5results about How to "Low purity requirement" patented technology

This invention provides the application of a mixture of methylstyrene with high para-isomer content in the preparation of polystyrene substitute copolymers, belonging to the field of polymer material synthesis technology. This invention is the first to directly utilize a low-cost mixture of methylstyrene isomers to replace high-purity styrene. Through a "boiling-condensation" cycle in the fluidized bed polymerization process, efficient and constant-temperature heat dissipation is achieved, effectively overcoming the heat transfer difficulties and temperature runaway risks of traditional bulk polymerization. This facilitates control of the polymerization mechanism and yields random copolymers with a narrow molecular weight distribution and mechanical properties comparable to general-purpose polystyrene. This method is simple and controllable, significantly reduces raw material costs, and combines economic benefits with environmental value. The resulting copolymers can be used in general plastics, packaging materials, and other fields.

The application relates to a purification method of a bifluorosulfonylimide lithium salt, comprising the following steps: modifying a polytetrafluoroethylene film by using plasma and formic acid, immersing the polytetrafluoroethylene film in bifluorosulfonylimide acid after the modification is completed, heating and drying to obtain a modified polytetrafluoroethylene film; dispersing lithium carbonate in dimethyl carbonate, then adding bifluorosulfonylimide acid, obtaining a reaction liquid after the reaction is completed, filtering the reaction liquid to obtain a filtrate, concentrating the filtrate once to obtain a bifluorosulfonylimide lithium electrodialysis crude solution; using the modified polytetrafluoroethylene film to purify the bifluorosulfonylimide lithium electrodialysis crude solution by electrodialysis, then concentrating and crystallizing the obtained electrodialysis liquid to obtain battery-grade bifluorosulfonylimide lithium. The method provided by the application can reduce the purity requirement of raw material lithium carbonate from battery grade to industrial grade, which is beneficial to industrial production.

This invention discloses a method for preparing polyglycolic acid (PGA) and the PGA obtained by this method, relating to the field of PGA preparation technology. The method comprises: prepolymerizing glycolide in the presence of a catalyst to obtain a suspension; separating and removing insoluble matter from the suspension; and then performing a polymerization reaction to obtain the PGA. This invention uses low-purity glycolide as a raw material. After adding a catalyst, impurities undergo a certain degree of prepolymerization at a low temperature, allowing them to precipitate automatically. The precipitate is then separated and removed to obtain high-purity glycolide, which is then polymerized in situ at a higher temperature (retaining the initially added catalyst) to obtain high-molecular-weight PGA. This preparation method has low requirements for raw material purity, is simple and effective, and reduces the cost of PGA preparation to a certain extent.

The present application relates to a kind of poly-doped-ammonium intercalation vanadium oxide material and its preparation method and purposes, the preparation method includes the following steps: (1) the alkali leaching solution of sodium calcined vanadium residue is added to desilication agent and carries out desilication reaction, obtains desilication leaching solution;(2) the desilication leaching solution in step (1) is added to ammonium salt and carries out precipitation reaction, obtains precursor;(3) the precursor in step (2) is sequentially carried out drying treatment, calcination treatment, and the poly-doped-ammonium intercalation vanadium oxide material is prepared.The preparation process of the present application reduces the requirement for vanadium species purity in preparation process on the one hand by using the alkali leaching solution of vanadium residue as raw material, on the other hand, the associated excellent impurities therein serve as a doping source for the preparation process, making the preparation process more simplified, and the zinc ion battery prepared from the obtained vanadium oxide material has excellent electrochemical performance.

The application belongs to the field of new energy, and discloses a synthesis method of lithium tetrafluoroborate, which comprises the following steps: step 1: adding lithium halide into a non-aqueous organic solvent, and introducing boron trichloride to obtain a solution containing lithium haloborate; and step 2: introducing hydrogen fluoride into the solution obtained in step 1 to obtain a solution containing lithium tetrafluoroborate. The method is synthesized by using a solvent method, and any available lithium halide and boron trichloride are used to react to obtain an intermediate product, and then the intermediate product is fluorinated to obtain lithium tetrafluoroborate, and various lithium halides can be selected to realize the scheme of the application, the raw materials are rich in selectivity, and the production cost is significantly reduced.