BR102020006868A2 - METHOD OF MODIFYING VEGETABLE OILS, MODIFIED VEGETABLE OIL AND ITS USE - Google Patents

Abstract

method of modifying vegetable oils, modified vegetable oil and its use. presents a modification method using direct transesterification of vegetable oil, with reduced process time and in the presence of an acid catalyst, as an alternative to ethoxylation reactions of vegetable oil with ethylene oxide. the invention also presents a modified vegetable oil, with appropriate physicochemical characteristics and permitting its use in the formulation of cosmetic products, specifically nanoemulsions, lotions, shampoos, and translucent soaps, presenting good sensorial/emollient characteristics, transparency, viscosity and physicochemical properties suitable for application, such as stability during storage and viscosity adjusted with the introduction of salt.

Description

METHOD OF MODIFYING VEGETABLE OILS, MODIFIED VEGETABLE OIL AND ITS USE APPLICATION FIELD

[001] This invention deals with the direct and customized modification of palm kernel oil (PKO) or the fatty acid of palm kernel oil using polyethylene glycol (PEG) through the transesterification reaction for use in transparent cosmetic formulations, such as shampoos and soaps or other formulations that require an emollient component in an aqueous medium. Modified oils, a product of the direct modification of palm kernel oil (PKO) or its fatty acid, are successfully obtained associated with (i) use of an acid catalyst; (ii) catalyst to polyethylene glycol (PEG) ratio, (iii) choice of PEG chain size; (iv) ratio of palm kernel oil to polyethylene glycol); (v) reaction temperature; (vi) reaction time); (vii) solubility and stability in water; and (viii) preservation of the emollient properties of vegetable oil after modification with polyethylene glycol.

DESCRIPTION OF TECHNICAL STATUS

[002] Some vegetable oils, by themselves, have necessary and expected properties in cosmetic formulations both as emollients and in the preparation of derivatives, such as alcohols and esters. Additionally, vegetable oils have good penetration and compatibility with the skin, ability to transport therapeutic agents and supply nutrients, such as tocopherols, carotenoids and fatty acids, essential to it.

[003] Brazil, due to its favorable geographic characteristics, such as its location in a tropical region, high luminosity rates and high average annual temperatures (between 28 °C and 32 °C) has a large production of vegetable oils, with estimates that chemical products from renewable sources represent up to 10% of the national chemical industry.

[004] The extraction of vegetable oils can be done from leaves, seeds, seeds and leguminous plants rich in nutrients, and can be incorporated into other actives, such as emollients, fragrances, dyes, vehicles for applying drugs to the skin and as Basic components of makeup products.

[005] Currently, Brazil ranks fourth in the world in the personal care, perfumery and cosmetics segment, representing 6.6% of the sector's global consumption. In this sense, the chemical modification of vegetable oils, which are non-polar and immiscible in water, makes these substances more easily incorporated into aqueous solutions and emulsions, in order to obtain a more stable formulation with good sensory characteristics.

[006] The process generally used for the hydrophilization of vegetable oils is ethoxylation, which aims to facilitate the incorporation of these oils in hydrophilic formulations of shampoos, liquid soaps and moisturizing lotions. However, ethylene oxide presents thermal instability and high reactivity with other chemical species, including water, which can cause accidents in its processing and manufacturing. Ethylene oxide is also highly toxic, potentially carcinogenic, can cause burns when in contact with the skin, and is highly toxic to the environment. For these reasons, the production process using ethylene oxide requires specific and difficult-to-maintain equipment, in addition to a controlled environment.

[007] In this sense, it is difficult to carry out the hydrophilization of vegetable oils, specifically palm kernel oil without the use of ethylene oxide and even the direct modification of vegetable oils for incorporation in the formulation of shampoos and clear liquid soaps, as well as for the production of oil-in-water (O/W) emulsions.

[008] The search for prior art documents found the document US3288824, entitled "ESTERIFICATION OF TRIGLYCERIDE WITH POLYETHYLENE GLYCOLS AND PRODUCTS" refers to compositions formed by the interaction between fats and oils with polyethylene glycol of molar mass between 200 and 800, at temperatures between 205 and 225°C, in the presence of a basic catalyst such as lime or sodium hydroxide (0.05, 0.2% w/v), for 2 h. The products of the invention, in their original state or in solution, can be useful for producing fine, stable and opaque oil-in-water emulsions. The hydrophilic properties of the product of the invention are weak, which makes it preferential to act as emulsifiers. In another modality, the document describes the use of the product of the invention for use in cosmetic emulsions, such as creams, shampoos, soaps and lotions, both with emollient properties.

[009] The document EP2344616, entitled "NONIIONIC SURFACTANT BLENDS USING SEED OILS" describes a method of direct transesterification in one step of methoxypolyethylene glycol with a seed-derived oil, such as palm oil or palm kernel oil, to produce a mixture of glycerol free, mono, di and triglycerides and ethoxylated methyl ester, with surfactant properties. The invention also provides for the use of the product obtained as a surfactant in detergents, specifically laundry detergents.

[010] The document US8178714, entitled "METHOD TO PRODUCE POLYHYDROXY CARBOXYLIC ACID ESTERS OF POLYETHYLENE GLYCOL" describes a method of esterification of polyols without the use of catalysts and without the need for an additional purification step, making the method faster and cheaper than those commonly used. The document also discloses compositions using the product obtained by the method, which are suitable as emulsifiers, solubilizers or wetting agents in cosmetic products. Finally, the invention foresees the use of polyhydroxy fatty acids of animal or vegetable origin, in addition to the use only of 9,10-dihydroxystearic acid.

