Few specialty aromatics punch above their weight quite like durene. On its own it is a modest white solid with a faint sweet odor - but it is the chemical starting point for pyromellitic dianhydride (PMDA), and through PMDA it reaches into the polyimide films inside your phone, the insulation on electric-vehicle motors, and the heat-resistant resins in aerospace electronics. This pillar guide brings together everything a buyer, formulator or engineer needs to understand about 1,2,4,5-tetramethylbenzene, with links to detailed articles on each topic.

🔬 What Is Durene?

Durene - systematically named 1,2,4,5-tetramethylbenzene, and also known as durol or sym-tetramethylbenzene - is a polymethylated benzene carrying four methyl groups arranged symmetrically around the ring. It has the molecular formula C₁₀H₁₄ and a molar mass of about 134.22 g/mol. At room temperature it is a colorless-to-white crystalline solid with a mild, camphor-like odor; it is practically insoluble in water but dissolves readily in alcohols, ethers, benzene and acetone.

Its single most important structural feature is symmetry. Because the four methyl groups occupy the 1, 2, 4 and 5 positions, the molecule has a center of symmetry that leaves two equivalent, unsubstituted positions. That geometry is exactly what makes durene the preferred raw material for producing PMDA - a point we return to below.

For the full identity record and technical documentation, see the Durene product page, and the authoritative entries at PubChem (CID 7269) and ECHA (EC 202-465-7).

✅ Key Properties at a Glance

The values below are useful orientation points. For certified specifications, purity grades and the SDS, always refer to the product page rather than reproducing them elsewhere.

Two practical consequences follow from these numbers. First, because durene melts at around 79 °C, it ships and stores as a solid and may need gentle warming to handle in bulk. Second, its flash point near 74 °C means it is classified as a flammable solid - covered in the safety section below.

🏭 Where Durene Comes From

Historically, durene was isolated from the heavy-aromatic (C₁₀) fraction of coal tar, where it occurs naturally alongside its isomers. Coal-tar recovery alone, however, cannot keep pace with demand - a chronic shortfall the industry refers to as the "durene deficiency."

Modern production is therefore largely synthetic: lighter aromatics such as p-xylene or pseudocumene (1,2,4-trimethylbenzene) are methylated with methanol or methyl chloride over a shape-selective zeolite catalyst, favoring the durene isomer. The crude product is then separated and purified to the grade the end use requires. We break down both routes and their economics in How Durene Is Made: Coal Tar vs Methylation of Xylene.

⚗️ The Tetramethylbenzene Isomer Family

Benzene with four methyl groups can be arranged in three ways, and the difference matters enormously in practice:

Only the symmetrical 1,2,4,5 arrangement lets all four methyl groups be oxidized cleanly and evenly to a single anhydride, which is why durene - not its isomers - is the one that goes into PMDA. We cover the structural and separation details in Tetramethylbenzene Isomers: Durene vs Isodurene vs Prehnitene.

💡 The PMDA Value Chain - Why Durene Matters

The overwhelming majority of durene is consumed in one transformation: catalytic oxidation to pyromellitic dianhydride (PMDA). In the vapor-phase process, durene vapor and air pass over a vanadium/titanium oxide catalyst; the four methyl groups are oxidized and cyclized into two anhydride rings. PMDA is then the gateway to a family of high-performance materials.

Because durene sits right at the head of this chain, its purity directly determines the quality of everything downstream. The step-by-step chemistry, catalysts and yields are covered in From Durene to PMDA, and you can view our own PMDA product for the downstream material.

🧩 Major Applications of Durene

1. Polyimide films for electronics

Reacting PMDA with an aromatic diamine yields a polyamic acid that is cured (imidized) into polyimide - the amber, heat-resistant film best known under the Kapton™ trade name. Polyimide films are the backbone of flexible printed circuits, flexible displays, spacecraft and aircraft insulation, and increasingly the insulation systems inside electric-vehicle motors and batteries. This is the single largest demand driver behind durene. See Durene's Role in Polyimide Film Production.

