Measurement of the critical parameters and vapor pressure for 3,3,3-trifluoropropyne

3,3,3-trifluoropropyne (TFPY) shows great promise as a new refrigerant due to its low global warming potential (GWP), zero ozone depletion potential (ODP) and resistance to decomposition into trifluoroacetic acid (TFA), thereby avoiding the environmental risks associated with current fourth-generation hydrofluoroolefins (HFOs). Herein, the critical parameters, and vapor pressure of TFPY were evaluated using the meniscus appearance method. Critical opalescence was observed within 243–373 K at intervals of 0.01 K, enabling precise identification of gas-liquid phase transition points. A total of 54 vapor pressure data points were collected and correlated using the Wagner equation. The critical temperature and vapor pressure of TFPY were determined to be 346.59 ± 0.50 K and 3.314 ± 0.113 MPa, respectively. Saturated vapor pressures of TFPY were measured from 243 K up to the critical temperature via the static method. The experimental data agree well with values predicted by the Wagner equation, with relative deviations ranging from −1.39% to 0.90%. The evaporation enthalpy of TFPY at various temperatures was determined by applying the Clapeyron and Wagner equations. The findings provide important thermophysical data to support TFPY applications and may also promote the development of other environmentally friendly fluoroalkyne-based alternatives in the industry.