[011] Thus, taking the documents found by the searches, it is concluded that there are no documents that anticipate, in isolation, what is revealed by the present invention, so that the solution proposed here for the direct transesterification of oil from palm kernel is entirely new. Still, there are no documents in the researched literature that suggest the teachings proposed here, endowing the invention with an inventive step.

BRIEF DESCRIPTION OF THE INVENTION

[012] Some vegetable oils have, per se, the necessary and expected properties in cosmetic formulations, either as an emollient substance, or as a base in the preparation of derivatives. In addition, vegetable oils have good penetration and compatibility with the skin, ability to transport therapeutic agents and provide nutrients.

[013] The non-polar property and immiscibility of oils in water, makes its incorporation process in hydrophilic formulations complicated, making the oil hydrophilization step necessary. The currently existing methods for the hydrophilization of these substances demand the use of dangerous reagents, which require use in a controlled environment, specific and expensive equipment, in addition to being toxic and requiring several purification steps.

[014] In this sense, it is an objective of the invention to provide a method of direct modification of palm kernel oil (PKO), or the fatty acid of palm kernel oil with polyethylene glycol (PEG), in the presence of an acid catalyst, for formulating cosmetics , specifically shampoos, lotions and translucent liquid soaps.

[015] It is also an objective of the invention to provide a modified oil, product of the proposed method, which has water solubility, compatibility with components commonly used in shampoo formulation, ability to form stable oil-in-water emulsions without the additional introduction of emulsifier and to solve the problem of using ethylene oxide, which has all the aforementioned disadvantages. The use of modified oil is foreseen in translucent cosmetic products, especially shampoos, soaps and lotions, in addition to oil-in-water (O/W) emulsions without the need for emulsifiers.

BRIEF DESCRIPTION OF THE DRAWINGS

• - a figura 1 ilustra o esquema empregado na reação de modificação do óleo de palmiste (PKO) com PEG em escala de laboratório;
• - a figura 2 ilustra o aspecto do produto final obtido entre o óleo de palmiste (PKO) e o PEG, nas mesmas condições da reação da figura 1 (tempo, temperatura, proporção molar), porém sem a utilização do catalisador. A porção superior da solução corresponde ao óleo de palmiste, e a porção inferior é o PEG;
• - a figura 3 ilustra o aspecto do produto da mistura entre o óleo de palmiste (PKO) com o PEG-400 (c) e o PEG-600 (d) sem a introdução do catalisador ácido, em que também é possível de se observar a separação de fases, sendo o sobrenadante o óleo de palmiste, e a fase de baixo, o PEG;
• - a figura 4 ilustra o aspecto dos óleos modificados com PEG-400 (a) e PEG-600 (b) para diferentes concentrações de catalisador e diferentes tempos de reação;
• - a figura 5 ilustra os espectros FT-IR do óleo de palmiste, do PEG-400 e dos óleos modificados. Em (a) PM0120 conduzida em 1 h e em (b) PM0106 conduzida em 3 h;
• - a figura 6 ilustra os espectros FT-IR do óleo de palmiste, do PEG-600 e dos óleos modificados. Em (a) PM0118 conduzida em 1 h e em (b) PM0108 conduzida em 3 h; em que as análises de FT-IR foram realizadas com o objetivo de identificar as bandas características do óleo PKO, dos PEGs e dos óleos modificados. No espectro do óleo PKO o pico em 2922 - 2855 cm-1 corresponde ao estiramento -C-H das cadeias longas do alquil, enquanto os picos 1743, 1458 e 1158 cm-1 correspondem os estiramentos C=O, C=C e C-O, respectivamente. No espectro do PEG-400 o pico mais largo, em 1100 cm-1 e 1300 cm-1 corresponde ao estiramento éter C-O-C. Da mesma maneira, a banda em 2960 e 2869 cm-1 corresponde ao estiramento de vibração -CH2. No espectro do PEG-600 as bandas em 2862, 1462 e 1347 cm-1 correspondem as vibrações C-H enquanto as bandas centradas em 1100 cm-1 e 1300 cm-1 são originárias das ligações C-O-C do PEG. Também é possível verificar a banda da hidroxila (–OH) em aproximadamente 3389–3420 cm-1.
• - a figura 7 ilustra as curvas de tensão superficial em função da concentração dos óleos modificados com PEG-600 (PM0108) e PEG-400 (PM0120) em água deionizada;
• - a figura 8 ilustra o perfil da viscosidade complexa em função da temperatura das amostras PEG-600, óleo de palmiste, mistura PM0107 (sem catalisador) e reação PM0108 (com catalisador);
• - a figura 9 ilustra o aspecto do xampu com 4 % (m/m) do óleo de palmiste sem modificação (a) após preparação e (b) após 15 dias de repouso a (23±2) °C, em que o sobrenadante corresponde ao óleo de palmiste;
• - a figura 10 ilustra o aspecto do xampu com 4 % (m/m) do óleo de palmiste modificado com PEG-600 (PM0108) (a) após preparação e (b) após 15 dias de repouso a (23±2) °C;
• - a figura 11 ilustra o aspecto do xampu com 4 % (m/m) do óleo de palmiste modificado com PEG-400 (PM0106) (a) após preparação e (b) após 15 dias de repouso a (23±2) °C;
• - a figura 12 ilustra o perfil de viscosidade dos xampus com óleo modificado com PEG-600, PEG-400 e o padrão (sem óleo modificado);
• - a figura 13 ilustra o aspecto das nanoemulsões O/A com 5 % (m/m) do óleo modificado com PEG-600 (a) antes do teste de estabilidade e (b) após 15 dias na estufa a 40 °C, em que, tanto na imagem de cima quanto na imagem de baixo temos, da esquerda para direita: PM0118, PM0108, PM0116 e PM0112; e
• - a figura 14 ilustra o cromatograma do óleo de palmiste (PKO) utilizado nesta invenção.

