Global warming is an important problem that affects human life, animals and plants. Emissions during the combustion of fossil fuels, such as carbon dioxide, NOx, SOx etc. are reported to contribute to this problem extremely. Nowadays, alcohols and ethers are considered as attractive alternative fuels due to their good burning properties and less carbon emissions. Dimethyl ether (DME) is one of the most promising alternates of such synthetic fuels. In methanol dehydration reaction to produce DME, solid acid catalysts, such as γ-Alumina and modified γ-Alumina, Na-modified H-ZSM-5, mesoporous alumino silicate were tested. These catalysts are porous solid with low thermal conductivity. The reaction heat is difficult to be transferred and the diameter of single tube of the reactor has to be limited to several centimeters in order to control the temperature of the hot spots in the fixed bed reactors. Also carbon nanotubes (CNTs) are desirable for many applications because of their high surface area to weight ratio and excellent thermal conduction property. Through this book CNTs was used for improvement of catalysts for dehydration of methanol to DME.