Conversion of methanol to light olefins over H‐MCM‐22 dealuminated with different methods

Abstract

Background In the post‐oil society, the methanol‐to‐olefin (MTO) conversion is a successful non‐oil route for the production of ethene, propene and butene, which are important chemicals in modern chemical industry. Recently, the global demand for propene increased, which makes high propene selectivity attractive in the MTO conversion. However, looking for an effective catalyst is the main challenge. Results H‐MCM‐22 zeolite was dealuminated with nitric acid, oxalic acid and ammonium hexafluorosilicate (AHFS). Then, the parent and dealumianted samples were examined in the MTO reaction. The results showed that the total acid amounts decreased and the distribution of Brőnsted acid sites in the pores of H‐MCM‐22 were reregulated after the different dealumination procedures. The results of thermogravimetric (TG) analysis of the spent samples demonstrated that H‐MCM‐22 (10A) dealumination with 10 mmol L−1 AHFS solution had the lowest coking rate and coke selectivity, which makes it exhibit the longest lifetime (54 h), and highest propene and butene selectivity (71.8%). Conclusion Dealumination with AHFS is an effective method for H‐MCM‐22. Because it can eliminate almost all the extra‐framework aluminum (AlEF) species and concentrate the Brőnsted acid sites in the sinusoidal channels which promote the propene and butene formation with a resistance to carbonaceous deposition in the MTO reaction. © 2016 Society of Chemical Industry

A Supramolecular View on the Cooperative Role of Brønsted and Lewis Acid Sites in Zeolites for Methanol Conversion

“…65,72−74 This postsynthetic modification is also known to increase propene selectivity and catalyst lifetime. 69,75,76…”

“…65,72−74 This postsynthetic modification is also known to increase propene selectivity and catalyst lifetime. 69,75,76 For both alkaline-earth metal modifications and EFAl species, the nature and role of LASs on the zeolite supramolecular function for the methanol conversion will be investigated. Although some theoretical insights on the effect of Lewis acid sites on methanol conversion were already obtained, a systematic spectroscopic, energetic, and reactivity study at the molecular level is not available for metal containing clusters.…”

“…Such modification of the catalyst would suppress the aromatic cycle . Additionally, dealumination of zeolites is known to lead to formation of both mesopores and extra-framework aluminum (EFAl) species, which exhibit a Lewis acid nature. ,− This postsynthetic modification is also known to increase propene selectivity and catalyst lifetime. ,, …”

Preparation of biomass‐derived phosphorus‐doped microporous carbon material and its application in dye adsorption and CO2 capture

“…In order to evaluate the oxidation resistance of its adsorbent, TGA was carried out on 0.075‐PC, and the results are shown in Figure 2. The weight loss at low temperature is attributed to the desorption of physically adsorbed water 47 . It can be seen that the sample heated by air will decompose rapidly when the temperature exceeds 500°C.…”

“…The weight loss at low temperature is attributed to the desorption of physically adsorbed water. 47 It can be seen that the sample heated by air will decompose rapidly when the temperature exceeds 500 C.…”