3results 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 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].