Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/20—Pills, tablets, discs, rods
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
  • B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
  • B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
  • B01J20/043—Carbonates or bicarbonates, e.g. limestone, dolomite, aragonite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
  • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
  • B01J20/103—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate comprising silica
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
  • B01J20/2803—Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
  • B01J20/28042—Shaped bodies; Monolithic structures
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/102—Carbon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/106—Silica or silicates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/20—Organic adsorbents
  • B01D2253/202—Polymeric adsorbents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents

Definitions

• the present invention relates to a gas-absorbing tablet for placement in confined spaces for absorbing deleterious acid gases.
• a more specific object of the present invention is to provide a gas-absorbing tablet which may be placed in an electronic apparatus enclosure for absorbing acid gases which may deleteriously affect the electronic components.
• the present invention relates to an acid-gas absorbing tablet comprising in relatively sufficient proportions by weight at least one adsorbent, a binder and a basic salt.
• the present invention also relates to a method of absorbing acid gases from an electronic device comprising the steps of preparing an acid-gas absorbing tablet comprising in relatively sufficient proportions by weight at least one adsorbent, a binder, and at least one basic salt, and installing said acid-gas absorbing tablet in said electronic device.
• a tablet which will absorb the organic and other acid gases which are generated. These gases include one or more of acetic acid, hydrogen sulfide and hydrochloric acid.
• the tablet comprises at least one adsorbent, a basic salt and a binder.
• a mold release agent including but not limited to silicone-free materials, can be mixed with the foregoing components for aiding in the removal of the molded tablet from the die which forms it.
• the tablet may be a rectangular solid having a length of about 3/4 of an inch, a width of about 1/4 inch and a height of about 1/4 inch, but it can have other dimensions.
• Preferred adsorbents are activated carbon or silica gel or a blend thereof in any proportions.
• the activated carbon or silica gel adsorbent or blend in any proportions may be present by weight in an amount of between about 73% and 93%, and more preferably between about 78% and 88%, and most preferably between about 80% and 85%.
• the activated carbon or silica gel or a combination in any proportion may have a particle size of between about 10 and 325 mesh, and more preferably between about 30 and 230 mesh, and most preferably between about 50 and 200 mesh. While the foregoing adsorbents are preferred, other adsorbents including indicating silica gel, molecular sieve and cellulose materials, without limitation, may be used.
• the preferred binder is polyvinylpyrrolidinone which may be present in an amount of between about 4% and 25%, and more preferably between about 8% and 17%, and most preferably between about 9% and 11%. Any standard tabletting binder may be substituted for the polyvinylpyrrolidinone.
• Other binders, without limitation, which may be used include sodium silicate, macrocrystalline cellulose, methyl cellulose, HPMC cellulose and CMC cellulose plus a variety of gum based adhesives . The foregoing listed binders act in the same manner as described hereafter as the polyvinylpyrrolidinone, namely, they will adsorb the acid gases and thereafter release them.
• the preferred basic salt is potassium carbonate, and it may be present in an amount of between about .2% and 8.4%, and more preferably between about .8% and 4%, and most preferably between about 1.5% and 2.5%.
• Basic salts having a Ph of between about 7 and 12 may be substituted for the potassium carbonate and such compounds include, without limitation, potassium bicarbonate, sodium bicarbonate and sodium carbonate.
• the potassium carbonate is mixed with the adsorbent, and its function is to absorb the major portion of the acid gases.
• the potassium carbonate combines chemically with the acid gas and produces carbon dioxide and water as byproducts. The water is adsorbed by the adsorbent and the carbon dioxide is released to the atmosphere.
