WO1988005911A1 - Capteurs optiques de monoxyde de carbone appliques par impregnation sur des substrats monolithiques poreux - Google Patents

Capteurs optiques de monoxyde de carbone appliques par impregnation sur des substrats monolithiques poreux Download PDF

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Publication number
WO1988005911A1
WO1988005911A1 PCT/US1988/000217 US8800217W WO8805911A1 WO 1988005911 A1 WO1988005911 A1 WO 1988005911A1 US 8800217 W US8800217 W US 8800217W WO 8805911 A1 WO8805911 A1 WO 8805911A1
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WO
WIPO (PCT)
Prior art keywords
chloride
group
perchlorate
acid
reagent system
Prior art date
Application number
PCT/US1988/000217
Other languages
English (en)
Inventor
Mark Kingston Goldstein
Terry Grant Anderson
James Howard Meadows
Diane Taylor
Original Assignee
Quantum Group, Inc.
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 Quantum Group, Inc. filed Critical Quantum Group, Inc.
Publication of WO1988005911A1 publication Critical patent/WO1988005911A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
    • G01N21/783—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour for analysing gases
    • 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
    • G01N31/223—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 for investigating presence of specific gases or aerosols
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
    • G01N33/004—CO or CO2
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Definitions

  • the present invention relates to an improved device for detecting the presence of a reducing gas by means of a chemical reagent system which changes optical density in response to the presence of reducing gas.
  • the device is of particular use in detecting the presence of carbon monoxide or hydrogen sulfide.
  • the present invention comprises a device for detecting the presence of a reducing gas, which has a working Life of at least one year.
  • the device comprises a porous monolithic substrate sufficiently transmissive to light to permit its detection by a phototransistor or the like, and a self-regenerating chemical reagent system impregnated in the substrate, which changes optical density in response to contact with the reducing gas.
  • the improvement which results in the increased working life of the chemical reagent system lies in the inclusion in the chemical reagent system of a compound(s) which renders the chemical reagent system acid-retaining and/or acid-forming.
  • the present invention further comprises an improved chemical reagent system for the detection of the presence of a reducing gas.
  • the present invention comprises an improved device for detecting the presence of a reducing gas, the device comprising a porous, monolithic substrate sufficiently transmissive to light to permit its detection by a phototransistor or the like; and a self-regenerating chemical reagent system which changes optical density in response to contact with the reducing gas to be detected, said chemical reagent system being impregnated into the substrate, the improvement comprising including in the chemical reagent system a compound(s) which renders the chemical reagent system acid-retaining and/or acid-forming.
  • the compound(s) is preferably water soluble and is preferably selected from the group consisting of lithium chloride, sodium chloride, lithium sulfate, lithium perchlorate, magnesium perchlorate, calcium perchlorate, aluminum perchlorate, platinum chloride, an inorganic acid, calcium chloride, magnesium chloride, cobalt chloride and combinations thereof. It is particularly preferred that ' the compound(s) is a nonvolatile inorganic acid, such as sulfuric acid or perchloric acid, or a halide salt such as calcium chloride, cobalt chloride and platinum chloride. It is preferable that the compound(s) is such that hydrochloric acid is either formed or retained in the chemical reagent system.
  • the porous monolithic substrate may be any of a number of commercially available porous monolithic materials which are optically transmissive. Examples include, but are not limited to, commercial silica gel dessicants in bead form (available from most major supplies of silica gel) , porous silicon dioxide and porous leached borosilicate glass such as VYCOR ("thirsty glass” — Corning Glass Works, Corning, New York. Brand No. 7930) .
