US8470933B2 - Coating for leak detection and method - Google Patents

Coating for leak detection and method Download PDF

Info

Publication number
US8470933B2
US8470933B2 US13/042,687 US201113042687A US8470933B2 US 8470933 B2 US8470933 B2 US 8470933B2 US 201113042687 A US201113042687 A US 201113042687A US 8470933 B2 US8470933 B2 US 8470933B2
Authority
US
United States
Prior art keywords
polymer
fluid
coating
odorant
polymer backbone
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active, expires
Application number
US13/042,687
Other versions
US20110165684A1 (en
Inventor
David L. Thorn
Karl K. Jonietz
James M. Boncella
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Triad National Security LLC
Original Assignee
Los Alamos National Security LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Los Alamos National Security LLC filed Critical Los Alamos National Security LLC
Priority to US13/042,687 priority Critical patent/US8470933B2/en
Publication of US20110165684A1 publication Critical patent/US20110165684A1/en
Application granted granted Critical
Publication of US8470933B2 publication Critical patent/US8470933B2/en
Assigned to TRIAD NATIONAL SECURITY, LLC reassignment TRIAD NATIONAL SECURITY, LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LOS ALAMOS NATIONAL SECURITY, LLC
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F136/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
    • C08F136/22—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having three or more carbon-to-carbon double bonds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F136/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
    • C08F136/02—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
    • C08F136/20—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds unconjugated
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
    • G01M3/12—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point by observing elastic covers or coatings, e.g. soapy water
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G01N31/22—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/689—Hydroentangled nonwoven fabric