• the preferred basic salt may be used by itself or in combination with another basic salt, as discussed hereafter.
• potassium bicarbonate Another basic salt which is preferably present is potassium bicarbonate, and it may be present in an amount of between about .5% and 7%, and more preferably between about 1.5% and 4%, and most preferably between about 2.5% and 3%.
• Other basic salts having a Ph of between 7 and 12 may be substituted for the potassium bicarbonate, and such compounds include, without limitation, potassium carbonate, sodium bicarbonate and sodium carbonate.
• the function of the potassium bicarbonate is to preferentially absorb acid gases directly and thereafter also absorb the acid gases which have been adsorbed by the binder and thereafter desorbed therefrom. The reason that potassium bicarbonate is used in addition to the potassium carbonate is because it mixes more readily with the binder.
• Potassium carbonate is preferentially used with the adsorbent due to its greater capacity to absorb the acid gases, thus maximizing the total acid-gas absorption capacity.
• potassium carbonate or any other suitable basic salt including but not limited to salts in the hydroxide and amine families, may be used with the binder, but a bicarbonate is preferred.
• the polyvinylpyrrolidinone adsorbs and releases the acid gases, and the bicarbonate thereafter chemically combines therewith and releases carbon dioxide and water. The water is adsorbed by the adsorbent, and the carbon dioxide is vented to the atmosphere.
• the gas-absorbing tablet may also contain water in an amount of up to 30%, and more preferably up to about 15%, and most preferably up to about 2%.
• a suitable amount of a die-releasing lubricant can be mixed with the composition and in this instance is comprised of aluminum stearate.
• Other suitable die-releasing agents may be used.
• a tablet has been formulated having the following composition by weight:
• Carbon includes but is not limited to activated nutshell or petroleum bases carbons, which may be commercially available treated or untreated carbon.
• Silica gel includes but is not limited to type A, B and AB .
• the above tablet has been fabricated in the following manner.
• the carbon or silica gel or a blend thereof in any proportion and potassium carbonate were blended in a planetary blender for approximately 10 minutes. Thereafter, the blend was permitted to set for about 24 hours.
• the mixing of the foregoing components may be achieved in any way for between 2 and 60 minutes, and the setting may be for anywhere between about 2 and 72 hours, as long as equilibrium is achieved during the time period.
• aluminum stearate was added and resulting composition was blended for approximately 5 minutes until well blended. However, the blending may be effected for between 1 minute and 30 minutes.
• the potassium bicarbonate and polyvinylpyrrolidinone were blended in a simple vane mixer until homogeneous.
• the mixture of potassium bicarbonate and polyvinylpyrrolidinone were added to the mixture of carbon or silica gel or a blend thereof with the potassium carbonate and all these ingredients were blended in a sigma mixer at a temperature of about 54° C. for approximately two hours until the mixture was well blended and ready for tabletting.
• the mixing can be effected in any suitable time of between about one hour and eight hours and the final temperature range can be between about 10° C. and 180° C.
• the tabletting of the final mixture was effected in a tablet press at a pressure of between about 5,000 and 12,000 pounds per square inch.
• the mixing procedure is essentially the same in that the substituted compound is separately mixed with the polyvinylpyrrolidinone for the purpose of insuring intimate contact therewith. Therefore, even though separate mixings have been effected, there may only be one basic salt present if potassium carbonate was substituted for the potassium bicarbonate.
• the above-described tablet functions in the following manner.
• the basic salt which was mixed with the adsorbent absorbs the acid gases by converting the acid gases to nondeleterious substances.
• the chemical reaction of the basic salt and an acid gas produces a salt plus carbon dioxide gas plus water.
• the carbon dioxide gas is vented to the atmosphere, and the water is adsorbed by the adsorbent and ultimately released to the atmosphere when the adsorbent is heated during operation of the hard drive or the electronic or computer device.
