Methyl red chloride (493-52-7)

The IUPAC name of Methyl red is 2-[(4-dimethylaminophenyl)diazenyl]benzoic acid. With the CAS registry number 493-52-7, it is also named as Benzoic acid, o-((p-(dimethylamino)phenyl)azo)-. The product's categories are organics; analytical chemistry; indicator (pH); biochemical reagents for identification; microbiology; indicator solutions; indicators; stains and dyes; titration. It is dark red crystalline powder which is soluble in ethanol, acetic acid, and almost insoluble in water. In addition, Methyl red is stable and incompatible with strong oxidizing agents.  

The other characteristics of this product can be summarized as: (1)ACD/LogP: 4.91; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 3.15; (4)ACD/LogD (pH 7.4): 1.88; (5)ACD/BCF (pH 5.5): 54.64; (6)ACD/BCF (pH 7.4): 2.93; (7)ACD/KOC (pH 5.5): 192.16; (8)ACD/KOC (pH 7.4): 10.3; (9)#H bond acceptors: 5; (10)#Freely Rotating Bonds: 4; (11)Index of Refraction: 1.592; (12)Molar Refractivity: 77.97 cm³; (13)Molar Volume: 230.1 cm³; (14)Polarizability: 30.91×10^-24 cm³; (15)Surface Tension: 44.3 dyne/cm; (16)Enthalpy of Vaporization: 78.36 kJ/mol; (17)Vapour Pressure: 5.27E-10 mmHg at 25°C; (18)Rotatable Bond Count: 4; (19)Exact Mass: 269.116427; (20)MonoIsotopic Mass: 269.116427; (21)Topological Polar Surface Area: 65.3; (22)Heavy Atom Count: 20. 

Preparation of Methyl red: It is obtained by diazotization of anthranilic acid, followed by reaction with dimethylaniline:

Uses of Methyl red: is one of acid-base indicator used for identification, such as: indicator solutions. It is red in pH under 4.4, yellow in pH over 6.2, and orange in between, with a pKa of 5.1. And it is also used for staining protozoa in vivo.

When you are using this chemical, please be cautious about it as the following:
It is highly flammable, so it should be kept away from sources of ignition. And it is harmful by inhalation, in contact with skin and if swallowed. In addition, Methyl red is irritating to eyes, respiratory system and skin, so people must not breathe dust and avoid contact with skin and eyes. In case of contact with eyes, rinse aimmediately 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. In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) Take precautionary measures against static discharges.

People can use the following data to convert to the molecule structure. 
1. SMILES: O=C(O)c2ccccc2/N=N/c1ccc(N(C)C)cc1;
2. InChI: InChI=1/C15H15N3O2/c1-18(2)12-9-7-11(8-10-12)16-17-14-6-4-3-5-13(14)15(19)20/h3-10H,1-2H3,(H,19,20)/b17-16+.

IARC Cancer Review: Group 3 IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 , 1987,p. 56.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 8 , 1975,p. 161.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . Reported in EPA TSCA Inventory. EPA Genetic Toxicology Program.