4 results about "Triethyl orthoformate" patented technology

This application relates to a UV-3 ultraviolet absorber and its preparation method, belonging to the field of chemical synthesis technology. The preparation method employs a one-pot process, in which benzocaine reacts with triethyl orthoformate in xylene solvent. This step utilizes reactive distillation coupling control, continuously removing the generated alcohol distillate through a distillation separation device to promote reaction equilibrium shift, obtaining a xylene solution of the intermediate NET. Subsequently, the solution is heated to a reaction temperature of 135–145°C, and benzyl chloride is added dropwise for N-alkylation, while a tail gas absorption device absorbs byproduct gases. The reaction slurry is then cooled for crystallization, solid-liquid separation, and drying to obtain the UV-3 product. This invention simplifies the production process through a one-pot process, avoids the use of toxic DMF solvent, and solves the technical problem of raw material residues leading to subsequent side reactions in the one-pot process through reactive distillation coupling control, resulting in a final product with high purity and high yield.

This invention proposes a method for preparing dehydroepiandrosterone (DHEA), comprising the following steps: S1, dissolving 4-androstenedione in acetic anhydride to obtain a first material, which is then pumped separately into an acetylation microchannel reactor with quaternized GO-phosphotungstic acid catalyst supported on the inner wall for reaction with acetyl chloride; S2, mixing triethyl orthoformate with anhydrous ethanol to obtain a second material, which is then pumped separately into a ketal microchannel reactor with niobium oxide / γ-CD-phosphotungstic acid catalyst supported on the inner wall of the ketal microchannel reactor; S3, dehydrating the effluent from step S2 and adjusting the pH to 7-8, then pumping separately into a reduction microchannel reactor with an ethanol solution containing sodium borohydride for reduction reaction; S4, adding hydrochloric acid to the effluent from step S3 and adjusting the pH to 2-3 to obtain a hydrolysate; evaporating the solvent from the hydrolysate, filtering and drying to obtain DHEA. The supported heteropolyacid composite membrane used in this invention exhibits high catalytic efficiency, high yield, and excellent quality.

The application belongs to the technical field of medicine synthesis, and particularly relates to a gemigim intermediate compound and a preparation method thereof. The gemigim new intermediate compound is obtained by reacting alpha-cyanoacetamide, triethyl orthoacetate and triethyl orthoformate as starting materials. The new intermediate is cyclized to obtain a gemigim key intermediate compound 3-cyano-4-methoxy-2(1H)-pyridinone. The new intermediate synthesis method provided by the application is simple, triethyl orthoformate is used as a 'one-carbon unit' donor, the reagent only produces ethanol in the cyclization process, the use of DMF-DMA can be effectively avoided, and then the generation of dimethylamine gas or its acetate salt is avoided, so that the reaction operation is safer and more environmentally friendly.

This invention relates to the field of refrigerants, specifically to a mixed refrigerant and its preparation method. By weight, the refrigerant comprises 85-95 parts of a basic refrigerant, 1-5 parts of a flame retardant, 1-10 parts of a lubricating oil, and 0.1-0.5 parts of a stabilizer. The basic refrigerant is a mixture of R32, R1234ze(E), and R1234yf in a mass ratio of (18-28):(45-60):(15-25). The stabilizer is a mixture of triethyl orthoformate, triphenyl phosphite, and methylbenzotriazole in a mass ratio of (0.1-0.15):(0.1-0.15):(0.15-0.2). This refrigerant has a low GWP, good flame retardant properties, and good stability.