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Gas‐phase ion–molecule reactions in dilute mixtures of dimethyl ether in krypton. Bimolecular and clustering reactions
Author(s) -
Illies Andreas J.
Publication year - 1990
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210250115
Subject(s) - chemistry , krypton , electron ionization , dimethyl ether , ion , onium , fragmentation (computing) , adduct , chemical ionization , molecule , ether , ionization , mass spectrometry , polyatomic ion , photochemistry , analytical chemistry (journal) , xenon , organic chemistry , methanol , chromatography , operating system , computer science
The results of high‐pressure variable‐temperature and variable ionizing electron energy studies of gas‐phase ion‐molecule reactions of dimethyl ether in krypton are presented. Near the ionization threshold a series of peaks corresponding to (CH 3 OCH 3 ) n H + ( n = 1‐4) clusters are observed. At higher ionizing electron energies, two new series of peaks appear, corresponding to [CH 3 OCH 2 ] + (CH 3 OCH 3 ) n and [(CH 3 ) 3 O] + (CH 3 OCH 3 ) n clusters. The onium ion, [(CH 3 ) 3 O] + , has been previously reported at elevated temperatures under methane chemical ionization conditions. It was suggested that the onium ion is formed by reaction of (CH 3 ) 2 OH + with CH 3 OCH 3 with subsequent elimination of methanel, i.e. by fragmentation of an adduct ion. The present results strongly suggest that, under our conditions, [CH 3 OCH 2 ] + rather than thermal (CH 3 ) 3 OH + , is the precursor to [(CH 3 ) 3 O] + .