Buyers comparing methyltrioctylammonium chloride grades quickly discover that the name on the label does not tell the whole story. Products sold under this name, under the trade-style designation Aliquat 336, or simply as “trioctyl methyl ammonium chloride” can differ significantly in alkyl chain composition, assay method, water content and impurity profile. This guide explains how the main grades on the market differ, which specification parameters matter for common applications, and what to check on a certificate of analysis before committing to a commercial volume.
What Methyltrioctylammonium Chloride Is
Methyltrioctylammonium chloride (CAS 5137-55-3) is a quaternary ammonium salt carrying one methyl group and three C8 (octyl) chains on the central nitrogen, paired with a chloride counterion. The three long alkyl chains make the cation strongly lipophilic, so the salt partitions readily into organic phases while still pairing with anions from an aqueous phase. This combination is why the compound is commonly explored as a phase transfer catalyst, as an extractant for metal ions, and as a hydrophobic cation in ionic liquid and deep eutectic solvent research.
At room temperature the material is typically a viscous amber liquid or a soft paste rather than a free-flowing solid. Viscosity, color and handling behavior all vary with water content and chain distribution, which is one reason grade selection matters more for this product than for crystalline quats such as TBAB.
Common Methyltrioctylammonium Chloride Grades on the Market
Commercial supply generally falls into three broad tiers, and understanding methyltrioctylammonium chloride grades in these terms makes quotations much easier to compare.
Technical or Aliquat 336-type grade. Historically, material of this type has been produced from mixed C8-C10 fatty alkyl feedstocks, so the “trioctyl” name is nominal: the product is a mixture dominated by C8 chains with a meaningful C10 fraction. Assay is often quoted around 88-90 percent quaternary content with the balance being water and minor amounts of related amines. For solvent extraction and many industrial catalysis uses, this mixed-chain grade can be considered fully adequate, and it is usually the most economical option. Our earlier article on Aliquat 336 in metal solvent extraction covers this application area in more detail.
Standard synthesis grade. This tier targets a defined single compound with tighter chain distribution and a higher quaternary assay, commonly specified at 95 percent minimum or better. It suits organic synthesis work where stoichiometry matters and where variable chain length could complicate workup or analytical interpretation.
High-purity or research grade. For electrochemistry, ionic liquid studies and analytical applications, buyers may require 97-98 percent minimum assay together with low water, low residual tertiary amine and tightly controlled halide by-products. This grade commands a premium and is usually produced or purified in smaller campaigns, so lead times should be confirmed early.
Specification Parameters That Matter on the COA
Whatever the tier, a meaningful specification for this product should address the following points.
Assay and assay method. Quaternary content may be reported by non-aqueous titration, by ion chromatography or by nitrogen determination, and the numbers are not directly interchangeable. Always confirm which method sits behind the certificate figure.
Chain distribution. If your process depends on a defined C8 compound rather than a C8-C10 mixture, ask for a gas chromatography breakdown of the alkyl distribution, not just a total assay.
Water content. Karl Fischer water is typically limited to a few percent in technical material and well below 1 percent in higher grades. Water strongly affects viscosity and can matter in moisture-sensitive chemistry.
Free amine and amine hydrochloride. Residual trioctylamine and its hydrochloride are the most common process-related impurities. They can interfere with extraction selectivity and may carry odor, so a stated limit is worth requesting.
Color and appearance. APHA or Gardner color limits give a quick indication of oxidation history and thermal stress during manufacture. Darkening over storage may be evaluated as an early sign of degradation.
Heavy metals and residual solvents. These become relevant when the product is used in electronics-adjacent work or when downstream customers impose their own limits; they are usually available on request rather than on the standard COA.
Matching the Grade to the Application
As a practical rule: hydrometallurgy and solvent extraction programs can usually start with technical mixed-chain material; phase transfer catalysis in fine chemical synthesis is commonly run on standard synthesis grade; and electrolyte, sensor or publication-oriented research generally justifies high-purity material. Because this product line sits alongside other quaternary ammonium catalysts, it is worth reviewing the broader catalysis and synthesis chemicals range when qualifying a supplier, so that one audit can cover several related items. Detailed typical values for our own offer are listed on the methyltrioctylammonium chloride product page.
When scaling up, request a wet sample from the actual production line rather than a retained laboratory sample, and run it through your own extraction or reaction screen before fixing the specification in the contract. Small differences in chain distribution or free amine can shift phase behavior in ways a paper comparison will not reveal.
Why AXIA CHEM
AXIA CHEM supplies methyltrioctylammonium chloride and a broad portfolio of quaternary ammonium salts to industrial and research buyers across the Middle East and worldwide. We provide batch-specific certificates of analysis, pre-shipment samples, flexible pack sizes from drums to IBCs, and documentation support for GCC import requirements. Our technical team responds quickly on specification questions and can align COA parameters with your internal acceptance criteria before the first order. To discuss grades, specifications or current lead times, contact AXIA CHEM for a quotation.
Regulatory disclaimer: These products are supplied for research, formulation development, industrial and non-regulated applications. Final suitability for pharmaceutical, oral care, cosmetic, food-contact or biocidal applications shall be verified by the buyer according to local regulations. AXIA CHEM does not claim that any product is FDA approved, USP/EP certified, GMP grade or approved for any specific regulated end use unless otherwise confirmed in writing with supporting documentation.