1) add 3 wt. parts of phosphoric acid and 0.1 wt. parts of water into a stirring cylinder, followed by adding 6 wt. parts of hydroquinone, and start the stirrer for mixing; 2) transfer the mixed solution into a reactor, and add tertiary butanol slowly after heating up to 59°C; 3) continue to heat up to 81°C, and maintain the reaction at this temperature for 2 hrs; 4) after completion of the reaction, centrifuge the product, and then wash and dehydrate it to obtain TBHQ crude oil; 5) mix 1 wt. part of acid with 95 wt. part of water, heat to 81°C, then add 6.5 wt. part of TBHQ crude oil, and heat to 95°C with stirring; 6) carry out a first centrifugation of the solution of step 5) to isolate DTBHQ insoluble in water, and then subsequently cool down the solution to below 45°C, carry out a second centrifugation, and the TBHQ crystals obtained are washed, dehydration and then dried; during the drying process, the wet TBHQ crystals were uniformly spread on a vibrating screen, sieved and then flatly spread on a drying disk with the thickness controlled at 5 cm, and dried for 8 hours, and ultimately obtained a TBHQ boutique product with a TBHQ content of 99.9% and a DTBHQ content of 0.1%.