Definitions

  • the present invention relates generally to leak detection and more particularly to chemical coatings that may be used for detecting and locating fluid leaks.
  • hydrogen gas will be a very widely used fuel, perhaps the fuel of choice for millions of fuel cells that could be used in vehicles, portable electronic devices, and small motorized devices (lawn mowers, snow blowers, and the like).
  • Hydrogen gas can leak through the tiniest imperfections in tanks, lines, or joints. Accumulated hydrogen is extremely flammable and, because it is odorless and colorless, hydrogen gas gives no warning of its presence.
  • Methanol is used in direct-methanol fuel cells and other devices. Methanol is toxic, and ingesting sub-lethal doses has caused blindness, so consumers generally are concerned about exposure to methanol.
  • fluids such as hydrogen and/or methanol
  • an aspect of the present invention includes a method for detecting a fluid leak.
  • the method involves applying to a surface a coating comprising a polymer that undergoes a chemical reaction with a fluid to produce a volatile odorant; allowing the coating to become exposed to fluid that chemically reacts with the polymer to generate the volatile odorant; and detecting the odorant.
  • Another aspect of the invention involves a coating that includes a polymer that chemically reacts with fluid to generate an odorant.
  • the present invention relates to leak detection and coatings used for detecting fluid leaks.
  • An aspect of the invention involves applying a coating on an exterior surface so that fluid from a leak can react with the coating to produce an odorant and/or a color change.
  • the coating could be applied on an exterior surface of a container that stores the fluid.
  • the coating could also be applied on fluid storage or transfer lines, room walls, floors, ceilings, valves, fittings, and on other surfaces such as the surface of a fuel cell. The coating would ordinarily go unnoticed. Leaked gas or liquid undergo a chemical reaction with the coating.
  • Some odorants useful with the invention have a strong and easily recognizable odor.
  • the coating may also undergo a change in appearance when exposed to small amounts of a confined fluid.
  • An aspect of this invention involves detecting and easily locating a hydrogen gas leak. Detecting such a leak would greatly reduce consumers' fears about the safety of using hydrogen as a fuel and could significantly reduce the risk of serious accidents.
  • a coating that could respond to methanol could alert consumers to small leaks of methanol and improve consumer confidence in using methanol for powering direct-methanol fuel cells in devices such as cellular telephones and laptop computers.
  • Coatings used with this invention are typically non-odorous when they are isolated from the fluid. However, when they come into contact with hydrogen, methanol, or other fluids, they react with the fluid and release the odorants that alert people in the vicinity of the leak and allow the people to respond before dangerous levels of the substance were released.
  • SCHEME 1 illustrates the preparation of an embodiment polymer by reacting commercially available MERRIFIELD RESIN (having polymer backbone (P) attached to chlorobenzyl groups) with a compound that is a precursor to the odorant “wine lactone”.
  • MERRIFIELD RESIN having polymer backbone (P) attached to chlorobenzyl groups
  • Wine lactone has a recognizable odor at a concentration of 10 ⁇ 14 gram per liter of air (see: Guth. Helv. Chim. Acta (1996) vol. 79, pp. 1559-1571, incorporated by reference).
  • SCHEME 1 also shows a chemical reaction that occurs when a coating including the polymer and a catalyst is exposed to a fluid leak of hydrogen gas (H 2 ).
  • MERRIFIELD RESIN reacts with precursor hydroxyl-acid compound to form the embodiment polymer, which includes benzyl ether groups.
  • the embodiment polymer is mixed with a catalyst such as palladium or a compound having palladium. This mixture is applied to a surface as a coating.
  • the coating is exposed to hydrogen from a leak, the polymer coating undergoes a hydrogenolysis reaction resulting in cleavage of a benzyl-oxygen bond and the release of the hydroxyl-acid, which is the odorant precursor that subsequently releases a molecule of water and is converted into the odorant.
  • Hydrogenolytic liberation of odorants from polymeric benzyl ethers is both general and flexible and it should be understood that the invention is not limited to the use of the specific precursor alcohol and odorant shown in SCHEME 1.
  • Many other odorant compounds can react with MERRIFIELD RESIN to produce a polymer that can undergo hydrogenolysis with hydrogen from a fluid leak to release odorant precursor, or odorant.
  • Hydroxylfuranones such as 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone (i.e. “maple lactone”), for example, react with MERRIFIELD RESIN to form embodiment polymers that release odorant hydroxylfuranones that are easily recognized and detected at concentrations below 1 part per billion (ppb) in air.
  • SCHEME 2 illustrates another embodiment of the invention.
  • a polymer releases an odorant amine.
  • the embodiment shown illustrates the release of odorant putrescine upon reaction with hydrogen.
  • the chemical reaction of MERRIFIELD RESIN with 1,4-diaminobutane or 1,5-diaminopentane produces an embodiment odorant-releasing polymer.
  • the odorant-releasing polymer is mixed with a catalyst (a finely divided catalyst having at least some palladium, for example).
  • the mixture is applied to a surface as a coating. When the coating is exposed to hydrogen, a chemical reaction occurs resulting in a hydrogenolysis reaction and the release of putrescine or cadaverine from the polymer.
  • SCHEME 3 illustrates another embodiment that is illustrative of the generation of odorants from polymers.
  • SCHEME 3 shows an embodiment odorant-releasing polymer having a MERRIFIELD RESIN backbone, a benzylic ether group, and a palladium(II) carboxylate group.
  • the synthesis of the odorant-releasing Pd-containing polymer is accomplished using standard techniques for the synthesis of Pd carboxylate complexes. Immobilization of this precursor on Merrifield resin is accomplished by deprotonation of the hydroxide group of the wine lactone precursor and addition is of the resultant anion to the Merrifield resin via nucleophilic attack on the chloromethyl group of the resin.
  • This polymer is mixed with a pH indicator, and the mixture is coated on a surface.
  • the Pd(II) carboxylate reacts with the H 2 .
  • the result is a reduction in oxidation state from Pd(II) to Pd(0) and the formation of acid.
  • the acid reacts with the pH indicator to produce a color change.
  • the Pd(0) that forms acts as a catalyst for subsequent hydrogenolysis of the benzylic ether to liberate hydroxy-acid, which loses a water molecule to form the “wine lactone”.
  • SCHEME 3 illustrates the following aspects of the invention: (i) using hydrogenolysis to liberate an odorant, (ii) using hydrogen to reduce Pd(II) to Pd(0) which becomes a catalyst for subsequent hydrogenolysis, (iii) using hydrogen to reduce Pd(II) as a means for locating a fluid leak, (iv) using hydrogen-produced Pd(0) as a catalyst to hydrogenolytically liberate an odorant, and (v) using the odorant for leak detection.
  • SCHEME 4 illustrates another embodiment concerned with producing odorants from polymers.
  • a polymer based on 1,4-benzenedimethanol, as illustrated in SCHEME 4, is mixed with a catalyst (such as palladium or a palladium compound).
  • a catalyst such as palladium or a palladium compound.
  • a membrane or coating of the mixture could be used as an indicator of a hydrogen leak. The membrane or coating would be weakened or ruptured by the presence of hydrogen. An odorant could be encapsulated within such a membrane. When the membrane ruptures, the odorant would be released.
  • SCHEME 5 shows an embodiment illustrating the use of hydrogen to activate a catalyst that ruptures a polymer and releases an odorant.
  • SCHEME 5 hydrogenolysis of a polymer detaches an olefin metathesis catalyst.
  • SCHEME 5 offers an amplification effect by allowing very small amounts of hydrogen to release relatively large amounts of odorant.
  • the R group is independently selected from aryl and alkyl having from 1-20 carbons (for example: phenyl, methylphenyl, ethylphenyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, etc.).
  • the polymer shown can be in the form a polymer membrane, and rupturing the polymer membrane would result in release of odorant.
  • SCHEME 5 illustrates a ruthenium (Ru) based metathesis catalyst in a side chain.
  • the catalyst is covalently attached to the polymer backbone via a benzylic-ether linkage.
  • the benzylic-ether linkage distances the metal center from the polymer backbone and prevents a chemical reaction between the metal is center and polymer backbone.
  • the polymer backbone includes olefins that can react with metal center.
  • the polymer reacts with hydrogen first to detach the side chain, which frees the catalyst from the polymeric backbone.
  • the now free catalyst can begin a metathesis reaction with the polymer that forms molecules of cyclopentene and cyclopentenol from the polymer backbone. These small molecules are odorants.
  • SCHEME 5 Some aspects of the invention illustrated by SCHEME 5 include (i) inactivation of a metathesis catalyst awaiting release when a specific substance (hydrogen, for example) is exposed to the polymer; (ii) a polymer and method wherein release of a metathesis catalyst from the polymer indicates detection of a specific substance (such as hydrogen); and (iii) using a metathesis catalyst to depolymerize a polymer to generate an odorant.
  • a specific substance such as hydrogen
  • a method for detecting a hydrogen gas leak involves preparing a mixture of an acid-sensitive pH indicator and a lightly colored salt (or salts) of Pd(II). When the mixture is coated on a surface and the coating is exposed to hydrogen gas, Pd(II) is reduced to Pd(0) and acid is produced that reacts with the pH indicator to produce a color change.
  • Representative Pd(II) salts include palladium chloride, palladium bromide, palladium iodide, and palladium sulfate.
  • a representative pH indicator is methyl red (2-[4-(dimethylamino)phenylazo]benzoic acid), which is yellow at a pH of about 6 and higher but becomes pink-red when it reacts with acid.
  • Other pH indicators could also be used for this purpose.
  • another method for detecting a hydrogen gas leak involves preparing a mixture of an oxidizing agent and a salt (or salts) of Pd(II).
  • Pd(II) salts include palladium chloride, palladium bromide, palladium iodide, and palladium sulfate.
  • a representative oxidizing agent is phosphomolybdic acid, which is ordinarily colorless or pale in color and becomes green, greenish-blue or blue when it reacts with a reducing agent.
  • Another representative oxidizing agent is the redox indicator tris(phenanthroline)iron(III), which is blue in color in the iron(III) oxidation state but becomes red when reduced. Other redox indicators could be employed for this purpose.
  • the coating and method can be used with hydrogen-powered vehicles and with smaller hydrogen-powered motorized units (e.g. lawn mowers, snow blowers), as a coating on hydrogen storage tanks and storage lines which would alert the operator if there were a hydrogen leak.
  • the invention can also be used by forming a coating on surfaces of, for example, the ceiling or walls of a enclosure (a garage, for example) so that if a hydrogen-powered vehicle or motorized unit leaked hydrogen while in the garage the coating would release odorant and/or be noticeably discolored.
  • the owner would detect the odorant or color change. Detection would alert the owner to a probable hazard before starting the vehicle or motorized unit.
  • the coating and method could also be used to coat the power-cell chamber of a portable electronic device, again to alert the operator if methanol or hydrogen were leaking from the device.
  • the coating and method would be useful in applications where methanol, hydrogen or other substances are produced and stored where it would be valuable to have the odor and visual indication of a leak.
  • the coating and method can be used to detect fluid leaks from a fuel cell.
  • Some advantages of the invention with regard to detection of a fuel leak from a fuel cell, compared to known leak detection methods involving odorants include the following: (i) the odorant is not present in the fluid itself, (ii) there are no issues with “poisoning” the components of a fuel cell from odorants present in the fluid, (iii) the natural exhaust of the fuel cell will be non-odorous.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Physics & Mathematics (AREA)
  • Organic Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Physics & Mathematics (AREA)
  • Medicinal Chemistry (AREA)
  • Biochemistry (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Biophysics (AREA)
  • General Health & Medical Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Molecular Biology (AREA)
  • Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)