2. Epoxy curing agents

As a symmetrical tetra-functional anhydride, PMDA is used as a high-temperature curing agent (hardener) and crosslinker for epoxy resins, giving thermosets with high glass-transition temperatures and excellent thermal and electrical performance - valued in electrical laminates, castings and encapsulants. More in Durene-Derived PMDA as an Epoxy Curing Agent.

3. High-temperature plasticizers

Esterifying PMDA with long-chain alcohols produces pyromellitate esters such as tetraoctyl pyromellitate (TOPM) - ultra-low-volatility plasticizers used where ordinary phthalates would evaporate, notably in high-temperature wire and cable insulation. Explore the chain in From Durene to High-Temperature Plasticizers.

4. Solvent, reagent & reference standard

Beyond the PMDA route, durene's symmetry and well-defined spectra make it a convenient reference standard and internal standard in NMR and GC, a probe molecule in matrix-isolation spectroscopy, and a substrate in organic synthesis. See Durene as a Research Reagent and Reference Standard.

🔍 Purity & Grades

Purity is not a cosmetic concern for durene. Isomeric and mono-functional impurities carried into the oxidation step generate mono-anhydride by-products that act as chain-terminators and can inhibit polyimide polymerization, degrading film quality. High-grade durene is typically produced by melt (static) crystallization, with zone refining available for the most demanding electronic and analytical uses. We explain grade selection in Durene Purification and Grades - and the exact grades we stock are on the product page.

⚖️ How Durene Compares

Durene is one member of a broader family of methylated benzenes, and choosing the right one comes down to the anhydride you need and the application:

🔹 Durene vs pseudocumene: pseudocumene (1,2,4-trimethylbenzene) oxidizes to trimellitic anhydride (TMA), a tri-functional anhydride, whereas durene gives the tetra-functional PMDA - different functionalities for different end uses. See Durene vs Pseudocumene.

🔹 Durene vs mesitylene & other polymethylbenzenes: where mesitylene (1,3,5-trimethylbenzene) is prized as a solvent and UV-cure intermediate, durene's niche is high-value anhydride production. Compared side by side in Durene vs Mesitylene and Other Polymethylbenzenes.

🦺 Safety at a Glance

Full handling, storage, transport and regulatory detail is in Durene Safety, Handling and Storage; the definitive SDS is on the product page.

📈 Market Outlook

Durene demand tracks the fortunes of PMDA and, ultimately, polyimide films. Growth in 5G infrastructure, foldable and flexible displays, flexible printed circuits, and electric-vehicle power electronics is steadily lifting demand for high-purity polyimide - and therefore for the durene at the base of that chain. China plays a central role in global supply of both durene and PMDA. We map the drivers and regional supply picture in Global Durene & PMDA Market Outlook.

📦 Sourcing Durene

When sourcing durene, the essentials are: the purity grade matched to your application (oxidation feedstock vs analytical reference behave very differently), temperature-appropriate packaging for a material that melts near 79 °C, and a supplier who can document consistency batch to batch. Our buyer's checklist is in Sourcing Durene: A B2B Buyer's Guide. For grades, lead time and a quotation, go straight to the Durene product page.

❓ Frequently Asked Questions

🔹 Is durene the same as durol?

Yes. Durene, durol and sym-tetramethylbenzene are all common names for the same compound, 1,2,4,5-tetramethylbenzene (CAS 95-93-2).

🔹 What is durene mainly used for?

Its dominant use is as the feedstock for pyromellitic dianhydride (PMDA), which in turn makes polyimide films, epoxy curing agents and high-temperature plasticizers. It is also used as a laboratory reference standard.

🔹 Is durene a solid or a liquid?

A solid at room temperature. It melts at around 79 °C, so bulk handling may involve gentle, controlled heating.

🔹 Why is durene described as "symmetrical"?

Its four methyl groups sit at the 1, 2, 4 and 5 positions, giving the molecule a center of symmetry with two equivalent open positions. This symmetry is what allows clean oxidation to PMDA.

🔹 Is durene hazardous?

It is a flammable solid (GHS H228) and very toxic to aquatic life with long-lasting effects (H410). It should be kept away from oxidizers and ignition sources and prevented from entering waterways.

🔹 Where can I buy durene?

Sinolook Chemical supplies durene to buyers in 50+ countries. Request grades and a quotation on the product page or via the contacts below.

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