Lanthanum methanesulfonate is synthesized and is 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 hav...Lanthanum methanesulfonate is synthesized and is 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 products are analyzed by means of FT-IR.The yield can be over 97.5% under the optimum conditions that molar ratio of 2-ethylhexanol to citric acid is 3.60∶1,amount of catalyst is 0.25 %(molar percentage of citric acid),reaction temperature is 120℃~130℃ and operation in 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%.展开更多
目的建立LC-MS/MS法检测2-脱氧-D-核糖中基因毒性杂质甲磺酸甲酯和甲磺酸乙酯的方法。方法选用C18色谱柱(以十八烷基硅烷键合硅胶为填充剂,250 mm×4.6 mm,5μm),以甲醇-水(体积比30∶70)为流动相,流速为1.0 m L·min-1,分...目的建立LC-MS/MS法检测2-脱氧-D-核糖中基因毒性杂质甲磺酸甲酯和甲磺酸乙酯的方法。方法选用C18色谱柱(以十八烷基硅烷键合硅胶为填充剂,250 mm×4.6 mm,5μm),以甲醇-水(体积比30∶70)为流动相,流速为1.0 m L·min-1,分流比为30%,柱温为40℃,进样量为10μL。采用APCI离子源检测扫描方式负离子模式检测。结果甲磺酸甲酯和甲磺酸乙酯质量浓度在20~200μg·L-1内与峰面积线性关系良好,甲磺酸甲酯和甲磺酸乙酯的检测限为4μg·L-1,定量限为10μg·L-1,甲磺酸甲酯和甲磺酸乙酯的回收率分别为104.8%(RSD=7.93%,n=9)和101.0%(RSD=5.97%,n=9)。结论本方法灵敏、专属性强,适用于2-脱氧-D-核糖中基因毒性杂质甲磺酸甲酯和甲磺酸乙酯的检测。展开更多
文摘Lanthanum methanesulfonate is synthesized and is 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 products are analyzed by means of FT-IR.The yield can be over 97.5% under the optimum conditions that molar ratio of 2-ethylhexanol to citric acid is 3.60∶1,amount of catalyst is 0.25 %(molar percentage of citric acid),reaction temperature is 120℃~130℃ and operation in 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%.
文摘目的建立LC-MS/MS法检测2-脱氧-D-核糖中基因毒性杂质甲磺酸甲酯和甲磺酸乙酯的方法。方法选用C18色谱柱(以十八烷基硅烷键合硅胶为填充剂,250 mm×4.6 mm,5μm),以甲醇-水(体积比30∶70)为流动相,流速为1.0 m L·min-1,分流比为30%,柱温为40℃,进样量为10μL。采用APCI离子源检测扫描方式负离子模式检测。结果甲磺酸甲酯和甲磺酸乙酯质量浓度在20~200μg·L-1内与峰面积线性关系良好,甲磺酸甲酯和甲磺酸乙酯的检测限为4μg·L-1,定量限为10μg·L-1,甲磺酸甲酯和甲磺酸乙酯的回收率分别为104.8%(RSD=7.93%,n=9)和101.0%(RSD=5.97%,n=9)。结论本方法灵敏、专属性强,适用于2-脱氧-D-核糖中基因毒性杂质甲磺酸甲酯和甲磺酸乙酯的检测。