Phthalic acid

CAS 88-99-3C6H4-1Acids & Bases

Phthalic acid (CAS 88-99-3), a white crystalline solid with the formula C6H4-1,2-(CO2H)2 and a molecular weight of 166.13 g/mol, is a crucial dicarboxylic acid. It serves as a key intermediate in the synthesis of various organic compounds, including plasticizers, dyes, and pharmaceuticals. Its chemical structure makes it a valuable building block in organic synthesis, facilitating the creation of complex molecules.

IUPAC: 1,2-Benzenedicarboxylic acid
Synonyms: 1,2-Benzenedicarboxylic acid2-(CO2H)2

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Phthalic acid (C6H4-1) — chemical structure, CAS 88-99-3; Chemistry, fine chemical supplied by Tech Serve Solutions

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01 /Applications

Plasticizer Synthesis

Phthalic acid is a primary precursor for the production of phthalate esters, widely used as plasticizers to enhance the flexibility and durability of PVC and other polymers.

Dye Manufacturing

It is employed in the synthesis of various dyes and pigments, contributing to the vibrant colours used across industries such as textiles and printing inks.

Pharmaceutical Intermediates

Phthalic acid acts as a building block in the synthesis of certain pharmaceutical compounds, contributing to the development of active pharmaceutical ingredients.

Organic Synthesis

As a versatile organic building block, it is utilised in academic and industrial research for the creation of diverse organic molecules and novel materials.

02 /Properties

Molecular weight	166.13
Linear formula	C6H4-1,2-(CO2H)2
Assay	≥99.5%
Grade	ACS reagent
Impurities tested	≤0.05% insolubles≤0.5% water
Melting point	210-211 °C (dec.)(lit.)

03 /Safety & handling

GHS hazard pictogram: Harmful / irritant (GHS07) — Harmful / irritant

Warning

Hazard statements

H315Causes skin irritation
H319Causes serious eye irritation
H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust, fume, gas or vapours
P305IF IN EYES

Protective equipment	dust mask type N95 (US), Eyeshields, Gloves
Water hazard class (WGK, DE)	3
Hazard codes (EU)	Xi
Risk statements (R)	36/37/38
Safety statements (S)	26
Cation traces	Fe: ≤0.001%heavy metals: ≤0.001%
Anion traces	chloride (Cl-): ≤0.001%nitrate (NO3-): ≤0.005%sulfate (SO42-): ≤0.005%
Ignition residue	≤0.02%

Hazard information is provided for guidance. Always consult the product Safety Data Sheet (SDS), available on request, before handling.

04 /Identifiers & registry

CAS number

88-99-3

MDL number

MFCD00002467

Beilstein registry

608199

05 /Quality & supply

Documentation

Every batch ships with a Certificate of Analysis covering assay, identity and purity; the grade is confirmed against your enquiry. Safety Data Sheets and technical data sheets are available on request.

Supply & logistics

Samples for technical evaluation; bulk MOQ by grade and packaging. In-stock material ships in 7–10 working days, worldwide, with full export documentation.

06 /Frequently asked questions

What is Phthalic acid used for?

Phthalic acid is primarily used in the synthesis of plasticizers, dyes, pigments, and as an intermediate in pharmaceutical manufacturing and general organic synthesis.

What is the CAS number and chemical formula for Phthalic acid?

The CAS number for Phthalic acid is 88-99-3, and its linear chemical formula is C6H4-1,2-(CO2H)2.

What grade and purity does Tech Serve Solutions supply for Phthalic acid?

Tech Serve Solutions supplies Phthalic acid in ACS reagent grade with an assay of ≥99.5%.

How should Phthalic acid be handled safely?

Phthalic acid is an irritant to the skin, eyes, and respiratory system. Use appropriate personal protective equipment, including a dust mask (type N95), eyeshields, and gloves, and handle in a well-ventilated area to avoid inhalation.