CN114891035B - Difunctional tetranuclear metal lithium complex and preparation method and application thereof - Google Patents
Difunctional tetranuclear metal lithium complex and preparation method and application thereof Download PDFInfo
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- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 37
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 13
- 239000002184 metal Substances 0.000 title claims abstract description 13
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 11
- 238000002360 preparation method Methods 0.000 title claims abstract description 7
- 238000010668 complexation reaction Methods 0.000 title description 2
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 63
- 229920000747 poly(lactic acid) Polymers 0.000 claims abstract description 24
- JJTUDXZGHPGLLC-UHFFFAOYSA-N lactide Chemical compound CC1OC(=O)C(C)OC1=O JJTUDXZGHPGLLC-UHFFFAOYSA-N 0.000 claims abstract description 20
- 238000000034 method Methods 0.000 claims abstract description 19
- 238000003756 stirring Methods 0.000 claims abstract description 16
- 238000006116 polymerization reaction Methods 0.000 claims abstract description 13
- 239000002904 solvent Substances 0.000 claims abstract description 7
- 230000015556 catabolic process Effects 0.000 claims abstract description 6
- 238000006731 degradation reaction Methods 0.000 claims abstract description 6
- 239000007857 degradation product Substances 0.000 claims abstract description 5
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 48
- 238000006243 chemical reaction Methods 0.000 claims description 30
- 150000004696 coordination complex Chemical class 0.000 claims description 25
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 20
- WVDDGKGOMKODPV-UHFFFAOYSA-N Benzyl alcohol Chemical compound OCC1=CC=CC=C1 WVDDGKGOMKODPV-UHFFFAOYSA-N 0.000 claims description 18
- 239000000178 monomer Substances 0.000 claims description 15
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 12
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 12
- MZRVEZGGRBJDDB-UHFFFAOYSA-N N-Butyllithium Chemical compound [Li]CCCC MZRVEZGGRBJDDB-UHFFFAOYSA-N 0.000 claims description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 239000000047 product Substances 0.000 claims description 10
- 239000013078 crystal Substances 0.000 claims description 9
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 8
- LPEKGGXMPWTOCB-UHFFFAOYSA-N 8beta-(2,3-epoxy-2-methylbutyryloxy)-14-acetoxytithifolin Natural products COC(=O)C(C)O LPEKGGXMPWTOCB-UHFFFAOYSA-N 0.000 claims description 6
- 235000019445 benzyl alcohol Nutrition 0.000 claims description 6
- ODQWQRRAPPTVAG-GZTJUZNOSA-N doxepin Chemical compound C1OC2=CC=CC=C2C(=C/CCN(C)C)/C2=CC=CC=C21 ODQWQRRAPPTVAG-GZTJUZNOSA-N 0.000 claims description 6
- 239000000706 filtrate Substances 0.000 claims description 6
- 229940057867 methyl lactate Drugs 0.000 claims description 6
- 239000002244 precipitate Substances 0.000 claims description 6
- HGHPGHVNTQSTNM-UHFFFAOYSA-N quinolin-2-ylmethanamine Chemical compound C1=CC=CC2=NC(CN)=CC=C21 HGHPGHVNTQSTNM-UHFFFAOYSA-N 0.000 claims description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 4
- 230000001588 bifunctional effect Effects 0.000 claims description 4
- 238000012691 depolymerization reaction Methods 0.000 claims description 4
- 239000003921 oil Substances 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010703 silicon Substances 0.000 claims description 4
- 238000005406 washing Methods 0.000 claims description 4
- 238000006555 catalytic reaction Methods 0.000 claims description 3
- 238000002425 crystallisation Methods 0.000 claims description 2
- 230000008025 crystallization Effects 0.000 claims description 2
- 238000001914 filtration Methods 0.000 claims description 2
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- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 2
- 238000005303 weighing Methods 0.000 claims description 2
- 239000012141 concentrate Substances 0.000 claims 1
- 239000003054 catalyst Substances 0.000 abstract description 21
- 239000000463 material Substances 0.000 abstract description 9
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- 238000002156 mixing Methods 0.000 abstract 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 10
- 150000001875 compounds Chemical class 0.000 description 7
- 238000009826 distribution Methods 0.000 description 6
- 229960000583 acetic acid Drugs 0.000 description 5
- 239000012362 glacial acetic acid Substances 0.000 description 5
- 230000005311 nuclear magnetism Effects 0.000 description 5
- 229920000642 polymer Polymers 0.000 description 5
- 239000011541 reaction mixture Substances 0.000 description 5