Abstract

A coating is used to detect a fluid leak.

Description

RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 11/986,213 filed Nov. 19, 2007, hereby incorporated by reference.
STATEMENT REGARDING FEDERAL RIGHTS
This invention was made with government support under Contract No. DE-AC52-06NA25396 awarded by the U.S. Department of Energy awarded by the U.S. Department of Energy. The government has certain rights in the invention.
FIELD OF THE INVENTION
The present invention relates generally to leak detection and more particularly to chemical coatings that may be used for detecting and locating fluid leaks.
BACKGROUND OF THE INVENTION
In the emerging “hydrogen economy,” it is anticipated that hydrogen gas will be a very widely used fuel, perhaps the fuel of choice for millions of fuel cells that could be used in vehicles, portable electronic devices, and small motorized devices (lawn mowers, snow blowers, and the like). However, there remain safety concerns about using hydrogen as fuel for these purposes. Hydrogen gas can leak through the tiniest imperfections in tanks, lines, or joints. Accumulated hydrogen is extremely flammable and, because it is odorless and colorless, hydrogen gas gives no warning of its presence.
There has been considerable interest in developing chemical compounds that can be added to hydrogen that provide an easily detectable and recognizable odor so that anyone with a normal sense of smell could tell immediately if there were a hydrogen leak in the vicinity and take corrective action before an explosion or fire occurred. This approach has been used for many years to make natural gas and household gas immediately recognizable in the event of a gas leak or if a gas appliance (a gas furnace, gas stove, and the like) is releasing the gas, which has greatly contributed to the safe use and widespread acceptance of gas in households.
There are problems associated with adding odorants to hydrogen. Many odorizing compounds contain sulfur or nitrogen. These odorants cannot be used with devices such as fuel cells. Typical fuel cells have a platinum anode, and these types of odorants can “poison” the platinum anode or the electrolyte membrane and degrade the fuel cell's performance, even if present in very small amounts. For fuel cells that operate at lower temperatures, an odorant will not ordinarily be destroyed as it passes through the fuel cell into the exhaust, so some additional means must be taken to remove the odorant and prevent the normal exhaust from being mistaken for a hydrogen leak. In addition, hydrogen is so buoyant in air that leaking hydrogen and most of any odorant added to the hydrogen will float to accumulate in headspace. If this happens, there is risk that dangerous amounts of hydrogen will accumulate in the headspace before the odor of odorant additives can be noticed.
There are other fluids besides hydrogen that do not possess a distinctive odor or color and that are therefore difficult for people to detect directly, where the intended use of the substance does not easily admit adding an odorizing compound, and where a leak could be harmful or dangerous. One such substance is methanol. Methanol is used in direct-methanol fuel cells and other devices. Methanol is toxic, and ingesting sub-lethal doses has caused blindness, so consumers generally are concerned about exposure to methanol.
A material that could be applied to a surface of the container, to the container housing, to pipes, fittings, or other connections to the container, or to surfaces near the container as a coating that would respond to fluids such as hydrogen and/or methanol by chemically reacting with the fluid to produce a color change or release an detectable odorant could alert people to a leak yet not require anything being added directly to the fluid itself.
SUMMARY OF THE INVENTION
In accordance with the purposes of the present invention, as embodied and broadly described herein, an aspect of the present invention includes a method for detecting a fluid leak. The method involves applying to a surface a coating comprising a polymer that undergoes a chemical reaction with a fluid to produce a volatile odorant; allowing the coating to become exposed to fluid that chemically reacts with the polymer to generate the volatile odorant; and detecting the odorant.
Another aspect of the invention involves a coating that includes a polymer that chemically reacts with fluid to generate an odorant.
DETAILED DESCRIPTION
The present invention relates to leak detection and coatings used for detecting fluid leaks. An aspect of the invention involves applying a coating on an exterior surface so that fluid from a leak can react with the coating to produce an odorant and/or a color change. The coating could be applied on an exterior surface of a container that stores the fluid. The coating could also be applied on fluid storage or transfer lines, room walls, floors, ceilings, valves, fittings, and on other surfaces such as the surface of a fuel cell. The coating would ordinarily go unnoticed. Leaked gas or liquid undergo a chemical reaction with the coating. For example, if the coating was applied to a fluid container and there were a leak of a fluid such as hydrogen or methanol from the container, then an odorant would be released from the point of leakage. Depending on the coating, a change in appearance, such as a color change, could also be observable at the leaking point.
Some odorants useful with the invention have a strong and easily recognizable odor. The coating may also undergo a change in appearance when exposed to small amounts of a confined fluid.
An aspect of this invention involves detecting and easily locating a hydrogen gas leak. Detecting such a leak would greatly reduce consumers' fears about the safety of using hydrogen as a fuel and could significantly reduce the risk of serious accidents. A coating that could respond to methanol could alert consumers to small leaks of methanol and improve consumer confidence in using methanol for powering direct-methanol fuel cells in devices such as cellular telephones and laptop computers.
Coatings used with this invention are typically non-odorous when they are isolated from the fluid. However, when they come into contact with hydrogen, methanol, or other fluids, they react with the fluid and release the odorants that alert people in the vicinity of the leak and allow the people to respond before dangerous levels of the substance were released.
SCHEME 1 below illustrates the preparation of an embodiment polymer by reacting commercially available MERRIFIELD RESIN (having polymer backbone (P) attached to chlorobenzyl groups) with a compound that is a precursor to the odorant “wine lactone”. Wine lactone has a recognizable odor at a concentration of 10−14 gram per liter of air (see: Guth. Helv. Chim. Acta (1996) vol. 79, pp. 1559-1571, incorporated by reference). SCHEME 1 also shows a chemical reaction that occurs when a coating including the polymer and a catalyst is exposed to a fluid leak of hydrogen gas (H2).
Figure US08470933-20130625-C00001
As SCHEME 1 shows, MERRIFIELD RESIN reacts with precursor hydroxyl-acid compound to form the embodiment polymer, which includes benzyl ether groups. The embodiment polymer is mixed with a catalyst such as palladium or a compound having palladium. This mixture is applied to a surface as a coating. When the coating is exposed to hydrogen from a leak, the polymer coating undergoes a hydrogenolysis reaction resulting in cleavage of a benzyl-oxygen bond and the release of the hydroxyl-acid, which is the odorant precursor that subsequently releases a molecule of water and is converted into the odorant.
Hydrogenolytic liberation of odorants from polymeric benzyl ethers, such as the one shown in SCHEME 1, is both general and flexible and it should be understood that the invention is not limited to the use of the specific precursor alcohol and odorant shown in SCHEME 1. Many other odorant compounds can react with MERRIFIELD RESIN to produce a polymer that can undergo hydrogenolysis with hydrogen from a fluid leak to release odorant precursor, or odorant. Hydroxylfuranones such as 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone (i.e. “maple lactone”), for example, react with MERRIFIELD RESIN to form embodiment polymers that release odorant hydroxylfuranones that are easily recognized and detected at concentrations below 1 part per billion (ppb) in air.
