Dimethyl Terephthalate
The dimethyl ester of terephthalic acid supplied by Chelora Chemicals — the original industrial raw material for PET polyester and still used for polyester film and specialty resin grades — exported from Indonesia as white crystalline flake with full batch documentation on every shipment.
What Dimethyl Terephthalate is, and why buyers source it
A working overview of the compound's chemistry, its historical and continuing role in polyester manufacture, and the grade Chelora Chemicals keeps in regular supply.
Dimethyl Terephthalate is the dimethyl ester of terephthalic acid: the same symmetric, para-substituted benzene ring as purified terephthalic acid, but with each carboxylic acid group capped as a methyl ester rather than left free. That esterified form is considerably more soluble and easier to purify by distillation and crystallisation than the free diacid, which is precisely why DMT was the industry's original route to high-purity polyester feedstock, before terephthalic acid purification technology advanced enough to make the PTA route commercially dominant.
At room temperature it is a white, odourless crystalline solid or flake, melting to a clear liquid well above its melting point and only sparingly soluble in cold water, though it dissolves more readily in many organic solvents. It reacts with glycols by transesterification, releasing methanol rather than the water that the free diacid route releases.
Where it fits in the value chain
Dimethyl Terephthalate's defining end use is transesterification with monoethylene glycol to produce polyethylene terephthalate (PET), historically the dominant industrial route to PET and still used today for certain film grades (including high-clarity polyester film) and in regions and plants built around DMT-based infrastructure. It is also transesterified with 1,4-butanediol to give polybutylene terephthalate (PBT) engineering resin, and with other polyols in specialty polyester and alkyd resin formulations where its high purity and ease of handling as a melt or solid are valued.
Grade we supply
Chelora Chemicals offers Dimethyl Terephthalate in fibre/film grade (99.9%+ purity) as crystalline flake, suited to transesterification for PET film and fibre, PBT manufacture, and specialty polyester resin production. The grade is supplied with a batch-wise certificate of analysis.
How Dimethyl Terephthalate is made
An overview of the production route for orientation purposes. Our manufacturing partners' own process parameters and in-process controls are proprietary and are not disclosed beyond what is needed to interpret the certificate of analysis.
Dimethyl Terephthalate is manufactured by the combined oxidation and esterification of para-xylene with methanol, in what is widely known as the Witten process. Para-xylene is oxidised with air, and the resulting intermediate acids and partial esters are esterified with methanol as the sequence proceeds, passing through methyl p-toluate as a key intermediate, until both ring substituents have been fully oxidised and esterified to give dimethyl terephthalate directly, without isolating the free diacid at any stage.
The crude DMT is purified by fractional distillation and recrystallisation, which is comparatively straightforward given the ester's higher solubility in organic solvents and its clean, sharp melting point relative to the free diacid, and is what originally made the DMT route commercially attractive before PTA purification technology (notably catalytic hydrogenation of the 4-CBA impurity) matured enough to allow the simpler, more direct PTA process to take over as the industry's dominant route.
Industries and processes that use it
Dimethyl Terephthalate is consumed across PET film and fibre manufacture, PBT engineering resin, and specialty polyester and alkyd resin formulations. The fields below account for most of the demand we see through our export desk.
PET Film Manufacture
Transesterified with monoethylene glycol to produce high-clarity PET film, including biaxially oriented film used in packaging, electrical insulation and imaging media.
PET Fibre (DMT Route)
Transesterified to produce PET resin for textile fibre manufacture in plants built around DMT-based process infrastructure.
Polybutylene Terephthalate (PBT)
Transesterified with 1,4-butanediol to give PBT, an engineering thermoplastic used in electrical connectors and automotive components.
Specialty Polyester & Alkyd Resins
Transesterified with other polyols in specialty polyester coil-coating resins and alkyd resin formulations that value its high purity and ease of handling.
How the molecule is typically carried forward
The two methyl ester groups on the symmetric aromatic ring govern almost all of this molecule's further reaction chemistry. Reaction classes below account for most of the ways Dimethyl Terephthalate is converted into a finished polyester.
Transesterification
Each methyl ester reacts with a glycol hydroxyl under catalysis, releasing methanol, to form a new glycol ester linkage — the defining first step of DMT-route polyester manufacture.
Polycondensation
The resulting bis(glycol ester) is further polymerised under vacuum and heat, releasing excess glycol and building the long PET or PBT polymer chain.
Methanol Recovery & Recycle
The methanol released during transesterification is recovered by distillation and recycled, both as a process economy and because residual methanol must be removed before polycondensation proceeds.