- 239000006228 supernatant Substances 0.000 description 5
- 238000005259 measurement Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 239000012467 final product Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
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- 229920002988 biodegradable polymer Polymers 0.000 description 1
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- 238000012937 correction Methods 0.000 description 1
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- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229920006158 high molecular weight polymer Polymers 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005297 material degradation process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 230000002085 persistent effect Effects 0.000 description 1
- 239000013502 plastic waste Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 229920001059 synthetic polymer Polymers 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
- C07F7/02—Silicon compounds
- C07F7/08—Compounds having one or more C—Si linkages
- C07F7/10—Compounds having one or more C—Si linkages containing nitrogen having a Si-N linkage
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
- B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
- B01J31/22—Organic complexes
- B01J31/2204—Organic complexes the ligands containing oxygen or sulfur as complexing atoms
- B01J31/2208—Oxygen, e.g. acetylacetonates
- B01J31/2217—At least one oxygen and one nitrogen atom present as complexing atoms in an at least bidentate or bridging ligand
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/03—Preparation of carboxylic acid esters by reacting an ester group with a hydroxy group
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
- C08G63/08—Lactones or lactides
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
- C08G63/82—Preparation processes characterised by the catalyst used
- C08G63/823—Preparation processes characterised by the catalyst used for the preparation of polylactones or polylactides
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
- C08G63/82—Preparation processes characterised by the catalyst used
- C08G63/83—Alkali metals, alkaline earth metals, beryllium, magnesium, copper, silver, gold, zinc, cadmium, mercury, manganese, or compounds thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2231/00—Catalytic reactions performed with catalysts classified in B01J31/00
- B01J2231/10—Polymerisation reactions involving at least dual use catalysts, e.g. for both oligomerisation and polymerisation
- B01J2231/14—Other (co) polymerisation, e.g. of lactides or epoxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
- B01J2531/10—Complexes comprising metals of Group I (IA or IB) as the central metal
- B01J2531/11—Lithium
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
- C07B2200/00—Indexing scheme relating to specific properties of organic compounds
- C07B2200/13—Crystalline forms, e.g. polymorphs
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2230/00—Compositions for preparing biodegradable polymers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Polyesters Or Polycarbonates (AREA)
Abstract
The invention discloses a difunctional tetranuclear metal lithium complex and a preparation method and application thereof, and belongs to the technical field of complex synthesis. The method for applying the difunctional metal lithium complex to catalyzing lactide polymerization and polylactide degradation specifically comprises the following steps: mixing and stirring lactide and a catalyst according to a proportion, and carrying out ring-opening polymerization under the protection of anhydrous and anaerobic gas to finally obtain polylactide; and adding methanol into the system, and obtaining the degradation product of the polylactide in the room temperature environment. The method has simple steps, strong controllability and low cost, can obtain the biodegradable polyester material with better performance, and can degrade the scrapped polyester material into a green solvent. The degradable plastic obtained by the invention meets the green development requirement and has wide application prospect. The characteristics of 'high controllability', 'activity' and 'multifunction' are realized in the polymerization process, and the chemical recovery of the polyester material into high-added-value chemicals can be realized at the same time, so that the recycling effect is achieved.
Description
Technical Field
The invention belongs to the technical field of complex synthesis, and particularly relates to a difunctional tetranuclear metal lithium complex, a preparation method and application thereof.
