Therminol® VP1 Heat Transfer Fluid


Therminol VP-1 heat transfer fluid is an ultra-high temperature synthetic heat transfer fluid designed to meet the demanding requirements of vapor phase systems or liquid phase systems.

Performance Benefits

  • Superb Heat Transfer Properties—Therminol VP-1 is a synthetic heat transfer fluid which combines exceptional thermal stability and low viscosity for effective, dependable, uniform performance in a wide optimum use range of 12° to 400°C (54° to 750°F ). Therminol VP-1 has the highest thermal stability of all organic heat transfer fluids.
  • Low Viscosity—Therminol VP-1 has a low viscosity to 12°C (54°F) because of its crystallization point of 12°C (54°F), this fluid may need tracing in colder climates to prevent operational problems.
  • Vapor Phase Heat Transfer Fluid—Therminol VP-1 is an eutectic mixture of diphenyl oxide (DPO) and biphenyl. It can be used as a liquid heat transfer fluid or as a boiling-condensing heat transfer medium up to its maximum use temperature. It is miscible and interchangeable (for top-up or design purposes) with other similarly constituted diphenyl-oxide (DPO)/biphenyl fluids.
  • Precise Temperature Control—Able to operate as a vapor-phase heat transfer fluid, thus Therminol VP-1 is excellent for use in heat transfer fluid systems requiring very precise temperature control.

Typical Properties

PropertyTest MethodTypical Value, Units
AppearanceClear, water white liquid
Composition Biphenyl/diphenyl oxide (DPO) eutectic mixture
Maximum bulk temperature400 °C (750 °F)
Maximum Film Temperature430 ºC (800 ºF)
Normal Boiling Point257 °C (495 °F)
Flash Point


124 °C (255 °F)
110 °C (230 °F)
Crystallization Point12 °C (54 °F)
Autoignition TemperatureASTM E659
DIN 51794
601 ºC (1114 ºF)
621 ºC (1150 ºF)
Coefficient of thermal expansion @ 200°C
0.000979 /°C (0.000544 /°F)
Liquid Density
@ 15ºC
@ 25ºC
ASTM D 4052
ASTM D 4052

1068 kg/m3 (8.91 lb/gal)
1060 kg/m3 (8.85 lb/gal)
AcidityASTM D 664<0.2 mg KOH/g
Molecular Weight (Average)166
Pseudocritical temperature499 °C (930 °F)
Pseudocritical pressure33.1 bar (480 psia)
Pseudocritical density327 kg/m3 (20.4 lb/ft3)
Sulfur ContentASTM D-7691<10 ppm
Copper CorrosionASTM D 130<<1a
Moisture Content, maximumASTM E-203300 ppm
Volume contraction upon freezing6.27 %
Volume expansion upon melting6.69 %
Dielectric Constant @ 23°CASTM D-9243.35
Surface Tensionb  @ 25°C36.6 dynes/cm
Properties reported here are typical of average lots.

Key Attributes

  • Low Viscosity
  • Accurate Temperature Control
  • Superb Heat Transfer Properties
  • Vapor Phase Heat Transfer Fluid


  • htf – fine chemicals
  • htf – production of bioalcohol
  • htf – production of biodiesel
  • Adhesives
  • Calendar roll heating
  • Chemicals & petrochemicals
  • Distillation
  • Extruding
  • Fatty acid
  • Fibers
  • Formaldehyde
  • Gas to liquid (gtl)
  • Gas treatment / sweetening / desulpheriz
  • Lube oil refining
  • Methyl methyl acrylate (mma)
  • Polyester (pet)
  • Refining
  • Resins
  • Solar csp
  • Specialty and batch chemical production
  • Specialty chemicals
  • Styrene
  • Tall oil
  • Terephthalic acid (pta)
  • Waste heat recover + orc

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