化学滴定法测定岩心中的总有机酸含量

用返滴定法测定了柴达木盆地部分岩心中的总有机酸含量 ,考察了萃取溶剂、煮沸时间、滴定方式等因素对测定结果的影响。实验结果表明 ,岩心颗粒越小 ,萃取率越高 ,实验中可将岩心研磨至 37μm(40 0目 )。体积比为3∶7的苯乙醇混合溶剂的萃取效果好于乙醇、氯仿乙醇。加热煮沸时间对有机酸的测定结果影响不大 ,加热煮沸 5min即可达到萃取平衡。柴达木盆地有机酸的酸值波动较大 ,为 0 .1 954～ 0 .2 336mmol/g。与直接滴定法相比较 ,返滴定法测定具有萃取率高、终点易观察、结果重复性好等优点。

Determination of total content of carboxylic acids in rock core with titration

The total content of carboxylic acids in rock core of Qaidam Basin was determined with back titration. The measured values are in the range of 0.2336 mmol/g to 0.1954 mmol/g. The influence of extracting solvent, boiling time and titration pattern on the extraction of the organic acids was investigated. The better experimental conditions were obtained. The diameter of rock core is 400 meshes, and volume ratio of benzene to alcohol is three to seven, and boiling time is five minutes. The back titration method has many advantages over the direct titration method.It has high extraction rate and precision, and the titration point is easy to be found.