Compositions containing ethyl levulinate and mixtures thereof with diols and diol ethers, used as fragrance carriers in air care applications.

Abstract

The fragrance carrier composition comprises a levulinic acid-based solvent and a glycol-based solvent. The fragrance carrier composition is a non-ideal mixture. The fragrance delivery system includes a fragrance delivery device. The fragrance delivery device includes a reservoir, a porous medium, and a diffuser. At least a portion of a first end of the porous medium is disposed in the reservoir, and the opposite end of the porous medium is located near the diffuser. The reservoir contains the fragrance and the fragrance carrier composition. A method for diffusing the fragrance into the air includes diffusing the fragrance from a fragrance solution into the atmosphere surrounding the fragrance delivery system. The fragrance solution contains the fragrance and the fragrance carrier composition.

Description

Background Technology

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 595,086, filed November 1, 2023, the entire contents of which are hereby incorporated herein by reference for all purposes.

[0002] In fragrance delivery systems, a porous wick made of polymer is often partially immersed in a reservoir containing fragrance and solvent or solvent mixture. The solvent or solvent mixture is used as a carrier to deliver the fragrance to a portion of the porous wick, thereby diffusing it into the atmosphere. Due to wicking in the porous medium, the liquid mixture travels upward through the wick until the liquid front reaches the surface of the wick, where it begins to evaporate and diffuse into the air in a specific order based on the relative vapor pressure and local mole fraction at the liquid-gas interface. Heaters, piezoelectric systems, or electrospray systems are often implemented at the top of the wick to optimize the evaporation process.

[0003] Unfortunately, ensuring a constant liquid delivery at the top of the cartridge to maintain a constant fragrance delivery is often a challenge. Furthermore, many solvents currently used as fragrance carriers are classified as VOCs (volatile organic compounds), which are increasingly attracting environmental and regulatory concerns. Summary of the Invention

[0004] This summary is provided to introduce selected concepts further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help limit the scope of the claimed subject matter.

[0005] In one aspect, the embodiments disclosed herein relate to a fragrance carrier composition comprising a levulinic acid-based solvent and a diol-based solvent. The fragrance carrier composition may be a non-ideal mixture.

[0006] In another aspect, embodiments of this document relate to a fragrance delivery system comprising a fragrance delivery device. The fragrance delivery device includes a reservoir, a porous medium, and a diffuser. At least a portion of a first end of the porous medium is disposed in the reservoir, and an opposite end of the porous medium is located near the diffuser. The reservoir contains a fragrance and a fragrance carrier composition.

[0007] In another aspect, embodiments of this document relate to a method for diffusing a fragrance into the air, the method comprising diffusing the fragrance from a fragrance solution into the atmosphere surrounding a fragrance delivery system. The fragrance solution comprises a fragrance and a fragrance carrier composition.

[0008] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims. Attached Figure Description

[0009] Figure 1A A comparison of infrared spectra (absorbance) of pure ethyl levulinate (EL), pure butanediol (BG), and a binary mixture of these solvents (1:1, w / w) is shown.

[0010] Figure 1B A comparison of infrared spectra (absorbance) of pure ethyl levulinate (EL), pure tripropylene glycol monomethyl ether (TPM), and a binary mixture of these solvents (1:1, w / w) is shown.

[0011] Figure 1C A comparison of infrared spectra (absorbance) of pure ethyl levulinate (EL), pure dipropylene glycol (DPG), and a binary mixture of these solvents (1:1, w / w) is shown.

[0012] Figure 2A A scheme for a polymer wick immersed in a reservoir according to one or more embodiments is shown.

[0013] Figure 2B A liquid-sensitive paper for time tracking is shown according to one or more embodiments.

[0014] Figure 3A This is a graph showing the experimental dynamic viscosity (η) changes of binary blends using butanediol (BG) as the base (“heavier”) solvent and “lighter” solvents of different weight fractions (Xi) at 25°C.

[0015] Figure 3B yes Figure 3A The figure shows the deviation between the experimental viscosity of the mixture and the theoretical viscosity of the ideal binary mixture.

[0016] Figure 4A This is a graph showing the experimental dynamic viscosity (η) changes of binary blends at 25°C using tripropylene glycol monomethyl ether (TPM) as the base (“heavier”) solvent and “lighter” solvents of different weight fractions (Xi).

[0017] Figure 4B yes Figure 4A The figure shows the deviation between the experimental viscosity of the mixture and the theoretical viscosity of the ideal binary mixture.

[0018] Figure 5A This is a graph showing the experimental dynamic viscosity (η) changes of binary blends using dipropylene glycol (DPG) as the base (“heavier”) solvent and “lighter” solvents of different weight fractions (Xi) at 25°C.

[0019] Figure 5B yes Figure 5AThe figure shows the deviation between the experimental viscosity of the mixture and the theoretical viscosity of the ideal binary mixture.

[0020] Figure 6 This is a graph showing the diffusion rate / dynamic viscosity ratio in a wick of a binary blend using butanediol (BG) as the base (“heavier”) solvent and “lighter” solvents of different weight fractions (Xi) at room temperature.

[0021] Figure 7 This is a graph showing the diffusion rate / dynamic viscosity ratio in a wick of a binary blend using TPM as the base (“heavier”) solvent and “lighter” solvents of different weight fractions (Xi) at room temperature.