SCHEME 2 illustrates another embodiment of the invention. In this embodiment, a polymer releases an odorant amine. The embodiment shown illustrates the release of odorant putrescine upon reaction with hydrogen.
Figure US08470933-20130625-C00002
The chemical reaction of MERRIFIELD RESIN with 1,4-diaminobutane or 1,5-diaminopentane (i.e. putrescine or cadaverine, respectively) produces an embodiment odorant-releasing polymer. The odorant-releasing polymer is mixed with a catalyst (a finely divided catalyst having at least some palladium, for example). The mixture is applied to a surface as a coating. When the coating is exposed to hydrogen, a chemical reaction occurs resulting in a hydrogenolysis reaction and the release of putrescine or cadaverine from the polymer.
SCHEME 3 illustrates another embodiment that is illustrative of the generation of odorants from polymers.
Figure US08470933-20130625-C00003
SCHEME 3 shows an embodiment odorant-releasing polymer having a MERRIFIELD RESIN backbone, a benzylic ether group, and a palladium(II) carboxylate group. The synthesis of the odorant-releasing Pd-containing polymer is accomplished using standard techniques for the synthesis of Pd carboxylate complexes. Immobilization of this precursor on Merrifield resin is accomplished by deprotonation of the hydroxide group of the wine lactone precursor and addition is of the resultant anion to the Merrifield resin via nucleophilic attack on the chloromethyl group of the resin. This polymer is mixed with a pH indicator, and the mixture is coated on a surface. When the coating is exposed to H2, the Pd(II) carboxylate reacts with the H2. The result is a reduction in oxidation state from Pd(II) to Pd(0) and the formation of acid. The acid reacts with the pH indicator to produce a color change. The Pd(0) that forms acts as a catalyst for subsequent hydrogenolysis of the benzylic ether to liberate hydroxy-acid, which loses a water molecule to form the “wine lactone”. SCHEME 3 illustrates the following aspects of the invention: (i) using hydrogenolysis to liberate an odorant, (ii) using hydrogen to reduce Pd(II) to Pd(0) which becomes a catalyst for subsequent hydrogenolysis, (iii) using hydrogen to reduce Pd(II) as a means for locating a fluid leak, (iv) using hydrogen-produced Pd(0) as a catalyst to hydrogenolytically liberate an odorant, and (v) using the odorant for leak detection.
SCHEME 4 illustrates another embodiment concerned with producing odorants from polymers.
Figure US08470933-20130625-C00004
A polymer based on 1,4-benzenedimethanol, as illustrated in SCHEME 4, is mixed with a catalyst (such as palladium or a palladium compound). A membrane or coating of the mixture could be used as an indicator of a hydrogen leak. The membrane or coating would be weakened or ruptured by the presence of hydrogen. An odorant could be encapsulated within such a membrane. When the membrane ruptures, the odorant would be released.
SCHEME 5 shows an embodiment illustrating the use of hydrogen to activate a catalyst that ruptures a polymer and releases an odorant.
Figure US08470933-20130625-C00005
In SCHEME 5, hydrogenolysis of a polymer detaches an olefin metathesis catalyst. SCHEME 5 offers an amplification effect by allowing very small amounts of hydrogen to release relatively large amounts of odorant. The R group is independently selected from aryl and alkyl having from 1-20 carbons (for example: phenyl, methylphenyl, ethylphenyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, etc.). The polymer shown can be in the form a polymer membrane, and rupturing the polymer membrane would result in release of odorant. SCHEME 5 illustrates a ruthenium (Ru) based metathesis catalyst in a side chain. Thus, the catalyst is covalently attached to the polymer backbone via a benzylic-ether linkage. The benzylic-ether linkage distances the metal center from the polymer backbone and prevents a chemical reaction between the metal is center and polymer backbone. The polymer backbone includes olefins that can react with metal center. As SCHEME 5 shows, the polymer reacts with hydrogen first to detach the side chain, which frees the catalyst from the polymeric backbone. The now free catalyst can begin a metathesis reaction with the polymer that forms molecules of cyclopentene and cyclopentenol from the polymer backbone. These small molecules are odorants. Some aspects of the invention illustrated by SCHEME 5 include (i) inactivation of a metathesis catalyst awaiting release when a specific substance (hydrogen, for example) is exposed to the polymer; (ii) a polymer and method wherein release of a metathesis catalyst from the polymer indicates detection of a specific substance (such as hydrogen); and (iii) using a metathesis catalyst to depolymerize a polymer to generate an odorant.
In another aspect of the invention, a method for detecting a hydrogen gas leak involves preparing a mixture of an acid-sensitive pH indicator and a lightly colored salt (or salts) of Pd(II). When the mixture is coated on a surface and the coating is exposed to hydrogen gas, Pd(II) is reduced to Pd(0) and acid is produced that reacts with the pH indicator to produce a color change. Representative Pd(II) salts include palladium chloride, palladium bromide, palladium iodide, and palladium sulfate. A representative pH indicator is methyl red (2-[4-(dimethylamino)phenylazo]benzoic acid), which is yellow at a pH of about 6 and higher but becomes pink-red when it reacts with acid. Other pH indicators could also be used for this purpose.
In yet another aspect of the invention, another method for detecting a hydrogen gas leak involves preparing a mixture of an oxidizing agent and a salt (or salts) of Pd(II). When the mixture is coated on a surface and the coating is exposed to hydrogen gas, Pd(II) is reduced to Pd(0), which reacts with the oxidizing agent to produce a color change. Representative Pd(II) salts include palladium chloride, palladium bromide, palladium iodide, and palladium sulfate. A representative oxidizing agent is phosphomolybdic acid, which is ordinarily colorless or pale in color and becomes green, greenish-blue or blue when it reacts with a reducing agent. Another representative oxidizing agent is the redox indicator tris(phenanthroline)iron(III), which is blue in color in the iron(III) oxidation state but becomes red when reduced. Other redox indicators could be employed for this purpose.
The coating and method can be used with hydrogen-powered vehicles and with smaller hydrogen-powered motorized units (e.g. lawn mowers, snow blowers), as a coating on hydrogen storage tanks and storage lines which would alert the operator if there were a hydrogen leak. The invention can also be used by forming a coating on surfaces of, for example, the ceiling or walls of a enclosure (a garage, for example) so that if a hydrogen-powered vehicle or motorized unit leaked hydrogen while in the garage the coating would release odorant and/or be noticeably discolored. The owner would detect the odorant or color change. Detection would alert the owner to a probable hazard before starting the vehicle or motorized unit. The coating and method could also be used to coat the power-cell chamber of a portable electronic device, again to alert the operator if methanol or hydrogen were leaking from the device. The coating and method would be useful in applications where methanol, hydrogen or other substances are produced and stored where it would be valuable to have the odor and visual indication of a leak.
The coating and method can be used to detect fluid leaks from a fuel cell. Some advantages of the invention with regard to detection of a fuel leak from a fuel cell, compared to known leak detection methods involving odorants include the following: (i) the odorant is not present in the fluid itself, (ii) there are no issues with “poisoning” the components of a fuel cell from odorants present in the fluid, (iii) the natural exhaust of the fuel cell will be non-odorous.
The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching.
The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.

