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Topic: Alkylation

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	Alkylation - Wikipedia, the free encyclopedia
		Alkylation is the transfer of an alkyl group from one molecule to another.
		In a standard oil refinery process, alkylation combines low-molecular-weight olefins (primarily a mixture of propylene and butylene) with isobutane in the presence of a catalyst, either sulfuric acid or hydrofluoric acid.
		Alkylate is a premium gasoline blending stock because it has exceptional antiknock properties and is clean burning.
	en.wikipedia.org /wiki/Alkylation (306 words)

	Alkylation -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-22)
		Alkylation is the transfer of an (Any of a series of univalent groups of the general formula CnH2n+1 derived from aliphatic hydrocarbons) alkyl group from one ((physics and chemistry) the simplest structural unit of an element or compound) molecule to another.
		The product is called alkylate and is composed of a mixture of high- (Any isomeric saturated hydrocarbon found in petroleum and used as a fuel and solvent) octane, branched-chain (British usage) paraffinic (An organic compound containing only carbon and hydrogen) hydrocarbons.
		Alkylate is a premium (A volatile flammable mixture of hydrocarbons (hexane and heptane and octane etc.) derived from petroleum; used mainly as a fuel in internal-combustion engines) gasoline blending stock because it has exceptional antiknock properties and is clean burning.
	www.absoluteastronomy.com /encyclopedia/a/al/alkylation.htm (283 words)

	Energy efficient alkylation process - Patent 4192825 (Site not responding. Last check: 2007-10-22)
		An alkylation process in accordance with claim 1 wherein said substantially HF free fraction passed to the propane concentration zone is a bottoms fraction taken from the fractionator.
		The alkylate is typically a mixture of isomers of heptane, octane, etc., with the exact composition depending upon the isoparaffin and olefin reactants used.
		Bottoms liquid from the separation column is recycled to alkylation with the overhead vapor from the separation column being condensed (to produce reflux for the separation column) and the yield portion is charged to the depropanizer to yield propane.
	www.freepatentsonline.com /4192825.html (5769 words)

	alkylation
		Alkylation reagents can be used alone to form esters, ethers and amides or they cam be used in conjunction with acylation or silylation reagents.
		Alkylation reagents are available in several configurations that enable the formation of a variety of esters.
		Used as the counter-ion extractive alkylation with methyl iodide as the alkylating reagent
	www.registech.com /gc/alkylation.html (503 words)

	DuPont Stratco \| Alkylation (Site not responding. Last check: 2007-10-22)
		The topic of mixing in a sulfuric acid alkylation unit encompasses 1) mixing of the isobutane and olefin feeds outside the reactor, 2) the method of feed injection, and 3) mixing intensity inside the reactor.
		The best quality alkylate is produced with the lowest acid consumption when: the "local" isobutane-to-olefin ratio in the mixing zone is maximized by premixing the olefin and isobutane feeds, the feed is rapidly dispersed into the acid/hydrocarbon emulsion, and intense mixing gives the emulsion a high interfacial area.
		of the primary factors affecting the reliability of an alkylation unit is the number and type of mechanical seals required in the reaction zone.
	www.stratco.dupont.com /alk/alkylation_03.html (1684 words)

	ThioSolv : Alkylation sulfuric acid alkylate gasoline component MTBE (Site not responding. Last check: 2007-10-22)
		Alkylate is the logical candidate to replace the octane barrels lost with the banning of MTBE.
		Although the alkylation reaction proceeds by way of ester formation, the concentration of ester in both the hydrocarbon effluent from the reactor system and in the spent acid should be zero, as ester in either stream represents a loss of both acid and potential alkylate.
		The heat of reaction is proportional to the amount of alkylate produced, so the manipulable variable in energy consumption to transfer heat is the compression ratio required in the iso vapor compressor to reject the heat.
	www.thiotech.com /alkylation.asp (804 words)

	Alkylation and Reforming (Site not responding. Last check: 2007-10-22)
		Alkylation produces isoparaffins from the reaction of light olefins produced by catalytic cracking.
		Both alkylation and reforming are catalytic processes, but the former occurs in the liquid phase with a sulfuric acid catalyst, while the latter is a hetergeneous reaction that takes place in a fixed bed of platinum or rhenium catalyst on an alumina support.
		With respect to alkylation and catalytic reforming, the reduction in the maximum allowable volume percent of aromatics in reformulated gasolines is particlularly relevant.
	www.unb.ca /che/che5134/AAR.htm (1195 words)