[0022] Figure 8 This is a graph showing the diffusion rate / dynamic viscosity ratio in a wick of a binary blend using DPG as the base (“heavier”) solvent and “lighter” solvents of different weight fractions (Xi) at room temperature. Detailed Implementation

[0023] The embodiments disclosed herein relate to compositions used as fragrance carriers in air care applications. In particular, the embodiments disclosed herein relate to compositions containing a levulinic acid-based solvent as a fragrance carrier. Advantageously, compositions containing a levulinic acid-based solvent can reduce the viscosity of the glycols and glycol ethers in the mixture to a greater extent than previously anticipated, and in fact, levulinic acid-based solvents can reduce the viscosity of the glycols and glycol ethers in the mixture to a greater extent than would be expected or predicted by one of ordinary skill in the art. This is because levulinic acid-based solvents unexpectedly exhibit non-ideal behavior in binary mixtures, including when levulinic acid-based solvents are combined with glycols and glycol ethers in the mixture. When using a low-viscosity mixture as a fragrance carrier composition, faster diffusion through the porous wick can be obtained, and thus a constant delivery of fragrance at the top of the wick is maintained for the evaporation process to occur. In contrast, glycol-based solvents exhibit high surface energy and therefore high viscosity, presenting challenges when using glycols and glycol ethers as fragrance carriers. Such challenges include ensuring a constant liquid delivery at the top of the wick to maintain a constant delivery of fragrance. According to Darcy's law, fluid flow in porous media is inversely related to viscosity, making reducing carrier viscosity an important tuning parameter to ensure constant fragrance delivery. Advantageously, this lower viscosity is achieved when using levulinic acid-based solvents such as ethyl levulinate.

[0024] Furthermore, the unexpectedly non-ideal behavior of levulinic acid-based solvents has unsurprisingly allowed blends or mixtures of levulinic acid-based and glycol-based solvents to have lower viscosities compared to glycol-based solvents alone, and has also allowed the use of higher amounts of glycol-based solvents while still providing acceptable viscosity characteristics. Similarly, the unexpectedly non-ideal behavior of levulinic acid-based solvents has also unsurprisingly allowed blends or mixtures of levulinic acid-based and glycol-based solvents to contain lower amounts of levulinic acid-based solvents while still providing acceptable viscosity characteristics.

[0025] Furthermore, many fragrance carriers are classified as VOCs, which are increasingly attracting environmental and regulatory attention. Some conventional fragrance carrier solvents are classified as low vapor pressure VOCs, meaning they have a vapor pressure of less than 0.1 mmHg at 20°C. For example, conventional carrier solvents DBE™ LVP (available from Invista), dipropylene glycol methyl ether acetate (DPMA), and isopropyl glycerol (IPG) have vapor pressures of 0.04 mmHg, 0.08 mmHg, and 0.04 mmHg, respectively, at 20°C. Advantageously, ethyl levulinate is a low vapor pressure VOC solvent with a higher vapor pressure than conventional solvents used in air care applications. This advantageously allows for lower temperatures in air care devices, energy savings, maintenance of evaporation rates, and compliance with environmental and regulatory requirements.

[0026] Typically, due to the widespread use of porous cartridges in fragrance delivery systems, optimizing the flow and delivery of multiple components in liquid mixtures through porous media has broad applications in the air care market. While glycol-based solvents can be used in air care applications, delivering liquids in a continuous manner from the bottom end of a cylindrical porous cartridge within a fragrance reservoir to the top of the cartridge presents a particular challenge. These glycol-based solvents include glycols and glycol ethers. As noted above, glycol-based solvents typically have high surface energy and high viscosity, which leads to inconsistent fragrance delivery to the short top end of the porous cartridge.

[0027] Since fluid flow in porous media is inversely related to viscosity according to Darcy's law, the viscosity of the carrier in glycol-based solvents is an important control parameter to ensure constant and consistent fragrance delivery in many air care systems. Therefore, there remains a need to develop fragrance carrier compositions that utilize only low vapor pressure (VOC) components, particularly for constant fragrance delivery in air care devices, including liquid electric air purifiers (such as heated wicking delivery systems (e.g., cryogenic devices, including cryogenic liquid electric air purifiers)), piezoelectric spray systems, electro-spray devices, aerosol diffusers, venturi devices, or wicking devices (e.g., rattan diffusers).

[0028] One or more embodiments herein relate to the use of solvent mixtures as fragrance carrier compositions for reducing the viscosity of glycol-based solvents and increasing diffusion rates in porous media. In some embodiments, the solvent mixture comprises a binary mixture of a glycol-based solvent and a levulinic acid-based solvent. The additional levulinic acid-based solvent may be a solvent with a lower viscosity compared to the glycol-based solvent. The fragrance carrier compositions of one or more embodiments can be used in fragrance delivery systems.

[0029] Fragrance carrier composition

[0030] In one aspect, the embodiments disclosed herein relate to a fragrance carrier composition. The fragrance carrier composition may comprise a levulinic acid-based solvent. The fragrance carrier composition may comprise a glycol-based solvent and a levulinic acid-based solvent. One or more fragrance carrier compositions of this embodiment may comprise a levulinic acid-based solvent to a glycol-based solvent in a weight ratio (w / w) ranging from 1:99 to 100:0 w / w. One or more fragrance carrier compositions of this embodiment may comprise a levulinic acid-based solvent to a glycol-based solvent in a weight ratio (w / w) ranging from 10:90 to 100:0 w / w. In some embodiments, a fragrance carrier composition exhibiting non-ideal behavior comprises a binary mixture of a levulinic acid-based solvent and a glycol-based solvent in a weight ratio (w / w) ranging from 1:99 to 99:1 w / w. Fragrance carrier compositions exhibiting non-ideal behavior may comprise a binary mixture of a levulinic acid-based solvent and a diol-based solvent in a weight ratio (w / w) ranging from 10:90 to 99:1 w / w. The fragrance carrier compositions of one or more embodiments may contain a ratio of levulinic acid-based solvent to diol-based solvent within the range of 1:99, 5:95, 10:90, 20:80, 25:75, 30:70, 40:60, and 45:55 w / w, with the lower limit of the range being any one of 50:50, 55:45, 60:40, 70:30, 75:25, 80:20, 85:15, 9:91, 95:5, 99:1, and 100:0 w / w, wherein any lower limit may be paired with any mathematically compatible upper limit.

