68results about How to "Safe preparation" patented technology

The invention relates to a catalyst for synthesizing ortho-cresol as well as a preparation method and application of the catalyst. The molar ratio of Zn element to Al element in the metal spinel catalyst ZnAl2O4 is 1: (0.25-16), and the preparation method comprises the following steps: uniformly mixing aluminum nitrate nonahydrate and zinc nitrate hexahydrate in deionized water, stirring, adding a precipitator, and adjusting the pH value of the solution to form a precipitate dispersion liquid; and aging the precipitate dispersion liquid, carrying out suction filtration on the suspension liquid, washing, drying, and calcining to obtain the catalyst. Compared with the prior art, the catalyst disclosed by the invention is high in activity, simple to prepare, non-toxic, good in stability, long in service life, suitable for synthesizing o-cresol and 2, 6-xylenol through reaction of phenol and methanol, good in ortho-selectivity and few in by-products.

The invention discloses a powder material for cosmetics and a preparation method thereof, and relates to the technical field of cosmetic raw materials, and the preparation method comprises the following steps: S1, compounding mica powder and pearl powder; s2, co-modifying a surface silicon source and a zinc source; s3, a silane coupling agent KH560, amino silicon oil and Meso-tetramethyl-meso-tetra (p-aminophenyl) calix [4] pyrrole are adopted for secondary modification. The powder material for cosmetics disclosed by the invention is good in hydrophobicity, excellent in skin feeling and sufficient in dispersity and stability.

The invention discloses high-purity oxamide with concentrated particle size and spherical morphology, a preparation method of the high-purity oxamide and application of the high-purity oxamide in preparation of a slow-release fertilizer, and belongs to the technical field of oxamide synthesis and application. The method comprises the following steps: mixing an ammonia-alcohol solution and an alcohol ester solution, conveying the mixed solution into a series tubular reactor for reaction, and then conveying the mixed solution into a parallel tubular reactor for reaction after pressure stabilization and flow equalization to obtain a reaction solution containing oxamide; performing flash evaporation on the reaction liquid to obtain flash evaporation liquid and flash evaporation gas, and performing solid-liquid separation on the flash evaporation liquid to obtain solid oxamide and filtrate; and drying the solid oxamide to obtain the oxamide. The method realizes high conversion rate and high purity, and the product has ultrafine particle size distribution. The purity of the prepared oxamide is greater than or equal to 99%, the D50 particle size is concentrated to 50 + / -15 microns, the spherical morphology is uniform, the release is stable, and the oxamide has a very good effect in preparation of long-acting slow-release fertilizers and combustion inhibitors and research on the nitrogen utilization rate.

The invention discloses a three-dimensional porous graphene / ferric oxide electromagnetic shielding composite film and a preparation method thereof, and belongs to the technical field of functional composite materials. In order to reduce or eliminate electromagnetic radiation, the three-dimensional porous rGO / Fe3O4 composite material is prepared by taking nano Fe3O4 and GO as raw materials and adopting a graphene oxide reduction self-assembly nanoparticle capturing method. The porous 3D rGO / Fe3O4 composite electromagnetic shielding material is obtained by mixing a dispersing agent and Fe3O4, adding the mixture into a graphene oxide dispersion liquid and capturing nano Fe3O4 through a graphene oxide reduction self-assembly process. Drying the 3D rGO / Fe3O4, and then mixing the 3D rGO / Fe3O4 with waterborne polyurethane to prepare an rGO / Fe3O4 / waterborne polyurethane composite coating; and coating the slurry on a base material to prepare the rGO / Fe3O4 electromagnetic shielding film. The preparation process is simple and easy to control, and raw materials are low in cost, easy to obtain and environmentally friendly; the graphene-based composite electromagnetic shielding material which is light in weight, high in strength, good in stability, good in flexibility and high in electromagnetic shielding efficiency can be prepared at present.

The invention belongs to the field of preparation of oxidized starch, and relates to a method for preparing oxidized starch by a mechanochemical method. Hydroxyl of corn starch is oxidized by hydrogen peroxide to generate modified starch with high carboxyl content, so that the modified starch has wider application. The preparation thought of a full bio-based mechanical method is adopted, the obtained modified starch has good economical efficiency, environmental safety and natural degradability, and the problems that an oxidized starch preparation process in the current market is large in environmental pollution, wastes resources, is tedious in process and the like are solved. According to the invention, biomass is used as a reaction raw material, is renewable and degradable, and accords with the green chemistry concept.

