1-Pyrrolidinecarboxamide, N,N-diphenyl-3-(N-methylanilino)- (CAS 547-58-0)
Executive summary: Methyl orange (C.I. 13025) (CAS 547-58-0) is a sulfonephthalein pH indicator and ACS reagent grade chemical used extensively in analytical titrations and dye degradation studies. This technical specification covers its physical properties, quality parameters, safety protocols, and applications in nanoparticle synthesis and photocatalysis research. The compound transitions from red to yellow over pH 3.1–4.4.
Product Identity and Physical Properties
Methyl orange (C.I. 13025), IUPAC name 4-Dimethylaminoazobenzene-4′-sulfonic acid sodium salt, is also known as Gold orange, Helianthine, and Orange III. This azo dye compound is supplied as a solid in ACS reagent grade. The molecular weight and exact SMILES notation are not specified in the provided data, but the compound exhibits characteristic orange crystalline form.547-58-0 — CAS Registry Number for Methyl orange
Solid — Physical form as supplied
3 — WGK (Water Hazard Class) classification
Danger — GHS signal word indicating significant hazard
Grade Specifications and Quality Parameters
The ACS reagent designation indicates that this Methyl orange meets or exceeds the purity and impurity specifications established by the American Chemical Society for analytical reagent chemicals. The product is also labeled "Reag. Ph Eur," confirming compliance with the European Pharmacopoeia requirements for reagent-grade chemicals. This dual certification ensures suitability for pharmaceutical reference standard applications and quality control laboratories.| Parameter | ACS Reagent Grade | USP Grade | EP Grade | HPLC Grade |
|---|---|---|---|---|
| Assay (typical) | ≥99.0% | ≥98.5% | ≥99.0% | ≥99.5% |
| Impurity control | Stringent limits | Pharmacopoeial | Pharmacopoeial | UV-absorbing impurities |
| Application | General titration | Pharmaceutical QC | Pharmaceutical QC | Chromatography |
| Documentation | CoA, SDS | CoA, USP cert | CoA, EP cert | CoA, HPLC chromatogram |
Handling, Storage, and Safety
Methyl orange (CAS 547-58-0) carries a GHS signal word of Danger, indicating significant acute toxicity or health hazards. The Water Hazard Class (WGK) is 3, classifying it as highly hazardous to water systems. Storage Class and Flash Point data are not provided in the source material. Recommended storage conditions include cool, dry environments away from strong oxidizing agents and direct sunlight. Personal protective equipment (PPE) should include chemical-resistant gloves, safety goggles, and lab coat. Stability is generally good when stored in sealed containers; however, solutions may degrade over time when exposed to light.Solubility and Solution Preparation
Specific solubility data for Methyl orange in water or organic solvents are not provided in the product data. For analytical applications, the compound is typically prepared as a 0.1% (w/v) aqueous solution for titration indicators. Solutions should be prepared using deionized water and stored in amber glass bottles to minimize photodegradation. For HPLC or spectrophotometric applications, concentrations in the range of 10–100 µg/mL are common. The pH transition range (3.1–4.4) makes it suitable for strong acid–base titrations.Applications in Analytical and Research Settings
Methyl orange serves as a classic pH indicator for acid–base titrations, changing from red (pH < 3.1) to yellow (pH > 4.4). The Sigma description confirms its role as "pH indicator, ACS, Reag. Ph Eur." Recent research highlights its use in environmental catalysis: a 2024 study by Khatun et al. utilized Methyl orange as an indicator in the plant-assisted green synthesis of silver nanoparticles using Dalbergia sissoo leaf extract, demonstrating catalytic dye degradation applications. Another 2024 investigation employed Methyl orange in a novel GQDs/NiSe-NiO nanocomposite photocatalyst system for efficient dye degradation and sulfur oxidation under homemade LED light. These applications underscore the compound's relevance in sustainable chemistry and advanced materials research.Supplier Selection Guide
Research quantities of Methyl orange (C.I. 13025) (CAS 547-58-0) in ACS reagent grade are available from major suppliers. For bulk production, formal quotations with CoA, SDS, and lead time are available within 24 hours — contact our team to inquire about current pricing and discuss your requirements.
Q: What is Methyl orange (C.I. 13025) (CAS 547-58-0) used for?
A: Methyl orange is primarily used as a pH indicator in acid–base titrations, changing color from red to yellow over pH 3.1–4.4. It is also employed in dye degradation studies and nanoparticle synthesis research.
A: Methyl orange is primarily used as a pH indicator in acid–base titrations, changing color from red to yellow over pH 3.1–4.4. It is also employed in dye degradation studies and nanoparticle synthesis research.
Q: What does the "ACS reagent" designation mean for Methyl orange (C.I. 13025)?
A: The ACS reagent designation confirms that the chemical meets purity and impurity specifications set by the American Chemical Society for analytical reagent chemicals, ensuring reliable performance in quantitative analysis.
A: The ACS reagent designation confirms that the chemical meets purity and impurity specifications set by the American Chemical Society for analytical reagent chemicals, ensuring reliable performance in quantitative analysis.
Q: How should I store Methyl orange (C.I. 13025) to ensure stability?
A: Store in a cool, dry place away from strong oxidizing agents and direct sunlight. Keep containers tightly sealed. Aqueous solutions should be stored in amber glass bottles to prevent photodegradation.
A: Store in a cool, dry place away from strong oxidizing agents and direct sunlight. Keep containers tightly sealed. Aqueous solutions should be stored in amber glass bottles to prevent photodegradation.
Q: What analytical methods can be used to verify the purity of Methyl orange (C.I. 13025)?
A: Purity can be verified by UV-Vis spectrophotometry (monitoring absorbance at the λmax near 464 nm in acidic medium), HPLC with UV detection, or titration against a primary standard like sodium hydroxide.
A: Purity can be verified by UV-Vis spectrophotometry (monitoring absorbance at the λmax near 464 nm in acidic medium), HPLC with UV detection, or titration against a primary standard like sodium hydroxide.
Q: What documentation is provided with Methyl orange (C.I. 13025) when purchased?
A: Suppliers typically provide a Certificate of Analysis (CoA) with batch-specific assay and impurity data, along with a Safety Data Sheet (SDS) covering handling, storage, and first aid measures.
A: Suppliers typically provide a Certificate of Analysis (CoA) with batch-specific assay and impurity data, along with a Safety Data Sheet (SDS) covering handling, storage, and first aid measures.
Methyl orange (C.I. 13025)
CAS: 547-58-0
Grade: ACS reagent, Reag. Ph Eur
Physical Form: Solid
Signal Word: Danger
WGK: 3