Synthesis of di(methylphenyl)methane over heteropolyacids (H3PW12O40) catalysts.

Catalytic synthesis of di(methylphenyl)methane (CH3C6H4CH2C6H4CH3, DMPMs) from toluene and formaldehyde were investigated over various solids acids. At 140 °C and toluene/HCHO = 5/1, the conversion of HCHO over zeolite (Hβ, H-mordenite, HX, HY and HZSM-5) is limited, while heteropolyacids (H3PW12O40, H4SiW12O40 and H3PMo12O40) exhibited higher activity and DMPMs selectivity. The best yield of DMPMs reached 81.5% (conversion of HCHO nearly 100%). H3PW12O40 could be recovered by simply drying and the recycle-used catalyst remained its activity and structure in five runs. [ABSTRACT FROM AUTHOR]