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
In order to provide a new way for waste cooking oil(WCO) resource utilization, several diester derivatives were obtained from WCO through a three-step chemical modifications, viz.: transesterification, epoxidation and...In order to provide a new way for waste cooking oil(WCO) resource utilization, several diester derivatives were obtained from WCO through a three-step chemical modifications, viz.: transesterification, epoxidation and oxirane ring opening with carboxylic acids. The effects of the chain length of side chain groups on the viscosity, acid value, low temperature fluidity, thermo-oxidative stability, tribological properties and surface tension of diester derivatives were investigated. The results showed that increasing the chain length of side chain groups had a positive influence on the viscosity, viscosity index, acid value, pour point, friction coefficient and wear scar diameter along with a negative influence on the oxidation onset temperature, volatile loss, insoluble deposit, maximum non-seizure load and surface tension. These diester derivatives exhibited improved physicochemical and tribological properties that make themselves promising environmentally friendly biolubricant basestocks.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.
基金the financial support from the Natural Science Foundation of Chongqing(Project No.cstc2014jcyj A90013)
文摘In order to provide a new way for waste cooking oil(WCO) resource utilization, several diester derivatives were obtained from WCO through a three-step chemical modifications, viz.: transesterification, epoxidation and oxirane ring opening with carboxylic acids. The effects of the chain length of side chain groups on the viscosity, acid value, low temperature fluidity, thermo-oxidative stability, tribological properties and surface tension of diester derivatives were investigated. The results showed that increasing the chain length of side chain groups had a positive influence on the viscosity, viscosity index, acid value, pour point, friction coefficient and wear scar diameter along with a negative influence on the oxidation onset temperature, volatile loss, insoluble deposit, maximum non-seizure load and surface tension. These diester derivatives exhibited improved physicochemical and tribological properties that make themselves promising environmentally friendly biolubricant basestocks.
