Isononanoic Acid (INA) — CAS 3302-10-1 / 26896-18-4, 3,5,5-Trimethylhexanoic Acid 99.93%, Metal Ions ≤5 mg/kg

Isononanoic Acid (INA) - 3,5,5-Trimethylhexanoic Acid, CAS 3302-10-1

99.93% single-isomer purity · Pt-Co 3.2 water-white · Water 0.01% · Na/Fe/Cu/Ca/Zn each ≤5 mg/kg · 35,000 t/a integrated capacity

⚠️ Important for REACH filings, customs declarations and procurement contracts.

Two CAS numbers circulate for this product, and they are not interchangeable in regulatory paperwork:

CAS 3302-10-1 - 3,5,5-trimethylhexanoic acid. The pure single isomer. Because Sinolook's material tests 99.93% 3,5,5-TMH by GC, this is the technically accurate identifier for the substance you actually receive, and the one we recommend for REACH registration, SDS authoring and shipping documents.

CAS 26896-18-4 - isononanoic acid. The commercial registry entry covering Oxo-derived mixed branched C9 acid. Widely used in catalogues, tariff codes and legacy purchase specifications. We list it as an alias so your ERP and search records match.

Our COA states both. If your quality agreement or REACH dossier is written against only one of them, tell us at the enquiry stage and we will align the documentation before shipment. Full isomer background: Isononanoic Acid Structure & Isomers →

❄️ Why the ≤5 mg/kg metal ion limit matters. Residual Na, Fe, Cu, Ca and Zn act as transesterification and oxidation catalysts inside sealed compressors. In a POE refrigeration lubricant they accelerate ester hydrolysis, raise total acid number in service, and promote copper plating on bearing surfaces. Acid feedstock with uncontrolled metal content is one of the most common - and least visible - root causes of POE oil TAN drift. Detail: INA Polyol Esters in Refrigeration Compressors →

01Crude oil - own import quota, own tank farm and pipeline

02Refining - integrated refinery yields MTBE

03Cracking - MTBE cracked to high-purity isobutene

04DIB production - catalytic dimerisation to di-isobutene

05Hydroformylation - Oxo synthesis to C9 aldehyde

06Oxidation - aldehyde oxidised to isononanoic acid

❄️ 1. Polyol Ester (POE) Refrigeration & Compressor Lubricants

The single largest outlet. INA is esterified with pentaerythritol (PE) or trimethylolpropane (TMP) to give PE tetraisononanoate and TMP triisononanoate - the base stocks of ISO VG 32 / 46 / 68 / 74 / 100 refrigeration oils for HFC and HFO systems (R-134a, R-410A, R-32, R-1234yf). The branched C9 chain delivers pour points below −40 °C, a high viscosity index, and refrigerant miscibility that mineral oils cannot match.

🔗 INA in Synthetic Ester Lubricants · POE Esters in Refrigeration Compressors

🎨 2. Metal Isononanoate Salts - Driers, PU Catalysts, PVC Co-Stabilisers

Cobalt, zirconium, manganese, calcium, zinc, bismuth and cerium isononanoates. The extra methylene over the C8 octoate family gives higher hydrocarbon solubility, so drier concentrates can be built at 6–18% metal without cold-storage precipitation. Pt-Co 3.2 feedstock is what makes a water-white drier possible for white and pastel alkyd systems.

⚠️ Be careful here: cobalt isononanoate still carries Repr. 1B from the cobalt ion. Choosing a non-Repr. 1B acid does not clear the cobalt salt. The substitution benefit is real for Zr, Bi, Zn, Ca and Mn derivatives - not for Co.

🔗 Metal Isononanoate Coating Driers

🛢️ 3. Metalworking Fluids & Rust Preventives

Used as an additive in cutting, grinding and forming fluid concentrates, providing boundary lubrication, EP film formation and rust inhibition. Neutralised with amines it yields water-soluble soaps for semi-synthetic and synthetic coolants, where the branched chain resists the soap gelling that linear C9 acids cause in hard water.

🧴 4. Surfactants, Emulsifiers & Personal Care Esters

Ethoxylation, amidation or sulfonation yields branched non-ionic and anionic surfactants with low CMC, fast wetting and low foam - for industrial cleaners, degreasers, agrochemical adjuvants and oilfield chemicals. Short-chain isononanoate esters also serve as emollients and spreading agents in skin-care and hair-care formulations.

