Odorants for fluids, odorized fluids, methods, and systems

Abstract

Odorants and odorant compositions that include a hexyne, a heptyne, or an octyne, such as a 1-hexyne, a 2-hexyne, a 2-heptyne, a 3-heptyne, a 3-octyne, or a 4-octyne are disclosed. Methods of odorizing a material, such as a fluid are provided. The fluid can be a gas, such as hydrogen gas, methane gas, or combination thereof. Odorized fluids that include a fluid and an odorant or odorant composition are disclosed. Methods of generating energy that can include contacting an anode of a fuel cell with an odorized fluid that includes an odorant and hydrogen gas, methane gas, or a combination thereof are also disclosed. Systems that include an odorant or odorant composition, and a sensor are provided.

Description

ODORANTS FOR FLUIDS, ODORIZED FLUIDS, METHODS, AND SYSTEMSREFERENCE TO RELATED APPLICATIONS

[0001] This application is being filed on April 8, 2025, as a PCT International Patent Application and claims the benefit of and priority to U.S. Provisional Patent Application Nos. 63 / 631,534 and 63 / 631,556, filed on April 9, 2024, the disclosures of which are incorporated herein by reference in their entirety.TECHNICAL FIELD

[0002] This disclosure relates to odorants for fluids, such as fuel gases, odorized fluids, and methods for odorizing fluids, such as fuel gases.BACKGROUND

[0003] Odorants have been added to fluids, including various dangerous gases, for decades. Odorants can allow for the detection of a leak without external equipment. Odorants can also allow for leak detection in locations where it can be difficult or impossible to place detectors, such as outdoor locations. Since odorants that are easily detectable by the human olfactory system can be used, small fluid leaks can be easily detected.

[0004] Sulfur compounds that are commonly used as odorizing agents include tetrahydrothiophene, / c77-butylmcrcaptan, dimethyl sulfide, and ethyl mercaptan. Fuel gases that do not have sufficient intrinsic odor are usually mixed with compounds having an intense smell, e.g., an odorant, so that leaks can be easily perceived. For safety reasons, odorants that are added to fuel gases ideally should have a perceptible odor in a number of circumstances, such as high dilution, and cause an alarm association in humans due to an unpleasant odor.

[0005] Hydrogen is an odorless and hazardous gas. Hydrogen gas has a very low density, which allows it to disperse and mix readily with air, thereby creating explosion or ignition hazards. A hydrogen molecule also is very small and typically has a high diffusion coefficient in other gases and solids. When considering hydrogen leaks, its high buoyancy generally affects gas motion considerably more than its high diffusivity. Hydrogen typically has a flow rate that is about 25% higher than methane through an identical leak and with the same associated pressuredrop. The minimum ignition energy of hydrogen is very low, e.g., lower than natural gas. For one or more of these reasons, the odorization of hydrogen should increase the safety of its use, especially as a fuel gas.

[0006] A promising application for hydrogen includes hydrogen powered fuel cells. Hydrogen fuel cells typically use a catalyst comprising a precious metal to oxidize hydrogen electrochemically at the anode of a cell. If the active sites of the precious metal catalyst are occupied by a molecule other than hydrogen, the activity of the catalyst, and hence the efficiency and performance of the fuel cell, can decrease dramatically. This is commonly referred to as poisoning or deactivation of the catalyst, and it can be particularly problematic when many sulfur-based odorants are used, such as tetrahydrothiophene (THT) and Zc / 7-buty I -mercaptan (TBM) (International Journal of Hydrogen Energy, 41(28), 2016, 12231-12241; Journal of Power Sources, 152, 2005, 226-232).

[0007] In some instances, it can be necessary to remove some odorants from a hydrogen energy system in order to avoid release of the odorant in the environment. This can be a significant concern for hydrogen powered fuel cells because an odorant, ideally, should (i) not chemically interact with a catalyst, and (ii) remain inert. If a fuel cell’s exhaust remains unfiltered, an odorant can be released in the environment, thereby negating the ability to detect a possible hydrogen leak or resulting in a false leak warning. Similarly, applications that require ultra-pure hydrogen can mandate the removal of the odorant from the hydrogen.

[0008] Many sulfur-free hydrogen odorants, however, typically (i) do not have satisfactory olfactory properties (e.g., their smell or odor characteristic is not alarming), (ii) do not have a suitable odor detection threshold (e.g., the compounds have a high odor threshold, which usually requires a high level of odorization), (iii) are not suitable as a gas odorant, and / or (iv) are not suitable for use in conjunction with other odorants in a blend.

[0009] There remains a need for improved methods of odorizing fluids and to identify improved odorants for fluids, including fuel gases such as hydrogen. There also remains a need for odorants that are compatible with fuel cells, such as hydrogen fuel cells, and improved systems of removing odorants from fluids. There also remains a need for odorants having a very low odor perception, a distinctive smell profile, an alarming character, or a combination thereof.SUMMARY

[0010] This summary is provided to introduce various concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify required or essential features of the claimed subject matter, nor is the summary intended to limit the scope of the claimed subject matter.

[0011] In one aspect, odorants are provided, such as odorants for a fluid, which can include a gas. The gas can be a fuel gas. In some embodiments, the odorants include a hexyne, a heptyne, an octyne, or a combination thereof. The hexyne can include a 1 -hexyne, a 2-hexyne, or a combination thereof. The heptyne can include a 2-heptyne, a 3 -heptyne, or a combination thereof. The octyne can include a 3 -octyne, a 4-octyne, or a combination thereof.

[0012] Not wishing to be bound by any particular theory, embodiments of the odorants provided herein, such as the 2- / 3-heptynes and 3- / 4-octynes, surprisingly have a lower odor detection threshold than 1 -heptyne and 1 -octyne, and / or an alarming odor profile compared to 1- heptyne and 1 -octyne. One or both of these features can provide one or more significant safety advantages.

[0013] In another aspect, odorant compositions are provided. In some embodiments, the odorant compositions include an odorant and an additive. The additive can include an odiferous compound, a stabilizer, a diluent, or a combination thereof.

[0014] In a further aspect, methods of odorizing a fluid are provided. In some embodiments, the methods include providing a fluid, and contacting the (i) fluid, such as a gas, and (ii) an odorant or an odorant composition to form an odorized fluid, such as any of those provided herein.

[0015] In yet another aspect, methods of generating energy are provided. In some embodiments, the methods include providing a fuel cell that includes an anode; and contacting the anode and an odorized fluid as provided herein. The contacting of the anode and the odorized fluid can produce an oxidized odorized fluid. The methods also can include removing the odorant from the odorized fluid, the oxidized odorized fluid, or both the odorized fluid and the oxidized odorized fluid.

[0016] In a still further aspect, systems are provided. In some embodiments, the systems include (i) a sensor, and (ii) an odorant or an odorant composition provided herein. A sensor can be configured to permit the use of any of the odorants provided herein at a concentration that isnot detectable by an average human.

[0017] Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the aspects described herein. The advantages described herein can be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 depicts the results of a durability test of an embodiment of a protonexchange membrane fuel cell (PEMFC) using hept-2-yne as a hydrogen odorant.

[0019] FIG. 2 depicts the results of a durability test of an embodiment of a PEMFC using hept-3-yne as a hydrogen odorant.

[0020] FIG. 3 depicts the results of a durability test of an embodiment of a PEMFC using oct-4-yne as a hydrogen odorant.

[0021] FIG. 4 depicts the results of a durability test of an embodiment of a PEMFC using l-hexen-5-yne as a hydrogen odorant.

[0022] FIG. 5 depicts the results of a durability test of an embodiment of a PEMFC using hept-l-en-6-yne as a hydrogen odorant.

[0023] FIG. 6 depicts the results of a durability test of an embodiment of a PEMFC using 3,3-dimethyl-but-l-yne as a hydrogen odorant.

[0024] FIG. 7 depicts the results of a durability test of an embodiment of a PEMFC using hex-l-yne as a hydrogen odorant.

[0025] FIG. 8 depicts the results of a durability test of an embodiment of a PEMFC using hex-2-yne as a hydrogen odorant.

[0026] FIG. 9 depicts the results of a durability test of an embodiment of a PEMFC using butyraldehyde as a hydrogen odorant.

[0027] FIG. 10 depicts the results of a durability test of an embodiment of a PEMFC using tetrahydrothiophene (THT) as a hydrogen odorant.DEFINITIONS

[0028] To define more clearly the terms used herein, the following definitions are provided. Unless otherwise indicated, the following definitions are applicable to this disclosure. If a term is used in this disclosure but is not specifically defined herein, the definition from the IUPAC Compendium of Chemical Terminology, 2ndEd (1997) can be applied, as long as that definition does not conflict with any other disclosure or definition applied herein, or render indefinite or non-enabled any claim to which that definition is applied. To the extent that any definition or usage provided by any document incorporated herein by reference conflicts with the definition or usage provided herein, the definition or usage provided herein controls.

[0029] As the various features of the subject matter of this disclosure are described, within particular aspect, a combination or combinations of the different features may be envisioned. For every aspect of every feature disclosed herein, all combinations that do not detrimentally affect the designs, compositions, systems, processes, or methods described herein are contemplated with or without the express description of that particular combination.Therefore, unless explicitly stated to the contrary, any aspect of feature disclosed here may be combined to describe and disclose the inventive designs, compositions, systems, processes, or methods consistent with the entire disclosure.

[0030] While compositions and methods are described in terms of “comprising” various components or steps, the compositions and methods can also “consist essentially of’ or “consist of’ the various components or steps, unless stated otherwise.

[0031] The terms “including,” “with,” and “having,” as used herein, are defined as comprising (i.e., open language), unless specified otherwise.

[0032] The terms “a,” “an,” and “the” are intended to include plural alternatives, e.g., at least one. For instance, the disclosure of “a fluid,” “a sensor,” and the like, is meant to encompass one, or mixtures or combinations of more than one, fluid, sensor, and the like, unless otherwise specified.

[0033] Various numerical ranges are disclosed herein. When Applicants disclose or claim a range of any type, Applicants’ intent is to disclose or claim individually each possible number that such a range could reasonably encompass, including end points of the range as well as any sub-ranges and combinations of sub-ranges encompassed therein, unless otherwise specified. For example, by disclosing a concentration range of about 5 mg / m3n to about 20mg / m3n, Applicant’s intent is to recite individually 5 mg / m3n, 6 mg / m3n, 7 mg / m3n, 8 mg / m3n, 9 mg / m3n, 10 mg / m3n, 11 mg / m3n, 12 mg / m3n, 13 mg / m3n, 14 mg / m3n, 15 mg / m3n, 16 mg / m3n, 17 mg / m3n, 18 mg / m3n, 19 mg / m3n, and 20 mg / m3n, including any sub-ranges and combinations of sub-ranges encompassed therein, and these methods of describing such ranges are interchangeable. Moreover, all numerical end points of ranges disclosed herein are approximate, unless excluded by proviso. As a representative example, if Applicants state that one or more steps in the processes disclosed herein can be conducted at a temperature in a range from 10 °C to 75 °C, this range should be interpreted as encompassing temperatures in a range from “about” 10 °C to “about” 75 °C unless otherwise stated.

[0034] Values or ranges may be expressed herein as “about,” from “about” one particular value, and / or to “about” another particular value. When such values or ranges are expressed, other embodiments disclosed include the specific value recited, from the one particular value, and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that there are a number of values disclosed therein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. In another aspect, each use of the term “about” can, independently, mean +20% of the stated value, ±15% of the stated value, ±10% of the stated value, ±5% of the stated value, or ±3% of the stated value.

[0035] Applicants reserve the right to proviso out or exclude any individual members of any such group of values or ranges, including any sub-ranges or combinations of sub-ranges within the group, that can be claimed according to a range or in any similar manner, if for any reason Applicants choose to claim less than the full measure of the disclosure, for example, to account for a reference that Applicants can be unaware of at the time of the filing of the application. Further, Applicants reserve the right to proviso out or exclude any individual substituents, analogs, compounds, ligands, structures, or groups thereof, or any members of a claimed group, if for any reason Applicants choose to claim less than the full measure of the disclosure, for example, to account for a reference or prior disclosure that Applicants can be unaware of at the time of the filing of the application.

[0036] For any particular compound or group disclosed herein, any name or structure (general or specific) presented is intended to encompass all conformational isomers,regioisomers, stereoisomers, and mixtures thereof that can arise from a particular set of substituents, unless otherwise specified. The name or structure also encompasses all enantiomers, diastereomers, and other optical isomers (if there are any) whether in enantiomeric or racemic forms, as well as mixtures of stereoisomers, as would be recognized by a skilled artisan, unless otherwise specified. For example, a general reference to a “Ce alkane,” “hexane” or “hexanes” includes n-hexane, 2-methylpentane, 3 -methylpentane, 2, 2-di methylbutane, and 2,3-dimethylbutane; and a general reference to a “C4 alkyl” or “butyl group” includes an / / -butyl group, a .see -butyl group, an zso-butyl group, and a / -butyl group.

[0037] The term “substituted” when used to describe a group, for example, when referring to a substituted analog of a particular group, is intended to describe the compound or group wherein any non-hydrogen moiety formally replaces hydrogen in that group or compound, and is intended to be non-limiting. A compound or group can also be referred to herein as “unsubstituted” or by equivalent terms such as “non-substituted,” which refers to the original group or compound. “Substituted” is intended to be non-limiting and include inorganic substituents or organic substituents as specified and as understood by one of ordinary skill in the art.

[0038] The terms “contact product,” “contacting,” and the like, are used herein to describe compositions and methods wherein the components are contacted together in any order, in any manner, and for any length of time, unless specified otherwise. For example, the components can be contacted by blending or mixing. Further, unless otherwise specified, the contacting of any component can occur in the presence or absence of any other component of the compositions and methods described herein. Combining additional materials or components can be done by any suitable method. Further, the term “contact product” includes mixtures, blends, solutions, slurries, reaction products, and the like, or combinations thereof. Although “contact product” can, and often does, include reaction products, it is not required for the respective components to react with one another. Similarly, “contacting” two or more components can result in a reaction product or a reaction mixture. Consequently, depending upon the circumstances, a “contact product” can be a mixture, a reaction mixture, or a reaction product.

[0039] The term “alkyl group” is used herein in accordance with the definition specified by IUPAC: a univalent group formed by removing a hydrogen atom from an alkane. The alkyl group may be linear or branched unless otherwise specified.

[0040] A “cycloalkane” is used herein to refer to a saturated cyclic hydrocarbon, with or without side chains, for example, cyclobutane, cyclopentane, cyclohexane, methyl cyclopentane, and methyl cyclohexane. Other identifiers may be utilized to indicate the presence of particular groups, if any, in the cycloalkane (for example, halogenated cycloalkane indicates the presence of one or more halogen atoms replacing an equivalent number of hydrogen atoms in the cycloalkane).

[0041] The term “hydrocarbyl group” is used herein in accordance with the definition specified by IUPAC: a univalent group formed by removing a hydrogen atom from a hydrocarbon (that is, a group containing only carbon and hydrogen). Thus, a hydrocarbyl group includes alkyl groups (linear or branched), cycloalkyl groups, alkenyl groups, aryl groups, and the like. Non-limiting examples of hydrocarbyl groups include methyl, ethyl, butyl, hexyl, phenyl, tolyl, propenyl, and the like.

[0042] When used herein with regard to the selection of a substituent, the term “independently” indicates that two differently labeled substituents, e.g., R1and R2, selected from the same pool of substituents may be the same or different.

[0043] The Abstract of this application is not intended to be used to construe the scope of the claims or to limit the scope of the subject matter that is disclosed herein, but rather to satisfy the requirements of 37 C.F.R. § 1.72(b), to enable the United States Patent and Trademark Office and the public generally to determine quickly from a cursory inspection the nature and gist of the technical disclosure. Moreover, any headings that are employed herein are also not intended to be used to construe the scope of the claims or to limit the scope of the subject matter that is disclosed herein.

[0044] All publications and patents mentioned herein are incorporated herein by reference in their entireties for the purpose of describing and disclosing, for example, the constructs and methodologies that are described in the publications, which might be used in connection with the presently described invention. The publications discussed throughout the text are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the inventors are not entitled to antedate such disclosure by virtue of prior invention.

[0045] Those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments disclosed herein without materially departing from thenovel teachings and advantages according to this disclosure. Accordingly, all such modifications and equivalents are intended to be included within the scope of this disclosure as defined in the following claims. Therefore, it is to be understood that resort can be had to various other aspects, embodiments, modifications, and equivalents thereof which, after reading the description herein, may suggest themselves to one of ordinary skill in the art without departing from the spirit of the present disclosure or the scope of the appended claims.DETAILED DESCRIPTION

[0046] The present disclosure is directed to odorants, odorant compositions, and methods of odorizing materials, such as fluids, which can include a fuel gas.

[0047] ODORANTS

[0048] Compounds are provided herein, such as odorants for a fluid. The odorants can be non-toxic (e.g., to humans or mammals) or have a detectable odor below a toxicity level. The compounds can be non-toxic (e.g., to humans or mammals) or have a detectable odor below a toxicity level. The compounds can be environmentally benign by not posing health or toxicity concerns to human or biological species. Combustion products of the compounds also can be environmentally benign. The compounds can be benign to the components of a device system or apparatus, such as a pipeline, combustion system, fuel cell, or any other system, apparatus, or process.

[0049] In some embodiments, the compound includes a terminal alkene. The phrase “terminal alkene” generally refers to organic compounds, including substituted derivatives of organic compounds and / or heteroatom-containing organic compounds, that include a terminal double bond, as depicted in the following moiety:

[0050] The term “substituted derivatives” of organic compounds, including terminal alkenes, can include compounds with organic or inorganic substituents. In some embodiments, the substituted derivatives of organic compounds include an oxygen substituent.

[0051] A terminal alkene can include a heteroatom, such as oxygen, nitrogen, etc. When a terminal alkene includes oxygen as a heteroatom, the oxygen can be present as part of an ether moiety.

