Glacial is a purity statement, not a brand
Acetic acid (CH₃COOH, CAS 64-19-7) is described as "glacial" when it is essentially water-free, at 99.5% or above. The name comes from its habit of forming ice-like crystals just below room temperature. Because the concentration is effectively fixed across industrial supply, what separates one glacial acetic acid from another is the impurity profile — and that is set by the grade you specify.
| Grade | Assay | Specified against | Typical use |
|---|---|---|---|
| Glacial, industrial | ≥99.5% | ASTM D1989 — low water, formic acid, iron | Chemical feedstock, textile processing, solvent |
| Glacial, pharmaceutical | ≥99.5% | BP or USP monograph | API synthesis, excipients, reagent |
| Glacial, food | ≥99.5% | FCC specification | Food acidulant and preservative |
| Diluted | 80% | Commercial dilution | Textile pH adjustment, industrial cleaning |
| Diluted | 30–56% | Various industrial | Water treatment, dilute acid duty |
| Vinegar | 4–16% | FCC / GMP | Food and culinary use |
The three glacial grades can carry the same 99.5% assay and very different price tags. That difference is the analysis and controls behind the certificate, not the acid content. Specify the monograph you need — BP, USP or FCC — rather than the word "pure", which means nothing on a purchase order.
Key physical properties
| Property | Value |
|---|---|
| Chemical formula | CH₃COOH |
| CAS number | 64-19-7 |
| Molecular weight | 60.05 g/mol |
| Appearance | Colourless, transparent liquid |
| Odour | Sharp and vinegar-like |
| Melting point | 16.6 °C — solidifies at room temperature in winter |
| Boiling point | 118.1 °C |
| Flash point | 39 °C — flammable liquid |
| Auto-ignition temperature | 426 °C |
| Density at 20 °C | 1.05 g/cm³ |
| pKa | 4.76 — a weak acid |
| Miscibility | Fully miscible with water, ethanol and acetone |
The freezing problem, and how to buy around it
Glacial acetic acid freezes at 16.6 °C. That is not an edge case in Pakistan — it is a normal winter night in Lahore, Faisalabad, Sialkot and anywhere further north. Drums delivered in December can arrive as solid blocks, and a frozen IBC cannot be pumped.
- Plan winter deliveries into a heated or insulated store rather than an open yard
- Thaw by warm-room or warm-water jacket, never with a direct flame or an unregulated immersion heater — the flash point is only 39 °C
- Expect thawing to take considerably longer than intuition suggests, and build it into production planning
- Where the process tolerates it, an 80% diluted grade avoids the problem entirely, since it stays liquid well below freezing point
- For continuous users, trace-heated lines and a temperature-controlled tank are usually cheaper than repeated thawing downtime
This is worth raising with a supplier at enquiry stage. It changes the pack recommendation and sometimes the grade recommendation, and it is much easier to solve before the first winter delivery than after it.
Flammability changes how it is stored
Acetic acid is often grouped mentally with mineral acids, but its flash point of 39 °C puts it in a different category for storage and transport. It is a flammable liquid that is also corrosive, and both properties have to be designed for.
- Store away from ignition sources, in a ventilated area, separated from oxidising agents and strong alkalis
- Suitable materials — stainless steel 316, glass, HDPE and PTFE; aluminium is attacked and carbon steel discolours the product
- Bond and earth containers during bulk transfer, as for any flammable liquid
- Do not store alongside nitric acid, chromic acid, peroxides or permanganates
Where it is used, and what that implies for grade
For Pakistani buyers the largest domestic application is textile processing, where acetic acid controls dye bath pH. The parameters are consistent enough to specify against.
| Dyeing parameter | Typical range |
|---|---|
| Dye bath pH | 3.5–5.5, held with acetic acid |
| Acetic acid dosage | 1–4% on weight of fabric |
| Temperature | 95–100 °C for boil dyeing |
| Cycle time | 45–90 minutes |
| Dye classes | Acid, metal complex and chrome dyes |
- Chemical manufacture — the largest global use, as feedstock for vinyl acetate monomer, purified terephthalic acid, acetic anhydride and the acetate ester solvents
- Adhesives and coatings — via PVA, PVOH and VAE polymers used in wood glue, textile sizing, tile adhesive and paint binders
- Food processing — acidulant and preservative, requiring FCC grade
- Pharmaceutical manufacture — synthesis and pH control against BP or USP grade
- Water treatment — acetate dosing as a carbon source for biological denitrification
- Rubber and paper — latex coagulation and pH control in pulping
What to put on the RFQ
- Grade and monograph — "glacial, ≥99.5%, FCC" rather than "food grade acetic acid"
- Named limits where they matter — water content, formic acid, iron, chloride, and non-volatile residue
- Quantity per delivery and annual volume
- Pack type — HDPE or lined drum, IBC, or bulk — and delivery season, so freezing can be planned for
- Delivery city and whether the receiving store is heated
- Documentation — batch COA against the named monograph, MSDS, and import records where relevant
Checking quality on delivery
- Confirm assay and water content on the batch COA, with measured figures rather than "complies"
- Check for colour — glacial acetic acid should be water-white; any yellow cast suggests contamination or metal pickup
- Formic acid content is the parameter most often overlooked and most likely to affect a sensitive synthesis
- For FCC, BP or USP material, confirm the certificate names the monograph and edition rather than describing the grade in general terms
- Verify the lot number ties to the drum or IBC label before offloading
What drives the price
- Methanol and carbon monoxide feedstock costs, since methanol carbonylation is the dominant production route worldwide
- Grade — pharmaceutical and food grades carry the cost of tighter analysis and controlled handling
- Pack format and whether packaging is returnable
- Freight and delivery city, plus heated storage where a winter delivery requires it
- Exchange rate and import duty, as Pakistan is supplied largely by import
- Order regularity, with scheduled call-offs pricing differently from spot purchases
Sourcing considerations in Pakistan
- Most industrial glacial acetic acid reaching Pakistan is imported, so confirm availability date alongside price
- It travels as a flammable and corrosive material — check that the transport arrangement reflects both properties, not just the corrosive one
- Ask for the manufacturer name and origin on the documentation where batch-to-batch consistency matters to your process
- For food and pharmaceutical use, keep the monograph reference in the purchase record; it is what an audit will ask for