Direct emissions of nonmethane hydrocarbons, monocarboxylic acids, and low molecular weight carbonyl
compounds were measured from vegetation typical to
central New Mexico. These species included quaking aspen,
cottonwood, Gambel oak, Douglas fir, Engelmann spruce,
Rocky Mountain juniper, pinyon pine, and ponderosa pine.
The hydrocarbon emissions from most of the coniferous
trees were dominated by α-pinene. In general, α-pinene
emissions were 100−10 000 ng g-1 h-1 and displayed the
expected temperature dependence. Other identified
hydrocarbons included isoprene, camphene, β-pinene,
myrcene, Δ3-carene, and d-limonene. The deciduous trees
as well as the spruce and fir trees showed isoprene
emission rates of 100−100 000 ng g-1 h-1. Formaldehyde
and acetaldehyde were the most common low molecular
weight carbonyl compounds measured. The carbonyl
emissions averaged 50−1660 ng g-1 h-1, depending on
the compound and the trees species. Unlike the hydrocarbons,
the carbonyl emissions displayed little correlation with
enclosure temperature. Formic acid emissions averaged 15−920 ng g-1 h-1, and acetic acid emissions averaged 50−1300 ng g-1 h-1. As with the carbonyls, poor correlation was
found between the acid emissions and the enclosure
temperature. The deciduous trees were found to have
average (mass-based) emissions of 98% hydrocarbons, 1%
carbonyls, and 1% organic acids. The coniferous trees
averaged 80%, 8%, and 12%, respectively.
A convenient and general method was established to append tri-, hexa-, and nonadentate ligands about an aromatic or aliphatic core. This approach allows a variety of commercially available carboxylic acids to be transformed to their N-tris(hydroxymethyl)methylcarboxamides in one step. The selective activation of the acid functionality to form the polyhydroxylated dendritic cores has been achieved using the acyl transfer agent N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ).
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