(Methylcyclopentadiényl) Manganese tricarbonyl – Wikipedia

(Methylcyclopentadiényl) Manganese tricarbonyl
Structure of (methylcyclopentadiényl) Manganese tricarbonyle
Identification
Synonyms	after-content-x4 MECPMN (CO) 3
N O CAS	12108-13-3
N O Echa	100,031,957
N O THIS	235-166-5
N O RTECS	OP1450000
Pubchem	25511
SMILES
Inches	Std. Inchi: 3D view Inchi = 1S/C6H7.3CO.MN/C1-6-4-2-3-5-6; 3*1-2;/h2-5h, 1h3 ;;;//Q-1 ;;;; Std. InChIKey : ISYSGJCJSRBFZSZ-UHFFFAOYSA-N
Appearance	dark orange liquid with a pleasant smell
Chemicals
Formula	C 9 H 7 Too much 3 C 9 H 7 Too much 3 −
Molar mass [ first ]	218.088 1 ± 0.008 6 g/mol C 49.57%, H 3.24%, MN 25.19%, by 22.01%,
Physical properties
T° fusion	2.2 °C [ 2 ]
T° boiling	232.8 °C [ 2 ]
Solubility	ten mg · l -first [ 2 ] To 20 °C
Volumic mass	1.39 g · cm -3 [ 2 ]
T° d’auto-inflammation	257 °C [ 2 ]
Flash point	96 °C [ 2 ]
Saturating steam pressure	6.3 He [ 2 ]
Precautions
SGH [ 2 ]
Danger H301 , H310 , H330 , H410 , P260 , P262 , P264 , P270 , P271 , P280 , P284 And P301+P310 H301 : Toxic in case of ingestion H310 : Mortal by skin contact H330 : Mortal by inhalation H410 : Very toxic to aquatic organisms, leads to long -term effects P260 : Do not breathe dust/smoke/gas/fogs/vapors/aerosols. P262 : Avoid any contact with eyes, skin or clothes. P264 : Wash … carefully after handling. P270 : Do not eat, drink or smoke by manipulating this product. P271 : Use only outdoors or in a well -ventilated place. P280 : Wear protective gloves/protective clothing/eye/face protective equipment. P284 : Wear respiratory protective equipment. P301+P310 : In case of ingestion: Immediately call an anti -poison center or a doctor.
Transport [ 2 ]
Code Kemler : 66 : very toxic material UN number: 3281 : Metals-carbonyles, n.s.a. Class: 6.1 Code de classification : T3 : Toxic materials without subsidiary risk: Organometallic; Label : 6.1 : Toxic materials Packaging : Packaging group I : very dangerous materials; ; Code Kemler : 60 : toxic material or with a minor degree of toxicity UN number: 3281 : Metals-carbonyles, n.s.a. Class: 6.1 Code de classification : T3 : Toxic materials without subsidiary risk: Organometallic; Label : 6.1 : Toxic materials Packaging : Packaging group II / III : moderately/weakly dangerous materials.
IS units and CNTP , unless otherwise stated.
modifier

The (methylcyclopentadiényl) Manganese tricarbonyl is an organomietal compound (metal carbonyl) of chemical formula ( the ⁵ -CH ₃ C ₅ H ₄ ) Mn (CO) ₃ whose geometry is said to be “half-sandwich” or “in piano stool”. It is a cellular toxic which releases by degrading compounds which contain manganese, which is a metal becoming neurotoxic beyond the doses which make it an oligoelement.

Photudegradable and thermodegradable, this product invented and put on the market in the 1950s by the company Ethyl Corporation (which is also the source of tetraethyl lead) is mainly used as an additive of fuels (antidostonant) since the 1970s, Stronger concentrations when he replaced lead in unleaded petrol, due to the strong toxicity of the latter. Its combustion in car engines contributes to pollution of the atmosphere in manganese compounds.

It is a dark orange liquid with a pleasant smell.

The molecule consists of an anion cyclic aromatic methylcyclopentadiényle C ₅ H ₄ CH _{3 ⁻}, a MN manganese atom, and three carbonyl co -co.

This molecule was invented by an petrochemical group (Ethyl Corporation), based in Richmond in the 1950s to increase the degree of octane of fuel ^{[ 3 ]} . Doubts as to its safety for health and the environment were already issued in the early 1970s ^{[ 4 ]} .

MMT was only authorized in gasoline in 1977 in the United States. In 1995, Ethyl Corporation received a dispense of the American environmental protection agency (U.S. EPA) authorizing its use in unleaded petrol in the United States (excluding reformulated petrol) at a rate equivalent to 8.3 MG MN/L (manganese by liter) ^{[ 5 ]} .

In 1979 during an oil crisis, the EPA, at the request of the government and the industry authorized the addition of MMT in unleaded petrol for a few months and while it was planned to prohibit Lead in petrol at the end of 1995 ^{[ 3 ]}

According to Ethyl Corporation more than 70 million pounds (Pounds) of MMT were sold in the United States from 1976 to 1998 ^{[ 3 ]} .

