Density and viscosity measurements of (piperazine + water) and (piperazine + 2-dimethylaminoethanol + water) at high pressures

The purpose of this paper is broadening the understanding of amine solution behaviour through the experimental measurements of density (up to 140 MPa) and viscosity (up to 100 MPa) in a temperature range from (293.15 to 393.15) K. The two selected blends are Piperazine (PZ) + Water (10% amine weight concentration) and Piperazine (PZ) + 2-Dimethylaminoethanol (DMAE) + Water (10% and 30% amine weight concentration, respectively). Densities were measured using a vibrating tube densimeter (Anton Paar DMA HPM) with an expanded uncertainty (k = 2) less than 0.7 kg·m−3. Viscosities were obtained using a falling body viscometer which was calibrated with water and dodecane. The viscosity expanded uncertainty (k = 2) ranges from 2.5% for the highest viscosity to 3.2% for the lowest one. Experimental data were fitted to modified Tammann-Tait equation for densities and modified VFT model for viscosities, obtaining good results for both equations.