[016] The subject matter of this Invention will be fully clear in its technical aspects from the detailed description that will be made based on the figures listed below, in which:

• - Figure 1 illustrates the scheme used in the modification reaction of palm kernel oil (PKO) with PEG on a laboratory scale;
• - figure 2 illustrates the appearance of the final product obtained between palm kernel oil (PKO) and PEG, under the same reaction conditions as in figure 1 (time, temperature, molar ratio), but without using the catalyst. The upper portion of the solution corresponds to palm kernel oil, and the lower portion is PEG;
• - Figure 3 illustrates the appearance of the product of the mixture between palm kernel oil (PKO) with PEG-400 (c) and PEG-600 (d) without the introduction of acid catalyst, in which it is also possible to observe phase separation, with the supernatant being palm kernel oil and the bottom phase being PEG;
• - Figure 4 illustrates the appearance of oils modified with PEG-400 (a) and PEG-600 (b) for different catalyst concentrations and different reaction times;
• - Figure 5 illustrates the FT-IR spectra of palm kernel oil, PEG-400 and modified oils. In (a) PM0120 conducted in 1 h and in (b) PM0106 conducted in 3 h;
• - Figure 6 illustrates the FT-IR spectra of palm kernel oil, PEG-600 and modified oils. In (a) PM0118 is conducted in 1 h and in (b) PM0108 is conducted in 3 h; in which the FT-IR analyzes were performed in order to identify the characteristic bands of PKO oil, PEGs and modified oils. In the PKO oil spectrum, the peak at 2922 - 2855 cm-1 corresponds to the -CH stretch of the long chains of the alkyl, while the peaks 1743, 1458 and 1158 cm-1 correspond to the C=O, C=C and CO stretches, respectively . In the PEG-400 spectrum the broadest peak at 1100 cm-1 and 1300 cm-1 corresponds to the COC ether stretch. Likewise, the band at 2960 and 2869 cm-1 corresponds to the vibration stretch -CH2. In the PEG-600 spectrum, the bands at 2862, 1462 and 1347 cm-1 correspond to CH vibrations while the bands centered at 1100 cm-1 and 1300 cm-1 originate from the COC bonds of the PEG. It is also possible to verify the hydroxyl band (–OH) at approximately 3389–3420 cm-1.
• - Figure 7 illustrates the surface tension curves as a function of the concentration of oils modified with PEG-600 (PM0108) and PEG-400 (PM0120) in deionized water;
• - Figure 8 illustrates the complex viscosity profile as a function of the temperature of samples PEG-600, palm kernel oil, PM0107 mixture (without catalyst) and PM0108 reaction (with catalyst);
• - Figure 9 illustrates the appearance of the shampoo with 4% (m/m) of palm kernel oil without modification (a) after preparation and (b) after 15 days of rest at (23±2) °C, in which the supernatant corresponds to palm kernel oil;
• - Figure 10 illustrates the appearance of the shampoo with 4% (m/m) of palm kernel oil modified with PEG-600 (PM0108) (a) after preparation and (b) after 15 days of rest at (23±2) ° Ç;
• - Figure 11 illustrates the appearance of the shampoo with 4% (m/m) of palm kernel oil modified with PEG-400 (PM0106) (a) after preparation and (b) after 15 days of rest at (23±2) ° Ç;
• - Figure 12 illustrates the viscosity profile of shampoos with oil modified with PEG-600, PEG-400 and the standard (without modified oil);
• - Figure 13 illustrates the appearance of the O/W nanoemulsions with 5% (m/m) of the oil modified with PEG-600 (a) before the stability test and (b) after 15 days in the oven at 40 °C, in that in both the top and bottom image we have, from left to right: PM0118, PM0108, PM0116 and PM0112; and
• - figure 14 illustrates the chromatogram of palm kernel oil (PKO) used in this invention.

DETAILED DESCRIPTION OF THE INVENTION

• - o polietilenoglicol tem massa molar na faixa de 400 a 600 g/mol e é empregado na proporção de 1:35 a 1:2 em relação ao óleo vegetal; e o catalisador empregado é um catalisador ácido, empregado na concentração de 0,1 % a 0,25 % (m/m).

[017] In accordance with the objectives presented through the brief description and the findings that it is possible to modify palm kernel oil (PKO) with polyethylene glycol (PEG), in the presence of a specific acid catalyst and taking into account the proportion of oil/PEG with improvements in its physicochemical characteristics, this patent application presents a METHOD OF MODIFYING VEGETABLE OILS by direct esterification, using polyethylene glycol (PEG) and specific catalysts, in which:

• - polyethylene glycol has a molar mass in the range of 400 to 600 g/mol and is used in a proportion of 1:35 to 1:2 in relation to vegetable oil; and the catalyst employed is an acid catalyst, employed at a concentration of 0.1% to 0.25% (m/m).

