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Topic: Acid catalyst


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In the News (Fri 24 May 19)

  
  Sulfuric acid - Wikipedia, the free encyclopedia
Sulfuric acid is a constituent of acid rain, being formed by atmospheric oxidation of water and sulfur dioxide.
A mixture of sulfuric acid and water is used as the electrolyte in various types of lead-acid battery where it undergoes a reversible reaction where lead and lead dioxide are converted to lead(II) sulfate.
Fires near or involving sulfuric acid are usually fought using foam or dry earth agents, to avoid the possibilty of the acid boiling.
en.wikipedia.org /wiki/Sulphuric_acid   (1985 words)

  
 [No title]
When catalyst activity is unacceptable, the reactor is taken out of service and typically undergoes a hydrogen sweep to burn residual hydrocarbon, then a nitrogen sweep to cool the reactor and remove occupational hazards such as hydrogen sulfide and benzene.
A portion of the acid catalyst is continuously bled and replaced with fresh acid to maintain the reactor's acid concentration at around 90 percent.
Dimersol and phosphoric acid catalysts were categorized together in the consent decree, therefore, a summary of the results for both residuals is presented in Table 3.7.7.
www.epa.gov /epaoswer/hazwaste/id/studies/studyp.txt   (17268 words)

  
 World Intellectual Property Organization   (Site not responding. Last check: 2007-10-19)
Examples of the acid catalyst which can be used in the present invention include compounds widely known in general as an acid catalyst, such as a heteropolyacid and a salt thereof, an ion-exchange resin, a mineral acid, zeolite and a composite metal oxide.
If the acid catalyst content exceeds 200 mass%, the effective surface area decreases and, as a result, the effect obtainable by the increase in the supported amount may not be brought out and at the same time, coking is readily generated to greatly shorten the catalyst life.
For example, the catalyst may be prepared by dissolving or suspending a heteropolyacid and/or a heteropolyacid salt in a solvent to obtain a solution or suspension corresponding to the liquid absorption amount of a support and impregnating the solution or suspension into the support.
www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=03/106398.031224&ELEMENT_SET=DECL   (4565 words)

  
 Process for regenerating fluorosulfuric acid catalyst - Patent 4096199
In a preferred embodiment, at least a portion of the regenerated fluorosulfuric acid is recycled to the alkylation zone for use as an alkylation catalyst therein.
Hence, when the catalyst system is described as "being formed from" a strong acid and a moderator, it is not meant to be limited to any one catalyst formation mode; rather, this description is used merely for convenience in providing a simple definition of the active catalyst system.
Regenerated fluorosulfuric acid, which may contain small amounts of water, is withdrawn from contacting/stripping zone 34 via line 44 and at least a portion thereof is combined with the recycle stream 14 for return to alkylation zone 6 via line 8.
www.freepatentsonline.com /4096199.html   (5911 words)

  
 World Intellectual Property Organization   (Site not responding. Last check: 2007-10-19)
In the method of the present invention the hydrolysis of the fatty acid ester to the corresponding fatty acid is carried out in the presence of a solid acid catalyst, in particular a catalyst selected from the group of zeolites, ion exchange resins and acid amorphous catalysts.
The catalyst, in particular when used as a fixed bed catalyst, may be used in the form of an extrudate, spheres, tablets or any other form the mechanical strength of which is satisfactory for use with the process of this invention.
The fatty acid ester is hydrolyse to the corresponding fatty acid and alcohol.
www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=03/87027.031023&ELEMENT_SET=DECL   (3028 words)

  
 United States Patent: 5,831,120
Wet acetic acid is removed from the light ends column as a side draw and is fed to the drying column where water is removed overhead and an essentially dry acetic acid stream is removed from the base of the distillation zone.
Such off-specification, water-contaminated acetic acid may be purified by feeding a process stream of water-contaminated acetic acid to the process, for example to the drying column of the process, from which water is recycled to the carbonylation reactor.
When rhodium is used as catalyst the rate at which the water-contaminated, off-specification acetic acid may be fed to the process is limited by the rate at which water is consumed by the water gas shift reaction in the carbonylation reactor, otherwise water will accumulate in the liquid reaction composition in the carbonylation reactor.
www.englib.cornell.edu /instruction/chemengr462/images/pto4.html   (5160 words)