[0031] Aleucylpropionic acid-based solvents can have lower viscosities than glycol-based solvents, resulting in mixtures of levulinic acid-based and glycol-based solvents exhibiting lower viscosities compared to glycol-based solvents. This lower viscosity leads to non-ideal behavior in mixtures of levulinic acid-based and glycol-based solvents. The term "non-ideal behavior" refers to an experimental viscosity in a liquid mixture that deviates from its theoretical viscosity. In mixtures exhibiting non-ideal behavior (i.e., non-ideal mixtures), molecules (e.g., fragrance molecules, solvent molecules, or both) can interact in ways different from those in a pure solvent or an ideal mixture due to changes in intermolecular forces compared to the pure solvent.

[0032] The fragrance carrier composition may have a difference between its theoretical and experimental viscosity greater than 15 mPa·s. In some embodiments, the fragrance carrier composition has a difference between its theoretical and experimental viscosity greater than 20 mPa·s. The fragrance carrier composition may have a difference between its theoretical and experimental viscosity greater than 25 mPa·s. The fragrance carrier composition may have a difference between its theoretical and experimental viscosity greater than 30 mPa·s. The fragrance carrier composition may have a difference between its theoretical and experimental viscosity greater than 35 mPa·s. The fragrance carrier composition may have a difference between its theoretical and experimental viscosity greater than 40 mPa·s.

[0033] In some embodiments, the levulinic acid-based solvent is selected to reduce the viscosity of the glycol-based solvent when the levulinic acid-based solvent and the glycol-based solvent are mixed. The resulting reduced viscosity of the mixture of the levulinic acid-based solvent and the glycol-based solvent can be selected to increase the diffusion rate through the porous medium compared to the diffusion rate through the porous medium by a glycol-based solvent alone. The glycol-based solvent may include one or more selected from glycols and glycol ethers. In some embodiments, the glycol includes compounds selected from the group consisting of butanediol, tripropylene glycol methyl ether, dipropylene glycol, propylene glycol, 1,2-pentanediol, 1,4-pentanediol, and combinations thereof.

[0034] In embodiments where the diol-based solvent includes tripropylene glycol methyl ether (TPM), the difference between the theoretical viscosity and the experimental viscosity can be greater than 0.5 mPa·s. In such embodiments, the difference between the theoretical viscosity and the experimental viscosity is greater than 0.55 mPa·s. The difference between the theoretical viscosity and the experimental viscosity can be greater than 0.6 mPa·s. The difference between the theoretical viscosity and the experimental viscosity can be greater than 0.65 mPa·s. The difference between the theoretical viscosity and the experimental viscosity can be greater than 0.7 mPa·s. The difference between the theoretical viscosity and the experimental viscosity can be greater than 0.75 mPa·s. The difference between the theoretical viscosity and the experimental viscosity is greater than 0.8 mPa·s.

[0035] Solvents based on levulinic acid can include functionalized structures of levulinic acid. The structure of levulinic acid is shown in formula (I) below:

[0036] Formula (I).

[0037] In some embodiments, one or more atoms of the levulinic acid structure are functionalized. Functionalization of levulinic acid may include covalent bonding of one or more carbons in a hydrocarbon chain, esterification of a carboxylic acid group, substitution of a ketone group, ionization of a carboxylic acid group, or a combination thereof. One or more embodiments of the levulinic acid-based solvent may be an ester. For example, the levulinic acid-based solvent may include levulinic esters. In some embodiments, the levulinic ester solvent has a general structure represented by formula (II).

[0038] Equation (II)

[0039] Where R can be C1-C 10 Hydrocarbon group. In some embodiments, R is a hydrocarbon group and includes carbon atoms in a range that is lower limited to any one of 1, 2, and 3 carbons, and upper limited to any one of 3, 4, 5, 6, 7, 8, 9, and 10 carbons, wherein any lower limit can be paired with any mathematically compatible upper limit. In one or more specific embodiments, R is C1-C 10 Hydrocarbon groups, preferably C1-C6 hydrocarbon groups, including C1-C6 hydrocarbon groups. 10 Alkyl or alkenyl, preferably C1-C6 alkyl or alkenyl. In some embodiments, R is preferably a C2-C6 hydrocarbon group, including C2-C6 alkyl or alkenyl; more preferably a C2-C3 hydrocarbon group, including ethyl, butyl, and mixtures thereof. In some embodiments, R may be a saturated or unsaturated hydrocarbon group. In some embodiments, the levulinic acid-based solvent may contain at least 90 wt.% of a levulinic acid ester solvent having formula (II). In particularly preferred embodiments, the levulinic acid-based solvent may contain at least 95 wt.% (including at least 98 wt.%) of a levulinic acid ester solvent having formula (II).

[0040] In one or more specific embodiments, the levulinic acid-based solvent comprises ethyl levulinate as shown in formula (III):

[0041] Formula (III).

[0042] The levulinic acid-based solvent can consist essentially of ethyl levulinate, thus preserving the non-ideal properties of the fragrance carrier composition. For example, the levulinic acid-based solvent, consisting essentially of ethyl levulinate, can contain one or more additional compounds that do not materially affect or alter the non-ideal properties of the fragrance carrier composition. In such embodiments, the non-ideal properties of the fragrance carrier composition coexist with the levulinic acid-based solvent, which is essentially composed of ethyl levulinate. In some embodiments, the levulinic acid-based solvent can contain at least 90 wt.% ethyl levulinate. In particularly preferred embodiments, the levulinic acid-based solvent can contain at least 95 wt.% (including at least 98 wt.%) ethyl levulinate.