[018] The method also provides that the catalyst used is chosen from the group comprising butylstannoic acid tin (II) 2-ethylhexanoate, dibutyl tin oxide, modified dibutyl tin oxide and dibutyl tin dilaurate and that the The reaction takes place at a temperature ranging from 200 °C to 300 °C, for a time of 1 h to 5 h, under mechanical agitation and a nitrogen gas atmosphere.

[019] In one embodiment, the method predicts that the catalyst used is butylstannoic acid (Fascat® 4100) and that the reaction takes place at a temperature in the range of 200 °C to 300 °C, for a time of 1 ha 5 h, under mechanical agitation and nitrogen gas flow.

[020] In a second embodiment of the method, the catalyst used is tin 2-ethyl hexanoate and the reaction takes place at a temperature in the range of 200 °C to 300 °C, for a time of 1 h to 5 h , under mechanical agitation and gaseous nitrogen flow.

[021] In a third embodiment of the method, the catalyst used is any catalyst from the Fascat® line with food grade produced by the company PMC Organometallix and that the reaction occurs at a temperature in the range of 200 °C to 300 °C, by a time of 1 h to 5 h, under mechanical agitation and nitrogen gas flow.

[022] The present invention also presents a MODIFIED OIL, product of the method disclosed herein, which has a hydroxyl index in the range of 133.00 to 180.12 mgKOH/g and percentage of glycerol in the range of 1.5 to 2, 0 and pH in the range of 4.68 to 6.37 in 5% solution (m/m) in deionized water and carbon distribution shown in Table 1.
Table 1 - Composition of palm kernel oil used in the present invention

[023] The vegetable oil of the present invention also has surface tension in the range of 30.0 to 31.7 dynas/cm and viscosity in the range of 60.0 to 115.0 cPa.s and turbidity in the range of 9.9 at 432 UNT in 5% (m/m) solution in deionized water.

[024] It is a last object of the invention the USE OF MODIFIED VEGETABLE OIL in the formulation of cosmetic products, specifically in the formulation of shampoos, translucent soaps and nanoemulsions of the oil/water type.

EXAMPLES

[025] From the examples below, it is possible to illustrate one of the numerous ways of carrying out the present invention, without the intention of limiting its scope.

Example 1 - Modification of palm kernel oil (PKO) with polyethylene glycol (PEG)

[026] The modification reactions of palm kernel oil, or its fatty acid, were conducted with two types of polyethylene glycol, different in their molar mass (400 and 600 g/mol), using butylstannoic acid (Fascat® 4100) as a catalyst. The effect of catalyst concentration, reaction time and PEG type were analyzed statistically. Palm kernel oil was modified and applied in the production of clear shampoos (turbidity less than 100 NTU). Stable andiroba oil-in-water nanoemulsions were obtained with palm kernel oil modified with PEG-600 and PEG-400, without the introduction of another emulsifier.

[027] Physical-chemical properties, such as solubility in water and properties that ensure the applicability of the product obtained from the proposed method in cosmetic formulations, such as the emollient property were controlled depending on the type of PEG, reaction time and concentration of the catalyst.

[028] Palm kernel oil (PKO) was directly modified with PEG-400 and PEG-600 in the presence of butylstannoic acid, in a proportion ranging from 0.05% to 0.3% in relation to the total mass of oil and polyethylene glycol (PEG). PEG was used in excess to favor the formation of mono and diester of palm kernel oil, as it is a reversible reaction. The molar ratio between oil and PEG used was equal to 1:3.1 and 1:2, maintaining the ratio of 1 mol of oil to 1 mol of PEG.

[029] The reactions were conducted in a glass flask, coupled to the reflux condenser, thermocouple, mechanical stirrer and N2 bubbler, as can be seen in figure 1. The reactions were maintained at a temperature of (200±5) °C , with a reaction time between 1 and 5 hours. In the verification step, the modification of palm kernel oil was followed by measures of solubility of the reaction mixture in water, for different reaction times. The products obtained were characterized in relation to surface tension, viscosity, water solubility, presence of functional groups, appearance and pH. The modified oils were evaluated in shampoo formulations which, in turn, were characterized in relation to their viscosity profile and stability at different concentrations of sodium chloride. The modified oils were also evaluated in water-in-oil (W/O) emulsions, without the introduction of auxiliary emulsifier.

• - concentração de catalisador;
• - tempo de reação; e
• - tipo de PEG empregado.

[030] Considering the reactions of vegetable oil with PEG, either directly or via esterification, and the alternatives for the use of ethylene oxide, three factors were raised that could interfere in the modification of the oil:

• - catalyst concentration;
• - reaction time; and
• - type of PEG used.

