Description

p-Methoxybenzenesulfonic Acid is a versatile aromatic sulfonic acid derivative, serving as a key intermediate and catalyst in advanced organic synthesis. Its value lies in its dual functionality as a mild acid catalyst and a building block for introducing the p-methoxyphenylsulfonyl moiety. This compound is essential for manufacturers and R&D teams in the pharmaceutical, agrochemical, and specialty chemical industries seeking reliable, high-purity synthetic reagents.

Application

• Pharmaceutical Intermediate: Used in the synthesis of active pharmaceutical ingredients (APIs), particularly for constructing sulfonamide-based drug molecules.
• Catalyst in Organic Reactions: Acts as a mild, water-tolerant Brønsted acid catalyst for esterifications, condensations, and protection/deprotection reactions.
• Agrochemical Synthesis: Serves as a precursor for herbicides, fungicides, and plant growth regulators that incorporate sulfonic acid or sulfonate ester groups.
• Dye and Pigment Manufacturing: Employed in the production of sulfonated dyes and colorants to enhance solubility and fiber affinity.
• Polymer Modification: Used to introduce sulfonic acid groups into polymers, potentially for ion-exchange resins or proton-conducting membranes.
• Research & Development: A valuable reagent in academic and industrial labs for method development and exploring new synthetic pathways.

Basic Information

Product Name	p-Methoxybenzenesulfonic Acid
CAS No.	5857-42-1
Molecular Formula	C7H8O4S
Molecular Weight	188.20 g/mol
Synonyms	4-Methoxybenzenesulfonic Acid; p-Anisolesulfonic Acid; 4-Anisolesulfonic Acid; 4-Methoxyphenylsulfonic Acid; Benzenesulfonic acid, 4-methoxy-; PAS; PMBSA
EINECS	227-477-8

Quality Control

Our p-Methoxybenzenesulfonic Acid is manufactured under a strict quality management system. Each batch undergoes comprehensive analytical testing, including assay (HPLC), identification (IR), and impurity profiling, to ensure it meets exacting standards for purity and consistency. Certificates of Analysis (COA) are provided with every shipment and are available upon request.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). Due to its hygroscopic nature, the container must be kept tightly sealed to minimize exposure to atmospheric moisture.

Specification

Item	Specification
Appearance	White to off-white crystalline powder
Identification (IR)	Conforms to structure
Assay (HPLC)	≥ 98.0%
Loss on Drying	≤ 2.0%
Melting Point	Contact for details
Heavy Metals	< 20 ppm

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.