Preparation Of SAPO-41 Molecular Sieve And Its Catalytic Alkylation Reaction Of Naphthalene

In this paper,SAPO-41 molecule sieves with different Si/Al ratio were synthesized by traditional hydrothermal method using di-n-propylamine?DPA?and di-n-butylamine?DBA?as templates,the structure and acidity were characterized by XRD,SEM,N₂ physical adsorption,NH₃-TPD and Py-IR,used as catalysts in probe reaction of alkylation of naphthalene with methanol to evaluate their catalytic performances.The results indicated that the type of template has influence on structure,acidity and catalytic performance of molecule sieves.S41?0.4?-B has the excellent catalytic performance in the reaction of alkylation of naphthalene with methanol,when the conversion of naphthalene equaled to 60.0%,the selectivity for 2,6-DMN and the ratio of 2,6-/2,7-DMN reached 34.8%and 1.5,respectively.MgAPO-41 and CoAPO-41 molecule sieves were synthesized with magnesium nitrate and cobalt nitrate,respectively.The structure,acidity and catalytic performance of catalysts were investigated.The results indicated that the introduction of Co²⁺as the cobalt or Mg²⁺as the magnesium,replacing silica source,can form abundant acid sites.The CoA41?0.06?catalyst showed excellent stability and high catalytic activity,when the conversion of naphthalene equaled to 61.2%,the selectivity for 2,6-DMN reached27.5%.SAPO-41 molecule sieves were modified by dealumination treatment using citric acid.The effect of acid treatment time on the structure,acidity,and catalytic performance in the alkylation of naphthalene was investigated.It showed that the skeleton structure of SAPO-41molecular sieves were breaken after long treatment time and the catalytic performance reduced.CA-S41-2h molecule sieve with treatment time of 2 h possessed the best catalytic performance in the reaction of alkylation of naphthalene with methanol.A series of hierarchical SAPO-41 molecule sieves were synthesized by addi ng different contents of[3-?trimethoxysilyl?propyl]hexadecyldimethylammonium chloride?TPHAC?as mesoporous templates.The hierarchical S41-0.02T molecul e sieve with the content of 0.02 mol of TPHAC possessed larger mesoporous v olume,leading to higher catalytic activity and selectivity for 2,6-DMN.When th e conversion of naphthalene equaled to 60.7%,the 2,6/2,7-DMN reached 1.6.