It has been used historically (since the 1970s ^{[ 6 ]} ), in addition to the lead tetraethyle (CH ₃ CH ₂ ) ₄ Pb _{, comme additif pour carburant pour en accroître l’indice d’octane en réduisant leur sensibilité à l’auto-allumage — et donc leur tendance à produire des cliquetis^[7].}

This product was first used in doses corresponding in 1975 to around 0.025 g manganese/gal for fuel oil and 0.08 to 0.5 g /GAL for turbine fuels ^{[ 7 ]} . It was also initially used at low doses in seafood and then in much larger doses during the introduction to the unleaded petrol market (which he replaced, with benzene or other compounds) ; The dosage then increased to 0.125 grams of manganese/gal, so as to avoid rattling while protecting the engine from other manganese effects ^{[ 7 ]} .

The impact of the use of MMT on humans and the environment is a function:

• MMT in its original, unaltered chemical form; and or
• manganese from its combustion with essence and emitted by exhaust pots.

MMT in its original form (as a chemical compound before combustion) [ modifier | Modifier and code ]

The (methylcyclopentadiényl) Manganese Tricarbonyl (MMT) concentrated (before combustion) is a source of cell toxicity ^{[ 8 ]} . In particular, it affects the functioning of mitochondria and consequently cell breathing ^{[ 9 ]} .

Pulmonary toxicity is observed in vitro and in the laboratory in rats, mouse and hamster ^{[ ten ]} , without causing the same pulmonary toxicity as Bléomycin or Cyclophosphamide in laboratory mice and laboratory rat ^{[ 11 ]}

People exposed chronically at high doses of MMT are likely to develop an irreversible neurodegenerative disease (mangalism).

It should be noted that the general public is not or very little exposed to MMT in its original form, before it is burned during the combustion of gasoline. As the American Environment Protection Agency (US EPA) explains in their MMT risk analysis, “exposure to MMT, apart from professional or accidental contact cases, was not considered as posing a significant risk for the population ” ^{[ twelfth ]} .

Manganese from the combustion of MMT [ modifier | Modifier and code ]

During combustion, methylcyclopentadiényl Manganese Tricerna (MMT) by deteriorating releases in the environment of manganese particles via the exhaust of the vehicle. Manganese is neurotoxic beyond the doses which make it an oligoelement and can, in individuals who would be more exposed, or more vulnerable, cause manganese intoxication. According to tests published in 1975 by manufacturers producing fuel additives, the amount of manganese emitted in the air by an average car (on test bench) was comparable to the quantity of particulate lead emitted by an engine powered by seafood. And the size of manganese particles (mainly MN ₃ O ₄ ) emitted by the exhaust was 0.2 to 0.4 micron; 98.7% of this manganese being issued in inorganic form according to the Ethyl Corporation Research Laboratories ^{[ 7 ]} . According to an estimate made in 1975 by these same producers, if all the gasoline was leadless (with 0.1 g manganese by gallon in the form of MMT) US urban air should not contain more than 0.02 to 0.2 µg/m ³ manganese, with an average value of 0.05 µg/m ³ and a tiny concentration of organic manganese.

There does not seem to be data published on what becomes the product issued in the night environment. Lynam in 1998 adds that MMT has significantly reduced Nox emissions ^{[ 6 ]} . And according to him only less than 15% of manganese from the combustion of the MMT is emitted in the air from the exhaust pipe (mainly in the fraction of PM 2.5 in the form of manganese phosphate and less manganese and a small proportion of manganese oxide.

Studies done in Toronto in the 1990s concluded that a low exposure of the general population (0.008 microgram/m ³ air-median), is much less than the limits set by EPA in the United States. Air analyzes made in Toronto have also shown low persistence in the air (ambient levels in the air in Toronto comparable to levels measured in areas where MMT is not used ^{[ 6 ]} ).

Close to the most circulating tracks, exposure increases, however, and in certain regions this manganese is added to that issued by coal power plants and metallurgical factories. A study sought in Montreal to assess air contents in MMT, breathable manganese (MNR) and total manganese (MNT) in 5 micro-environment a priori more exposed to MMT: a gas station, a parking lot Underground, the city center, an area close to a highway and another near an oil refinery. The average MNR, MNT and MMT rates were 0.036 microgram/m respectively ³ , 0,103 microgramme/m ³ and 0.005 microgram/m ³ . MNR/MNT ratios varied from 25% to 43% (35% on average), while the MMT/MNT average ratio was 5%. MNR level was 0.053 microgram/m ³ Near the highway, reaching the reference threshold of the EPA (which was 0.05 microgram/m ³ ). This study estimated that the daily environmental exposure of the general public was in the 1990s of 0.010 microgram kg ⁻¹ j ⁻¹ For the “inhalation” fraction and that this contribution to total exposure (via air, water, skin and food) remains low. Even near a highway ^{[ 5 ]} .

