4results about How to "Moderate reactivity" patented technology

This invention discloses a method for synthesizing cefotiam, using 7-aminocephalosporanic acid (7-ACA) as the parent nucleus and introducing a 4-dimethylaminopyridine-dimethyl carbonate composite catalytic system. The reaction is carried out in a one-pot process involving 3-position nucleophilic substitution, 7-position amidation, and simultaneous deprotection in a green mixed solvent of ionic liquid [BMIM]BF₄-water with 1-(2-dimethylaminoethyl)-1H-5-mercapto-tetrazole and compound I. This method simplifies the process, improves selectivity, produces a high-purity product with stable yield, and is suitable for industrial production.

The application belongs to the technical field of polishing pads, and particularly relates to a polishing pad end point inspection window and a preparation method and application thereof. The preparation method comprises the following steps: reacting aliphatic isocyanate and polyester polyol to prepare a prepolymer, mixing the prepolymer with a curing agent, vacuum defoaming, and vulcanization. The polyester polyol is polycaprolactone diol obtained by taking polycarbonate diol as a starter and modifying caprolactone. The molecular weight of the polycarbonate diol is 200-400, and the molecular weight of the polyester polyol is 1000-3000. The curing agent comprises dihydric alcohol and alicyclic polyamine. The alicyclic polyamine has a branched chain with a carbon atom number of less than or equal to 4, and the functionality of the alicyclic polyamine is greater than or equal to 2. The polishing pad end point inspection window prepared by the preparation method has high light transmittance, and the light transmittance and hardness attenuation are reduced.

The invention relates to the technical field of agricultural planting, in particular to a polyurethane modified culture medium and a preparation method and application thereof.The polyurethane modified culture medium is prepared from, by volume, 100 parts of culture medium with the average particle size being 0.05-10 mm; 0.5 to 10 parts by weight of an MDI type polyurethane prepolymer; 1 to 10 parts by weight of a TDI type polyurethane prepolymer; 75 to 100 parts by weight of water; wherein when the weight measurement unit is g, the volume measurement unit is mL; wherein the NCO content of the MDI type polyurethane prepolymer is marked as a%, the NCO content of the TDI type polyurethane prepolymer is marked as b%, a and b meet the condition that a-b is larger than or equal to-3 and smaller than or equal to 3, the shaping effect, porosity and water retention and maintenance capacity of the polyurethane modified culture medium are obviously improved, and the hardness is moderate.

The invention discloses a preparation method of an InP quantum dot based on silicon-based phosphine salt and the InP quantum dot prepared by the preparation method. The preparation method comprises the following steps: stirring and reacting an indium precursor, silicon-based phosphonium salt MP (TMS) 2 and a selectively added first zinc precursor in a solvent in an inert atmosphere at 150-220 DEG C to obtain a solution containing an InP nanocrystal nucleus, then heating to 240-310 DEG C, adding one or more of a second zinc precursor, a selenium precursor and a sulfur precursor, coating the InP nanocrystal nucleus with a shell layer, and carrying out vacuum drying to obtain the indium-selenium-sulfur-doped InP nanocrystal. The shell layer contains one or more of a zinc element, a selenium element and a sulfur element; m in the silicon-based phosphine salt MP (TMS) 2 is K, Na or Li, and TMS is [-Si (CH3) 3].