Tabela 3 - Fatores e seus respectivos níveis adotados na modificação do óleo de palmiste com PEG-400 e PEG-600 na presença do ácido butilestanóico como catalisador

[031] To analyze the three factors together, we used the design of two-level experiments (+1 and -1), type 2k (with k equal to 3). All experiments were performed in duplicate, totaling 16 reactions. The matrix of experiments was generated using the minitab 17 statistical software (Table 2). Table 3, in turn, shows the factors and their respective numbers adopted in the modification of palm kernel oil.
Table 2 - Coded matrix of the planning of palm kernel oil modification reactions as a function of catalyst concentration, type of PEG and reaction time

Table 3 - Factors and their respective levels adopted in the modification of palm kernel oil with PEG-400 and PEG-600 in the presence of butylstannoic acid as catalyst

[032] The carbonic distribution of palm kernel oil obtained via gas chromatography shows a distribution of saturated fatty acids in greater concentration, with a prevalence of lauric acid (C12), followed by myristic acid (C14) and unsaturated oleic acid (C18') , as seen in Figure 14 (or Table 1). Comparing the carbon distributions presented in the literature for palm kernel oil, it can be seen that there are no significant differences between the results obtained here and those reported in the literature.

[033] According to what is already known in the state of the art, palm kernel oil is a source of saturated acid rich in C12 and also has other significant chains, such as myristic acid and oleic acid with an unsaturation. Thus, palm kernel oil rich in lauric acid was used in this work, with saponification index equal to 249.11 mgKOH/g of oil, average molar mass close to 675 g/mol and iodine index equal to 18.0 mgKOH/ g.

[034] The acidity index (AI) indicates the concentration of fatty acids and the iodine index (IO) indicates the presence of unsaturations in the oil. According to the results of the carbonic distribution of palm kernel oil, lauric acid is found in a greater proportion (43.84%), has low levels of acidity and unsaturation, which results in a lower probability of the occurrence of oxidation during the reactions of modification with PEG.

Example 2 - Results

[035] In the process of direct modification of palm kernel oil with PEGs, some reactions were carried out without the introduction of the catalyst (butylstannoic acid) and with the introduction of the catalyst at different concentrations. The molar ratio defined and used between palm kernel oil and PEG was equal to 1:3.1 and 1:2 (oil/PEG) in order to work with excess PEG to react with the fatty acid and directly with the triglyceride. The ideal reaction temperature was between 200 - 230 °C. Some reactions to verify the chemical modification of palm kernel oil were carried out.

[036] The reactions PM0105 and PM0107 were carried out by mixing palm kernel oil (at 40 °C) with PEG-400 and/or PEG-600, respectively, with a molar ratio equal to 1:3.1 (oil /PEG). The mixture was subjected to heating until reaching (200±5) °C under mechanical agitation, for 3 and 5 hours.

[037] Figure 2 shows the appearance of the product obtained after 3 h, without the introduction of the catalyst. According to this figure, there is a phase separation between palm kernel oil, superior, and PEG, inferior, indicating the absence of modification and/or incorporation of both PEG-400 and PEG-600.

[038] After reducing the temperature of the reaction medium to (23±2) °C, the palm kernel oil precipitated, forming a white solid in the upper part of the container, and a liquid phase in the lower part (figure 3c and 3d). The solidification of palm kernel oil is related to the low rate of modification, resulting in a solidification temperature close to the solidification temperature of palm kernel oil (22.2 °C). The same result was observed for the reaction carried out with a ratio of 1:2 oil/PEG.

[039] After the modification reactions of palm kernel oil, the solubility tests of modified oils with PEG-400 or PEG-600 in deionized water were performed. The results show that the solution prepared with PM0108 oil was transparent for the two concentrations used. The solutions prepared with the oil modified with PEG-400 (PM0106) presented a slightly opaque/cloudy aspect from 0.4 g/L onwards.

[040] These results show that, for the same concentration of catalyst employed, the oil modified with PEG-400 does not have the same solubility in water as the oils modified with PEG-600. However, by increasing the catalyst concentration, the solubility increases. Considering that PEG-600 has more charge than PEG-400, the difference in solubility of modified oils may be related to the molar mass of PEG and a preferential reaction of PEG-600 with triglyceride.

[041] In addition, the cloudy appearance of water in the presence of oil modified with PEG-400 may be related to its cloud point in water for concentrations above 0.4 g/L, which results in phase separation.

[042] It is important to note that the mixture between PEG600 and palm kernel oil without the catalyst resulted in a product with phase separation (no reaction occurred), that is, the presence of the catalyst has an effect on the modification of the oil, as well as the ratio of oil to PEG.

Example 2.1 - Appearance and pH

[043] After carrying out the reactions in the presence of catalyst, the aspects of modified oils in relation to phase separation (stability), formation of lumps, formation of precipitates, color and odor were analyzed. Both modified oils and oil-in-water emulsions at a concentration of 5% (m/m) were analyzed. Statistical treatment was performed considering the classification in relation to aspect and turbidity: 1 for turbidity; 3 for slightly cloudy; and 5 for translucent.

[044] Figure 4 shows the appearance of the products obtained with PEG-400 (a) and PEG-600 (b) after 60 days of storage at room temperature. The reactions carried out with PEG-400 and 0.2% of catalyst presented a different final appearance depending on the reaction time. The product of the PM0106 reaction carried out in 3 h had a cloudy appearance, while the product of the PM0117 reaction carried out in 1 h had a translucent appearance. The same behavior was observed for the products obtained with the reactions PM0110 and PM0122 conducted with 0.1% of catalyst and times of 1 and 3 h, respectively.

