177 results about "Butyllithium" patented technology

The invention discloses water-based formaldehyde-free woodworking glue and a preparation method thereof, and relates to the technical field of woodworking glue. When the water-based formaldehyde-free woodworking glue is prepared, firstly, n-butyllithium is used as an initiator to initiate cyclosiloxane and an acrylate monomer to be polymerized, then dimethyl chlorosilane is used for blocking to obtain pre-modified polyacrylate, and the pre-modified polyacrylate is used for preparing the water-based formaldehyde-free woodworking glue. Reacting the pre-modified polyacrylate with vinyl diphenylphosphine, and then reacting with 3-(4-bromophenyl)-1-propylene to obtain modified polyacrylate; secondly, reacting the 4-(trimethoxysilyl) butyraldehyde modified silicon dioxide with chitosan, and then reacting with mercaptoacetic acid to obtain modified silicon dioxide; finally, mixing the modified polyacrylate, the modified silicon dioxide, an emulsifier, a defoaming agent, pure water and a photoinitiator to obtain the water-based formaldehyde-free woodworking glue. The water-based formaldehyde-free woodworking glue prepared by the invention has flame retardance and antibacterial property.

The invention discloses tris (dimethylamino) cyclopentadienyl hafnium and a preparation process thereof.The preparation process of the tris (dimethylamino) cyclopentadienyl hafnium comprises the following steps that S1, an n-hexane solution of n-butyllithium and dimethylamine are subjected to a reaction, and a lithium dimethylamino emulsion is obtained; s2, adding hafnium tetrachloride into the lithium dimethylamino emulsion for reaction, and separating to obtain a liquid-phase product; s3, the liquid-phase product is heated, a tetra (dimethylamino) hafnium concentrated solution is obtained, and the volume of the tetra (dimethylamino) hafnium concentrated solution is 20%-30% of the volume of the liquid-phase product; and S4, obtaining cyclopentadiene, adding the cyclopentadiene into the tetra (dimethylamino) hafnium concentrated solution to react, and filtering to obtain tris (dimethylamino) cyclopentadienyl hafnium. According to the preparation process of the tris (dimethylamino) cyclopentadienyl hafnium, complex solvent components are not needed, the preparation efficiency is improved, and the use amount of the solvent and the preparation cost are reduced.

The invention relates to a novel preparation method of tetra (dimethylamino) tin. The method comprises the following steps: in a nitrogen atmosphere, pumping an n-hexane solution of n-butyllithium and an n-hexane solution of dimethylamine into a pipeline through a propeller, mixing through a T-shaped joint, and reacting through a flow reactor 1 and a flow reactor 2 to obtain a lithium dimethylamide mixed solution; the method comprises the following steps: pumping a lithium dimethylamino mixed solution and a n-hexane solution of tin tetrachloride into a pipeline through a propeller, mixing through a T-shaped joint, and reacting through a flow reactor 3 and a flow reactor 4 to obtain a crude tetra (dimethylamino) tin product; and centrifuging and filtering the tetra (dimethylamino) tin crude product, adsorbing impurities by adopting a resin column, and carrying out reduced pressure distillation to remove the solvent, thereby obtaining the tetra (dimethylamino) tin. The adsorption resin column adopts modified macroporous adsorption resin, and is obtained by reacting, filtering and drying D190 macroporous styrene sulfydryl resin, dichloroethane, tetramethylguanidine, 5-allylpyrimidine-4, 6-diol and an ethylene boric anhydride pyridine complex.

The invention provides primary amino modified solution polymerized styrene-butadiene rubber and a preparation method thereof. The preparation method comprises the following steps: in a polymerization system, initiating polymerization of a butadiene monomer and a styrene monomer by taking n-butyllithium as an initiator and tetrahydrofuran as a polymerization activator to obtain a styrene butadiene rubber active chain; adding a diisocyanate compound into the polymerization system to terminate polymerization, and introducing an isocyanate group to the end part of a styrene butadiene rubber active chain to obtain a styrene butadiene rubber solution; and adding a terminator into the styrene-butadiene rubber solution, stirring, separating out precipitate, and drying to obtain the primary amino modified solution polymerized styrene-butadiene rubber. The primary amino modified solution polymerized styrene-butadiene rubber is prepared by the preparation method, has high polarity and strong binding force with silicon dioxide filler, promotes generation of a more stable filler-polymer network with a more perfect structure, and remarkably improves the dynamic performance of a rubber material.

