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ChemicalBook CAS DataBase List 2,5-Di-tert-butylhydroquinone

2,5-Di-tert-butylhydroquinone synthesis

9synthesis methods
-

Yield:-

Reaction Conditions:

with phosphoric acid in toluene at 70 - 105;

Steps:

1.I-1-IV Stage I:
(a) In a reactor vessel 14.25% hydroquinone and 50% toluene were added and heated at a temperature 70-100°C. (b) 10.72% tertiary butanol and 25% phosphoric acid were added to the above prepared reaction mixture of step (a) slowly within 10 to 20 hours and heated at 85-105°C. (c) The phosphoric acid layer was separated from the bottom and toluene layer was transferred to crystallizer and cooled at 30-40°C. (d) Unpurified TBHQ was precipitated and transferred to a nutch filter for further purification. Stage II: (e) Above prepared TBHQ from stage (I) and mixed with acetone and water mixture (0.70 to 1.30 times of weight of collected TBHQ) into the reactor vessel and heated at the temperature 75-95°C. (f) Above prepared solution was filtered out and cooled at 20-40°C in the crystallizer. (g) From the above prepared solution 2, 5-di TBHQ was separated as filtrate and remaining TBHQ was further crystallized out with acetone and water distilled out at 110°C. (h) TBHQ was transferred for further purification to stage III. Stage III: (i) Above collected TBHQ was reacted with isopropyl benzene (3 to 5 times of weight of collected TBHQ) in the reactor vessel and heated at 100- 125°C. (j) The above prepared solution was filtered out and cooled at 15-25°C in the crystallizer. (k) Pure TBHQ was reprecipitated and transferred to the nutch filter for drying. Stage IV: (l) The above prepared TBHQ from stage III was added to a dryer and heated upto 80°C under vacuum of 700-760 mm. (m) Dried TBHQ was collected as a finished product.

References:

MILESTONE PRESERVATIVES PVT. LTD.;SHAH, Rajiv Ashokbhai;VORA, Rasiklal Amulakhbhai WO2020/136678, 2020, A1 Location in patent:Page/Page column 9; 10; 11

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