[045] These results show that the concentration of the catalyst has influence on the final appearance of products modified with PEG400. However, the reaction time has a greater influence on the appearance of the oil modified with PEG-400. Previous studies had already shown that the monoester/diester ratio increases with increasing PEG molar mass for the same fatty acid. Thus, higher concentrations of diester may have been formed within 3 hours of reaction, resulting in greater product opacity when one of the reagents is PEG-400.

[046] As for the products obtained with PEG-600, the final appearance of the product was translucent, indicating that the catalyst concentration and reaction time did not affect the final appearance of the modified oil. For reactions with PEG-600, the formation of monoesters prevails, soluble in the applied system and, regardless of the time or concentration of the catalyst, the product is translucent.

[047] The hydroxyl index and free glycerol content were analyzed for some experiments, and the results are described in table 4.
Table 4 - Hydroxyl index and free glycerol content of oils modified with PEG-400 and PEG-600

[048] Regardless of the reaction time used, the products obtained with the PEG-400 had a lower hydroxyl index compared to the products obtained with the PEG-600, which indicates the preferential formation of PEG monoester over the diester for the PEG-600 modified oils. Comparing the products obtained with PEG-400 (PM0106 and PM0120) the hydroxyl index was slightly lower for the reaction time equal to 3 h, suggesting a higher PEG consumption.

[049] As the PEG diester structure does not have hydroxyl in its structure, the hydroxyl index for oils modified with PEG-400 was lower. Thus, the reactions conducted with PEG-600 formed a lower concentration of glycerol, with the formation of PEG monoester prevailing, which is confirmed by the appearance (transparency) of the samples obtained with PEG-600. According to this study, the greater the PEG molar mass, the greater the monoester/diester ratio for the same fatty acid used.

[050] The pH of modified oils in 5% m/m solution in distilled water (95% distilled water and 5% modified oil) was analyzed for all experiments. Table 5 shows the results of the analyses, in which it is possible to note that the pH values of oils modified with PEG-600 are, on average, higher than those modified with PEG-400. This result is related to the predominance of PEG monoester in oils modified with PEG-600, in which the amount of hydroxyl causes the pH to be higher than the mixture containing predominantly PEG diester.

[051] According to the pH values obtained and gathered in table 5, the pH of the samples is close to the pH of PEGs in aqueous solution at 5% (m/v).
Table 5 - pH of modified oils in deionized water (5% m/m solution)

Example 2.2 – Fourier Transform Infrared Spectroscopy (FT-IR)

[052] The FT-IR analyzes were performed in order to identify the characteristic bands of palm kernel oil, PEGs and modified oils. Figures 5a and 5b show the FT-IR spectrum of palm kernel oil, PEG-400 and PEG-400 modified oils (PM0120 and PM0106). Figures 6a and 6b show the spectra of palm kernel oil, PEG-600 and PEG-600 modified oils (PM0118 and PM0108). As modified oils are formed by a mixture of molecules, it was not possible to identify specific peaks or bands comparing the spectrum of palm kernel oil and PEG, ie, all peaks present in the modified oils are present in palm kernel oil or in PEG . In the reaction in an acidic medium, the triglyceride is converted into diglyceride, monoglyceride and glycerol, followed by the release of the ester.

Example 2.3 - Surface tension and turbidity of the 5% solution (m/m)

[053] The surface tension of oils modified with PEG were analyzed and the results are represented in table 6. These results were treated statistically at the 95% confidence level. Thus, it is concluded that the modified oils, even with the differences in appearance, showed similarities in relation to surface tension due to the concentration of PEG employed in the reactions and to the mono and diesters of PEG formed.
Table 6 - Surface tension results of oils modified with PEG-600 and PEG-400

[054] The effect of the concentration of oils modified with PEG-600 (PM0108) and PEG-400 (PM0120) on the surface tension of deionized water was analyzed in order to verify the profile of the curve and the efficiency of the modified oils in reducing the surface tension of water. The results, shown in Figure 7, show the relationship between surface tension and the concentration of modified oils (PM0108 and PM0120). According to the results, the surface tension drop profile was very close among the oils analyzed, with the equilibrium being reached around 1.0 g/L. However, both modified oils have characteristics of nonionic surfactant, as a function of the concentration of PEG used in the reaction and as a function of the formation of PEG mono and diesters.

[055] To verify the effect of modified oils in relation to the solubility in water and the stability of the oil-in-water mixture, samples were diluted in deionized water (solution at 5% m/m) and evaluated for turbidity.

Turbidez da água deionizada = 5 NTU[056] The samples were analyzed by dissolving 5 g of the modified oil in 95 g of deionized water. Table 7 shows the turbidity results, in UNT, of the modified oil solutions. The smaller the UNT value, the greater the transparency of the sample. Considering that the turbidity of the water used in the dilution of modified oils is equal to 5 NT, the PM0111 and PM0119 oils were the ones that came closest to the turbidity of the water, especially the dilution carried out with the PM0111 oil. For this mixture, the turbidity obtained was equal to 9.9 UNT, which indicates that the PM0111 oil presented better performance in relation to transparency and stability, being indicated for the manufacture of translucent shampoos and soaps.
Table 7 - Turbidity results of modified oils dissolved in deionized water at a concentration equal to 5%

Turbidity of deionized water = 5 NTU

Example 2.4 - Viscosity

[057] In table 8, below, the results of the viscosity analysis of oils modified with PEG400 and PEG600 are shown. Oils modified with PEG-600 had the highest viscosity values, while oils modified with PEG-400 had the lowest. The difference in oil viscosity is related to the higher molar mass of PEG-600 and its consequent greater interaction with palm kernel oil.
Table 8 - Viscosity of oils modified with PEG-600 and PEG-400

[058] Figure 8 shows the behavior of complex viscosity as a function of temperature for palm kernel oil, PEG-600, a product of the mixture PM0107 without catalyst and the oil modified with PEG600 (PM0108). The viscosity behavior of the oil modified with PEG-600 (PM0108) was different from the other profiles presented, that is, with increasing temperature, the viscosity decreases in linear form and, later, more slowly to ~25.5°C, remaining practically stable after at higher temperatures.

