Sulfuric Acid → 2-(2-Nitro-4-trifluoromethyl-phenylazo)-6-(1-methyl-1-phenyl-ethyl)-4-(1,1,3,3-tetramethyl-butyl)-phenol

Participants

Reaction Conditions

Reaction Steps

To a 1 L lab flask are added 54.6 g (0.26 mol, 99.9%) of 4-trifluoromethyl-2-nitroaniline, PETROSUL H-60 (5.3 g dissolved in 121.4 g water), 2-cumyl-4-tert-octylphenol (80.9 g, 0.25 mol, 92.5%) and ligroine (241.7 g, bp 90-110° C.). Sulfuric acid (32.7 g, 93%) is charged to the reactor with stirring. The reaction mass is cooled to 5° C. Nitrosylsulfuric acid (94.4 g, 0.30 mol, 40% in sulfuric acid) and water (84.5 g) are added via a peristaltic pump over 8 hours. The cooling bath is removed and the reaction mass is allowed to warm to room temperature overnight. The reaction mass is heated to 40° C. Stirring is stopped and the two phases separate. Removed the aqueous layer. The ligroine layer weighed 373.8 g and contained 25.73 weight % of desired product (96.2 g of monoazo corresponding to a yield of 77% based on phenol as determined by calibrated HPLC analysis). The product may be crystallized from hot methanol, resulting in a burgundy solid with a melting point of 101-105° C. as per co-pending application Ser. No. 09/632,217 example 10. 1H-NMR (CDCl3; 499.8494 MHz): δ0.85 (s, 9H); δ1.42 (s, 6H); δ1.77 (s, 2H); δ1.78 (s, 6H); δ7.14-7.30 (multiplet, 5H); δ7.50 (d, 1H); δ7.58 (d, 1H); δ7.90 (d, 1H); δ8.15 (d, 1H); δ8.37 (s, 1H).

Provenance & Evidence