[en] The present work consists to to synthezise some microphosphorus materials as SAPO-5, SAPO-11, SAPO-31 and SAPO-34 using hydrothermaly processes and various chemical compositions. The different samples of SAPO-n were characterized by some analytical technics like X-ray diffraction, infra-red spectroscopy, scanning electronic microscopy and chemical analysis. These molecular sieves were used as catalysts in alkylation of ammonia by n-octanol-1 in gaz phase, These obtained results show that the selectivity of monooctylamine (MOA) is higher than di-(DOA) and trioctylamine (TOA) isomers selectivities. It seems that SAPO-5 catalyst favour trioctylamine isomer is formed , in this case, in the external surface of catalyst and obtained in presence of acidic amorphous gels. Also, it has been observed that the increase of surface acidity gives highest catalytic activities