[059] Such results are consistent with the fact that, in the presence of the catalyst, the reaction between the PEG and the oil effectively occurs, forming compounds that modified the solidification temperature of the oil thus modified. After 21 °C, the viscosity decreases sharply until reaching 35 mPa.s, at approximately 25.5 °C, remaining constant as the temperature decreases. The same behavior of viscosity can be verified for PEG-600 and for the PM0107 reaction without catalyst, that is, the viscosity decreases by ~23.5 °C for PEG-600 and ~19.5 °C for the PM0107 reaction until reaching 90 mPa.s and stabilized at this value after 25.5 °C. The viscosity behavior for the oil modified with PEG-600 (PM0108) was different, that is, with increasing temperature, the viscosity decreases linearly and more slowly up to ~25.5°C, remaining practically stable for higher temperature values.

[060] The comparison of viscosity results after the melting temperature shows that the viscosity of palm kernel oil is lower in relation to the viscosity of PEG-600, and of the product of reactions PM0107 and PM0108. Considering that the ratio of palm kernel oil to PEG is 1:3, the viscosity of the PM0107 and PM0108 products is related to the amount of PEG used and the analysis temperature. Increasing the temperature weakens the hydrogen bonds, decreasing the hydration of the ethylene oxide chain and, as a consequence, the fluidity, until the solidification point is reached.

Example 3 – Application of modified oils Application in shampoo

[061] The modified oils were applied in standard shampoo formulation to verify the effect of the oils in relation to the appearance (transparency), viscosity and stability of the final product. The efficiency of modified oils was tested in translucent shampoo formulations, using standard ingredients and quantities used in the cosmetic segment. For this, 15% ethoxylated sodium lauryl ether sulfate (2EO), 2% cocoamidopropyl betaine, 1% coconut fatty acid diethanolamide, 2.0 to 4.0% PEG-modified oil, and water were used. deionized (80 to 76%).

[062] The mixture was prepared with a mechanical stirrer at 150 rpm until complete homogenization and the pH was adjusted to the range of 5.5 to 6.5.

[063] Figures 9a and 9b show the appearance of the shampoo obtained with 4% by mass of palm kernel oil without modification, in which (a) it is the shampoo right after its preparation; and (b) is the shampoo after 15 days of rest at (23±2)°C. In these images, it is possible to verify the milky/opaque aspect of the shampoo immediately after its preparation and the presence of two phases after 15 days of rest, which indicates the instability of the system.

[064] Figures 10a, 10b, 11a and 11b show the aspects of shampoos prepared with 4% (w/w) of palm kernel oil modified with PEG-600 (PM0108) and with PEG-400 (PM0106) soon after preparation (a) and after 15 days of rest at a temperature of (23±2)°C (b). The analysis of the figures allows us to conclude that the aspects of the shampoos after preparation and after 15 days of rest are that of a translucent liquid and without phase separation, which indicates that the modified oils, with both PEG-400 and PEG- 600, have water solubility and compatibility with the components commonly used in this type of formulation.

[065] The viscosity of shampoos, one of the main marketing appeals in the cosmetic industry, was analyzed as a function of the concentration of NaCl. Concentrations between 2 and 4% by mass of the modified oil were used in the formulation of the shampoos submitted to the test. As can be seen in figure 12, there is an increase in the viscosity of shampoos as the NaCl concentration increases, followed by a decrease in viscosity after the saturation point of the medium. The saturation point can be obtained by inflection of the viscosity curve as a function of the sodium chloride concentration.

[066] The concentration of NaCl necessary to reach the saturation point for shampoos A, I, G and the standard was between 2.0% and 2.5%. However, the saturation point for shampoo D, prepared with 4% of the modified oil (PM0120) was equal to 1.0%, resulting in a sudden increase in viscosity.

[067] Considering that the PEG-400 molecule is smaller than the PEG-600 molecule, the repulsion forces between the charged molecules of the surfactants, by the addition of salt, is decreased in the formulation containing PEG-400, which generates a more efficient increase in viscosity. However, saturation also occurs more quickly, and this effect is only noticeable at higher concentrations (4% modified oil). For concentrations less than 4%, the size of the molecule has less interference with viscosity.

[068] Also in relation to Figure 12, it can be noted that there was no significant difference in the viscosity profile for 2% of modified oil (curves I and G) up to the saturation point, that is, regardless of the type of PEG used in oil modification, the viscosity behavior was similar. However, after the saturation point, the viscosity of shampoo I (PM0108) was lower (~230 mPa.s) when compared to the viscosity of shampoo G (~450 m.Pa.s). For the formulation prepared with 4% oil modified with PEG-600 (curve A), the thickening ability decreased dramatically.