Background
Since the first commercial production of polyethylene in the 30 s of the 20 th century, many high molecular weight polymers have become an integral part of modern life, widely used in fiber polyesters, polyolefins, silicones and other engineering and rubber applications. Although these materials are widely used with their excellent mechanical properties and durability, their long degradation time has attracted global attention to increasingly serious environmental pollution due to the handling of these plastic articles. The european union has decided to prohibit or limit the use of certain consumer products containing persistent, non-degradable and toxic substances. The government of China formulated "China 21 st century agenda" states that: "walk a sustainable development way, is the self-needs and necessary choice of China's development in the future and the next century". Therefore, we are looking for more green alternatives and are concerned with the study of material degradation.
Furthermore, with the rapid consumption of fossil materials on earth, the development of alternative biodegradable polymers (preferably from sustainable sources) becomes necessary. Currently, polylactide (PLA) has become a leading place in this field due to its excellent biodegradability and biocompatibility, making it an environmentally friendly alternative to traditional petrochemical synthetic polymers. To date, the polymerization of lactide has been studied in a variety of catalysts available, including main group metal complexes, transition metals, rare earth metals, alkali/alkaline earth metals, and nonmetallic organic catalysts. PLA is generally synthesized by metal catalyzed Ring Opening Polymerization (ROP), and the problem now is how to modify degradable material catalysts and polyester materials, expanding the application range of cyclic ester materials such as application in biomedical fields like sutures and drug carriers, commodity packaging materials, gene delivery carriers, etc. At the same time, recycling of plastics is also challenging, and most of them are still being used in landfills or other dumping. For unreasonable recycling, innovation and development of alternative strategies are needed to economically convert plastic waste into valuable products, enabling efficient recycling to cope with the difficult challenges facing modern society.
In order to realize circular economy, the catalyst is further developed to realize multifunctional catalysis, so that the method is an effective method for obtaining the biodegradable material PLA with better performance, and is also a key for solving the chemical degradation problem of the scrapped degradable plastic PLA.
Disclosure of Invention
Aiming at the problems that the existing partial polyester catalyst has biotoxicity and poor polymerization controllability, and most of the catalyst cannot realize the depolymerization of the polylactide, the invention provides a difunctional tetranuclear metal lithium complex, a preparation method and application thereof.
The invention aims to provide a difunctional tetranuclear lithium metal complex catalyst which has few side reactions, high conversion rate, good selectivity and double catalytic functions, and a synthesis method and application thereof.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a bifunctional tetranuclear lithium metal complex having the structural formula:
the crystal of the difunctional tetranuclear lithium metal complex belongs to a monoclinic system, and the space group C2/C has the following unit cell parameters:α=90(13)°,β=104.358(5)°,γ=90°。
a preparation method of a difunctional tetranuclear metal lithium complex comprises the following synthetic routes:
the method comprises the following steps: dissolving silicon bridged amino quinaldine in diethyl ether, dropwise adding n-butyl lithium with the same molar weight as the silicon bridged amino quinaldine under the anhydrous and anaerobic condition at the temperature of 0 ℃ while stirring, then recovering to the room temperature condition, continuously stirring for 3-8 hours, standing after the reaction is finished, filtering to remove filtrate, washing and purifying the filtrate with n-hexane for multiple times, concentrating the filtrate, and crystallizing to obtain the difunctional tetranuclear lithium metal complex.
Further, the crystallization is specifically carried out by dissolving the obtained solid product in tetrahydrofuran, concentrating, and crystallizing by standing at a low temperature of-30 ℃ under nitrogen protection.
Further, the concentration of n-butyllithium was 2.5mol/L.
The application of the difunctional tetranuclear lithium metal complex is applied to lactide polymerization and polylactide degradation.
Further, the lactide polymerization product is obtained in a methylene chloride solvent under the condition of no cocatalyst or the condition of being co-catalyzed with a cocatalyst benzyl alcohol.
Further, lactide is polymerized under an inert atmosphere at room temperature of 20 to 30 ℃.
