The vapor pressure of pure and aqueous glutaraldehyde

A recirculating equilibrium still was used to measure pressure–temperature–liquid composition–vapor composition (PTxy) data on 18 dilute mixtures of water(1) + glutaraldehyde(2) between 38° and 85°C. The Henryʹs constants, H2,1 (kPa/mole fraction), derived from the PTxy data, were fitted by least-squares to give the equation, ln H2,1=29.1352−9187.99/T(K). To facilitate calculation of glutaraldehyde exposure during typical use, the Henryʹs constant correlation was used to compute concentrations of glutaraldehyde in air saturated by aqueous glutaraldehyde solutions. Vapor-pressure data for a dried sample of pure glutaraldehyde were measured in an ebulliometer between 55° and 163°C. An Antoine equation fitted to the intermediate temperature data between 74° and 109°C gives a normal boiling point for glutaraldehyde of 189.4°C and a 20°C vapor pressure of 0.044 kPa. The log vapor pressure vs. 1/T(K) curve shows downward curvature at both the high-temperature and low-temperature ends. This suggests (i) a strong hydrogen-bonding effect at low temperatures and (ii) the possibility of polymerization of the sample at high temperatures. Finally, PTx data were measured in an ebulliometer for four aqueous mixtures between 10 and 50 mass % glutaraldehyde. Henryʹs constants derived from infinite-dilution activity coefficients from a Barkerʹs method fit to the PTx data agree with the Henryʹs constants from the PTxy data.