Alternative solvents for a method of reclaiming styrene and other products from polystyrene based materials

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The inventors have discovered that d-limonene, or with 1limonene, in its racemic form, dipentene, are especially suitable alternative solvents for use in the present invention.
D-limonene, an oily solvent obtained by processing citrus peels, particularly orange peels, has a very low toxicity and has been used commercially for many years both as a solvent in various processes and as an orange flavoring agent in foods.
D-limonene is relatively expensive and slightly less effective than styrene oil as a solvent for polystyrene, but it will serve as an alternate solvent to the styrene oil solvent, and it is now governmentally approved for use in an occupied facility.
To clarify the following description, a short discussion of selected alternate solvents is useful.
D-limonene is a hydrocarbon compound in a class called monocyclic monoterpenes, which has unusual properties.
All monoterpenes, which have the formula C.
sub.
10 H.
sub.
16, are constructed of a "building block", C.
sub.
5 H.
sub.
8, which is also the formula of an independent hydrocarbon compound, isoprene.
Isoprene is widely used to make many petrochemical compounds, such as man-made "natural" rubber.
D-limonene is, in fact, a dimer of isoprene.
D-limonene is one of a pair of "twin" compounds called enantiomers.
Enantiomers are compounds having identical chemical formulas but chemical structures that are mirror images of each other.
D-limonene is the dextrorotatory twin (rotates plane-polarized light to the right), and l-limonene is the levorotatory twin (rotates plane-polarized light to the left).
Both of the limonenes occur in citrus peels, but d-limonene is much more prevalent.
If d-limonene and l-limonene are present in equal parts, the mixture is said to be racemic.
This racemic mixture is called dipentene.
D-limonene is prepared by crushing and then steam-distilling citrus peels.
The resulting distillate is actually mostly d-limonene, but it also contains a minor percentage of l-limonene (which is inseparable from d-limonene for practical purposes), and a very small amount of other impurities