[0043] Levylpropionic acid-based solvents can have higher vapor pressures compared to conventional low-vapor-pressure VOC solvents used in air care devices. In some embodiments, levylpropionic acid-based solvents have a vapor pressure value at 20°C selected from the range of 0.085 mmHg to 0.20 mmHg. In some embodiments, levylpropionic acid-based solvents have a vapor pressure value at 20°C selected from the range where the lower limit is any one of 0.085, 0.086, 0.087, and 0.09 mmHg, and the upper limit is any one of 0.09, 0.091, 0.092, 0.095, 0.10, 0.12, 0.15, 0.18, and 0.20 mmHg, wherein any lower limit can be paired with any mathematically compatible upper limit. Levylpropionic acid-based solvents can have a vapor pressure value of 0.2 mmHg or less at 20°C. Solvents based on levulinic acid may have a vapor pressure of 0.15 mmHg or less at 20°C. Solvents based on levulinic acid may have a vapor pressure of 0.10 mmHg or less at 20°C. In one or more specific embodiments, solvents based on levulinic acid have a vapor pressure of 0.09 mmHg or less at 20°C. In some embodiments, solvents based on levulinic acid have a vapor pressure selected from the range of 0.085 mmHg to 0.095 mmHg at 20°C. In some embodiments, solvents based on levulinic acid include methyl levulinate having a vapor pressure of 0.15 mmHg at 20°C. Solvents based on levulinic acid may include ethyl levulinate having a vapor pressure of 0.09 mmHg at 20°C.

[0044] The fragrance carrier composition may have a vapor pressure value in the range of 0.010 mmHg to 0.095 mmHg at 20°C. In some embodiments, the fragrance carrier composition has a vapor pressure value at 20°C selected from the range of any one of 0.010, 0.012, 0.015, 0.020, 0.25, 0.5, 0.75, 0.085, 0.086, 0.087, and 0.09 mmHg at the lower limit and any one of 0.5, 0.75, 0.085, 0.086, 0.087, 0.09, 0.091, 0.092, and 0.095 mmHg at the upper limit, wherein any lower limit may be paired with any mathematically compatible upper limit.

[0045] In some embodiments, the fragrance carrier composition has a wicking diffusion rate (or "diffusion speed") of at least 2.5 mm / min through the polymer material. In some embodiments, the polymer material includes one or more selected from PET, polypropylene, polyethylene, and cellulose. The fragrance carrier composition may have a wicking diffusion rate of at least 4 mm / min through the polymer material. The fragrance carrier composition may have a wicking diffusion rate of at least 5 mm / min through the polymer material. The fragrance carrier composition may have a wicking diffusion rate of at least 7.5 mm / min through the polymer material. The fragrance carrier composition may have a wicking diffusion rate of at least 10 mm / min through the polymer material. The fragrance carrier composition may have a wicking diffusion rate of at least 12 mm / min through the polymer material. The fragrance carrier composition may have a wicking diffusion rate of at least 15 mm / min through the polymer material. The fragrance carrier composition may have a wicking diffusion rate of at least 20 mm / min through the polymer material. The fragrance carrier composition may have a wicking diffusion rate of at least 25 mm / min through the polymer material. The fragrance carrier composition may have a wicking diffusion rate of at least 30 mm / min through the polymer material. The fragrance carrier composition may have a wick diffusion rate of at least 35 mm / min through the polymer material. The fragrance carrier composition may have a wick diffusion rate of at least 40 mm / min through the polymer material. The fragrance carrier composition may have a wick diffusion rate of at least 45 mm / min through the polymer material. The fragrance carrier composition may have a wick diffusion rate of at least 50 mm / min through the polymer material.

[0046] Spice delivery system

[0047] In another aspect, embodiments of this document relate to a fragrance delivery system. In some embodiments, the fragrance delivery system includes a fragrance delivery device comprising a reservoir, a porous medium, and a diffuser. One or more embodiments of the fragrance delivery system may be an air care device comprising one or more selected from heated wicking delivery systems, piezoelectric spray systems, electro-spray systems, aerosol devices including aerosol diffusers, venturi devices, or wicking devices.

[0048] As will be understood by those skilled in the art, a fragrance delivery system may include a power source configured to power the diffuser of the fragrance delivery device, enabling the diffuser to have sufficient power to operate and diffuse the fragrance from the fragrance carrier composition into the atmosphere. In some embodiments, the fragrance delivery system includes one or more electrical connections configured to couple the fragrance delivery system to an electrical power source. In such embodiments, the electrical power source coupled to the fragrance delivery system is configured to facilitate the diffusion of the fragrance from the fragrance carrier composition into the atmosphere.

[0049] The diffuser of the fragrance delivery device can be configured to diffuse aromatic compounds from a fragrance solution. The fragrance solution can be present in a reservoir of the fragrance delivery device. The fragrance solution can be a fragrance mixture comprising a fragrance and a fragrance carrier composition. The fragrance carrier composition can be as described above. The fragrance can be a compound soluble in a levulinic acid-based solvent, a glycol-based solvent, or both. In such embodiments, the fragrance can be an essential oil. The fragrance can be a compound having a vapor pressure in the range of 0.05 to 1.5 mmHg at 20°C. The flavoring can be a compound having a vapor pressure value selected from the range of 0.05, 0.06, 0.065, 0.7, 0.075, 0.10, 0.15, 0.25, 0.5 and 0.75 mmHg at 20°C, with the lower limit being any one of 0.05, 0.06, 0.065, 0.25, 0.30, 0.50, 0.65, 0.75, 0.80, 0.90, 0.95, 0.98, 1.0, 1.05, 1.10, 1.15, 1.20 and 1.50 mmHg, wherein any lower limit can be paired with any mathematically compatible upper limit. In some embodiments, the fragrance may preferably be a compound having a vapor pressure at 20°C in the range of 0.1 to 0.9 mmHg, more preferably in the range of 0.1 to 0.75 mmHg.