The invention discloses a preparation method of self-adhesive low-temperature-resistant multifunctional conductive gel as well as a product and application of the self-adhesive low-temperature-resistant multifunctional conductive gel, and belongs to the technical field of flexible electronic materials. The preparation method of the self-adhesive low-temperature-resistant multifunctional conductive gel comprises the following steps: adding an organic monomer into a sodium lignin sulfonate solution, adjusting the pH value to 2-4, then adding an initiator, and carrying out in-situ polymerization to obtain an LS / ICP mixed solution; dissolving the LS / ICP mixed solution and transition metal salt in a solvent to obtain a solution A; mixing the water-soluble polymer solution, acrylic acid, an initiator and a solvent to obtain a solution B; adding the solution A into the solution B, uniformly stirring and standing to obtain hydrogel, and soaking the hydrogel in a deep eutectic solvent to obtain the self-adhesive low-temperature-resistant multifunctional conductive gel. The self-adhesive low-temperature-resistant multifunctional conductive gel prepared by the invention has the advantages of good mechanical property, excellent self-adhesive property, high ionic conductivity, low temperature resistance, low preparation cost and the like.

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a double-carbon-coated bismuth ion doped sodium vanadium phosphate composite material, a preparation method and application thereof. The composite material is Na3BixV2-x (PO4) 3 / C (at) rGO, and x is more than or equal to 0.05 and less than or equal to 0.15. The preparation method of the composite material comprises the following steps: firstly, directly preparing Na3BixV2-x (PO4) 3 / C (at) rGO precursor powder by a one-step method; and calcining the Na < 3 > Bi < x > V < 2-x > (PO4) 3 / C (at) rGO precursor powder to obtain the Na < 3 > Bi < x > V < 2-x > (PO4) 3 / C (at) rGO composite material. The obtained composite material is used as a positive electrode material in a sodium-ion battery and has high reversible specific capacity, the electrochemical performance of the sodium-ion battery is greatly improved, and the battery is high in conductivity, stable in cycle performance and excellent in charge-discharge performance.

The invention belongs to the technical field of environmental protection and new energy, and discloses a cobalt-containing aerogel-loaded ruthenium monatomic catalyst as well as preparation and application thereof. The preparation method comprises the following steps: preparing cobalt-containing aerogel through a chemical precipitation method, preparing a ruthenium monatomic catalyst through a heat treatment method, uniformly grinding the cobalt-containing aerogel and the ruthenium monatomic catalyst, and carrying out heating treatment in an air atmosphere to obtain the cobalt-containing aerogel loaded ruthenium monatomic catalyst. The noble metal ruthenium in the obtained catalyst exists in a monatomic form, the content of the ruthenium metal is low, and the cobalt-containing aerogel has a special sheet structure. The material can expose a large number of catalytic active sites due to the special structure of single atoms and the larger surface area of aerogel. The obtained catalyst shows excellent catalytic activity and stability in an electro-catalysis nitrate reduction reaction.

The invention provides a solid beverage with a sleep promoting effect and an identification method thereof, and relates to the technical field of large health food. The beverage is prepared from medicinal and edible traditional Chinese medicinal materials such as radix puerariae, longan aril, mulberries, rhizoma polygonati, jujubes, lilies, wheat, chrysanthemums, red roses with double petals, spina date seeds and liquorice through scientific compatibility, the beverage is prepared by adopting modern pharmaceutical processes such as supercritical CO2 extraction and low-temperature and high-pressure homogeneous extraction, and the quality of a product is controlled and identified through a liquid-phase fingerprint technology. The invention provides a safe and effective product with homology of medicine and food for promoting sleep. By adopting extraction preparation technologies such as supercritical CO2 extraction and low-temperature high-pressure homogenization, the purity and activity of the components are ensured, and the modern pharmaceutical process is advanced; fingerprint analysis shows that the consistency of the relative retention time and the relative peak area of each component is good, and the similarity of chromatograms of all batches of products is more than 0.9998, so that the stability and the consistency of the products are ensured.

