Technical Data Sheet

Therminol® 66 Heat Transfer Fluid

Applications Key Attributes

htf - aluminum foil printing Experience
htf - bakery Fouling Resistant
htf - detergent Proven Fluid
htf - fine chemicals True 650° F (345° C) Performance
htf - food/feed/beverage processing
htf - production of bioalcohol
htf - production of biodiesel
Abs
Adhesives
Biomass - orc
Cement - waste heat recovery + orc
Chemicals & petrochemicals
Desalination
Fibers
Glass - waste heat recovery + orc
Hybrid solar + orc
Oil or gas processing
Oil recycling
Polyester (pet)
Polyethylene
Polymer & plastic
Polypropylene
Refining
Resins
Silicone
Solar csp
Specialty chemicals
Styrene
Tall oil

Product Description
Therminol 66 is the world’s most popular high-temperature, liquid-phase heat transfer fluid. Therminol 66 is
pumpable at low temperatures, and offers high temperature thermal stability.

Performance Benefits

Experience—Therminol 66 is the most popular high-temperature, liquid-phase heat transfer fluid in the
world. No heat transfer fluid material in the world has a higher degree of customer satisfaction than
Therminol 66.
Proven Fluid—In a wide variety of applications and thousands of systems around the world, Therminol 66
delivers excellent performance.
True 650° F (345° C) Performance—Therminol 66 sets the performance standard for high-temperature,
liquid-phase fluids. Users can expect many years of reliable, trouble-free operation even when operating
continuously at the recommended bulk temperature.
Fouling Resistant—Therminol 66 is specifically engineered to resist solids formation and system fouling,
providing more reliable operation and potential cost savings.

For more information, visit www.Therminol.com .

Typical Properties

Property Test Method Typical Value, Units

General
 Appearance Clear, pale yellow liquid
Composition Modified terphenyl
Recommended Bulk Temperature 345 °C (650 °F)
Maximum film temperature 375 °C (705 °F)
Normal Boiling Point 359 °C (678 °F)
Pumpability
@300 mm2/s (cSt) 11 °C (52 °F)
@ 2000 mm2/s (cSt) -3 °C (27 °F)
Flash Point
COC ASTM D92 184 °C (363 °F)
PMCC ASTM D93 170 °C (338 °F)
Autoignition Temperature ASTM E659 374 °C (705 °F)
DIN 51794 399 °C (750 °F)
Pour Point ISO 3016 -32 °C (-25 °F)
Minimum liquid temperatures for fully developed turbulent flow (NRe >
10000)
10 ft/s, 1-in. tube (3.048 m/s, 72 °C (162 °F)
2.54-cm tube)
20 ft/s, 1-in. tube (6.096 m/s, 53 °C (128 °F)
2.54-cm tube)
Minimum liquid temperatures for transitional region flow, (NRe > 2000)
10 ft/s, 1-in. tube (3.048 m/s, 35 °C (96 °F)
2.54-cm tube)
20 ft/s, 1-in. tube (6.096 m/s, 26 °C (78 °F)
2.54-cm tube)
Coefficient of thermal expansion
@ 200°C 0.000819 /°C (0.000455 /°F)
Viscosity, Kinematic
@ 100°C ASTM D 445 3.80 cSt, mm2/s
@ 40°C ASTM D 445 29.6 cSt, mm2/s
Liquid Density
@ 15°C ASTM D 4052 1012 kg/m3 (8.44 lb/gal)
@ 25°C ASTM D 4052 1005 kg/m3 (8.4 lb/gal)
Acidity ASTM D 664 <0.2 mg KOH/g
Molecular Weight (Average) 252
Pseudocritical temperature 569 °C (1056 °F)
Pseudocritical pressure 24.3 bar (353 psia)
Pseudocritical density 317 kg/m3 (19.8 lb/ft3)
Copper Corrosion ASTM D 130 <<1a
Moisture Content, maximum ASTM E-203 150 ppm
Dielectric Constant
@ 23°C ASTM D-924 2.61

Comments
Properties reported here are typical of average lots. Eastman makes no representation that the material in any
particular shipment will conform exactly to the values given.

Eastman and its marketing affiliates shall not be responsible for the use of this information, or of any product, method, or apparatus mentioned, and
you must make your own determination of its suitability and completeness for your own use, for the protection of the environment, and for the health
and safety of your employees and purchasers of your products. No warranty is made of the merchantability of fitness of any product, and nothing
herein waives any of the Seller's conditions of sale.

1/7/2021 11:03:53 AM
© 2021 Eastman Chemical Company or its subsidiaries. All rights reserved. As used herein, ® denotes registered trademark status in the U.S.
only.