10/16 Volume 142 Thannhausen, October 10, english. Sustainably Sourced Pentylene Glycol a Green All-Rounder. N. Konaté, M.

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1 10/16 Volume 142 Thannhausen, October 10, english Sustainably Sourced Pentylene Glycol a Green All-Rounder N. Konaté, M. Nahrwold

2 personal care sustainability Sustainably Sourced Pentylene Glycol a Green All-Rounder N. Konaté, M. Nahrwold * abstract The increasing consumer demand for more natural cosmetics is a continuing global trend. The manufacturers of cosmetics and cosmetic ingredients therefore share a common goal: finding cost-effective bio-based ingredients that work as well as their petrochemical-derived counterparts. Recently, a nature-derived version of the popular synthetic alkanediol Pentylene Glycol has become available on an industrial scale at a competitive price (trade name: Pentiol Green+, by Minasolve). It is produced on the basis of corn cobs and sugarcane bagasse and provides the same multi-functionality as its petrochemical equivalent: skin moisturization, emolliency and antimicrobial protection. However, the novel natural origin of Pentylene Glycol makes it possible to also use it in eco-labelled products. It increases the degree of naturality of cosmetics and reduces their carbon footprint. Furthermore, being an eco-sourced solvent, green Pentylene Glycol provides added value for extracting plant materials. Introduction With the aid of the internet and mobile media, consumers are more educated and better informed than ever before. Global discussions on product safety, environmental compatibility and sustainability affect more and more purchasing decisions. Nonetheless, the willingness of the consumer to pay premium prices for greener products is limited. Suppliers of consumer goods should therefore be able to answer two key questions: 1) How can products be designed which are attractive, safe and sustainable at the same time? 2) How can these products be produced with good margins, yet be cost-effective for the consumer? Here is where the joint creativity of product and ingredient developers is demanded. An actual challenge for the cosmetics industry is the replacement of petrochemical-derived ingredients with substances produced in a sustainable way. In addition, renewable sources for the manufacture of green cosmetic raw materials should ideally not compete with food production. However, not every petrochemical-based raw material can be made from sustainable resources. In many cases, the development of alternative substitutes is required (e.g. nature-derived emollient esters as silicone replacement or polyglyceryl esters instead of polyethylene glycol-based emulsifiers). Since these green substitutes often perform in a different way than the well-established ingredients they are meant to replace, new application technologies may have to be implemented. However, there are some exceptions, like the one described in this article. Sustainable Production The remaining part of squeezed sugar cane, the bagasse, is a waste product of sugar production. Such plant residues are often incinerated or composted. However, bagasse is very interesting for chemists developing natural ingredients. It contains sugar monomers with five carbon atoms, linked together in the form of the indigestible polymer hemicellulose. The same type of sugar polymers can also be found in another food waste, corncob. By splitting the polymeric hemicellulose with water into its components (hydrolysis) and by eliminating water from the resulting monomers xylose and arabinose (dehydration), the raw material furfural can be obtained in a single technical step. This intermediate compound is purified by steam distillation and can be further used as a starting material for various applications (Fig. 1). Due to its easy accessibility and renewable nature, Fig. 1 Production of green Pentylene Glycol from renewable starting material via Green Chemistry 44 sofwjournal /16