[0052] In some embodiments, the terminal alkene includes a terminal C3-C20 alkene, a terminal C3-C19 alkene, a terminal C3-C18 alkene, a terminal C3-C17 alkene, a terminal C3-C16 alkene, a terminal C3-C15 alkene, a terminal C3-C14 alkene, a terminal C3-C13 alkene, a terminal C3-C12 alkene, a terminal C3-C11 alkene, a terminal C3-C10 alkene, a terminal C3-C9 alkene, a terminal C3-C alkene, or a terminal C3-C7 alkene. In some embodiments, the terminal alkene is hep-l-tene (1-heptene), hex-l-ene (1-hexene), or oct-l-ene (1-octene).

[0053] In some embodiments, the compound can include a hexene, a heptene, an octene, or a combination thereof. The term “heptene” refers to a compound that includes at least one double bond and a linear chain of seven carbon atoms, wherein at least two of the seven carbon atoms are bonded to each other via a double bond, and includes substituted derivatives thereof. The term “octene” refers to a compound that includes at least one double bond and a linear chain of eight carbon atoms, wherein at least two of the eight carbon atoms are bonded to each other via a double bond, and includes substituted derivatives thereof. The substituted derivatives of heptene and octene can include, but are not limited to, a C1-C2 substituted heptene or a C1-C2 substituted octene. The substituted derivatives of the heptene and octene can include, but are not limited to, a C1-C2 substituted heptene or a C1-C2 substituted octene. As an example, the following table shows a generic schematic of a linear chain of seven carbon atoms, an embodiment of a heptene, and an embodiment of a Ci substituted heptene.

[0054] A terminal alkene can include one or more double bonds. When a terminal alkene includes two double bonds, the compound can be referred to as a “diene.” In some embodimentsthe diene includes a hexadiene or an octadiene. The term “hexadiene” refers to a compound that includes at least two double bonds and a linear chain of six carbon atoms, wherein at least four of the six carbon atoms are bonded to each other via a double bond, and includes substituted derivatives thereof. In some embodiments, the hexadiene includes hexa-l,5-diene, where 1,5 refers to the first and second and fifth and sixth carbons, respectively, of the linear chain of six carbon atoms that are bonded to each other via a double bond. In some embodiments, the octadiene includes octa-1, 7-diene, where 1,7 refers to the first and second and seventh and eighth carbons, respectively, of the linear chain of eight carbon atoms that are bonded to each other via a double bond. Substituted derivatives of hexadiene or octadiene can include, but are not limited to, a C1-C2 substituted hexadiene or a C1-C2 substituted octadiene.

[0055] In some embodiments, the terminal alkene includes buta-l,3-diene (1,3- butadiene). In some embodiments, the terminal alkene includes hexa-l,5-diene (1,5-hexadiene). In some embodiments, the terminal alkene includes hepta- 1,6-diene (1,6-heptadiene). In some embodiments, the terminal alkene includes octa-1, 7-diene (1,7-octadiene).

[0056] In some embodiments, the terminal alkene includes a compound of formula (A): CH2=CH(CH2)mCH=CH2formula (A); wherein m is an integer selected from 0 to 4.

[0057] In some embodiments, the heptadiene and / or the octadiene includes a compound of formula (B):CH3CH=CH(CH2)mCH=CH2formula (B); wherein m is an integer selected from 0 to 4, such as 2 or 3 (e.g., m is 2 for a heptadiene and 3 for an octadiene).

[0058] In some embodiments, the heptadiene and / or the octadiene includes a compound of formula (C):CH3(CH2)mCH=CH(CH2)nCH=CH3formula (C); wherein m and n, independently, are an integer from 0 to 4; wherein, in some embodiments, m is 0, 1, 2, or 3, and n is 0, 1, 2, or 3; wherein, for example, m + n = 2 for heptadienes, and m + n = 3 for octadienes.

[0059] In some embodiments, a terminal alkene includes a compound of formula (D): R1-(CH2)n-C=CH2; formula (D);wherein n is an integer selected from 0 to 5, or 0 to 4; and wherein R1is selected from hydrogen, a Ci-Ce alkyl, such as methyl, ethyl, propyl, isopropyl, isobutyl, tert-butyl, etc. Alternatively, R1can be selected from a C3-C12 cycloalkyl, a C3-C10 cycloalkyl, or a C3-C7 cycloalkyl, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc.

[0060] In some embodiments, the compound includes a terminal alkyne. The phrase “terminal alkyne” generally refers to organic compounds, including substituted derivatives of organic compounds and / or heteroatom-containing organic compounds, that include a terminal triple bond, as depicted in the following moiety:

[0061] The term “substituted derivatives” of organic compounds, including terminal alkynes, can include compounds with organic or inorganic substituents. In some embodiments, the substituted derivatives of organic compounds include an oxygen substituent.

[0062] In some embodiments, the terminal alkyne includes a terminal C3-C20 alkyne, a terminal C3-C19 alkyne, a terminal C3-C18 alkyne, a terminal C3-C17 alkyne, a terminal C3-C16 alkyne, a terminal C3-C15 alkyne, a terminal C3-C14 alkyne, a terminal C3-C13 alkyne, a terminal C3-C12 alkyne, a terminal C3-C11 alkyne, a terminal C3-C10 alkyne, a terminal C3-C9 alkyne, a terminal C3-C8 alkyne, or a terminal C3-C7 alkyne.

[0063] A terminal alkyne can be referred to as a “1 -alkyne”. For example, a “heptyne” can include a 1-heptyne (e.g., hept-l-yne), a 2-heptyne (e.g., hept-2-yne), a 3-heptyne (e.g., hept- 3-yne), or combinations thereof. A terminal alkyne can be a linear terminal alkyne (e.g., but-1- yne), or a branched (e.g., bulky) terminal alkyne, which contains a branched terminal alkyne (e.g., 4-methylpent-l-yne) or a cycloalkane terminal alkyne (e g., cyclopropylacetylene).

[0064] A terminal alkyne can include two or more triple bonds, one or more double bonds, or a combination thereof. When a terminal alkyne includes at least one triple bond and at least one double bond, the compound can be referred to as an “enyne.” A number of enynes are provided herein, such as but-l-en-3-yne. A double bond of an enyne can be a terminal double bond or a non-terminal double bond. When a terminal alkyne includes two triple bonds, the compound can be referred to as a “diyne.” A diyne can include two terminal triple bonds, or one terminal triple bond and one non-terminal triple bond.

[0065] A terminal alkyne can include a heteroatom, such as oxygen, nitrogen, etc. When a terminal alkyne includes oxygen as a heteroatom, the oxygen can be present as part of an ether moiety.

[0066] In some embodiments, the odorants include a hexyne, a heptyne, an octyne, or a combination thereof. The term “heptyne” refers to a compound that includes at least one triple bond and a linear chain of seven carbon atoms, wherein at least two of the seven carbon atoms are bonded to each other via a triple bond, and includes substituted derivatives thereof. The term “octyne” refers to a compound that includes at least one triple bond and a linear chain of eight carbon atoms, wherein at least two of the eight carbon atoms are bonded to each other via a triple bond, and includes substituted derivatives thereof. The substituted derivatives of the heptyne and octyne can include, but are not limited to, a C1-C2 substituted heptyne or a C1-C2 substituted octyne. As an example, the following table shows a generic schematic of a linear chain of seven carbon atoms, an embodiment of a heptyne, and an embodiment of a Ci substituted heptyne:

[0067] In some embodiments, the heptyne includes a 2-heptyne, a 3 -heptyne, or a combination thereof. The terms “2-heptyne” and “3 -heptyne”, as used herein, refer to heptynes in which the (i) second and third carbons, or (ii) the third and fourth carbons, respectively, of the linear chain of seven carbon atoms are bonded to each other via a triple bond. In some embodiments, the octyne includes a 3 -octyne, a 4-octyne, or a combination thereof. The terms “3-octyne” and “4-octyne”, as used herein, refer to octynes in which (i) the third and fourthcarbons, or (ii) the fourth and fifth carbons, respectively, of the linear chain of eight carbon atoms are bonded to each other via a triple bond.

[0068] The alkyne odorant often can comprise at least 90 mol% of a Ce-Cs alkyne, and more often, at least 95 mol%, at least 97 mol%, at least 98 mol%, or at least 99 mol% of the C&- Cs alkyne. For instance, the alkyne odorant can comprise hex-l-yne, hex-2-yne, hept-2-yne, or a combination thereof; alternatively, hex-l-yne; alternatively, hex -2-yne; or alternatively, hept-2- yne.

[0069] In some embodiments, a terminal alkyne includes a compound of formula (I): ^-(CH^-OC-H; formula (I); wherein n is an integer selected from 0 to 5, or 0 to 4; and wherein R1is selected from hydrogen, a Ci-C6alkyl, such as methyl, ethyl, propyl, isopropyl, isobutyl, tert-butyl, etc. Alternatively, R1can be selected from a C3-C12 cycloalkyl, a C3-C10 cycloalkyl, or a C3-C7 cycloalkyl, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc.

[0070] In some embodiments, the terminal alkyne includes a compound of formula (II): R2-(CH2)n-O-(CH2)m-C=C-H; formula (II); wherein n is an integer selected from 0 to 5, or 0 to 4; wherein m is an integer selected from 0 to 5, or 0 to 4; and wherein R2is selected from hydrogen or a Ci-Ce alkyl, such as methyl, ethyl, propyl, isopropyl, isobutyl, tert-butyl, etc.

[0071] In some embodiments, the terminal alkyne includes a compound of formula (III): H-C=C-(CH2)n-C=C-H; formula (III); wherein n is an integer selected from 0 to 5, or 0 to 4.

[0072] In some embodiments, the terminal alkyne includes a compound of formula (IV): H-C=C-(CH2)n-O-(CH2)ra-C=C-H; formula (IV); wherein n is an integer selected from 0 to 5, or 0 to 4; and wherein m is an integer selected from 0 to 5, or 0 to 4.

[0073] In some embodiments, the terminal alkyne includes a compound of formula (V): H-CH-CH-(CH2)11-C =C-H; formula (V); wherein n is an integer selected from 0 to 5, 0 to 4, or 1 to 4.

[0074] In some embodiments, the terminal alkyne includes a compound of formula (VI): formula (VI);wherein n is an integer selected from 0 to 5, or 0 to 4; and wherein R3is hydrogen or a Ci-Ce alkyl, such as methyl, ethyl, propyl, isopropyl, isobutyl, tert-butyl, etc.

[0075] In some embodiments, the terminal alkyne includes a compound of formula (VII): R4-CH=CH-(CH2)n-C=C-H; formula (VII); wherein n is an integer selected from 0 to 5, or 0 to 4; and wherein R4is hydrogen or a Ci-Ce alkyl, such as methyl, ethyl, propyl, isopropyl, isobutyl, tert-butyl, etc.

[0076] In some embodiments, an alkyne, such as an odorant or a terminal alkyne whenR5or R6is hydrogen, includes a compound of formula (VIII):R5-C=C-R6; formula (VIII); wherein R5and R6, independently, are hydrogen, a Ci-Ce alkyl, or a Ci-Ce cycloalkyl. The Ci-Ce alkyl can include methyl, ethyl, propyl, isopropyl, isobutyl, tert-butyl, etc.

[0077] In some embodiments, the heptyne and / or the octyne includes a compound of formula (IX):CH3-(CH2)m-C=C-(CH2)n-CH3 formula (IX); wherein m is 2 or 3; n is 0 or 1; and m + n = 3 or 4 (e.g., m + n = 3 for heptynes, and m + n = 4 for octynes).

[0078] In some embodiments, the heptyne and / or the octyne includes a compound of formula (X):(CH3)2CH-(CH2)m-C=C-(CH2)n-CH3formula (X); wherein m is 1 or 2; n is 0 or 1; and m + n = 2 or 3 (e g., m + n = 2 for heptynes, and m + n = 3 for octynes).

[0079] In some embodiments, the heptyne and / or the octyne includes a compound of formula (XI):(CH3)3C-(CH2)m-C=C-(CH2)n-CH3 formula (XI); wherein m is 1 or 2; n is 0 or 1; and m + n = 2 or 3 (e.g., m + n = 2 for heptynes, and m + n = 3 for octynes).

[0080] In some embodiments, the terminal alkene, terminal alkyne, or non-terminal alkyne (such as a compound of formula (VIII) when R or R6is hydrogen) includes one or more of the following compounds:

[0081] ODORANT COMPOSITIONS

[0082] Also provided herein are odorant compositions. In some embodiments, the odorant compositions include any one or more odorants provided herein and an additive. The additive can be dispersed in the odorant, or vice versa, depending, for example, on whether the additive or the odorant, respectively, is the majority component.

[0083] The additives for the odorant compositions (and odorized fluid compositions) provided herein can include a stabilizer, an antioxidant, a radical inhibitor, or a combination thereof. In some embodiments, the additive is capable of reacting with an odorant poison (such as oxygen (O2), ozone, superoxide anion (Ch’), organic peroxide (ROOR’), organic peroxy radical (ROO»), organic hydroperoxide (ROOH), hydroxyl radical (RO*), inorganic peroxide, hydrogen peroxide, metal oxide, peroxynitrite (ONOO’), nitric oxide (*NO), etc.), thereby avoiding or reducing the likelihood of the (i) formation of one or more undesired products, (ii) polymerization of the odorant, (iii) decomposition of the odorant, or (iv) a combination thereof. The additive, such as a radical inhibitor, can have a reactivity towards the odorant poison that is greater than its reactivity towards the odorant. For example, phenolic derivatives exhibit antioxidant properties through two key mechanisms. In Hydrogen Atom Transfer (HAT), phenolic antioxidants can donate a hydrogen atom to free radicals, neutralizing them and preventing oxidative damage of alkynes. This process stabilizes the free radicals by converting them into less reactive species. In Single Electron Transfer (SET), phenolic compounds transfer an electron to free radicals, reducing them and stopping the chain reaction of oxidation. This helps reduce the autocatalytical nature of the alkyne oxidation process. Amine derivatives act as antioxidants primarily by neutralizing free radicals, which are highly reactive molecules that can cause oxidative damage to compounds such as alkynes through three key mechanisms. By free radical scavenging, amines, particularly aromatic amines, are effective at scavenging free radicals. They donate hydrogen atoms to free radicals, thereby neutralizing them and preventing further oxidative reactions. Some amines can also decompose hydroperoxides, which are intermediates in the oxidation process. This helps to break down potentially harmful compounds before they can cause damage to compounds such as alkynes. Hindered amines, such as those derived from 2,2,6,6-tetramethylpiperidine, are particularly effective in protecting materials against UV light degradation. They work by neutralizing free radicals formed during UV exposure. Organic acids, such as citric acid, malic acid, and tartaric acid, can act as antioxidants and protect organic compounds from oxidation through two key mechanisms. Organic acids canneutralize free radicals, which are unstable molecules that can cause oxidative damage organic compounds. By donating an electron to these free radicals, organic acids stabilize them and prevent them from causing further damage to compounds such as alkynes. Some organic acids can bind to metal ions impurities like iron and copper, which catalyze oxidative reactions. This reduces the availability of the metal ions to participate in oxidation reactions, thereby protecting other organic compounds such as alkynes. Other compounds are chemically converted, such as for example, isopropanol which can react with oxidative species to form acetone, thus avoiding the oxidation of the alkyne moiety. Other mechanisms and properties of the additives are envisioned. This can include for example the reaction of the odorant with an odorant poison catalyzed by the equipment surfaces such as storage tank (e.g. metal or alloy and corresponding oxides surfaces), seals (e.g. organic elastomers), and plastic parts (e.g. resin or processing additives included in the plastic parts).

[0084] The additive can improve the stability of an odorant, such as any of those described herein. For example, an odorant composition or odorized fluid provided herein can be stored (i) for at least 1 month, 6 months, 12 months, 18 months, 24 months, 30 months, 36 months, 42 months, 48 months, 54 months, or 60 months, (ii) at a temperature of at least -40 °C, at least -30 °C, at least -20 °C, at least -10 °C, at least 0 °C, at least 10 °C, at least 15 °C, at least 20 °C, at least 25 °C, at least 35 °C, at least 45 °C, at least 50 °C, at least 55 °C, at least 60 °C, at least 65 °C, at least 70 °C, at least 75 °C, at least 80 °C, at least 85 °C, or at least 90 °C, or (iii) a combination thereof, and during the storing of the odorant composition or the odorized fluid less than 10 mol%, less than 5 mol%, less than 1 mol%, or less than 0.1 mol% of the odorant polymerizes. As a further example, an odorant composition or odorized fluid provided herein can be stored (i) for at least 1 month, 6 months, 12 months, 18 months, 24 months, 30 months, 36 months, 42 months, 48 months, 54 months, or 60 months, (ii) at a temperature of at least -40 °C, at least -30 °C, at least -20 °C, at least -10 °C, at least 0 °C, at least 10 °C, at least 15 °C, at least 20 °C, at least 25 °C, at least 35 °C, at least 45 °C, at least 50 °C, at least 55 °C, at least 60 °C, at least 65 °C, at least 70 °C, at least 75 °C, at least 80 °C, at least 85 °C, or at least 90 °C, or (iii) a combination thereof, and during the storing of the odorant composition or the odorized fluid less than 10 mol%, less than 5 mol%, less than 1 mol%, or less than 0.1 mol% of the odorant reacts with oxygen, ozone, a peroxide, a hydroxyl, a hydroxyl radical, a metal oxide, a superoxide anion (O2 ) to form an oxygenated product.

