Abstract
Sulfonephthaleins can be synthesized in a single pot from saccharin and phenol via the in situ formation of 2-sulfobenzoic anhydride, followed by its reaction with phenol using H2SO4 as the condensing agent, in the absence of any solvent. This solvent-free synthesis is more economical and environmentally benign.
GRAPHICAL ABSTRACT
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Keywords:
ACKNOWLEDGMENT
V. R. C. and D. K. D. are grateful to the National Academy of Sciences, India, for the Senior Scientist Platinum Jubilee Fellowship and Project Assistantship, respectively.
Notes
a Yields indicated here are isolated yields. Phenol red is water soluble and could not be fully recovered after workup.
a BF3 etherate, Dowex-50, Amberlyst-15, HCl, Hβ zeolite, HY zeolite, or ZnCl2.