  
 Recovery of vanadium and copper catalysts from adipic acid production   (Site not responding. Last check: 2007-10-19)
Traditionally, ADA is made by hydrogenation of phenol to cyclophexanol or by oxidation of cyclohexane to a mixture of cyclohexanone and cyclophexanol (also known as KA oil) in the presence of a cobalt or a boric acid catalyst.
The cyclophexanol or KA oil is further oxidized to adipic acid with nitric acid in the presence of copper and vanadium salts as catalysts.
Catalyst and nitric acid are recovered and recycled, organic acid by-products are used for the production of polyester polyols which are consumed in the polyurethane production.
www.rohmhaas.com /ionexchange/IP/catalyst_recovery.htm   (239 words)

  
 Process for making quinacridone and its derivatives - Patent 4064129
A commercially important process for making quinacridones involves the acid catalyzed ring closure of 2,5-diarylaminoterephthalic acids in polyphosphoric acid which is usually a preferred solvent for effecting the ring closure since it functions as both solvent and acid catalyst and is exemplified in U.S. Pat.
The acid catalysts that may be used include, but are not limited to, the mono- or di-sulfonic acids of benzene, toluene, xylene, paradichlorobenzene, naphthalene, nitrobenzene and chloroparaxylene.
Generally, the acid catalyst is used in a range of about 0.1 to about 4 parts per part of 2,5-diarylaminoterephthalic acid, the preferred range being from about 0.2 to 1.5 parts per part of 2,5-diarylaminoterephthalic acid.
www.freepatentsonline.com /4064129.html   (4467 words)

  
 Catalyst: Lactic Acid - ABC TV Science
Lactic Acid is blamed for that painful burning sensation you feel when you’ve pushed yourself a bit too far exercising.
Lactic acid was identified as a suspect cause for fatigue in a famous experiment performed in 1929.
The sportspeople will probably be divided about the latic acid research for some time but for most people it just doesn't apply as when it comes to exercise it's their minds that give up and not their muscles.
www.abc.net.au /catalyst/stories/s1314443.htm   (1102 words)

  
 Acid catalyst - Wikipedia, the free encyclopedia
In organic chemistry, an acid catalyst is a compound such as sulfuric acid (H
Usually this is done to create a more likely leaving group, such as converting an OH to a H
Acid catalyzed reactions are usually reversible, as contrasted with base catalyzed reactions, which are usually irreversible.
en.wikipedia.org /wiki/Acid_catalyst   (75 words)

  
 Aroylation of aromatics with arylcarboxylic acids over Nafion-H (polymeric perfluoroalkanesulfonic acid), an ...   (Site not responding. Last check: 2007-10-19)
Nafion-H, a perfluoroalkanesulfonic acid resin, has been found to be a suitable solid acid catalyst with high selectivity, and catalytic activity giving good yields of products.
This solid perfluoroalkanesulfonic acid resin catalyst is more convenient and environmentally friendly in comparison with corrosive acid catalysts (liquid acids) generally used in reactions involving strong acids.
Reactions were carried out with the corresponding carboxylic acid in excess of the arene under reflux (175-180 °C) using a Dean-Stark apparatus for efficient water removal.
www.arkat-usa.org /ark/journal/2004/I08_Narasimhan/1100/1100.asp   (1522 words)

  
 Environmental Defense - Alkylation and Reforming
Vast quantities of sulfuric acid are required for catalytic alkylation, and the used (or "spent") acid frequently is recycled into fresh material rather than discarded.
To prevent the risks associated with the transportation of sulfuric acid and the on-site accident dangers associated with the use of hydrofluoric acid, a solid acid catalyst that has recently been proven effective for refinery alkylation can be used.
A solid acid catalyst for alkylation is much less able than HF to disperse into the environment in a short time frame.
www.environmentaldefense.org /article.cfm?ContentID=1571   (441 words)

  
 NETL/CCTC: SNOX™ Flue Gas Cleaning Demonstration Project - Summary
Because the SO catalyst followed the NOx catalyst, any unreacted ammonia (slip) was oxidized in the SO catalyst to nitrogen, water vapor, and a small amount of NOx.
Space velocity governed the amount of catalyst necessary at design flue gas flow conditions, and gas and bed temperature had to be high enough to activate the SO oxidation reaction.
Sulfuric acid concentration and composition met or exceeded the requirements of the federal specifications for Class I acid.
www.netl.doe.gov /cctc/summaries/snox/snoxtmdemo.html   (1581 words)

