Water-in-CO_2 Emulsions:Reaction Vessels for the Production of Tetra-Ethyl Pyrone

摘要

Water-in-CO2 (W/C) emulsions formed using a nickel Triton X-100 surfactant complex (Ni-surfactant) were used as microreactors for the carbon-carbon coupling reaction between hex-3-yne and CO2 to produce tetra-ethyl pyrone (TEP).The structure of the product,which was isolated in the CO2 phase,was determined using gas chromatography mass spectrometry (GC-MS) and infrared spectroscopy.The Ni-surfactant acted as both an emulsion forming agent and a water soluble catalyst for this carbon-carbon coupling reaction.The optimum yield of TEP was determined to be 69% after 72 h,at a temperature of 70 deg C and a pressure of 206 bar.The ease with which the emulsion could be collapsed allowed the facile separation of products from the catalyst and any unreacted starting materiál.Product selectivity in the W/C emulsions was found to be greater than that obtained using conventional organic methodologies.