In the master's thesis, we investigated the influence of the addition of various alcohols on the value of the maximum density and the temperature at which this maximum is reached for different aqueous alcohol mixtures at low temperatures (1–6 °C). We prepared mixtures of water and different alcohols (methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 2,2-dimethyl-1-propanol, 1-butanol, 2-butanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol and a series of pentanols) at various alcohol mole fractions (x) ranging from ~0.001 ≤ x up to the solubility limit of the alcohol in water. The density was measured using an Anton Paar DSA 5000 M densimeter, and by interpolating a quadratic function, we determined the temperature of maximum density (Tₘₐₓ) and the corresponding value of the maximum density (ρₘₐₓ). The mixtures were divided into three groups based on the length of the carbon chain (C₁–C₃, C₄, C₅). The results show that at low concentrations of methanol, ethanol, and propanols, there is a slight increase in Tₘₐₓ compared to pure water (ΔT > 0); however, as the alcohol mole fraction increases, Tₘₐₓ decreases. In alcohols with four and five carbon atoms, Tₘₐₓ decreases already with minimal alcohol additions (ΔT < 0). In all cases, ρₘₐₓ generally decreases with increasing alcohol content. This work contributes to the understanding of hydrogen bonding and Van der Waals interactions in aqueous alcohol mixtures and provides a foundation for the development of quantitative thermodynamic models.
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