[0085] The additive can be a non-odiferous compound or an odiferous compound.Examples of odiferous additives include but are not limited to cyclobutanol, 2,4-dimethylpentan- 3-one, 2-methyl-l -pentanol, 4-methyl-2-pentanol, isopropyl ether, 2,2-dimethylbutanol, isoamyl alcohol (isopentanol), 2-methyl-l -butanol, (S)-(+)-4-methyl-2-pentanol, (2R)-2,3-dimethylbutan- l-ol, (2R)-2-methylpentan-l-ol, 2,3-dimethylbutan-l-ol, 3-methylhexan-2-ol, 2,3-dimethyl-2- pentanol, 3-methylpentan-2-ol, 2-methylpentan-3-ol, 3 -methyl-(R)-3 -hexanol, 3 -pentanol, 2- methylpentan-2-ol, 2,3-dimethylbutan-2-ol, 3-methyl-3-hexanol, 2,4-dimethyl-3-pentanol, 2- pentanol, 3-ethyl-2-pentanol, 4,4-dimethylpentan-2-ol, 4-methylhexan-3 -ol, 2-methylhexan-3-ol, 3-hexanol, 3, 3 -dimethyl -1 -butanol, 2,4-dimethylpentan-2-ol, 2-methylhexan-2-ol, isopropyl alcohol, 2-methyl-(3S)-3-pentanol, propanol, 1-butanol, 1-pentanol, 2-methyl-2-butanol, 2- methyl-1 -propanol (isobutanol), 2-butanol, (2R)-4,4-dimethylpentan-2-ol, 2- methyltetrahydrofuran, cis-2-penten-l-ol, l-hexen-3-ol, 3-methyl-2-buten-l-ol, 3-buten-2-ol, 3- (1 -methylethoxy)-! -propene, l-penten-3-ol, 2-ethyl -5 -methylfuran, 2-ethylfuran, 2-methylfuran, acetal, butyl ether, methyl tert-butyl ether, 1, 1 -dimethoxy ethane, 1 -methoxy-cyclohexene, 4- methoxy-2-methyl-l -butene, 3 -methoxy- 1 -propene, pentanal (valeraldehyde), cyclobutanone, 2- methylpentanal, propanal (propionaldehyde), butanal (butyraldehyde), 2,2- dimethylvaleraldehyde, 3-methylvaleraldehyde, (3S)-3-methylpentanal, 2-ethylpentanal, 2- methyl-(R)-pentanal, 3 -methylbutanal (isovaleraldehyde), hexanal (n-hexylaldehyde), 2- methylpropanal (isobutyraldehyde), (2S)-2-methylpentanal, 2-ethylbutanal, butyl formate, cyclopentyl formate, 3-methyl-2-butenal, tiglic aldehyde, trans-2-butenal, 2-pentenal, 4-pentenal, (4E)-4-hexenal, 3-hexenal, hexenal, 4-methyl -2-pentenal, 2-methyl-2-pentenal, (2E)-2-hexenal, (3Z)-3-hexenal, 1-butene, 2,4,4- trimethyl- 1 -pentene, 2,4,4- trimethyl-2-pentene, 1-pentene, 1- octene, 2-octene, 1-nonene, (E)-2-octene, 1,3 -pentadiene, 2,3-dimethyl-l, 3-butadiene, 2,3,4- trimethyl-2-pentene, 1-hexene, 1,5-hexadiene, 1,4-hexadiene, 3-methyl-l, 2-butadiene, 1,5- hexadien-3-ol, cyclohexene, cyclopentene, 5-ethylidene-2-norbomene, ethyl propionate, ethyl butyrate, propyl butyrate, propyl propionate, methyl hexanoate (methyl caproate), ethyl isovalerate, methyl 3 -methyl valerate, ethylpivalate, ethyl valerate, isobutyl propionate, tert-butyl acetate, methyl isobutyrate (methyl 2-methyl propanoate), methyl propionate, methyl isovalerate, butyl propionate, methyl butyrate, methyl valerate, isopropyl propionate, isopropyl butyrate, propyl isobutyrate, propan-2-yl, (2S)-2-methylbutanoate, ethyl 2-methylbutyrate, methyl 2- methylbutyrate, ethyl isobutyrate, isobutyl isobutyrate, butan-2-yl propanoate, isopropylisobutyrate, vinyl propionate, iso-butyl acrylate, n-butyl acrylate, 4-pentenyl acetate, allyl propionate, 3-butenoic acid, methyl ester, methyl methacrylate, ethyl methacrylate, (E)-2- butenoic acid methyl ester, 4-methylhexan-2-one, 2-pentanone, 5-methyl-2-hexanone (methyl isoamyl ketone), 2-heptanone (methyl n-amyl ketone), 4-heptanone, 3-methylhexan-2-one, 2,2- dimethyl-3 -hexanone, 3-methyl-2-butanone, 2, 2-dimethyl-3 -pentanone, 3-hexanone, 4,4- dimethyl-2-pentanone, 2-hexanone, 3-ethyl-2-pentanone, 5-methylhexan-3-one, 2-methyl-3- hexanone, 2-butanone, 3-pentanone, sec-butyl acetate, isopropyl acetate, sec-amyl acetate, 1- Methoxy-2-propyl acetate, propyl acetate, isobutyl acetate, butyl acetate, isopentyl acetate (isoamyl acetate), ethyl acetate, methyl butyl acetate, (2S)-2-methylbutyl acetate, isopropenyl acetate, mesityl oxide, l-penten-3-one (ethyl vinyl ketone), l-hexen-3-one (vinyl propyl ketone), 2-Hexen-4-one, l-hepten-3-one (vinyl butyl ketone), 4-methyl-4-penten-2-one, 3-methyl-3- penten-2-one,3-penten-2-one, 2-methylphenol (o-cresol), 3 -methylphenol (m-cresol), 4- methylphenol (p-cresol), 2-ethylphenol, 3 -ethylphenol, 4-ethylphenol, 2-propylphenol, 3- propylphenol, 4-propylphenol, 2-butylphenol, 3 -butylphenol, 4-butylphenol, 2-methoxyphenol (guaiacol), 3 -methoxyphenol, 4-methoxyphenol or 4-Hydroxyanisole or hydroquinone monomethyl ether also known as MeHQ, 2 -ethoxy phenol, 3-ethoxyphenol, 4-ethoxyphenol, 2- methoxy-3 -methylphenol, 4-methoxy-3 -methylphenol, 2-methoxy-4-methylphenol (creosol), 3- methoxy-4-methylphenol, 2-methoxy-5-methylphenol (isocreosol), 3-methoxy-5-methylphenol, 2-hydroxybenzoic acid or salicylic acid, 3 -hydroxybenzoic acid, 4-hydroxy benzoic acid, 2- hydroxybenzoic acid methyl ester or methyl salicylate or wintergreen oil, 3-hydroxybenzoic acid methyl ester, 4-hydroxybenzoic acid methyl ester, 2-hydroxybenzoic acid ethyl ester or ethyl salicylate, 3-hydroxybenzoic acid ethyl ester, 4-hydroxybenzoic acid ethyl ester, 2,3- dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 3,4- dimethylphenol, 3,5-dimethylphenol, 2-chlorophenol, 3 -chlorophenol, 4-chlorophenol, 2- fluorophenol, 3 -fluorophenol, 4-fluorophenol, 2-(trifluoromethyl)phenol, 3- (trifluoromethyl)phenol, 4-(trifluoromethyl)phenol, 2,4-dinitrophenol (DNP), 2,4-dinitro-6-sec- butyl-phenol (DNBP) and 2,6-dinitro-p-cresol, benzene- 1 ,2-diol (pyrocatechol), benzene- 1,3- diol (resorcinol), benzene- 1,4-diol (hydroquinone, HQ), 3,4,5-trihydroxybenzoic acid or gallic acid, 3,4,5-trihydroxybenzoic acid methyl ester or methyl gallate, 3,4,5-trihydroxybenzoic acid ethyl ester or ethyl gallate, 3,4,5-trihydroxybenzoic acid propyl ester or propyl gallate, 3,4,5- trihydroxybenzoic acid octyl ester or octyl gallate, dimethylhydroxylamine, trimethylamine,tri methyl amine N-oxide, diethylamine, diethylhydroxylamine, triethylamine, triethylamine N- oxide, dipropylamine, dipropylhydroxylamine, tripropylamine, tripropylamine N-oxide, diisopropylamine, diisopropylhydroxylamine, triisopropylamine, triisopropylamine N-oxide, dibutylamine, dibutylhydroxylamine, tributylamine, tributylamine N-oxide, diisobutylamine, diisobutylhydroxylamine, tri-iso-butylamine, tri-iso-butylamine N-oxide, di-tert-butylamine, di- tert-butylhydroxylamine, tri-tert-butylamine, tri-tert-butylamine N-oxide, diethylmethylamine, dipropylmethylamine, diisopropylmethylamine, dipropylethylamine, diisopropylethylamine, ethanolamine, diethanolamine, triethanolamine, N,N-dimethylisopropanolamine (DMPA), 2,2,6,6-tetramethylpiperidine, aniline, N,N-dimethyl aniline, and N,N-diethylaniline.

[0086] An odiferous additive can contribute to the alarming scent of an odorized fluid. As a result, when an additive is an odiferous additive, a concentration of odorant that is used in an odorized fluid or an odorant composition can be reduced without undesirably impacting the detectability of the odorized fluid.

[0087] The additive generally can be any compound that is capable of acting as a stabilizer, an antioxidant, and / or a radical inhibitor, especially for an odorant that includes an alkynyl moiety. As used herein, the term “stabilizer, antioxidant, and / or radical inhibitor” refers to a compound or material that prevents or delays the chemical degradation of a fluid and / or an odorant compound, such as an alkyne.

[0088] When the compositions disclosed herein (e.g., odorized fluid compositions) contain an additive, and the additive comprises a stabilizer, an antioxidant, and / or a radical inhibitor, the additive can be present in the composition in any suitable amount. In some embodiments, the additive (stabilizer, antioxidant, and / or radical inhibitor) is present in the composition at a concentration of about 10 ppmw (ppm by weight) to about 10 wt%, about 10 ppmw to about 8 wt%, about 10 ppmw to about 6 wt%, about 10 ppmw to about 4 wt%, about 10 ppmw to about 2 wt%, about 10 ppmw to about 1 wt%, about 10 ppmw to about 5,000 ppmw, about 50 ppmw to about 10 wt%, about 50 ppmw to about 8 wt%, about 50 ppmw to about 6 wt%, about 50 ppmw to about 4 wt%, about 50 ppmw to about 2 wt%, about 50 ppmw to about 1 wt%, about 50 ppmw to about 5,000 ppmw, about 50 ppmw to about 1,000 ppmw, about 200 ppmw to about 10 wt%, about 200 ppmw to about 8 wt%, about 200 ppmw to about 6 wt%, about 200 ppmw to about 4 wt%, about 200 ppmw to about 2 wt%, about 200 ppmw to about 1 wt%, about 200 ppmw to about 5,000 ppmw, or about 200 ppmw to about 2,000 ppmw, based onthe weight of the odorant in the composition). More often, the additive (stabilizer, antioxidant, and / or radical inhibitor) is present in the composition at a concentration of about 10 ppmw (ppm by weight) to about 1,000 ppmw, about 10 ppmw to about 900 ppmw, about 10 ppmw to 750 ppmw, about 10 ppmw to about 500 ppmw, about 50 ppmw to about 1,000 ppmw, about 50 ppmw to 750 ppmw, about 50 ppmw to about 500 ppmw, about 200 ppmw to about 1,000 ppmw, about 200 ppmw to about 900 ppmw, about 200 ppmw to 750 ppmw, or about 200 ppmw to about 500 ppmw, based on the weight of the odorant in the composition.

[0089] Examples of stabilizers, antioxidants, and radical inhibitors include phenolic derivatives including but not limited to, 2-methylphenol (o-cresol), 3 -methylphenol (m-cresol), 4-methylphenol (p-cresol), 2-ethylphenol, 3 -ethylphenol, 4-ethylphenol, 2-propylphenol, 3- propylphenol, 4-propylphenol, 2-butylphenol, 3 -butylphenol, 4-butylphenol, 2-methoxyphenol (guaiacol), 3-methoxyphenol, 4-methoxyphenol or 4-hydroxy anisole or hydroquinone monomethyl ether (also known as MeHQ), 2-ethoxyphenol, 3-ethoxyphenol, 4-ethoxyphenol, 2- methoxy-3 -methylphenol, 4-methoxy-3 -methylphenol, 2-methoxy-4-methylphenol (creosol), 3- methoxy -4-methylphenol, 2-methoxy-5-methylphenol (isocreosol), 3-methoxy-5-methylphenol, 2,6-di-tert-butyl-4-methylphenol or butylated hydroxytoluene or tert-butyl hydroxytoluene (also known as BHT), a mixture of 2-tert-butyl-4-methoxyphenol and 3-tert-butyl-4-methoxyphenol, (l,l-dimethylethyl)-4-methoxyphenol or butylated hydroxyanisole or tert-butylhydroxyanisole (also known as BOA or BHA), 2,5-di-tert-butyl-phenol, 2,6-di-tert-butyl phenol, 2-( 1 , 1 - dimethylethyl)-!, 4-benzenediol or mono-tert-butylhydroquinone or tert-butyl hydroquinone (also known as MTBHQ or TBHQ), 2-hydroxybenzoic acid or salicylic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2-hydroxybenzoic acid methyl ester or methyl salicylate or wintergreen oil, 3-hydroxybenzoic acid methyl ester, 4-hydroxybenzoic acid methyl ester, 2-hydroxybenzoic acid ethyl ester or ethyl salicylate, 3-hydroxybenzoic acid ethyl ester, 4-hydroxybenzoic acid ethyl ester, 2,3-dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, 2,4,5- trimethylphenol, 2,4,6-trimethylphenol, 3,4,5-trimethylphenol, 2-chlorophenol, 3 -chlorophenol, 4-chlorophenol, 2-fluorophenol, 3-fluorophenol, 4-fluorophenol, 2-(trifluoromethyl)phenol, 3- (trifluoromethyl)phenol, 4-(trifluoromethyl)phenol, 2,4-dinitrophenol (DNP), 2,4-dinitro-6-sec- butyl-phenol (DNBP) and 2, 6-dinitro-p-cresol, catechol derivatives, including but not limited to, benzene- 1,2-diol (pyrocatechol), benzene- 1,3 -diol (resorcinol), benzene- 1,4-diol (hydroquinone,HQ), 4-tert-butylcatechol (TBC), 2, 5-Bis(l,l -dimethylethyl)-], 4-benzenediol or 2,5-di-tert- butylhydroquinone (also known as DBHQ or DTBHQ), 2-methyl-l, 4-benzenediol or tolyhydroquinone or methylhydroquinone (also known as THQ or M-HQ), 3,4,5- trihydroxybenzoic acid or gallic acid, 3,4,5-trihydroxybenzoic acid methyl ester or methyl gallate, 3,4,5-trihydroxybenzoic acid ethyl ester or ethyl gallate, 3,4,5-trihydroxybenzoic acid propyl ester or propyl gallate and 3,4,5-trihydroxybenzoic acid octyl ester or octyl gallate, amine derivatives, including but not limited to, dimethylhydroxylamine, trimethylamine, trimethylamine N-oxide, diethylamine, diethylhydroxylamine, triethylamine, triethylamine N- oxide, dipropylamine, dipropylhydroxylamine, tripropylamine, tripropylamine N-oxide, diisopropylamine, diisopropylhydroxylamine, triisopropylamine, triisopropylamine N-oxide, dibutylamine, dibutylhydroxylamine, tributylamine, tributylamine N-oxide, diisobutylamine, diisobutylhydroxylamine, triisobutylamine, triisobutylamine N-oxide, di-tert-butylamine, di-tert- butylhydroxylamine, tri-tert-butylamine, tri-tert-butylamine N-oxide, diethylmethylamine, dipropylmethylamine, diisopropylmethylamine, dipropylethylamine, diisopropylethylamine, ethanolamine, diethanolamine, triethanolamine, N,N-dimethylisopropanolamine (DMPA), 2,2,6,6-tetramethylpiperidine, 2,2,6,6-Tetramethylpiperidine N-oxide (TEMPO) and derivatives, pyridine N-oxide, N-methylmorpholine N-oxide (NMMO), lauryldimethylamine N-oxide, N,N- dimethyldodecylamine N-oxide, N,N-dimethyloctylamine N-oxide, N,N- dimethylhexadecylamine N-oxide, N-palmitoylethanolamine (PEA), N-acetylethanolamine (AEA), N-myristoylethanolamine (MEA), diphenylamine, phenyl-a-naphthylamine (PANA), N,N'-di-2-butyl-l,4-phenylenediamine (DBPDA), N,N-dibenzylhydroxylamine (DBHA), 1,4- phenylenediamine, aniline, N,N-dimethylaniline and N,N-diethylaniline, organic acids, including but not limited to, formic acid, acetic acid, benzoic acid, sorbic acid, citric acid, malic acid, tartaric acid, succinic acid, lactic acid and oxalic acid, inorganic acids and salts, including but not limited to, hypophosphorous acid, sodium metabisulfite, sodium bisulfite, sodium sulfite, sodium nitrite, sodium thiosulfate, sodium selenite, sodium hypophosphite, sodium selenate, sodium selenite, sodium hypochlorite, sodium persulfate and equivalent potassium salts, natural product derivatives, including but not limited to, ascorbic acid (vitamin C) or a derivative thereof (e.g., ascorbyl palmitate, ascorbyl acetate, etc.), a tocopherol and tocotrienols (vitamin E) or a derivative thereof (e.g., alpha-tocopherol, beta-tocopherol, gamma-tocopherol, delta-tocopherol, tocopheryl acetate, etc.), retinol (vitamin A) or a derivative thereof (e.g., retinoid acid, retinylacetate, retinyl palmitate, etc.), hydroxy cinnamates or a derivative thereof (e.g. caffeic acid, chlorogenic acid, ferulic acid, p-coumaric acid, etc.), flavonoids or a derivative thereof (taxifolin, luteolin, apigenin, tangeritin, quercetin, kaempferol, myricetin, fisetin, galangin, isorhamnetin, pachypodol, rhamnazin, pyranoflavonols, furanoflavonols, hesperetin, naringenin, eriodictyol, homoeriodictyol, cyanidin, delphinidin, malvidin, pelargonidin, peonidin, petunidin, catechin, gallocatechin, catechin 3-gallate, gallocatechin 3-gallate, epicatechins, epigallocatechin, epicatechin 3-gallate, epigallocatechin 3-gallate, etc), glutathione, melatonin and uric acid.

