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Methyl Red CAS 493-52-7

Molecular Formula: C15H15N3O2

Formula Weight: 269.3

ZSpharmac: Methyl Red Supplement

Product Name: Methyl Red
CAS No: 493-52-7
Purity: 99%

Basic Info

Product Name:Methyl Red
Other Names:Methyl Red, Indicator
Place of Origin:Shandong, China
Brand Name:ZSpharmac
Type:Organic Chemical Raw Materials
Appearance:Crystalline Solid
EINECS No.:262-390-0
Storage:Reddish-violet Solid
Provide:Methyl Red MSDS;
Methyl Red COA

What is Methyl Red?

The molecular formula of methyl red is C15H15N3O2. Molecular weight 269.31. Luminous purple crystals were obtained from toluene. Melting point 183°C, pKa1=2.5, pKa2=9.5, pKb=4.8. Soluble in ethanol, acetone, benzene, chloroform, acetic acid, almost insoluble in water. Preparation method: derived from the coupling of the diazotized product of anthranilic acid and dimethylaniline. Uses: It can be used as an acid-base indicator when it is made into 0.1% ethanol solution. It is red when pH 4.4 and yellow when pH 6.2. It is widely used in the titration of strong acid and weak base, because it is easy to be oxidized and faded, so the reading must be read immediately when the end point of the titration is reached.

The existing method of synthesizing methyl red, some use ethanol as the reaction medium, the cost is high, the product is difficult to filter, and the yield is low, and some use water as the reaction medium, although the yield (66%) is improved, but still There are the following problems: the acid-base consumption is large, and during the diazotization of anthranilic acid, add the hydrochloric acid that is equivalent to more than twice the amount of anthranilic acid molar weight, so that in the coupling reaction step, a large amount of alkali needs to be added and excess acid is combined. In the coupling reaction, the amount and rate of addition of alkali directly affect the yield and quality. The generated methyl red is an amorphous precipitate, which is viscous and difficult to filter and difficult to wash. , The purity of the crude product is not high, and it is generally purified by recrystallization from an organic solvent.

Methyl Red Properties:

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)
Fp 11 °C
storage temp. Store at +5°C to +30°C.
solubility ethanol: soluble1mg/mL
Colour Index 13020
form Solid
pka4.95(at 25℃)
color Reddish-violet
PH Range4.4(red)-6.3(yellow)
Water Solubility Practically insoluble in water. Soluble in alcohol, acetic acidSoluble in ethanol. Insoluble in water.


Methyl Red Uses

  1. Methyl Red is one of the generally made use of acid-base indicators, the common concentration is 0.1% ethanol solution, pH4.4 (red)-6.2 (yellow). Additionally utilized for in vivo discoloration of protozoa.
  2. Methyl Red is a protozoan living dye; acid-base indicator, pH discoloration range from 4.4 (red) to 6.2 (yellow); titration of ammonia, weak natural bases and alkaloids, but not appropriate for natural acids apart from oxalic acid as well as picric acid; Can be combined with bromocresol eco-friendly and methylene blue to create a blended indication to reduce the color change variety as well as boost the level of sensitivity of shade adjustment; adsorption sign for rainfall titration.
  3. Methyl Red is used for clinical serum protein biochemical tests.

Other Applications of Methyl Red

1. It is utilized to promptly evaluate the acidity and also alkalinity of tetrafluoroethylene gas.
Initially, prepare bromothymol blue methyl red mixed indicator, consider 0.1 g of bromothymol blue, dissolve it in 8.0 mL of salt hydroxide solution with a concentration of 0.02 mol/L, and also dilute to 250 mL. Evaluate 0.1 g of methyl red, dissolve it in 3.73 mL of sodium hydroxide solution with a concentration of 0.02 mol/L, and also thin down to 250 mL. Mix the two solutions to make bromothymol blue methyl red combined sign. Take a 250mL glass conical flask, include 25mL pure water, and include 2 decreases of bromothymol blue methyl red combined indication. At the outlet of the valve of the sampling port gauged by the tool, link an area of latex tube, pass the latex tube into the service in the cone-shaped flask, open up the gas shutoff, and come on tetrafluoroethylene gas at a price of 500ml per min for 2 mins, till the shade of the service is stable., the level of acidity and alkalinity of tetrafluoroethylene gas can be identified. The technique of the development is simple and also hassle-free, as well as the driver can swiftly accomplish the level of acidity evaluation of the tetrafluoroethylene gas right away. 2. For evaluating totally free amine material in NMP.
The method consists of the adhering to actions: preparing a bromocresol green-methyl red indicator; taking a specific amount of NMP example in a container, adding isopropanol and drinking it efficiently to blend it; including the bromocresol green-methyl red indicator Mix evenly, titrate with standard hydrochloric acid service, as well as end the titration from environment-friendly to somewhat yellow; according to the formula: % complimentary amine=c * V common * K/ ρ * V, calculate the % totally free amine in the NMP example. In today invention, the bromocresol green-methyl red sign is prepared, as well as the approach of acid-base titration is utilized to examine the material of amine in NMP. According to the parameters in the acid-base titration procedure, the totally free amine material is shared in mass portion: c * V is marked with * K/ ρ * V, as well as the efficiency of NMP is assessed according to the examination results. On top of that, the examination method is easy, practical, rapid and low in cost, and can be extensively used in manufacturing and also research.

