Apiezon AP201 Vapor Booster Fluid

Apiezon® AP201 is a vapor booster fluid designed to give longer oil service life and reduce the frequency of oil changes and cleaning time, thus cutting equipment downtime and service costs. It is highly resistant to oxidation and contains minimal volatile components.

Superior stability

Apiezon AP201 vapor booster fluid is specifically formulated to resist attack from air in gases being pumped and to be thermally stable at temperatures encountered in booster pump boilers. In addition, AP201 is highly resistant to traces of moisture in the gases being pumped.

Medium vacuum range

The vapor pressure characteristics of AP201 ensure that an ultimate pump pressure below 10-5 torr is obtainable and that the high boiler pressures necessary to generate the very powerful vapor jets in booster pumps can be achieved without excessive boiler temperatures.

Low viscosity

Apiezon AP201 has a low viscosity. This ensures that it is easily drained from systems at service time, thus reducing contamination from old oil remaining in the pump while also reducing pump draining and filling times.

Pump performance

Vapor booster pumps are used in industrial vacuum processes that require high volumes of gas throughput.

Longer service life

As a result of technological advantages inherent in the oil, AP201 has a typical service life much longer than that of less expensive, lower quality oils. This is illustrated by a “ruggedness test” in which oil in a diffusion pump is subjected to repeated cycles of 10 minutes of normal operation followed by a 5 minute period with the boiler heated off and the pump open to the atmosphere.

The oil and the jets are examined frequently, and the performance of the pump monitored. Cheaper oils rapidly deteriorate, showing an increase in viscosity and darkening in color. After 200 cycles, the pump jets and body are covered with a tarry black deposit. After 500 cycles, the deposits are so heavy that the pump fails to operate.

With AP201, the pump continues to operate efficiently for over 1000 cycles; throughout the test, the oil remains clear. The pump jets and baffles remain free from tarry deposits, thus ensuring easier and quicker pump cleaning and servicing.

Cost effective

The superior quality of AP201 gives you longer oil service life and reduces the frequency of oil changes, therefore reducing equipment downtime and service costs.

Apiezon® is a registered trademark of M&I Materials.


  • Oxidation resistance
  • Thermal stability
  • Moisture resistance
  • Low viscosity
  • Rapid pumpdown
  • Excellent vapor pressure



  • Vacuum metallurgy
  • Vacuum distillation
  • Vacuum metallization
  • Vacuum impregnation



SpecificationsAP201
Vapor pressure at 20ºC (torr)4x10-6
Specific gravity at 20ºC0.885
Viscosity at 20ºC (cSt )76
Viscosity at 40ºC (cSt )22
Flash point (ºC)196
Fire point (ºC)>200
Pour point (ºC)-30
Boiling point at 1 torr (ºC)165
Autoignition point (ºC)>320

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