Study on catalytic synthesis of tri(2-ethylhexyl) citrate with copper methanesulfonate

Copper methanesulfonate was synthesized and was used as the catalyst in the esterification of citric acid with 2-ethylhexanol.The effects of reaction temperature,amount of catalyst and alcohol/acid molar ratio have been investigated.The yield can be over 98% under the optimum conditions that molar ratio of 2-ethylhexanol to citric acid is 1.08 ∶0.3;amount of catalyst is 0.30%(molar percentage of citric acid) and reaction temperature is 120～130 ℃,reaction pressure is vacuum.The catalyst can be reused by simple phase-separation after reaction.It is used repeatedly for 5 times without obvious loss of activity and with the yield still over 90.0%.