Application in oil-in-water (O/W) emulsions

[069] To evaluate the emulsifying property of oils modified with PEG-400 and PEG-600, oil-in-water (O/W) emulsions were prepared employing 20% (m/m) of andiroba oil as oil/organic phase, 5% (m/m) of the modified oils (PM0118, PM0108, PM0116, PM0112, PM0106, PM0116, PM0120 and PM0122) and 75% (m/m) of deionized water. The emulsions used as control were prepared by replacing the modified oil with PEG-600 and PEG-400.

[070] The emulsions were prepared in a high pressure homogenizer (Art Peças, model Aplab-10). In a beaker, 75% (m/m) of water, 5% (m/m) of modified oil and 20% (m/m) of andiroba oil were added. The mixture was left under stirring for 1 minute at 150 rpm. The content (organic phase + aqueous phase) was transferred to a high pressure homogenizer, with pressure adjusted to 600 bar, where it remained for 3 minutes. During homogenization, the homogenizer reservoir (collector cup) was cooled with water to 2 °C to avoid heating.

[071] Table 9 brings together the results of the mean droplet diameters (Dg) and droplet size distributions (DTG) obtained after homogenization. Emulsions with diameters between 121 and 202 nm and low droplet size distribution were obtained in the presence of the oil modified with PEG-600. The diameters obtained for the emulsions prepared with PEG-600 and PEG-400 (control) were 493 and 590 nm, respectively, with a DTG equal to 0.18.

[072] It was not possible to obtain the diameters of the emulsions prepared with oils modified with PEG-400 due to phase separation soon after homogenization. Such results can be justified as a function of the degree of modification of the palm kernel oil and the molar mass of the PEG used. For nonionic polymeric stabilizers of low molar mass, there is less interaction of the polar groups with water, which favors the interaction with the oil or with the oil/water surface.
Table 9 - Mean droplet diameter (Dg) and droplet size distribution (DTG) of O/W emulsions

[073] Figure 13a shows the appearance and stability of emulsions prepared with oils modified with PEG-600 (PM0118, PM0108, PM0116 and PM0112) before the accelerated stability test and after stability in an oven at 40 °C, by 15 days. The same test, using the same proportions of andiroba oil and water, was carried out for the oils modified with PEG-400 (PM0106, PM0120, PM0113) before and after the oven stability test, carried out as described above.

[074] The solutions prepared with the modified oils emulsified and were stable for a period longer than 15 days, which is justified by the more polar structure of PEG-600 and the compounds formed in the oil modification reaction with PEG-600 - a mixture of mono, di and triglycerides, mono and diester of PEG – which are more polar and more miscible in water, which helps in the stability of the emulsions.

[075] The diameter and droplet size distribution of the emulsions produced with the oil modified with PEG-600 were smaller when compared with the diameter of the oil/water emulsion stabilized only with PEG-600 and PEG-400, as well as shown by the data gathered in table 8. These results show that the stability of emulsions containing andiroba oil, water and PEG-modified palm kernel oil is affected by the type of PEG used in the palm kernel oil modification step, which evidences and supports with the water solubility and turbidity results previously presented.

[076] It is to be understood that the present description does not limit application to the details described herein and that the invention is capable of other embodiments and of being practiced or performed in a variety of ways, within the scope of the claims. Although specific terms have been used, such terms should be interpreted in a generic and descriptive sense and not for the purpose of limitation.

Claims (10)

METHOD OF MODIFICATION OF VEGETABLE OILS characterized by direct transesterification using polyethylene glycol (PEG) and a catalyst, in which polyethylene glycol has a molar mass in the range of 400 to 600 g/mol and is used in a proportion of 1:35 to 1:2 in relation to vegetable oil; and the catalyst employed is an acid catalyst, employed at a concentration of 0.1% to 0.2%. METHOD, according to claim 1, characterized in that the catalyst is selected from the group comprising butylstannoic acid, 2-ethyl hexanoate tin (II, dibutyl tin oxide, modified dibutyl tin oxide and dibutyl tin dilaurate. METHOD, according to claims 1 or 2, characterized in that it is carried out at a temperature ranging from 200 °C to 300 °C, for a time of 1 to 5 h, under mechanical agitation. MODIFIED VEGETABLE OIL characterized by having a hydroxyl index in the range of 133.00 to 180.12 mgKOH/g and glycerol percentage in the range of 1.5 to 2.0. MODIFIED VEGETABLE OIL, according to claim 4, characterized by having a pH in the range of 4.68 to 6.37 in 5% solution (m/m) in deionized water. MODIFIED VEGETABLE OIL, according to claim 4 or 5, characterized in that it has a surface tension in the range of 30.0 to 31.7 dyn/cm in a 5% solution (m/m) in deionized water and a viscosity in the range of 60, 0 to 115.0 cPa.s. MODIFIED VEGETABLE OIL, according to any one of claims 4 to 6, characterized in that it has turbidity in the range of 9.9 to 432 UNT in 5% solution (m/m) in deionized water. USE OF MODIFIED VEGETABLE OIL as defined by any one of claims 4 to 7, characterized in that it is in the formulation of cosmetic products. USE OF MODIFIED VEGETABLE OIL, according to claim 8, characterized in that it is in the formulation of translucent shampoos and soaps. USE OF MODIFIED VEGETABLE OIL, according to claims 8 and 9, characterized in that it is used in the formulation of vegetable oil/water emulsions without the introduction of another emulsifier.

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