Polyol esters of lubricating oil were synthesized by dipentaerythritol（di-PE）with n-Valeric acid,n-Hexanoic acid,n-Heptanoic acid and n-Caprylic acid（C5 to C8 carboxylic acids）under microwave radiation.The best sy...Polyol esters of lubricating oil were synthesized by dipentaerythritol（di-PE）with n-Valeric acid,n-Hexanoic acid,n-Heptanoic acid and n-Caprylic acid（C5 to C8 carboxylic acids）under microwave radiation.The best synthetical conditions of di-PE with C5 to C8 carboxylic acids were investigated under microwave radiation.The best molar ratio of C5 to C8 carboxylic acids vs di-PE was 8∶1.The best microwave power was between 300W and 320W.The best composite catalyst was selected,and the ratio of composite catalyst（vitriol oil vs P-Toluene Sulphonic acid）was from 1∶2.5 to 1∶3.0.The esterifiable temperatures of dipentaerythritol hexa-valerianate,dipentaerythritol hexa-caproate,dipentaerythritol hexa-heptylate,dipentaerythritol hexa-caprylate were respectively 114℃～116℃、126℃～128℃、134℃～136℃、140℃～142℃.The yields were at least 93% within 9～10min.The viscosity coefficients were determined by Ubbelohde viscosimeter at 31℃±0.05℃ and were respectively 66.4mm2/s,70.8mm2/s,75.3mm2/s,78.1mm2/s.With the increase of carbon atom number of carboxylic acids,the esterifiable temperatures and viscosities of 3a-3d gradually went up.The structures of 3a-3d were identified by 1H NMR,13C NMR and IR spectra.The refractive indexs of 3a-3d were determined with ZWA-J refractometer.This method is fast,efficient and high-yielding,and may provide a new researchful orientation for traditional technology improvement of esters lubricating oil.展开更多
文摘Polyol esters of lubricating oil were synthesized by dipentaerythritol（di-PE）with n-Valeric acid,n-Hexanoic acid,n-Heptanoic acid and n-Caprylic acid（C5 to C8 carboxylic acids）under microwave radiation.The best synthetical conditions of di-PE with C5 to C8 carboxylic acids were investigated under microwave radiation.The best molar ratio of C5 to C8 carboxylic acids vs di-PE was 8∶1.The best microwave power was between 300W and 320W.The best composite catalyst was selected,and the ratio of composite catalyst（vitriol oil vs P-Toluene Sulphonic acid）was from 1∶2.5 to 1∶3.0.The esterifiable temperatures of dipentaerythritol hexa-valerianate,dipentaerythritol hexa-caproate,dipentaerythritol hexa-heptylate,dipentaerythritol hexa-caprylate were respectively 114℃～116℃、126℃～128℃、134℃～136℃、140℃～142℃.The yields were at least 93% within 9～10min.The viscosity coefficients were determined by Ubbelohde viscosimeter at 31℃±0.05℃ and were respectively 66.4mm2/s,70.8mm2/s,75.3mm2/s,78.1mm2/s.With the increase of carbon atom number of carboxylic acids,the esterifiable temperatures and viscosities of 3a-3d gradually went up.The structures of 3a-3d were identified by 1H NMR,13C NMR and IR spectra.The refractive indexs of 3a-3d were determined with ZWA-J refractometer.This method is fast,efficient and high-yielding,and may provide a new researchful orientation for traditional technology improvement of esters lubricating oil.
