1
$\begingroup$

I am planning to synthesize thymolphthalein, a pH indicator. I am wondering if phosphoric acid can be used to substitute sulfuric acid in the preparation. I know it can catalyze Friedel-Crafts reactions, which are a part of the synthesis. Any advice would be appreciated.

Thymolphthalein synthesis

$\endgroup$
9
  • $\begingroup$ It would be appreciated if you could attach an image of the normal synthesis involving sulphuric acid. Would help those who are not aware of the compound. Thank you :) $\endgroup$
    – TRC
    Jul 25 at 14:44
  • 1
    $\begingroup$ If you use polyphosphoric acid (PPA) I think it will work. PTSA will also probably work $\endgroup$
    – Waylander
    Jul 25 at 15:05
  • 2
    $\begingroup$ What is your reasoning for, what is your reasoning against the substitution of the strong Bronsted acid $\ce{H2SO4}$ by phosphoric acid (i.e., review of the literature)? By the way, the waxy polyphosphoric acid may be considered, too (an elder review, a current application). $\endgroup$
    – Buttonwood
    Jul 25 at 15:06
  • $\begingroup$ I do chemistry in a workspace with wooden benches, and sulfuric acid would eat through them quickly. Thanks for suggesting those, I can make or get both of those. $\endgroup$
    – Jacob
    Jul 25 at 15:19
  • $\begingroup$ But the question is: would straight phsophoric acid work? $\endgroup$
    – Jacob
    Jul 25 at 16:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.