I already used CH3COOH but there still chalcone in my product that I cannot separated from pyrazoline. I tried column chromatography and also preparative tlc but still more than one spot in my product. It also contained 4 spots before purification. The one spot was chalcone, green colored under uv 366 nm, the other was pyrazoline that blue colored under uv 366 nm but not very strong fluorescence, and 2 others I don't know and it was not my starting materials I used and do not fluorescence under uv 366 nm. I used vanillin and 4-chloroacetophenone to synthesize chalcone.