An introduction to the applications of Methylcyclopentadienyl Manganese Tricarbonyl
To support the rapid development of automotive industry, the oil industry is required to provide newer, next generation petroleum products. Therefore, the primary objective of refining industry is to supply gasoline meeting the market demand. The technical options in raising the Octane Number of gasoline are:
●Upgrade the refining technology: FCC, Catalytic Reforming, Alkylation, Isomerization etc
●Adding high octane blending components: Heavy Aromatics, MTBE, Ethanol fuels etc
●The use of antiknock compounds
value of Ethanol gasoline is low, poor power output and high oil consumption, Ethanol gasoline is therefore not widely accepted. On the other hand, due to the tightness in global food supply, it is not possible to use grains for ethanol production. The use of mixed Aromatics to increase Octane would lead environmental pollution and harmful to human health.
There are technical deficiency or cost disadvantage if solely rely on technology upgrade or high octane blending component. It has been proven in practical applications that the use of antiknock compounds is a cost-effective mean. In most of the gasoline production in the world, the use of antiknock compound plays a complementary role in raising the octane of gasoline.
Tetra Ethyl Lead (TEL) was the most cost effective antiknock compound, it has been widely used in the world. TEL has fruity odor, an extremely toxic oily substance. It could enter human body through inhalation, ingestion or skin contact, and Lead will remain in human body. Therefore, Leaded gasoline is very harmful to the environment and human health.
With the increase of vehicle population and the desire to protect the environment and pollution control, many countries in the world prohibited the sales of Leaded gasoline, and legislated strict emissions control standards and environmental protection laws. Unleaded gasoline is now widely use in most countries and regions in the world.
二、The introduction and development of MMT
As Lead antiknock compound is highly toxic, research efforts were focused on identifying suitable Lead replacement products. For many years, both metallic and non-metallic antiknock compounds have been evaluated. Among the metallic compounds, Iron-based antiknock compound is also capable in boosting octane of gasoline, there are countries and regions in the world using Ferrocene to blend gasoline. However, its prolonged usage would lead to engine wear and spark plug fouling.
In Xiamen area in China, the use of Iron-based gasoline resulted in damage to about 60 vehicles. Therefore, there are countries in the world prohibit the use of Iron-based antiknock compound, China included.
Commercially, it is proven that Manganese-based antiknock compound is superior in quality and remains the most widely used antiknock compound in the world
Methylcyclopentadienyl Manganese Tricarbonyl was developed by Ethyl Corp in 1953. It was first used as a supplementary product for gasoline.
From 1974 to 1977, MMT was approved for use in Unleaded gasoline, unfortunately, with the issuance of ‘Clean Air Act’ which stipulated that ‘Waiver Approval’ has to be obtained from US EPA prior to the sales of all gasoline additives.
The determination to demonstrate that MMT is ‘environmentally friendly’ is the basis to obtain the ‘waiver approval’ for MMT from US EPA, Ethyl Corp conducted a series of MMT test program, under EPA supervision and participation from automotive manufacturers to jointly design the test protocol. This protocol clearly registered the impact of MMT on vehicle tailpipe emissions.
In the history of combustion additive, MMT undergone most severe test programs, including 126 vehicle field trial and thousands of ‘extra’ tests not requested by EPA. EPA claimed that ‘ this is the most widely test program conducted by a waiver applicant’. The test results satisfied the standards set by the government, including the proof that MMT would not harm public health, even at the lowest risk level.
The test also proved that MMT would not harm the vehicle, including the emission and control systems. The MMT ‘waiver approval’ granted by EPA has path the way for MMT usage in Unleaded gasoline, this has generated a very significant impact on global basis in producing environmentally friendly and fuel efficient gasoline.
In 1977, MMT was first introduced into Canada for Unleaded gasoline production, and continue to be used since for the last 30 years. On July 20th, 1998, The Canadian government issued a statement that ‘At this junture, there is no scientific evidence to prove that MMT affects the functions of vehicle OBD system, also there is no scientific evidence to alter the statement of Health Canada made in 1994 that MMT would not harm the public health’.
MMT has been used as a supplementary additive in USA prior to the phase out of Leaded Gasoline, that is, to use in combination with TEL to produce Leaded Gasoline. In October 1995, US EPA approved the use of MMT in Unleaded gasoline. Currently, MMT is widely used in Argentina, Australia, Bulgaria, Canada, Russia and New Zealand.
In 1987, the Australia Health Department issued a statement that under heavy traffic condition, the increase in Manganese level in air with the use of MMT gasoline, would be 3-4 folds below the ‘poisons level’, hence MMT would not harm the human health.
In December 28, 1999, China issue the National Standard on ‘ Unleaded gasoline for vehicles GB 17930-1999’ which approved the use of MMT in gasoline. One of the State-owned enterprises, CNPC instructed all subsidiary refineries to mandate the use of MMT. Similarly, another state enterprise, Sinopec in the document 2001-23 also instructed subsidiary refineries to use MMT.
MMT was promoted by Ethyl Corp since 1996, it has been widely accepted for use by most of the refineries in China. The quantity of import has increased steadily. In 2010, the demand for both imported and domestic MMT was around 3000 MT.