[0050] The fragrance solution may contain a fragrance in an amount that allows the fragrance carrier composition to maintain its form as a non-ideal mixture. The fragrance may contain a fragrance in an amount that allows the non-ideal behavior of the fragrance carrier composition to be maintained. In some embodiments, the fragrance solution contains a fragrance and a fragrance carrier composition in a ratio within the range of any one of 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 50:50, and 60:40 w / w, with the lower limit being any one of 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 60:40, and 65:35 w / w. Non-limiting examples of fragrance solutions for plug-in diffuser fragrance delivery systems may include fragrance and fragrance carrier compositions in the range of 60:40 to 40:60 w / w. Non-limiting examples of fragrance solutions for passive diffuser fragrance delivery systems may include fragrance and fragrance carrier compositions in the range of 10:90 to 30:70 w / w. The fragrance solution may contain a fragrance in an amount such that the fragrance delivery system continuously delivers the fragrance for at least 2 weeks (including at least 3 weeks, and preferably at least 4 weeks).

[0051] A diffuser can be configured to diffuse a fragrance from a fragrance solution that has traveled from a reservoir through a first end of a porous medium to a top end of the porous medium. In some embodiments, the diffuser includes a heater, a piezoelectric spray system, an electro-spray system, a rattan diffuser rod, or a combination thereof.

[0052] The porous medium can have an elongated shape. In such embodiments, the porous medium may have at least a first end and a second end. The porous medium having an elongated shape can be flat, circular, or a combination thereof. The porous medium may have a top end located near a diffuser and a bottom end disposed in a reservoir of the spice delivery device. The diffuser may be coupled to the reservoir. The porous medium of the spice delivery device may be a wick, a rattan diffuser rod, or a combination thereof. In some embodiments, the porous medium comprises a polymeric material. The polymeric material may include one or more selected from PET, polypropylene, polyethylene, cellulose, and other polymers.

[0053] In embodiments where the porous medium includes a rattan diffuser rod, the material of the rattan diffuser rod may be a diffuser. In such embodiments, the rattan diffuser rod may be disposed in a reservoir having an opening through which a top end of the rattan diffuser rod passes. The top end of the rattan diffuser rod can sufficiently diffuse the fragrance from the solution in the reservoir into the atmosphere. In embodiments where the porous medium includes a wick, the wick may comprise a polymer material, including but not limited to polyethylene terephthalate (PET). In one or more embodiments, at least a portion of the first end of the porous medium is disposed in the solution of the reservoir of the fragrance delivery device.

[0054] Methods for delivering spices

[0055] In another aspect, embodiments of this document relate to a method for delivering a fragrance into the atmosphere. This method may include preparing a fragrance solution comprising a fragrance and a fragrance carrier composition in a fragrance delivery system. The fragrance carrier composition and the fragrance delivery system may be as described above.

[0056] Preparing a fragrance solution may include adding a fragrance to a fragrance carrier composition to form a fragrance solution. In such embodiments, the fragrance solution may be prepared in a reservoir of a fragrance delivery system. In some embodiments, a fragrance solution may be prepared and then added to a reservoir of a fragrance delivery system. One or more embodiments of the method may include reducing the viscosity of a glycol-based solvent by adding a levulinic acid-based solvent to a glycol-based solvent.

[0057] The thermodynamic characteristics of one or more of the fragrance carrier compositions of the embodiments can be characterized by one or more analytical methods, including but not limited to spectroscopic analysis. Spectroscopic analysis may include infrared spectroscopy (e.g., Fourier transform infrared spectroscopy) coupled to an attenuated total reflectance (ATR) sample chamber (e.g., an ATR crystal). As will be understood by those skilled in the art, infrared (IR) light is irradiated onto and interacts with the sample in the sample chamber. The IR light that has interacted with the sample is then detected to produce a Fourier transform infrared (FT-IR) spectrum, which is unique to each sample and can be used to identify, characterize, and quantify the different substances present in the sample. A fragrance carrier composition characterized by IR-ATR exhibiting non-ideal behavior may have a spectrum with shifted bands, bands of different shapes, or both, compared to the IR-ATR spectrum of a pure solvent. These variations can indicate changes in intermolecular forces, thereby indicating non-ideal behavior in the solvent blend. For example, the IR-ATR spectrum of one or more of the fragrance carrier compositions of the embodiments may have variations in spectral bands corresponding to changes in the hydrogen bonds of the mixture compared to the hydrogen bonds of the pure solvent.

[0058] In some embodiments, the method includes determining the difference between the theoretical viscosity and the experimental viscosity of the fragrance carrier composition. The difference between the theoretical viscosity and the experimental viscosity of the fragrance carrier composition can indicate that the fragrance carrier composition exhibits non-ideal behavior.

[0059] In some embodiments, the method may include passing a fragrance solution from a first end of a porous medium disposed in a reservoir of a fragrance delivery system through the porous medium to a second end of the porous medium. The fragrance solution may be transferred from the first end of the porous medium to the second end of the porous medium at a constant rate. In one or more specific embodiments, a levulinic acid-based solvent of the fragrance carrier composition increases the diffusion rate of the fragrance carrier composition through the porous medium compared to the diffusion rate of a diol-based solvent through the porous medium. The porous medium may comprise one or more polymeric materials as described above.

[0060] In one or more embodiments, the second end of the porous medium may be located near a diffuser that can be coupled to a power source. In such embodiments, operating the diffuser facilitates the diffusion of the fragrance from the fragrance solution in the second end of the porous medium into the atmosphere. In one or more embodiments, the fragrance is diffused from the fragrance solution into the atmosphere surrounding the fragrance delivery system, thereby delivering the fragrance into the atmosphere.

