| abstract |
The present invention provides 3,3',5,5'-tetraisopropyl-4,4'-diphenol crystal forms I, II and III, and preparation methods thereof. Crystal form I is superior to crystal form II in terms of stability at a high temperature, high humidity, strong light and in a water medium. The preparation methods for 3,3',5,5'-tetraisopropyl-4,4'-diphenol crystal forms I, II and III provided in the invention are simple, easy to operate and suitable for technological production. |