[0090] In some embodiments, the additive has a boiling point that is about 300 °C or less, about 270 °C or less, about 250 °C or less, about 220 °C or less, about 190 °C or less, about 160 °C or less, about 130 °C or less, about 120 °C or less, about 110 °C or less, or about 100 °C or less. In some embodiments, the additive has a freezing point that is about 100 °C or less, about 50 °C or less, about 0 °C or less, about -80 °C or less, about -70 °C or less, about -60 °C or less, about -50 °C or less, about -40 °C or less, about -30 °C or less, about -20 °C or less, or about -10 °C or less.

[0091] The additive can be a non-toxic compound. The additive also can be environmentally benign. In some embodiments, the additive has an acute oral toxicity of at least 100 mg / kg, at least 200 mg / kg, at least 300 mg / kg, at least 500 mg / kg, at least 1,000 mg / kg, at least 2,000 mg / kg, at least 3,000 mg / kg, at least 4,000 mg / kg, or at least 5,000 mg / kg.

[0092] The additive can have any volatility. The additive can be relatively volatile. In some embodiments, the additive has a vapor pressure (at 20 °C) of at least 0.001 kPa, at least 0.01 kPa, at least 0.1 kPa, or at least 1 kPa.

[0093] The additive can be a compound that includes an aldehyde moiety, such as a compound selected from ethanal, propanal, 1 -butanal, isobutanal (2-methylpropanal), pentanal (valeraldehyde), isopentanal (isovaleraldehyde or 3 -methylbutanal), 2-methylbutanal, pivaldehyde (2,2-dimethylpropanal), hexanal, 4-methylpentanal, 3-methylpentanal, 2- methylpentanal, 3, 3 -dimethylbutanal, 1 -octanal, furfural, glyoxal, or a combination thereof. In some embodiments, the additive is a C3-C10 alkyl aldehyde, a C3-C6 alkyl aldehyde, or a derivative thereof, such as a derivative comprising an alkenyl moiety, an alkynyl moiety, or a combination thereof, wherein the alkyl aldehyde is a cyclic or non-cyclic aldehyde.

[0094] The additive can be a compound that includes a ketone moiety (for example, one ketone moiety, two ketone moieties, three ketone moieties, etc.). For example, the additive caninclude a compound selected from acetone, butanone, 2-pentanone, 3-pentanone, 3-methyl-2- butanone, 2-hexanone, 3 -hexanone, 3-methyl-2-pentanone, 2-methyl-3 -pentanone, 4- methylpentanone, 3,3-dimethyl-2-butanone, 2,3-butadione, 2,3 -pentadione, 2,4-pentadione, 3- methyl-penta-2, 4-dione, cyclobutanone, cyclopentanone, cyclohexanone, methyl isobutyl ketone, or a combination thereof. In some embodiments, the compound is a C3-C10 alkyl ketone, a C3- C10 alkyl diketone, a C4-C8 alkyl ketone, a C4-C8 alkyl diketone, a C3-C6 alkyl ketone, a C3-C6 alkyl diketone, or a derivative thereof, such as a derivative comprising an alkenyl moiety, an alkynyl moiety, or a combination thereof, wherein the alkyl ketone is a cyclic alkyl ketone or a non-cyclic alkyl ketone.

[0095] The additive can be a compound that includes an alcohol moiety (e.g., one alcohol moiety, two alcohol moieties, etc.). For example, the additive can include a compound selected from methanol, ethanol, propanol, isopropanol, butanol, 2-butanol, tert-butanol, 3-methyl-2- butanol, 2-pentanol, 3-pentanol, 2-methyl-3 -pentanol, butane-2,3-diol, 1-octanol, 2,3 -pentadiol, 2,4-pentadiol, benzyl alcohol, or a combination thereof. In some embodiments, the additive includes a C1-C10 alkyl alcohol, a C1-C10 alkyl di-alcohol, a C2-C10 alkyl alcohol, a C2-C10 alkyl di-alcohol, a Ci-Ce alkyl alcohol, a Ci-Ce alkyl di-alcohol, or a derivative thereof, such as a derivative comprising an alkenyl moiety, an alkynyl moiety, or a combination thereof.

[0096] The additive can be a compound that includes an ester moiety. For example, the additive can include methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl sorbate, ethyl sorbate, propyl sorbate, isopropyl sorbate, ethyl 2- butynoate, or a combination thereof. In some embodiments, the compound is a C2 to C10 alkyl ester, a C2-C6 alkyl ester, or a derivative thereof, such as a derivative comprising an alkenyl moiety, an alkynyl moiety, or a combination thereof.

[0097] The additive can be a compound that includes an ether moiety. For example, the additive can include dimethyl ether, diethyl ether, methyl ethyl ether, dipropyl ether, methyl propyl ether, ether propyl ether, diisopropyl ether, methyl isopropyl ether, ethyl isopropyl ether, propyl isopropyl ether, methyl butyl ether, ethyl butyl ether, methyl isobutyl ether, ethyl isobutyl ether, or a combination thereof. In some embodiments, the additive includes a C1-C10 dialkyl ether, a Ci-Ce dialkyl ether, a C1-C2 dialkyl ether, or a derivative thereof, such as a derivative comprising an alkenyl moiety, an alkynyl moiety, or a combination thereof.

[0098] The additive can be an unsubstituted or substituted diphenyl ether, or an unsubstituted or substituted C1-C10 alkylphenyl ether (which can have the following structure: C1-C10 alkyl-O-Ph, wherein, optionally, the phenyl moiety is substituted).

[0099] In some embodiments, the additive is a compound that includes a cycloalkanol moiety, such as a compound selected from cyclopropanol, cyclobutanol, cyclopentanol, or a combination thereof. In some embodiments, the additive is a Cs-Cs cycloalkanol, or a C3-C4 cycloalkanol.

[0100] In some embodiments, the additive is an unsubstituted or substituted phenol, such as 2-methylphenol (o-cresol), 3 -methylphenol (m-cresol), 4-methylphenol (p-cresol), 2- ethylphenol, 3 -ethylphenol, 4-ethylphenol, 2-propylphenol, 3 -propylphenol, 4-propylphenol, 2- butylphenol, 3 -butylphenol, 4-butylphenol, 2-methoxyphenol (guaiacol), 3-methoxyphenol, 4- methoxyphenol or 4-Hydroxyanisole or hydroquinone monomethyl ether (also known as MeHQ), 2-ethoxyphenol, 3-ethoxyphenol, 4-ethoxyphenol, 2-methoxy-3 -methylphenol, 4- methoxy-3 -methylphenol, 2-methoxy-4-methylphenol (creosol), 3-methoxy-4-methylphenol, 2- methoxy-5-methylphenol (isocreosol), 3-methoxy-5-methylphenol, 2,6-di-tert-butyl-4- methylphenol or butylated hydroxy toluene or tert-butyl hydroxy toluene (also known as BHT), a mixture of 2-tert-butyl-4-methoxyphenol and 3 -tert -butyl-4-m ethoxyphenol, (1,1-dimethylethyl)- 4-methoxyphenol or butylated hydroxyanisole or tert -butylhydroxy anisole (also known as BOA or BHA), 2,5-di-tert-butyl-phenol, 2,6-di-tert-butyl phenol, 2-(l, 1 -dimethylethyl)- 1,4- benzenediol or mono-tert-butylhydroquinone or tert-butyl hydroquinone (also known as MTBHQ or TBHQ), 2-hydroxybenzoic acid or salicylic acid, 3 -hydroxybenzoic acid, 4- hydroxybenzoic acid, 2-hydroxybenzoic acid methyl ester or methyl salicylate or wintergreen oil, 3 -hydroxybenzoic acid methyl ester, 4-hydroxybenzoic acid methyl ester, 2-hydroxybenzoic acid ethyl ester or ethyl salicylate, 3 -hydroxybenzoic acid ethyl ester, 4-hydroxybenzoic acid ethyl ester, 2,6-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, 2,4,5-trimethylphenol, 2,4,6-trimethylphenol, 3,4,5-trimethylphenol, 2- chlorophenol, 3 -chlorophenol, 4-chlorophenol, 2-fluorophenol, 3 -fluorophenol, 4-fluorophenol, 2-(trifluoromethyl)phenol, 3-(trifluoromethyl)phenol, 4-(trifluoromethyl)phenol, 2,4- dinitrophenol (DNP), 2,4-dinitro-6-sec-butyl-phenol (DNBP) and 2,6-dinitro-p-cresol, benzene- 1 ,2-diol (pyrocatechol), benzene-l,3-diol (resorcinol), benzene- 1,4-diol (hydroquinone, HQ), 4- tert-butyl catechol (TBC), 2, 5-bis(l,l -dimethylethyl)- 1,4-benzenediol or 2,5-di-tert-butylhydroquinone (also known as DBHQ or DTBHQ), 2-methyl-l ,4-benzenediol or tolyhydroquinone or methylhydroquinone (also known as THQ or M-HQ), 3,4,5- trihydroxybenzoic acid or gallic acid, 3,4,5-trihydroxybenzoic acid methyl ester or methyl gallate, 3,4,5-trihydroxybenzoic acid ethyl ester or ethyl gallate, 3,4,5-trihydroxybenzoic acid propyl ester or propyl gallate and 3,4,5-trihydroxybenzoic acid octyl ester or octyl gallate, or a combination thereof.

[0101] In some embodiments, the additive is a compound that includes a carboxylic acid moiety, such as a compound selected from formic acid, acetic acid, benzoic acid, sorbic acid, citric acid, malic acid, tartaric acid, succinic acid, lactic acid, oxalic acid, or a combination thereof. In some embodiments, the additive is a C2-C10 alkyl carboxylic acid, or a derivative thereof, such as a derivative comprising an alkenyl moiety, an alkynyl moiety, or a combination thereof.

[0102] In some embodiments, the additive is an unsubstituted or substituted quinoline.

[0103] The odorized fluid composition containing the additive can be prepared in any suitable manner, but generally, involved a process that comprises contacting the fluid, the additive, and the odorant in any order or sequence. It is important that odor leaks or odor releases be avoided in the preparation of the odorized fluid composition.

[0104] In one embodiment, for instance, the odorized fluid composition is prepared by a process that comprises introducing the additive in solid form or liquid form through a first leak- tight inlet port into an odorant vessel; introducing the odorant through the first leak-tight inlet port or a second leak-tight inlet port into the odorant vessel and mixing with the additive to form an odorant composition; and discharging at least a portion of the odorant composition from the odorant vessel through a leak-tight outlet port and contacting with the fluid to form the odorized fluid composition. Mixing can be simply allowing sufficient time for the materials to combine and form a uniform composition, or a suitable agitation technique can be used. The odorant vessel can be any suitable storage tank, isotainer, drum, for example leak-free stainless stain drums commercialized by Wilhelm Schmidt GmbH, and the like.

[0105] In another embodiment, the odorized fluid composition can be prepared by a process that comprises introducing the additive in liquid form into a multiport vessel; connecting the multiport vessel to an odorant vessel containing the odorant and transferring the additive to the odorant vessel through a leak-tight inlet port and mixing the additive with the odorant to forman odorant composition; disconnecting the multiport vessel from the odorant vessel; and discharging at least a portion of the odorant composition from the odorant vessel through a leak- tight outlet port and contacting with the fluid to form the odorized fluid composition. The transfer of the additive from the multiport vessel to the odorant vessel can be accomplished by any suitable means, such as pumping, gravity driven flow, pressure driven flow, and the like. If the additive is in solid form, a concentrated solution can be prepared by combining the additive in solid form with a small amount of the odorant and introducing the concentrated solution (in liquid form) into the multiport vessel.

[0106] In other embodiments, the additive can comprise a diluent, such as a diluent for an odorant compound such as an alkyne. The additive can include a Cs-Cs saturated hydrocarbon (e.g., a pentane, a cyclopentane, a hexane, a cyclohexane, a heptane, a cycloheptane, an octane, and / or a fluorinated hydrocarbon, such as, for example, PFC-116, PFC-c216, PFC-218, or PFC- 318).

[0107] An odorant generally can be present in an odorant composition at any desirable amount. In some embodiments, the odorant is present in an odorant composition at a total amount of at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt%, based on the total weight of the odorant composition. If an odorant includes two or more compounds, such as a heptyne and an octyne, then the heptyne and the octyne can be present in the odorant composition at a total amount of at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt%, based on the total weight of the odorant composition. For example, if 20 g of a heptyne and 30 g of an octyne are present in an odorant composition having a total weight of 100 g, then the heptyne and octyne are present in the odorant composition at a total amount of 50 wt%.

[0108] An odorant composition generally can be in any phase, e.g., a liquid or gas. An odorant composition can be stored and / or used in any desirable phase.

[0109] ODORIZED FLUIDS

[0110] Also provided herein are odorized fluids (alternatively referred to as odorized fluid compositions). In some embodiments, the odorized fluids generally include (i) a fluid, suchas a gas, and (ii) any of the odorants or the odorant compositions disclosed herein. An odorant or an odorant composition can be dispersed, evenly or unevenly, in the fluid.

[0111] An odorant can be present in an odorized fluid at any desired amount. When an odorant composition is present in an odorized fluid, the odorant composition can be present at an amount that is effective to achieve in the odorized fluid a desirable concentration of the odorant. In some embodiments, an odorant is present in an odorized fluid at a concentration of 1,000 mg / m3n or less, 900 mg / m3n or less, 800 mg / m3n or less, 700 mg / m3n or less, 600 mg / m3n or less, 500 mg / m3n or less, 400 mg / m3n or less, 300 mg / m3n or less, 200 mg / m3n or less, 100 mg / m3n or less, 90 mg / m3n or less, 80 mg / m3n or less, 70 mg / m3n or less, 60 mg / m3n or less, 50 mg / m3n or less, 40 mg / m3n or less, 30 mg / m3n or less, 20 mg / m3n or less, or 10 mg / m3n or less. In some embodiments, an odorant is present in an odorized fluid at a concentration of at least 0.5 mg / m3n, at least 1 mg / m3n, at least 2 mg / m3n, at least 3 mg / m3n, at least 4 mg / m3n, at least 5 mg / m3n, at least 6 mg / m3n, at least 7 mg / m3n, at least 8 mg / m3n, at least 9 mg / m3n, or at least 10 mg / m3n.

[0112] In some embodiments, an odorant is present in an odorized fluid at a concentration of about 1 mg / m3n to about 1,000 mg / m3n, about 1 mg / m3n to about 900 mg / m3n, about 1 mg / m3n to about 800 mg / m3n, about 1 mg / m3n to about 700 mg / m3n, about 1 mg / m3n to about 600 mg / m3n, about 1 mg / m3n to about 500 mg / m3n, about 1 mg / m3n to about 400 mg / m3n, about 1 mg / m3n to about 300 mg / m3n, about 1 mg / m3n to about 200 mg / m3n, about 1 mg / m3n to about 100 mg / m3n, about 1 mg / m3n to about 90 mg / m3n, about 1 mg / m3n to about 80 mg / m3n, about 1 mg / m3n to about 70 mg / m3n, about 1 mg / m3n to about 60 mg / m3n, about 1 mg / m3n to about 50 mg / m3n, about 1 mg / m3n to about 40 mg / m3n, about 1 mg / m3n to about 30 mg / m3n, about 1 mg / m3n to about 20 mg / m3n, or about 1 mg / m3n to about 10 mg / m3n. In some embodiments, an odorant is present in an odorized fluid at a concentration of about 5 mg / m3n to about 5,000 mg / m3n, about 5 mg / m3n to about 2,500 mg / m3n, about 5 mg / m3n to about 1,000 mg / m3n, about 5 mg / m3n to about 900 mg / m3n, about 5 mg / m3n to about 800 mg / m3n, about 5 mg / m3n to about 700 mg / m3n, about 5 mg / m3n to about 600 mg / m3n, about 5 mg / m3n to about 500 mg / m3n, about 5 mg / m3n to about 400 mg / m3n, about 5 mg / m3n to about 300 mg / m3n, about 5 mg / m3n to about 200 mg / m3n, about 5 mg / m3n to about 100 mg / m3n, about 5 mg / m3n to about 90 mg / m3n, about 5 mg / m3n to about 80 mg / m3n, about 5 mg / m3n to about 70 mg / m3n, about 5 mg / m3n to about 60 mg / m3n, about 5 mg / m3n to about 50 mg / m3n, about 5 mg / m3n to about 40mg / m3n, about 5 mg / m3n to about 30 mg / m3n, about 5 mg / m3n to about 20 mg / m3n, or about 5 mg / m3n to about 10 mg / m3n. In some embodiments, the odorant is present in the odorized fluid at a concentration of about 1 mg / m3n to about 50 mg / m3n, about 1 mg / m3n to about 40 mg / m3n, about 1 mg / m3n to about 30 mg / m3n, about 1 mg / m3n to about 20 mg / m3n, about 1 mg / m3n to about 10 mg / m3n, about 2 mg / m3n to about 50 mg / m3n, about 2 mg / m3n to about 40 mg / m3n, about 2 mg / m3n to about 30 mg / m3n, about 2 mg / m3n to about 20 mg / m3n, about 2 mg / m3n to about 15 mg / m3n, about 5 mg / m3n to about 50 mg / m3n, about 5 mg / m3n to about 40 mg / m3n, about 5 mg / m3n to about 30 mg / m3n, about 5 mg / m3n to about 20 mg / m3n, about 5 mg / m3n to about 15 mg / m3n, or about 5 mg / m3n to about 10 mg / m3n. In yet another embodiment, the odorant is present in the odorized fluid at a concentration of about 2 mg / m3n to about 20 mg / m3n, about 2 mg / m3n to about 15 mg / m3n, about 5 mg / m3n to about 20 mg / m3n, about 5 mg / m3n to about 15 mg / m3n, or about 5 mg / m3n to about 10 mg / m3n. As used herein, the units “mg / m3n” indicate a concentration (“mg / m3”) at normal (“n”) atmospheric pressure at a location, which, at sea level, is typically 1 bar or 14.7 psi.