Further, the molar ratio of the lactide to the difunctional tetranuclear lithium metal complex is 100:1-400:1.
Further, under the condition of co-catalysis with methanol, the degradation products of the polylactide are obtained in a methylene chloride solvent.
Further, the specific method for obtaining the degradation product of the polylactide in the methylene chloride solvent under the condition of being co-catalyzed with the methanol is as follows: preparing an oil bath with the temperature stabilized at 20-30 ℃; accurately weighing the complex in inert atmosphere, adding the complex into an A bottle with a stirrer, and then adding dichloromethane until the complex is completely dissolved; under the same condition, preparing a B bottle, adding the B bottle according to the molar ratio of the lactide to the difunctional tetranuclear metal lithium complex of 100:1, and dissolving the B bottle in dichloromethane; adding the mixed monomer in the bottle B into the bottle A with constant rotating speed, and simultaneously monitoring in real time to ensure complete polymerization; then adding the polylactide and the methanol at a molar ratio of 10:1 at 600 rpm; sampling and measuring every 10min 1 HNMR once monitors depolymerization reaction in real time, and after waiting for 1h, the polylactide is completely degraded into methyl lactate.
Compared with the prior art, the invention has the following advantages:
the difunctional tetranuclear metal lithium complex as a catalyst has the characteristics of no toxicity, high efficiency, controllability and the like, the monomer conversion rate in the polymerization process is higher than 90%, and the polylactide with controllable molecular weight and narrow molecular weight distribution degree can be obtained. Meanwhile, the degradation and recovery of biodegradable plastic are realized, and the multifunctional catalytic degradation is carried out to obtain green solution, so that the economic green circulation is achieved.
Drawings
FIG. 1 is a single crystal X-ray structure diagram of a bifunctional tetranuclear lithium metal complex of the present invention.
Detailed Description
All reactions were carried out under the protection of high purity nitrogen or argon after drying over potassium column and operated using standard reaction techniques.
Example 1: synthesis of difunctional tetranuclear lithium metal complex
In a solution of silicon-bridged amino quinaldine (1.19 g,3.20 mmol) in diethyl ether (20 mL) under anhydrous and anaerobic conditions, dropwise add with stirring at 0deg.C n BuLi (3.00 mL,2.5M in n-hexane, 6.40 mmol). The solution immediately became turbid. The mixture was allowed to return to room temperature, stirred continuously for 3 hours, and purified by repeated washing with n-hexane to give 1.18g of a yellow solid as a final product in 81% yield.
Example 2: synthesis of difunctional tetranuclear lithium metal complex
In a solution of silicon-bridged amino quinaldine (1.19 g,3.20 mmol) in diethyl ether (30 mL) under anhydrous and anaerobic conditions, dropwise add with stirring at 0deg.C n BuLi (3.00 mL,2.5M in n-hexane, 6.40 mmol). The solution immediately became turbid. The mixture was allowed to return to room temperature, stirred continuously for 8 hours, and purified by repeated washing with n-hexane to give 1.18g of a yellow solid as a final product in 81% yield.
The test results of the products obtained in example 1 and example 2 are the same, and are described in detail below:
1 H NMR(600MHz,C 6 D 6 ):δ7.52(d,J=8.7Hz,5H,ArH),7.41(s,2H,ArH),7.38(t,J=7.7Hz,2H,ArH),7.07(t,J=8.1Hz,1H,ArH),6.94(d,J=8.1Hz,4H,ArH),6.80(s,2H,ArH),6.77(d,J=8.4Hz,2H,ArH),6.40(m,2H,ArH),3.33(m,8H,THF),2.51(s,3H,CH 3 ),1.89(s,4H,CH 3 ),1.28(m,8H,THF),0.88(s,5H,CH 3 ),0.45(s,6H,SiMe 2 ),0.30(s,6H,SiMe 2 ). 13 C NMR(151MHz,C 6 D 6 )δ158.75,155.41,155.32,146.56,139.10,137.71,136.08,121.66,121.21,117.48,115.58,110.87,109.42,67.36,45.63,25.23,24.68,23.88,4.29,2.07,1.02,-1.87.Anal.calcd for C 52 H 60 Li 4 N 8 O 2 Si 2 :C;68.41;H;6.62;N;12.27.Found:C;68.35;H,6.74;N,12.25。
example 3 structural determination of bifunctional tetranuclear lithium Metal Complex
Selecting a large partSmall, suitable crystals, crystal data were collected using a Bruker Apex II CCD diffractometer at room temperature, graphite monochromator Mo-kαAs a source of radiation. Unit cell parameters were determined using SMART software and absorption corrections were performed by the sadbs procedure. The crystal structure was solved directly using the SHELXS-2014 procedure and based on F using the full matrix least squares method 2 Finishing, and determining all H atom positions by theoretical hydrogenation. The crystal structure is shown in FIG. 1, and the crystallographic measurement data is shown in Table 1.
