DNQ Sodium Salt vs DNQ-Cresol Ester: Which One Do You Need?

Two CAS numbers, two supply-chain entry points

DNQ chemistry serves two industries from Orion's portfolio: UV CtCP offset plate coatings and g-line/i-line electronic photoresists. Buyers enter the supply chain at different stages depending on whether they synthesise in-house or buy a ready photoactive resin.

The distinction is structural, not a purity difference. CAS 64173-96-2 is the upstream salt — the water-soluble DNQ intermediate you dissolve, convert, or esterify before it becomes photoactive in a coating. CAS 3770-97-6 is the downstream product — DNQ already esterified with cresol resin into a one-pack diazo polymer you dissolve directly into solvent and coat.

CAS 64173-96-2: the water-soluble DNQ building block

Orion Freedom 2-1-4 is the sodium salt of 2-diazo-1-naphthol-4-sulphonic acid. It arrives as a yellow powder, soluble in water, with 98.0% minimum assay and 2.5% maximum moisture on the certificate of analysis.

This grade sits at the start of the DNQ value chain. Typical uses include:

• Coating synthesis — dissolved as the core DNQ active in custom coating programmes
• Downstream conversion — transformed to sulphonyl chloride for further esterification into one-pack resins or DNQ-THBP photoactive compounds (PACs)
• Electronic photoresist programmes — supplied as a diazonaphthoquinone active where the formulator controls resin selection and esterification chemistry in-house

If your team runs its own sulphonyl chloride conversion, esterification, or novolak blending, CAS 64173-96-2 is the correct entry point. You are buying a building block, not a finished coating resin.

For full specifications, see the Orion Freedom 2-1-4 product page.

CAS 3770-97-6: the esterified one-pack DNQ–cresol resin

Orion Freedom Plus 1413 (Freedom Plus One Pack) is the esterified DNQ–cresol resin registered under CAS 3770-97-6. DNQ is already esterified with suitable cresol resin — no separate resin addition is required. You dissolve the one-pack in your chosen solvent blend and proceed to coating.

This grade is built for plate-coating lacquers and photoresist formulations where the photoactive resin is needed in finished form:

• Conventional positive UV CtCP offset plates — the main diazo polymer in coating lacquers for computer-to-conventional-plate systems on electro-chemically grained, anodised aluminium
• In-house plate coating lines — supplied as dry powder or pre-dissolved solutions (30%, 12%, or 7–8% RTU) matched to reverse roll, forward roll, slot die, or whirler equipment

Spectral sensitivity runs 365–405 nm for standard UV laser plate setters. Target coat weight is 1.7–1.8 g/m². Plates are positive-working and self-cure in 24 hours under yellow safe light.

If you coat plates or formulate resists and want a ready photoactive resin — not a salt to esterify yourself — CAS 3770-97-6 is the correct CAS to specify.

For coating parameters and supply formats, see the Orion Freedom Plus One Pack product page.

How the two grades relate in the DNQ value chain

The relationship is sequential, not competitive:

Orion manufactures both grades at its works in Karad, Maharashtra. A plate coater buying Freedom Plus 1413 does not need to handle the sodium salt. A formulator running custom DNQ synthesis buys the salt and builds downstream chemistry in-house.

For the broader chemistry context, see What is diazonaphthoquinone (DNQ)?.

Which grade do you need?

Choose CAS 64173-96-2 (Freedom 2-1-4) if you:

• Run in-house DNQ synthesis or sulphonyl chloride conversion
• Formulate custom DNQ esters or DNQ-THBP PAC grades from a water-soluble starting material
• Need a documented DNQ salt with batch COA, MSDS, and TDS for a synthesis programme

Choose CAS 3770-97-6 (Freedom Plus 1413) if you:

• Coat UV CtCP offset plates and need a ready esterified diazo polymer
• Want a one-pack resin dissolved directly into solvent — no separate cresol resin addition
• Operate roll, slot die, or whirler coating equipment and need a grade matched to your coater format

You may need both if you are a vertically integrated manufacturer: the salt for photoresist PAC synthesis and the one-pack ester for a separate plate-coating line. Most buyers need only one entry point.

Documentation and procurement for both grades

Both grades ship with a certificate of analysis (COA) per batch. MSDS and TDS are available on request or from each product page. Minimum order quantity is 10 kg, with supply from India and export worldwide.

When qualifying either grade, request a trial batch COA before production volumes. Compare assay, moisture, and appearance against your incoming specification.

For a step-by-step qualification workflow, see How to Qualify a New DNQ Supplier.