[0061] One or more embodiments of the method may include determining the wick diffusion rate of a fragrance carrier composition. In such embodiments, the diffusion rate of the solvent blend is determined by measuring the time taken for the solvent front to travel from the bottom end of a wick disposed in a solvent reservoir to the top end of the wick. One or more embodiments of the method may include determining whether the fragrance carrier composition is a non-ideal mixture. In such embodiments, one or more embodiments of the method may include determining the difference between the theoretical viscosity and the experimental viscosity of the fragrance carrier composition. In such embodiments, the experimental viscosity can be determined by measuring the viscosity of the solvent blend, such as using an Anton Paar SVM 3001 viscometer. The theoretical dynamic viscosity can be determined by equation (1).

[0062] Equation (1)

[0063] in It is the theoretical dynamic viscosity of the solvent blend; It is the mole fraction of pure component i; and It is the dynamic viscosity of pure component i.

[0064] One or more embodiments of this document relate to the use of levulinic acid-based solvents (such as ethyl levulinate and mixtures thereof) for dissolving and / or carrying fragrances. Notably, this includes liquid electric air fresheners (such as heated wick delivery systems), piezoelectric spray systems, electro-spray devices, venturi devices, or wicking devices acting as rattan diffusers, all used in air care devices. A key element of this invention relies on the unique and optimized delivery behavior of ethyl levulinate and its mixtures with glycols and glycol ethers in porous media commonly used in fragrance delivery systems. Ethyl levulinate, in particular, reduces the viscosity of glycols and glycol ethers in the mixture composition, thereby preventing non-ideal behavior in binary mixtures. This reduced viscosity drives faster diffusion of the mixture within the device, allowing for optimized and consistent fragrance delivery. Example

[0065] The performance of ethyl levulinate in binary mixtures of ethyl levulinate with butanediol, tripropylene glycol methyl ether, and dipropylene glycol for reducing viscosity and increasing diffusion in porous wicks was compared with other light solvents used for the same purpose in air care. Experiments showed that the viscosity of blends of glycols and glycol ethers with ethyl levulinate was reduced compared to solvents containing isopropyl glycerol (IPG), dipropylene glycol methyl ether acetate (DPMA), and dipropylene glycol monomethyl ether (DPM). Binary systems containing ethyl levulinate and butanediol, ethyl levulinate and tripropylene glycol monomethyl ether, and ethyl levulinate and dipropylene glycol exhibited deviations from ideal mixtures and lower viscosity values ​​compared to other solvents commonly used as fragrance carriers.

[0066] Material

[0067] Butylene glycol (BG), dipropylene glycol methyl ether acetate (DPMA), dimethyl glutate, dimethyl adipate, ethyl levulinate (EL), and dipropylene glycol monomethyl ether (DPM) were all obtained from Sigma-Aldrich. Tripropylene glycol methyl ether (TPM) was obtained from Dow Chemicals. Isopropylglycerin (IPG) was obtained from Solvay. Dipropylene glycol (DPG) was obtained from Thermo Scientific. Dimethyl glutate (DMG) and dimethyl adipate (DMA) were used to prepare a synthetic mixture (DMG / DMA) to mimic the commercial solvent DBE™ LVP (available from Invista).

[0068] Example 1: Spectral characterization of binary mixtures

[0069] Pure samples of EL, BG, TPM, and DPG, as well as 1:1 w / w blends of EL:BG, EL:TPM, and EL:DPG, were analyzed using Fourier transform infrared spectroscopy (FTIR). FTIR spectra of each sample were acquired on a Bruker ALPHA II compact FT-IR spectrometer coupled to an ATR crystal. To analyze each of the pure solvents and binary mixtures, three (3) drops of sample were placed in the ATR crystal of the Bruker ALPHA II instrument, and FTIR spectra were obtained from 600 cm⁻¹. -1 Up to 4000cm -1 The absorbance. The IR spectra of the pure solvent and the blend are presented in Figure 1A-1C middle.

[0070] like Figures 1A to 1C As shown, the spectra recorded for pure glycols and glycol ethers show a dominant 3650 cm⁻¹. -1 Up to 3200cm -1 A broad band in the region corresponds to a prominent hydroxyl group and indicates the presence of hydrogen bonds between glycol / glycol ether molecules in the pure state. Other characteristic peaks correspond to the CH and CO vibrations of the hydroxyl group in the pure solvent. In the case of EL, a peak at 1723 cm⁻¹ can be identified. -1 The sharp spectral band at [location] (characteristic of the presence of C=O functional groups), and the 1159 cm⁻¹ band corresponding to the COC vibration. -1 Strong spectral band at that location.

[0071] In each spectrum recorded for the binary mixture, the characteristic OH band shifted to a higher frequency compared to pure glycol / glycol ether (e.g., from 3316 cm⁻¹ in pure BG). -1 Shifted to 3355 cm in the mixture with EL -1 ( Figure 1A ); from pure TPM 3472 cm -1 Shifted to 3480 cm in the mixture with EL -1 ( Figure 1B ); and from pure DPG 3350 cm -1 3423 cm offset to the mixture with EL -1In each blend, the OH bands showed significant changes in shape and absorption maxima, indicating that the intermolecular hydrogen bonds present in the blends are weaker than those present in pure glycol / glycol ethers. Therefore, for binary blends between ethyl levulinate and glycol / glycol ethers, lower-than-expected viscosities were observed (e.g., a negative change (Δη) in experimental viscosity relative to theoretical viscosity) (as presented in Tables 6, 11, and 16), characterizing EL / BG, EL / TPM, and EL / DPG as non-ideal binary blends.

[0072] Example 2:

[0073] Various blends were prepared based on the weight ratios (w / w) and concentrations presented in Table 1.

[0074] Table 1: Composition of blends.

[0075]

[0076] It was prepared using 73% by weight of dimethyl glutarate (DMG) and 27% by weight of dimethyl adipate (DMA).

[0077] Example 3: Measuring the diffusion rate of the wick.

