1-(4-Sulfonphenyl)-3-methyl-5-pyrazolone 98%Min Light yellow crystalline powder RC00075

Manufacturer: Hangzhou Royalchem Co.,LTD.

Website:  www.cnroyalchem.com

Chemical Name:

Preferred IUPAC Name:  5-Methyl-2-(4-sulfophenyl)-2,4-dihydro-3H-pyrazol-3-one

Common Names:

1-(4-Sulfophenyl)-3-methyl-5-pyrazolone

3-Methyl-1-(p-sulfophenyl)-2-pyrazolin-5-one

PMP (Pyrazolone Methyl Para Sulfonic acid)

PHMS (Pyrazolone Hydrate Methyl Sulfonic acid - referring to hydrated forms)

CAS Registry Number:  89-36-1

Synonyms:

4-(3-Methyl-5-oxo-4,5-dihydro-1H-pyrazol-1-yl)benzenesulfonic acid

Benzenesulfonic acid, 4-(3-methyl-5-oxo-2-pyrazolin-1-yl)-

5-Methyl-1-p-sulfophenylpyrazolone

Pyrazolone p-acid (deprecated, but sometimes seen)

Molecular Formula:  C₁₀H₁₀N₂O₄S

Molecular Weight:  254.26 g/mol (Anhydrous)

Appearance:  Typically a  cream to light yellow crystalline powder  or crystals. Color can vary slightly between batches/suppliers but should be pale.

Assay (Purity):  Usually ≥  97.0%  or ≥  98.0%  by HPLC or titration. High purity is critical for consistent dye synthesis.

Hydration State:  Most commonly supplied as the  Monohydrate  (C₁₀H₁₀N₂O₄S·H₂O, MW 272.28 g/mol). The anhydrous form is hygroscopic and less stable.

Solubility:

Freely soluble in  water  (primary application).

Slightly soluble in alcohol.

Practically insoluble in non-polar organic solvents (e.g., benzene, chloroform).

Melting Point:  Generally decomposes before melting (around 300°C or higher). Reported values vary (e.g., >250°C dec., >300°C dec.).

pH (Aqueous Solution):  Typically acidic due to the sulfonic acid group (e.g., pH ~2-3 for a saturated solution or 1% solution).

Loss on Drying (LOD):  Typically specified (e.g., ≤ 0.5% for anhydrous forms, or ≤ 7.0% for monohydrate forms). Critical for accurate weighing.

Sulfated Ash/Residue on Ignition:  Usually specified (e.g., ≤ 0.1% or ≤ 0.2%).

Impurities (Typical Specifications):

Related Substances (HPLC):  Total ≤ 1.0% - 2.0% (often specifying limits for isomers or degradation products if significant).

Heavy Metals (as Pb):  ≤ 10 ppm or ≤ 20 ppm.

Iron (Fe):  ≤ 50 ppm or ≤ 100 ppm.

Chloride (Cl⁻):  ≤ 100 ppm or ≤ 200 ppm.

Sulfate (SO₄²⁻):  ≤ 500 ppm or ≤ 1000 ppm.

Applications:

Primary Use:  Key intermediate in the synthesis of  acid dyes  (e.g., tartrazine/Yellow 5),  reactive dyes ,  pigments , and  azo dyes/couplers  used in textiles, paper, food, cosmetics (depending on the final dye purity/regulation).

Acts as a coupling component in azo coupling reactions.

Storage:

Store in a  cool, dry, and well-ventilated place .

Keep container tightly  closed  to prevent moisture absorption (especially anhydrous form) and contamination.

Recommended temperature:  +15°C to +25°C  (59°F to 77°F). Avoid prolonged exposure to higher temperatures or humidity.

Shelf Life:  Typically  2 years  or more from the date of manufacture when stored properly under recommended conditions.

Packaging:  Commonly available in  25 kg  woven bags with inner polyethylene liners (HDPE/LDPE). Smaller quantities may be available (e.g., 1 kg, 5 kg).

Safety Information (GHS - Typical Hazards):

Hazard Statements:

H315: Causes skin irritation.

H319: Causes serious eye irritation.

H335: May cause respiratory irritation. (Sometimes)

H302: Harmful if swallowed. (Often)

Precautionary Statements:

P261: Avoid breathing dust/fume/gas/mist/vapours/spray.

P264: Wash skin thoroughly after handling.

P271: Use only outdoors or in a well-ventilated area.

P280: Wear protective gloves/protective clothing/eye protection/face protection.

P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

P302+P352: IF ON SKIN: Wash with plenty of soap and water.

P312: Call a POISON CENTER or doctor/physician if you feel unwell.