For the determination of the caproic acid value, the color change of the indicator is not obvious; can another indicator be used?
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For the determination of the caproic acid value, the color change of the indicator is not obvious; can another indicator be used? The method involves using phenolphthalein, but in practice the color change is not very noticeable. Can another indicator be used as a substitute? Can bromocresol green methyl red indicator be used?
Determining the acid value of organic solvents generally involves non-aqueous titration, and it is normal for the color change of some indicators to not be very noticeable. First, you can determine the endpoint by comparing the blank with the blank titrated to the endpoint. Or consult some materials to select an appropriate indicator that can be used in non-aqueous solvents; this requires you to look up relevant information on your own. Another method for indicating the endpoint is potentiometric titration using a pH electrode; this method is used for titrating samples for which color changes cannot be utilized.