  • the porous glass may b e obtained in plate, rod or tubing form. Discs may be obtained by slicing the rods to suitable form. A variety of physical shapes and forms for the substrate may be obtained by suitable commercial processes.
  • the chemical reagent system used to impregnate the porous monolithic substrate may be composed of compounds disclosed in U.S. Patent No. 4,043,934. It is preferable that the chemical reagent system comprises a selection of at least one compound from each of the following groups:
  • Group 2 silicomolybdic acid, salts of silicomolybdic acid, molybdenum trioxide, hetropolyacids of molybdenum, ammonium molybdate, alkali metal or alkaline earth metal salts of the molybdate anion; Group 3 - copper sulfate, copper chloride, copper bromide, copper iodide, and copper perchlorate; plus the compound(s) which renders the chemical reagent system acid retaining and/or acid forming.
  • the chemical reagent system used in the present invention comprises palladium chloride, silicomolybdic acid, copper chloride, and, as the acid-retaining and/or acid-forming chemical, calcium chloride.
  • the device further includes a hygroscopic agent, which is preferably a chloride. It is particularly preferred that the hygroscopic agent comprises a non-volatile source of halide.
  • the device includes absorbants to protect the sensor from external contaminants and/or to inhibit the loss of acid and water from the sensor.
  • the porous monolithic substrate is impregnated with the chemical reagent system by immersing the substrate in a bath including at least one compound from each of the following groups:
  • Group 1 palladium sulfate, palladium chloride, palladium bromide, palladium iodide, and palladium perchlorate;
  • Group 2 silicomolybdic acid, salts of silicomolybdic acid, molybdenum trioxide, hetropolyacids of molybdenum, ammonium molybdate, alkali metal or alkaline earth salts of the molybdate anion;
  • Group 3 copper sulfate, copper chloride, copper bromide, copper iodide, artd copper perchlorate;
  • Group 4 lithium chloride, sodium chloride, • lithium sulfate, lithium perchlorate, magnesium perchlorate, calcium perchlorate, aluminum perchlorate, platinum chloride, an inorganic acid, calcium chloride, magnesium and cobalt chloride.
  • the substrate is then removed from the bath and allowed to dry.
  • the bath includes compounds from each group in the following ratio range:
  • Group 1 Group 2 - 0.01:1 to 0.5:1
  • Group 3 Group 2 - 0.001:1 to 0.08:1
  • Group 4 Group 2 - 0.01:1 to 10.0:1
  • the Group 4 compound is calcium chloride.
  • the compound(s) selected from Group 4 is present in at least a stoichemetric amount compared to the compound selected from Group 3.
  • Sensor devices were made by soaking pieces of porous VYCOR and silica gel beads for several hours in the following solutions and then letting the pieces dry in air. Measurements of optical response were made using standard laboratory instruments during periodic exposures to CO. Several example preparations of the monolithic sensors are presented below. Examples 1 through 3 were prepared by immersion of VYCOR into solution, the VYCOR is then removed and dried. Example 4 was made by placing porous silica beads in solution and then evaporating the solution.
  • the porous VYCOR discs have a diameter of approximately 0.25 inches and a thickness of 0.050 to 0.20 inches.
  • Example 4 and exposed to ambient conditions in excess of two years are proving to respond subsequently to low levels of CO in air and regenerate for over 40 cycles.
  • Sensors prepared according to Example 2 are proven to have lifetimes in excess of eight months. When such sensors are properly protected from environmental contaminants and heat they are expected to be capable of affording useful lifetimes of several years.
  • One year is a commercially feasible minimum lifetime requirement for most chemical sensors application such as CO safety shutoff systems for gas appliances and CO alarm systems.
  • CO sensors prepared with porous, monolithic VYCOR substrates therefore exhibit the lifetime requirements for a variety of commercial applications.