The invention discloses a butyl lithium solid-liquid separation continuous reaction device and a butyl lithium preparation method. According to the reaction device, through double-layer convection stirring and a baffle plate with a pyramid tip, full contact of metal lithium and halogenated alkane is realized on the premise of not dispersing lithium, the problem of excessive consumption of the metal lithium and the halogenated alkane is solved, and the problem of blockage of a filtering device in a traditional process is solved through a top discharging and bottom filtering mode; according to the method, excessive lithium metal and halogenated alkane react in the liquid-phase solvent, so that the yield of halogenated alkane is increased, excessive lithium can continue to participate in the synthesis reaction of the next kettle of butyl lithium, the content of lithium metal in the product discharged from the reactor is greatly reduced in the process on the premise of ensuring the yield of the butyl lithium product, the utilization rate of lithium is increased, and the production cost is reduced. And industrial production is facilitated.

The invention belongs to the technical field of high polymer materials, and particularly relates to a phosphoric acid doped quaternized poly (alkane biphenyl-imidazole formaldehyde-biphenyl) polymer electrolyte membrane and a preparation method thereof. The preparation method comprises the following steps: in a nitrogen environment, adding 2-brominated biphenyl into tetrahydrofuran, uniformly stirring, adding n-butyllithium at-78 DEG C, stirring, adding halogenated alkane, and continuously stirring to obtain 2-alkane biphenyl; the preparation method comprises the following steps: carrying out Friedel-Crafts reaction on 2-alkane biphenyl, biphenyl and 4-imidazole formaldehyde, and carrying out strong acid catalytic polymerization to obtain a poly (alkane biphenyl-imidazole formaldehyde-biphenyl) polymer; carrying out quaternization treatment to obtain a polymer subjected to quaternization treatment; and finally carrying out phosphoric acid doping to obtain the polymer electrolyte membrane. A long alkyl chain is grafted to a main chain to construct microphase separation, more channels are provided for proton transmission, quaternization treatment is adopted, so that the polymer electrolyte membrane has higher acid absorption capacity, and the ether-free main chain can improve the mechanical property of the membrane.

The invention discloses an anti-aging and anti-corrosion coating and a preparation method thereof, and relates to the technical field of coatings. When the anti-aging and anti-corrosion coating is prepared, firstly, tetramethyl tetravinyl cyclotetrasiloxane, n-butyllithium and dimethyl-3-chloropropyl chlorosilane react to obtain modified polysiloxane, then 4-vinylpyridine, methyl methacrylate and n-butyl acrylate are copolymerized and then react with the modified polysiloxane, and then bis (4-chlorphenyl) phosphine is grafted to obtain the anti-aging and anti-corrosion coating. Finally, reacting with p-aminodiphenylamine to obtain modified acrylic resin; secondly, enabling the titanium dioxide nanosheet pretreated by 3-aminopropyltrimethoxysilane to react with ester phthalocyanine, and then hydrolyzing to obtain a modified titanium dioxide nanosheet; finally, mixing the modified acrylic resin, the modified titanium dioxide nanosheet, a solvent, a dispersing agent and a defoaming agent to obtain the anti-aging and anti-corrosion coating. The anti-aging and anti-corrosion coating prepared by the invention has excellent anti-aging, anti-corrosion, flame-retardant and antibacterial properties.

The invention belongs to the technical field of electrochromic materials, and provides a red-transparent display electrochromic polymer and a preparation method thereof. The method disclosed by the invention comprises the following steps: carrying out ring formation reaction on N-(2, 5-dibromophenyl)-2-ethylhexyl thioamide, potassium ferricyanide and sodium hydroxide to obtain 4, 7-dibromo-2-(heptane-3-yl) benzothiazole; the preparation method comprises the following steps: carrying out substitution reaction on EDOT, n-butyllithium and tributyltin chloride to obtain EDOT-Sn; the preparation method comprises the following steps: carrying out Stille coupling reaction on 2, 4, 7-dibromo-2-(heptane-3-yl) benzothiazole and EDOT-Sn, and then carrying out electrochemical polymerization reaction to obtain the electrochromic polymer. A pure donor (D) type organic molecule is obtained by the method, a corresponding electrochromic film is prepared by electrochemical polymerization, reversible switching between red and transparency is realized, and the electrochromic film has good cycle stability and high color change response speed.

