×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Conductivity as a method for determining the solute concentration on apolar solvent: is it possible?

Conductivity as a method for determining the solute concentration on apolar solvent: is it possible?

Conductivity as a method for determining the solute concentration on apolar solvent: is it possible?

(OP)
I'm trying to find a relatively simple method for determining the concentration (up to at least 1% of accuracy) of an organic compound in methylciclohexane from a liquid-liquid extraction in order to provide standard crystallization conditions downstream (many recicle streams from one batch to another turns this crystallization in a living hell; eliminate then is out of cogitation).
I already have conductivity meters that act separating the organic phase from the aqueous. The range of conductivity is very broad (13 to +1000 mSiemens), and the organic phase have a conductivity around 19 mS on average, oscillating between 13 and 26 mS. An oscillation of 3 or even 6 mS can be observed even on operation stops, so i know for sure that the conductivity meters calibrated for this rangeare could not be used to build a curve correlating the concentration to the accuracy desired.

The question is: it is a fact that even apolar media presents some conductivity, and this conductivity is a function of the species and their concentration in the media (the temperature is kept constant), so a conductivity analysis calibrated for a smaller range (like 0-30 mS) would have the sensibility for detecting solute small concentration variations? I could request a lab study for creating a curve fiting this data if it correlates to concentration in a significative and measurable way.

If not, what other methods do you suggest for measuring organic solutes concentrations on organic solvents in industrial equipment?

Thanks.

RE: Conductivity as a method for determining the solute concentration on apolar solvent: is it possible?

If this organic solute is an optical isomer, then a polarimeter may help?

Are there any other solutes / contaminants in this MCH?

RE: Conductivity as a method for determining the solute concentration on apolar solvent: is it possible?

(OP)
The molecule have optical isomery. How a polarimeter could work, in this case? (if you have some material about functioning, uses and/or installation of these instrument i would apreciate).
About other solutes, only in small amounts. The dried up product minimum concentration is 97%, but yes, MCH has some minor contaminants.

RE: Conductivity as a method for determining the solute concentration on apolar solvent: is it possible?

Looks like you are in luck - you can find the theory on this in many chemistry textbooks - also talk to a process analyser vendor and tell them that these are optically pure isomers you are working on - polarimetric analysers are not uncommon.

RE: Conductivity as a method for determining the solute concentration on apolar solvent: is it possible?

See a book by Bard-Faulkner on electrochemical methods and look around for cyclicvoltometry and chronocoulometry. These techniques are used to determine what you are talking about.

RE: Conductivity as a method for determining the solute concentration on apolar solvent: is it possible?

(OP)
Thank you.
I will search for those references.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources