PROCESS FOR OBTAINING ISOAMYL ACETATE FROM FUSEL OIL FROM ALCOHOLIC DISTILLATION IN SUGAR AND ETHANOL PLANTS AND PRODUCT OBTAINED

Description

1 / 24 PROCESS FOR OBTAINING ISOAMYL ACETATE FROM FUSEL OIL FROM ALCOHOLIC DISTILLATION IN SUGAR AND ETHANOL PLANTS AND PRODUCT OBTAINED BRIEF DESCRIPTION

[001] This patent application concerns a "PROCESS FOR OBTAINING ISOAMYL ACETATE FROM FUSEL OIL FROM THE ALCOHOLIC DISTILLATION OF SUGAR AND ALCOHOL PLANTS AND THE PRODUCT OBTAINED," which refers to a process for obtaining isoamyl acetate from isoamyl alcohol present in fusel oil from the alcoholic distillation of an industrial sugar and alcohol plant. Fusel oil, due to its low commercial value, is still the subject of little study and has not aroused great economic interest in alcohol plants. However, this byproduct is rich in isoamyl alcohol, which can be converted into isoamyl acetate, a product that can be used in the fine chemical field for higher value-added products. FIELD OF APPLICATION

[002] The present invention falls within the field of Chemical Engineering and Bioprocesses, since it refers to the process of obtaining isoamyl acetate from fusel oil, a byproduct obtained from the fractional alcoholic distillation stage of an industrial sugar and alcohol plant. CONVINCING

[003] Biofuels represent a topic of great international importance due to the dependence on petroleum derivatives for energy production and its consequences on the planet's climate change. In this scenario, Brazil has an excellent opportunity to work on new energy matrices associated with the production of fuels and chemical products through renewable sources. Currently, large quantities of ethanol are produced from sugarcane sucrose. While new technologies are being implemented in the sugar-ethanol production system, Brazilian ethanol from Petition 870240109895, dated 12 / 24 / 2024, page 8 / 53 2 / 24 of sugarcane is increasingly consolidating itself as an excellent alternative to fossil fuels. An example of this is cellulosic ethanol (2G ethanol), which, through chemical and enzymatic processes, allows the hydrolysis of cellulosic chains into fermentable sugars. This makes it possible to produce ethanol from bagasse or sugarcane straw. Furthermore, the vinasse left by the distillery in this process is biodigested in bioreactors to produce methane gas, thus offsetting the deficit of sugarcane bagasse used for ethanol production that would otherwise be burned in boilers for energy cogeneration, using biomethane, another type of green fuel.

[004] In sugar and ethanol plants, several byproducts and process effluents are obtained in the sugar-ethanol production stages, such as sludge from juice decanters, vinasse, phlegm, excess yeast, fusel oil, among others. Fusel oil is a byproduct of alcoholic fermentation and consists of a mixture of higher alcohols, ethanol, water, and other components. Its commercial importance lies mainly in the presence of isoamyl alcohol, which is one of the substances used in the manufacture of esters, compounds relevant to the chemical industry that have high added value. The recovery of this higher alcohol is carried out through unit operations that exploit phase equilibrium, such as distillation and liquid-liquid separation.

[005] Fusel oil is a mixture of alcohols with molecular weights higher than ethanol that concentrates in a specific region of the rectification column during the distillation stage of the industrial bioethanol process and needs to be removed to prevent ethanol losses. Among the components of fusel oil, the one with the highest concentration is isoamyl alcohol or 3-methyl-1-butanol, reaching values ​​close to 40% (mass / mass). Most plants in Brazil add this byproduct to the hydrated ethanol produced because they do not have or are unaware of a way to reuse it, given its low commercial value.

[006] Within the scope of the concept presented, the present invention proposes to refine the isoamyl alcohol present in fusel oil, obtained in the distillation process. Petition 870240109895, dated 12 / 24 / 2024, page 9 / 53 3 / 24 of the fuel ethanol is used to produce isoamyl acetate, which is an ester with high added value. BACKGROUND OF THE INVENTION

[007] The purification of isoamyl alcohol from fusel oil, as well as its conversion to isoamyl acetate, is a poorly studied process; therefore, there are few prior art forms that resemble the present innovation.

[008] Among the records found, those that most closely resemble the present invention are detailed below, however, none of them specifically addresses the process of producing isoamyl acetate from fusel oil, and even those that have some similarity still present differences.

[009] The prior work FERREIRA, 2012 entitled “STUDY OF THE FUSEL OIL DISTILLATION PROCESS” is a master's thesis that aimed to study the industrial distillation process of fusel oil to obtain isoamyl alcohol using the Aspen Plus simulator. In a first stage, experiments were carried out in a pilot distillation column and the results obtained were compared with those simulated for the same process, indicating good agreement between the data. Subsequently, samples of fusel oil collected from fuel ethanol plants were analyzed by gas chromatography for the characterization of this mixture. Subsequently, an investigation of the phase equilibrium, Vapor-Liquid Equilibrium (VLE) and Liquid-Liquid Equilibrium (LLE), of the components involved in this mixture was carried out, and some parameters were adjusted.Preliminary studies of the binary water / isoamyl alcohol mixture and the ternary water / isoamyl alcohol / ethanol mixture were carried out, providing the basis for the proposed configurations for the multicomponent system. Using experimental design tools, operational and construction parameters were defined for the two proposed configurations. Two new feed compositions were tested, allowing the development of a final fusel oil purification plant. This configuration resulted in a 99.52% recovery of isoamyl alcohol and a total steam consumption of 0.8311 kg per kg of fusel oil. Petition 870240109895, dated 12 / 24 / 2024, page 10 / 53 4 / 24 of product containing the isomers isoamyl alcohol (81.80% w / w) and active amyl alcohol (17.81% w / w).