An introduction to the applications of
Methylcyclopentadienyl Manganese Tricarbonyl
●Methylcyclopentadienyl Manganese Tricarbonyl (MMT)
●METHYLCYCLOPENTADIENYLMANGANESETRICARBONYL
●Molecular Formula C9H7MnO3
●Molecular Weight 218.0887
●CAS Number 12108-13-3
●Related Classifications
Organometallics; Catalysis and Inorganic
Chemistry; Chemical Synthesis; Manganese
●Molecular Structure
MMT Safety Data Sheet
Physical and Chemical properties of MMT
A Photo of MMT Sample
The mechanism of MMT antiknock property
MMT reaction mechanism is similar to TEL, under combusting conditions, MMT is decomposed
to form active Manganese Oxide particles. Due to surface-active action of the particles, there remove
the peroxides already formed in the engine combustion chambers, leading to a reduction of peroxides
concentration at the front of the flame, also selectively terminate the free-radical chain reaction, thereby
inhibit the auto-ignition and slow down the velocity of energy release, resulted in an increase in the
antiknock property of gasoline fuel.
The susceptibility of MMT to various hydrocarbons:
●Paraffins> Olefins> Aromatics
●Low Octane No fuel >High Octane No fuel
●Research Method > Motor Method
●Initial increment is larger than secondary increment
The benefits of MMT:
●At dosage of 1: 10,000, the Manganese content in gasoline is 18 mg/l, MMT boosts octane by 2 to
3 number
●Excellent combustibility, improves engine power and fuel economy
Test Result (Chins National Automobile Quality Inspection Centre)
The result of test
(National automobile quality supervision and inspection center)
●No side effect. It has no effectonother P&C properties of gasoline.Compatible with MTBE,Ethanol and other blending components
●Good storage stability.No phase separation and no change in quality after
●Low toxicity and would not pollute the environment。
The MMT susceptibility by world region
The RON increase in RON 86-88 base gasoline
The RON increase in RON 92-96 base gasoline
The summary of MMT application in refinery
* Light FCC gasoline, when RON of base fuel is around 84-85, and MMT is used at 18 mg/l Mn,
RON boost is around 2.5-3.0. Under normal situation, MMT alone could be added to FCC gasoline to
achieve RON 87 specification.
* Heavy FCC gasoline, usual RON of base fuel is around 91. With the use of MMT at 18 mg/l Mn to
achieve RON 93 gasoline specification.
The economic comparison of MMT and MTBE:
Assuming the price of MTBE is higher than finished gasoline by Euro 110/ MT, price of 62% MMT is
Euro 12000/ MT, price of RON 87 finished gasoline is Euro 520 /MT
* Cost calculation based on same blending effect
Cost of MTBE is 8% x 110 = Euro 8.8
Cost of MMT is 160 ppm x (12000-520) = Euro 1.8
* The conclusion is that when MMT is used to substitute MTBE in gasoline blending formulation, the
cost saving is Euro 7 per MT of gasoline. For a refinery with an annual gasoline production of 200,000
MT, the total cost saving is Euro 1.4 million per annum.
The conversion table for MMT dosage in gasoline
The conversion table for MMT dosage in gasoline
MMT is packed in 200 L steel drum, 1 M , 5 M , 10 M steel container
● MMT is to be stored in cool place with good ventilation and far away from ignition source. The valves of container should be shut when not in use.
As MMT is light sensitive, amber glass bottle or metal container are recommended for use when
collecting MMT sample, and to avoid light when conducting MMT analysis in the laboratory.
MMT not exposed to light MMT exposed to strong light for 15 minutes
MMT blending unit Diagram
The exhaust emission test of gasoline containing MMT
The test showed that the HC and CO emissions of vehicle ran with gasoline with MMT were marginally higher than MMT-free gasoline.
The controversial around the application of MMT
1.The environmentalists argued that Manganese is harmful to the environment and human health.
The research conducted by Ethyl Corp showed that the use of MMT as an antiknock compound, would result in amarginally increase in Manganese in Air. However, Manganese is an essential element,
Manganese within safe limit would not harm human health. The research conducted by China ShanghaiEnvironmental Protection Research Institute also showed that the use of MMT in compliance with the National Standard would not have an significant impact on the environment.
2. The main argument originated from automotive manufacturers. They claimed that MMT would plug the 3-way catalyst, Manganese accumulation on spark plug leading to plugging and malfunctioning,
resulted in an increase in exhaust emissions and poorer fuel economy. The tests conducted by EthylCorp proved otherwise.US EPA evaluated the test data submitted by both parties and arrived at the conclusion that MMT would not harm any emission control system.
3. As a newer, better alternate additive for unleaded
gasoline is not yet available in the market, and the technology level of global refining industry is unable to address the octane constraint, MMT remains the most effective metallic octane improver, the life span of MMT is very strong for many years to come.
Manganese and Health
● Manganese is a trace element, exists naturally in our environment. It is the 12th most abundance element on the earth crust.
● Manganese is the essential growth element for human being, animals and plants. It is the basic element to sustain human’s health.
● In July 1990, US FDA recommended the minimum Manganese intake is 3500 microgram per day.
● Our daily food contain Manganese, Mn also exists inthe air. For example, one cup of tea contains 1200 microgram of Manganese.
● 99% of Manganese intake through ingestion from food and water, Manganese intake through inhalation is less than 1%.