TABLE 1 Crystal data of difunctional tetranuclear lithium metal complexes
Partial bond lengthLi(1)-O(1),2.028(7);Li(1)-N(1),2.118(4);Li(1)-N(2),2.118(4);Li(1)-N(5),2.391(2);Li(1)-N(8),2.391(2);Li(2)-N(1),2.076(5);Li(2)-N(4)`,2.097(5);Li(2)-N(7),2.003(5);Li(2)-N(8),2.164(5);Li(3)-O(1),1.932(7);Li(3)-N(3),2.039(4);Li(3)-N(4),2.039(4);Li(4)-N(2),2.076(5);Li(4)-N(6),2.097(5);Li(4)-N(4),2.003(5);Li(4)-N(5),2.164(5);
Partial bond angle (°) N (1) -Li (1) -O (1): 81.7 (5); n (2) -Li (1) -N (1): 114.3 (2); n (1) -Li (1) -N (2): 113.98 (12); li (1) -N (1) -Li (2): 51.08 (11); li (2) -N (4) -Li (3): 89.4 (2); n (3) -Li (3) -N (4): 122.8 (3); li (3) -N (3) -Li (4): 44.06 (14).
Example 4: application of difunctional tetranuclear lithium metal complex catalyst
The compound of example 1 above (0.05 mmol) of example 1 was added to the reaction flask under nitrogen protection, followed by a further 5mL of dichloromethane solution, then a further 5mmol of lactide monomer solution, maintaining the monomers: catalyst: cocatalyst = 100:1:0, the temperature was controlled at 30 ℃ with stirring. After 4h of reaction, 0.1mL of the reaction mixture was analyzed by 600M nuclear magnetism. Meanwhile, 3 drops of glacial acetic acid are added to terminate the reaction, then 200mL of methanol is added to precipitate the product to obtain a white polymer, the supernatant is filtered, and then a proper amount of methanol is added to sufficiently clean the precipitate. Conversion was calculated to 99% and molecular weight distribution pdi=1.60. The PDI is detected by GPC.
Example 5: application of difunctional tetranuclear lithium metal complex catalyst
The compound described in example 1 (0.05 mmol) was added to the flask under nitrogen, followed by 5mL of methylene chloride solution, and then 50. Mu. Mol of benzyl alcohol as a cocatalyst, followed by stirring to react for 30min for pre-reaction. Subsequently, accurately add 5mmol of lactide monomer solution, keep monomer: catalyst: cocatalyst = 100:1:1, the temperature was controlled at 20 ℃ with stirring. After 4h of reaction, 0.1mL of the reaction mixture was analyzed by 600M nuclear magnetism. Meanwhile, 3 drops of glacial acetic acid are added to terminate the reaction, then 200mL of methanol is added to precipitate the product to obtain a white polymer, the supernatant is filtered, and then a proper amount of methanol is added to sufficiently clean the precipitate. Conversion was calculated to 98% and molecular weight distribution pdi=1.18. The PDI is detected by GPC.
