Bitumen asphaltenes

Bitumen asphaltenes undergo a variety of simple chemical conversions. For example, asphaltenes can be oxidized, sulfonated, sulfomethylated, halogenated, and phosphoryl-ated. The net result is the introduction of functional entities into the asphaltene structure which confer interesting properties on the products for which a variety of uses are proposed. 

The classic definition of asphaltenes is based on the solution properties of petroleum residuum in various solvents. This generalized concept has been extended to fractions derived from other carbonaceous sources, such as coal and oil shale. With this extension there has been much effort to define asphaltenes in terms of chemical structure and elemental analysis as well as by the carbonaceous source. This effort is summarized by Speight and Moschope-dis (i) in their chapter in this volume along with a good summary of the current thinking. Thus, there are petroleum asphaltenes, coal tar asphaltenes, shale oil asphaltenes, tar sands bitumen asphaltenes, and so on. In this chapter I will attempt to show how these materials are special cases of an overall concept based directly on the physical chemistry of solutions and that the idea that they have a specific chemical composition and molecular weight is incorrect even for different crude oil sources. 

Characteristics of Tar Sand Bitumen Asphaltenes as Studied by Conversion of Bitumen by Hydropyrolysis... 

Product Properties Maltene Virgin Bitumen Asphaltene- Enhanced Bitumen... 

The structure and chemistry of tar sand bitumen asphaltenes were studied indirectly by inference from processing and characterization of virgin bitumen and deasphaltened bitumen (maltenes). Results differ significantly from those derived from characterization of asphaltenes as isolated... 

Lanthanide shift reagents have been used to analyze structural aspects of bitumen asphaltene samples" . Addition of Yb(fod)3 shifted the resonances of hydrogen atoms a to oxygen atoms away from those a to aromatic rings, and enabled a bulk assessment of the concentrations of the two types of functionalities. 

Vanadium in Tar Sands, Bitumen, Asphaltenes, and Crude Oils... 

Isolation of Asphaltene. Asphaltenes were isolated by pre-ciptating with a 20-fold volume of n-pentane. The oil/resin fraction was separated from the preciptate by filtration through the thimble followed by Soxhlet extraction with n-pentane. The asphaltene fraction was obtained by Soxhlet extraction of the residue with benzene. In the following text, the three asphaltenes will be abbreviated as Bitu, R425 an< Rsoo rePresenti-nS bitumen asphaltene and asphaltenes derived from shale oils retorted at 425 and 500°C respectively. 

Experience has shown that crudes from adjacent wells can be different in composition. The siuface, physical, and chemical properties of associated emulsions can be expected to be as diverse and complex as the soiuce crudes and water. The variances in the elemental C, H, and N composition of components such as asphaltenes of crudes from various geologic origins as compiled (10, 12) show no apparent pattern emerging from the data as was the case with coal (5, 7). Sharma et al. (13) have shown the use of bitumen asphaltenes as thermal maturation indicators. 

Kjeldahl flask Bitterkeit bitterness Bittermandeldl bitter almond oil Bitterstoffe bitters Bitumen (Asphalten) bitumen (asphaltene) bivalent bivalent blahen bloat... 

Bitumen (Asphalten) bituminous coal/soft coal Steinkohle, bitumindse Kohle bivalence/divalence chem Zweiwertigkeit bivalent/divalent zweiwertig, bivalent, divalent black Rufi... 

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