Pinenes


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Pinenes

 

bicyclic terpenes, C10H16; colorless liquids with the odor of pine cones. Freely soluble in nonpolar organic solvents, insoluble in water, and readily oxidizable upon exposure to air, especially in light. Of the three known α-, β-, and δ-isomers, only α-pinene and β-pinene, or nopinene, are widespread in nature (respective boiling points, 155.9° and 166°C; densities, 0.858 and 0.871 g/cm3 at 20°C). Both α- and β-pinenes occur in various turpentines, from which they are extracted by rectification, and in many essential oils.

Pinenes are extremely reactive. Upon heating to temperatures above 300°C, α -pinene isomerizes to allo-ocimene, and β-pinene to myrcene; pinenes polymerize readily under the action of acids. Pinenes are used as solvents for varnishes and paints and as raw material in the manufacture of camphor, terpineol, terpin hydrate, insecticides, and odoriferous substances.

References in periodicals archive ?
Figure 5 shows the relative effects of press variables on the pinene emissions.
Emissions of formaldehyde, HMw- VOC, and pinenes on a per unit panel weight basis were lower for the larger panels than the smaller panels for all resin types.
In most cases, within panels hot-pressed using the same resin, panels pressed at the lower temperature, longer pressing time condition emitted less formaldehyde, pinenes, and HMwVOCs than panels hot-pressed at the higher temperature for shorter times.
For all three resins, the emissions of formaldehyde, HMwVOC, and pinenes decreased when the panel edge size was doubled.
The HMwVOC and pinene emissions were lower with the lower temperature and longer pressing time, although the change in the HMwVOC emissions was not statistically significant due to variation in the data.
For pMDI-bonded particleboard, the formaldehyde, HMwVOC, and pinene emissions were greater at a higher pressing temperature and lower pressing time compared to a lower pressing temperature and longer pressing time (Fig.