[0078] The wick diffusion rate (in millimeters per second (mm / s) of each of the sample mixtures 1 to 53 prepared according to Table 1 was measured using a standard polyethylene terephthalate (PET) wick (dimensions: length: 76 mm; diameter: 7 mm). Figure 2A Add 3.5 g of the blend to the bottle shown. Attach the PET cartridge to the system by immersing a portion of the bottom end of the cartridge in the blend to avoid radial penetration. At this point, initialize the precision timer. Every 30 seconds, evaluate the cartridge saturation of the system by bringing the liquid-sensitive paper into contact with the top of the cartridge to determine if the blend has reached the top end of the cartridge. Figure 2B As shown. When a complete circular spot is observed on the liquid-sensitive paper, record the time on the precision timer and determine the total time (min).

[0079] Example 4: Measuring the viscosity of blends

[0080] The dynamic viscosity (in millipascal-second, mPa·s) and kinematic viscosity (in millimeters squared per second, mm²) of a portion of each of the samples 1 to 53 listed in Table 1 were measured using an Anton Paar SVM 3001 viscometer. 2The viscosity is measured and recorded. In this viscometer, the viscosity measurement cell comprises a tube that rotates at a constant speed and is filled with a sample fluid, while a measuring rotor with a built-in magnet floats in the sample. The shear force of the sample drives the rotor, while the magnetic force delays its rotation. When the rotor reaches an equilibrium speed, the viscosity of the fluid is determined. The kinematic viscosity is calculated from the dynamic viscosity and density of the sample.

[0081] The device was purged with 2 mL of each sample, followed by measurement using a 5 mL syringe. After purging, 1 mL of sample was added to the device using the same syringe, and viscosity and density measurements were performed automatically. The recorded dynamic viscosity (mPa·s) and density (g / cm³) for samples 1-53 are shown below. 3 ) and the calculated kinematic viscosity (mm² / s²) 2 The diffusion time (in minutes) is shown in Table 2 along with the wick diffusion time (in seconds).

[0082] Table 2 Viscosity, density, and time to complete wick diffusion.

[0083]

[0084] Example 5: Calculating the changes in experimental viscosity and theoretical viscosity

[0085] Since the experimental viscosities of most samples were obtained as shown in Table 2, the difference (Δη) between the experimental and theoretical viscosities can be calculated to determine the deviation from the ideal behavior of the mixture. Additionally, sample diffusion through the PET wick was calculated in millimeters per minute (mm / min). Tables 3 through 16 present these values ​​for each solvent blend listed in Tables 1 and 2.

[0086] Table 3. Dynamic viscosity, viscosity deviation and wicking diffusion of IPG / BG blends.

[0087]

[0088] Table 4. Dynamic viscosity, viscosity deviation and wicking diffusion of DPMA / BG blends.

[0089]

[0090] Table 5. Dynamic viscosity, viscosity deviation and wicking diffusion of DPM / BG blends.

[0091]

[0092] Table 6. Dynamic viscosity, viscosity deviation and wicking diffusion of EL / BG blends.

[0093]

[0094] Table 7. Dynamic viscosity, viscosity deviation and wicking diffusion of DMG / DMA / TPM blends.

[0095]

[0096] Table 8. Dynamic viscosity, viscosity deviation and wicking diffusion of IPG / TPM blends.

[0097]

[0098] Table 9. Dynamic viscosity, viscosity deviation and wicking diffusion of DPMA / TPM blends.

[0099]

[0100] Table 10. Dynamic viscosity, viscosity deviation and wicking diffusion of DPM / TPM blends.

[0101]

[0102] Table 11. Dynamic viscosity, viscosity deviation and wicking diffusion of EL / TPM blends.

[0103]

[0104] Table 12. Dynamic viscosity, viscosity deviation and wicking diffusion of DMG / DMA / DPG blends.

[0105]

[0106] Table 13. Dynamic viscosity, viscosity deviation and wicking diffusion of IPG / DPG blends.

[0107]

[0108] Table 14. Dynamic viscosity, viscosity deviation and wicking diffusion of DPMA / DPG blends.

[0109]

[0110] Table 15. Dynamic viscosity, viscosity deviation and wicking diffusion of DPM / DPG blends.

[0111]

[0112] Table 16. Dynamic viscosity, viscosity deviation and wicking diffusion of EL / DPG blends.

[0113]

[0114] As shown in Tables 3 to 16 and Figures 3A to 5B As shown, blends containing ethyl levulinate as a solvent unexpectedly exhibit a decrease in viscosity relative to the expected or theoretical viscosity levels. Notably, blends of ethyl levulinate with butanediol, TPM, and DPG unexpectedly result in a decrease in viscosity compared to commercial solvents used in air purifiers (i.e., DBE). TM Compared to LVP, IPG, DPMA, and DPM, these ethyl levulinate (ELE) exhibit faster wick diffusion rates and greater deviations from the ideal behavior of the mixture. Therefore, the above data indicate that binary solvent blends of ELE with one of the following—butanediol, TPM, or DPG—unexpectedly produce non-ideal mixtures. Furthermore, as demonstrated in diffusion studies using PET wicks, the reduced viscosity of these non-ideal ELE blends results in a faster diffusion rate through the wick, allowing for a constant rate of fragrance delivery to the top of the wick for evaporation near the diffuser. This constant fragrance delivery can achieve a constant fragrance evaporation rate when using heated diffusers, piezoelectric spray systems, electrospray devices, or Venturi devices.

[0115] Figures 3A to 5B The viscosity exhibits a variation with the weight fraction (Xi) of the lighter solvent (e.g., a commercial solvent) in the blend with butanediol, TPM, and DPG, and a viscosity deviation from the ideal binary mixture. Figures 3A to 5B As shown, ethyl levulinate unexpectedly reduced the viscosity of the blend compared to other commercial solvents (DPMA, DPM, DBE). TM The extent to which LVP and IPG blends are more abundant is greater than that of blends of LVP and IPG. Therefore, the results show that the binary mixture of diol-based solvents with ethyl levulinate forms a non-ideal mixture.