[0010] The prior art cited above is the one that most closely resembles the present patent application. In the prior art, examples of fusel oil distillation are presented, including a process in which fusel oil is treated with NaOH and subjected to a decantation step, in which an aqueous phase and an organic phase are formed. The organic phase is subsequently subjected to distillation, with more than one distillation step being performed to obtain isoamyl alcohol. Later, the document explains that isoamyl alcohol is used in the preparation of isoamyl acetate, an application of great value to the market.

[0011] The prior work GÜVENÇ et al., 2006 entitled “ENZYMATIC ESTERIFICATION OF ISOAMYL ALCOHOL OBTAINED FROM FUSEL OIL: OPTIMIZATION BY RESPONSE SURFACE METHODOLOGY” deals with the optimization of lipase-catalyzed isoamyl acetate production, of industrial importance, carried out using response surface methodology (RSM). Isoamyl alcohol, distilled from fusel oil, and acetic acid were used as substrates. Immobilized lipase from Candida antarctica (Novozym 435) was used as a catalyst for this reaction in a solvent-free system. RSM, based on a five-level, four-variable central composite rotatable design, was used to evaluate the effects of important parameters on isoamyl acetate production. The parameters are acid / alcohol molar ratio (0.2 - 0.8), amount of enzyme (4 - 12%, w / w), temperature (30 - 50 °C) and reaction time (4 - 8 h).It was found that the most effective parameter was the acid / alcohol molar ratio. The model indicated the ideal conditions for maximum esterification (4.4 mmol of ester / g of mixture), with an acid / alcohol molar ratio of 0.8, 12% (w / w) enzyme at 30 °C, after 8 hours, which was in good agreement with the experimental value. The coefficient of determination (R²) for the model is 0.9968. The probability value (P < 0.0001) demonstrates very high significance for the regression model. Petition 870240109895, dated 12 / 24 / 2024, p. 11 / 53 5 / 24

[0012] The document discloses a process for distilling fusel oil to obtain isoamyl alcohol, comprising distillation in a Vigreux column, in which fractions with a boiling point above 117 °C were collected and subjected to a subsequent distillation step to obtain isoamyl alcohol. The isoamyl alcohol thus obtained is subsequently subjected to an enzymatic esterification process to obtain isoamyl acetate. Before the distillation step, the fusel oil is subjected to a treatment to remove water.

[0013] The prior art PI 8505255- 8 B1 entitled “IMPROVED CONTINUOUS FRACTIONATION PROCESS OF A STREAM OF ALCOHOL DISTILLERY BY-PRODUCTS” deals with a continuous fractionation process of a stream of alcohol distillery by-products, called fusel oil, containing alcohols with 2 to 5 carbon atoms, characterized by comprising the steps of optional caustic treatment of the fusel oil; optional separation of the treated fusel oil into two liquid fractions, one organic and one aqueous, by means of decantation, and continuous distillation with lateral removal of the aqueous fraction, with lateral removal of the iso-pentyl alcohol product in the vapor or liquid phase, and with removal of bottom residues mixed with iso-pentyl alcohol.The process also includes the recovery of organics from the aqueous phases of the settling tanks, the use of the bottom residue mixed with at least part of the distillate (lighters) as a byproduct fuel, and the use of the remaining distillate as fuel or as products, after fractionation into its components.

[0014] The previous work FERREIRA et al., 2019 entitled “YIELD IN THE SYNTHESIS OF ISOAMYL ACETATE” describes the importance of biofuels in the Brazilian economy. Attention was given to obtaining ethanol from sugarcane. The ethanol production process generates several products and byproducts, mainly fusel oil, which became a tool for study because a distillation process is used to extract isoamyl alcohol, which is of great importance in various industrial sectors such as food, chemical, and pharmaceutical. The objective of this Petition 870240109895, dated 12 / 24 / 2024, page 12 / 53 The objective of this study is to obtain the yield in the synthesis of isoamyl acetate, a compound used as an artificial flavoring with a characteristic banana odor in the food industry. Isoamyl acetate is the result of an esterification reaction, generally obtained by homogeneous catalysis using concentrated sulfuric acid. Knowing that it is a reversible reaction, Le Chatelier's principle was applied, maintaining an excess of acetic acid. The experimental results confirm that the temperature, reflux time, and amount of reagents are directly related to the yield. Three experiments were conducted to obtain the yield of isoamyl acetate, which were: 36.19%, 52.68%, and 72.19%, the latter being the most significant, which can be an indicator for selecting the methodology used for the production of the substance.

