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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: sotirone on June 02, 2021, 12:34:38 PM

Title: Where is the Hydrochloric Acid in an Organic Hydrochloric salt?
Post by: sotirone on June 02, 2021, 12:34:38 PM

Hello, pharmaceutics student here, I have a professor that asks weird questions like this and I cannot find any answers to them in my textbooks.

We are meant to explain what e.g. the HCl molecule binds to and how, for example in Chlorodiazepoxide Hydrochloride or Cocaine Hydrochloride. I suppose she means in solid form, since in solution the salt will dissociate.

Any ideas what would be an acceptable answer to this question?

Title: Re: Where is the Hydrochloric Acid in an Organic Hydrochloric salt?
Post by: Orcio_87 on June 02, 2021, 01:13:12 PM

As of chlorodiazepoxide H⁺ will probably bind to oxygen atom, as it is negative charged.

As of cocaine H⁺ will bind to nitrogen atom.

As of solid form - they should form crystals like [chlorodiazepoxide-H⁺][Cl^-] (http://scripts.iucr.org/cgi-bin/paper?a03912)

Title: Re: Where is the Hydrochloric Acid in an Organic Hydrochloric salt?
Post by: Babcock_Hall on June 02, 2021, 02:46:08 PM

@OP,

You should look for the most basic site in the molecule.  You can judge this in general on the basis of pK_a values of functional groups.  If particular pK_a values for a compound are known, then this would be even better.

Title: Re: Where is the Hydrochloric Acid in an Organic Hydrochloric salt?
Post by: sotirone on June 05, 2021, 06:23:22 AM

Great! Thank you both!