[0113] An odorized fluid can be an odorized fluid that is suitable for a particular use, depending on the character of a fluid that is present in an odorized fluid. For example, an odorized fluid can be a fuel for a fuel cell, as described herein.

[0114] METHODS OF ODORIZING FLUIDS

[0115] Also provided herein are methods of odorizing fluids. In some embodiments, the methods include providing a fluid and contacting the fluid and an odorant or an odorant composition as provided herein to form an odorized fluid.

[0116] Before, during, or after any one or more of the limitations of the methods provided herein is / are performed, the fluid and / or the odorized fluid can be present in a fuel distribution system. The fuel distribution system can include any fuel supply infrastructure (fuel storage, fuel distribution, fuel delivery, etc.). In some embodiments, the methods of odorizing a fluid also include disposing the fluid and / or the odorized fluid in a fuel distribution system, such as any fuel supply infrastructure (fuel storage, fuel distribution, fuel delivery, etc.).

[0117] The providing of a fluid can include capturing the fluid. The fluid can be captured using any technique known in the art. In some embodiments, the methods also include pressurizing the odorized fluid, storing the odorized fluid, or a combination thereof. The odorant or the odorant composition can be in any phase, such as a liquid phase, a gaseous phase, or acombination thereof before, during, and / or after the contacting of the fluid and the odorant. The providing of the fluid can include providing a container in which the fluid is disposed, and the contacting of the fluid and the odorant or the odorant composition can include disposing the odorant or the odorant composition in the container. The providing of the fluid can include providing a first stream that includes the fluid. When a first stream that includes the fluid is provided, the contacting of the fluid and the odorant or the odorant composition can include contacting the first stream and a second stream that includes the odorant or the odorant composition.

[0118] The contacting of the fluid and the odorant or the odorant composition can be achieved using any known technique. For example, the contacting of the fluid and the odorant or odorant composition can include dispensing the odorant or the odorant composition with a liquid meter. As a further example, the contacting of the fluid and the odorant or the odorant composition can include nebulizing the odorant or the odorant composition.

[0119] FLUIDS

[0120] The odorants or odorant compositions provided herein can be used to odorize any fluid, and the odorized fluids can include any fluid. The fluids generally can be in any phase, e.g., liquid or gas. In some embodiments, the fluid includes a fuel gas. The fluid can include hydrogen gas (H2) or a hydrogen gas blend. The fluid can include a natural or synthetic combustion gas. The fluid can include natural gas, LNG (liquid natural gas), liquefied petroleum gas (LPG), municipal gas, heating gas, or a combination thereof. The fluid can include methane, ethane, ethene, acetylene, propane, propene, butane, isobutane, butene, pentane, or a combination thereof. The fluid can include water gas, synthesis gas, reform gas, generator gas, coke gas, or a combination thereof. The fluid can include a non-combustible gas. The fluid can include carbon monoxide, carbon dioxide, industrial gases (e.g., nitrogen (N2), oxygen (O2), argon, helium, etc.), or a combination thereof. In a particular embodiment, the fluid comprises hydrogen gas (H2) and at least 10 mol%, and more often, at least 20 mol%, at least 30 mol%, at least 50 mol%, at least 75 mol%, at least 85 mol%, at least 90 mol%, at least 95 mol%, at least 97 mol%, at least 98 mol%, or at least 99 mol% of the fluid is the hydrogen gas. In another embodiment, the fluid comprises hydrogen gas (H2) and from 10 mol% to 40 mol%, from 10 mol% to 30 mol%, from 10 mol% to 25 mol%, from 15 mol% to 30 mol%, or from 15 mol% to 25 mol% of the fluid is the hydrogen gas.

[0121] SENSORS

[0122] The compounds, such as terminal alkynes or terminal alkenes, or compositions provided herein can be used in combination with a sensor, such as a sensor designed to indicate the presence of a compound that is an odorant. Therefore, systems are provided herein that include a sensor and a compound, such as a terminal alkyne or terminal alkene, that is an odorant, or a sensor and a composition that includes a compound, such as a terminal alkyne or terminal alkene, that is an odorant.

[0123] A sensor can be coupled to any device or apparatus, such as a pipeline, a fuel supply, a fuel cell, or some other component of the fuel cell system, or any appliance using hydrogen as fuel, or any component of an appliance using hydrogen as fuel. The sensor can be located in proximity to a self-contained fuel supply, a fuel consumption unit, or both, which can permit the sensor to detect any leaks quickly and / or effectively. A sensor also can include circuitry programmed to shut down a fuel cell, other appliance or system, or any other components in the event of a detected leak. The addition of the sensor can facilitate use of organic odorants at very low concentrations that are not detectable by humans for special applications or circumstances. Furthermore, the odorant can be selected so that extremely high sensitivity and selectivity of the sensor can be realized to avoid false alarms.

[0124] METHODS OF GENERATING ENERGY

[0125] Also provided herein are methods of generating energy. The methods generally can include using any of the odorized fluids provided herein as a source of energy. The odorized fluids can be a fuel for an appliance or device, such as a fuel cell. In some embodiments, the methods include providing a fuel cell having an anode and contacting the anode and any of the odorized fluids provided herein, such as odorized hydrogen gas. The contacting of an anode and an odorized fluid can produce an oxidized odorized fluid.

[0126] In some embodiments, the methods include removing (e.g., scrubbing, adsorbing, absorbing, or decomposing) an odorant from the odorized fluid or the oxidized odorized fluid. The removal of the odorant can occur at any one or more points of the methods provided herein. For example, the methods can include removing an odorant from an oxidized odorized fluid or removing an odorant from an odorized fluid prior to contacting an anode and the odorized fluid. Removal of an odorant from a fuel gas can be necessary or desirable, in some instances, such as (i) when an odorant is detrimental for the end-use of a fuel gas or fuel gas consuming applianceand / or device, and / or (ii) when an odorant is not eliminated during the consumption of the fuel gas, which can result in an environmental release of the odorant, thereby possibly negating the ability of the odorant to indicate leaks.

[0127] In some embodiments, the methods include removing (e.g., scrubbing, adsorbing, absorbing, or decomposing) an odorant from an exit, off-gas, or flue gas from a fuel cell or any appliance using hydrogen. The odorants provided herein can be removed by any known technique, such as (i) specially designed or commercially available adsorption and / or absorption processes, (ii) a water trap, and / or (iii) a humidifier system based on an odorant’s solubility in water.

[0128] The removal (e.g., scrubbing, adsorbing, absorbing or decomposing) of a compound, such as a terminal alkyne, terminal alkene, additive, etc., from a treated fluid and / or an oxidized treated fluid can be achieved by any known technique. These techniques can include, but are not limited to, catalytic decomposition on metal, metal oxide, zeolite, or other substrates (see US7780933B2, US8658321B2, JP2018153634A, JP06317909B2, JP05766744B2, JP6306377A, JP04745557B2, US8444945B2, JP04822692B2, US7837964B2, US20080090115A1, US10889597 B2); absorption or adsorption on activated carbon, zeolites, silica, or other substrates (see JP07271867B2, JP05949333B2, JP2012143747A, JP2011201975A, JP05295689B2, JP2001019984A, JP2001157709A, US6875410B2, JP05051864B2, US805777B2, EP2337621B1); condensation; concentration; evaporation; filtration; membrane separation; or a combination thereof. In some embodiments, the removal of an odorant can include contacting an odorized fluid or an exhaust gas and an adsorption and / or absorption media, or membrane separation media.

[0129] More specifically, a compound can be removed from a fluid, such as a treated fluid or an oxidized treated fluid, by an adsorption or absorption media using one or more materials, such as a porous carrier. Non-limiting examples of such materials include silica- alumina; silica; alumina; zeolite, preferably a zeolite containing Ag, Cu, Zn, Ni, Fe, Ce, La, Zr, and Ti metallic element(s), titania, zirconia, magnesia, silica-magnesia, or zinc oxide; a porous inorganic oxide, such as one selected from the group consisting of Ag, Cu, Ni, Zn, Mn, Fe, Co, Al, Si, Ce, an alkali metal, an alkaline earth metal, or a rare earth metal; terra alba; clay; diatomaceous earth; activated carbon; activated carbon oxide; activated carbon formed byactivated carbon processing with nitric acid; an organometallic framework compound (MOF); and a polymer type-absorbent in granular form, powder form, and fibrous form.

[0130] A compound can be removed from a treated fluid by catalytic conversion to one or more compounds having a lower odor detection threshold using one or more materials, such as porous inorganic oxide selected from the group consisting of Ag, Cu, Ni, Zn, Mn, Fe, Co, Al, Si, B, P; an alkali metal; an alkaline earth metal (for example, oxides of magnesium, calcium, strontium and barium); a rare earth metal (for example, oxides of scandium, yttrium, cerium, ytterbium and lanthanum); and a transition metal (for example, oxides of nickel, cobalt, vanadium, chromium, manganese, molybdenum, tungsten, copper, silver, zinc, iron, titanium, and zirconium). Alternatively, the porous inorganic oxide can be selected from the group consisting of alumina, silica, silica-alumina, and cerium oxide; a transition metal oxide; a transition metal compound; an alkaline earth metal oxide; and a rare earth metal oxide.Preferably the transition metal is nickel, cobalt, vanadium, chromium, manganese, molybdenum, tungsten, copper, silver, zinc, iron, titanium, and zirconium. Preferably the alkaline earth metal is magnesium, calcium, barium, or strontium. Preferably the rare earth metal of the rare earth oxide is selected from scandium, yttrium, cerium, ytterbium, and lanthanum. Alternatively, a porous inorganic oxide can be selected from a group 13-14 oxide where the group 13-14 element is selected from boron, aluminum, gallium, silicon, germanium, and tin. Alternatively, a compound can be removed from a treated fluid using a precious metal catalyst such as Pt / Pd / Rh catalyst, Pt / Pd catalyst, Pt / Rh catalyst, Pd / Rh catalyst, Pt catalyst, Pd catalyst, Au catalyst, and Pt / AhCh catalyst; an oxide catalyst such a zeolite, silica-alumina, silica, alumina, zeolite, titania, zirconia, magnesia, silica-magnesia, and zinc oxide; a Cu-ZSM-5 catalyst; an organometallic framework compound (MOF) catalyst; and a perovskite type-catalyst in a granular form, a powder form, or fibrous form.

[0131] Alternatively, a compound can be removed from a treated fluid by scrubbing in a water trap or solvent trap containing alkali metal hydroxides, alkali metal Ci to C4 alkyl acid, inorganic peroxide, organic peroxide, perchlorate, ionic or nonionic emulsifier, or a combination thereof.

[0132] The removal of at least a portion of the odorant from the odorized fluid or the exhaust gas can include subjecting the odorized fluid or the exhaust gas to condensation. Thecondensation can include cooling, pressurizing, or a combination thereof the odorized fluid or the exhaust gas to recover the at least a portion of the odorant as a liquid.

[0133] The removal of at least a portion of the odorant from an odorized fluid or an exhaust gas can include contacting the odorized fluid or the exhaust gas and a membrane or fdter, wherein the membrane or the filter is configured to retain the odorant or the non-odorant components of the odorized fluid or the exhaust gas. The membrane can include a polymer such as polyethylene, polypropylene, a polyamide, a polyimide, a cellulose acetate, a polysulphone, a polydimethylsiloxane, a fluoropolymer (such as polytetrafluoroethylene (PTFE)), polyvinylidene fluoride (PVDF), ethylene and chlorotrifluoroethylene copolymer (ECTFE), perfluoro sulfonic acid polymer, (such as Nafion and Aquivion), a nanoporous material, a silica mesoporous material, a zeolite, a metal-organic framework (MOF), a perovskite, a metal, or a combination thereof.

[0134] An odorant removal unit can be inserted prior to the storage unit or fuel delivery system to an appliance, such as a fuel cell, to consume the fuel gas. Alternatively, an odorant removal unit can be inserted after the storage unit or the appliance that consumes the fuel gas. After removal, the odorant should be below the critical concentration that negatively impacts the performance of the fuel cell (e.g., below the concentration that reduces efficiency). Other processes in which a treated fluid can require removal of an odorant include chemical processes (e.g., hydrogenation and reduction reactions, metal hydride synthesis); petrochemical processes (e.g. hydrocracking, reforming, desulfurization); steel or iron production (for example, using direct reduced iron (DR1)); glass production; semiconductor and electronic production processes (including cleaning, annealing, epitaxy, doping, ion implantation, passivation, chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), plasma etching, atomic layer etching (ALE), diborane and digermane stabilization, and generating EUV light sources); cement production or processing; and other emerging technologies. Odorant removal should also be sufficient to allow dilution of a treated fluid in ambient air without causing false detection or warning of a leak.

[0135] An odorant or odorant composition can be at least partially consumable by the fuel cell, thereby improving the performance of the fuel cell, increasing the energy produced by the fuel cell, or a combination thereof relative to a fuel cell operated with the fluid of the odorized fluid in the absence of the odorant or the odorant composition.EXAMPLES

[0136] The disclosure is further illustrated by the following examples, which are not to be construed in any way as imposing limitations to the scope of this technology. Various other aspects, embodiments, modifications, and equivalents thereof which, after reading the description herein, can suggest themselves to one of ordinary skill in the art without departing from the spirit of the present disclosure or the scope of the appended claims.

[0137] EXAMPLE 1

[0138] Dilutions of various odorants were prepared by mixing an organic compound in water to prepare a concentrated solution based on the water solubility of the organic compound. The concentrated solution was then dissolved in water to reach a desired concentration. The actual concentration in the vial headspace and concentration exposure to the panelist varied based on the vapor pressure of the compounds tested and the diffusion of the compounds in air.

[0139] The odorant solutions at various concentrations were evaluated by olfactory testing using a method similar those disclosed in literature (see Journal of Applied Toxicology, 3, 272-289, 1983; Perception & Psychophysics, 39, 281-286, 1986) and an olfactory panel of at least 8 panel members.

[0140] The odor characteristic of each odorant was ranked from 1 (extremely unpleasant) to 10 (extremely pleasant). Each participant also gave a description of the odorant. Participants were exposed to 10-fold changes in concentration to determine the odor detection threshold from 0.001 mg / L to 10 mg / L. The odor detection threshold represented the lowest concentration at which the panelists could detect the odorant. The odor characteristic score for each compound was calculated by averaging the score (1-10) reported by each of the panel members for each dilution, and the lowest of these scores for each compound (independent of dilution) is reported in the following table.

[0141] The data show that some compounds perform similarly to THT when used as odorants. In the case of Example 1.1 (hept-2-yne), Example 1.3 (oct-3-yne), Example 1.5 (hex- l-en-5-yne), Example 1.6 (hept-l-en-6-yne), Example 1.7 (hex-l-yne), Comparative Example 1.15 (hepta- 1,6-diyne), Comparative Example 1.16 (octa-1, 7-diyne), Comparative Example 1.19(3-(propan-2-yloxy)-prop-l -yne) and Example 1.28 (hex-2-yne), the compounds provide a comparable or stronger odor than THT at a similar concentration.** 1 (extremely unpleasant) and 10 (extremely pleasant).

[0142] EXAMPLE 2

[0143] Dilutions of various odorants were prepared by mixing 50-100 mg / m3n of each compound in pure hydrogen gas (class 5.0) in a gas cylinder at 100 bar. The hydrogen cylinders were prepared by a gravimetric method, as defined in ISO 6142.

[0144] Odorized hydrogen samples were blended with air at ratios from about 50: 1 to 2000: 1. Olfactory panel members were asked to give their impression of the smell character and indicate whether they found the odorant to be unpleasant (e.g., would the odor cause serious concerns if smelled in a real-world application). The odor threshold was determined by stepwise increases of the concentration. The concentration was doubled every step, starting from a dilution rate of 1:2000. In some cases, even at the highest dilution (lowest concentration tested), the odorant could still be detected. In other cases, even at the highest concentration tested, the odorant could not be detected. For odorants in which this occurred, the odor detection threshold and nominal odor concentration are reported as less than (<) or greater than (>) the known concentration.

[0145] The nominal concentration of the odor strength was established by comparing the odor strength of each compound to a set concentration of the odorant tetrahydrothiophene (THT). This permitted quantification of the concentration of the test compound that matched the odor strength of THT. The THT concentration was set at about 1% v / v of nominal concentration, thereby simulating a typical detection concentration at 20% of the lower explosive limit of hydrogen (LEL = 4% v / v in air; ca. 0.8% v / v in air) and natural gas (LEL = 5% v / v; ca. 1% v / v in air) using a typical gas odorization concentration (18 mg / m3n; 5.0 ppm mol) of THT.

[0146] It is preferred to use a lower concentration of odorant to achieve the same odor strength as THT, indicating that the odor intensity curve as defined in ISO / DTS 18222 has a steeper slope, and that a compound has a lower odor detection threshold compared to THT. Preferably, a lower concentration will achieve an alarming level of odor, but the concentration of the odorant should be sufficient to result in an odor similar to that of THT.

[0147] Results of Example 2 are provided in the following table. The data show that some compounds performed similarly to THT when used as odorants. In the case of Example 2.1 (hept-2-yne), Example 2.2 (hept-3-yne), Comparative Example 2.6 (pent- 1 -yne), Example 2.5 (hex- 1 -yne), Example 2.9 (hex-l-en-5-yne), Comparative Example 2.11 (hepta- 1,6-diyne) and Example 2.19 (hex-2-yne), the compounds provided a comparable or stronger odor thanTHT at a similar concentration. In other Examples, including Example 2.1 (hept-2-yne) and Example 2.5 (hex-1 -yne), the compounds provided a comparable or stronger odor than THT at a lower concentration. In terms of selecting a suitable odorant, both of these are desirable traits.* As determined by the panel members.** Concentration required to match odor strength of THT at 1% v / vADilution equipment reached operational limit

[0148] The data of Examples 1 and 2 demonstrate that the l- / 2-hexynes, the 2- / 3- heptynes, and the 3- / 4-octynes are suitable gas odorants. The odor properties and alarmingcharacter of the 1 - / 2-hexynes, the 2- / 3 -heptynes, and the 3- / 4-octynes are comparable to a typical commercial natural gas odorant, namely tetrahydrothiophene (THT), and other alkynes considered to be suitable gas odorants, for instance, 1 -pentyne.

