DOTP - Dioctyl Terephthalate

About This Product

DOTP, dioctyl terephthalate or bis(2-ethylhexyl) terephthalate (CAS 6422-86-2, formula C24H38O4), is a general-purpose plasticiser for PVC. It is the ester of terephthalic acid and 2-ethylhexanol, made by direct esterification or by transesterifying dimethyl terephthalate. It is a clear, practically colourless, oily liquid with low volatility and a high flash point. Also sold as DEHT, it shares an empirical formula with DEHP, the ortho-phthalate often traded as DOP, but the ester groups sit on opposite sides of the benzene ring rather than next to each other. That structural difference is what matters commercially. DOTP is not an ortho-phthalate, so it falls outside the restrictions and authorisation requirements that EU REACH and UK REACH apply to several ortho-phthalates, and it has become the main replacement for DEHP in flexible PVC. It plasticises slightly less efficiently than DEHP, so formulators typically use a little more for the same hardness, but it offers lower volatility, better low-temperature flexibility and good electrical properties. Main applications include wire and cable insulation and sheathing, where low volatility and volume resistivity matter; flooring and wall coverings; calendered film and sheet; synthetic leather and coated fabrics; hoses and profiles; plastisols for coatings and moulding; and toys and childcare articles, where ortho-phthalate restrictions apply. It is also used in some adhesives, sealants and coatings as a non-reactive plasticiser. The parameters buyers agree are ester content, colour on the Pt-Co scale, acid value, water content, density at 20 °C and flash point. Cable grades often add a volume resistivity limit, and film grades may add heat-loss or volatility tests. Specify the tests you need and check each batch certificate of analysis against the agreed limits. DOTP is generally not classified as hazardous under CLP and is not regulated as dangerous goods for transport, but check sections 2 and 14 of the safety data sheet for the material offered. It is a registered substance under EU REACH; an importer into the EU or Great Britain should confirm which registration covers the import and use and ask for the current Candidate List statement. For food-contact or toy applications, request a declaration of compliance against the rules that apply to the finished article. Store DOTP in closed drums, IBCs or tanks in a dry area away from strong oxidisers. It is stable in normal storage, though heating in the presence of air can raise colour and acidity over time. Use mild steel or stainless steel tanks, and avoid long contact with some rubbers and plastics that it can swell. When you enquire, state the application, the grade (general or cable), limits for ester content, colour and acid value, any resistivity or volatility test, pack size (drum, IBC, flexitank or ISO tank), annual volume and destination.