  • the observed enhancement of sensor lifetime may be due to an acid retaining and/or chloride acid replacement capability of the new formulation and the longer path for the volatile acid to exit this substrate. This may create a tortuous path by which molecules enter and leave the monolithic substrate, thus increasing substrate lifetime either by slowing down the departure of volatile components and/or by replacing the acid with excess acid forming compounds such as soluble chlorides. Tests in our lab indicate silica gel lifetime is extended with the addition of the agents, however, porous substrate life extension is even greater.
  • the effective pore diameters of the monolithic materials may be important in extending the useful lifetimes of the sensors, presumably by promoting the retention of acid and water. Tests indicate 10 to 100 angstroms pore size are preferred. Porous leached VYCOR is reported to have an average pore diameter of 40 angstroms with a void space of about 28% of its total volume. The silica gel beads are believed to have typical pore diameters of approximately 25 angstroms. Pore diameters between approximately 15 and 50 angstroms r are believed to facilitate the retention of acid and water. Surface area may be another important physical property of porous substrates. Porous VYCOR is reported to have a surface area of approximately 200 square meters/gram. Since this is a value typical of many powdered silica gel substrates, the surface area of VYCOR is not believed to contribute to its observed enhanced lifetime properties.
  • the sensitivity of our porous, monolithic sensors is not diminished by going to such substrates. They respond to low levels of CO at least as well as the powdered silica gel sensors of U. S. 4,043,934.
  • the sensors typically show at least a fivefold drop in transmitted near-infrared radiation (as detected by silicon-based photo detectors) under the following conditions: 200 ppm CO (response ⁇ 2 hours) ; 40 ppm CO (response ⁇ 30 minutes) .
  • the monolithic nature of the sensor also facilitates light transmission through the sensor.
  • Porous VYCOR and silica gel beads provide at least a tenfold increase in light transmission over powdered silica gel sensors of comparable thickness.
  • the increased light transmission permits the use of low-cost conventional photo detectors which do not display significant temperature dependence.
  • Our porous, monolithic sensors are therefore more amenable to commercial applications than are powdered silica gel sensors.
  • porous, monolithic sensors also show other significant advantages over powdered silica gel sensors.
  • Powdered silica gel substrates have a tendency to swell or contract appreciably depending upon the water content of the material. This property can affect the quality of particle packing within the sensor and can introduce cracking and light leaks.
  • the bodies of porous, monolithic sensors are much more rigid and show little tendency to change their shape or size depending upon their water content. Futhermore, expensive porous windows required to retain the silica gel are not necessary to retain the porous, monolithic sensor. The physical properties of porous, monolithic sensors therefore making them more reliable and low-cost alternative to powdered silica gel sensors.
  • inorganic non volatile acids such as perchlorate and halide salts such as, CaCl , CoCl 2 , and/or PtCl 2
  • inorganic non volatile acids such as perchlorate and halide salts such as, CaCl , CoCl 2 , and/or PtCl 2
  • nonvolatile inorganic halides among the above group are also believed to extend the sensor lifetime by facilitating the retention of halide (chloride) in the sensor.
  • Halide is believed to be important in maintaining the reversible nature of the sensor.
  • the device of the present invention may be incorporated in a system for the detection of the presence for reducing gas. This may be done by providing a radiation source arranged such that radiation from the source is incident upon the device of the present invention and providing detection means for measuring the amount of radiation passing through the device of the present invention.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Engineering & Computer Science (AREA)
  • Pathology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Molecular Biology (AREA)
  • Biophysics (AREA)
  • Dispersion Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Plasma & Fusion (AREA)
  • Combustion & Propulsion (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)