	[No title]
		The HF process differs from the H2SO4 alkylation in that the HF catalyst is managed in a closed-loop process, never leaving the unit for replacement or regeneration.
		Residuals were assigned to be "treating clay from alkylation" if they were assigned a residual identification code of "spent sorbent" and was generated from a process identified as a sulfuric acid or HF alkylation unit.
		Residuals were assigned to be "HF alkylation catalyst" if they were assigned a residual identification code of "liquid catalyst" and was generated from a process identified as an HF acid alkylation unit.
	www.epa.gov /epaoswer/hazwaste/id/studies/studyp.txt (17268 words)

	DuPont Stratco \| Alkylation (Site not responding. Last check: 2007-10-22)
		However, the owners and operators of HF alkylation units in most parts of the world are faced with public concern and regulatory attention regarding the safety of their units.
		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 debutanizer section of the HF unit is typically reboiled with a fired heater to reach a temperature level that thermally decomposes the organic fluorides in the alkylate.
	www.stratco.dupont.com /alk/alkylation_08.html (2689 words)

	World Intellectual Property Organization (Site not responding. Last check: 2007-10-22)
		Very often alkylate is obtained as a high boiling fraction in which the alkyl group attached to the aromatic nucleus varies in size from about C6 to about When cumene or ethylbenzene is the desired product, the present process produces acceptably little by-products such as xylenes.
		The alkylating agents which are useful in the process of this invention generally include any organic compound having at least one available alkylating group capable of reaction with the alkylatable aromatic compound.
		e., the alkylatable aromatic compound and the alkylating agent, are brought into contact with an alkylation catalyst in a suitable reaction zone such as, for example, in a flow reactor containing a fixed bed of the catalyst composition, under effective alkylation conditions.
	www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/83408.011108&ELEMENT_SET=DECL (2724 words)

	Sulfuric Acid Release Paper - Quest Consultants Inc. (Site not responding. Last check: 2007-10-22)
		Although the release and ignition of flammable fluids is a concern for the refinery operator, the release of toxic materials is often the event that poses the greatest threat to the general public.
		In 1990, a comparison of HF and sulfuric acid alkylation risks (4) estimated that a release of a sulfuric acid/alkylation hydrocarbon emulsion could result in 10 to 65 percent of the sulfuric acid becoming airborne.
		Alkylation equilibrium acid and hydrocarbon were charged from their respective storage tanks using nitrogen pressure to displace each liquid.
	www.questconsult.com /sulfuric.html (5391 words)

	Search Results for alkylation - Encyclopædia Britannica
		Alkylation is a general term for the introduction of an alkyl group into a compound and is more specifically known as methylation, ethylation, propylation, butylation, etc., depending upon the alkyl...
		Valuable greens and blues are derived by the process of sulfonation of diaminoanthraquinones to give dyes with the requisite degree of water solubility.
		After 1910 the demand for automotive fuel began to outstrip the market requirements for kerosene, and refiners were pressed to develop new technologies to increase gasoline yields.
	www.britannica.com /search?query=alkylation&submit=Find&source=MWTAB (266 words)

	Process for regenerating fluorosulfuric acid catalyst - Patent 4096199 (Site not responding. Last check: 2007-10-22)
		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.
		Although the broad concentration ranges are generally independent of the type of moderator used, the preferred or optimal range will vary depending on the structure of the moderator, the reaction temperature, the concentration and nature of the olefin in the feed, the amount of organic sludge present, and the olefin space velocity and the like.
		Sulfuric acid and the sludge formed during the alkylation process can be removed from the bottom of conversion/stripping zone 26 via line 48 and sent to sulfuric acid regeneration (not shown) for sludge removal and reconcentration, or it can be discarded.
	www.freepatentsonline.com /4096199.html (5911 words)

	Friedel-Crafts alkylation - Wikibooks
		Friedel-Crafts reaction, discovered by S. Friedel and D. Crafts in 1877, is either alkylation or acylation of aromatic compounds catalysed by a Lewis acid.
		Friedel-Crafts alkylation is an example of electrophilic substitution in aromatic compounds.
		Substituted aromatic compounds alkylate much more easily, so if you, for example, methylate benzene, the reaction will not stop on toluene and polysubstituted benzene will be produced.
	en.wikibooks.org /wiki/Friedel-Crafts_alkylation (396 words)

	Alkylation
		Alkylation combines low-molecular-weight olefins (primarily a mixture of propylene and butylene) with isobutene in the presence of a catalyst, either sulfuric acid or hydrofluoric acid.
		Alkylate is a premium blending stock because it has exceptional antiknock properties and is clean burning.
		) alkylation units, the feedstock (propylene, butylene, amylene, and fresh isobutane) enters the reactor and contacts the concentrated sulfuric acid catalyst (in concentrations of 85% to 95% for good operation and to minimize corrosion).
	www.setlaboratories.com /alkylation.htm (740 words)

	Tosco (Site not responding. Last check: 2007-10-22)
		The alkylation unit is one of the mainstays of the oil refining industry for the production of high-octane gasoline components.
		Sulfuric acid alkylation reactors are designed to produce intimate contact between the sulfuric acid (the reaction catalyst), the C3, C4 and C5 olefins and the isobutane (primary reactants) to convert the lighter unsaturated hydrocarbons to iso-paraffins that become high-octane motor gasoline components.
		The alkylation process will continue to be of great importance to the production of not only high octane gasoline components but also environmentally friendly low sulfur highly paraffinic motor gasoline.
	www.merichem.com /PROCESS/TechnicalArticles/Tosco.htm (2035 words)

	19931119 Use of hydrofluoric acid in the petroleum refining alkylation process. (Site not responding. Last check: 2007-10-22)
		The purpose of this bulletin is to alert field personnel to the potential safety and health risks posed by hydrofluoric acid (HF) used in HF alkylation units and to present the control measures implemented by industry to reduce workers' exposure, and pertinent OSHA requirements.
		Refineries use the acid in a manufacturing process called "alkylation," which is increasingly important in producing a high-quality gasoline.
		As with most refinery processes, the primary exposure control method used in HF alkylation units is the containment of all process substances within the unit equipment (i.e, vessels, piping, and pumps).
	www.osha-slc.gov /dts/hib/hib_data/hib19931119.html (923 words)

	Mechanisms of in Situ Activation for DNA-Targeting Antitumor Agents (Site not responding. Last check: 2007-10-22)
		The switch in the enantiomer alkylation selectivity of reversed versus extended analogues of the natural products coupled with the different but identical alkylation selectivities of enantiomeric sandwiched analogues confirmed that it is the noncovalent binding selectivity and not the alkylation subunit or alkylation site that is controlling the alkylation selectivity.
		The second alkylating center of mitomycin is the iminium ion formed from the elimination of the C10 carbamate (Figure 6).
		A second contribution to the selectivity of the cross-link stems from the preferred orientation of the covalent monoadduct in the DNA minor groove, in which it is poised to form the cross-link without significant structural reorganization of the DNA.
	pubs.acs.org /cgi-bin/sample.cgi/chreay/2002/102/i07/html/cr010046q.html (9341 words)

	Synthesis and alkylation of some [1,2,4]triazolo[4,3-b]tetrazines (Site not responding. Last check: 2007-10-22)
		In each case the alkylation of the heterocycles proceeded readily accompanied by the change of the colour of the reaction mixture to purple.
		To prove the formation of the alkyl-triazolotetrazinium salts and to obtain information on the selectivity of the alkylation, the triazolotetrazines (3,6) were reacted with triethyloxonium tetrafluoroborate in deuterated acetonitrile at ambient temperature and the reaction was monitored by NMR spectroscopy.
		Detectable alkylation of 3 occurred only on the pyrazole ring yielding 9, the structure of which was unambiguously established by DNOE experiments.
	www.arkat-usa.org /ark/journal/2000/I03_Jones/GJ-012E/033.asp (2038 words)

	Theoretical Insights into Alkylation Catalysis over Polyoxometalates (Site not responding. Last check: 2007-10-22)
		The relative rate of hydride transfer compared to the alkylation and isomerization steps must be considered in the rational design of effective catalytic materials.
		The reaction energetics of alkene adsorption and oligomerization, alkylation, and hydride transfer steps are reported to provide molecular scale understanding of the pathways to deactivation due to the buildup of heavy hydrocarbons.
		The prospects of developing a solid acid catalyst for the alkylation of isobutane and n-butene will be discussed based on the reaction energetics determined for heteropolyacid catalysts.
	aiche.confex.com /aiche/2005/techprogram/P17279.HTM (415 words)

	The Paterson Group - Publications
		t-Butylation of aldehydes and ketones by the Friedel-Crafts alkylation of trimethylsilyl enol ethers.
		α-Alkylation of ketones, esters, and lactones: zinc bromide catalysed alkylation of O-silylated enolates, a synthesis of (±)-ar-turmerone.
		γ-Alkylation of unsaturated ketones and esters: zinc bromide catalysed alkylation of O-silylated dienolates.
	www-paterson.ch.cam.ac.uk /pubs.html (3652 words)

	The Foxboro Company \| Strategic Meas. Ops \| NMR \| Application Solutions \| Alkylation
		The alkylation unit control system provides composition measurement and control solutions to reduce or eliminate problems characteristic of sulfuric acid alkylation unit operation.
		In April 1997, the first on-line process NMR analyzer for sulfuric acid alkylation control was installed at a Los Angeles area refinery.
		All other analysis methods currently being applied to alkylation acid are performed in the settler or in the lab (titration) where the acid/hydrocarbon emulsion has been broken.
	www.process-nmr.com /fox-app/alkltn.htm (1284 words)

	Leona Samson, Adjunct Professor of Toxicology, Department of Genetics and Complex Diseases, Harvard School of Public ... (Site not responding. Last check: 2007-10-22)
		Alkylating agents represent an abundant class of chemical DNA damaging agent in our environment and they are toxic, mutagenic, teratogenic and carcinogenic.
		The repair of DNA alkylation damage provides tremendous protection against the toxic effects of these agents and our aim is to understand the biology, the biochemistry, and the genetics of numerous DNA repair pathways that act upon DNA alkylation damage.
		Specifically, we have: (i) produced transgenic and knock-out mice with altered DNA repair capabilities and are now measuring their susceptibility to alkylation toxicity; and (ii) transferred DNA alkylation repair genes to bone marrow cells to determine whether such gene therapy could confer a useful level of extra resistance in the bone marrow of chemotherapy patients.
	www.hsph.harvard.edu /facres/smsn.html (974 words)

	Environmental Defense - Alkylation and Reforming
		Alkylation and reforming are refinery processes which produce components of gasoline that increase octane, which controls engine "knocking." Alkylation converts lighter petroleum hydrocarbons into heavier hydrocarbons, making alkylation essentially the opposite of cracking.
		Alkylation uses either sulfuric acid or hydrofluoric acid as a catalyst to transform propylene, butylene and/or isobutane into alkylation products, or alkylate.
		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.
	www.environmentaldefense.org /article.cfm?ContentID=1571 (441 words)

	New Strategies in Organic Catalysis: The First Enantioselective Organocatalytic Friedel-Crafts Alkylation (Site not responding. Last check: 2007-10-22)
		A further illustration of the utility of this organocatalytic Friedel-Crafts alkylation is presented in the reaction of N-methyl pyrrole with excess crotonaldehyde (eq 4).
		and (ii) all of the alkylations described herein were performed under an aerobic atmosphere, using wet solvents and an inexpensive bench-stable catalyst.
		In summary, we have further established LUMO-lowering organocatalysis as a broadly useful concept for asymmetric synthesis in the context of the Friedel-Crafts alkylation.
	pubs.acs.org /cgi-bin/jcen?jacsat/123/i18/html/ja015717g.html (1246 words)

	3-Methyladenine DNA Glycosylase-deficient Aag Null Mice Display Unexpected Bone Marrow Alkylation Resistance -- Roth ...
		BM cells to a number of alkylating agents (12).
		Ex vivo alkylation sensitivity of BM cells from Aag null and wild-type mice.
		In vivo alkylation sensitivity of BM cells from Aag null and wild-type mice.
	cancerres.aacrjournals.org /cgi/content/full/62/3/656 (3885 words)

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