Phosphoric Acid → Phosphate

Participants

Reaction Steps

HPLC analysis indicated substantially pure 4-(2-piperidinoethoxy)benzoic acid, hydrochloride with only minor amounts of the methyl ester. The HPLC analysis was conducted as follows: A Zorbax C8 column was used (length: 25 cm; diameter: 4.6 mm; particle size: 5 microns). A weak eluent (60 mM phosphate and 10 mM octane sulfonate) was prepared by combining 6.48 g sodium 1-octanesulfonate and 12 mL HPLC grade concentrated phosphoric acid. This mixture was diluted to 3 L with HPLC, water and the resulting solution was adjusted to pH 2 with sodium hydroxide. Acetonitrile was employed as a strong eluent. A solution of 60% weak eluent, 40% strong eluent was applied to the column at a flow rate of 1 mL/minute; detection -247 nm. Under the foregoing conditions, elution of the methyl ester occurred in five minutes; the unreacted acid eluted in 3.5 minutes.

Provenance & Evidence