Abstract

Dispositif perfectionné permettant de détecter la présence d'un gaz réducteur tel du monoxyde de carbone ou du sulfure d'hydrogène. Le dispositif comprend un substrat monolithique poreux suffisamment transparent à la lumière pour en permettre la détection à l'aide d'un phototransistor, et un système réactif chimique autorégénérateur dont la densité varie lorsqu'il entre en contact avec le gaz réducteur dont est imprégné le substrat. Le système réactif chimique comprend un ou plusieurs composés lui conférant des caractéristiques de rétention d'acide et/ou de formation d'acide.
PCT/US1988/000217 1987-02-04 1988-01-27 Capteurs optiques de monoxyde de carbone appliques par impregnation sur des substrats monolithiques poreux WO1988005911A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US1078687A 1987-02-04 1987-02-04
US010,786 1987-02-04

Publications (1)

Publication Number Publication Date
WO1988005911A1 true WO1988005911A1 (fr) 1988-08-11

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0617275A1 (fr) * 1993-03-24 1994-09-28 Eurodif Production Détecteur de vapeurs d'acide ou d'hexafluorure d'uranium
US5486336A (en) * 1990-06-12 1996-01-23 Catalytica, Inc. NOX sensor assembly
EP0699903A1 (fr) * 1994-09-05 1996-03-06 Japan Pionics Co., Ltd. Réactif pour la détection des hydrases gazeux
EP0746755A1 (fr) * 1993-01-26 1996-12-11 Fci-Fiberchem, Inc. Detecteur de monoxyde de carbone a semiconducteurs
EP0779975A1 (fr) * 1994-08-29 1997-06-25 Quantum Group Inc. Detecteurs de monoxyde de carbone organometalliques bioderives absorbant les photons
EP0884590A1 (fr) * 1997-06-12 1998-12-16 Quantum Group Capteurs de monoxide de carbone avec un seuil de réponse contrÔlé
EP0901009A2 (fr) * 1997-08-29 1999-03-10 Nippon Telegraph and Telephone Corporation Procédé, élément de capteur, et capteur de gaz pour la détection du dioxyde d'azote
US8956571B2 (en) 2006-04-13 2015-02-17 Quantum Group Inc. Carbon monoxide sensor system and related methods

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3672845A (en) * 1970-07-28 1972-06-27 Miles Lab Test device for albumin
US4043934A (en) * 1974-07-24 1977-08-23 The Regents Of The University Of California Catalyst and method for oxidizing reducing gases
US4351662A (en) * 1981-06-25 1982-09-28 Corning Glass Works Method of making photosensitive porous glass

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3672845A (en) * 1970-07-28 1972-06-27 Miles Lab Test device for albumin
US4043934A (en) * 1974-07-24 1977-08-23 The Regents Of The University Of California Catalyst and method for oxidizing reducing gases
US4351662A (en) * 1981-06-25 1982-09-28 Corning Glass Works Method of making photosensitive porous glass

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Analytical Chemistry, Vol. 19, No. 2, published February 1947, SHEPHERD, "Rapid Determination of Small Amounts of Carbon Monoxide", see pages 77-81. *
Journal of Analytic Chemistry of the USSR, Vol. 40, No. 9, published September 1985, MESHKOVSKI et al., "Colorimetric Porous Indicator of Carbon Dioxide", pages 1285-1288. *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5486336A (en) * 1990-06-12 1996-01-23 Catalytica, Inc. NOX sensor assembly
EP0746755A4 (fr) * 1993-01-26 1997-11-12 Fiberchem Inc Detecteur de monoxyde de carbone a semiconducteurs
EP0746755A1 (fr) * 1993-01-26 1996-12-11 Fci-Fiberchem, Inc. Detecteur de monoxyde de carbone a semiconducteurs
FR2703158A1 (fr) * 1993-03-24 1994-09-30 Eurodif Production Détecteur de vapeurs d'acide fluorhydrique.
EP0617275A1 (fr) * 1993-03-24 1994-09-28 Eurodif Production Détecteur de vapeurs d'acide ou d'hexafluorure d'uranium
EP0779975A4 (fr) * 1994-08-29 1997-12-29 Quantum Group Inc Detecteurs de monoxyde de carbone organometalliques bioderives absorbant les photons
EP0779975A1 (fr) * 1994-08-29 1997-06-25 Quantum Group Inc. Detecteurs de monoxyde de carbone organometalliques bioderives absorbant les photons
US5665313A (en) * 1994-09-05 1997-09-09 Japan Pionics Co., Ltd. Detecting agent
EP0699903A1 (fr) * 1994-09-05 1996-03-06 Japan Pionics Co., Ltd. Réactif pour la détection des hydrases gazeux
EP0884590A1 (fr) * 1997-06-12 1998-12-16 Quantum Group Capteurs de monoxide de carbone avec un seuil de réponse contrÔlé
EP0901009A2 (fr) * 1997-08-29 1999-03-10 Nippon Telegraph and Telephone Corporation Procédé, élément de capteur, et capteur de gaz pour la détection du dioxyde d'azote
EP0901009A3 (fr) * 1997-08-29 1999-04-14 Nippon Telegraph and Telephone Corporation Procédé, élément de capteur, et capteur de gaz pour la détection du dioxyde d'azote
US6362005B1 (en) 1997-08-29 2002-03-26 Nippon Telegraph And Telephone Corporation Nitrogen dioxide gas sensing method, nitrogen dioxide gas sensor element, and nitrogen dioxide gas sensor using the same
US8956571B2 (en) 2006-04-13 2015-02-17 Quantum Group Inc. Carbon monoxide sensor system and related methods

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