Separation into fractions

fractions of a chromatographic column separation

Bitumen can be separated into fractions with same physical and chemical behavior. The first separation is by distinguish soluble and insoluble parts. The solvent is often n-heptane but other solvents are also used, which lead to other results. The soluble part is called maltenes and the insoluble is called asphaltenes. Maltenes can be further separated into 3 fractions with a chromatographic column. The separation is based on adsorption to the stationary phase and redissolve potential of the mobile phase.
The cut points between the fractions is optical and done manually, even coupling with spectral devices is possible.

asphaltenes

Introduction

I only investigated the residue of the vacuum distillation from crude oil (petroleum) and thus the term bitumen refers only to the origin from crude oil. When I refer to other origin for bitumen-like deposits, like natural asphalts, rock asphalts and oil sands, it will be noted.

The European usage of the term bitumen, or asphaltic bitumen is used. Synonyms in North America are asphalt or asphalt cement, but the term asphalt is used to describe the mixture of bitumen and mineral compounds.

bitumen surface