Classification of Fragrances and Fragrance Mixtures Based on Interfacial Solubilization

Abstract

In the present study, the influence of perfumes on the interfacial curvature of microemulsions is investigated. The hydrophilic-lipophilic deviation (HLD) concept was applied to nonionic Winsor I type systems (O/W microemulsions in equilibrium with an oil excess phase) containing a mixture of oils with isopropyl myristate as supporting oil and a variety of liquid solutes as co-oil for which an Equivalent Alkane Carbon Number of the mixture (EACN mix ) was defined. Temperature was used as a formulation variable and the phase inversion temperature change, provoked by the solubilization of different solutes, was determined. The hydrodynamic radius of the droplet and the interfacial solubilization of fragrances were measured subsequently and correlated to the EACN mix . In a first step, selected perfumery raw materials (PRMs) were used as solutes and were studied separately. It was demonstrated that the PRMs can be classified in interfacial solubility according to their chemical functionalities and they follow the order alcohols [ aldehydes [ terpenes [ aromatics [ alkanes. Solutes that lead to low EACN mix values (\6) have preferential interfacial solubility and provoke strong curvature changes, whereas those leading to higher EACN values ([6) typically do not change the curvature significantly. The HLD method was also applied to complex fragrances and it was demonstrated that they can be considered as single, non-polar entities, and studied as such instead of investigating each raw material included in the composition separately. Determination of the dimensionless number EACN mix offers the possibility of classifying perfumes in an environment similar to surfactant formulations of typical consumer products and to predict the interaction with the surfactant base according to the rules established on the basis of the individual raw materials.

Effect of surfactant concentration on the hydrophobicity of polydisperse alkyl ethoxylates

“…Recent industry-led presentations at American Oil Chemists Society (AOCS) meetings have introduced experimental and modeling approaches to account for these effects and their impact on surfactant formulation (Dado & Lang, 2021;Ghayour, 2021;Natali & Acosta, 2021). There are now clear connections between phase inversion conditions (HLD = 0) and the performance of formulations in detergency (Phaodee & Sabatini, 2020;Raney et al, 1987;Raney & Benson, 1990;Saito et al, 1985;Thompson, 1994;Tongcumpou et al, 2003); the performance of formulations used to decontaminate oilimpacted soils (Acosta & Quraishi, 2014;Childs et al, 2005;Kibbey & Chen, 2008;Quraishi et al, 2015); the performance of phase inversion methods to produce nanoemulsions (McClements, 2011;Solans et al, 2005); the performance of demulsifiers (Rond on et al, 2006); the formation and breaking of emulsions (Kiran & Acosta, 2015); the formulation with fragrances (Bouton et al, 2009;Tchakalova & Fieber, 2012); the formulation of skin cleaning products (Acosta, 2020), among many others. The connection between the phase inversion conditions and optimal enhanced oil recovery is well known and covered in the classic textbook of Bourrel and Schecter (1988).…”

Co‐surfactant, co‐solvent, and hydrotropic properties of some common cooling agents

“…In a previous article a general method for the estimation of surface activity of perfumery ingredients, based on the fluctuation of PIT in a reference system composed of water, surfactant (C 10 E 5 ), and IPM, was introduced . This method is not limited to perfumery ingredients.…”

“…In a previous work, we introduced the parameter EACNmix as a measure of the surface activity of the solute with respect to the reference system. We found that solutes with an EACNmix value of more than 5.5 did not express interfacial activity, whereas those with an EACNmix value of less than 5.5 had strong interfacial affinity, leading to a significant swelling of the droplet.…”

“…The PIT method is used as described by Tchakalova and Fieber . Winsor‐type systems were used, composed of an ethoxylated surfactant (C 10 E 5 ), water, and oil (IPM in this study) – a solvent often used in perfumery applications.…”

Formulation in Surfactant Systems: From-Winsor-to-HLDN

“…Usually, encapsulating the essence in the droplets will provide a more lasting effect due to a controlled release. The high volatility of such small substances in an aqueous phase can make their evaporation fast [374,375].…”