Claims (12)

What is claimed is:
1. A method for detecting a fluid leak comprising:
applying to a surface a coating comprising a polymer and a catalyst that catalyzes a reaction with the polymer and fluid from the fluid leak to produce an odorant;
allowing the coating to become exposed to the fluid; and
detecting the odorant.
2. The method of claim 1, wherein the polymer and catalyst are chemically bonded to each other before allowing the coating to become exposed to the fluid.
3. The method of claim 1, wherein the fluid comprises hydrogen gas or methanol.
4. The method of claim 1, wherein the catalyst comprises palladium or a compound having palladium.
5. The method of claim 1, wherein the polymer comprises a polymer backbone and a side chain attached to the polymer backbone, wherein at least part of the side chain detaches from the polymer and the odorant forms from the detached portion of the side chain.
6. The method of claim 5, wherein the polymer is of the formula
Figure US08470933-20130625-C00006
wherein P is a polymer backbone and X is chosen from an isobutyrate group or a group of the formula
Figure US08470933-20130625-C00007
or —NH(CH2)4NH2 or —NH(CH2)5NH2.
7. The method of claim 1, wherein the polymer backbone P comprises a polymer backbone and a side chain attached to the polymer backbone, wherein the odorant forms from the polymer backbone.
8. The method of claim 7, wherein the polymer backbone comprises olefins, wherein the side chain reacts with fluid and thereafter detaches from the polymer and forms a catalyst that reacts with polymer backbone and fluid to depolymerize the polymer backbone and form odorant molecules or odorant molecule precursors from the polymer backbone.
9. The method of claim 8, wherein the polymer is of the formula
Figure US08470933-20130625-C00008
wherein n is an integer greater than 1 and R is selected independently from aryl and alkyl having 1 to 20 carbons.
10. The method of claim 1, wherein said coating further comprises a chemical that produces a detectable color change as a result of an acid-base reaction after the coating is exposed to the fluid.
11. The method of claim 10, wherein the chemical that produces a detectable color change comprises an acid-base indicator.
12. The method of claim 1, wherein said coating further comprises a chemical that produces a detectable color change as a result of a redox reaction after the coating is exposed to the fluid.
US13/042,687 2007-11-19 2011-03-08 Coating for leak detection and method Active 2028-09-14 US8470933B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US13/042,687 US8470933B2 (en) 2007-11-19 2011-03-08 Coating for leak detection and method