[0015] This document discloses the production of isoamyl acetate by reacting isoamyl alcohol with acetic acid, using H2SO4 as a catalyst. After isolation, the isoamyl acetate is distilled. Regarding novelty, compared to prior art, no document was found that specifically discloses a process comprising all the claimed steps, whatever they may be.

[0016] The prior art BR102014032357-0, entitled “SYSTEM AND PROCESS FOR RECOVERY OF ISOAMYL ALCOHOL, ETHANOL AND BUTANOL AND PRODUCTS THUS OBTAINED”, describes an integrated system for the production of isoamyl alcohol, which is a raw material for different types of products in industry, such as reagents and solvents for the food industry, paints, varnishes, plasticizers and perfumery, in addition to the recovery of ethanol in the distillation process of fermented wine, resulting in a reduction in waste generation. This integrated system and processes described in the invention have applications in the beverage industry and in ethanol production plants and distilleries, guaranteeing the quality and purity of the final product and increasing the efficiency of the production process.

[0017] The integrated process is characterized by the following steps: Conventional production of hydrated ethanol, without alteration to existing facilities; Petition 870240109895, dated 12 / 24 / 2024, page 13 / 53 7 / 24 Removal of fusel oil from ethanol distilleries; Concentration and decantation of the removed fusel oil with the addition of water; Phase separation: aqueous phase, which returns to the distillery, and organic phase, which is processed in the fusel oil distillation unit; Extraction of isoamyl alcohol at the base of the fusel oil distillation column; Recycling of the top product to the hydrated ethanol distillery, resulting in increased efficiency and purity of the ethanol obtained. The product obtained as hydrated ethanol has a recovery of 99.4% and a purity of 93.3%, and the isoamyl alcohol and active amyl alcohol have a purity of 99.6% and a recovery equivalent to 99.8% (% mass / mass).

[0018] Prior art PI0306043-8, entitled “AZEOTROPIC WATER REMOVAL PROCESS FROM SELF-GENERATED ESTERS BY ESTERIFICATION OF SUGAR CANE AND SIMILAR FUSEL OILS” The study presents a method for transforming fusel oil into a mixture of esters derived from the alcohols present, which can be subsequently separated into pure and valuable components by simple physical methods. The esters obtained from the esterification of the five predominant alcohols in fusel oil, ethanol, propanol, butanol, isobutanol and isoamyl alcohol, have wide industrial application and are produced in large quantities.

[0019] The process begins with the distillation of fusel oil after the addition of a carboxylic acid and a catalyst, such as sulfuric acid. The mixture is heated until distillation begins, at which point an azeotropic mixture of water and esters is extracted. As the distillate accumulates, separation into two phases occurs: an aqueous phase and an organic phase, rich in esters, which returns to the reactor, while the aqueous phase is collected for treatment and reuse, if necessary.

[0020] When the formation of esterification water ceases and water separation is complete, most of the esters are distilled, retaining enough residue to prevent smoke generation. This residue, which contains the catalyst and significant amounts of isoamyl acetate, is reused several times to reduce consumption of both. The distillate, now free of alcohols and with small amounts of Petition 870240109895, dated 12 / 24 / 2024, p. 14 / 53 8 / 24 of the carboxylic acid is washed with a sodium bicarbonate solution to neutralize residual acidity. The distillate is then fractionated in a fractionation column, allowing the production of high-purity esters. Quantitative experimental assays were performed for the production of butyrates, demonstrating the viability of the process under productive conditions.

[0021] The prior art BR 112020013655-7, entitled “CATALYTIC PROCESSES FOR CONVERTING REFINED MIXTURES OF CRUDE AND / OR REFINED FUSEL OIL INTO HIGHER VALUE RENEWABLE CHEMICAL PRODUCTS BY MEANS OF MIXED METAL OXIDE OR ZEOLITE CATALYSTS” deals with catalytic methods that aim to improve mixtures of fusel oils, both crude and refined, transforming them into higher value-added renewable chemical products.

[0022] This document presents techniques for subjecting vaporized fusel oil streams to different catalysts, including mixed metal oxides, metal- or non-metal doped zeolites, and metal oxides. These approaches offer alternatives for adding value to fusel oil blends, resulting in renewable chemicals such as methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK), isoamylene, and isoprene. OBJECTIVE OF THE INVENTION

[0023] The present patent application aims to provide a technically feasible process for the production of isoamyl acetate from fusel oil obtained from a sugar and ethanol plant integrated with a hydrated fuel ethanol distillery. OF THE INVENTION

[0024] The present invention relates to a process for obtaining isoamyl acetate from isoamyl alcohol present in fusel oil derived from the alcoholic distillation of an industrial sugar and ethanol plant. The purification of isoamyl alcohol is carried out through unit operations that exploit phase equilibrium, such as decantation, distillation, and liquid-liquid separation. The refined isoamyl alcohol is converted into isoamyl acetate through a chemical reaction. Petition 870240109895, dated 12 / 24 / 2024, page 15 / 53 9 / 24 under reflux catalyzed with sulfuric acid. The isoamyl acetate obtained is mixed with water under stirring for homogenization and phase separation. The aqueous phase (denser in the system) is extracted from the bottom of the separatory funnel, carrying with it the compounds that dissolved in this phase, leaving only the organic phase (rich in isoamyl acetate) in the funnel.

[0025] The technology solves the problem of disposing of a residue obtained in the fractional alcoholic distillation stage of an industrial ethanol production plant, called fusel oil, and because it does not have high commercial value, it is still the subject of little study and has not aroused great economic interest in sugar and ethanol plants. However, this residue is rich in isoamyl alcohol, which can be converted into isoamyl acetate.

[0026] The refining of isoamyl alcohol from fusel oil, as well as its conversion into isoamyl acetate, is a poorly studied process, which corroborates the inventiveness of the present invention. The isoamyl acetate produced can be used in the fine chemicals sector (pharmaceutical, food, among others) for the production of higher value-added products. In this way, in addition to not accumulating a "residue" in the factory, the company can increase its production efficiency of other bioproducts of commercial interest. ADVANTAGES OF THE INVENTION

[0027] The main technical advantages provided by the present invention are: • To solve the technical problem related to the disposal of a residue obtained in the fractional alcoholic distillation stage of an industrial ethanol production plant, fusel oil, which, due to its low commercial value, is still the subject of little study and does not arouse great economic interest in sugar and ethanol plants; however, the residue is rich in isoamyl alcohol, which can be converted into isoamyl acetate; • To make isoamyl acetate available, with the potential to be used in the fine chemicals sector (pharmaceutical, food, among others) for the production of higher value-added products. Therefore, in addition to not accumulating a "waste" Petition 870240109895, dated 12 / 24 / 2024, page 16 / 53 With 10 / 24 hours of operation at the factory, the company could see an increase in its production efficiency for other bioproducts of commercial interest. DESCRIPTION OF THE FIGURES

[0028] In order to provide a better understanding of the present invention, reference will be made to the figures described below: • FIG. 1 shows the general flowchart of the process steps of the invention. Where, 1 refers to fusel oil removed from the distillery; 2 water + sodium bicarbonate stream; 3 water and light alcohols and water stream for distillation; 4 concentrated fusel oil stream; 5 saturated steam stream (10 bar(g)); 6 reflux stream from the column; 7 feed stream to the decanter; 8 organic reflux stream to the column; 9 aqueous phase for isoamyl alcohol stripping column; 10 isobutanol, light alcohols and water; 11 isoamyl alcohol stream; 12 acetic acid stream; 13 sulfuric acid stream (catalyst); 14 reflux of the aqueous phase; 15 reflux of the organic phase; 16 feed to the isoamyl acetate separation column; 17 stripping column; 18 Saturated vapor (10 bar(g)); 19 Reflux of the organic phase; 20 Saturated vapor (10 bar(g)); 21 Isoamyl acetate; 22 Purge of the isoamyl alcohol separation column;23 aqueous phase for acetic acid stripping column; 24 water for condensation and cooling; 25 water for condensation and cooling; 26 water for condensation and cooling; 27 purge of the esterification column; 28 purge of the isoamyl acetate separation column. It consists of the following equipment: A fusel oil concentrator; B isoamyl alcohol distillation column; C reboiler of column B; D condenser / cooler; E decanter; F esterification column; G condenser / cooler; H decanter; I reboiler of column F; J isoamyl acetate column; K decanter; L condenser / cooler; and finally, M reboiler of column J. • FIG. 2 shows a schematic representation of the fractional distillation of fusel oil on a laboratory bench. Petition 870240109895, dated 12 / 24 / 2024, page 17 / 53 11 / 24 • FIG. 3 shows a photo of a fractional distillation system for fusel oil on a laboratory bench. • FIG. 4 shows a schematic representation of the reflux evaporation system used to synthesize isoamyl acetate (Fischer esterification). • FIG. 5 shows a photo of the reflux evaporation system used to synthesize isoamyl acetate (Fischer esterification). • FIG. 6 shows a photo of how the organic phase separates from the aqueous phase inside the separatory funnel, allowing the separation of isoamyl acetate. • FIG. 7 shows a photograph of the fractional distillation system for separating isoamyl acetate. DETAILED DESCRIPTION

[0029] The present invention relates to a process for obtaining isoamyl acetate from isoamyl alcohol derived from fusel oil from a fuel ethanol production plant, comprising the following steps, as shown in FIG. 1: a. Pre-refine fusel oil obtained from an industrial ethanol plant at a sugar and ethanol mill; b. Refine isoamyl alcohol derived from pre-refined fusel oil and estimate the yields of this process; c. Synthesize isoamyl acetate from the isoamyl alcohol obtained previously; d. Refine the isoamyl acetate obtained previously and estimate its production yields.

[0030] Initially, the isoamyl alcohol derived from fusel oil is refined. To this end, samples of fusel oil are collected and stored in the laboratory. The first procedure performed consists of pre-refining the oil to eliminate water and water-soluble compounds, since each plant uses a different proportion of fusel oil and water in the decanter, as well as different temperatures at this stage of the process. The objective of this stage is to simulate a step Petition 870240109895, dated 12 / 24 / 2024, page 18 / 53 12 / 24 extraction of water-soluble components, eliminating as much water and water-soluble compounds as possible from the samples. Therefore, yield analyses and results are subsequently calculated on pre-refined fusel oil samples.

[0031] Thus, 400 mL of fusel oil and 133 mL of saturated sodium bicarbonate solution are placed in a separatory funnel, where the system is mechanically shaken and left to stand until the phases completely separate to extract the organic phase. The aqueous phase is discarded and this procedure is repeated with the organic phase obtained.

[0032] After the second stage of decantation and removal of the aqueous phase, 5 g of anhydrous sodium sulfate are added to the organic phase and this solution is filtered through filter paper to remove the sodium sulfate along with any residual extracted water.

[0033] Pre-refined fusel oil is placed in a 500 mL round-bottom flask and subjected to fractional distillation using a thermometer, a Liebig condenser, a Vigreux column, and beakers for collecting the product fractions. The boiling point of isoamyl alcohol at this pressure is approximately 129 °C. The heating mantle temperature is set to 150-160 °C. The distillation occurs in two stages, the first to obtain components with boiling points close to 129 °C and a second to obtain isoamyl alcohol with higher purity. In the first distillation, the refined fusel oil fractions with boiling points between 125 and 132 °C are collected. This distillate is reintroduced into the distillation system, and this time three fractions of distilled product are collected at different temperature ranges, designated samples A, B, and C, as shown in Table 1 below (FIG. 2 and FIG. 3). Samples Collection temperature (°C) A 125 - 127 B 127 - 129 C 129 - 132 Petition 870240109895, dated 12 / 24 / 2024, page 19 / 53 13 / 24 Table 1: Fractionation temperature range for the second distillation of refined fusel oil.

[0034] Subsequently, isoamyl acetate is synthesized from isoamyl alcohol obtained in the previous step. For this purpose, refined isoamyl alcohol, glacial acetic acid, and sulfuric acid are used as catalysts. Excess acetic acid is used to shift the chemical equilibrium of the reaction towards the product of interest, in order to hinder the reverse reaction from occurring. In a 100 mL round-bottom flask, 30 mL of the sample rich in isoamyl alcohol obtained in the previous step, 35 mL of glacial acetic acid, and 1 mL of sulfuric acid are added. Glass beads are added to the bottom of the flask, and then the flask is heated using a heating mantle and kept under reflux for 30-60 minutes (FIG. 4 and FIG. 5).

[0035] After 30-60 min under reflux, the system is stopped by turning off the heat source, keeping the cooling water flowing through the condenser until evaporation has completely ceased. The flask is carefully removed from the heating mantle and left to stand until the mixture temperature reaches equilibrium with the environment. All the material contained in the round-bottom flask is transferred to a separatory funnel. 50 mL of distilled water is added to the sample and the system is shaken until the medium is homogeneous. After homogenization, the phases separate, since isoamyl acetate, as well as isoamyl alcohol, are characterized by low solubility in water. The aqueous phase (denser in the system) is extracted from the bottom of the separatory funnel, carrying with it the compounds that dissolved in this phase.

[0036] The organic phase is kept in the separatory funnel. After this, the following step is repeated twice: Add 25 mL of saturated sodium bicarbonate solution to the organic phase to neutralize the medium, since the reaction medium is prepared with excess acetic acid and sulfuric acid as a catalyst. The system is shaken to homogenize the mixture, and again the aqueous phase is extracted from the bottom of the funnel, leaving only the organic phase (rich in acetate) in the funnel. Petition 870240109895, dated 12 / 24 / 2024, page 20 / 53 14 / 24 of isoamyl) (FIG. 6). Subsequently, the organic phase is transferred to a 50 mL beaker and 1 to 3 grams of anhydrous sodium sulfate are added to remove residual water. Then, the mixture is filtered through filter paper and the resulting solution is prepared for fractional distillation in a Vigreux column.

[0037] Subsequently, the isoamyl acetate obtained previously is refined, requiring distillation of the mixture (FIG. 7). Thus, 40 mL of the organic phase obtained after the liquid-liquid separation steps is added to a round-bottom flask. The mixture has a boiling point of approximately 125 °C; therefore, gas chromatography data are collected only for the fraction that evaporates between 136 and 142 °C.

[0038] The examples presented here are intended only to illustrate one of the numerous ways of carrying out the invention, however, without limiting its scope. The fusel oil samples collected at the plants were analyzed by GC, and their respective concentrations of the main components were calculated and presented in Table 2. As described previously, a pre-refining step of the fusel oil was carried out to eliminate water-soluble compounds, since in each plant the fusel oil decantation step is carried out under different process conditions. Compounds Concentration (gL-1) Plant 1 Plant 2 Plant 3 Methanol 6.4 (27.4) 4.5 (8.2) 3.2 (9.1) Ethanol 27.8 (61.1) 22.1 (99.6) 19.6 (81.0) n-propanol 28.2 (22.7) 29.5 (29.4) 29.0 (27.3) Isobutanol 93.2 (72.0) 73.4 (71.0) 78.3 (73.0) Isoamyl alcohol 388.5 (320.4) 385.1 (373.2) 394.8 (371.2) Isoamyl acetate 2.9 (3.1) 2.9 (3.3) 2.8 (3,21) Table 2: Concentrations of alcohols present in fusel oil samples. *The values ​​in parentheses refer to the alcohol content of the original fusel oil before the pre-refining process. Petition 870240109895, dated 12 / 24 / 2024, p. 21 / 53 15 / 24

[0039] The results in Table 2 show that the concentrations of methanol and ethanol were decreased by approximately 76.5% and 54.5%, respectively; however, the concentration of isoamyl alcohol increased by 20% (compared to the alcohol content of the original fusel oil without pre-refining). The other alcohols remained at similar concentrations after the fusel oil pre-refining process. The fusel oil pre-refining process resulted in the elimination of water-soluble compounds and consequently promoted an increase in the concentration of isoamyl alcohol; therefore, the pre-refining step was successfully carried out.

[0040] Using the densities obtained for the fusel oil and pre-refined fusel oil samples (Table 2), the percentage of isoamyl alcohol and the mass of isoamyl alcohol in these samples were quantified, respectively. The values ​​are presented in Table 3. Fusel Oil Volume (mL) Density (gL-1) Isoamyl Alcohol (%m / m) Isoamyl Alcohol (g) Plant 1 400 851.0 37.6 128.2 Plant 2 400 829.1 45.0 149.3 Plant 3 400 847.0 43.8 148.5 Refined Fusel Oil Volume (mL) Density (gL-1) Isoamyl Alcohol (%m / m) Isoamyl Alcohol (g) 307 850.3 45.7 119.3 382 823.7 46.7 147.1 369 846.2 46.6 145.7 Table 3: Percentage and mass of isoamyl alcohol in pre-refined fusel oil samples. Petition 870240109895, dated 12 / 24 / 2024, page 22 / 53 16 / 24

[0041] Table 4 shows the volumes obtained after the first distillation of pre-refined fusel oil, with the collected fractions that distilled up to 125 °C, between 125 and 132 °C, and the remaining volume that did not distill up to 132 °C, i.e., remained in the volumetric flask. Refined fusel oil distillate (mL) Distilled volume (up to 125 °C) (mL) Distilled volume (125 °C to 132 °C) (mL) Bottom of volumetric flask (>132 °C) (mL) Plant 1 307.0 153.6 141.9 11.4 Plant 2 382.0 203.0 168.3 10.6 Plant 3 369.0 181.5 166.4 20.9 Table 4: Volumes obtained in the first distillation of pre-refined fusel oil.

[0042] The product of interest, obtained after the first distillation, with temperatures between 125 and 132 °C, was collected and subjected to a second fractional distillation, in order to obtain fractions with higher concentrations of isoamyl alcohol. In this second fractional distillation, the distilled products were classified as follows: samples: A, B and C, as shown in Table 1. Table 5 presents the results obtained for each of the samples and their respective collection temperature ranges. Initial Volume (mL) Initial Mass (g) Sample Temperature Range Volume (mL) Mass (g) Density (gL-1) pH Mill 1 141.9 114.9 Sample A 125 - 127 °C 37.0 30.1 815.6 6.9 Petition 870240109895, dated 12 / 24 / 2024, page 23 / 53 17 / 24 Sample B 127 - 129 °C 83.1 67.0 805.8 6.8 Sample C 129 - 132 °C 21.9 17.8 813.9 6.9 Usin a 2 168.3 134.3 Sample A 125 - 127 °C 59.7 48.8 817.7 7.0 Sample B 127 - 129 °C 86.1 69.2 804.0 7.1 Sample C 129 - 132 °C 20.0 16.3 813.8 6.9 Usin a 3 166.4 132.5 Sample A 125 - 127 °C 53.6 43.9 819.4 6.9 Sample B 127 - 129 °C 87.3 71.0 812.9 7.0 Sample C 129 - 132 °C 21.6 17.6 816.7 7.0 Table 5: Results obtained from the second distillation of the pre-refining oil, by temperature range.

[0043] Samples A, B, and C from each plant were also analyzed by gas chromatography (GC), and the concentrations of the components were calculated. Using the density value of each sample, the percentage of each component in each of the samples from each plant was also obtained. The results are presented in Table 6. Sample A Sample B Sample C Component Plant 1 Plant 2 Plant 3 Plant 1 Plant 2 Plant 3 Plant 1 Plant 2 Plant 3 Ethanol (gL-1) 8.1 1.6 1.6<lo q <loq <lo qPetition 870240109895, dated 12 / 24 / 2024, page 24 / 53 18 / 24 n-Propyl alcohol (g.L⁻¹) 32.1 11.9 12.9 5.5 0.9 4.0 <lo q <lo acetato de isoamila (g.l-1 4,9 <loq 3,6 3,8 4,0 4,5 3,9 4,1 álcool isobutílico (g.l·’) 142,3 110,3 128,3 65,3 36,7 58,7 6,9 4,2 6,6 isoamílico 557,4 623,1 675,4 730,3 729,2 745,6 733,2 708,2 762,2 densidade 815,6 817,7 819,4 805,8 804,0 812,9 813,9 813,8 816,7 etanol (%) 1,0 0,2 n-propanol 1,5 1,6 0,7 0,1 0,5 0,6 0,5% isobutanol 17,4 13,5 15,7 8,1 4,6 7,2 0,9 0,8 68,3 76,2 82,4 90,6 90,7 91,7 90,1 87,0 93,3 outros 9 8 4 12 5Table 6: Concentrations and mass percentages of components in distilled samples of pre-refined fusel oil. Petition 870240109895, dated 12 / 24 / 2024, page 25 / 53 19 / 24

