Hydrogen fluoride pyridine

hydrogen fluoride ~70 %, pyridine ~30 %

Pyridinium polybifluoride, PPHF, Poly(pyridine fluoride), Pyridine hydrofluoride, Pyridinium poly(hydrogen fluoride), Olah′s reagent, HF-Pyridine
CAS Number:
Beilstein/REAXYS Number:
MDL number:
PubChem Substance ID:

Quality Level


hydrogen fluoride, ~70%
pyridine, ~30%


1.1 g/mL at 20 °C (lit.)

storage temp.


SMILES string




InChI key


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General description

May contain or form low levels of calcium fluoride during storage. Presence of this does not impact the specification values.


Convenient form of anhydrous HF, stable up to 50°C. Has been used for the preparation of β-fluoroamines from amino alcohols and for the fluorination of acetylenes.
Used together with hypervalent iodine(III) reagents for ipso-fluorination of para-substituted phenols providing cyclohexadienones. Employed with Selectfluor (Catalog No. 439479) for geminal fluorination of 2,2-diaryl-1,3-dithiolanes.
Reactant for preparation of:
  • Epimers of shikimic acid with the features of fucosylated glycans via zinc-mediated reductive ring opening followed by a Barbier reaction
  • Vaccinia H1-related (VHR) phosphatase inhibitor with a nonacidic phosphate-mimicking core structure
  • Candidates for nucleic acid drugs
  • ω-substituted gem-difluoroalkanes by oxidative desulfurization-difluorination

Reagent for:
  • Halofluorination reactions


25, 100 g in poly bottle

Legal Information

Selectfluor is a registered trademark of Merck KGaA, Darmstadt, Germany
Sure/Pac is a trademark of Sigma-Aldrich Co. LLC


CorrosionSkull and crossbones

Signal Word


Hazard Statements

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


UN 1790A2 6.1(8) / PGI

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis
Certificate of Origin
Journal of Fluorine Chemistry, 37, 343-343 (1987)
Tetrahedron, 60, 6629-6629 (2004)
V Prakash Reddy et al.
Chemical communications (Cambridge, England), (5), 654-656 (2005-01-27)
2,2-diaryl-1,3-dithiolanes, readily obtainable from diaryl ketones, were transformed into the corresponding gem-difluoro compounds using a novel reagent combination involving Selectfluor and pyridinium polyhydrogen fluoride (PPHF) under mild conditions in moderate to good yields.
Tetrahedron Letters, 32, 69-69 (1991)
Hui Shen et al.
Infection and immunity, 83(7), 2694-2704 (2015-04-22)
Fungi can shield surface pathogen-associated molecular patterns (PAMPs) for evading host immune attack. The most common and opportunistic human pathogen, Candida albicans, can shield β-(1 3)-glucan on the cell wall, one of the major PAMPs, to avoid host phagocyte Dectin-1...

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