Issue 1, 2018, Issue in Progress

Shape-selective methylation of naphthalene with methanol over SAPO-11 molecular sieve modified with hydrochloric acid and citric acid

Abstract

Herein, a series of SAPO-11 molecular sieves were modified by citric acid and hydrochloric acid. They were characterized by ICP, XRD, SEM, N2 adsorption–desorption, NH3-TPD, 29Si MAS NMR, and Py-IR and evaluated by the methylation of naphthalene with methanol to 2,6-dimethylnaphthalene (2,6-DMN). According to the XRD results, hydrochloric acid at a high concentration not only removed extra-framework aluminum but also deleted framework silicon; this resulted in the formation of crystal defects. N2 adsorption–desorption results showed that all the samples possessed micropores and secondary mesopores. The SAPO-11 sample modified with 4 mol L−1 hydrochloric acid for 30 min exhibited the largest secondary mesopore size distributions. NH3-TPD and 29Si MAS NMR showed that hydrochloric acid at a high concentration could eliminate more acid sites. SAPO-11 modified with 4 mol L−1 hydrochloric acid for 30 min presented high catalytic performance for the methylation of naphthalene; this was mainly attributed to the amount of secondary mesopores in the SAPO-11 molecular sieves.

Graphical abstract: Shape-selective methylation of naphthalene with methanol over SAPO-11 molecular sieve modified with hydrochloric acid and citric acid

Article information

Article type
Paper
Submitted
01 Nov 2017
Accepted
07 Dec 2017
First published
02 Jan 2018
This article is Open Access
Creative Commons BY license

RSC Adv., 2018,8, 243-250

Shape-selective methylation of naphthalene with methanol over SAPO-11 molecular sieve modified with hydrochloric acid and citric acid

X. Wang, Z. Liu, F. Guo, Y. Wang, X. Wei, P. Li, Y. Xue, Y. Wang, S. Guo and Y. Yu, RSC Adv., 2018, 8, 243 DOI: 10.1039/C7RA12009E

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