[0044] With the calculated concentrations, densities, and masses obtained for each sample, the refining yield of isoamyl alcohol was calculated in relation to the sample collected at the plant and in relation to fusel oil. The results are presented in Table 7. Component Plant 1 Plant 2 Plant 3 Mass of fusel oil (g) 340.4 331.6 338.8 Mass of isoamyl alcohol in fusel oil (g) 128.2 149.3 148.5 Mass percentage of isoamyl alcohol in fusel oil (%) 37.7 45.0 43.8 Mass of pre-refined fusel oil (g) 261.0 314.6 312.3 Isoamyl alcohol in pre-refined fusel oil (g) 119.3 147.1 145.7 Mass percentage of isoamyl alcohol in pre-refined fusel oil (%) 45.7 46.7 46.6 Sample ABCABCABC Mass of each fraction (g) 30.1 67.0 17.8 48.8 69.2 16.3 43.9 71.0 17.6 Total mass (A+B+C) (g) 114.9 134.3 1 32.5 Isoamyl mass per distilled sample (g) 20.6 60.7 16.0 37.2 62.8 14.2 36.2 65.1 16.5 Mass percentage of isoamyl alcohol per range (%) 68.3 90.6 90.1 76.2 90.7 87.0 82.4 91.7 93.3 Petition 870240109895, dated 12 / 24 / 2024, page 26 / 53 20 / 24 Total mass of isoamyl alcohol (A+B+C) (g) 97.3 114.1 117.8 Mass yield of isoamyl alcohol purification relative to fusel oil (%) 75.9 76.5 79.3 Mass yield of isoamyl alcohol purification relative to pre-refined fusel oil (%) 81.6 77.6 80.8 Mass percentage of isoamyl alcohol relative to pre-refined fusel oil (%) 37.3 36.3 37.7 Table 7: Masses, percentages and purification yields of isoamyl alcohol from fusel oil.

[0045] The results obtained in Table 7 indicate that the isoamyl alcohol refining procedure was efficient and reinforces the importance of a fusel oil pre-refining step, since in an industrial process, the effluent from the fusel oil pre-refining process (wash water or weak water) is returned to the mobile fermentation tank and joins the wine that is fed back into the distillery.

[0046] In a continuous industrial-scale distillation process, it is expected that yields higher than those found in Table 7 and isoamyl alcohol concentrations close to those of samples B will be obtained, i.e., around 91% (m / m), since the product is withdrawn continuously, in the region of the column that is exactly at the temperature of interest, without cross-contamination and with lower process losses, and for this reason, these were the samples selected for the isoamyl acetate synthesis process. Petition 870240109895, dated 12 / 24 / 2024, page 27 / 53 21 / 24

[0047] Finally, during the first fractional distillation, the formation of a precipitate in the volumetric flask was observed in the laboratory, resembling some type of oil or grease. In the gas chromatography (GC) chromatograms of the last collected portions of refined isoamyl alcohol (samples C), small peaks were also observed after the peak of the isoamyl alcohol. These small peaks, as well as the precipitate formed in the flask, are probably related to alcohols with chains longer than 5 carbons, which have very low concentrations in the composition of fusel oil and were not identified in this invention.

[0048] For each of the isoamyl acetate synthesis reactions, carried out with 30 mL of samples rich in isoamyl alcohol (sample B), the samples described in this invention as samples D were obtained after the last fractional distillation, with the quantitative results presented in Table 8. Sample D Volume (mL) Density (gL-1) Mass (g) Plant 1 36.7 868.5 31.9 Plant 2 38.2 879.5 33.6 Plant 3 38.0 875.0 33.3 Table 8: Quantification of synthesized isoamyl acetate samples.

[0049] These samples were subjected to gas chromatography analysis to determine the concentrations of isoamyl acetate and other components present, and the results are presented in Table 9. Component Plant 1 Plant 2 Plant 3 Ethyl alcohol (gL-1) <lqo <lqo 2,3 acetato de isobutila (g.l-1) 11,2 21,8 62,1 álcool isobutílico 0,8 1,6 3,0 isoamílico 27,1 17,6 38,1Petition 870240109895, dated 12 / 24 / 2024, page 28 / 53 22 / 24 Isoamyl Acetate (gL-1) 550.4 519.3 502.2 Density (gL-1) 868.5 879.5 875.0 Ethyl Alcohol (%) <lqo <lqo 0,3 acetato de isobutila (%) 1,3 2,5 7,1 álcool isobutílico 0,1 0,2 isoamílico 3,1 2,0 4,4 isoamila 63,4 59,0 57,4Table 9: Concentration and mass percentage of components in isoamyl acetate samples (samples D). <lqo = valor inferior ao limite de quantificação.

