Description
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;
| Description | |
|---|---|
| Catalogue Number | ZA.002.746 |
| Synonyms | 4-Dimethylaminoazobenzene-2′-carboxylic acid |
| Product Information | |
|---|---|
| CAS number | 493-52-7 |
| EC number | 207-776-1 |
| Grade | ACS,Reag. Ph Eur |
| Hill Formula | C₁₅H₁₅N₃O₂ |
| Molar Mass | 269.31 g/mol |
| HS Code | 2927 00 00 |
| Structure formula Image | |
| Quality Level | MQ200 |
| Physicochemical Information | |
|---|---|
| Melting Point | 178 – 182 °C |
| Bulk density | 300 – 500 kg/m3 |
| Safety Information according to GHS | |
|---|---|
| Storage class | 10 – 13 Other liquids and solids |
| WGK | WGK 2 obviously hazardous to water |
| Disposal | 3 Relatively unreactive organic reagents should be collected in container A. If halogenated, they should be collected in container B. For solid residues use container C. |
| Safety Information | |
|---|---|
| Hazard Symbols |  Dangerous for the environment |
| Categories of danger | dangerous for the environment |
| R Phrase | R 51/53 Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. |
| S Phrase | S 61 Avoid release to the environment. Refer to special instructions/ Safety data sheets. |
| Storage and Shipping Information | |
|---|---|
| Storage | Store at +5°C to +30°C. |
| Transport Information | |
|---|---|
| Declaration (railroad and road) ADR, RID | Kein Gefahrgut |
| Declaration (transport by air) IATA-DGR | No Dangerous Good |
| Declaration (transport by sea) IMDG-Code | No Dangerous Good |
| Specifications | |
|---|---|
| Identity (UV/VIS-Spectrum) | passes test |
| Appearance | Red to red-violet powder, eventually with granular parts. |
| Clarity of solution (1 g/l; ethanol) | passes test |
| Melting point (capillary method, temperatur measerment in the heating block) | 179 – 182 °C |
| Transition range | pH 4.4 – pH 6.0 Red – yellow |
| Absorption maximum (buffer pH 4.5) | 523 – 526 nm |
| Absorption maximum (buffer pH 6.2) | 427 – 437 nm |
| Spec. Absorptivity A 1%/1cm (λmax; 0.005 g/l; buffer pH 4.5; calculated on anhydrous substance) | 1350 – 1500 |
| Spec. Absorptivity A 1%/1cm (λmax; 0.005 g/l; buffer pH 6.2; calculated on anhydrous substance) | 700 – 800 |
| Transition range (according to ACS) | passes test |
| Loss on drying (110 °C) | ≤ 5 % |
![Universal indicator solution uniLAB, Merck [100ml]](https://idealmedical.co.za/wp/wp-content/uploads/2020/08/276-pH-indicator-soln-300x300.jpg)
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