3 sustainability personal care furfural is seen as one of the potential key agents of sustainable chemistry [1-3]. The French cosmetic ingredients supplier MINASOLVE offers a sustainably produced version of the popular multi-functional ingredient Pentylene Glycol. This ingredient is obtained by reacting furfural with hydrogen (catalytic hydrogenation). The production of Pentiol Green+ is realized in cooperation with Minasolve s sister company, PENNAKEM in Memphis/ Tennessee, specialized in sustainable chemistry for over 70 years. The large-scale layout of the dedicated production unit provides high cosmetic quality green Pentylene Glycol at a competitive price [4-5]. Pentiol Green+ is a colourless liquid with a faint or no odour, is free of genetically modified organisms, and is COSMOS and ECOCERT approved. Thus, it is suitable for applications in cosmetics certified by such labels. Green Multifunctionality The concept of multifunctionality has been discussed in the cosmetic industry for quite some time (see one of the latest reports in [6]). The idea being that a single raw material takes over the tasks of several individual components. The use of fewer raw materials leads to simpler formulations and shorter development times, with less risks of product instability. The allergy potential may also be lowered. Furthermore, stock management and ingredients handling during manufacture are made easier. Finally, the formula will be more cost efficient without sacrificing performance. Pentylene Glycol, whether synthetic or green, has the essential features of a typical multi-functional raw material: it acts as a skin humectant and emoillent, as a solvent, and as a mild anti-microbial agent. It is also known to improve emulsions stability, appearance and tactile properties, through its impact on droplets size [7]. Pentylene Glycol is stable, independent of the surrounding ph value. In addition, it is miscible with both water and polar oils. Therefore, it is easy to use, and generally compatible with almost all galenic forms, including anhydrous products (e.g. lipsticks). There are no known incompatibilities with standard cosmetic raw materials. In the following paragraphs, the multifunctionality of green Pentylene Glycol will be further described. It will be demonstrated that going green does not necessarily mean compromising on performance. Green Preservation The renewable form of Pentylene Glycol is the first green alkanediol which proved to be able to preserve cosmetic formulations as a standalone antimicrobial ingredient (Tab. 1). Positive results of microbial challenge tests, meeting criteria A of the standard ISO 11930, have been obtained for both O/W emulsions and for surfactant-based formulations. Typically, concentrations of 3 to 5 % of green Pentylene Glycol are required for full protection. Pentylene Glycol can be incorporated into aqueous phases, but it can also be added after completion of the emulsification step. The second process increases the antimicrobial activity in multi-phase formulations. Formulation ph Preservation system Challenge Test Results (ISO 11930)* Use Overall level AB CA PA SA EC Result O/W emulsion 5.5 unpreserved - FAIL FAIL FAIL FAIL FAIL FAIL (see Tab. 2) 5.5 GPG 5.0 % A A A A A A Shampoo 5.5 unpreserved - FAIL FAIL FAIL FAIL FAIL FAIL (see Tab. 3) 5.5 GPG 5.0 % A A A A A A 5.5 BLEND 1: GPG/Water/Sodium Benzoate/Benzoic acid 2.0 % A A A A A A BLEND 2: % A A A A A A GPG/Glyceryl Caprylate/Caprate O/W emulsion 5.5 BLEND 3: A A A A A A (see Tab. 2) 2.0 % 7.0 GPG/Phenylpropanol A A A A A A 5.5 Phenylpropanol as in 2 % of BLEND 3 A A FAIL FAIL A FAIL 5.5 GPG as in 2 % of BLEND 3 FAIL FAIL FAIL FAIL B FAIL *PASS/FAIL ABBREVIATIONS A = PASSES criteria A of ISO B = PASSES criteria B of ISO FAIL = Does not pass criteria A or B of ISO GPG: Green Pentylene Glycol AB: Aspergillus brasiliensis CA: Candida albicans SA: Staphylococcus aureus PA: Pseudomonas aeruginosa EC: Escherichia coli Tab. 1 Challenge tests results according to ISO for green Pentylene Glycol (GPG) as standalone preservative and in various blends. The blue box highlights synergistic effects between GPG and Phenylpropanol 10/ sofwjournal 45

4 personal care sustainability Thus, green Pentylene Glycol can effectively protect cosmetic formulations, as already known for the synthetic version [8]. Even more effective than green Pentylene Glycol alone are its combinations with classical or alternative preservatives. Generally, the preservative properties are significantly increased by Pentylene Glycol (boosting effect). Combinations of green Pentylene Glycol with the classical preservatives Benzoic Acid and Sodium Benzoate, as well as with the alternative protective materials Glyceryl Caprylate/Caprate and Phenylpropanol, are summarized in Tab. 1. These optimized mixtures display specific advantages: Phase Raw material INCI name % Water Water ad 100 A Xanthan Gum PC Xanthan Gum 0.5 Cetearyl Glucoside (and) Emulgade PL 68/ Cetearyl Alcohol