Example 6: application of difunctional tetranuclear lithium metal complex catalyst
The compound described in example 1 (0.05 mmol) was added to the flask under nitrogen, followed by 5mL of methylene chloride solution, and then 50. Mu. Mol of benzyl alcohol as a cocatalyst, followed by stirring to react for 30min for pre-reaction. Subsequently, accurately add 5mmol of lactide monomer solution, keep monomer: catalyst: cocatalyst = 100:1:1, the temperature was controlled at 30 ℃ with stirring. After 4h of reaction, 0.1mL of the reaction mixture was analyzed by 600M nuclear magnetism. Meanwhile, 3 drops of glacial acetic acid are added to terminate the reaction, then 200mL of methanol is added to precipitate the product to obtain a white polymer, the supernatant is filtered, and then a proper amount of methanol is added to sufficiently clean the precipitate. Conversion was calculated to 98% and molecular weight distribution pdi=1.19. The PDI is detected by GPC.
Example 7: application of difunctional tetranuclear lithium metal complex catalyst
The compound described in example 1 (0.05 mmol) was added to the flask under nitrogen, followed by 5mL of methylene chloride solution, and then 50. Mu. Mol of benzyl alcohol as a cocatalyst, followed by stirring to react for 30min for pre-reaction. Subsequently, 10mmol of lactide monomer solution was accurately added, the monomers were kept: catalyst: cocatalyst = 200:1:1, the temperature was controlled at 30 ℃ with stirring. After 4h of reaction, 0.1mL of the reaction mixture was analyzed by 600M nuclear magnetism. Meanwhile, 3 drops of glacial acetic acid are added to terminate the reaction, then 200mL of methanol is added to precipitate the product to obtain a white polymer, the supernatant is filtered, and then a proper amount of methanol is added to sufficiently clean the precipitate. Conversion was calculated to 99%, molecular weight distribution pdi=1.21. The PDI is detected by GPC.
Example 8: application of difunctional tetranuclear lithium metal complex catalyst
The compound described in example 1 (0.05 mmol) was added to the flask under nitrogen, followed by 5mL of methylene chloride solution, and then 50. Mu. Mol of benzyl alcohol as a cocatalyst, followed by stirring to react for 30min for pre-reaction. Subsequently, 20mmol of lactide monomer solution was accurately added, the monomers were maintained: catalyst: cocatalyst = 400:1:1, the temperature was controlled at 30 ℃ with stirring. After 4h of reaction, 0.1mL of the reaction mixture was analyzed by 600M nuclear magnetism. Meanwhile, 3 drops of glacial acetic acid are added to terminate the reaction, then 200mL of methanol is added to precipitate the product to obtain a white polymer, the supernatant is filtered, and then a proper amount of methanol is added to sufficiently clean the precipitate. Conversion was calculated to 98% and molecular weight distribution pdi=1.30. The PDI is detected by GPC.
Example 9: application of difunctional tetranuclear lithium metal complex catalyst
An oil bath at 20℃was prepared in advance, and the compound described in example 1 (0.05 mmol) was added to a Schlenk flask equipped with a stirrer under nitrogen protection, and 5mL of methylene chloride was added to dissolve completely. Then according to [ LA ]]:[Cat]To the addition of lactide monomer in a ratio of =100:1, samples were taken every 1h for measurement 1 HNMR was used once, the polymerization was monitored in real time and after waiting for 4 hours the conversion exceeded 99%. Subsequently 2.0mL MeOH (n) PLA :n MeOH =10:1), the depolymerization reaction was monitored in real time,after waiting for 1h the conversion rate exceeded 99%, the polylactide was completely degraded into methyl lactate (Me-La).
