PS-2, with 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 oligomerization process outlined in Example I was carried out using the catalyst composition as Ti / TEAL / THF / PS-3, with all parameters the same except for a pressure of 23.5 bar. The polymer inhibitor PS-3 was present at a concentration of 1500 ppm and was 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 oligomerization process is carried out at a pressure of 12.5 bar. Table 2 shows the dimerization activity and polymer reduction (%) 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 oligomerization process is carried out at a pressure of 12.5 bar. Table 2 shows the dimerization activity and polymer reduction (%) 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 oligomerization process is carried out at a pressure of 12.5 bar. Table 2 shows the dimerization activity and polymer reduction (%) for the reaction for the catalyst composition described in Example 5. This is shown.

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

[0050] Table 1 shows the conversion rate and the 1-butene selectivity for reactions using each of the sample catalyst compositions. It is clear from Table 1 that the conversion rate, 1-butene yield, and selectivity increase with the addition of polymer inhibitors. The reaction conditions for ethylene dimerization to 1-butene for the data listed 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 Table 2 shows the dimerization activity and polymer reduction (%) for reactions using each of the sample catalysts. As is evident from the reaction data in Table 2, the addition of polymer inhibitors maintained relatively high dimerization activity while reducing polymer formation to some extent.

[0053] For the experiment, a catalyst mixture containing titanium tetrabutoxide (indicated as "Ti" in Table 2), THF, triethylaluminum (indicated as "TEAL" in Table 2), and a polymer inhibitor (indicated 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.

[0054] [Table 2]

[0055] The reaction conditions for the dimerization activity and polymer reduction (%) for the oligomerization reaction, as shown 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. This disclosure provides catalyst compositions for reducing polymer formation. 2. This disclosure provides a catalyst composition that exhibits high selectivity and conversion rate for producing 1-butene from an ethylene dimerization reaction. 3. This disclosure provides a bio-based modifier as a polymer inhibitor, and therefore provides an environmentally friendly catalyst composition.

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

Claims

1. a) Titanium alkoxide compounds, b) Alkylaluminum compounds, c) Organic ethers, and d) Formula I 【Chemistry 1】 (In the formula, R1 and R2 are independently selected from the group consisting of C1-C8 alkyl groups, aryl groups, heteroaryl groups, or combinations thereof.) A biopolymer inhibitor which is a compound selected from the group consisting of isohexide-derived ether compounds and isomers of formula I or combinations thereof. A catalyst composition for reducing polymer formation in ethylene dimerization, comprising the titanium alkoxide compound, the alkylaluminum compound, the organic ether, and the biopolymer inhibitor present in a molar ratio in the range of 1:2:0.1:1 to 1:10:1:

500.

2. The catalyst composition according to claim 1, wherein the molar ratio of the titanium alkoxide compound and the alkylaluminum compound is in the range of 1:2 to 1:

10.

3. The molar ratio of the titanium alkoxide compound and the organic ether is in the range of 1:0.1 to 1:

1. A catalyst composition according to claim 1.

4. The catalyst composition according to claim 1, wherein the molar ratio of the titanium alkoxide compound and the biopolymer inhibitor is in the range of 1:1 to 1:

500.

5. The titanium alkoxide compound is of the formula Ti(OMe) ４ Titanium (IV) methoxide, formula Ti(OEt) ４ Titanium (IV) ethoxide, formula Ti(i-OPr) ４ Titanium(IV) i-propoxide, formula Ti(OBu) ４ The catalyst composition according to claim 1, selected from the group consisting of titanium (IV) butoxide or combinations thereof.

6. The catalyst composition according to claim 1, wherein the alkylaluminum compound is selected from the group of alkylaluminum compounds consisting of triethylaluminum (TEAL), triisobutylaluminum (TIBA), triisopropylaluminum (TIPRA), tri-n-hexylaluminum (TnHA), and diethylaluminum chloride (DEAC), or combinations thereof.

7. The catalyst composition according to 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. A process for producing 1-butene, comprising carrying out ethylene oligomerization in the presence of the catalyst composition according to any one of claims 1 to 7.

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