  
 Additional suggested operating instructions for manufacturing Elvaloy® RET modified asphalt, using catalyst ...
If phosphoric acid with a purity above 105% is to be used, it is important to heat the drums, pump, and acid transfer line to lower the viscosity to manageable levels.
To prevent the acid from absorbing moisture from the air, drums should not be left open to the atmosphere.
Acid should be received by tank truck or rail car, and pumped into a 316 stainless steel tank or equivalent.
www.dupont.com /asphalt/H-81614.html   (2561 words)

  
 INEEL develops safe, efficient process for making cleaner-burning fuels
Instead of using a liquid catalyst, the team generates alkylate using a solid acid catalyst to change low-octane gaseous feedstock into liquid alkylate.
The solid zeolite catalyst is porous, providing a lot of surface area to catalyze the reactions that change butane/butene petroleum gases into liquid alkylate.
The catalyst surface, however, eventually becomes coated with undesirable hydrocarbons that effectively deactivate the catalyst, and are a challenge to "clean." Burning the hydrocarbons off-the traditional approach for solid catalysts-turns out to be too harsh and quickly destroys the catalyst activity.
www.eurekalert.org /pub_releases/2001-08/ine-ids080901.php   (1248 words)

  
 Abstract
When an acid catalyst is used, one should heat the reaction to just below the alcohol’s boiling point and heat the reaction for sixty-nine hours.
If it is decided that an acid catalyst is to be used, it is still necessary to determine how much acid catalyst should be used.
A one-percent acid catalyst for a forty-eight hour reaction time could produce a methyl ester yield of 72.7% while a 5% acid catalyst produced a 95% yield.
www.wiu.edu /users/jtf103/exampleofwork.htm   (1423 words)

  
 Exelus Solid Acid Catalyst Technology – ExSact - Exelus Inc.   (Site not responding. Last check: 2007-10-19)
ExSact is a new technology to convert light (C3 -C5) hydrocarbons to high-octane gasoline blend-stock (alkylate) using solid-acid catalysts as a viable alternative to conventional liquid-acid (sulfuric and hydrofluoric) catalyzed processes.
Exelus has developed a revolutionary solid acid catalyst that is easily able to achieve a quantum jump in performance over conventional solid-acid catalysts.
The robust solid-acid catalyst produces alkylate with a superior octane rating (>95 RON) over a wide range of operating temperatures (50-100°C), olefin space velocities (0.1 to 1.0 1/hr) and feed composition (I/O ratios from 6 to 30).
exelusinc.com /exsact.shtml   (279 words)

  
 Haldor Topsoe - Products & Services - Catalysts - Sulphuric Acid - Catalyst Types
Today, Topsoe’s VK Series of sulphuric acid catalysts provides a choice of 5 catalysts in different shapes and sizes to efficiently meet all the needs of modern sulphuric acid plants.
The different requirements in the various parts of the sulphuric acid converter typically dictate the use of several catalyst types.
The optimal choice of catalyst is based on activity requirements, pressure drop considerations and ignition temperature.
www.topsoe.com /site.nsf/all/BBNN-5PFH4W?OpenDocument   (103 words)

  
 DuPont Stratco | Alkylation   (Site not responding. Last check: 2007-10-19)
HF properties are much different from the properties of sulfuric acid catalyst, and therefore, the optimum reaction conditions are different.
The major process differences in a sulfuric acid alkylation unit are lower reaction temperatures and pressures, higher mixing energies, and effluent treatment of the reactor effluent prior to fractionation.
The HF unit's facilities for acid regeneration, KOH regeneration, disposal of acid soluble oils (ASO), disposal of calcium fluoride, sodium fluoride and spent caustic are eliminated.
www.stratco.dupont.com /alk/alkylation_08.html   (2689 words)

  
 EPA and NSF Technology for a Sustainable Environment (TSE) Grantees Meeting   (Site not responding. Last check: 2007-10-19)
New solid acid catalysts developed for hydrocarbon processes have shown promise in replacing liquid acids, but they typically suffer from low acid site density on a volumetric basis (compared to liquid acids) and from rapid deactivation due to carbon deposition on the catalyst.
The hydration state of phosphotungstic acid (H3PW12O40) was explored through the use of in situ Fourier transform infrared (FT-IR) spectroscopy, water sorption microcalorimetry, and density functional theory (DFT) quantum chemical calculations.
Proton mobility may be critical to the activity of an acid catalyst.
www.scgcorp.com /nsf2004/davis.asp   (1091 words)

  
 70071S02
For nearly three decades, major oil companies have been active in developing solid acid catalysts as an alternative to the hazardous liquid acids.
During Phase I, the new class of solid acid catalysts will be synthesized, characterized, and tested for paraffin alkylation.
The new alkylation process would eliminate safety and maintenance concerns associated with using liquid acids and would be an economically viable alternative to installing mitigation and other safety equipment for modernizing an existing hydrogen fluoride alkylation unit.
www.er.doe.gov /sbir/awards_abstracts/sbirsttr/cycle20/phase1/045.htm   (236 words)

  
 AllRefer.com - acids and bases (Chemistry) - Encyclopedia
You are here : AllRefer.com > Reference > Encyclopedia > Chemistry, General > acids and bases
acids and bases, two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water.
More articles from AllRefer Reference on acids and bases
reference.allrefer.com /encyclopedia/A/acidsNba.html   (138 words)

  
 mechanism for the hydration of ethene
Ethene is mixed with steam and passed over a catalyst consisting of solid silicon dioxide coated with phosphoric(V) acid.
All of the hydrogen atoms in the phosphoric(V) acid are fairly positively charged because they are attached to a very electronegative oxygen atom.
The catalyst used on that page is concentrated sulphuric acid rather than phosphoric(V) acid, because that is the acid often used in the lab.
www.chemguide.co.uk /physical/catalysis/hydrate.html   (680 words)

  
 Sulphur: Monsanto and sulphuric acid catalyst: 75 years' perspective.@ HighBeam Research   (Site not responding. Last check: 2007-10-19)
Monsanto and sulphuric acid catalyst: 75 years' perspective.
The first 75 years of sulphuric acid catalyst production at Monsanto has seen the evolution of both technology and total quality customer service.
As part of the 75th anniversary celebration, Atis Vavere reviews the history of the Monsanto catalyst business with an emphasis on new technology, lots of secrecy, a bit of controversy, and the growth of a young chemical company.
highbeam.com /library/doc0.asp?DOCID=1G1:66497030&...   (216 words)

  
 Old Skool EP - Catalyst Recordings [acid house/out now] - Buzzlife Message Board
After almost a 2 year hiatus, Terry Mullan's Catalyst Recordings is back and ready to take over turntables worldwide.
This is a great example of dance floor acid house; punchy percussions with a quarky acid pattern that immediately jumps out of the grooves once it hits!
The track is complimented with shuffling hi-hat patterns, changing 808 and 909 percussion sequences, rhythmic background bleeps and bloops, and a DJ friendly intro and outro.
www.buzzlife.com /forums/showthread.php?t=53637   (359 words)

  
 mechanism for the acid catalysed hydrolysis of esters
Ethyl ethanoate is heated under reflux with a dilute acid such as dilute hydrochloric acid or dilute sulphuric acid.
Because the reaction is reversible, an equilibrium mixture is produced containing all four of the substances in the equation.
The dilute acid provides both the acid catalyst and the water.
www.chemguide.co.uk /physical/catalysis/hydrolyse.html   (933 words)

  
 UCSC Chemistry Dept., Faculty   (Site not responding. Last check: 2007-10-19)
Enantioselective reduction of aryl ketones using LiBH4 and TarB-X: a chiral Lewis acid.
Enantioselective reduction of prochiral ketones using LiBH4 and TarBcat-X: a chiral Lewis acid catalyst.
Boronic acid substituted viologen based optical sugar sensors: modulated quenching with viologen as a method for monosaccharide detection.
www.chemistry.ucsc.edu /recent_pubs.html   (3511 words)

  
 Articles - Organic reaction   (Site not responding. Last check: 2007-10-19)
either 2 ketones or carboxylic acid + ether
aldehyde + oxidizing agent (such as potassium permanganate, nitric acid, or chromium oxide)
Sulfuric acid + Sulfur Dioxide or, hot conc.
www.beadscenter.com /articles/Organic_reaction   (534 words)

  
 ipedia.com: Alkyne Article   (Site not responding. Last check: 2007-10-19)
alkyne + hydrogen gas + transition metal catalyst → alkane
alkyne + hydrogen gas + Lindlar catalyst → cis alkene
alkyne + water + mercury salt + acid catalyst → enol
www.ipedia.com /alkyne.html   (313 words)

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