2 results about "Tetrabromoethane" patented technology

The invention discloses a low-chlorine low-alkene tetrabromoethane synthesis method in the technical field of chemical synthesis, which comprises the following steps: synthesizing tetrabromoethane in a gas-liquid microporous continuous reactor by using a mixed gas of acetylene and nitrogen and bromine; a rotatable membrane assembly is arranged in a gas-liquid mixing through cavity of the gas-liquid microporous continuous reactor, the membrane assembly comprises a microporous membrane, a bromine inlet is connected with the gas-liquid mixing through cavity, a mixed gas inlet is connected with an inner side cavity of the microporous membrane, the gas-liquid mixing through cavity is connected to a tetrabromoethane collecting through cavity through a plurality of micropipes, and the tetrabromoethane collecting through cavity is connected with a gas inlet of the gas-liquid microporous continuous reactor. The reaction liquid leaves the device through a reaction liquid outlet, and the high-purity tetrabromoethane is obtained through alkali washing, water washing and adsorption of the reaction liquid after the reaction. Acetylene passes through membrane holes in the form of microbubbles, and forms a thickness lt with bromine on the surface of the membrane; a 10 [mu] m transient liquid film reaction zone; further addition reaction is completed in the microtube. The content of inorganic chloride, organic chloride and halogenated olefin in the finished product is low, and the quality of the product can be improved.

This invention discloses a method for preparing cis-1,2-dibromoethylene based on steric hindrance, belonging to the field of technical organic synthesis. The method includes the following steps: (a) providing reactors A and B connected in series. Bromine is added to reactor A, and a solvent and configuration-selective catalyst are added to reactor B. This invention employs a series reactor system. Under the synergistic effect of a copper / crown ether composite catalyst and ultraviolet light, a highly selective addition reaction of acetylene with bromine is achieved by controlling the solvent system, reaction temperature, and material ratio. Using acetonitrile or perfluoroalkane as solvent, and copper chloride and crown ethers (such as 15-crown-5) as catalysts, the reaction is carried out at 30-80℃ under 200-400nm ultraviolet light. The selectivity of cis-1,2-dibromoethylene is ≥95%, which has advantages such as mild reaction conditions, solvent recyclability, and suitability for industrial production. Furthermore, the cis selectivity is improved to ≥95%; the content of the byproduct tetrabromoethane is <0.5%; and the solvent recovery rate is >98%.