Extracting diamonds from black gold

Diamond-like molecules have finally been obtained from petroleum by researchers at the Energy Research and Technology division of Chevron Texaco in Richmond, CA.

The shape and function of the large carbon molecules, known as diamondoids, will allow them to be used in a range of industries including microelectronics and pharmaceuticals.

Diamondoids are diamond molecules with the same internal structure as diamonds. The simplest diamondoid, the tricyclic molecule adamantane, was isolated from petroleum in the 1930s and synthesized half a century ago. Di- and triamantanes have also been made in the lab, but most of the larger and more structurally complex members of this class have not been available either synthetically or from natural sources, until now, according to a report in Chemical and Engineering News.

Higher diamondoids begin with tetramantane, which has four crystal cages of a diamond lattice. The ChevronTexaco researchers produced higher diamondoids up to undecamantane (11 crystal cages), which is a diamond with a weight of less than a billionth of a billionth of a carat.

The Chevron Texaco team, led by Dr. Robert Carlson, has developed a three-stage filtration process to obtain the diamondoids from petroleum. First, the petroleum is vacuum distilled leaving behind a residue oil that contains high levels of diamondoid molecules. Next, the oil is heated to further isolate the molecules. Finally, liquid chromatography is used to separate out the diamondoids. This also helps purify the large carbon molecules by evaporating other compounds. The diamondoids crystallise when the solution dries out at which point they can be collected.

Reflecting the commercial potential of the technology, ChevronTexaco Technology Ventures has formed MolecularDiamond Technologies, a new business unit, which will make small quantities of proprietary higher diamondoid materials commercially available for research and development in mid-year 2003.

MolecularDiamond Technologies will be located in Richmond, CA and will be headed by Dr. Waqar Qureshi, whose previous experience includes research and development, technology marketing, and venture capital investing.

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