The invention relates to a preparation method of a high-purity graphite powder auxiliary cathode pressing block for glow discharge mass spectrometry test. According to the method, high-purity graphite powder is adopted as a matrix, a sample is efficiently, simply and rapidly prepared at low cost through two simple steps of sample loading and pressure applying, and compared with a traditional indium-assisted cathode determination method, the method is simple in sample preparation, low in cost, high in sample determination accuracy and safe in invented process and can be completed in the environment at normal temperature and normal pressure.

The invention discloses a feline calicivirus VP1 recombinant protein and application thereof. The amino acid sequence of the feline calicivirus VP1 recombinant protein is shown as SEQ ID No.1 in a sequence table. The neutralizing titers of the feline calicivirus positive serum prepared by adopting the recombinant protein as an antigen and different gene groups are all up to 1: 4096 times or above, the requirements of ELISA and IFA tests can be met, the feline calicivirus positive serum obtained after immunization of the prepared recombinant protein is good in purity, free of bacteria, free of mycoplasma and exogenous virus pollution, high in specificity and good in clinical application prospect. And the strain can react with strains of different evolution groups well, and has good broad spectrum. Positive serum prepared from the recombinant protein prepared by the invention can be used for quality control of different gene group cat calicivirus vaccines, such as specificity test, exogenous virus test, diagnostic detection and the like.

This invention relates to a mesoporous platinum@platinum-nickel core-shell framework nanowire and its preparation method, comprising the following steps: (1) uniformly mixing platinum precursor, nickel precursor, structure directing agent, and reducing agent with a first solvent, and performing a hydrothermal reaction to obtain Pt@Pt-Ni core-shell nanowires; (2) uniformly mixing the Pt@Pt-Ni core-shell nanowires with a second solvent and acetic acid, and performing an etching reaction to obtain etched mesoporous platinum@platinum-nickel core-shell framework nanowires. This invention employs a hydrothermal method, which is simple, reproducible, and allows for batch production with safety. Compared with traditional commercial platinum-carbon catalysts, the catalytic activity is greatly improved, the stability is greatly enhanced, and the production cost is reduced.

The invention discloses a firework powder mixing and filling production line in a paper tube, which comprises a paper tube cake positioning template conveyor, a reducing agent filling device, an oxidizing agent filling device, a bright bead filling device, an in-paper tube powder mixing and paper tube orbital transfer conveyor, a filler filling device, an opening tightening material filling device and a control device in sequence. A production method for mixed filling of firework powder in a paper tube comprises the steps that an oxidizing agent and a reducing agent or bright beads are loaded into a paper tube cake on a paper tube cake positioning template, powder is mixed in the paper tube, and a paper tube rail transfer conveyor enables a paper tube cake positioning template clamping mechanism to drive the clamped paper tube cake positioning template loaded with firework powder to ascend; the paper tube cakes are moved to a conveying device of the filler filling equipment while swinging by 180 degrees around the horizontal line or intermittently rotating by 180 degrees, the filler is filled into the paper tube cakes, and then the opening tightening materials are filled into the paper tube cakes. The firework powder mixing device has the advantages that firework powder is mixed in the paper tube, safety and reliability are achieved, and the quality and quantity of products are greatly improved.

The invention relates to a preparation method of hyaluronic acid oligosaccharide with controllable polymerization degree and a derivative thereof. The invention firstly provides a method for preparing the hyaluronic acid oligosaccharides and the derivatives thereof through cooperation of chondroitin synthase AuCS, hyaluronic acid synthase PmHAS and chondroitin lyase ODV-E66, the hyaluronic acid oligosaccharides or the derivatives thereof with any polymerization degree can be obtained, the defects of traditional physical or chemical degradation and enzymolysis methods are overcome, the diversity of oligosaccharide structures is enriched, and the application prospect is wide. And a foundation is laid for research on functions and characteristics of the hyaluronic acid oligosaccharides with different polymerization degrees and the derivatives of the hyaluronic acid oligosaccharides. Then, on the basis of the method, the hyaluronic acid oligosaccharide and the derivative thereof are prepared by utilizing a chondroitin synthase AuCS mutant, a hyaluronic acid synthase PmHAS mutant and chondroitin lyase ODV-E66, so that the synthesis efficiency and the yield of the product are greatly improved, and rapid, safe and large-scale preparation of the hyaluronic acid oligosaccharide and the derivative thereof is realized.

