Bromocresol Purple

The IUPAC name of Bromocresol purple is 2-bromo-4-[3-(3-bromo-4-hydroxy-5-methylphenyl)-1,1-dioxo-2,1λ6-benzoxathiol-3-yl]-6-methylphenol. With the CAS registry number 115-40-2, it is also named as Phenol, 4,4'-(1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)bis(2-bromo-6-methyl-. The product's categories are organics; analytical chemistry; indicator (pH); pH indicators; stains and dyes. It is slightly yellow crystalline powder which is insoluble in water, soluble in ethanol, dilute sodium hydroxide and dilute sodium carbonate solution. In addition, this chemical is stable and incompatible with strong oxidizing agents. Furthermore, Bromocresol purple is used as a acid-base indicator, the color changes from pale yellow to purple-red, and the color range of pH value is 5.2-6.8. And it is also used as indicator of non-aqueous titration.

The other characteristics of this product can be summarized as: (1)ACD/LogP: 5.92; (2)# of Rule of 5 Violations: 2; (3)ACD/LogD (pH 5.5): 5.92; (4)ACD/LogD (pH 7.4): 5.78; (5)ACD/BCF (pH 5.5): 18407.13; (6)ACD/BCF (pH 7.4): 13509.09; (7)ACD/KOC (pH 5.5): 39258.75; (8)ACD/KOC (pH 7.4): 28812.21; (9)#H bond acceptors: 5; (10)#H bond donors: 2; (11)#Freely Rotating Bonds: 4; (12)Index of Refraction: 1.694; (13)Molar Refractivity: 117.07 cm³; (14)Molar Volume: 304.7 cm³; (15)Polarizability: 46.41×10^-24 cm³; (16)Surface Tension: 65.8 dyne/cm; (17)Enthalpy of Vaporization: 91.32 kJ/mol; (18)Vapour Pressure: 1.59E-14 mmHg at 25°C; (19)Rotatable Bond Count: 2; (20)Tautomer Count: 5; (21)Exact Mass: 539.906473; (22)MonoIsotopic Mass: 537.90852; (23)Topological Polar Surface Area: 92.2; (24)Heavy Atom Count: 29; (25)Complexity: 680.

Preparation of Bromocresol purple: The o-toluidine dissolved in dilute sulfuric acid, cooling, adding sodium nitrite solution under stirring, and thr reaction temperature controlled below 5 °C. When the reaction fimished, heating to 40-50 °C until no air bubbles occur, cooling and filtering, the o-cresol was obtained by fractionation and refining. Mixing o-cresol, p-toluenesulfonic acid anhydride, chloroform and zinc, stirring and heating, reacting 7h at 115-120 °C, using the steam to remove the remaining o-cresol, then the o-cresol red was obtained by filtering. After refining, o-cresol red solution was dissolved in glacial acetic acid, adding the mixture of bromine and acetic acid solution under stirring. After adding, heating 4h at 40-50 °C, cooling and filtering, then we can get the product.

When you are using this chemical, please be cautious about it as the following:
It is flammable and harmful by inhalation, in contact with skin and if swallowed. And it is also irritating to eyes, respiratory system and skin. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. If you want to contact this product, you must wear suitable protective clothing, gloves and eye/face protection.

People can use the following data to convert to the molecule structure.
1. SMILES: Brc1c(O)c(cc(c1)C3(OS(=O)(=O)c2ccccc23)c4cc(c(O)c(Br)c4)C)C;
2. InChI: InChI=1/C21H16Br2O5S/c1-11-7-13(9-16(22)19(11)24)21(14-8-12(2)20(25)17(23)10-14)15-5-3-4-6-18(15)29(26,27)28-21/h3-10,24-25H,1-2H3.