Description
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Methyl Red

Description
Product Name
Methyl Red
CAS No.
493-52-7
Chemical Name
Methyl Red
Synonyms
ACID RED;METHYL RED INDICATOR;METHYL RED MIXED SOLUTION;METHYL RED, SPIRIT SOLUBLE;METHYL RED ETHANOL;METHYL RED SOLUTION R;METHYL RED, WATER SOLUBLE;METHYL RED MIXED SOLUTION R;O-(P-DIMETHYLAMINOPHENYLAZO)BENZOIC ACID;ACID RED 2
CBNumber
CB1112962
Molecular Formula
C15H15N3O2
Formula Weight
269.3
MOL File
493-52-7.mol
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Methyl Red Property

Melting point:
179-182 °C (lit.)
Boiling point:
412.44°C (rough estimate)
Density 
0.839 g/mL at 25 °C
vapor density 
9.3 (vs air)
refractive index 
1.5930 (estimate)
Flash point:
11 °C
storage temp. 
Store at +5°C to +30°C.
solubility 
ethanol: soluble1mg/mL
form 
Solid
pka
4.95(at 25℃)
Colour Index 
13020
color 
Reddish-violet
PH Range
4.4(red)-6.3(yellow)
Odor
Odorless
Water Solubility 
Practically insoluble in water. Soluble in alcohol, acetic acidSoluble in ethanol. Insoluble in water.
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
InChIKey
CEQFOVLGLXCDCX-MSUUIHNZSA-N
CAS DataBase Reference
493-52-7
NIST Chemistry Reference
Benzoic acid, 2-[[4-(dimethylamino)phenyl]azo]-(493-52-7)
IARC
3 (Vol. 8, Sup 7) 1987
EPA Substance Registry System
Methyl red (493-52-7)
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Safety

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 
Yes
HazardClass 
3
PackingGroup 
II
HS Code 
29270000
Hazardous Substances Data
493-52-7(Hazardous Substances Data)
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Hazard and Precautionary Statements (GHS)

Symbol(GHS)
Signal word
Danger
Hazard statements

H225Highly Flammable liquid and vapour

H319Causes serious eye irritation

H371May cause damage to organs

Precautionary statements

P210Keep away from heat/sparks/open flames/hot surfaces. — No smoking.

P260Do not breathe dust/fume/gas/mist/vapours/spray.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P337+P313IF eye irritation persists: Get medical advice/attention.

P403+P235Store in a well-ventilated place. Keep cool.

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N-Bromosuccinimide Price

Sigma-Aldrich
Product number
250198
Product name
Methyl Red
Purity
ACS reagent, crystalline
Packaging
25g
Price
$117
Updated
2024/03/01
Sigma-Aldrich
Product number
318728
Product name
Bromocresol Green/Methyl Red, mixed indicator solution
Purity
in methanol
Packaging
500ML
Price
$132
Updated
2024/03/01
Sigma-Aldrich
Product number
1.06076
Product name
Methyl red (C.I. 13020)
Purity
indicator ACS,Reag. Ph Eur
Packaging
25g
Price
$57.1
Updated
2024/03/01
Sigma-Aldrich
Product number
1.06076
Product name
Methyl red (C.I. 13020)
Purity
indicator ACS,Reag. Ph Eur
Packaging
100g
Price
$200
Updated
2024/03/01
Sigma-Aldrich
Product number
08714
Product name
Methyl Red solution
Purity
suitable for microbiology
Packaging
100mL
Price
$36.4
Updated
2022/05/15
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Methyl Red Chemical Properties,Usage,Production

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 is red in solutions below a pH of 4.2 and yellow above a pH of 6.3. It is often used for the same types of titration as methyl orange but the transition range of methyl red is nearer neutral (pH7) than that of methyl orange. The two molecules are structurally similar.

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

Preparation Products

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Methyl Red Suppliers

Shenyang Xianchuang Chemical Co., Ltd.
Tel
024-23769576 13840269002
Fax
024-23769576
Email
274311108@qq.com
Country
China
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SHENYANG SINOCHEM BIOTECH CO.,LTD
Tel
024-23769576 13840269002
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274311108@qq.com
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China
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Shenyang yimoke chemical products co. LTD
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13998106873
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297303255@qq.com
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China
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J & K SCIENTIFIC LTD.
Tel
010-82848833 400-666-7788
Fax
86-10-82849933
Email
jkinfo@jkchemical.com
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China
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96815
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Meryer (Shanghai) Chemical Technology Co., Ltd.
Tel
021-61259108 18621169109
Fax
86-21-61259102
Email
market03@meryer.com
Country
China
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40228
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Alfa Aesar
Tel
400-6106006
Fax
021-67582001/03/05
Email
saleschina@alfa-asia.com
Country
China
ProdList
30123
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TCI (Shanghai) Development Co., Ltd.
Tel
021-67121386
Fax
021-67121385
Email
Sales-CN@TCIchemicals.com
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China
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Beijing HwrkChemical Technology Co., Ltd
Tel
010-89508211 18501085097
Fax
010-89508210
Email
sales.bj@hwrkchemical.com
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China
ProdList
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JinYan Chemicals(ShangHai) Co.,Ltd.
Tel
13817811078
Fax
86-021-50426522,50426273
Email
sales@jingyan-chemical.com
Country
China
ProdList
9976
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Shanghai Hanhong Scientific Co.,Ltd.
Tel
021-54306202 13764082696
Email
info@hanhongsci.com
Country
China
ProdList
42958
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View Lastest Price from Methyl Red manufacturers

Hebei Zhuanglai Chemical Trading Co.,Ltd
Product
Methyl Red 493-52-7
Price
US $10.00/kg
Min. Order
1kg
Purity
99%
Supply Ability
20ton
Release date
2024-05-24
Hebei Weibang Biotechnology Co., Ltd
Product
Methyl Red 493-52-7
Price
US $100.00/kg
Min. Order
1kg
Purity
99%min
Supply Ability
200TON
Release date
2024-10-28
Hebei Weibang Biotechnology Co., Ltd
Product
Methyl Red 493-52-7
Price
US $0.00/KG
Min. Order
1KG
Purity
99%
Supply Ability
500000kg
Release date
2024-10-25

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