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US11/986,213 US7915047B2 (en) 2007-11-19 2007-11-19 Coating for leak detection and method
US13/042,687 US8470933B2 (en) 2007-11-19 2011-03-08 Coating for leak detection and method

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US11/986,213 Division US7915047B2 (en) 2007-11-19 2007-11-19 Coating for leak detection and method

Publications (2)

Publication Number Publication Date
US20110165684A1 US20110165684A1 (en) 2011-07-07
US8470933B2 true US8470933B2 (en) 2013-06-25

Family

ID=40642649

Family Applications (2)

Application Number Title Priority Date Filing Date
US11/986,213 Expired - Fee Related US7915047B2 (en) 2007-11-19 2007-11-19 Coating for leak detection and method
US13/042,687 Active 2028-09-14 US8470933B2 (en) 2007-11-19 2011-03-08 Coating for leak detection and method

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US11/986,213 Expired - Fee Related US7915047B2 (en) 2007-11-19 2007-11-19 Coating for leak detection and method

Country Status (2)

Country Link
US (2) US7915047B2 (en)
WO (1) WO2009067146A1 (en)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140251831A1 (en) * 2013-03-07 2014-09-11 Kenneth D. Ley LEAK DETECTION FORMULA, ANALYZER and METHODS OF USE
US11636870B2 (en) 2020-08-20 2023-04-25 Denso International America, Inc. Smoking cessation systems and methods
US11732652B2 (en) 2021-03-23 2023-08-22 General Electric Company Removing safety markers from a hydrogen fuel system
US11760169B2 (en) 2020-08-20 2023-09-19 Denso International America, Inc. Particulate control systems and methods for olfaction sensors
US11760170B2 (en) 2020-08-20 2023-09-19 Denso International America, Inc. Olfaction sensor preservation systems and methods
US11788474B2 (en) 2022-03-07 2023-10-17 General Electric Company Pericritical fluid systems for turbine engines
US11813926B2 (en) 2020-08-20 2023-11-14 Denso International America, Inc. Binding agent and olfaction sensor
US11828210B2 (en) 2020-08-20 2023-11-28 Denso International America, Inc. Diagnostic systems and methods of vehicles using olfaction
US11881093B2 (en) 2020-08-20 2024-01-23 Denso International America, Inc. Systems and methods for identifying smoking in vehicles
US11927142B2 (en) 2022-07-25 2024-03-12 General Electric Company Systems and methods for controlling fuel coke formation
US11932080B2 (en) 2020-08-20 2024-03-19 Denso International America, Inc. Diagnostic and recirculation control systems and methods
US11946378B2 (en) 2022-04-13 2024-04-02 General Electric Company Transient control of a thermal transport bus
US11953404B1 (en) * 2013-02-01 2024-04-09 Automotive Test Solutions, Inc. Composition of matter for identifying the location of a leak site
US12018594B2 (en) 2022-03-07 2024-06-25 General Electric Company Pericritical fluid systems for turbine engines
US12017506B2 (en) 2020-08-20 2024-06-25 Denso International America, Inc. Passenger cabin air control systems and methods
US12037128B2 (en) 2021-03-23 2024-07-16 General Electric Company Safety markers for a hydrogen fuel system
US12251991B2 (en) 2020-08-20 2025-03-18 Denso International America, Inc. Humidity control for olfaction sensors
US12253033B2 (en) 2022-10-04 2025-03-18 General Electric Company Hydrogen fuel leak detection system for a vehicle
US12264588B2 (en) 2022-03-07 2025-04-01 General Electric Company Liquid fluid systems including phase detection sensors for turbine engines
US12269315B2 (en) 2020-08-20 2025-04-08 Denso International America, Inc. Systems and methods for measuring and managing odor brought into rental vehicles

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011007259A1 (en) 2011-04-13 2012-10-18 Schaeffler Technologies AG & Co. KG Drive device with an electric machine
KR101926867B1 (en) * 2012-07-30 2018-12-07 현대자동차주식회사 Pin hole inspection apparatus for MEA of fuel cell
WO2018082785A1 (en) * 2016-11-07 2018-05-11 Abb Schweiz Ag An industrial robot for food industry comprising a leakage detection device
DE102017203607A1 (en) 2017-03-06 2018-09-06 Bayerische Motoren Werke Aktiengesellschaft Hydrogen-carrying component, fuel cell system and motor vehicle
EP4498057A1 (en) * 2023-07-27 2025-01-29 Airbus Operations GmbH Leakage detection

