A Unilamellar Crystalline Haze-Forming Phase of Methyl-Branched Isomerized High-Molecular-Weight Alkanes

A new phase of wax is reported, formed from long randomly methyl-branched alkyl-chain molecules with sufficiently long unbranched runs. These are unilamellar monomolecular thin crystalline sheets, which stack into layered structures but are not laterally correlated between layers and will swell in the presence of a solvent. The structures are related to crystalline lamellae in semicrystalline polymers. The molecules were formed by isomerization of the heavy fraction of n-alkanes derived from Fischer-Tropsch synthesis. This wax comes out of solution as a kinetically slow-forming haze at temperatures well above the cloud-point. X-ray, neutron, and light scattering studies, along with compositional analysis and calorimetry, characterized its properties. Solution theory using a variable pseudocomponent method was employed to explain its equilibrium and kinetic crystallization behavior. Observations of some other waxes that swell are also reported.