Ammoxidation of picolines over modified silicoaluminophosphate molecular sieves

Silicoaluminophosphate (SAPO) and modified SAPOs, such as Sb-V-SAPO-5, Mo-V -SAPO-5 and Mn-V-SAPO-5, have been prepared. XRD and FT-IR were used to cha racterize the catalysts and confirm preservation of crystallinity after var ious treatments. The modified SAPOs are highly active (>90% yield) in the a mmoxidation of 4-picoline and 3-picoline (>85%). The crystalline Sb-V-SAPO- 5 was more active in the ammoxidation of 3-picoline compared to the amorpho us catalysts ill current use. The modification by vanadium, and antimony, m olybdenum or manganese improved the yield of 4-cyano and 3-cyanopyridine. W e have modified proposed V-SAPO-S molecular sieve as the active catalyst fo r the ammoxidation of picolines. (C) 2000 Elsevier Science B.V. All rights reserved.