アクリロニトリルの液相直接合成法に関する研究 (第8報) : アセチレンよりモノビニルアセチレン合成反応のNiewland触媒におけるNH4Clの濃度について

概要

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In the reaction for formation of monovinylacetylene (MVA) from acetylene, the Niewland catalyst showed catalytic activity by addition of NII, Cl to CuCl. Although it has been considered that the maximum catalytic activity is obtainable when it has a constituent of CuC1.NH4Cl, the catalytic activity of CuClNH4Cl is the greatest when it has the concentration up to 400% of NH4Cl in water at 90°C but the maximum activity shifted towards the catalyst containing more CuCI than CuCl. NH2Cl in case of the concentration of NH4Cl exceeded 400%. In other words, the limit of concentration of NH4Cl in water for showing the maximum catalystic activity is up to 40%. However, the above limit of concentration is disappeared by reacting at low temperature such as at 40°C or by adding dimethyl sulfoxide (DMSO) in the reaction at 90°C in order to increase the saturated concentration of acetylene in the catalyst and to show the maximum catalytic activity of CuCl. NH4Cl even though the concentration of NH4Cl in CuCl. NH4Cl is reached above 40%. The presence of the limit of concentration is considered to be due to result of two counter-acting factors of showing positive effect by the increase in concentration of complex salt with the increase of NH4Cl in water and the negative effect by the decrease in concentration of acetylene.