The invention belongs to the technical field of organic synthesis and medicinal chemistry, and discloses a total synthesis method of rhododendron heteroterpenin Rhododaurines A-C. The total synthesis method comprises the following steps: carrying out allyl stereoselective addition on a compound 3 and a compound 5 in a toluene solvent under the conditions of catalysis of n-butyllithium and low temperature of-78 DEG C, and constructing a chiral center to obtain a compound 6; removing a methoxy methyl (MOM) protecting group from the compound 6 under an acidic condition, cyclizing, and reacting to generate rhododaurine C (7); the rhododaurine C (7) is subjected to intramolecular [4 + 2] cycloaddition and oxidation reaction in the illumination and oxygen atmosphere of 300-385 nm, and rhododaurine B (8) and an epoxy epimer epinedodaurine B (9) are obtained; and carrying out protonation and rearrangement on the epidodaurine B (9) by virtue of acid catalysis cyclic ether, so as to generate the rhododaurine A (10). The method can overcome the defects that the content of rhododendron miscellaneous terpenoids Rhododaurines A-C in nature is extremely low, and large-scale extraction is difficult.

The invention provides a method for preparing a CGC ligand, which comprises the following steps: mixing tetra-substituted cyclopentadiene and n-butyllithium under a mechanical vibration condition, carrying out lithiation reaction under an ultrasonic condition, and then carrying out silicification reaction with a disubstituted dichlorosilane solution, the preparation method comprises the following steps: preparing a silicification product into a tetrahydrofuran solution of the silicification product by using tetrahydrofuran, mixing primary amine and n-butyllithium under a mechanical vibration condition, carrying out lithiation reaction under an ultrasonic condition, carrying out amination reaction on an obtained lithiation reaction solution and the prepared tetrahydrofuran solution of the silicification product, and carrying out post-treatment on the obtained amination reaction solution to obtain the CGC ligand. According to the method for preparing the CGC ligand, the CGC ligand is continuously prepared by coupling the ultrasonic microreactor with local mechanical vibration, the danger coefficient is low, the reaction efficiency is high, the cost is saved, the period is short, and meanwhile, the problem that an organic lithium intermediate generated by lithiation reaction is deposited in the microreactor is solved.

The invention discloses a synthesis method of a novel benzosuberone compound, and belongs to the field of organic synthesis. The preparation method comprises the following steps: uniformly stirring methyltriphenylphosphonium bromide in a solvent at room temperature, dropwise adding an n-hexane solution of n-butyllithium in an ice-water bath, stirring a reaction system at room temperature for 30-40 minutes after dropwise adding is completed, then adding an initial raw material phenanthrenequinone 1 in the ice-water bath, transferring the reaction system to 40 DEG C for reaction, and after the reaction is monitored to be complete by a TLC (Thin Layer Chromatography) dot plate, filtering, washing and drying to obtain the phenanthrenequinone 1. And pouring the reaction liquid into a silica gel chromatographic column, and simply filtering by using dichloromethane as an eluent to remove salt and phosphine oxide. And performing rotary evaporation to remove the organic solvent to obtain a crude product, and separating and purifying to obtain a target product 2. The method is short in reaction time and low in reaction cost, provides a practical method for obtaining the seven-membered rigid ring skeleton, and has potential value for synthesis of natural products and bioactive molecules.

The invention provides an in-chain functionalized solution polymerized styrene-butadiene rubber and an in-chain modification method thereof. The method comprises the following steps: in a polymerization system, initiating polymerization of a butadiene monomer and a styrene monomer by taking n-butyllithium as an initiator and tetrahydrofuran as a polymerization activator to obtain a styrene butadiene rubber active chain; adding a terminator into the polymerization system to terminate the polymerization reaction to obtain a styrene butadiene rubber solution; the method comprises the following steps: adding a thiol compound and a free radical initiator into a styrene-butadiene rubber solution, heating and stirring the styrene-butadiene rubber solution, after a modification reaction is finished, adding alcohol to separate out and precipitate the styrene-butadiene rubber, and drying to obtain the chain-functionalized solution polymerized styrene-butadiene rubber. The in-chain functionalized solution polymerized styrene-butadiene rubber is prepared by the preparation method, and the interface bonding force between the white carbon black and the styrene-butadiene rubber can be enhanced, so that the hysteresis loss of a final tire rubber product is reduced, and the tire rubber product is endowed with high wear resistance, fatigue resistance and excellent wet skid-rolling resistance balance.