The present invention discloses a photocatalytic nanomaterial-microorganism hybrid and its preparation method and application. The preparation method comprises the following steps: adding graphene oxide to a mixed solution containing a water-soluble divalent cadmium salt, thiourea and polyvinyl pyrrolidone, performing a hydrothermal reaction, then washing and vacuum drying to obtain a CdX / RGO material; culturing Shewanella under aerobic conditions to obtain a bacterial solution; dispersing the CdS / RGO material in an anaerobic buffer to obtain a buffer A; centrifuging the Shewanella bacterial solution and discarding the supernatant, then dispersing the precipitate cells obtained by centrifugation into a buffer A, mixing and stirring to obtain a CdS / RGO / MR-1 material. The present invention prepares a novel hybrid of photocatalytic-biological synergistic and efficient hydrogen production, which can realize the efficient transfer of photogenerated electrons from the extracellular to the intracellular hydrogenase to promote the efficiency of light energy utilization and hydrogen production.

This vehicle body side structure (1) is provided with: a collision energy absorbing member (11) provided in a convex shape toward the outside in the vehicle width direction on the outer peripheral side in the vehicle width direction of a battery pack (5); and a recessed portion (13) which is formed in the side sill (3) in a recessed shape so as to secure a space between the collision energy absorbing member (11) and the side sill (3), and which delays the timing of contact between the side sill (3) and the collision energy absorbing member (11) when a collision load is input to the side surface of the side sill (3). Thus, a collision load input to the side sill (3) is transmitted to the floor cross member (7) before the side sill (3) is in contact with the collision energy absorbing member (11), and after the side sill (3) is in contact with the collision energy absorbing member (11), the collision energy absorbing member (11) absorbs collision energy, thereby reducing the load transmitted to the battery pack (5).

The application discloses a method for preparing fluorine-containing diphenylmethane compounds by using sulfur hexafluoride as a fluorination reagent, and belongs to the technical field of organic chemical synthesis. The preparation method comprises the following steps: (1) mixing a photocatalyst, a solvent and a reducing agent, and performing ultrasonic treatment to obtain solution A; mixing a reaction substrate and the solvent to obtain solution B; the photocatalyst is one or more of 4CzIPN, Ir[dF(CF3)ppy]2(dtbpy))PF6, 9-thioxanthone and 10-phenylphenothiazine; the reaction substrate is a compound with a structural formula of R1 and R2 are both H, alkoxy or halogen; (2) mixing the obtained solution A and solution B in a sulfur hexafluoride gas atmosphere, and performing reaction under blue light illumination, and the fluorine-containing diphenylmethane compounds are obtained. The method has the beneficial effects that the fluorine-containing diphenylmethane compounds are efficiently prepared by using sulfur hexafluoride as the fluorination reagent, and by selecting raw materials and catalysts with certain proportions; the reaction raw materials are cheap; the preparation process is safe, mild, has good substrate compatibility and high preparation efficiency.

The container manufacturing method is a method for manufacturing a composite container by making a film (FL) tightly adhered to the inner surface of a container (10) having a flange portion protruding outward from the periphery of the opening. The method includes the following steps: a step of receiving the container (10) in a concave first forming mold (20); a step of moving a second forming mold (30) to the first forming mold (20), the second forming mold (30) being configured to face the first forming mold (20) and having a protrusion (34) disposed on the outer periphery of the flange portion when the container (10) is received in the first forming mold (20); a step of holding the film (FL) between the first forming mold (20) and the second forming mold (30); a step of making the held film (FL) tightly adhered to the inner surface of the container (10) by means of a pressure difference; and a step of melting the film (FL) by means of the protrusion (34).

This invention addresses the problems of existing hydrogen-rich water dispensers, such as the inability to automatically replenish water, limited capacity for multiple users, and difficulty in troubleshooting safety issues. It provides a hydrogen-rich water dispenser device and its automatic control method. The raw water tank includes a level sensor and is connected to a water source via a solenoid valve, a booster pump, and a replenishment pump for automatic water replenishment. The hydrogen-rich water tank also contains a level sensor and is connected to a water source via a solenoid valve and a replenishment pump for automatic water replenishment. An electrolytic cell, a flow sensor, a circulation pump, a fan, a gas-liquid separator, and a gas-liquid mixing pump are installed between the raw water tank and the hydrogen-rich water tank. The hydrogen-rich water tank is connected to a hydrogen elimination chamber to eliminate excess hydrogen. The hydrogen-rich water dispenser of this application features automatic water replenishment, one-button start / stop, one-button water production, and can provide water level alarms, hydrogen elimination functions, fault alarms, and power-off protection.