[0050] According to the stoichiometry of the esterification reaction, with isoamyl alcohol as the limiting reagent, for every 1 gram of isoamyl alcohol consumed, approximately 1.477 grams of isoamyl acetate are formed. From the concentrations of isoamyl acetate and isoamyl alcohol (determined in the refined isoamyl alcohol samples), and the stoichiometric balance, the yield of the isoamyl acetate synthesis was then calculated, and the values ​​are presented in Table 10. Sample B - Refined isoamyl alcohol Sample D - Isoamyl acetate Volume (mL) Mass (g) Isoamyl Alcohol (g) Volume (mL) Mass (g) Isoamyl Acetate (g) Isoamyl Acetate (%) Stoichiometry (g) Yield (%) Plant 1 30.0 24.2 21.9 36.7 31.9 20.2 63.4 32.4 62.5 Petition 870240109895, dated 12 / 24 / 2024, page 29 / 53 23 / 24 Plant 2 30.0 24.1 21.9 38.2 33.6 19.8 59.8 32.3 61.4 Plant 3 30.0 24.4 22.4 38.0 33.3 19.1 57.4 33.0 57.8 Table 10: Masses, percentages, and mass yield of isoamyl acetate synthesis.

[0051] Based on these data, the amount of isoamyl acetate that can be produced for every 100 grams of pre-refined fusel oil was estimated by linear extrapolation, using the isoamyl alcohol concentrations obtained in each of the samples (A, B, and C) from each plant and the yield of the isoamyl acetate synthesis process. The values ​​are presented below in Table 11. Refined fusel oil (g) Refined isoamyl alcohol (%) Isoamyl acetate produced (g) Isoamyl acetate synthesis yield (%) Plant 1 100.0 37.3 23.3 62.5 Plant 2 100.0 36.4 22.3 61.4 Plant 3 100.0 37.7 21.8 57.8 Table 1 1: Isoamyl acetate production per 100 grams of refined fusel oil.

[0052] The approximate yield of isoamyl acetate from refined isoamyl alcohol is 60.6% (w / w), a result similar to that reported in the literature, due to the equilibrium of the chemical reaction. Finally, considering the percentage Petition 870240109895, dated 12 / 24 / 2024, page 30 / 53 Using a 24 / 24 ratio of isoamyl alcohol obtained from pre-refined fusel oil and the esterification reaction yield, we obtained an average overall yield of 22.5% (mass / mass) of isoamyl acetate, meaning that for every 100 grams of refined fusel oil, it is possible to synthesize approximately 22.5 grams of isoamyl acetate. Petition 870240109895, dated 12 / 24 / 2024, page 31 / 53< / lqo> < / lqo> < / lqo> < / lo> < / lo>

Claims

1 / 2 CLAIMS 1. PROCESS FOR OBTAINING ISOAMYL ACETATE FROM FUSEL OIL FROM THE ALCOHOLIC DISTILLATION OF SUGAR AND ALCOHOL PLANTS, characterized by comprising the steps of: a) Pre-refining of fusel oil obtained from an industrial ethanol plant of a sugar and alcohol mill, using fusel oil and saturated sodium bicarbonate solution in a volumetric ratio of 3:1; b) Refining of isoamyl alcohol from pre-refined fusel oil obtained in the previous step (a), collecting the fractions of pre-refined fusel oil with a boiling point between 125 and 132 °C; c) Synthesis of isoamyl acetate from isoamyl alcohol obtained in the previous step (b), excess glacial acetic acid and sulfuric acid as a catalyst for the synthesis of isoamyl acetate, in a volumetric ratio of 1:1.1:0.03 for refined isoamyl alcohol, glacial acetic acid and sulfuric acid, respectively, with the system under reflux for 3060 min;d) Refining of isoamyl acetate obtained in the previous step (c), in a volumetric ratio of 1:1 to the liquid obtained in step “c” and water, respectively, separating the organic phase from the aqueous phase.

2. PROCESS FOR OBTAINING ISOAMYL ACETATE, according to claim 1, characterized in that, in step “b”, the first distillate obtained is reintroduced into the distillation system, this time collecting three fractions of distilled product at different temperature ranges, as follows: A (125-127°C), B (127-129°C) and C (129-132°C).

3. PROCESS FOR OBTAINING ISOAMYL ACETATE, according to claim 1, characterized in that, in step “d”, 25-50 mL of saturated sodium bicarbonate solution is added to the total organic phase obtained, the organic phase being separated from the aqueous phase and 1-3 g of anhydrous sodium sulfate being added, and then recovered again by filtration.

4. PROCESS FOR OBTAINING ISOAMYL ACETATE, according to claim 1, characterized in that, in step “d”, the organic phase is distilled and the fraction with a boiling point between 136 and 142 °C is collected.

5. ISOAMYL ACETATE, obtained as described in claims 1-4, characterized by being obtained from fusel oil derived from the alcoholic distillation of sugar and ethanol plants.

6. USE OF ISOAMYL ACETATE, defined according to claim 5, characterized by being for the production of pharmaceuticals, fine chemicals and food additives. Petition 870240109895, dated 12 / 24 / 2024, pp. 40 / 53

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