Phenol-containing essential oils storage

Phenol-containing essential oils reacted rapidly with zinc, whereas oils containing monoterpenes have been reported to react strongly with aluminum. It is recommended not to use aluminum for long storage of essential oils. 

Since the ancient times, spices have been added to different types of food to improve their flavor and to enhance their storage stability. The intake of herbs and spices is regulated by themselves by means of the flavor intensity of the essential oil. However, antioxidant extracts with high contents of phenolic diterpenes do not necessarily contain essential oils. Particularly, plant material from essential oil production for cosmetic or pharmaceutical products is an interesting side product to be used for the preparation of antioxidative extracts. However, data published by Richheimer et al. (1996) indicated that the deoiled biomass contains markedly less camosic acid than the dried, nondeoiled plant material. 

It is not only lipids but also essential oils which are sensitive to oxidative changes on storage. Sometimes stabilised by synthetic or natural antioxidants, they usually contain substances showing moderate antioxidant activity, but these may be lost by evaporation or oxidised by air oxygen unless more powerful phenolic antioxidants are added. 

The characteristics of wastewater drawn from storage tanks will depend on the quality of the crude oil stored and may contain dissolved inorganics, oil, and suspended solids. The steam condensate from the overhead accumulator can be characterized as having oil, sulfides, mercaptans, and phenol. If barometric condensers are used in vacuum distillation, the condenser water will have very stable oil in emulsion. However, if the barometric condensers are replaced by surface condensers, the condenser water will be essentially free of oil. 

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