Melting point: 290℃
Boiling point: 479.59℃ (rough estimate)
Density: 0.998 g/cm3
Refractive index: 1.5300 (estimate)
The crystal with green luster is reddish brown powder after grinding. Soluble in alcohol and dilute sodium hydroxide solution, slightly soluble in water.
Acid base reminder. Prepare 0.1% solution or 0.04% aqueous solution with 20% ethanol (take 0.04g of the product and dissolve it in 1.05ml of 0.1mnaoh solution), and then dilute it to 100ml. PH discoloration range: 7.2 (yellow) - 8.8 (purple); 2.0 (red) - 3.0 (Amber).
Mix benzenesulphonic anhydride, o-cresol and anhydrous zinc chloride, stir and heat, condense at 115-120 ℃ for about 7h, and purge the remaining o-cresol with steam. Filter, dissolve the filter cake with hot sodium carbonate aqueous solution, filter, neutralize with 1:1 hydrochloric acid in the clear filtrate, and stir vigorously. The crystals were filtered out, washed with a small amount of water and dried to obtain the finished product. If necessary, it can be purified by recrystallization of glacial acetic acid.