Citations (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2416061A (en) 1943-10-27 1947-02-18 Du Pont Curing of polymers of substituted monoolefinic hydrocarbons with polyvalent metal compounds
US4657700A (en) 1983-10-07 1987-04-14 Givaudan Corporation Fragrance compositions containing benzyl ethers
US4786425A (en) 1986-01-13 1988-11-22 Mobil Oil Corporation Additive for lubricants and hydrocarbon fuels comprising reaction products of olefins, sulfur, hydrogen sulfide and polymeric succinimide compounds
US4804776A (en) 1984-12-05 1989-02-14 Givaudan Corporation Process for the manufacture of benzene derivatives
US4822743A (en) 1984-12-13 1989-04-18 Lockheed Corporation Method and cloth for detecting leaks in closed bodies
US5089420A (en) 1990-01-30 1992-02-18 Miles Inc. Composition, device and method of assaying for a peroxidatively active substance utilizing amine borate compounds
US6121473A (en) 1998-02-19 2000-09-19 Massachusetts Institute Of Technology Asymmetric ring-closing metathesis reactions
US6277344B1 (en) 1998-01-14 2001-08-21 Ecolab Inc. Simultaneous use of peroxygen and olefin compound in odor reduction
US6423871B1 (en) 1999-02-26 2002-07-23 University Of South Florida Efficient synthesis of secondary amines by selective alkylation of primary amines
US6476191B1 (en) 1999-02-05 2002-11-05 Mixture Sciences, Inc. Volatilizable solid phase supports for compound synthesis
US20040031314A1 (en) 2002-08-13 2004-02-19 Patrick Flynn Hydrogen odorants and odorant selection method
US20040115818A1 (en) * 2002-12-16 2004-06-17 Puri Pushpinder Singh Leak detection by reactions at the leak site
US20040197919A1 (en) 2003-04-01 2004-10-07 Herman Gregory S. Fuel cell leak detection
US6820464B2 (en) 2002-12-16 2004-11-23 Air Products And Chemicals, Inc. Odorized seals for the detection of gas leak
US7024869B2 (en) 2002-12-16 2006-04-11 Air Products And Chemicals, Inc. Addition of odorants to hydrogen by incorporating odorants with hydrogen storage materials
US7192459B2 (en) 2002-12-16 2007-03-20 Air Products And Chemicals, Inc. Addition of odorants to gases for leak detection
US7229831B2 (en) 2002-12-16 2007-06-12 Air Products And Chemicals, Inc. Leak site odorization for gas leak detection
US20070246249A1 (en) 2003-11-27 2007-10-25 Takeyoshi Kano Metal Pattern Forming Methd, Metal Pattern Obtained by the Same, Printed Wiring Board, Conductive Film Forming Method, and Conductive Film Obtained by the Same
US7419635B2 (en) 2000-05-05 2008-09-02 Midwest Research Institute Pd/V2O5 device for colorimetric H2 detection

Patent Citations (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2416061A (en) 1943-10-27 1947-02-18 Du Pont Curing of polymers of substituted monoolefinic hydrocarbons with polyvalent metal compounds
US4657700A (en) 1983-10-07 1987-04-14 Givaudan Corporation Fragrance compositions containing benzyl ethers
US4804776A (en) 1984-12-05 1989-02-14 Givaudan Corporation Process for the manufacture of benzene derivatives
US4822743A (en) 1984-12-13 1989-04-18 Lockheed Corporation Method and cloth for detecting leaks in closed bodies
US4786425A (en) 1986-01-13 1988-11-22 Mobil Oil Corporation Additive for lubricants and hydrocarbon fuels comprising reaction products of olefins, sulfur, hydrogen sulfide and polymeric succinimide compounds
US5089420A (en) 1990-01-30 1992-02-18 Miles Inc. Composition, device and method of assaying for a peroxidatively active substance utilizing amine borate compounds
US6277344B1 (en) 1998-01-14 2001-08-21 Ecolab Inc. Simultaneous use of peroxygen and olefin compound in odor reduction
US6121473A (en) 1998-02-19 2000-09-19 Massachusetts Institute Of Technology Asymmetric ring-closing metathesis reactions
US6476191B1 (en) 1999-02-05 2002-11-05 Mixture Sciences, Inc. Volatilizable solid phase supports for compound synthesis
US6423871B1 (en) 1999-02-26 2002-07-23 University Of South Florida Efficient synthesis of secondary amines by selective alkylation of primary amines
US7419635B2 (en) 2000-05-05 2008-09-02 Midwest Research Institute Pd/V2O5 device for colorimetric H2 detection
US20040031314A1 (en) 2002-08-13 2004-02-19 Patrick Flynn Hydrogen odorants and odorant selection method
US20040115818A1 (en) * 2002-12-16 2004-06-17 Puri Pushpinder Singh Leak detection by reactions at the leak site
US6820464B2 (en) 2002-12-16 2004-11-23 Air Products And Chemicals, Inc. Odorized seals for the detection of gas leak
US7024869B2 (en) 2002-12-16 2006-04-11 Air Products And Chemicals, Inc. Addition of odorants to hydrogen by incorporating odorants with hydrogen storage materials
US7192459B2 (en) 2002-12-16 2007-03-20 Air Products And Chemicals, Inc. Addition of odorants to gases for leak detection
US7229831B2 (en) 2002-12-16 2007-06-12 Air Products And Chemicals, Inc. Leak site odorization for gas leak detection
US20040197919A1 (en) 2003-04-01 2004-10-07 Herman Gregory S. Fuel cell leak detection
US20070246249A1 (en) 2003-11-27 2007-10-25 Takeyoshi Kano Metal Pattern Forming Methd, Metal Pattern Obtained by the Same, Printed Wiring Board, Conductive Film Forming Method, and Conductive Film Obtained by the Same

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Guth, "Determination of the Configuration of Wine Lactone," Helvetica Chimica Acta, Sep. 1996, pp. 1559-1571, vol. 79, No. 6.
International Search Report and Written Opinion issued on Dec. 24, 2008 for International Application No. PCT/US08/12546 filed on Nov. 7, 2008 (8 pages).