In 2005, when there was always little about its potential health and environmental effects ^{[ 3 ]} , a study estimated the share of automotive pollution in MN and MMT deposits compared to the volume of traffic on sites close to a highway in the Grand Toronto, where the MMT is still used. Manganese contributions have been estimated according to average traffic (Annual Average Daily Traffic or Aadt), vehicle density, their fuel consumption, the distance they roam and the MN (MG L-1) concentration of the essence ^{[ 13 ]} . Multiple linear regression analysis was used to assess the contributions for the period 2002-2010. The results were 99% predictive of the rates measured for two sites; “The 15% emissions of emissions by exhaust pots for an essence containing 10 mg of MN/L, represented 1290.03 g/year for site n ° 1 and 555.94 g/year for site 2” ^{[ 13 ]} . Traffic therefore adds 5.73 and 2.47 mg /g of MN each year respectively for these 2 sites, contributions which according to the authors can still be considered negligible compared to the natural abundance of the MN in the soil ^{[ 13 ]} .
If the circulation does not increase and on the basis of this modeling, it would take more than 95 years and over 256 years to double on these two sites the floor content in MN on these two sites ^{[ 13 ]} .

However, there does not seem to be a study which compared the bioavailability of manganese issued by the exhaust pots to the one in the soils, largely complexed in humus or clay.

Global risk assessment [ modifier | Modifier and code ]

Methylcyclopentadiényl manganese tricarbonyl (MMT) is quickly degraded at high temperature (in the engine of a car in particular). It is also quickly degraded by light (photodégradation at a wavelength between 340 and 440 nanometers) in the presence of oxygen with different intermediate molecules and degradation by-products.
It should therefore be degraded in a few seconds to a few minutes in full sun ^{[ 7 ]} , and not pose a public health problem as such (but the resulting manganese remains neurotoxic).

It also does not appear that humans and the environment undergo significant exposure to manganese compounds (manganese phosphate, manganese sulfate and manganese tetraoxide) from the combustion of MMT. In a risk study on the health effects of manganese compounds from the combustion of MMT, the Federal Health Ministry of Canada concluded that exposure to these compounds was not a significant risk for the population ^{[ 14 ]} . In 2013, a health assessment report was developed by Arcadis Consulting and verified by a group of independent experts according to the methodology provided by the European Commission in compliance with the criteria defined by the European Directive “Quality of fuel”. THE Reporting conclusions are as follows: “For MMT and products from its transformation, when the MMT is used as Additive for fuel, no major problem has been identified for human health and the environment, that the Exposure either to MMT or products from its transformation (combustion) when using up to 18 mg mn/l. Depending on local needs and technology for controlling the available vehicle emissions, use of MMTs whose rate is between 8.3 mg mn/l and 18 mg mn/l is scientifically justified and is likely to produce effects beneficial for the economy and the environment without producing negative effects ” ^{[ 15 ]} .

Related articles [ modifier | Modifier and code ]

External link [ modifier | Modifier and code ]

Bibliography [ modifier | Modifier and code ]

• Autissier, N., Dumas, P., Brosseau, J., & Loireau, A. (1977). Action of the Manganese Methylcyclopentadien Tricarbonyl (MMT) on mitochondria I. MMT effects, in vitro, on oxidative phosphorylation of hepatic mitochondria of rats. Toxicology, 7 (1), 115-122 ( résumé ).
• Davis, J. M. (1998). Methylcyclopentadienyl manganese tricarbonyl: health risk uncertainties and research directions . Environmental health perspectives, 106(Suppl 1), 191.
• Haton, P. J. J. . Potentiating effects of oxygen in lungs damaged by methylcyclopentadienyl manganese tricarbonyl, cadmium chloride, oleic acid, and antitumor drugs . Toxicology and applied pharmacology, 67(1), 55-69 ( résumé )
• Kitazawa, M., Wagner, J. R., Kirby, M. L., Anantharam, V., & Kanthasamy, A. G. (2002) Oxidative stress and mitochondrial-mediated apoptosis in dopaminergic cells exposed to methylcyclopentadienyl manganese tricarbonyl . Journal of Pharmacology and Experimental Therapeutics, 302(1), 26-35.
• Ressler, T., Wong, J., Roos, J., & Smith, I. L. (2000). Quantitative speciation of Mn-bearing particulates emitted from autos burning (methylcyclopentadienyl) manganese tricarbonyl-added gasolines using XANES spectroscopy . Environmental science & technology, 34(6), 950-958.
• HOT loud, G. l., M., M. E. E., M., Merciful, DBelging, D. g., M. G., M. (Kappron, M. (1975) Methylcyclopentadienyl manganese tricarbonyl as an antiknock : Composition and fate of manganese exhaust products . Journal of the Air Pollution Control Association, 25(8), 858-859