The present application relates to a kind of reversible immunomagnetic beads for quickly separating target cells and its preparation method. Specifically, the present application provides a kind of reversible immunomagnetic beads, which includes magnetic carrier, affinity ligand and the connecting arm of the connection between the two, wherein the connecting arm contains a nucleotide sequence that can be specifically recognized by enzyme cutting, preferably containing deoxyinosine (dI) base.The present application also provides a kit comprising the magnetic beads and specific cleavage enzyme (such as endonuclease V).The magnetic beads of the present application can be cleaved by enzyme to achieve mild and rapid dissociation of the magnetic beads and target cells, with high separation efficiency and good cell viability, solving the problem of cell damage caused by irreversible binding of traditional immunomagnetic beads.The present application is simple to operate, does not require complex equipment, and the separated cells can be directly used for in vitro expansion, differentiation or cell therapy, and has wide research and clinical application prospects.

The invention discloses equipment for preparing glass fibers from waste glass, and relates to the field of glass fiber preparation, and the equipment for preparing the glass fibers from the waste glass comprises a cleaning mechanism, a fiber clamping mechanism, a fiber winding mechanism and a discharging hole; the cleaning mechanism can automatically clean the fiber outlet hole, firstly, manual operation is avoided, secondly, the manual operation cannot clean the fiber outlet hole before yarn outlet every time like the mechanism, and the cleaning of the mechanism can enable the cleaning of the fiber outlet hole to achieve a better yarn outlet effect. The cellosilk clamping mechanism can automatically complete the action of drawing the cellosilk, manpower is saved, the working efficiency is improved, the cellosilk winding mechanism can be matched with the former two mechanisms to autonomously clamp the cellosilk and wind the cellosilk, the overall efficiency of the equipment is high, the two mechanisms are linked with each other, the previous imperfect operation is changed, and the working efficiency and the product quality are improved.

The invention discloses an aniline synthesis method based on acetylenic ketone and allylamine, which comprises the following steps: by taking acetylenic ketone and allylamine as reactants, adding the acetylenic ketone and allylamine and a polar organic solvent into a reaction bottle, mixing, sealing the reaction bottle, and carrying out stirring reaction for 12-24 hours at 80-160 DEG C under anhydrous and anaerobic conditions; and separating and purifying to obtain a corresponding aniline product. The method has the characteristics of simple and easily available substrates, mild reaction conditions, wide substituent compatibility and the like, can efficiently and conveniently synthesize the polysubstituted aniline, enlarges the preparation scale, has good industrial practicability, and has extremely high application value in the fields of drug synthesis and the like.

The invention discloses a porous carbon / vanadium nitride composite electrode material and a preparation method and application thereof, and belongs to the technical field of electrode materials. The preparation method of the porous carbon / vanadium nitride composite electrode material comprises the following steps: taking an amino-containing interpenetrating network polymer as a precursor, removing moisture, and carrying out impregnation complexation with vanadium oxide sol to obtain an impregnated compound after impregnation is completed; and performing primary pyrolysis on the impregnated compound at the temperature of 280-350 DEG C in a protective atmosphere, and then performing secondary pyrolysis at the temperature of 700-900 DEG C to prepare the porous carbon / vanadium nitride composite electrode material. During preparation, a reducing atmosphere does not need to be introduced, the preparation environment is safe, and the prepared porous carbon / vanadium nitride composite electrode material is excellent in cycle life.

The invention provides injectable and self-healing oxidized nicandra physaloides polysaccharide-carboxymethyl chitosan composite hydrogel as well as a preparation method and application thereof, and belongs to the technical field of hydrogel material preparation. The composite hydrogel is successfully prepared by taking two natural components of nicandra physaloides polysaccharide and carboxymethyl chitosan as raw materials, the gelation time of the composite hydrogel is only 5-10 seconds, and the need of rapid hemostasis of wounds can be met. The final oxidized nicandra physaloides polysaccharide content of the hydrogel prepared by the method is 0.5%, the carboxymethyl chitosan content is 1%, and the hydrogel with stable performance can be prepared by polysaccharide with lower content. According to the prepared hydrogel, the mass ratio of the oxidized nicandra physaloides polysaccharide to the carboxymethyl chitosan is 1: 2, so that the hydrogel not only has a very good gel effect, but also has excellent mechanical properties, good stability and short gelling time, does not have cytotoxicity when being used as a wound dressing, is a rare and precious hydrogel dressing with natural active ingredients, and has a very good application prospect. The requirements of wound hemostasis and the like can be met.