Alkyd Resin Incorporation
Reaction with polyol and fatty-acid components under esterification conditions incorporates the terephthalate unit into alkyd coating-resin formulations.
Dimethyl Terephthalate against other polyester intermediates we supply
Buyers sourcing DMT for polyester manufacture often also consider the now-dominant PTA direct-esterification route, or the nylon-chain intermediates for comparison. A quick reference to what else is on our regular supply list.
| Product | CAS Number | Category | Notes |
|---|---|---|---|
| Dimethyl Terephthalate | 120-61-6 | Aromatic diester | The product on this page — the original ester-route raw material for PET and PBT. |
| Purified Terephthalic Acid | 100-21-0 | Aromatic dicarboxylic acid | The now-dominant direct-esterification alternative raw material for PET — see its product page. |
| Adipic Acid | 124-04-9 | Aliphatic dicarboxylic acid | A related dicarboxylic acid, the co-monomer of nylon 66 — see its product page. |
| Caprolactam | 105-60-2 | Cyclic lactam | The single-monomer feedstock for nylon 6, a related condensation-polymer chain — see its product page. |
Exact physical constants and purity specifications are confirmed per batch on the certificate of analysis — treat the notes above as a sourcing guide, not a specification sheet, for products other than Dimethyl Terephthalate.
Safety classification at a glance
Based on GHS classification as commonly listed for this substance. This is a summary for orientation only — always work from the current safety data sheet supplied with your specific batch.
Causes serious eye irritation.
Causes skin irritation.
Comparatively low acute oral and dermal toxicity relative to many industrial organic esters.
Handled as crystalline flake; minimise airborne dust during transfer and packing.
Chemical-resistant gloves and safety goggles are the baseline for routine handling.
Handled molten above its melting point in some dosing systems; standard hot-material handling precautions apply.
Combustible as a fine dust under specific conditions; avoid dust accumulation and ignition sources.
Warning — GHS07 harmful pictogram applies.
This compound causes skin and eye irritation and has a comparatively low acute toxicity profile among industrial esters. It should be handled with chemical-resistant gloves, eye protection and dust control during milling and packing, and with standard hot-material precautions where handled molten. Full first-aid, storage, spill and PPE guidance is in the MSDS issued with every shipment, and should be read in full before this material is handled.
Keeping it on spec between delivery and use
General storage guidance for this grade. Site-specific storage rules, segregation requirements and re-test intervals should follow your own EHS procedures and the MSDS issued with your batch.
Store in a cool, dry area away from strong oxidising agents, in tightly closed original packaging, protected from moisture. If handled molten, maintain even heating to avoid localised degradation and colour development. Re-check assay, colour and melting point on a batch held past its retest date before use.
How it ships from Indonesia
Standard packing and export terms for this product. Confirm exact figures against your order — they vary slightly by destination and quantity.
What travels with every batch
Specification is agreed before the purchase order, not discovered on arrival. Every shipment of Dimethyl Terephthalate leaves with a documented, checkable paper trail.
Certificate of Analysis
Batch-wise assay, colour and key physical constants, issued against the agreed specification so your QC team can check it, not just file it.
Safety Data Sheet
GHS-format SDS in English covering hazard classification, handling, storage, first-aid and spill response for the exact grade shipped.
Technical Data Sheet
Reference physical and chemical properties, recommended storage and typical applications, for internal circulation to your process or R&D teams.
Certificate of Origin
Confirms Indonesian origin for customs clearance and any preferential-duty claim at your destination port.
Dangerous Goods Declaration
UN packing group, classification and shipper's declaration prepared ahead of loading so documentation never holds up customs.
Third-Party Inspection
Independent pre-shipment inspection and re-sampling can be arranged on request, at your cost, for buyers who require it as a matter of policy.
Frequently asked questions
What buyers most often ask our sales desk about this grade.
01What is Dimethyl Terephthalate used for?+
02What is the CAS number of Dimethyl Terephthalate?+
03How is Dimethyl Terephthalate made?+
04What purity grade does Chelora Chemicals supply?+
05Is Dimethyl Terephthalate hazardous?+
06Why was DMT the original industrial route to PET before PTA became dominant?+
07What packing options are available?+
08How long does delivery take?+
09Can I get a sample before placing a bulk order?+
10Do you supply the direct-esterification alternative as well?+
Need Dimethyl Terephthalate on spec, on time?
Send us your required purity, quantity, packing preference and destination port. Our desk quotes most enquiries within one working day.