[0149] The data reveal several surprising and unexpected results. First, 1 - / 2-hexynes, 2- / 3 -heptynes, and 3- / 4-octynes have odor detection thresholds comparable to or lower than previously considered alkynes (e.g.,1 -pentyne) and can serve as a fluid (gas) odorant in hydrogen gas and other fluids despite having a higher number of total aliphatic carbons (which corresponds to a higher boiling point and lower vapor pressure). Second, 1 - / 2-hexynes, 2- / 3 -heptynes, and 3- / 4-octynes have an odor strength equal to or better than other alkynes (e.g., pent-l-yne) and THT. Third, 2- / 3-heptynes and 3- / 4-octynes have significantly lower odor detection thresholds compared to similar shorter alkynes despite having only two carbons as a flexible spacer (e.g., m=l in formula i). Fourth, 2- / 3-heptynes and 3- / 4-octynes demonstrate a distinct and unique odor compared to equivalent terminal alkynes (namely, hept-l-yne and oct-l-yne). These odor characteristics impart an alarming and unique smell similar to typical commercial natural gas odorants. Hept-2-yne demonstrates characteristic and unique smell properties compared to hex- 1-yne even though both are composed of four carbons as a flexible spacer (e.g., m=3 in formula i).

[0150] The data shown in Examples 1 and 2 also demonstrate that enyne compounds are suitable odorants for fluids, particularly gases. The odor properties and alarming odor character of enyne compounds are comparable to a typical commercial natural gas odorant (THT) and other alkynes considered to be gas odorants such as pent-l-yne. Surprisingly and unexpectedly, the enyne compounds do not behave like an alkyne or an alkene but instead have their own unique set of odor properties. Embodiments of the enyne compounds have odor detection levels equal to or lower than previously considered alkynes (pent-l-yne); odor strengths equal to or better than previously considered alkynes (pent-l-yne) and a typical commercial natural gas odorant (THT); significantly lower odor detection thresholds compared to similar length dienes and alkynes (for example, 1-heptyne, 1-octyne and 1,5 -hexadiene); and significantly worse odor characteristics compared to similar alkenes, dienes, and alkynes (for example, 1 -hexene, 1- heptyne and 1,5-hexadiene). These are all desirable properties when selecting an odorant compound.

[0151] EXAMPLE S

[0152] Dilutions of various odorants were prepared by mixing an organic compound in hydrogen gas (hydrogen class 5.0) to reach a concentration of about 120 mg / m3n in a gas cylinder at 100 bar. The hydrogen cylinders were prepared by a gravimetric method as defined in ISO 6142.

[0153] The Proton-exchange Membrane Fuel Cell (PEMFC) system was manufactured by Proton Technologies in the Netherlands. The tests were performed using an 8 cm2cell from Proton Technologies. The membrane electrode assemblies (MEA) were Proton Technologies Ames MEAs composed of 0.075 mg Pt per cm2(HyPer Pt / C 40%wt) for the anode and 0.3 mg Pt per cm2(HyPer Pt / C 40%wt) for the cathode on a Nafion 211 support.

[0154] The following parameters were used to perform the PEMFC tests:

[0155] Prior to testing the odorant, the PEMFC cell was purged with pure hydrogen. The T=0 value was defined as the time when the odorized hydrogen was injected into the PEMFC and the PEMFC was put into operation. The change of potential (e.g. voltage) at a constant 1 A / cm2current output correlates with the impact of the odorant on the fuel-cell performance during exposure to the odorant. For each batch of MEAs, a reference load was measured using pure hydrogen (class 5.0) without odorant to determine the baseline performance of the MEAbatch and allow comparison of the degradation effect for each odorant. Results are shown in the table below.

[0156] The evolution of potential (V) over the duration of the durability test in a protonexchange membrane fuel cell (PEMFC) system under a 1 A / cm2current load are shown in FIG. 1 to FIG 10. As shown in the figures, PEMFC performance in Example 3.1 through Example 3.8 (i.e., FIG. 1 to FIG. 8) all follow a similar trend as the reference. The absolute difference in performance between the reference hydrogen and the odorized hydrogen can likely be attributed to variability in MEA fabrication.

[0157] As shown in FIG. 9, PEMFC performance with butyraldehyde (Comparative Example 3.9) shows a rapid decline in performance (as indicated by a 120 mV decrease in electrical potential) in the first 15-30 minutes, followed by a slower performance loss (100 mV decrease in electrical potential) over the remaining duration of the test period as compared to the reference test using pure hydrogen. As shown in FIG. 10, PEMFC performance with THT(Comparative Example 3.10) shows a rapid decline after 5 minutes of operation. The data clearly show that these compounds deactivate the PEMFC catalyst, which results in the decline in performance.

[0158] It can be concluded from the durability tests at high odorant concentrations in Example 3 that alkynes according to this disclosure are suitable odorants for stable PEMFC operation. The potential (voltage) is maintained or improved over 24 hours under a 1 A / cm2current load. Furthermore, the alkynes according to this disclosure have significantly better performance compared to known poisonous substances for PEMFCs, such as aldehydes (e.g. butyraldehyde) and sulfur containing compounds (e.g. THT), further demonstrating their viability as hydrogen odorant in fuel cell applications.

[0159] EXAMPLE 4

[0160] The performance of various antioxidants was tested in a 100 mL 316L stainless steel autoclave equipped with a single bottom impeller mixing at 500 rotations per minute. To the autoclave, 20 g of 2-hexyne or 1 -hexyne was added, followed by the corresponding amount of antioxidant to be tested (ppm by weight). The mixture was then placed under air at 500 psig for 24 hours at 50 °C. The product was tested before and after exposure to air by gas chromatography analysis to determine its purity. An Agilent 8890 system equipped with a J&W HP-5 column was used for the analysis.

[0161] In a 250 mL Erlenmeyer was added successively 50 mL of 2-propanol (CAS #67- 63-0, 99.999% purity), 1 mL of an aqueous potassium iodide solution (CAS #7681-11-0, 99% purity) at 16.67 wt%, and 1 mL of glacial acetic acid (CAS #64-19-7, >99% purity). The Erlenmeyer was equipped with a magnetic stir bar and stirred at 200 rpm. The alkyne to be tested was added at a mass from 0.05 to 1 gram depending on the peroxide concentration. The reaction mixture was brought to a boil for one minute where it developed a yellow color. If the reaction mixture stayed colorless then a larger amount of the alkyne to be tested was used. If the reaction mixture became orange, a smaller amount of the alkyne to be tested was used. After the reaction mixture was cooled to room temperature, an aqueous solution of sodium thiosulfate (CAS #7772-98-7, 99% purity) at 0.0 IN concentration was added to titrate the solution until complete disappearance of color was observed. The amount of aqueous solution of sodium thiosulfate used was recorded as “volume equivalent.” The amount of peroxide in the alkyne was calculatedusing the following equation: Peroxide concentration in ppmw = 8000 * ((volume equivalent^.01) / sample mass).

[0162] The following compounds were tested for their antioxidant propertiesThese compounds have the following physicochemical propertiesn d. = no data foundThe table below lists the olfactory properties of these compounds from various literature sourcesn.d. = no data found

[0163] The following table shows the GC purity before and after exposure to oxygen and the peroxide level post ageing as determined by titration using the procedure defined above for the alkyne samples with or without the compounds listed in the tables above. The delta between the initial and final purity by GC may be reflective of the efficiency and ability of the compounds to suppress oxidation and degradation. Alkynes tested (Comparative Example 4.1-4) without antioxidant show significant degradation over the duration of the test as demonstrated by the lower purity post ageing and the increase in peroxide content. Similarly, THT (Comparative Example 4.5), a commonly used gas odorant, also shows a purity loss over the duration of the test. This loss is indicative of the acceptable purity losses for the alkynes if used as gas odorant. For the purposes of this test, any added compounds resulting in a reduction of purity of less than 1% after the ageing and / or a peroxide level below 400 ppmw are considered effective.* Compound visually not fully dissolved at the end of the experiment

[0164] Based on the data above, acetic acid (Example 4.16-4.17), diisopropylcarbinol (Example 4.26-4.29), diisopropyl ketone (Example 4.30-4.32), DMSO (Example 4.38), amyl acetate (Example 4.40), methyl sorbate (Example 4.44), carbohydrazine (Example 4.45), methyl salicylate (Example 4.52), and benzyl alcohol (Example 4.53) are not considered effective stabilizers to protect alkynes again oxidation. The results obtained with carbohydrazine (Example 4.45) highlight the critical importance of antioxidant solubility in alkynes to avoid degradation by oxidation.

[0165] Surprisingly, amine-based compounds such as DABCO (Example 4.34), tri ethylamine (Example 4.35) and DEHA (Example 4.39) have similar or better antioxidant properties to diphenylamine (Example 4.22-4.25), a well-known antioxidant. Considering their respective physicochemical properties and reported toxicity, DEHA and tri ethylamine are preferred compared to diphenylamine. Nonetheless, the concentration of amine-based antioxidant should be limited to a maximum of ca. 0.05 ppm (by mol) in the hydrogen gas phase to avoid performance issues in fuel-cell operation according the ISO 14687:2019 specifications which limit the ammonia (NH3) concentration to 0.1 ppm (by mol). Assuming a concentration of5 ppm (by mol) alkynes desired for use as odorant, the alkyne odorant composition can contain a maximum of ca. 1000 ppmw amine-based antioxidant.

[0166] Surprisingly, amyl acetate (example 4.40) and methyl salicylate (Example 4.52) are not effective as stabilizers or antioxidants for alkynes despite being reported as additives in gas odorant formulation based on acrylates (W02006067111A1 and W02006067115A1).Similarly, methyl sorbate (example 4.44) is not an effective stabilizer or antioxidant for alkynes despite equivalent sodium, calcium and potassium sorbate and sorbic acid being used as food preservatives. The same conclusion applies for benzyl alcohol (Example 4.53). It is a known antioxidant used in food and cosmetic applications but is not an effective stabilizer or antioxidant for alkynes. These results highlight that careful selection of the antioxidant compound is required, and it is not obvious that previously reported stabilizers and antioxidants will be effective for alkynes.

[0167] Surprisingly, not all the phenolic derivatives performed equally. TBHQ (Example 4.36) and methyl salicylate (Example 4.52) show worse oxidant protection considering the decrease in purity and / or peroxide concentration compared to all other phenolic derivatives. These results highlight once again that careful selection of the antioxidant compound is required, and it is not obvious that previously reported stabilizers and antioxidants will be effective for alkynes.

[0168] Surprisingly, isopropanol (Examples 4.10-4.15 & 4.42-4.43) and acetone (Examples 4.17-4.22) are as effective as well-known antioxidants such as BHT and BHA particularly at concentrations above 10000 ppmw. These results are even more surprising when compared to the results obtained for diisopropylcarbinol (Examples 4.26-4.29) and diisopropyl ketone (Examples 4.30-4.32) which have similar chemical structures but do not perform as effectively as antioxidants.

[0169] Based on these results, triethylamine, DEHA, cresols, ethylphenols, 2-methoxy-4- methyl-phenol, and 2-methoxyphenol are desirable candidates considering their physicochemical properties, e.g., low melting point and / or boiling point and reasonable vapor pressure.Considering the toxicity and olfactory properties, triethylamine, DEHA, 2-ethylphenol, 3- ethylphenol, 2-methoxy-4-methyl-phenol, and 2-methoxyphenol are preferred antioxidants among those tested.

[0170] For compounds having a high melting point (greater than 50 °C) and boiling point (greater than 200 °C), BHA is preferred over BHT, TBHQ, resorcinol, diphenylamine, and DABCO based on the lack of color formation after the oxidant test, low peroxide content, low byproduct formation, lower toxicity, and predicted better compatibility with fuel -cell due to absence of nitrogen atoms. For high melting point (greater than 50 °C) and boiling point (greater than 200 °C) compounds, the maximum concentration in the odorant formulation should not exceed 1000 ppmw, and preferably be equal to or lower than 200 ppmw to comply with technical guidelines defined in ISO 13734 :2013 which require that the mass fraction of odorant residues after evaporation should be less than 0.2 wt%. Above 1000 ppmw, the odorant composition comprising the compound antioxidant may not be fully vaporized during the gas odorization process, leading to precipitation, deposition on the pipeline walls, and / or blockage or plugging of the odorant injection system.

[0171] EXAMPLE 5

[0172] Gaseous blends of 1 -hexyne and various antioxidants were prepared in multiple steps. First, the mass equivalent to 1000 + / - 150 ppmw of antioxidants was added to pure 1- hexyne to form solution A and allowed to fully dissolved. Secondly, 1 pL of the 1 -hexyne and antioxidant solution A was injected using a liquid syringe into a Tedlar® gas bag fdled with 5 dm3of pure hydrogen gas (class 5.0) to form gas mixture B. Thirdly, 0.4 dm3of the gas mixture B was injected using a gas syringe into a second Tedlar® gas bag filled with 4.6 dm3of pure hydrogen gas (class 5.0) to form gas mixture C. The resulting mixture C was analyzed by gas chromatography to confirm that the 1 -hexyne concentration was approximately 10 mg / Nm3. Due to its very low concentration in gas mixture C, the antioxidant concentration could not be accurately quantified by gas chromatography. For these tests, the antioxidant concentration in the gas mixture C should be considered equivalent to the weight ratio to its original concentration in solution A, corresponding to 0.0100 + / - 0.0015 mg / Nm3.

[0173] An olfactory panel composed of 5 panelists was used to determine the impact of the antioxidant on the olfactory properties of 1 -hexyne. The panelists were exposed to a reference gas mixture made of pure 1 -hexyne and a test gas mixture including a specific antioxidant and 1 -hexyne mixture undisclosed to the panelists via two separate smelling ports. During the test, the panelists could go back and forth between both ports to determine if theantioxidant containing samples had different olfactory properties as compared to the pure 1 - hexyne reference. The pure 1 -hexyne reference gas mixture was composed of a 10 mg / Nm31- hexyne gas mixture in hydrogen diluted with clean air to reach about 1% v / v of nominal concentration, or a concentration of 0.1 mg / Nm31 -hexyne, thereby simulating a typical detection concentration at 20% of the lower explosive limit of hydrogen (LEL = 4% v / v in air; ca. 0.8% v / v in air) and natural gas (LEL = 5% v / v; ca. 1% v / v in air). The test gas mixture was prepared by adjusting the dilution factor of each gas mixture C based on the nominal 1 -hexyne concentration as determined by gas chromatography analysis to achieve the same final concentration of 0.1 mg / m31-hexyne and ca. 0.0001 mg / Nm3antioxidant concentration in the gas phase.

[0174] Each olfactory panel member was asked to give their impression of the odor character and odor strength for a test gas mixture including an undisclosed antioxidant in comparison to the pure 1-hexyne reference. The panelists were asked to indicate whether they found the test gas sample to be unpleasant (e.g., would the odor cause serious concerns if smelled in a real-world application) and if the odor character and odor strength was equivalent to the pure 1-hexyne reference. If a panelist concluded that the test gas sample had equivalent odor character and strength equivalent to the pure 1-hexyne reference, the smell character of the 1- hexyne and antioxidant gas mixture C was considered equivalent to pure 1-hexyne. If a panelist concluded that the test gas sample had either different odor character (smell was different than the pure 1-hexyne reference sample), the odor character of the 1-hexyne and antioxidant gas mixture C was considered different as compared to pure 1-hexyne. If a panelist concluded that the test gas sample had different odor strength (higher or lower odor intensity), the antioxidant was considered to have synergistic effects (higher odor strength) or antagonistic effects (lower odor strength, odor masking) compared to pure 1-hexyne.

[0175] Results are provided in the following table. In this table, A, B, C, D and E denote the feedback for each of the five individual panelists. The data shows that some antioxidants had an impact on the 1-hexyne odor characteristic. In the case of Example 5.1 (3 -ethylphenol), Example 5.2 (p-cresol), Example 5.4 (2-ethylphenol), and Example 5.5 (DEHA) different olfactory characteristics were observed by some of the panelists. For the other examples, both the 1-hexyne and antioxidant blends and pure 1-hexyne had equivalent olfactive characteristics.

[0176] Surprisingly, in all examples, the presence of an antioxidant in 1 -hexyne did not impact the alarming nature of 1 -hexyne compared to the reference pure 1 -hexyne despite some panelists identifying olfactory differences. Certain panelists identified a difference in odor characteristics for Example 5.1 (3 -ethylphenol) and Example 5.4 (2-ethylphenol). This is very surprising for Example 5.4 (2-ethylphenol) considering that the antioxidant concentration (about 0.0001 mg / m3) is significantly lower compared to the odor detection threshold reported in the literature. For both compounds, the unpleasantness of the smell is preserved and therefore, one can conclude that the presence of either 2- or 3-ethylphenol is not detrimental to the performanceof 1 -hexyne as odorant. Their presence actually enhances the alarming and unpleasant olfactive properties based on the feedback from some of the panelists. Certain panelists also identified a difference in odor intensity for Example 5.1 (3 -ethylphenol), Example 5.2 (p-cresol), and Example 5.5 (DEHA). Since an equal amount of panelists reported either lower or high odor strength for Example 5.1 (3 -ethylphenol), and Example 5.5 (DEHA), both antioxidants can be considered as having no impact on 1 -hexyne olfactory properties. Surprisingly, data collected for Example 5.2 (p-cresol) suggest that p-cresol can enhance the odor strength of 1 -hexyne even if a difference in odor character was not identified by the panelists.