The invention belongs to the field of polymer electrolyte membranes, and particularly relates to a block type anion exchange membrane with interstitial alkyl chains and a preparation method of the block type anion exchange membrane. The preparation method comprises the following steps: adding a tetrahydrofuran solution of n-butyllithium into dehydrated toluene for reaction, and then adding alpha, omega-dihaloalkane for reaction to obtain alpha, omega-diphenylalkane; the preparation method comprises the following steps: prepolymerizing biphenyl and 4-imidazole formaldehyde to obtain a prepolymer 1, and prepolymerizing alpha, omega-diphenylalkane and 4-imidazole formaldehyde to obtain a prepolymer 2; mixing the two prepolymerization solutions to obtain a fibrous block polymer with an interstitial alkane chain; and finally, carrying out quaternization and ion replacement to obtain the anion exchange membrane. Microphase separation is constructed in the polymer membrane through a block structure, and the conductivity is improved; an interstitial alkyl chain is introduced into an AEMs main chain to reduce the rigidity of polybiphenyl and improve the flexibility of the membrane; the alkali resistance of the polymer electrolyte membrane is enhanced through the main chain design without ether bonds.

The invention provides a preparation method of a chlorantraniliprole key intermediate 2-amino-5-cyano-N, 3-dimethyl benzamide, which comprises the following steps: taking cheap and easily available o-methylaniline as a raw material, acylating an aniline substrate through Boc anhydride, carrying out ortho-lithiation on n-butyllithium, introducing carbon dioxide gas, and carrying out acid hydrolysis to obtain 2-amino-3-methyl benzoic acid, thereby obtaining the chlorantraniliprole key intermediate 2-amino-5-cyano-N, 3-dimethyl benzamide. The preparation method comprises the following steps: firstly, preparing an isatoic anhydride intermediate, then carrying out triphosgene ring closing to obtain an isatoic anhydride intermediate, carrying out bromine para-position halogenation, carrying out cuprous cyanide high-temperature Rosenmn-von Braun reaction, and finally carrying out methylamine ring opening to obtain the target product 2-amino-5-cyano-N, 3-dimethylbenzamide, and although the route is long, the yield is high, the continuity is good, few industrial three wastes are generated, and the cost is lower, so that the preparation method has great industrial production value.

The invention relates to the field of biomedical polymer materials, and discloses a preparation method of high-viscosity photo-crosslinking sodium hyaluronate hydrogel, which comprises the following steps: dissolving sodium hyaluronate in deionized water / N, N-dimethylformamide to obtain a sodium hyaluronate solution; mixing the sodium hyaluronate solution and the conjugated diene glycidyl ester / N, N-dimethylformamide solution to obtain a pre-formed sodium hyaluronate glue solution; composite antibacterial microspheres and a photoinitiator are added into the preformed sodium hyaluronate glue solution, a photo-crosslinking reaction is performed, conjugated diene glycidyl ester is prepared from raw materials including n-butyllithium, ethyl acetate, 2, 3-dibromo-1-propylene, vinyl magnesium chloride, sodium hydroxide and glycidol, and the conjugated diene glycidyl ester is prepared from raw materials including sodium hyaluronate, sodium hyaluronate and sodium hyaluronate. According to the preparation method disclosed by the invention, the modification reaction and photo-crosslinking time is shortened through the grafting of conjugated diene glycidyl ester, the viscosity of the hydrogel is greatly improved, and the antibacterial property of the hydrogel is improved through the addition of the composite antibacterial microspheres.

The invention discloses chain end modified liquid rubber, mixed rubber, a preparation process, a tire and a vehicle, and belongs to the technical field of liquid rubber and manufacturing thereof. According to the liquid rubber, butadiene monomers and a chain transfer agent are added in batches in the preparation process, negative ion active centers are frequently transferred to the chain transfer agent from the tail end of a polybutadiene-based lithium active chain to form new initiation growth centers, then newly introduced butadiene monomers are initiated to grow, the dosage of an n-butyllithium initiator is remarkably reduced, and the stability of the liquid rubber is improved. The production cost is greatly reduced, the generation of sewage is greatly avoided, the monomer concentration of the final rubber product can reach about 80 percent by weight, the productivity is improved, and large-scale production is facilitated; the rubber also enables the filler to have good dispersibility, and has good compatibility with base rubber such as styrene butadiene rubber, natural rubber and the like.

