Please look at the following below links which may help you in your work

https://www.agrifarming.in/geranium-oil-extraction-process-methods-uses#google_vignette

Yiu can also manage to do the mechanochemical-assisted extraction (fast and green method) of the essential oils from Geranium.

See the paper in the link below 👇🏾

https://doi.org/10.1016/j.indcrop.2022.115703

Geranium (Pelargonium graveolens) essential oil is widely valued in aromatherapy, perfumery, and cosmetics for its sweet, rosy, and slightly minty fragrance, largely attributed to its major constituents such as citronellol, geraniol, and linalool (Baser & Buchbauer, 2020). The predominant extraction method employed by both large-scale industries and artisanal producers is steam distillation, a technique that is both cost-effective and effective in preserving aromatic volatiles (Tisserand & Young, 2014). Recent advancements in research have elucidated the optimization of parameters such as harvest timing, distillation duration, and temperature to enhance oil quality and yield (Li et al., 2021).

In preparation for steam distillation, the harvesting of the aerial parts (leaves and flowering tops) of Pelargonium graveolens is typically conducted when the plant is at or just before the peak flowering stage, as this timing corresponds with higher concentrations of volatile compounds (Rajeswara Rao et al., 2016). Early morning harvest is frequently practiced because plant tissues can retain a greater concentration of essential oil at cooler temperatures (Tisserand & Young, 2014). Subsequent to harvesting, the material is often subjected to gentle wilting to reduce surface moisture while minimizing any significant loss of volatiles (Baser & Buchbauer, 2020).

During the steam distillation process, the plant material is loaded into a still where steam is introduced, either from beneath the plant material (hydrodistillation) or via direct injection of steam from a separate boiler (steam distillation proper). The application of heat causes the aromatic molecules to evaporate, which are subsequently captured in a condenser that is chilled by water (Li et al., 2021). The condensation process yields a distillate comprising two phases: an aqueous phase, designated as geranium hydrosol (aromatic water), and an oily phase, which corresponds to the essential oil. Due to its lower density, geranium oil typically rises to the top and can be collected by decantation or separation in a Florentine flask (Rajeswara Rao et al., 2016).

Maintaining a distillation temperature near 100–105°C and closely monitoring the process duration—often between 1.5 and 3 hours—can be critical to achieving optimal oil yields while preventing thermal degradation of volatile compounds (Baser & Buchbauer, 2020). Prolonged distillation times carry the risk of altering the aromatic profile, as lighter constituents may evaporate or degrade if exposed to excessive heat (Tisserand & Young, 2014). Subsequent to the separation of the essential oil, filtration or drying techniques may be employed to remove residual water, employing agents such as anhydrous sodium sulfate. Subsequent storage of the essential oil in amber glass bottles, maintained under conditions of cool, dark conditions, is instrumental in preserving the composition and olfactory characteristics of the oil (Li et al., 2021).

In addition to steam distillation, alternative methods such as hydrodistillation and solvent extraction exist. Hydrodistillation entails the submerging of plant material in water, which is subsequently subjected to boiling. Although it can be used for small-scale productions, careful monitoring is essential to avoid prolonged high-temperature exposure, which can negatively affect oil quality (Rajeswara Rao et al., 2016). Hexane or ethanol is often employed in solvent extraction, yielding a "concrete" and subsequently an "absolute" through the separation of waxes. However, the presence of solvent residues and variations in chemical profiles renders these products more prevalent in fine perfumery than in aromatherapy (Tisserand & Young, 2014).

Recent research highlights that factors such as climate, soil conditions, and genotype variations can significantly influence both yield and chemical composition. For instance, geraniol-to-citronellol ratios may be subject to variation under different environmental or cultivation practices (Li et al., 2021). Notwithstanding, steam distillation remains the preferred technique for producing a clean and therapeutically acceptable geranium essential oil (Baser & Buchbauer, 2020). When executed with precise control of temperature and duration, it effectively captures the characteristic aroma and bioactive constituents that confer the oil's numerous applications in fragrance formulation, skincare, and holistic wellness.

References

Baser, K. H. C., & Buchbauer, G. (2020). Handbook of Essential Oils: Science, Technology, and Applications (2nd ed.). CRC Press.

Li, J., Song, L., Wang, X., & Huang, X. (2021). Influence of distillation parameters on the yield and quality of essential oil from Pelargonium graveolens. Journal of Essential Oil Research, 33(3), 205–213.

Rajeswara Rao, B. R., Kaul, P. N., Mallavarapu, G. R., & Ramesh, S. (2016). The effect of seasonal climatic changes on yield and composition of rose-scented geranium (Pelargonium species) oil is also examined. Industrial Crops and Products, 85, 202–208.

Tisserand, R., & Young, R. (2014). Essential Oil Safety: A Guide for Health Care Professionals (2nd ed.). Churchill Livingstone.

Dear Doctor

Go To

Investigation of geranium oil extraction performance by using soxhlet extraction

• August 2022
• Materials Today Proceedings 72(8)
• DOI: 10.1016/j.matpr.2022.07.276
• By Rajesh Yennam et al.

[Abstract

Geranium oil (Pelargonium graveolens) is widely used as main ingredient in the production of perfumes as well as cosmetics etc. The essential oil is also used in aromatherapy treatment in various health issues occurred in rural areas. In literature, several authors are used the different traditional extraction methods ; such as steam distillation, hydro distillation and solvent extraction etc. In this work, author used the novel technique as soxhlet extraction of geranium oil extraction. The purpose of this work is to investigate the suitable method for getting the higher yield with lower cost and limited facilities. To investigated the performance of soxhlet extraction technique by using different organic solvents like n-Hexane, Methanol, Chloroform, Toluene and Water. Among all the solvents, n-Hexane and Toluene are provided the satisfactory results with soxhlet extraction of geranium oil yield as 0.08-0.1 %. The operating conditions of soxhlet extraction as Temperature (60-12°C) and time (120-240 min). Also, the author calculated the Mass & Energy balances of soxhlet extraction are 6 (V/W) and 75 KW-Hr, whereas for steam distillation Mass & Energy balances are 0.5 (V/W) and 42 KW-Hr. Even though the yield is small compared to steam distillation, but this work will be applicable for lab scale extraction of geranium oil as well as essential oils with lower cost.]