Butyrospermum Parkii (Shea) Lipex SheaSoft 3.0 Butter B Simmondsia Chinensis (Jojoba) Jojoba Oil 3.0 Seed Oil Corylus Avellana (Hazel) Hazelnut Oil 3.0 Seed Oil C Preservative system or polyhydric alcohol See Tab. 1 0 to 5.0 Bioxan T70 Tocopherol 0.1 D Citric acid solution Water (and) Citric Acid qs When combining green Pentylene Glycol with Benzoic Acid, the versatile solvent properties of the alkanediol pay off. Both the free carboxylic acid and its salt, sodium benzoate, are effectively stabilized in aqueous solution. A blend of Benzoic Acid and Sodium Benzoate in green Pentylene Glycol/water, adjusted to, for example ph 6, does not generate any large ph variations when added to formulations. Furthermore, the preservative effect of Benzoic Acid is amplified. The corresponding blend (INCI: Pentylene Glycol, Water, Sodium Benzoate, Benzoic Acid; trade name: MinaSolve Green B) is a COSMOS-compliant way to achieve an effective broad spectrum preservation of natural cosmetics [9]. Green Pentylene Glycol in combination with Glyceryl Caprylate/Caprate (trade name: MinaSolve Green C) is a versatile solution to protect green cosmetics, especially against bacteria and yeasts. The blend is made of 100 % non-ionic, nature-derived ingredients from renewable sources. Its ph-neutral composition allows for a wide range of applications. Blending green Pentylene Glycol with the nature-identical aroma compound Phenylpropanol (trade name: MinaSolve Green A, available as of 2017) allows for preservation at high ph values. This combination is extremely Tab. 2 O/W emulsion, subjected to challenge tests and sensory evaluation effective, in particular against yeasts and moulds. An additional benefit of this blend is its low impact on formulation s odour, due to the relatively low level of aromatic alcohol. Green Skin Care Properties Fig. 2 Humectant properties of Pentylene Glycol (Pentiol Green+) and glycerin, measured by corneometry In addition to its antimicrobial properties, Pentylene Glycol has positive effects on the skin and its feel [9]. The moisturizing effect of the green version of this dihydric alcohol was investigated in comparison to the trihydric alcohol glycerine, also nature-derived, and well-known for its moisturizing properties. In a consumer study at an independent laboratory (PhD Trials/Lisbon), green Pentylene Glycol and glycerine were applied as 3 % aqueous solutions to the inner forearms of 12 female volunteers, aged 18 to 65 years. The skin-moisturizing effects of the two test solutions were measured by corneometry. Herein, glycerine and green Pentylene Glycol both showed a long-lasting and statistically equivalent skin moisturizing effect (Fig. 2). In addition to retaining moisture, Pentylene Glycol is also able to positively influence the skin feel of cosmetic formulations. To further investigate this emollient effect, the polyhydric alcohols glycerine, 1,3-propanediol (nature-derived) and green Pentylene Glycol were incorporated, each at 3 %, into the aqueous phase of an O/W emulsion (see Tab. 2). The three creams were applied, in an internal consumer study, on the back of the hands of 23 human volunteers (male/female, years old). Using a questionnaire, the 46 sofwjournal /16

5 Due to its vegetable origin, it is tempting to use green Pentylene Glycol as an extracting agent and solvent for herbal ingredients. The amphiphilic nature of the alkanediol ensures that both polar and non-polar constituents are extracted from plant materials, and stabilized inside the extract. Since green Pentylene Glycol has a relatively low volatility with a boiling point of 206 C, the extraction can be carried out under atmospheric pressure even at higher temperatures. The skin care properties of green Pentylene Glycol, as described above, make it possible to use the obtained extracts directly into formulations. It is hence not necessary to remove an extraction solvent that is possibly not skin friendly. The ensustainability personal care Phase Raw material INCI name % Water Water ad 100 Xanthan Gum PC Xanthan Gum 0.6 A Coco Glucoside Coco Glucoside 15.0 Plantapon ACG HC Sodium Cocoyl Glutamate 5.0 Tego Betain F 50 Cocamidopropyl Betaine 5.0 B Preservative system See Tab. 1 0 to 5.0 C Citric acid solution Water (and) Citric Acid qs Tab. 3 Sulphate-free shampoo, subjected to challenge tests three products were evaluated in eight different categories, with scores from 0 (low) to 10 (high). The results are shown in Fig. 3. The test persons generally