Relationship between acid amount and framework aluminum content in mordenite

✍ Scribed by Masahiko Sawa; Miki Niwa; Yuichi Murakami

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 540 KB
• Volume: 10
• Category: Article
• ISSN: 0144-2449
• DOI: 10.1016/s0144-2449(05)80308-2

✦ Synopsis

Acid amount of mordenites and dealuminated mordenites with framework aluminum contents of 0.28-2.33 mmol g-1 was measured by temperature-programmed desorption of ammonia. Framework AI content was distinguished from nonframework AI based on 27AI MAS n.m.r, measurements. The relationship between the acid amount and the framework AI content represented a volcano relationship with the maximum acid amount at 1.65 mmol g-1 framework AI content. Below 1.65 mmol g-1 framework AI content, the acid amount was approximately proportional to the framework AI content, whereas the amount decreased as the framework AI content increased above 1.65 mmol g-1. The decrease of acid amount of mordenite with the framework AI content above 1.65 mmol g-1 seems to be due to the generation of nonacidic framework AI atoms owing to paired AI atoms in 4-rings.