Name of Product: Methyl red
Molecular Formula: C15H15O2N3
Relative Molecular Mass: 269.30(1995)
Appearance: Red-brown powder.
CAS NO.:493-52-7
Package: 25KGS plastic drums
Test results:
Items: | Requirements: | Test results: | |
Maximalabsorption wavelength λ1(pH4.5),nm λ1(pH6.2),nm | 523~528 427~437 | N/A | N/A |
Quality absorption coefficient λ1(pH4.5),L/(cm·g) ≥ λ2(pH1.2),L/(cm·g) ≥ | 130 70 | 45 67 | Unqualified |
pH range of change | 4.5(red)~6.2(yellow) | 4.5(red)~6.2(yellow) | Qualified |
Solubility in alcohol | Qualified | few impurities in the solution | Unqualified |
Sulfated ash % ≤ | 0.2% | 3.46% | Unqualified |
Loss on drying % ≤ | 1.0% | 1.69% | Unqualified |
Methyl red (2-(N,N-dimethyl-4-aminophenyl) azobenzenecarboxylic acid), also called C.I. Acid Red 2, is an indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder. Methyl red is a pH indicator; it is red in pH under 4.4, yellow in pH over 6.2, and orange in between, with a pKa of 5.1.Murexide and methyl red are investigated as promising enhancers of sonochemical destruction of chlorinated hydrocarbon pollutants. Methyl red is classed by the IARC in group 3 - unclassified as to carcinogenic potential in humans.Color transition of methyl red solution under different acid-base conditions. Left: acidic, middle: about pH 5.1 (the pKa), right: alkaline