Mahalaxmi Group of Companies offers Methyl Tertiary Butyl Ether. Mahalaxmi Group of Companies supplies chemical and petrochemical products. Methyl Tertiary Butyl Ether, also known as methyl tertiary butyl ether and MTBE, is a chemical compound with molecular formula C5H12O. MTBE is a gasoline additive, used as an oxygenate and to raise the octane number. MTBE is also used in organic chemistry as a relatively inexpensive solvent with properties comparable to diethyl ether but with a higher boiling point and lower solubility in water. It is also used medically to dissolve gallstones.