3. For the preparation of a CO2 sensitive indicator label.
First prepare 10%~90% ethanol solution; 0.07~0.12g methyl red is dissolved in 100mL ethanol solution to obtain methyl red ethanol solution; 0.08~0.15g bromothymol blue is dissolved in 100mL ethanol solution to obtain bromine Thymol blue ethanol solution; mix 10~55mL methyl red ethanol solution with 15~50mL bromothymol blue ethanol solution, dilute 10 times to obtain indicator solution; add glycerin, heat in a constant temperature water bath, and put it in when it reaches the rated temperature 1.2~2.2g methyl cellulose, stir continuously at high speed to form a uniform methyl cellulose solution; as the temperature drops, the viscosity of the solution increases; obtain the indicator film liquid; scrape the indicator film liquid on the cotton fiber paper , under blast drying to obtain CO2-sensitive indicator labels. This instruction label is suitable for rapid detection of CO2 content in the environment between 0 and 100%.

Degradation Method of Methyl Red

A kind of degradation method of methyl red, described degradation method steps are as follows:

Step 1. Preparation of modified bovine serum albumin: Dissolve bovine serum albumin in deionized water, add acid anhydride, and stir the reaction at room temperature. After the reaction is complete, a mixed solution A is formed, and the mixed solution A is transferred into the dialysis bag , and conduct dialysis with deionized water to remove excess acid anhydride; after the dialysis, transfer the mixture A in the dialysis bag into a beaker, then add the o-phenanthroline complex, stir the reaction at room temperature, and then add the mixture after the reaction is completed. Move into the dialysis bag, and use the EDTANa solution of 1.0-6.0mmol/L to carry out dialysis, remove excessive EDTANa , the mixed solution B formed after the dialysis finishes is for subsequent use;

Step 2. Preparation of modified bovine serum albumin-chitosan particles: Dissolve chitosan into an aqueous acetic acid solution with a concentration of 1.0-5.0%, then add the mixed solution B in step 1, stir and mix evenly at room temperature, The mixture is then dropped into a sodium hydroxide solution with a concentration of 1 to 4 mol/L to obtain spherical particles, and then the spherical particles are immersed in an epichlorohydrin solution with a pH value of 9.0 to 12.0. After the reaction is completed, that is, To obtain modified bovine serum albumin-chitosan spherical particles cross-linked with epichlorohydrin;

Step 3. Degradation of methyl red by modified bovine serum albumin-chitosan spherical particles: using acetic acid-sodium acetate as a buffer solution, the modified bovine serum albumin prepared in step 2 was added to the methyl red solution- Chitosan spherical particles, let stand, and the methyl red solution can gradually change from orange to colorless.

About Us

The production base is located in Zhangqiu chemical industry park and Tai’an high-tech chemical industry park. laboratory and workshop in strict accordance with the GMP standard and the product fit national ISO9001 and ISO2000 standards.

“Zhishang” products are exported to Europe, North and South America, the Middle East, Asia Pacific and Africa area, so as to establish a long-term and stable cooperation relationship with customer in the world.

Company Info
  • Business Type: Manufacturer
  • Product Range: Additive , Chemical Auxiliary & Catalyst , Organic Chemicals
  • Products/Service: Organic Intermediate,Inorganic Chemistry, APIs, Dyestuffs And Pigments, Fragrance And Spices, Food Additives
  • Total Employees: 51~100
  • Capital (Million US $): 10000000RMB
  • Year Established: 2016
Production Capacity
  • No. of Production Lines : 8
  • No. of QC Staff : 5 -10 People
  • OEM Services Provided : yes
  • Factory Size (Sq.meters) : 3,000-5,000 square meters
  • Certificate: ISO9001 , CE , GMP , API , MSDS
  • Factory Location : Diao Town Industry Park, Zhangqiu City, Jinan City, Shandong Province, China.


Pre-Sales Service

* Prompt reply and 24 hours online, professional team to provide best price and high quality product.

* Sample testing support.

* Every batch of products will be tested to ensureits quality.

*The packing also can be according the customers` requirment.

*Any inquiries will be replied within 24 hours.

*we provide Commerical Invoice, Packing List, Bill of loading, COA , Health certificate and Origin certificate. If your markets have any special requirements, let us know.


After-Sales Service

*The fact of logistics information monitoring.

* Any questions about the product can be consulted at any time.

*Product has any problem can return.


Do you accept sample order?

We will make samples before mass production, and after sample approved, we’ll begin mass production. Doing 100% inspection during production, then do random inspection before packing.



You can get free samples for some products,you only need to pay the shipping cost or arrange a courier to us and take the samples. You can send us your product specifications and requests,we will manufacture the products according to your requests.

What’s your MOQ?

Our MOQ is 1kg. But usually we accept less quantity such as 100g on the condition that sample charge is 100% paid.

Do you supply product report?

Yes. We’ll give you product analysis report before shipping.

  Is there a discount?

Different quantity has different discount.


1. ≤50kg, Express delivery recommended, usually called as DDU service;

2. ≤500kg, Air shipping recommended, usually called as FOB, CFR, or CIF service;

3. >500kg, sea shipping recommended, usually called as FOB, CFR, or CIF service;

4. For high value products, please select air shipping and express delivery for safe.

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