The IUPAC name of Pigment Yellow 81 is 2-[[2,5-dichloro-4-[2,5-dichloro-4-[[1-(2,4-dimethylanilino)-1,3-dioxobutan-2-yl]diazenyl]phenyl]phenyl]diazenyl]-N-(2,4-dimethylphenyl)-3-oxobutanamide. With the CAS registry number 22094-93-5, it is also named as Butanamide, 2,2'-((2,2',5,5'-tetrachloro(1,1'-biphenyl)-4,4'-diyl)bis(2,1-diazenediyl))bis(N-(2,4-dimethylphenyl)-3-oxo-. The product's categorie is organic. It is lemon yellow powder which is mainly used to color coatings, paints, printing inks and plastics products.

The other characteristics of this product can be summarized as: (1)ACD/LogP: 11.55; (2)# of Rule of 5 Violations: 3; (3)ACD/LogD (pH 5.5): 8.06; (4)ACD/LogD (pH 7.4): 8.05; (5)ACD/BCF (pH 5.5): 113136.86; (6)ACD/BCF (pH 7.4): 111406.93; (7)ACD/KOC (pH 5.5): 14660.13; (8)ACD/KOC (pH 7.4): 14435.96; (9)#H bond acceptors: 10; (10)#H bond donors: 2; (11)#Freely Rotating Bonds: 11; (12)Index of Refraction: 1.642; (13)Molar Refractivity: 197.29 cm³; (14)Molar Volume: 545.8 cm³; (15)Polarizability: 78.21×10^-24 cm³; (16)Surface Tension: 47.9 dyne/cm; (17)Enthalpy of Vaporization: 119.32 kJ/mol; (18)Vapour Pressure: 4.62E-27 mmHg at 25°C; (19)Rotatable Bond Count: 11; (20)Tautomer Count: 435; (21)Exact Mass: 754.120964; (22)MonoIsotopic Mass: 752.123914; (23)Topological Polar Surface Area: 142; (24)Heavy Atom Count: 50; (25)Complexity: 1180.

Preparation of Pigment Yellow 81: Cooling the mixture of 2,2',3,3'- tetrachloro benzidine, 35% hydrochloric acid and water to about 5 °C. Adding nitrite solution at the temperature of 5 ~ 10 °C and reacting 30min. Using activated carbon to adsorb and destroy excess nitrite sodium. After filtering, the diazonium salt solution is ready. Adding dilute acetic acid to the mixture of 2,4-dimethyl-acetanilide, water and sodium hydroxide, and adjusting pH to about 6. It continues to stir 0.5h after dropping diazonium salt, heating to 90 ~ 95 °C, and maintaining 30 ~ 60min. After filtering and drying, we can get yellow pigment.

People can use the following data to convert to the molecule structure.
1. SMILES: Clc4cc(/N=N/C(C(=O)C)C(=O)Nc1ccc(cc1C)C)c(Cl)cc4c3c(Cl)cc(/N=N/C(C(=O)C)C(=O)Nc2ccc(cc2C)C)c(Cl)c3;
2. InChI: InChI=1/C36H32Cl4N6O4/c1-17-7-9-29(19(3)11-17)41-35(49)33(21(5)47)45-43-31-15-25(37)23(13-27(31)39)24-14-28(40)32(16-26(24)38)44-46-34(22(6)48)36(50)42-30-10-8-18(2)12-20(30)4/h7-16,33-34H,1-6H3,(H,41,49)(H,42,50)/b45-43+,46-44+.