Methyl Red CAS 493-52-7
Introduction：Basic information about Methyl Red CAS 493-52-7, including its chemical name, molecular formula, synonyms, physicochemical properties, and safety information, etc.
Methyl Red Basic informationDescription
| Product Name: | Methyl Red |
| Synonyms: | CI NO 13020;BROMOCRESOL GREEN-METHYL RED;BROMOCRESOL GREEN-METHYL RED ETHANOL;BROMOCRESOL GREEN/METHYL RED, MIXED INDICATOR;BROMOCRESOL GREEN/METHYL RED, MIX INDICATOR FOR ALKALINITY;2-(4-Dimethylaminophenylazo)benzoic acid, 4-Dimethylaminoazobenzene-2μ-carboxylic acid, Acid Red2;METHYL RED;METHYL RED INDICATOR |
| CAS: | 493-52-7 |
| MF: | C15H15N3O2 |
| MW: | 269.3 |
| EINECS: | 207-776-1 |
| Product Categories: | BTitration;Indicator Solutions;Indicators;Stains and Dyes;Stains&Dyes, A to;Titration;Biochemical Reagents for Identification;Identification Tests&Reagents;Microbiology;Analytical Chemistry;Indicator (pH);pH Indicators;Organics;Azo |
| Mol File: | 493-52-7.mol |
Methyl Red Chemical Properties
| Melting point | 179-182 °C (lit.) |
| Boiling point | 412.44°C (rough estimate) |
| bulk density | 300-500kg/m3 |
| density | 0.839 g/mL at 25 °C |
| vapor density | 9.3 (vs air) |
| refractive index | 1.5930 (estimate) |
| Fp | 11 °C |
| storage temp. | Store at +5°C to +30°C. |
| solubility | ethanol: soluble1mg/mL |
| pka | 4.95(at 25℃) |
| form | Solid |
| Colour Index | 13020 |
| color | Reddish-violet |
| Odor | Odorless |
| PH Range | 4.4(red)-6.3(yellow) |
| Water Solubility | Practically insoluble in water. Soluble in alcohol, acetic acidSoluble in ethanol. Insoluble in water. |
| ε(extinction coefficient) | ≥10000 at 282-288nm in methanol ≥20000 at 509-519nm in methanol ≥7000 at 329-335nm in methanol |
| λmax | 410nm, 530nm, 427nm, 519nm |
| Merck | 14,6119 |
| BRN | 750102 |
| Stability: | Stable. Incompatible with strong oxidizing agents. |
| Major Application | Waveguides, LED sensors, photoresists, liquid crystals, sol-gel matrix, optical sensors, paints, toys, detection of thiols, food freshness sensors, dental product, saliva sampling method, detecting lactic acid, carbohydrates |
| InChI | 1S/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) |
| InChIKey | CEQFOVLGLXCDCX-MSUUIHNZSA-N |
| SMILES | N(C)(C)c1ccc(cc1)N=Nc2c(cccc2)C(=O)O |
| CAS DataBase Reference | 493-52-7 |
| IARC | 3 (Vol. 8, Sup 7) 1987 |
| NIST Chemistry Reference | Benzoic acid, 2-[[4-(dimethylamino)phenyl]azo]-(493-52-7) |
| EPA Substance Registry System | Methyl red (493-52-7) |
Safety Information
| Hazard Codes | Xn,T,F,Xi,C,N |
| Risk Statements | 10-20/21/22-68/20/21/22-68-36/38-23/25-11-36/37/38-34-51/53-39/23/24/25-23/24/25 |
| Safety Statements | 36/37-24/25-22-45-33-24-16-7-36-26-36/37/39-61 |
| RIDADR | UN 1170 3/PG 2 |
| WGK Germany | 1 |
| RTECS | DG8960000 |
| TSCA | TSCA listed |
| HazardClass | 3 |
| PackingGroup | II |
| HS Code | 29270000 |
| Storage Class | 11 - Combustible Solids |
| Hazardous Substances Data | 493-52-7(Hazardous Substances Data) |
| Description | Methyl red is a commonly used indicator for acid-base titrations. This chemical is usually yellow but turns red below pH 4.0. Bacteria exhibiting mixed acids fermentation will accumulate acids in the medium, resulting in a color change. Approximately five drops of methyl red reagent are added to an overnight culture grown in MRVP broth to determine the test result. Different bacteria convert dextrose and glucose to pyruvate using different metabolic pathways. Some of these pathways produce unstable acidic products which quickly convert to neutral compounds. Some organisms use the butylene glycol pathway, which produces neutral end products, including acetoin and 2,3-butanediol. Other organisms use the mixed acid pathway, which produces acidic end products such as lactic, acetic, and formic acid. These acidic end products are stable and will remain acidic. The Methyl Red test involves adding the pH indicator methyl red to an inoculated tube of MR-VP broth. If the organism uses the mixed acid fermentation pathway and produces stable acidic end-products, the acids will overcome the buffers in the medium and produce an acidic environment in the medium. When methyl red is added, if acidic end products are present, the methyl red will stay red. |
