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33-516: E2 , e2 , E02 , E.II , e or E-2 may refer to: Science and technology [ edit ] E2 reaction, a type of elimination reaction Honda E2 , one of the predecessors of Honda's ASIMO robot E2, a communications channel defined in the E-carrier standard G 2 (mathematics) (old name E2 or E 2 ), a group Biology and medicine [ edit ] Ubiquitin-conjugating enzyme ,

66-544: A 1915 German single-seat monoplane fighter aircraft Pfalz E.II , a German aircraft powered by the Oberursel U.I engine Taylor E-2 , a small, light and simple utility aircraft Embraer E-Jet E2 family , an updated version of the E-jet family Eastman E-2 Sea Rover , a 1920s seaplane Eurowings Europe (former IATA code: E2), an Austrian airline subsidiary of Lufthansa Kampuchea Airlines (former IATA code: E2),

99-530: A 2007 album by Eros Ramazzotti Television [ edit ] " E² ", an episode of Star Trek: Enterprise MTV e2 , a Canadian entertainment news program that airs on MTV Canada E2 (TV channel) , a Turkish TV channel e2 by SKY PerfecTV! , a satellite television service in Japan operated by SKY Perfect Transport [ edit ] Air [ edit ] Northrop Grumman E-2 Hawkeye , an American carrier-based AWACS aircraft Fokker E.II ,

132-691: A 3° haloalkane is reacts with an alkoxide, due to strong basic character of the alkoxide and unreactivity of 3° group towards S N 2, only alkene formation by E2 elimination is observed. Thus, elimination by E2 limits the scope of the Williamson ether synthesis (an S N 2 reaction) to essentially only 1° haloalkanes; 2° haloalkanes generally do not give synthetically useful yields, while 3° haloalkanes fail completely. With strong base, 3° haloalkanes give elimination by E2. With weak bases, mixtures of elimination and substitution products form by competing S N 1 and E1 pathways. The case of 2° haloalkanes

165-740: A Cambodian airline Rail [ edit ] E2 Series Shinkansen , a Japanese high-speed train EMC E2 , an early American passenger-train diesel locomotive LB&SCR E2 class , a class of 0-6-0T steam locomotives designed by Lawson Billington PRR E2 , an American PRR 4-4-2 locomotive CNW Class E-2 , a class of 4-6-2 steam locomotives built by the American Locomotive Company in 1923 Roads and footpaths [ edit ] E02 expressway (Sri Lanka) , in Sri Lanka E2 European long distance path ,

198-485: A human Y-chromosome DNA haplogroup Computing [ edit ] E2 (cipher) , a block cipher submitted to the AES competition by NTT Tungsten E2 , a business-class Palm OS-based handheld computer Motorola ROKR E2 , a smartphone Everything2 , a collaborative web-based community consisting of a database of interlinked user-submitted written material Arts and entertainment [ edit ] E (album) ,

231-767: A long-distance footpath that runs from Galway in Ireland to France's Mediterranean coast North–South Expressway Southern Route (E2), in Malaysia European route E002 , in Azerbaijan and Armenia E2 expressway (Philippines) , expressway route in the Philippines San'yō Expressway , Hiroshiwa-Iwakuni Road, Ogori Road and Yamaguchi-Ube Road, numbered as E2 in Japan Submarines [ edit ] HMS E2 , an E-class submarine of

264-455: A metal-carbene complex. In these reactions, it is the carbon adjacent to the metal that undergoes α-elimination.) In certain special cases, γ- and higher eliminations to form three-membered or larger rings is also possible in both organic and organometallic processes. For instance, certain Pt(II) complexes undergo γ- and δ-elimination to give metallocycles. More recently, γ-silyl elimination of

297-481: A model of the first series Class E2 in 1961. It was designed for the Trix Twin 3-rail system but could be converted to 2-rail using the optional 2-rail pick up included with the locomotive. Hornby produced the locomotive in its earliest form as an 00 gauge model. Production lasted from 1979 to 1985 in three distinct variants with four reference numbers. In 1985 the tooling was retired and after some alterations,

330-498: A one-step mechanism in which carbon-hydrogen and carbon-halogen bonds break to form a double bond ( C=C Pi bond ). The specifics of the reaction are as follows: An example of this type of reaction in scheme 1 is the reaction of isobutylbromide with potassium ethoxide in ethanol . The reaction products are isobutene , ethanol and potassium bromide . E1 is a model to explain a particular type of chemical elimination reaction. E1 stands for unimolecular elimination and has

363-558: A protein component of proteasome-mediated protein degradation E2 regulatory sequence , for the insulin gene Levuglandin E2 , an aldehyde Prostaglandin E2 , an abortifacient Prostaglandin E2 receptor , a human gene Iodine-deficiency (ICD-10 code: E02) Estradiol , an estrogen steroid hormone Dihydrolipoyl transacetylase , the second element of the multienzyme pyruvate dehydrogenase complex Acireductone dioxygenase (iron(II)-requiring) , an enzyme Haplogroup E2 (Y-DNA) ,

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396-420: A puzzle competition E-II Holdings, Inc., an investment holding company formerly owned by Meshulam Riklis , and later by Carl Icahn E2 grade, an assessment of difficulty in rock climbing See also [ edit ] E2c, earphones by Shure 2E (disambiguation) EII (disambiguation) [REDACTED] Topics referred to by the same term This disambiguation page lists articles associated with

429-773: A silylcyclobutyl tosylate has been used to prepare strained bicyclic systems. Many of the concepts and terminology related to elimination reactions were proposed by Christopher Kelk Ingold in the 1920s. LB%26SCR E2 class The London, Brighton and South Coast Railway (LB&SCR) E2 class was a class of 0-6-0 T steam locomotives designed by Lawson Billinton , intended for shunting and short distance goods trains . Ten examples were built between 1913 and 1916. Some of these tank engines were trialled on push-pull passenger trains in which they were proven to be unworthy due to their roughness at speed and inadequate coal bunker capacity. All were withdrawn from service and scrapped between 1961 and 1963. By 1910, many of

462-401: Is not a good leaving group, so eliminations with fluoride as the leaving group have slower rates than other halogens . There is a certain level of competition between the elimination reaction and nucleophilic substitution . More precisely, there are competitions between E2 and S N 2 and also between E1 and S N 1 . Generally, elimination is favored over substitution when For example, when

495-452: Is relatively complex. For strongly basic nucleophiles (p K aH > 11, e.g., hydroxide, alkoxide, acetylide), the result is generally elimination by E2, while weaker bases that are still good nucleophiles (e.g., acetate, azide, cyanide, iodide) will give primarily S N 2. Finally, weakly nucleophilic species (e.g., water, alcohols, carboxylic acids) will give a mixture of S N 1 and E1. For 1° haloalkanes with β-branching, E2 elimination

528-535: Is still generally preferred over S N 2 for strongly basic nucleophiles. Unhindered 1° haloalkanes favor S N 2 when the nucleophile is also unhindered. However, strongly basic and hindered nucleophiles favor E2. In general, with the exception of reactions in which E2 is impossible because β hydrogens are unavailable (e.g. methyl, allyl, and benzyl halides), clean S N 2 substitution is hard to achieve when strong bases are used, as alkene products arising from elimination are almost always observed to some degree. On

561-451: Is α-elimination. For a carbon center, the result of α-elimination is the formation of a carbene, which includes "stable carbenes" such as carbon monoxide or isocyanides . For instance, α-elimination the elements of HCl from chloroform (CHCl 3 ) in the presence of strong base is a classic approach for the generation of dichlorocarbene , :CCl 2 , as a reactive intermediate. On the other hand, formic acid undergoes α-elimination to afford

594-518: The Stroudley 0-6-0T E1 class locomotives were worn out or inadequate for the heavier duties required of them. D. E. Marsh intended to rebuild some examples with a larger boiler, but only one E1X rebuild had been completed by the time of his unexpected retirement in 1911. Marsh's successor, Billinton ousted the rebuilding of older engines policy and designed a new 0-6-0 tank engine design, commissioning Brighton works to build these engines to replace

627-497: The Weir pump and hot water injector for use on high-pressure steam. They had slotted frames, six small 4 ft 6 in (1.372 m) driving wheels, and a water tank capacity of 1,090 imp gal (5,000 L; 1,310 US gal). The first three engines were equipped with a reverser handle , whilst the last two were fitted with a screw-and-handle system . No. 100 was sent to work at Eastbourne , shunting trains in

660-724: The yard and pulling mid-day goods trains from there to the Ballast Hole on the Crumbles beach. This supplied shingle rocks for the LB&;SCR to use as track ballast , including the Midland Railway (MR) to balanced its coal lines. Nos. 101-104 were allocated to engine sheds based at Battersea , Brighton , and New Cross . Nos. 103 and 104 were trialled on local push-pull motor train service between London Bridge , Forest Hill and Crystal Palace , where each engine

693-675: The Royal Navy USS E-2 , an E-class submarine of the US Navy Other transport [ edit ] London Buses route E2 , England Other uses [ edit ] E-2 visa , a type of US visa E2, a postcode district in the E postcode area for east London, England Private E-2 , a pay grade for the rank of Private in the US Army E2 (nightclub) , a nightclub in Chicago, US Eternity II puzzle ,

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726-568: The electrification of the Brighton line in 1936, the class was used as replacements for the former LCDR T class at the Herne Hill marshalling yard, around Victoria station and at Dover harbour. During World War II , they also replaced the SR Z class at Hither Green marshalling yard . The class were trialled as dock shunters at Southampton in the 1950s, and were found to be suitable for

759-546: The ethyl (0.99) and isopropyl (1.72) analogues suggest competition between the two reaction modes. β-Elimination, with loss of electrofuge and nucleofuge on vicinal carbon atoms, is by far the most common type of elimination. The ability to form a stable product containing a C=C or C=X bond, as well as orbital alignment considerations, strongly favors β-elimination over other elimination processes. However, other types are known, generally for systems where β-elimination cannot occur. The next most common type of elimination reaction

792-504: The following specifications An example in scheme 2 is the reaction of tert-butylbromide with potassium ethoxide in ethanol. E1 eliminations happen with highly substituted alkyl halides for two main reasons. If S N 1 and E1 pathways are competing, the E1 pathway can be favored by increasing the heat. Specific features : The reaction rate is influenced by the reactivity of halogens , iodide and bromide being favored. Fluoride

825-416: The local engine crews preferred to use the older 0-6-2 T E3 tank engines, so No. 105 returned to Battersea. In 1921, with the LB&SCR increasing their wages, Billinton was instructed to carry out a series of time-and-motion studies covering likely economies in the railway department. As such, No. 109 was fitted with a service movement recorder to monitor its performance as a shunter. Following

858-505: The obsolete Stroudley E1 engines. By October 1912, Brighton Works began construction of the first batch of five E2s, with No. 100 delivered in June 1913. Nos. 101-104 followed on through to January 1914, taking approximately two months to build each engine. Additionally, they each cost £2,010 for Brighton works to build them. The E2 class included several features found on other LB&SCR classes including an I2 class boiler to accommodate

891-530: The onset of World War I , but were eventually delivered between June 1915 and October 1916, costing £2,217 each. The new E2s were allocated to London for use as station pilots, shunting empty coaches in and out of London Bridge and Victoria stations, but the increased demand of wartime saw them required to move wagons out to the northern railways. In May 1916, No. 105 was first assigned to Battersea and then to Three Bridges shed to assist in marshalling goods trains coming to and from north and west. However,

924-400: The other hand, clean E2 can be achieved by simply selecting a sterically hindered base (e.g., potassium tert -butoxide). Similarly, attempts to effect substitution by S N 1 almost always result in a product mixture contaminated by some E1 product (again, with the exception of cases where the lack of β hydrogens makes elimination impossible). In one study the kinetic isotope effect (KIE)

957-594: The same title formed as a letter–number combination. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=E2&oldid=1237276694 " Category : Letter–number combination disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Elimination reaction#E2 mechanism The E2 mechanism, where E2 stands for bimolecular elimination , involves

990-426: The stable products water and carbon monoxide under acidic conditions. α-Elimination may also occur on a metal center, one particularly common result of which is lowering of both the metal oxidation state and coordination number by 2 units in a process known as reductive elimination . (Confusingly, in organometallic terminology, the terms α-elimination and α-abstraction refer to processes that result in formation of

1023-555: The task. Six examples were retained for this purpose until their replacement by British Rail Class 07 diesel shunters in 1962. Withdrawal of the class took place between February 1961 and April 1963, and were all scrapped. In 1946, Reginald Payne used the later series of E2 locomotives as the basis for the character Thomas the Tank Engine in the second book of The Railway Series by the Reverend W. Awdry . Trix produced

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1056-456: Was determined for the gas phase reaction of several alkyl halides with the chlorate ion. In accordance with an E2 elimination the reaction with t-butyl chloride results in a KIE of 2.3. The methyl chloride reaction (only S N 2 possible) on the other hand has a KIE of 0.85 consistent with a S N 2 reaction because in this reaction type the C-H bonds tighten in the transition state. The KIE's for

1089-482: Was running in the middle of two sets of three coaches . However, they were proven to be unsuccessful due to their excessive oscillation, unsteadiness at speed and insufficient coal bunker capacity. Because of the inadequate water tank capacity on the first five engines, Billinton gave the next batch of five engines with extended side tanks , increasing up to 1,256 imp gal (5,710 L; 1,508 US gal). The second batch, Nos. 105-109, were delayed by

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