Theory analysis of mass spectra of long-chain isocyanates.
Electron impact mass spectra of four long-chain isocyanates, lauryl isocyanate, tetradecyl isocyanate, hexadecyl isocyanate and octadecyl isocyanate, were obtained with a GCT high-resolution time-of-flight mass spectrometer. The four isocyanates studied gave a common base peak of m/z 99, which suggested the formation of a stable six-membered ring structure to decentralize the positive charge. Quantum-mechanical energy calculation justified that the six-membered ring base peak had the lowest energy. The positive charge assigned during the fragmentation of the radical cation, and the relative intensity of the fragment ion peaks, were explained by quantum-mechanical calculations as well.
Key Laboratory of Science & Technology of Eco-Textile, Ministry of Education, Donghua University, North Renmin Road 2999th, Shanghai 201620, PR China. dut_liud@yahoo.com.cn
Dongliang
D
Liu
Ce
C
Hao
Hua
H
Zhang
Weihong
W
Qiao
Zongshi
Z
Li
Guanghui
G
Yu
Kelu
K
Yan
Yuliang
Y
Guo
Lvbo
L
Cheng
D003198:Computer Simulation; D017953:Isocyanates / Q000032:analysis* / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D011789:Quantum Theory
D017953:Isocyanates