This invention discloses a Bi₂O₃ / V₂C material, its preparation method, and its applications. The Bi₂O₃ / V₂C material is synthesized from Bi salt and V₂C through a hydrothermal reaction and calcination. The elemental molar ratio between Bi salt and V₂C is Bi:V = 14~300:1. By weight, the ratio between Bi salt and V₂C is m(V₂C):m(Bi salt) = 0.1%~2%:1. This invention uses the oxide corresponding to the Bi salt as the main catalyst and introduces V₂C as a co-catalyst. The resulting material exhibits improved catalytic performance, requires a lower V₂C dosage, and can catalytically degrade malachite green at a degradation rate of over 90%.

The utility model discloses an ammunition mold plate which comprises a mold plate body, a plurality of containing spaces are formed in the mold plate body, and the shape of the containing spaces is matched with the shape of ammunition to be manufactured; and the mold plate body is made of a conductive silicone rubber material. According to the ammunition mold plate, the mold plate body is made of the conductive silicone rubber material, in this way, after flammable and explosive ammunition and other products are manufactured through the ammunition mold plate, the manufacturing process is safe, static electricity cannot be generated when the products are manufactured and taken out, and ammunition manufacturing is safer.

The invention provides a fluorine-containing polymer for spleen selective nucleic acid delivery, a polymer lipid hybrid nanoparticle and a preparation method and application of the polymer lipid hybrid nanoparticle. The preparation method of the fluorine-containing polymer for spleen selective nucleic acid delivery comprises the step of carrying out ring-opening addition reaction on alkylene oxide, fluorine-substituted alkylene oxide and polyethyleneimine to prepare the fluorine-containing polymer. The preparation method of the fluorine-containing polymer is simple, mild in condition and high in finished product yield; the obtained fluorine-containing polymer is used for preparing polymer lipid hybrid nanoparticles, nucleic acid can be specifically delivered to the spleen and plays a role, and the fluorine-containing polymer has a good transfection effect on the dendritic cells of the spleen and also has good biological safety.

A vehicle body side structure (1) is provided with a side sill (3) extending in the vehicle length direction, and a battery pack (5) disposed further toward the vehicle width direction inner side than the side sill (3), the vehicle width direction outer peripheral side of the battery pack (5) is provided with a collision energy absorbing member (11) provided in a convex shape toward the vehicle width direction outer side, and the collision energy absorbing member (11) is provided in a convex shape toward the vehicle width direction outer side. The collision energy absorbing member (11) is made of a steel plate having a tensile strength of 270-340 MPa and a plate thickness of 1.0-1.4 mm, and when a collision load is input from the outside in the vehicle width direction to the side surface of the side sill (3), the collision energy absorbing member (11) is deformed and absorbs collision energy after the side sill (3) deformed by the input collision load comes into contact with the collision energy absorbing member (11). Therefore, the load transmitted to the battery pack (5) is reduced.

The invention discloses preparation and application of a plant extract for preventing and treating non-alcoholic steatohepatitis. The preparation method comprises the following steps: extracting and concentrating boxthorn leaves to serve as a loading solution; and separating and purifying the loading solution by using the synthesized macroporous resin to obtain the boxthorn leaf total flavone extract, the total flavone content is greater than 60%, and the yield is greater than 90%. The method for preparing the extract for preventing and treating the non-alcoholic steatohepatitis is green and environment-friendly, the process route is simple, and animal experiments prove that the obtained extract has a good drug effect on the non-alcoholic steatohepatitis and can be used for developing health-care foods, functional foods and new drugs.

The application discloses a key amino acid induced new crystal form of linagliptin based on protein-drug interaction structure mining and a preparation method thereof; and the technical scheme is that key amino acids are introduced into a solvent crystallization system of linagliptin to induce five new crystal forms of linagliptin; the preparation method does not need to use a large amount of organic solvents, has the characteristics of being simple, precise and efficient, has strong crystal form regulation capacity, is energy-saving, environment-friendly and safe, and is easy to realize green industrial production.