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11953404B1 (en) * 2013-02-01 2024-04-09 Automotive Test Solutions, Inc. Composition of matter for identifying the location of a leak site
US11959831B1 (en) * 2013-02-01 2024-04-16 Automotive Test Solutions, Inc. Leak detection formula, analyze and methods of use
US10222291B2 (en) * 2013-03-07 2019-03-05 Automotive Test Solutions, Inc. Leak detection formula, analyzer and methods of use
US20140251831A1 (en) * 2013-03-07 2014-09-11 Kenneth D. Ley LEAK DETECTION FORMULA, ANALYZER and METHODS OF USE
US11828210B2 (en) 2020-08-20 2023-11-28 Denso International America, Inc. Diagnostic systems and methods of vehicles using olfaction
US11760170B2 (en) 2020-08-20 2023-09-19 Denso International America, Inc. Olfaction sensor preservation systems and methods
US12269315B2 (en) 2020-08-20 2025-04-08 Denso International America, Inc. Systems and methods for measuring and managing odor brought into rental vehicles
US11813926B2 (en) 2020-08-20 2023-11-14 Denso International America, Inc. Binding agent and olfaction sensor
US12017506B2 (en) 2020-08-20 2024-06-25 Denso International America, Inc. Passenger cabin air control systems and methods
US11881093B2 (en) 2020-08-20 2024-01-23 Denso International America, Inc. Systems and methods for identifying smoking in vehicles
US12251991B2 (en) 2020-08-20 2025-03-18 Denso International America, Inc. Humidity control for olfaction sensors
US11932080B2 (en) 2020-08-20 2024-03-19 Denso International America, Inc. Diagnostic and recirculation control systems and methods
US11760169B2 (en) 2020-08-20 2023-09-19 Denso International America, Inc. Particulate control systems and methods for olfaction sensors
US11636870B2 (en) 2020-08-20 2023-04-25 Denso International America, Inc. Smoking cessation systems and methods
US12037128B2 (en) 2021-03-23 2024-07-16 General Electric Company Safety markers for a hydrogen fuel system
US11732652B2 (en) 2021-03-23 2023-08-22 General Electric Company Removing safety markers from a hydrogen fuel system
US12018594B2 (en) 2022-03-07 2024-06-25 General Electric Company Pericritical fluid systems for turbine engines
US12264588B2 (en) 2022-03-07 2025-04-01 General Electric Company Liquid fluid systems including phase detection sensors for turbine engines
US11788474B2 (en) 2022-03-07 2023-10-17 General Electric Company Pericritical fluid systems for turbine engines
US11946378B2 (en) 2022-04-13 2024-04-02 General Electric Company Transient control of a thermal transport bus
US11927142B2 (en) 2022-07-25 2024-03-12 General Electric Company Systems and methods for controlling fuel coke formation
US12253033B2 (en) 2022-10-04 2025-03-18 General Electric Company Hydrogen fuel leak detection system for a vehicle

Also Published As

Publication number Publication date
US20090131617A1 (en) 2009-05-21
WO2009067146A1 (en) 2009-05-28
US7915047B2 (en) 2011-03-29
US20110165684A1 (en) 2011-07-07

Similar Documents

Publication Publication Date Title
US8470933B2 (en) Coating for leak detection and method
Zhang et al. Detection of reactive oxygen species in anion exchange membrane fuel cells using in situ fluorescence spectroscopy
US20040115818A1 (en) Leak detection by reactions at the leak site
FI60404B (en) PNEUMATIC DAECK VARS INRE YTA HAR ETT OEVERDRAG AV ETT SMOERJMEDELSGEL
EP2639577A1 (en) Electrochemical gas sensor comprising an anion-exchange membrane
BRPI0617157A2 (en) fuel source connectable to a fuel cell
CA2452465C (en) Leak site odorization for gas leak detection
CN101260051A (en) A biodegradable choline-based ionic liquid
Santambrogio et al. Effect of major degradation products of ethylene glycol aqueous solutions on steel corrosion
Yabuki et al. Effective release of corrosion inhibitor by cellulose nanofibers and zeolite particles in self-healing coatings for corrosion protection
US7024869B2 (en) Addition of odorants to hydrogen by incorporating odorants with hydrogen storage materials
US20230400415A1 (en) Self-healable chemical detecting sensor embedding transition metal-adsorbed paa-pva-borax fiber-gel
WO2005047879A1 (en) Liquid electrochemical gas sensor
Thorn et al. Coating for leak detection and method
KR100457789B1 (en) Adhesive tape for detecting leak gas
Chanthad et al. Effects of crosslinking time and amount of sulfophthalic acid on properties of the sulfonated poly (vinyl alcohol) membrane
Ding et al. The Effect of Temperature and Critical Micelle Concentrations (CMC) on the Inhibition Performance of a Quaternary Ammonium-Type Corrosion Inhibitor
Epstein Properties of GB in water
CA2452497C (en) Odorized seals for the detection of gas leak
CN101454660A (en) Inflammable substance sensor, and fuel cell provided therewith
KR20210112384A (en) Gas and/or chemical liquid indicators
JP7363875B2 (en) Water-based metal corrosion protection treatment method
CN215726657U (en) Gas and liquid leakage detection sensor
JP2006253040A (en) Fuel container and fuel cell system
WO2006011549A1 (en) Reagent for lead assay

Legal Events

Date Code Title Description
STCF Information on status: patent grant

Free format text: PATENTED CASE

FPAY Fee payment

Year of fee payment: 4

AS Assignment

Owner name: TRIAD NATIONAL SECURITY, LLC, NEW MEXICO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:LOS ALAMOS NATIONAL SECURITY, LLC;REEL/FRAME:047447/0201

Effective date: 20181031

FEPP Fee payment procedure

Free format text: 7.5 YR SURCHARGE - LATE PMT W/IN 6 MO, LARGE ENTITY (ORIGINAL EVENT CODE: M1555); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 8

FEPP Fee payment procedure

Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY