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|Section2= |Section3= |Section7= |Section8= }} Methylcyclopentadienyl manganese tricarbonyl (MMT or MCMT) is an organomanganese compound with the formula (CH3C5H4)Mn(CO)3. Marketed as a supplement to the gasoline additive tetraethyllead to increase a fuel's octane rating, MMT was later used in unleaded gasoline. Following the implementation of the Clean Air Act (United States) (CAA) in 1970, MMT continued to be used alongside TEL in the US during the phase-out of leaded gasoline (prior to TEL being finally banned from US gasoline in 1995) and was also used in unleaded gasoline until 1977. Ethyl Corporation obtained a waiver from EPA in 1995. The waiver allows the use of MMT in US unleaded gasoline (not including reformulated gasoline) at a treat rate equivalent to 8.3 mg Mn/l.〔60 FR 36414 - Fuels and Fuel Additives; Grant of Waiver Application.()〕 MMT has been used in Bulgaria, France, Argentina and in Canadian gasoline since 1976 at a concentration up to 18 mg Mn/l (though the importation and interprovincial trade of gasoline containing MMT was restricted briefly during the period 1997-1998)〔''The Globe and Mail'' "Threat of NAFTA Case Kills Canada's MMT Ban: Challenge over gasoline additive could have cost Ottawa millions". July 20, 1998.〕〔MMT, A Risk Management Masquerade.()〕 and was introduced into Australia in 2000. It is sold under the tradename HiTEC® 3000.〔Frumkin, Howard and Solomon, Gena; "Manganese in the US Gas Supply" American Journal of Industrial Medicine, 31: 107-115 (1997)〕 It was also marketed as Ecotane by T2 Labs.〔(【引用サイトリンク】title=Report: Owners of Jacksonville's T2 Lab never knew risks of deadly explosion )〕 ==History of use in the U.S.== Tetraethyllead (TEL) has been, and still is on a limited scale, used as an additive to increase the octane rating of gasoline. In the U.S., TEL was manufactured and marketed by the Ethyl Corporation, a joint venture between General Motors and DuPont. When the United States Environmental Protection Agency (EPA) ordered the phasing out of leaded gasoline in 1973, new fuel additives were sought. Developed as an octane improver, though initially marketed in 1958 as a smoke suppressant for gas turbines, MMT was used in 1974 as an additive in unleaded gasoline. In 1977, the U.S. Congress amended the CAA to require advance approval by the EPA for the continued use of fuel additives such as MMT, ethanol, ETBE, etc.〔42 USC § 7545 - Regulation of fuels.()〕 The new CAA amendment required a “waiver” to allow use of fuel additives made of any elements other than carbon, hydrogen, oxygen (within certain limits) and nitrogen.〔Definition of Substantially Similar.(www.epa.gov/otaq/regs/fuels/additive/jan91.pdf )(www.epa.gov/otaq/regs/fuels/additive/july81.pdf )〕 To obtain a waiver, the applicant has to demonstrate that the fuel additive will not lead to a failure of vehicle emission control systems. Ethyl Corporation applied for a waiver in both 1978 and 1981 and in both cases the applications were denied because of stated concerns that MMT might damage catalytic converters and increase hydrocarbon emissions. In 1988, Ethyl began a new series of discussions with EPA to determine a program for developing the necessary data to support a waiver application. In 1990, Ethyl filed its third waiver application prompting an extensive four-year review process. In 1993, the U.S. EPA determined that use of MMT at 8.3 mg Mn/l would not cause, or contribute to, vehicle emission control system failures.〔58 Fed. Reg. 64,761 (December 9, 1993)〕 EPA ultimately denied the waiver request in 1994, however, due to uncertainty whether manganese emissions from use of MMT might present a potential public health concern.〔Fuels and Fuel Additives;Waiver Decision/Circuit Court Remand.()〕 As a result of this ruling, Ethyl Corporation began a legal battle with the EPA claiming that EPA had exceeded its authority by denying the waiver on these grounds. This was upheld by the US Court of Appeals〔Waiver Ruling.()〕 and EPA subsequently granted a waiver which allows the use of MMT in US unleaded gasoline (not including reformulated gasoline) at a treat rate equivalent to 8.3 mg Mn/l. Implementation of this less-toxic alternative to TEL has been controversial. Opposition from automobile manufacturers and some areas of the scientific community has reportedly prompted oil companies to voluntarily stop the use of MMT in some of their countries of operation.〔Marco Di Girolamo, Maura Brianti, Massimo Conte, Mario Marchionna "Octane Enhancers" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. 〕 MMT is currently manufactured in the U.S. by the Afton Chemical Corporation, a subsidiary of Newmarket Corporation.〔Afton Chemical Ltd.()〕 It is also produced and marketed as "Cestoburn" by Cestoil Chemical Inc. in Canada. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Methylcyclopentadienyl manganese tricarbonyl」の詳細全文を読む スポンサード リンク
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