反应详情

0.05 moles of 2,5-dichloro-3-nitro-terephthalic acid were refluxed in 2.11 moles of dimethyl sulphoxide (DMSO) at 189° C. for 70 minutes, after which the DMSO was removed by flash evaporation. The residue was dissolved in saturated sodium bicarbonate solution, which was extracted with chloroform to remove unwanted side-products. The aqueous phase was then acidified with 10% hydrochloric acid to complete precipitation and the resulting precipitate was filtered off, washed well with water and dried to give 88.5% crude yield of 2,5-dichloro-3-nitro-benzoic acid, melting at 214°-216° C.

1. customafter which the DMSO was removed by flash evaporation
2. dissolutionThe residue was dissolved in saturated sodium bicarbonate solution
3. extractionwhich was extracted with chloroform
4. customto remove unwanted side-products
5. customprecipitation
6. filtrationthe resulting precipitate was filtered off
7. washwashed well with water
8. customdried