Laser-supported high-temperature MAS NMR for time-resolved in situ studies of reaction steps in heterogeneous catalysis.
The temperature of zeolite samples containing various adsorbed molecules was rapidly changed (within 15 s) from room temperature to 600 K by means of a laser beam. The location of the sealed glass ampoule in a boron nitride container decreases the temperature gradient in the sample and avoids laser-induced reactions. The technique facilitates time-dependent magic-angle-spinning (MAS) NMR spectroscopy of high-temperature reactions which take place within 60 s. The H-D exchange in the hydrogen form of zeolites loaded with fully deuterated molecules, the methanol-to-gasoline conversion and the catalytic ethylbenzene disproportionation in zeolites were monitored by 13C and 1H MAS NMR by means of a "stop and go" method.
Ernst
H
H
Universität Leipzig, Abteilung Grenzflächenphysik, Germany.
Freude
D
D
Mildner
T
T
Wolf
I
I
D001555:Benzene Derivatives / Q000737:chemistry; D002247:Carbon Isotopes; D002384:Catalysis; D003903:Deuterium / Q000737:chemistry; D006358:Hot Temperature; D006859:Hydrogen / Q000737:chemistry; D007834:Lasers; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D000432:Methanol / Q000737:chemistry; D017641:Zeolites / Q000737:chemistry
D001555:Benzene Derivatives; D002247:Carbon Isotopes; D017641:Zeolites; D006859:Hydrogen; D003903:Deuterium; C004912:ethylbenzene; D000432:Methanol