Properties of Diphyl DT

General chemical and physical properties

Diphyl DT is a mixture of isomeric ditolyl ethers (dimethyl diphenyloxides) of low viscosity. It has a high boiling point between 284 and 294 °C at a pressure
of 1.013 bar.

Special mention should be made of the low viscosity of Diphyl DT even at low temperatures, which allows an application range from -30°C to +330°C.
 

The water content of Diphyl DT amounts to a maximum of 0.02% by weight on delivery. Diphyl DT is not hygroscopic and is virtually immiscible with water.
Even at 30°C and 100% relative humidity, a maximum of only 0.07 % by weight water dissolves in Diphyl DT.

Diphyl DT will not ignite spontaneously before reaching an autoignition temperature of above 545 °C. Diphyl DT thus belongs to Temperature Class T 1.

Unlike water, the conversion from a liquid to a solid state reduces the volume. Apparatus and pipelines can therefore never be damaged by solidification
of the Diphyl DT filling.

The typical inherent odour of Diphyl DT enables leaks to be identified quickly. The level of production‑related impurities, such as chlorine and sulphur compounds,
is so low in Diphyl DT that corrosive damage caused by the heat transfer fluid can be ruled out.

Spezifikation und Kennzahlen von Diphyl DT

Specification                                    Test method              Unit          Diphyl DT

Ditolyl ether content                                            gas chromatography           %                   min. 97.5

Water                                                                  K. Fischer (Coul.)                mg/kg             max. 200


Compliance with the Specification is subject to constant monitoring



Characteristic data

Density (20°C)                                                    DIN 51757                            kg/m³                    approx. 1035
                                                                            ASTM D 4052-91

Pourpoint                                                             DIN ISO 3016                       °C                  approx. -54

Kinematic viscosity (20 °C)                                 DIN 51561                            mm²/s            approx. 6.3
                                                                            ISO 3104/3105
                                                                            ASTM D 445/446

Neutralization number (acidic)                            DIN 51558 (part 1)               mg KOH/g      approx. 0.01
                                                                            ASTM D 974-64

Boiling temperature (1.013 bar)                          ISO 918-                              °C                  284 - 294
                                                                            OECD Test Spec. 103

Flash point                                                          EN 22719                             °C                  approx. 135
                                                                            ASTM D 93-75

Autoignition temperature                                     DIN 51794                            °C                  approx. 545
                                                                            ASTM D 286-58T

Lower explosion limit (132 °C)                            -                                           % by vol.       approx. 0.8

Upper explosion limit (206 °C)                             -                                           % by vol.       approx. 14.5

Solubility in water (20°C)                                    Quentin method                   mg/l                approx. 4

Surface tension (20°C)                                       OECD ring method               N/m                approx. 0.04

Thermal conductivity (20°C)                               -                                           W/m  ^. K         approx. 0.133

Mean specific heat (20°C)                                  -                                           kJ/kg  ^.K         approx. 1.58

Max. film temperature                                         -                                           °C                  approx. 340

Gross calorific value H_{0                                    -}                                             MJ/kg             approx. 39.1

Net calorific value H_{U                                        -}                                              MJ/kg             approx. 37.6

Ignition class                                                       VDE 0165                            -                     G1

Temperature class                                              VDE 0171                            -                     T1

Hazard class                                                      -                                           -                     None

Coefficient of thermal expansion (20 - 330°C)   -                                           K^-1                 10.6 ^. 10 ^-4


Characteristic data provide further information about the product
and are not subject to constant monitoring