[0116] It was determined that the viscosity reduction of the binary solvent blend with ethyl levulinate has a direct impact on the diffusion rate of the solvent blend in the wick, which in... Figures 6 to 8 The results are presented graphically. In each binary solvent blend of ethyl levulinate (i.e., a solvent blend of ethyl levulinate with each of butanediol, TPM, and DPG), when the concentration of ethyl levulinate in the solvent blend is at a weight ratio of 25:75 or greater, ethyl levulinate promotes an increased diffusion rate to a greater extent than other commercial solvents.

[0117] The embodiments disclosed herein can provide at least one of the following advantages. The presence of ethyl levulinate in the fragrance carrier composition can reduce the viscosity of the glycol and glycol ether and provide non-ideal behavior in binary mixtures. When these low-viscosity mixtures are used as fragrance carrier compositions in fragrance delivery systems, faster diffusion can be achieved in porous wicks compared to individual commercial solvents and glycol-based solvents. Therefore, this viscosity reduction can maintain constant fragrance delivery, thereby achieving consistent diffusion of the fragrance into the atmosphere.

[0118] While only a few exemplary embodiments have been described in detail above, those skilled in the art will readily understand that many modifications can be made to the exemplary embodiments without substantially departing from the invention. Therefore, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

1. A fragrance carrier composition comprising: Solvents based on levulinic acid; and Based on diol solvents, The fragrance carrier composition is a non-ideal mixture.

2. The fragrance carrier composition of claim 1, wherein, The solvent based on levulinic acid has formula (II): Equation (II) Where R is C1-C 10 Hydrocarbon groups, preferably C1-C6 hydrocarbon groups.

3. The fragrance carrier composition according to claim 2, wherein, R is C1-C 10 Alkyl or alkenyl, preferably C1-C6 alkyl or alkenyl.

4. The fragrance carrier composition of claim 2, wherein, R is a C2-C6 hydrocarbon group, preferably a C2-C6 alkyl or alkenyl group, more preferably a C2-C3 hydrocarbon group, including ethyl, butyl and mixtures thereof.

5. The fragrance carrier composition of claim 1, wherein, The solvent based on levulinic acid includes levulinic esters.

6. The fragrance carrier composition of claim 2, wherein, The levulinic acid-based solvent contains at least 90 wt.%, preferably at least 95 wt.%, more preferably at least 98 wt.% of formula (II).

7. The fragrance carrier composition of claim 1, wherein, The levulinic acid-based solvent has formula (III): Formula (III).

8. The fragrance carrier composition of claim 7, wherein, The levulinic acid-based solvent contains at least 90 wt.%, preferably at least 95 wt.%, more preferably at least 98 wt.% of formula (II).

9. The fragrance carrier composition as claimed in any one of the preceding claims, wherein, The levulinic acid-based solvent has a vapor pressure of 0.20 mmHg or less at 20°C.

10. The fragrance carrier composition as claimed in any one of the preceding claims, wherein, The levulinic acid-based solvent has a vapor pressure of 0.09 mmHg or less at 20°C.

11. The fragrance carrier composition as claimed in any of the preceding claims, wherein, The levulinic acid-based solvent reduces the viscosity of the diol-based solvent.

12. The fragrance carrier composition as claimed in any of the preceding claims, wherein, The diol-based solvent is selected from the group consisting of: diols, diol ethers, and combinations thereof.

13. The fragrance carrier composition of claim 12, wherein, The diol-based solvent is selected from the group consisting of: propylene glycol, 1,2-pentanediol, 1,4-pentanediol, butanediol, tripropylene glycol methyl ether, dipropylene glycol, and combinations thereof.

14. The fragrance carrier composition as claimed in any of the preceding claims, wherein, Based on the total weight (w / w) of the flavor carrier composition, the ratio of the levulinic acid-based solvent to the diol-based solvent is in the range of 10:90 to 100:0 by weight percentage.

15. A spice delivery system comprising: A spice delivery device comprising: Storage container; Porous media; and Diffuser, At least a portion of the first end of the porous medium is disposed in the reservoir, and the opposite end of the porous medium is located near the diffuser. The reservoir contains a fragrance and a fragrance carrier composition as described in any one of the preceding claims.

16. The spice delivery system of claim 15, wherein, The porous medium is a suction core, a rattan diffuser rod, or a combination thereof.

17. The spice delivery system of claim 15 or 16, wherein, The diffuser includes a heater, a piezoelectric spray system, an electro-spray system, an aerosol diffuser, a rattan diffuser rod, or a combination thereof.

18. The spice delivery system according to any one of claims 15 to 17, wherein, The spice delivery system is selected from one or more of a heated wick delivery system, a piezoelectric spray system, an electro-spray system, a venturi device, or a wicking device.

19. A method for diffusing fragrance into the air, the method comprising: The fragrance is diffused from a fragrance solution into the atmosphere surrounding the fragrance delivery system, the fragrance solution containing the fragrance and the fragrance carrier composition as described in any one of claims 1 to 14.

20. The method of claim 19, further comprising passing the fragrance solution from a first end of a porous medium disposed in a reservoir of the fragrance delivery system through the porous medium to a second end of the porous medium.

21. The method of claim 20, wherein, The fragrance solution is transferred from the first end of the porous medium to the second end of the porous medium at a constant rate.

22. The method of claim 20 or 21, wherein, Compared to the diffusion rate of the diol-based solvent through the porous medium, the levulinic acid-based solvent increases the diffusion rate of the fragrance carrier composition through the porous medium.

23. Use of levulinic acid-based solvents as fragrance carriers in air care applications.

24. Use of the fragrance carrier composition as a fragrance carrier in air care applications as described in any one of claims 1 to 14.

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