[0177] For some applications, it is beneficial that the effective concentration of the antioxidant in the odorant results in an effective concentration in air below the odor detection threshold to avoid odor masking or fading phenomena. For example, 10 mg / Nm3alkynes containing 1000 ppmw antioxidant would result, at a concentration in air of 20 % of the hydrogen LEL (i.e. 1% in air), in a concentration of 0.0001 mg / Nm3of antioxidant in air during a leak. To avoid odor masking or fading phenomena, the odor detection threshold of the antioxidant should be significantly greater than this value to avoid its presence being detected and impacting the smell properties of the odorant. Data for example 5.3 and 5.5 to 5.8 clearly highlight such behavior. In this regard, compounds such as 3 -ethylphenol (Example 5.1) are not desirable antioxidant candidates due to the very low odor detection threshold. The reported odor detection threshold in the literature is lower than 0.0001 mg / Nm3, and it is reasonable to expect that the odorant olfactive properties would be affected by such compounds as demonstrated in Example 5.1. Phenolic compounds such as BHT, BHA, 2-ethylphenol, 4-ethylphenol, m-cresol, 2-methoxy-4-methylphenol, methyl salicylate, and 2-methoxyphenol are preferred considering the odor detection threshold reported in the literature. Similarly, amine-based compounds such as DEHA and diphenylamine are ideal candidates considering the very high odor detection threshold reported in the literature, ensuring that the odorant olfactive properties are not impacted by the presence of the antioxidant at a concentration where the antioxidant is effective. In comparison, one could use a significantly higher concentration of acetone and IPA as antioxidant due to their much higher odor detection. One of reasonable skill in the art would expect that the olfactory properties of the odorant will not be impacted even if concentrations as high as 50,000 ppmw IPA or acetone are used as antioxidant.

[0178] For some applications, it is beneficial that the antioxidant enhances the alarming smell of the odorant. This is particularly true if the antioxidant has an unpleasant smell which can synergistically work with the antioxidant. In this regard, 3-ethylphenol (Example 5.1), p- cresol (Example 5.2), and 2-ethylphenol (Example 5.4) are ideal antioxidant candidates due to their very low odor detection threshold and highly unpleasant odor character profiles which positively impact the performance of the odorant. Similarly, despite having high odor detection thresholds, antioxidants such as DEHA, DABCO, triethylamine, 2-methoxyphenol and 4- ethylphenol enhance the alarming characteristics of the odorant due to their highly unpleasant odor character profiles.

[0179] CONSTRUCTIVE EXAMPLE 6

[0180] Based on the experimental data shown in EXAMPLE 4 and 5, the compounds listed in the below table are antioxidants that would be suitable to protect alkynes against oxidation when used as gas odorants. These compounds have the following properties:ASPECTS

[0181] The following is a listing of non-limiting aspects of the disclosure:

[0182] Aspect 1. An odorant for a fluid, such as a gas, the odorant comprising, consisting essentially of, or consisting of an alkene or a substituted derivative thereof, an alkyne, or a substituted derivative thereof.

[0183] Aspect 2. The odorant of Aspect 1, wherein the alkene is a terminal alkene, such as a terminal C3-C20 alkene, a terminal C3-C19 alkene, a terminal C3-C18 alkene, a terminal C3-C17 alkene, a terminal C3-C16 alkene, a terminal C3-C15 alkene, a terminal C3-C14 alkene, a terminal C3-C13 alkene, a terminal C3-C12 alkene, a terminal C3-C11 alkene, a terminal C3-C10 alkene, a terminal C3-C9 alkene, a terminal C3-C8 alkene, or a terminal C3-C7 alkene.

[0184] Aspect 3. The odorant of any of the preceding Aspects, wherein the alkene is a diene, such as a butadiene, hexadiene, heptadiene or octadiene.

[0185] Aspect 4. The odorant of any of the preceding Aspects, wherein the alkyne is a terminal alkyne, such as a terminal C3-C20 alkyne, a terminal C3-C19 alkyne, a terminal C3-C18 alkyne, a terminal C3-C17 alkyne, a terminal C3-C16 alkyne, a terminal C3-C15 alkyne, a terminal C3-C14 alkyne, a terminal C3-C13 alkyne, a terminal C3-C12 alkyne, a terminal C3-C11 alkyne, a terminal C3-C10 alkyne, a terminal C3-C9 alkyne, a terminal C3-C8 alkyne, or a terminal C3-C7 alkyne.

[0186] Aspect 5. The odorant of any of the preceding Aspects, wherein the alkyne is a diyne, such as a heptadiyne or octadiyne.

[0187] Aspect 6. The odorant of any of the preceding Aspects, wherein the odorant is an enyne, such as a heptenyne or octenyne.

[0188] Aspect 7. The odorant of any of the preceding Aspects, wherein the alkyne is a heptyne or a substituted derivative thereof, an octyne or a substituted derivative thereof, or a combination thereof.

[0189] Aspect 8. The odorant of any of the preceding Aspects, wherein the odorant is non-toxic (e.g., to humans and / or other animals).

[0190] Aspect 9. The odorant of any of the preceding Aspects, wherein the odorant has a detectable odor below a toxicity level (e.g., for humans and / or other animals).

[0191] Aspect 10. The odorant of any of the preceding Aspects, wherein the odorant is environmentally benign, such as by not posing health, toxicity, or ecological concern to humans or other animals.

[0192] Aspect 11. The odorant of any of the preceding Aspects, wherein the odorant, upon combustion, is environmentally benign as a combustion product, such as by not posing health, toxicity, or ecological concern to humans or other animals.

[0193] Aspect 12. The odorant of any of the preceding Aspects, wherein the odorant does not undesirably impact the components of a device system, such as a combustion system, fuel cell, or any other appliance (for example, the odorant does not impact, or impacts by less than 1%, or less than 0.1 %, the performance (e.g., energy output) of a device).

[0194] Aspect 13. The odorant of any of the preceding Aspects, wherein the heptyne comprises, consists essentially of, or consists of a 2-heptyne.

[0195] Aspect 14. The odorant of any of the preceding Aspects, wherein the heptyne comprises, consists essentially of, or consists of a 3-heptyne.

[0196] Aspect 15. The odorant of any of the preceding Aspects, wherein the octyne comprises, consists essentially of, or consists of a 3-octyne.

[0197] Aspect 16. The odorant of any of the preceding Aspects, wherein the octyne comprises, consists essentially of, or consists of a 4-octyne.

[0198] Aspect 17. The odorant of any of the preceding Aspects, wherein the hexadiene, heptadiene, and / or octadiene includes a compound of formula (A):CH2=CH(CH2)mCH=CH2formula (A); wherein m is 2, 3 or 4 (e.g., m is 2 for a hexadiene and 4 for an octadiene).

[0199] Aspect 18. The odorant of any of the preceding Aspects, wherein the hexadiene heptadiene, and / or octadiene includes a compound of formula (B):CH3CH=CH(CH2)mCH=CH2formula (B); wherein m is 1, 2 or 3 (e.g., m is 1 for a hexadiene and 3 for an octadiene).

[0200] Aspect 19. The odorant of any of the preceding Aspects, wherein the hexadiene, heptadiene and / or octadiene includes a compound of formula (C):CH3(CH2)mCH=CH(CH2)nCH=CH3formula (C); wherein m is 0, 1, 2, or 3, and n is 0, 1, 2, or 3, wherein m + n = 1 for hexadienes, and m + n = 3 for octadienes.

[0201] Aspect 20. The odorant of any of the preceding Aspects, wherein the heptyne and / or the octyne comprises, consists essentially of, or consists of a compound of formula (IX):CH3-(CH2)m-C=C-(CH2)n-CH3 formula (IX); wherein m is 2 or 3; n is 0 or 1; and m + n = 3 or 4 (e.g., m + n = 3 for heptynes, and m + n = 4 for octynes).

[0202] Aspect 21. The odorant of any of the preceding Aspects, wherein the heptyne and / or the octyne comprises, consists essentially of, or consists of a compound of formula (X): (CH3)2CH-(CH2)m-C =C-(CH2),1-CH formula (X); wherein m is 1 or 2; n is 0 or 1; and m + n = 2 or 3 (e.g., m + n = 2 for heptynes, and m + n = 3 for octynes).

[0203] Aspect 22. The odorant of any of the preceding Aspects, wherein the heptyne and / or the octyne comprises, consists essentially of, or consists of a compound of formula (XI): (CH3)3C-(CH2)m-C=C-(CH2)n-CH3formula (XI); wherein m is 1 or 2; n is 0 or 1; and m + n = 2 or 3 (e.g., m + n = 2 for heptynes, and m + n = 3 for octynes).

[0204] Aspect 23. The odorant of any of the preceding Aspects, wherein the heptyne and / or the octyne comprises, consists essentially of, or consists of at least one of the following compounds:

[0205] Aspect 24. An odorant composition comprising, consisting essentially of, or consisting of the odorant of any of the preceding Aspects and an additive.

[0206] Aspect 25. The odorant composition of Aspect 24, wherein the additive is dispersed in the odorant, or the odorant is dispersed in the additive.

[0207] Aspect 26. The odorant composition of any of the preceding Aspects, wherein the additive is an odoriferous additive.

[0208] Aspect 27. The odorant composition of any of the preceding Aspects, wherein(A) the additive comprises, consists essentially of, or consists of methacrylic acid, an acrylic acid Ci-Ce alkyl ester, or a combination thereof; or (B) the additive does not include methacrylic acid, an acrylic acid Ci-Cs alkyl ester, or a combination thereof.

[0209] Aspect 28. The odorant composition of any of the preceding Aspects, wherein the additive includes a non-odiferous additive.

[0210] Aspect 29. The odorant composition of any of the preceding Aspects, wherein the additive is a stabilizer (i.e., a compound that prevents or delays the chemical degradation of an odorant).

[0211] Aspect 30. The odorant composition of any of the preceding Aspects, wherein the stabilizer comprises, consists essentially of, or consists of an antioxidant, a radical inhibitor, or a combination thereof.

[0212] Aspect 31. The odorant composition of any of the preceding Aspects, wherein the stabilizer comprises, consists essentially of, or consists of vitamin C or a derivative thereof (ascorbyl palmitate, ascorbyl acetate, etc.), a tocopherol or a derivative thereof (vitamin E, vitamin E acetate, etc.), vitamin A or a derivative thereof (vitamin A palmitate, etc.), a phenolic benzylamine, formic acid, acetic acid, benzoic acid, sorbic acid, butylated hydroxytoluene (tertbutyl hydroxytoluene (BHT)), butylated hydroxyanisole (BOA or BHA), 4-tert-butylcatechol (TBC), tert-butyl hydroxyanisole, 4-methoxyphenol (hydroquinone monomethyl ether (MeHQ)), 2-methoxyphenol (guaiacol), 2,6-di-tert-butyl phenol (2,6-DTBP), 2,5-di-tert-butyl-phenol (Ionol), benzene-l,2-diol (pyrocatechol), benzene- 1 ,4-diol (hydroquinone, HQ), benzene-l,3-diol (resorcinol), mono-tertiary-butylhydroquinone (MTBHQ), 2, 5-di-tertiary -butylhydroquinone (DTBHQ), tert-butyl hydroquinone (TBHQ), tolyhydroquinone (THQ), (2, 2,6,6- tetramethylpiperidin-l-yl)oxyl (TEMPO) and derivatives, N,N-dibenzylhydroxylamine (DBHA), hexamethylenetetramine (Methenamine or HMTA or HMT), para-benzoquinone (p-Bq), orthobenzoquinone (O-Bq), N-N, dimethylisopropanolamine (DMPA), phenothiazine (PTZ), 2,4- dinitrophenol (DNP), 2,4-dinitro-6-sec-butyl-phenol (DNBP), 2,6-dinitro-p-cresol, 1,4- phenylenediamine, N,N-dimethylaniline, melatonin, uric acid, glutathione or a combination thereof; alternatively, isopropanol (IP A), acetone, triethylamine, diethylhydroxylamine (DEHA), o-cresol, m-cresol, p-cresol, 2-ethylphenol, 3 -ethylphenol, 4-ethylphenol, 2-methoxy-4-methyl- phenol (creosol), 2-methoxyphenol, butylated hydroxyanisole (BHA), 2,6-bis(l, 1- dimethylethyl)-4-methylphenol (BHT), resorcinol, diphenylamine, l,4-diazabicyclo[2.2.2]octane (DABCO), or any combination thereof; alternatively, triethylamine, diethylhydroxylamine (DEHA), 2-ethylphenol, 3 -ethylphenol, 2-methoxy-4-methyl -phenol (creosol), 2-methoxyphenol, butylated hydroxyanisole (BHA), or any combination thereof; or alternatively, triethylamine, diethylhydroxylamine (DEHA), 2-ethylphenol, butylated hydroxy anisole (BHA), or any combination thereof.

[0213] Aspect 32. The odorant composition of any of the preceding Aspects, wherein the additive is a diluent for the odorant.

[0214] Aspect 33. The odorant composition of any of the preceding Aspects, wherein the additive comprises, consists essentially of, or consists of a Cs-Cs saturated hydrocarbon (a pentane, a cyclopentane, a hexane, a cyclohexane, a heptane, a cycloheptane, an octane, and / or a fluorinated hydrocarbon, such as, for example, PFC-116, PFC-c216, PFC218, or PFC-318).

[0215] Aspect 34. The odorant composition of any of the preceding Aspects, wherein the heptyne is present is present in the odorant composition at an amount of at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt%, based on the total weight of the odorant composition.

[0216] Aspect 35. The odorant composition of any of the preceding Aspects, wherein the octyne is present is present in the odorant composition at an amount of at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt%, based on the total weight of the odorant composition.

[0217] Aspect 36. The odorant composition of any of the preceding Aspects, wherein the heptyne and the octyne are present in the odorant composition at a total amount of at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt%, based on the total weight of the odorant composition (e.g., if 20 g of a heptyne and 30 g of an octyne are present in an odorant composition having a total weight of 100 g, then the heptyne and octyne are present in the odorant composition at a “total amount” of 50 wt%).

[0218] Aspect 37. An odorized fluid (or odorized fluid composition) comprising, consisting essentially of, or consisting of (i) a fluid, such as a gas, and (ii) the odorant of any of the preceding Aspects, or the odorant composition of any of the preceding Aspects, wherein the odorant or the odorant composition is dispersed in the fluid.

[0219] Aspect 38. The odorized fluid of Aspect 37, wherein the odorant or the odorant composition is evenly or unevenly dispersed in the fluid.

[0220] Aspect 39. The odorized fluid of any of the preceding Aspects, wherein the odorant is present in the odorized fluid at a concentration of 1,000 mg / m3n or less, 900 mg / m3nor less, 800 mg / m3n or less, 700 mg / m3n or less, 600 mg / m3n or less, 500 mg / m3n or less, 400 mg / m3n or less, 300 mg / m3n or less, 200 mg / m3n or less, 100 mg / m3n or less, 90 mg / m3n or less, 80 mg / m3n or less, 70 mg / m3n or less, 60 mg / m3n or less, 50 mg / m3n or less, 40 mg / m3n or less, 30 mg / m3n or less, 20 mg / m3n or less, or 10 mg / m3n or less.

[0221] Aspect 40. The odorized fluid of any of the preceding Aspects, wherein the odorant is present in the odorized fluid at a concentration of at least 0.5 mg / m3n, at least 1 mg / m3n, at least 2 mg / m3n, at least 3 mg / m3n, at least 4 mg / m3n, at least 5 mg / m3n, at least 6 mg / m3n, at least 7 mg / m3n, at least 8 mg / m3n, at least 9 mg / m3n, or at least 10 mg / m3n.

[0222] Aspect 41. The odorized fluid of any of the preceding Aspects, wherein the odorant is present in the odorized fluid at a concentration of about 1 mg / m3n to about 1,000 mg / m3n, about 1 mg / m3n to about 900 mg / m3n, about 1 mg / m3n to about 800 mg / m3n, about 1 mg / m3n to about 700 mg / m3n, about 1 mg / m3n to about 600 mg / m3n, about 1 mg / m3n to about 500 mg / m3n, about 1 mg / m3n to about 400 mg / m3n, about 1 mg / m3n to about 300 mg / m3n, about 1 mg / m3n to about 200 mg / m3n, about 1 mg / m3n to about 100 mg / m3n, about 1 mg / m3n to about 90 mg / m3n, about 1 mg / m3n to about 80 mg / m3n, about 1 mg / m3n to about 70 mg / m3n, about 1 mg / m3n to about 60 mg / m3n, about 1 mg / m3n to about 50 mg / m3n, about 1 mg / m3n to about 40 mg / m3n, about 1 mg / m3n to about 30 mg / m3n, about 1 mg / m3n to about 20 mg / m3n, or about 1 mg / m3n to about 10 mg / m3n.

[0223] Aspect 42. The odorized fluid of any of the preceding Aspects, wherein the odorant is present in the odorized fluid at a concentration of about 5 mg / m3n to about 5,000 mg / m3n, about 5 mg / m3n to about 2,500 mg / m3n, about 5 mg / m3n to about 1,000 mg / m3n, about 5 mg / m3n to about 900 mg / m3n, about 5 mg / m3n to about 800 mg / m3n, about 5 mg / m3n to about 700 mg / m3n, about 5 mg / m3n to about 600 mg / m3n, about 5 mg / m3n to about 500 mg / m3n, about 5 mg / m3n to about 400 mg / m3n, about 5 mg / m3n to about 300 mg / m3n, about 5 mg / m3n to about 200 mg / m3n, about 5 mg / m3n to about 100 mg / m3n, about 5 mg / m3n to about 90 mg / m3n, about 5 mg / m3n to about 80 mg / m3n, about 5 mg / m3n to about 70 mg / m3n, about 5 mg / m3n to about 60 mg / m3n, about 5 mg / m3n to about 50 mg / m3n, about 5 mg / m3n to about 40 mg / m3n, about 5 mg / m3n to about 30 mg / m3n, about 5 mg / m3n to about 20 mg / m3n, or about 5 mg / m3n to about 15 mg / m3n.

