The polymorphism of 1-heptadecanol (C 17 H 35 OH), 1-octadecanol (C 18 H 37 OH), 1-nonadecanol (C 19 H 39 OH), and 1-eicosanol (C 20 H 41 OH) has been studied by X-ray powder diffraction, differential scanning calorimetry (DSC), Raman scattering, and infrared spectroscopy (IR). At room-temperature two monoclinic forms, and γ, are observed. For the n-alkanols with an even number of carbons the stable form is γ, whereas is the stable form for the n-alkanols with an odd number of carbons. On heating, these phases transform to a monoclinic, rotator form R' IV at a few degrees below the melting point. A metastable form is obtained by quenching from the melt for 1-octadecanol and 1-eicosanol, which is isostructural with the -phase of the odd alkanols. Cell parameters, temperatures, and enthalpies of the transitions are reported.

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The experimental temperature−composition phase diagram of the binary system between hexadecane (C16H34) and 1-hexadecanol (C16H33OH) has been established by combining thermal analysis and powder X-ray diffraction (XRD). Beforehand, crystal structures of the solid ordered phases of the components involved were determined from XRD data. Hexadecane displays a triclinic form Tp belonging to the space group P1̄, with Z = 1. The unit cell dimensions are a = 4.269 Å, b = 4.811 Å, c = 22.34 Å, α = 84.54°, β = 67.43°, and γ = 73.00°. 1-Hexadecanol displays a monoclinic form γ belonging to the space group A2/a with Z = 8. The unit cell dimensions are a = 8.980 Å, b = 4.939 Å, c = 87.91 Å, and β = 122.63°. The phase diagram between both components is characterized by two invariants, a eutectic (located at T = 289.5 K) and a metatectic (located at T = 318.8 K). The miscibility in the solid state is very restricted, limited to the regions rich in C16H34 and C16H33OH. Resulting alloys have led to the design of a double-wall glass for the thermal protection of liquid products between 13 and 18 °C, effective for 4.5 h in an external environmental temperature of 24 °C.