What role does MTBE play in gasoline?
3 Answers
MTBE has a high octane number and low vapor pressure, which can increase the octane rating of gasoline and reduce vapor emissions. Since MTBE molecules contain oxygen, they help fuel to burn completely, reducing hydrocarbon and carbon monoxide emissions in vehicle exhaust, thus protecting the environment. Tetraethyl lead decomposes into active lead oxide particles under combustion conditions, which act on the surface to destroy peroxides already formed in the car engine, reducing the concentration of peroxides in pre-flame reactions. This selectively interrupts part of the chain reaction, hindering auto-ignition and slowing down the rate of energy release, thereby improving the fuel's anti-knock properties, which means increasing the octane rating of gasoline.
Working with car maintenance daily, MTBE is essentially an anti-knock additive in gasoline. Imagine this: when an engine runs, if the gasoline detonates prematurely, it damages the machinery just like a heart experiencing premature beats. MTBE increases the gasoline's octane rating, making it burn more smoothly and quietly—like giving gasoline a sedative. Moreover, it helps gasoline burn more completely, reducing carbon monoxide and hydrocarbon emissions by about 10%, which improves urban air quality. It was the replacement for leaded gasoline in the past, and although its use is restricted in some areas now, without it, our older cars would have been shaking like sieves long ago.
As someone who frequently researches environmental protection, I see MTBE primarily as an assistant in reducing pollutant emissions. It enables gasoline to burn more completely, significantly reducing black smoke from tailpipes. I remember when clean gasoline was being promoted around 2000, MTBE played an indispensable role. Nowadays, the ability to differentiate between 92 and 95 octane gasoline at gas stations based on varying anti-knock levels relies on such additives. However, its high solubility in water means that storage tank leaks can contaminate groundwater, which is why Europe and America are gradually replacing it with ethanol. Nevertheless, in domestic refining processes, MTBE still offers a better cost-performance ratio.