• the polyvinylpyrrolidinone binder will adsorb the acid gas, but there will be no chemical change as when the acid gas reacts with the basic salt, as described above.
• the acidic gas will be desorbed from the binder and pass into the portion of the tablet outside of the binder where the basic salt is present in the tablet, and the basic salt will then absorb the acid gas in the above- described manner.
• the basic salt which operates most efficiently is the potassium bicarbonate which mixes more readily with the polyvinylpyrrolidinone than the potassium carbonate.
• the charts below show the tablets ' performance in retaining an organic acid.
• three 8-10 mg samples in which the adsorbent was 100% activated carbon in the above specific formulation containing potassium carbonate, potassium bicarbonate and polyvinylpyrrolidinone were tested on a Dynatherm tester and the results were plotted in the following charts.
• the testing showed that the average of three specimens absorbed 139 micrograms of acetic acid and only 6 micrograms were desorbed after having been subjected to twenty-six desorption cycles.
• the percent of the original amount of acid absorbed and thereafter released by the tablet was less than about 5%.
• GRAPH A and GRAPH B both entitled "Organic Acid Desorption".
• each cycle consisted of subjecting each sample (8-10 mg) to a specific heat for four minutes.
• the temperature of each cycle is shown in the following table wherein each cycle is listed sequentially.
• the first three sequential cycles were each performed for four minutes at 100° C, 125° C. and 150° C, respectively. Thereafter, there were three sequential four minute cycles at 200° C, 225° C, 250° C, etc. for a total of 26 cycles. In other words, each specimen was subjected to twenty-six sequential four minute cycles, and the amount of acid gas desorbed was measured. Each plot shows the cumulative amount of acid gas desorbed. In other words, the graphs do not show the specific amount desorbed at each cycle, but the total amount desorbed to the end of that cycle.
• the following GRAPH B relates to the same subject matter. However, the plot is the percent of original mass desorbed plotted against desorption cycles.
• the foregoing GRAPHS A and B show the desorption characteristic of the above tablet which contains the KHC0 3 • The significance of the KHCO 3 can be appreciated when the above GRAPHS A and B are compared to the following GRAPHS C and D wherein the tablet did not contain the KHCO 3 .
• the tablet of GRAPHS C and D contained adsorbent in the amount of 87% (which was 100% activated carbon) and potassium carbonate in the amount of 2% and 9% polyvinylpyrrolidinone and 1% aluminum stearate and 1% water.
• the potassium carbonate was mixed only with the adsorbent, and this mixture was thereafter mixed with the polyvinylpyrrolidinone.
• GRAPH A when GRAPH A is compared to GRAPH C, it can be seen that the total amount desorbed in GRAPH A is 6.3 micrograms as compared to 75 micrograms in GRAPH C, thereby illustrating the capacity of the KHCO 3 to greatly limit desorption.
• GRAPH B wherein 4.5% of the original mass is desorbed as compared to GRAPH D wherein 52% of the original mass is desorbed.
• absorb and "absorbing” used above are intended to mean that the gas is chemically changed as a result of the reaction, whereas the terms adsorb and desorb are intended to mean that the gas is not chemically changed as a result of being combined with and released from, respectively, the binder and the adsorbent.

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• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
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• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Pharmacology & Pharmacy (AREA)
• Medicinal Chemistry (AREA)
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• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Treating Waste Gases (AREA)
• Gas Separation By Absorption (AREA)

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• 2001
  • 2001-01-23 US US09/768,016 patent/US7083804B2/en not_active Expired - Fee Related
  • 2001-11-26 WO PCT/US2001/044291 patent/WO2002058675A1/en not_active Ceased
  • 2001-11-26 CN CNB018222021A patent/CN100469354C/zh not_active Expired - Fee Related
  • 2001-11-26 JP JP2002559009A patent/JP2004517726A/ja active Pending
  • 2001-11-26 KR KR1020037009694A patent/KR100895731B1/ko not_active Expired - Fee Related
• 2006
  • 2006-07-14 US US11/487,556 patent/US7892527B2/en not_active Expired - Fee Related
  • 2006-07-14 US US11/487,555 patent/US7842287B2/en not_active Expired - Fee Related

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