Example 10: application of difunctional tetranuclear lithium metal complex catalyst
An oil bath at 30℃was prepared in advance, and the compound described in example 1 (0.05 mmol) was added to a Schlenk flask equipped with a stirrer under nitrogen protection, and 5mL of methylene chloride was added to dissolve completely. Then according to [ LA ]]:[Cat]To the addition of lactide monomer in a ratio of =100:1, samples were taken every 1h for measurement 1 HNMR was used once, the polymerization was monitored in real time and after waiting for 4 hours the conversion exceeded 99%. Subsequently 2.0mL MeOH (n) PLA :n MeOH =10:1), the depolymerization reaction was monitored in real time, the conversion rate exceeded 99% after waiting for 1h, and the polylactide was completely degraded to methyl lactate (Me-La).
What is not described in detail in the present specification belongs to the prior art known to those skilled in the art. While the foregoing describes illustrative embodiments of the present invention to facilitate an understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, but is to be construed as protected by the accompanying claims insofar as various changes are within the spirit and scope of the present invention as defined and defined by the appended claims.
Claims (10)
1. A difunctional tetranuclear lithium metal complex characterized in that: the structural formula of the difunctional tetranuclear lithium metal complex is as follows:
the crystal of the difunctional tetranuclear lithium metal complex belongs to a monoclinic system, and the space group C2/C has the following unit cell parameters:α=90(13)°,β=104.358(5)°,γ=90°。
2. the method for preparing the difunctional tetranuclear lithium metal complex according to claim 1, wherein the method is characterized in that: the method comprises the following steps: dissolving silicon bridged amino quinaldine in diethyl ether, dropwise adding n-butyl lithium with the same molar weight as the silicon bridged amino quinaldine under the anhydrous and anaerobic condition at the temperature of 0 ℃ while stirring, then recovering to the room temperature condition, continuously stirring for 3-8 hours, standing after the reaction is finished, filtering to remove filtrate, washing and purifying the filtrate with n-hexane for multiple times, concentrating the filtrate, and crystallizing to obtain the difunctional tetranuclear lithium metal complex.
3. The method for preparing the difunctional tetranuclear lithium metal complex according to claim 2, wherein the method is characterized in that: the specific method of crystallization is to dissolve the obtained solid product in tetrahydrofuran, concentrate, and precipitate crystals under nitrogen protection at low temperature-30 ℃.
4. The method for preparing the difunctional tetranuclear lithium metal complex according to claim 2, wherein the method is characterized in that: the concentration of the n-butyllithium is 2.5mol/L.
5. The use of a bifunctional tetranuclear lithium metal complex prepared by the preparation method of claim 2, wherein: is applied to lactide polymerization and polylactide degradation.
6. The use according to claim 5, characterized in that: the lactide polymerization product is obtained in methylene dichloride solvent under the condition of no cocatalyst or the condition of co-catalysis with the cocatalyst benzyl alcohol.
7. The use according to claim 6, characterized in that: lactide is polymerized under the inert atmosphere of 20-30 ℃ at room temperature.
8. The use according to claim 7, characterized in that: the molar ratio of the lactide to the difunctional tetranuclear metal lithium complex is 100:1-400:1.
9. The use according to claim 5, characterized in that: under the condition of being co-catalyzed with methanol, the degradation products of the polylactide are obtained in methylene dichloride solvent.
10. The use according to claim 9, characterized in that: the specific method for obtaining the degradation product of the polylactide in the methylene dichloride solvent under the condition of being co-catalyzed with the methanol is as follows: preparing an oil bath with the temperature stabilized at 20-30 ℃; accurately weighing the complex in inert atmosphere, adding the complex into an A bottle with a stirrer, and then adding dichloromethane until the complex is completely dissolved; under the same condition, preparing a B bottle, adding the B bottle according to the molar ratio of the lactide to the difunctional tetranuclear metal lithium complex of 100:1, and dissolving the B bottle in dichloromethane; adding the mixed monomer in the bottle B into the bottle A with constant rotating speed, and simultaneously monitoring in real time to ensure complete polymerization; then adding the polylactide and the methanol at a molar ratio of 10:1 at 600 rpm; sampling and measuring every 10min 1 HNMR once monitors depolymerization reaction in real time, and after waiting for 1h, the polylactide is completely degraded into methyl lactate.
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