The device comprises a magnetic flocculation reactor, a centrifugal separator is arranged on one side of the magnetic flocculation reactor, a reaction kettle is arranged on one side of the centrifugal separator, and a spiral cleaning machine is arranged on one side of the reaction kettle, and is characterized in that a first driving motor is arranged at the bottom of the centrifugal separator; a driving fulcrum shaft is installed at the output end of the upper surface of the first driving motor, a drum body is arranged in the middle of one side of the outer surface of the driving fulcrum shaft, a plurality of inner cone layers are installed in the drum body, and outer cone layers are arranged on the top of the outer surface of the driving fulcrum shaft side by side. Through cooperation of the first driving motor, the driving fulcrum shaft, the inner cone layer, the outer cone layer and the hydraulic telescopic rod, the taper of the rotary drum body can be dynamically adjusted according to the viscosity of waste liquid, and the solid-liquid separation efficiency is remarkably improved in combination with the spiral flow guide edges on the inner wall.

The utility model provides an n-butyllithium taking bottle which comprises a bottle body and a bottle cap and is characterized in that the bottle body is composed of an inner layer structure and an outer layer structure, an air inlet pipe and a liquid outlet pipe are arranged on the bottle cap, an air inlet valve is arranged on the air inlet pipe, a liquid outlet valve and a buckle are arranged on the liquid outlet pipe, and the liquid outlet pipe and a feeding pipe are connected through the buckle. And an air bag and a feeding needle are arranged on the feeding pipe. The n-butyllithium taking device is connected with an air inlet and liquid outlet device, so that the n-butyllithium taking device is safer when n-butyllithium is taken. When the n-butyllithium bottle topples over or falls off accidentally, the two-layer structure can protect the bottle body from being broken, reagents in the bottle are not prone to being leaked, and accidents are reduced.

The invention discloses a novel method for synthesizing a ferrocenyl phosphine ligand compound, which comprises the following steps of: reacting a ferrocene compound serving as a starting material with a Grignard reagent and phosphorus trichloride under the action of tert-butyl lithium to generate a ferrocene phosphine ligand, and synthesizing a ferrocene diphosphine ligand in one step. The method is stable and high in practicability, and a novel method for synthesizing the ferrocene ligand compound is provided.

The invention provides a method for preparing dienogest through a one-pot method, and belongs to the technical field of medicine synthesis. The method comprises the following steps: forming ethyl cyano anions from n-butyllithium and acetonitrile under an ultra-low temperature condition, carrying out addition reaction on a compound in a formula (1), quenching with acid after the reaction is finished, and then directly dropwise adding concentrated hydrochloric acid to carry out deprotection-transposition reaction, so as to prepare a compound in a formula (2); and after the reaction is finished, adding a sodium bicarbonate aqueous solution to carry out elutriation, and carrying out secondary refining on an obtained crude product to obtain a refined dienogest product. The dienogest is prepared through the addition and deprotection-transposition reaction one-pot method, the solvent dosage can be effectively reduced, meanwhile, solid waste is reduced, the process cost is reduced, and green chemical industrial production of the dienogest is achieved.

The invention relates to a method for preparing (cyclopentadienyl) tris (dimethylamino) hafnium by using nuclear magnetic control, which comprises the following steps: S1, carrying out heating reflux reaction on hafnium tetrachloride, cyclopentadiene and dimethylamine in the presence of n-butyllithium and n-hexane, and after reacting for a certain time, taking supernate to detect a nuclear magnetic hydrogen spectrum; s2, calculating the ratio a of the integral area of the characteristic peak A to the integral area of the characteristic peak B according to the nuclear magnetic hydrogen spectrum, judging whether a is in a target range or not, if a is in the target range, terminating the reaction, separating a liquid phase, distilling and collecting a crude product; and if a value is greater than the maximum value of the target range, adding cyclopentadiene into the reaction system to continue the reaction, and if a value is less than the minimum value of the target range, continuing the reaction until the ratio of the integral area of the characteristic peak A to the integral area of the characteristic peak B in the nuclear magnetic hydrogen spectrum of the reaction supernatant is within the target range, terminating the reaction, separating the liquid phase, distilling and collecting a crude product. The method can effectively improve the safety of the production process, the raw material conversion rate and the product purity.