preferred the skin feel generated by the two dihydric alcohols compared to the trihydric glycerin. Green Pentylene Glycol rated highest in 7 out of the 8 categories, including the categories Rapid absorption through the skin, Low tackiness and Did you like the product?. These findings underscore the attractive skincare properties of green Pentylene Glycol. Green Extraction ergy-intensive step of solvent exchange is also bypassed, and the attractive skincare properties of the solvent are gained in addition. Thanks to the antimicrobial activity of green Pentylene Glycol, some microorganisms potentially present are effectively killed. In addition, the extracts are self-preserved and therefore protected against a re-infestation by microbes. In order to exemplarily evaluate the extraction power, 10 g of dried Mentha piperita (peppermint) leaves were suspended in 50 g each of green Pentylene Glycol and ethanol. Both mixtures were heated to C and stirred at this temperature for 15 minutes. After cooling, the solid constituents were filtered and the filtrates were analyzed by HPLC (Fig. 4). Both green solvents showed a similar efficacy and selectivity. Safe for Use Finally, to ensure product safety, the new green version of Pentylene Glycol was subjected to a clinical human repeated insult patch test (HRIPT) at an independent laboratory (PhD Trials/Lisbon). The product was applied undiluted, on 101 male and female volunteers (18 to 65 years old) ten times over a period of 36 days. During the whole test period of 40 days, no signs of skin irritation or sensitisation occurred in any of the test subjects. It can therefore be assumed that the Pentylene Glycol produced from natural resources is at least as safe an ingredient as the petrochemically produced one. A similarly positive assessment of Pentylene Glycol was also given by the Expert Panel of the Cosmetic Ingredient Review in his recently published final safety report [10]. Fig. 3 Comparative usage and emollient properties of green Pentylene Glycol and two other green humectants Fig. 4 Qualitative and semi-quantitative HPLC-analysis (UV detection at 254 nm) of Peppermint leaf extracts obtained by using green Pentylene Glycol (Pentiol Green+) and Ethanol as extraction agents 10/ sofwjournal 47

6 personal care sustainability Summary The recently introduced green version of 1,2-Pentanediol (INCI: Pentylene Glycol, trade name: Pentiol Green+) is sustainably produced on a large scale from non-food vegetable raw materials. This new cost-effective version of a well-known ingredient opens up new opportunities for applications in eco-certified cosmetics. The multifunctionality of Pentiol Green+ includes antimicrobial protection of formulations, moisturization of the skin, sensory improvement of skin-care products, as well as solubilisation and extraction of natural components. Green Pentylene Glycol also acts as an effective preservative booster, e.g. in blends with the antimicrobial agents Phenylpropanol, Benzoic Acid, and Glyceryl Caprylate/Caprate (trade names: MinaSolve Green A/Green B/Green C respectively). Many different types of eco-certified cosmetics can therefore be effectively protected. Finally, the green version of Pentylene Glycol allows for decreasing the carbon footprint of personal care products without compromising on performance. Literature [1] D.T. Win, Furfural Gold from Garbage, AU Journal of Technology, 8(4): (2005) [2] K.J. Zeitsch, The Chemistry & Technology of Furfural and its Many By-Products, Elsevier, Köln (2000) [3] A.S. Mamman et al., Furfural Hemicellulose/xylosederived biochemical, Biofuels, Bioproducts and Biorefining, 2(5): (2008) [4] F. Manfré, Green Chemistry as solution for alternative preservation, Expression Cosmétique, (2014) [5] F. Manfré et al., A biobased multifunctional ingredient, Specialty Chemicals Magazine, 35(3): (2015) [6] [7] R. Pillai et al., 1,2-Pentanediol a Multifunctional Ingredient for Personal Care Applications, SOFW Journal, 131(6): (2005) [8] M. Akedo et al., Antimicrobial Action of Aliphatic Diols and their Esters, Journal of Food Science, 42(3): (1977) [9] Minasolve S.A.S., MinaSolve Green B, Household and Personal Care Today, 9(2): (2015) [10] W. Johnson et al., Safety Assessment of 1,2-Glycols as Used in Cosmetics, International Journal of Toxicology, 31(Supp. 2): 147S-168S (2012) contact * Dr. Nadia Konaté Dr. Markus Nahrwold Minasolve Germany GmbH Am Haupttor Gebäude Leuna Germany contact@minasolve.com 48 sofwjournal /16