[0224] Aspect 43. The odorized fluid of any of the preceding Aspects, wherein the odorized fluid is a fuel for a fuel cell or other device or system.

[0225] Aspect 44. A method of odorizing a fluid, the method comprising, consisting essentially of, or consisting of providing a fluid, and contacting the (i) fluid, such as a gas, and (ii) the odorant of any of the preceding Aspects, or the odorant composition of any of the preceding Aspects to form an odorized fluid.

[0226] Aspect 45. The method or odorized fluid of any of the preceding Aspects, wherein the fluid and / or the odorized fluid is present in a fuel distribution system (such as any fuel supply infrastructure (fuel storage, fuel distribution, fuel delivery, etc.)).

[0227] Aspect 46. The method of any of the preceding Aspects, further comprising disposing the fluid and / or the odorized fluid in a fuel distribution system (such as any fuel supply infrastructure (fuel storage, fuel distribution, fuel delivery, etc.)).

[0228] Aspect 47. The method of any of the preceding Aspects, wherein the providing of the fluid comprises capturing the fluid.

[0229] Aspect 48. The method of any of the preceding Aspects, further comprising pressurizing the odorized fluid, storing the odorized fluid, or a combination thereof.

[0230] Aspect 49. The method of any of the preceding Aspects, wherein the odorant or the odorant composition is in a liquid phase, a gaseous phase, or a combination thereof before, during, and / or after the contacting of the fluid and the odorant.

[0231] Aspect 50. The method of any of the preceding Aspects, wherein the contacting of the fluid and the odorant, or the fluid and the odorant composition comprises dispensing the odorant or the odorant composition with a liquid meter.

[0232] Aspect 51. The method of any of the preceding Aspects, wherein the contacting of the fluid and the odorant or the odorant composition comprises nebulizing the odorant or the odorant composition.

[0233] Aspect 52. The method of any of the preceding Aspects, wherein the providing of the fluid comprises providing a container in which the fluid is disposed, and wherein the contacting of the fluid and the odorant or the odorant composition comprises disposing the odorant or the odorant composition in the container.

[0234] Aspect 53. The method of any of the preceding Aspects, wherein the providing of the fluid comprises providing a first stream comprising the fluid, and wherein the contacting of the fluid and the odorant or the odorant composition comprises contacting the first stream and a second stream comprising the odorant or the odorant composition.

[0235] Aspect 54. The odorant, odorant composition, odorized fluid, or method of any of the preceding Aspects, wherein the fluid is a gas (at atmospheric pressure and ambient temperature).

[0236] Aspect 55. The odorant, odorant composition, odorized fluid, or method of any of the preceding Aspects, wherein the fluid comprises, consists essentially of, or consists of a fuel gas.

[0237] Aspect 56. The odorant, odorant composition, odorized fluid, or method of any of the preceding Aspects, wherein the fluid comprises, consists essentially of, or consists of hydrogen gas (H2) or a hydrogen gas blend.

[0238] Aspect 57. The odorant, odorant composition, odorized fluid, or method of any of the preceding Aspects, wherein the fluid comprises, consists essentially of, or consists of a natural or synthetic combustion gas.

[0239] Aspect 58. The odorant, odorant composition, odorized fluid, or method of any of the preceding Aspects, wherein the fluid comprises, consists essentially of, or consists of natural gas, LNG (liquid natural gas), liquefied petroleum gas (LPG), municipal gas, heating gas, or a combination thereof.

[0240] Aspect 59. The odorant, odorant composition, odorized fluid, or method of any of the preceding Aspects, wherein the fluid comprises, consists essentially of, or consists of methane, ethane, ethene, acetylene, propane, propene, butane, isobutane, butene, pentane, or a combination thereof.

[0241] Aspect 60. The odorant, odorant composition, odorized fluid, or method of any of the preceding Aspects, wherein the fluid comprises consists essentially of, or consists of water gas, synthesis gas, reform gas, generator gas, coke gas, or a combination thereof.

[0242] Aspect 61. The odorant, odorant composition, odorized fluid, or method of any of the preceding Aspects, wherein the fluid comprises, consists essentially of, or consists of a noncombustible gas.

[0243] Aspect 62. The odorant, odorant composition, odorized fluid, or method of any of the preceding Aspects, wherein the fluid comprises, consists essentially of, or consists of carbon monoxide, carbon dioxide, an industrial gas (e.g., nitrogen (N2), oxygen (O2), argon, helium, etc.), or a combination thereof.

[0244] Aspect 63. A method of generating energy, the method comprising, consisting essentially of, or consisting of providing a fuel cell, the fuel cell comprises an anode; and contacting the anode and the odorized fluid of any of the preceding Aspects.

[0245] Aspect 64. The method of Aspect 63, wherein the contacting of the anode and the odorized fluid produces an oxidized odorized fluid.

[0246] Aspect 65. The method of any of the preceding Aspects, further comprising removing the odorant from the odorized fluid, wherein, optionally, the removing of the odorant is performed at least in part with any of the apparatuses or techniques provided herein, including, but not limited to, the use of catalytic decomposition, an adsorption media, an absorption media, a water trap, a solvent trap, etc.

[0247] Aspect 66. The method of any of the preceding Aspects, further comprising removing the odorant from the oxidized odorized fluid, wherein, optionally, the removing of the odorant is performed at least in part with any of the apparatuses or techniques provided herein, including, but not limited to, the use of catalytic decomposition, an adsorption media, an absorption media, a water trap, a solvent trap, etc.

[0248] Aspect 67. A method of removal, the method comprising providing the odorized fluid or the oxidized odorized fluid of any of the preceding Aspects; contacting the odorized fluid or the oxidized odorized fluid and a removal substrate or scrubber; wherein the removal substrate or scrubber reduces an amount of the odorant in the odorized fluid or the oxidized odorized fluid by adsorption, absorption, or chemical reaction by the use of catalytic decomposition, an adsorption or absorption media, a water trap, or a solvent trap to produce a deodorized fluid; wherein, optionally, the removal substrate or scrubber reduces the amount of the odorant in the odorized fluid or the oxidized odorized fluid by at least 80 %, at least 85 %, at least 90 %, at least 95 %, at least 99 %, at least 99.9 %, or 100 % (e.g., if the amount of odorant is reduced by 90 %, then a hypothetical starting odorant concentration of 10 units in an odorized fluid or oxidized odorized fluid would be reduced to 1 unit in the deodorized fluid).

[0249] Aspect 68. The method of any of the preceding Aspects, wherein the odorant or the odorant composition is at least partially consumable by the fuel cell, thereby optionally improving the performance of the fuel cell, increasing the energy produced by the fuel cell, or a combination thereof relative to a fuel cell operated with the fluid of the odorized fluid in the absence of the odorant or the odorant composition.

[0250] Aspect 69. The method of any of the preceding Aspects, wherein an amount of the odorant in the deodorized fluid is less than a critical concentration, wherein the critical concentration is a concentration of the odorant that, if exceeded, undesirably impacts the performance of an apparatus or a process in which the deodorized fluid is used, or to which the deodorized fluid is subjected.

[0251] Aspect 70. The method of any of the preceding Aspects wherein the deodorized fluid is used in and / or subjected to a fuel cell, a chemical process (e.g., hydrogenation and reduction reactions, metal hydride synthesis); petrochemical process (e.g. hydrocracking, reforming, desulfurization); steel production process (for example, using direct reduced iron (DRI)); glass production process; semiconductor and electronic production process (including cleaning, annealing, epitaxy, doping, ion implantation, passivation, chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), plasma etching, atomic layer etching (ALE), diborane and digermane stabilization, and generating EUV light sources); cement production process; a pharmaceutical production process, a food and beverage production process, a heat generation (e.g., combustion or catalytic) process, or a mechanical power generation (e.g., combustion) process and other emerging technologies or process requiring a deodorized fluid, or a combination thereof.

[0252] Aspect 71. A system comprising (i) a sensor, and (ii) the odorant or the odorant composition of any of the preceding Aspects.

[0253] Aspect 72. The system of Aspect 71, wherein the sensor is coupled to, or configured to be coupled to, a fuel supply, a fuel cell, another component of a fuel cell system, any appliance that uses hydrogen as fuel, or any component of an appliance that uses hydrogen as fuel.

[0254] Aspect 73. The system of any of the preceding Aspects, wherein the sensor comprises circuitry programmed to shut down a fuel cell, an appliance, or other system or component thereof in the event of a leak.

[0255] Aspect 74. The system of any of the preceding Aspects, wherein the sensor is configured to permit the use of any of the odorants of the preceding Aspects at a concentration that is not detectable by an average human.

Claims

CLAIMSWhat is claimed is:

1. An odorized fluid composition comprising:(i) a fluid;(ii) an alkyne odorant dispersed in the fluid; and(iii) an additive comprising a stabilizer, an antioxidant, and / or a radical inhibitor.

2. The composition of claim 1, wherein the fluid comprises a fuel gas.

3. The composition of claim 1, wherein the fluid comprises carbon dioxide, methane, propane, butane, or a combination thereof.

4. The composition of claim 1, wherein the fluid comprises hydrogen gas (H2) and at least 10 mol%, at least 20 mol%, at least 30 mol%, at least 50 mol%, at least 75 mol%, at least 85 mol%, at least 90 mol%, at least 95 mol%, at least 97 mol%, at least 98 mol%, or at least 99 mol% of the fluid is the hydrogen gas (H2); or from 10 mol% to 40 mol%, from 10 mol% to 30 mol%, from 10 mol% to 25 mol%, from 15 mol% to 30 mol%, or from 15 mol% to 25 mol% of the fluid is the hydrogen gas (H2).

5. The composition of any one of claims 1-4, wherein the alkyne odorant comprises at least 90 mol%, at least 95 mol%, at least 97 mol%, at least 98 mol%, or at least 99 mol% of a Ce-Cs alkyne.

6. The composition of any one of claims 1-5, wherein the alkyne odorant comprises hex-1- yne, hex-2-yne, hept-2-yne, or a combination thereof.

7. The composition of any one of claims 1-6, wherein the alkyne odorant comprises hex-1- yne.

8. The composition of any one of claims 1-7, wherein the alkyne odorant comprises hex-2- yne.

9. The composition of any one of claims 1-8, wherein the alkyne odorant comprises hept -2- yne.

10. The composition of any one of claims 1-9, wherein the alkyne odorant is present in the odorized fluid composition at a concentration of at least 0.5 mg / m3n, at least 1 mg / m3n, at least 2 mg / m3n, at least 3 mg / m3n, at least 4 mg / m3n, at least 5 mg / m3n, at least 6 mg / m3n, at least 7 mg / m3n, at least 8 mg / m3n, at least 9 mg / m3n, or at least 10 mg / m3n; and / or1,000 mg / m3n or less, 900 mg / m3n or less, 800 mg / m3n or less, 700 mg / m3n or less, 600 mg / m3n or less, 500 mg / m3n or less, 400 mg / m3n or less, 300 mg / m3n or less, 200 mg / m3n or less, 100 mg / m3n or less, 90 mg / m3n or less, 80 mg / m3n or less, 70 mg / m3n or less, 60 mg / m3n or less, 50 mg / m3n or less, 40 mg / m3n or less, 30 mg / m3n or less, 20 mg / m3n or less, or 10 mg / m3n or less.

11. The composition of any one of claims 1-10, wherein the alkyne odorant is present in the odorized fluid composition at a concentration of about 1 mg / m3n to about 50 mg / m3n, about 1 mg / m3n to about 40 mg / m3n, about 1 mg / m3n to about 30 mg / m3n, about 1 mg / m3n to about 20 mg / m3n, about 1 mg / m3n to about 10 mg / m3n, about 2 mg / m3n to about 50 mg / m3n, about 2 mg / m3n to about 40 mg / m3n, about 2 mg / m3n to about 30 mg / m3n, about 2 mg / m3n to about 20 mg / m3n, about 2 mg / m3n to about 15 mg / m3n, about 5 mg / m3n to about 50 mg / m3n, about 5 mg / m3n to about 40 mg / m3n, about 5 mg / m3n to about 30 mg / m3n, about 5 mg / m3n to about 20 mg / m3n, or about 5 mg / m3n to about 15 mg / m3n.

12. The composition of any one of claims 1-11, wherein the additive comprises a compound having a ketone moiety, a compound having an amine moiety, a compound having an alcohol moiety, a compound having a phenol moiety, or any combination thereof.

13. The composition of any one of claims 1-12, wherein the additive comprises isopropanol (IP A), acetone, triethylamine, diethylhydroxylamine (DEHA), o-cresol, m-cresol, p-cresol, 2- ethylphenol, 3 -ethylphenol, 4-ethylphenol, 2-methoxy-4-methyl -phenol (creosol), 2- methoxyphenol, butylated hydroxyanisole (BHA), 2,6-bis(l,l-dimethylethyl)-4-methylphenol (BHT), resorcinol, diphenylamine, l,4-diazabicyclo[2.2.2]octane (DABCO), 2-butylphenol, 3- m ethoxy 1 phenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2-(trifluoromethyl)phenol, 3- (trifluoromethyl)phenol, ethanolamine, dimethylaniline, diethylaniline or any combination thereof.

14. The composition of any one of claims 1-13, wherein the additive comprises: tri ethylamine, di ethylhydroxylamine (DEHA), 2-ethylphenol, 3 -ethylphenol, 2-methoxy- 4-methyl -phenol (creosol), 2-methoxyphenol, butylated hydroxyanisole (BHA), or any combination thereof; or triethylamine, diethylhydroxylamine (DEHA), 2-ethylphenol, butylated hydroxyanisole (BHA), or any combination thereof.

15. The composition of any one of claims 1-14, wherein the additive is present in the odorized fluid composition at a concentration of: about 10 ppmw to about 10 wt%, about 10 ppmw to about 8 wt%, about 10 ppmw to about 6 wt%, about 10 ppmw to about 4 wt%, about 10 ppmw to about 2 wt%, about 10 ppmw to about 1 wt%, about 10 ppmw to about 5,000 ppmw, about 50 ppmw to about 10 wt%, about 50 ppmw to about 8 wt%, about 50 ppmw to about 6 wt%, about 50 ppmw to about 4 wt%, about 50 ppmw to about 2 wt%, about 50 ppmw to about 1 wt%, about 50 ppmw to about 5,000 ppmw, about 50 ppmw to about 1,000 ppmw, about 200 ppmw to about 10 wt%, about 200 ppmw to about 8 wt%, about 200 ppmw to about 6 wt%, about 200 ppmw to about 4 wt%, about 200 ppmw to about 2 wt%, about 200 ppmw to about 1 wt%, about 200 ppmw to about 5,000 ppmw, or about 200 ppmw to about 2,000 ppmw, based on a weight of the alkyne odorant in the composition; or about 10 ppmw to about 1,000 ppmw, about 10 ppmw to about 900 ppmw, about 10 ppmw to 750 ppmw, about 10 ppmw to about 500 ppmw, about 50 ppmw to about 1,000 ppmw, about 50 ppmw to 750 ppmw, about 50 ppmw to about 500 ppmw, about 200 ppmw to about1,000 ppmw, about 200 ppmw to about 900 ppmw, about 200 ppmw to 750 ppmw, or about 200 ppmw to about 500 ppmw, based on the weight of the odorant in the composition.

16. The composition of any one of claims 1-15, wherein the odorized fluid composition is prepared by a process that comprises contacting the fluid, the alkyne odorant, and the additive in any order or sequence.

17. The composition of any one of claims 1-16, wherein the odorized fluid composition is prepared by a process that comprises: introducing the additive in solid form or liquid form through a first leak-tight inlet port into an odorant vessel; introducing the alkyne odorant through the first leak-tight inlet port or a second leak-tight inlet port into the odorant vessel and mixing with the additive to form an odorant composition; and discharging at least a portion of the odorant composition from the odorant vessel through a leak-tight outlet port and contacting with the fluid to form the odorized fluid composition.

18. The composition of any one of claims 1-16, wherein the odorized fluid composition is prepared by a process that comprises: introducing the additive in liquid form into a multiport vessel; connecting the multiport vessel to an odorant vessel containing the alkyne odorant and transferring the additive to the odorant vessel through a leak-tight inlet port and mixing the additive with the alkyne odorant to form an odorant composition; disconnecting the multiport vessel from the odorant vessel; and discharging at least a portion of the odorant composition from the odorant vessel through a leak-tight outlet port and contacting with the fluid to form the odorized fluid composition.

19. The composition of any one of claims 1-18, wherein the fluid or the odorized fluid composition is present in a fuel distribution system.

20. A method of generating energy, the method comprising:providing a fuel cell, wherein the fuel cell comprises an anode; and contacting the anode and the odorized fluid composition of any one of claims 1-19; wherein the contacting of the anode and the odorized fluid composition produces an oxidized odorized fluid.

21. The method of claim 20, further comprising removing the alkyne odorant from the odorized fluid composition or from the oxidized odorized fluid.

22. The method of claim 20 or 21, wherein the alkyne odorant is at least partially consumable by the fuel cell, thereby improving performance of the fuel cell, increasing energy produced by the fuel cell, or a combination thereof, relative to a fuel cell operated with the fluid of the odorized fluid composition in the absence of the alkyne odorant.

23. A method of removal, the method comprising: providing the odorized fluid composition of any one of claims 1-19; contacting the odorized fluid composition and a removal substrate or scrubber; wherein the removal substrate or scrubber reduces an amount of the alkyne odorant in the odorized fluid composition by adsorption, absorption, or chemical reaction by the use of catalytic decomposition, an adsorption or absorption media, a water trap, or a solvent trap to produce a deodorized fluid.

24. The method of claim 23, wherein the providing of the odorized fluid composition comprises contacting the odorized fluid composition and an anode to produce an oxidized odorized fluid prior to the contacting of the odorized fluid composition and the removal substrate or scrubber.

25. The method of claim 23 or 24, wherein the removal substrate or scrubber reduces the amount of the alkyne odorant in the odorized fluid composition by at least 90 %, at least 95 %, at least 99 %, or at least 99.9 %.

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