Author Topic: A must have PTC review  (Read 1426 times)

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Nicodem

  • Guest
A must have PTC review
« on: May 04, 2004, 09:44:00 PM »
This is an old but a nice to read review on PTC catalyzed reactions. It is a good paper to get acquainted with this great method to easily perform reactions that would be otherwise very complicated and expensive.

Quarternary Ammonium Compounds in Organic Synthesis
Jozef Dockx
Synthesis (1973) 441-456.


Abstract: A survey of the use of quaternary ammonium compounds as reagents and as catalysts in homogeneous and two-phase systems is given. The use of solvents and the influence of the structure of the onium compounds on their reactivity is mentioned. A comparison with the corresponding uncatalysed systems is briefly
made.
1. Substitution Reactions
2. Elimination Reactions
3. Addition Reactions
4. Generation of Carbenes
5. Deuterium Exchange
6. Oxidation of Olefins with Potassium Permanganate
7. Sodium Borohydride Reduction
8. Influence of the Structure of the Onium Compounds
9. The Use of Ion-Exchangers as Catalysts
10. The Use of Solvents
11. Conclusion


(this is the ref. #19 in

Post 498502 (missing)

(demorol: "Alkylation of Phenols in Water w/PTC", Novel Discourse)
, ref. #1 in

Post 440729 (missing)

(Aurelius: "J.Chem.Soc.Chem.Commun 393 (1975) Ref #17", Newbee Forum)
and referenced in

Post 423224 (missing)

(Aurelius: "US Patent 4501919 (Akabori)", Stimulants)
)


Rhodium

  • Guest
Review: Practical PTC Tips
« Reply #1 on: October 01, 2004, 12:54:00 AM »
PTC in PracTiCe
Kjell Sjoberg

Aldrichimica Acta 13(3), 55-58 (1980)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/ptc.in.practice.pdf)

During the last few years articles and books on phase-transfer catalysis — PTC — have appeared in a steadily increasing stream. The stream is likely to continue increasing and will change conventional chemical syntheses and processes greatly as many areas have been touched upon only briefly. The transfer of hydrophilic ions into a lipophilic organic medium seems strange at first, but in practice the technique is remarkably simple.

For this article I have abstracted PTC information that has been valuable in our own process development work. Some ideas are taken directly from the literature while others have been developed further through our daily use.

Areas focused upon are:
  • Replacement of sodium or sodium hydride by 50% NaOH in alkylation reactions
  • Extended uses of inorganic salts in organic reactions
  • C- vs. O-alkylations
  • Transfer of "nonionic" species like H2O2 and HCl
  • Extractive separations.
I will also discuss catalyst cost and advantages of catalyst recovery. A simple quantitative analytical method for quaternary ammonium ions, the most common PTC catalysts, is described.



Related article:

Post 531883

(indole_amine: "Phase Transfer Catalysis - Comprehensive Review", Chemistry Discourse)