This invention provides a compound for recognizing chiral amino alcohols, a fluorescent probe, its preparation method, and its application. Naphthol and sodium hydride are weighed and dissolved separately in ultra-dry tetrahydrofuran, mixed, and then reacted with bromomethyl methyl ether. The mixture is extracted with ethyl acetate, and the organic phases are combined to obtain product (R)-1. This product is dissolved in ultra-dry tetrahydrofuran, and n-butyllithium is added. The reaction system changes from colorless to brown, and the reaction is allowed to return to room temperature. Ultra-dry N,N-dimethylformamide solution is then added, and the reaction is quenched by adding saturated ammonium chloride solution under ice-water bath conditions. The product is then extracted with ethyl acetate to obtain product (R)-2. Product (R)-2 is dissolved in a mixed solvent of tetrahydrofuran and anhydrous methanol, and sodium triacetoxyborohydride is added. The product is then extracted with ethyl acetate to obtain reduced product (R)-3. Product (R)-3 is dissolved in a mixed solvent of dichloromethane and anhydrous ethanol, and concentrated hydrochloric acid is added. After the reaction is complete, the reaction is quenched with sodium bicarbonate, and then extracted with dichloromethane to finally obtain compound (R)-4, which recognizes chiral amino alcohols.

The invention belongs to the technical field of chemical synthesis of semiconductor materials, and particularly relates to a synthesis method of tetra (dimethylamino) titanium, which comprises the following steps: (1) reacting titanium tetrachloride with dimethylamine to generate an intermediate TiClx [N (CH3) 2] 4-x, where x is an integer from 0 to 4; (2) reacting dimethylamine with an organic metal lithium reagent to synthesize lithium dimethylamino (LiN (CH3) 2); and (3) reacting the intermediate obtained in the step (1) with lithium dimethylamino obtained in the step (2) to obtain tetra (dimethylamino) titanium. By adopting a step-by-step reaction strategy, the dependence on expensive n-butyllithium is fundamentally reduced, the raw material cost is remarkably reduced, meanwhile, the reaction process is optimized by generating an intermediate, the product yield is greatly improved, the generation of byproducts is effectively reduced, and the product purity is improved.

This invention relates to a simple method for modifying β-ketoimine ligand precursors, wherein L... Ph The reaction involves a lithium compound with H2 solution; then a haloalkane is added for C-C coupling; followed by the addition of an acid solution to complete the modification of the β-ketoimine ligand precursor, yielding a terminally alkylated ketoimine. This invention relates to a simple method for modifying β-ketoimine ligand precursors, specifically involving the removal of the proton at the α-position of the β-ketoimine ligand precursor from commercially available n-butyllithium to form a deprotonated β-ketoimine lithium compound, followed by C-C coupling to achieve alkylation at the α-position of the ketocarbonyl group, thus providing a convenient modification of the β-ketoimine ligand precursor.

The application discloses a preparation method of triethyl indium, and relates to the technical field of metal organic source synthesis, wherein a commonly used indium source is mainly trimethyl indium; the trimethyl indium is in a solid state at normal temperature, and is easy to cause the solid indium source to be easy to be hardened and to have excessive residues; when the solid indium source is used in a machine, the concentration output stability is worse than that of a liquid source; the liquid indium source will become an important indium source in the future; the operation method of the triethyl indium in preparation is more complicated; and the purity of the triethyl indium prepared by purification cannot reach a better ideal state. In the application, n-butyllithium and ethyl iodide are reacted under the protection of inert gas, then the reaction product is reacted with indium chloride to generate triethyl indium; the whole operation is simple, raw materials are easy to obtain, and the product has high purity; under the protection of inert gas, the interference of other solution reagents in the preparation process is reduced; therefore, high-quality triethyl indium raw materials can be purified and processed.

