4-Hydroxybenzoic Acid → Benzoic acid, 4-(benzoyloxy)-

Temperature

2.5 °C

138.1 g (1.0 mol) of para-hydroxybenzoic acid were first dissolved in 400 ml of water and 600 ml of isopropanol and this solution was admixed at 0 to 5° C. with 235.7 g of KOH solution (50% strength by weight aqueous solution, 2.1 mol). The resulting pH was 14. Metered into this solution over the course of one hour, then, at 0 to 5° C., were 140.4 g (1.0 mol) of benzoyl chloride, and the batch was stirred for 30 minutes at 0 to 5° C. thereafter. At the end of the after-stirring, the pH of the reaction mixture was 9.3. The reaction mixture was subsequently adjusted to a pH of 8 at 0 to 5° C. using 25.0 g of HCl solution (32% strength by weight aqueous solution), and the complete solution was heated to 55 to 60° C. and then adjusted to a pH of 1.5 to 3 using 100 g of HCl solution (32% strength by weight aqueous solution). The reaction mixture was cooled to 20 to 25° C. and the solid was filtered off on a suction filter and washed ten times with 150 ml of water. The yield after drying under reduced pressure at 100° C. was 220.5 g (91.0% of theory). According to HPLC and NMR measurement, the product was free from benzoic acid and from unreacted para-hydroxybenzoic acid. The purity of the product is >99.9% by weight.

1. customover the course of one hour
2. customat 0 to 5° C.
3. customwas subsequently adjusted to a pH of 8 at 0 to 5° C.
4. temperaturethe complete solution was heated to 55 to 60° C.
5. temperatureThe reaction mixture was cooled to 20 to 25° C.
6. filtrationthe solid was filtered off on a suction
7. filtrationfilter
8. washwashed ten times with 150 ml of water
9. customThe yield
10. customafter drying under reduced pressure at 100° C.

ORD record

ord-2d876711e8e143bfb2d10dcb3bc7b37d

Source dataset

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08907118B2