EXTERNAL MODIFICATION OF ZEOLITE BY METAL SURFACTANT FOR METHANOL AMINATION

HZSM-5 was modified by the surfactant magnesium valerate. The adsorpti on of the surfactant on HZSM-5 was studied. The total acidities of zeo lites were measured by ammonia TPD before and after the modification. The activities and selectivities of methanol amination over the zeolit es were evaluated. The results indicated that: (1) the modification co uld increase total selectivities of monomethylamine (MMA) and dimethyl amine (DMA) without evident loss of activity. (2) Two modifications tr eatments could give higher total selectivity than one treatment: so di d a lower heating rate of calcination. (3) The total selectivity rose with an increase of Mg content of the modified zeolites. (4) A single layer adsorption of the surfactant molecules on external surface of ze olites could be obtained. (5) The total acidities of modified zeolites decreased and approached a constant with an increase of Mg content. ( C) 1998 Elsevier Science B.V. All rights reserved.