Orange oil

Orange oil is an essential oil produced by cells within the rind of an orange fruit (Citrus sinensis fruit). In contrast to most essential oils, it is extracted as a by-product of orange juice production by centrifugation, producing a cold-pressed oil. It is composed of mostly (greater than 90%) d-limonene, and is often used in place of pure d-limonene. D-limonene can be extracted from the oil by distillation.

Composition
The compounds inside an orange oil vary with each different oil extraction. Composition varies as a result of regional and seasonal changes as well as the method used for extraction. Several hundred compounds have been identified with gas chromatograph-mass spectrometry. Most of the substances in the oil belong to the terpene group with limonene being the dominant one. Long chain aliphatic hydrocarbon alcohols and aldehydes like 1-octanol and octanal are second important group of substances. The presence of sinensetin, a flavone, explains the orange color.

Structural pest control
Both California and Florida have authorized and registered d-Limonene (orange oil) as an active ingredient with the Environmental Protection Agency for the extermination of drywood termites, Formosan termites, and other structural pests. It is the active ingredient of the popular structural termiticide XT-2000. Regarded an alternative to traditional fumigation, d-Limonene orange oil is increasing in popularity as approximately 70% of modern consumers in California prefer local structural chemical injections over traditional "tenting" or fumigation.

Biological pest control
Orange oil can be used in green pesticides for biological pest control. It can exterminate or control ants and other insects by erasing their scent-pheromone trail indicators, or dissolving their exoskeleton, eliminating the infestation or disrupting re-infestation.

The d-limonene in orange oil may be useful to exterminate drywood termites (Incisitermes).

Domestic cleaning agent
Orange oil contains d-limonene, which may be used in cleaning agents as a solvent or added to furniture polish as an aroma.

Hazards
As a main component of orange oil, limonene dissolves skin oils, possibly causing irritation. Commercial use of orange oil, like that found in XT-2000, requires the use of protective gloves, according to EPA-approved labeling. Most reported cases of irritation have involved long-term industrial exposure to the pure compound, e.g. during degreasing or the preparation of paints.

Limonene in orange oil is flammable and is an irritant if ingested, inhaled, or contacts the eyes, and may cause allergic reactions in some people.