The application discloses a method for recovering lactic acid methyl ester by catalytic depolymerization of polylactic acid in one pot. The method comprises the following steps: mixing polylactic acid, amine nitrogen ligand and methanol, dissolving by adding a solvent, and then adding a n-butyllithium solution to carry out a depolymerization reaction; and after the reaction is completed, the solvent is removed by vacuum distillation, and the crude product is dried in vacuum to obtain lactic acid methyl ester product. The application does not need to synthesize a complex organic metal catalyst, the depolymerization condition is mild, and the generation of by-products such as low-molecular-weight oligomers is effectively reduced. Therefore, the application has the advantages of simplifying the catalyst preparation process, improving the depolymerization efficiency, reducing the cost and the like, and is suitable for industrialized recovery and cyclic utilization of polylactic acid.

The present invention belongs to the technical field of polymer compounds, and specifically relates to a metallocene catalyst and its preparation method and application. A ketone is mixed with dimethylformamide, and then a tetrahydrofuran solution of chloroethane is added to react with imidazole to obtain solid A; solid A is dissolved in tetrahydrofuran, and then a n-butyl lithium n-hexane solution is added and stirred for reaction, and then hexamethylphosphoric triamide is added and stirred for reaction, and the temperature is lowered, and carbon tetrabromide is added and stirred, and the temperature is raised to room temperature to obtain a reaction solution; the reaction solution is extracted, and the solvent is removed in vacuo to obtain solid B; solid B is dissolved in tetrahydrofuran, and then potassium carbonate, potassium iodide and amine are added and stirred at room temperature to react to obtain component A; ZrCl4 is stirred with tetrahydrofuran to obtain component B; component A is dissolved to obtain solution A, component B is dissolved to obtain solution B, and solution A and solution B react to obtain a metallocene catalyst. The metallocene catalyst of the present invention has the characteristics of simple synthesis and high activity, and the obtained product polymer has a low Tg.

A method for preparing high-purity lithium sulfide by using industrial-grade butyllithium includes the following steps: step A: under an inert gas condition, thoroughly mixing 1.5-2.5 g of lithium chloride, 0.5 L of an industrial-grade n-butyllithium solution (2.5 mol / L) and 1.5-2.5 L of n-hexane to obtain a mixed solution, and charging the mixed solution into a sealed container; step B: under the sealed condition, firstly introducing H2S gas into a gas-washing bottle through a submerged pipe at a rate of 10.5 L / h, then introducing into the mixed solution through the submerged pipe, controlling the reaction temperature at 25-40° C., and continuously stirring for reaction for 4-6 h to obtain a reaction slurry; and step C: under an inert gas condition, filtering the reaction slurry with a G3 sand core funnel to obtain a crude lithium sulfide solid wet material.

The invention provides a novel method for preparing an intermediate compound of aromatic sesquiterpenes Commiphoranes C-D. The method comprises the following steps: substituting the ortho-position of a compound 1 with iodine through n-butyllithium and diiodoethane to obtain a compound 2; removing methoxyl by using boron tribromide to obtain a compound 3; performing nucleophilic substitution on 3-allyl bromide and potassium carbonate to synthesize a compound 4; carrying out Grignard reaction to obtain a compound 5; oxidizing into a compound 6 through a Dess-Martin oxidizing agent; finally, (CH3Si) 3SiH and triethyl boron are subjected to intramolecular free radical series cyclization, so that synthesis of an aromatic sesquiterpene Commiphoranes C-D intermediate compound is successfully completed, sufficient preparation is made for follow-up total synthesis of the natural product, key intramolecular free radical series cyclization has the capacity of efficiently constructing a polycyclic system, and the synthesis process is simple and convenient. According to the preparation method, the defects of expensive reagents, long 14-step linear synthesis route, low yield and the like in the existing synthesis route are overcome; the popularization potential is high.

The invention discloses a method for synthesizing beta-ketone ester, which comprises the following steps: mixing an organic metal reagent solution and an ester A solution in a first microchannel reactor, reacting I to obtain an enol intermediate, mixing the enol intermediate and an ester B solution in a second microchannel reactor, reacting II, and carrying out acid quenching to obtain the beta-ketone ester, the first micro-channel reactor and the second micro-channel reactor are communicated in sequence; the organic metal reagent is selected from at least two of methyl lithium, n-butyllithium, sec-butyllithium, lithium diisopropylamide, lithium bis (trimethylsilyl) amide, sodium bis (trimethylsilyl) amide, potassium bis (trimethylsilyl) amide and potassium tert-butoxide; a solvent in the organic metal reagent solution is selected from at least one of tetrahydrofuran, normal hexane, cyclohexane and normal heptane.