🧱 5. Alkyd Resin Modifier & Non-Phthalate Plasticiser Intermediate

As a chain-stopping branched monoacid in alkyd and saturated polyester synthesis, INA lowers backbone crystallinity, improves aliphatic solvent solubility and extends cured-film flexibility - useful in low-VOC alkyd reformulation. Esterified with neopentyl glycol or TMP it also gives non-phthalate diester and triester plasticisers for flexible PVC cable and film.

✅ Reference formulations for ISO VG 32 / 46 / 68 / 74 / 100 refrigeration base oils (VI ≥ 90, pour point down to −45 °C, acid value ≤ 0.03 mg KOH/g, water ≤ 100 ppm)

✅ Esterification stoichiometry and catalyst selection guidance for PE / TMP isononanoate

✅ Acid substitution package for blenders migrating from 2-EHA - comparative regulatory summary plus charge conversion tables

✅ Qualification samples 0.5–5 kg, shipped with full batch COA

📁 Shipped with every consignment:

📄 EU CLP-format SDS (16 sections, GHS Rev. 9)

📄 Batch COA from CNAS-accredited laboratory - including the full metal ion suite

📄 REACH registration confirmation and non-SVHC letter

📄 Non-HAP declaration and TSCA inventory confirmation

📄 Comparative INA vs 2-EHA regulatory summary (on request)

⚠️ Flash point ≈ 105–113 °C - Combustible Liquid Class III-B, and lower than both 2-EHA and NDA. Keep away from open flame and heat sources. Mild skin and eye irritant (H315 / H319): nitrile gloves ≥0.1 mm plus safety goggles for all handling. Flush skin or eye contact with water for at least 15 minutes; seek medical advice for eye contact.

Q1. Should my purchase order say CAS 3302-10-1 or 26896-18-4?

Either will reach the same material from us, but they are not equivalent in regulatory documents. Because this grade is 99.93% single isomer, 3302-10-1 is the technically correct identifier and the one we recommend on SDS, REACH dossiers and customs declarations. Use 26896-18-4 if your existing quality agreement, ERP master data or tariff classification is already written against it - just tell us at enquiry stage so the COA and SDS match your paperwork.

Q2. Is isononanoic acid used to make DINP plasticiser?

No. DINP is made from isononanol (the C9 alcohol, CAS 27458-93-1), not from isononanoic acid. Both come from C8 olefin via Oxo synthesis, but the aldehyde intermediate is hydrogenated to give the alcohol and oxidised to give the acid. If you need the DINP precursor you need the alcohol, not this product.

🔗 Isononanoic Acid vs Isononanol - Clearing the Confusion →

Q3. What stoichiometric change is needed when replacing 2-EHA with INA?

Acid value drops from ≈389 to ≈354.5 mg KOH/g, so you need roughly 9–10% more INA by weight per mole of metal salt or ester produced. Always calculate from the batch COA acid value rather than the theoretical figure. The resulting metal isononanoates carry slightly higher molecular weight and better aliphatic solvent solubility than the equivalent octoates. Ask us for the conversion tables.

Q4. Why does the metal ion spec matter if I am only making coating driers?

For solventborne driers it matters much less - colour and acid value dominate. The ≤5 mg/kg suite is aimed at POE refrigeration lubricant and electronic-grade ester producers, where trace Na, Fe and Cu catalyse ester degradation inside sealed systems. If your application is drier synthesis, the value you should be looking at is the Pt-Co 3.2 colour, which is what makes water-white concentrates possible for white and pastel alkyds.

Q5. Is the correct name 3,5,5-trimethylhexanoic acid or trimethylheptanoic acid?

3,5,5-trimethylhexanoic acid. The molecule has nine carbons in total, but the longest continuous chain containing the carboxyl group is six - hence hexanoic, with methyl groups at 3, 5 and 5. "Trimethylheptanoic acid" appears in some supplier documents and is a naming error; do not carry it into REACH notifications or contracts.

Q6. What are the lead time, MOQ and sample terms?

Qualification samples of 0.5–5 kg ship with a full batch COA. Commercial MOQ is one 200 kg drum; IBC, ISO tank and flexitank available for volume programmes. Lead time depends on port and packing mode - send your target volume, destination port and required documentation set and we will quote within 24 hours.

📩 Request Price, Sample & Full Document Package

Tell us your target volume, destination port, application (POE ester / drier / MWF / surfactant) and which CAS number your paperwork uses. We reply within 24 hours with pricing, batch COA including the metal ion suite, EU CLP SDS and the regulatory letter set. Qualification samples 0.5–5 kg.