| Chemical Properties | dark red crystalline powder |
| Uses | Used as pH indicator. |
| Uses | As indicator in 0.1% alcoholic solution; pH: 4.4 red, 6.2 yellow. Used for titrating NH3, weak organic bases, e.g., alkaloids; not suitable for organic acids, except oxalic and picric acid. Methyl red is easily reduced, thereby losing its color, and readings should be made promptly. It is gradually being replaced by sulfonphthalein indicators, such as bromcresol green, which are more stable and exhibit a sharper change in color. |
| Uses | pH indicator in pH range 4.2 - 6.3Methyl red is used as a pH indicator. It is red in pH less than 4.4 and yellow in pH over 6.2. It is used to study its degradation using Fenton's reagent. In microbiology, it is used to identify bacteria producing stable acids by mechanisms of mixed acid fermentation of glucose. |
| Definition | ChEBI: An azo dye consisting of benzoic acid substituted at position 2 by a 4-[(dimethylamino)phenyl]diazenyl group. |
| Definition | An acid–base indicator that isred in solutions below a pH of 4.2 and yellowabove a pH of 6.3. It is often used forthe same types of titration as methyl orangebut the transition range of methyl redis nearer neutral (pH7) than that of methylorange. The two molecules are structurallysimilar. |
| Definition | methyl red: An organic dye similarin structure and use to methyl orange.It changes from red below pH4.4 to yellow above pH 6.0 (at 25°C). |
| Preparation | 2-Aminobenzoic acid?diazo, and N,N-dimethylaniline coupling. |
| General Description | Methyl red solution is an azo dye which turns to red when pH is below 4.4 (yellow pH < 6.2, orange pH 4.4-6.2). Some bacteria utilize glucose to form large amounts of acid with the result that the pH value of the medium falls distinct. Other species produce no or less free acid. This difference can be visualized by using methyl red. This test is used to differentiate enteric bacteria. |
| Hazard | Questionable carcinogen. |
| Biochem/physiol Actions | Methyl Red is a maroon red crystal azo dye. Methyl Red is a pH indicator and changes color at a pH of 5.5. Methyl Red is widely used in saliva sampling method. In addition, it is also employed in carbohydrate and lactic acid detection. Methyl Red has been effectively used for intrageneric differentiation of Enterobacteriaceae. |
| Safety Profile | Questionable carcinogen with experimental tumorigenic data. Mutation data reported. When heated to decomposition it emits toxic fumes of NOx. |
| Properties and Applications | moderate soluble in ethanol, insoluble in water. Alcohol solution to join hydrochloric acid for purple; Add sodium hydroxide to dim yellow. |
| Purification Methods | The acid is extracted with boiling toluene using a Soxhlet apparatus. The crystals which separate on slow cooling to room temperature are filtered off, washed with a little toluene and recrystallised from glacial acetic acid, *benzene or toluene followed by pyridine/water. Alternatively, dissolve it in aqueous 5% NaHCO3 solution, and precipitate it from a hot solution by dropwise addition of aqueous HCl. Repeat this until the extinction coefficients do not increase. [Beilstein 16 IV 504.] |
Methyl Red Preparation Products And Raw materials
| Raw materials | N,N-Dimethylaniline-->Anthranilic acid-->N,N-Dimethylaniline-->Anthranilic acid |
| Preparation Products | Triethyl phosphite-->Calcium phosphate dibasic dihydrate-->Calcium phosphate dibasic-->Aceglutamide |
