期刊
RAPID COMMUNICATIONS IN MASS SPECTROMETRY
卷 26, 期 17, 页码 1999-2010出版社
WILEY-BLACKWELL
DOI: 10.1002/rcm.6312
关键词
-
资金
- EPSRC
- Commonwealth Scholarship Commission
- Royal Society
- BP Endowment
- EPSRC [EP/F069685/1] Funding Source: UKRI
- Engineering and Physical Sciences Research Council [EP/F069685/1] Funding Source: researchfish
RATIONALE A recently developed miniature electrospray ionisation mass spectrometer has been coupled to a preparative flow chemistry system in order to monitor reactive intermediates and competing reaction paths, screen starting materials, and optimise reaction conditions. Although ideally suited to the application, mass spectrometers have rarely been used in this way, as traditional instruments are too bulky to be conveniently coupled to flow chemistry platforms. METHODS A six-port switching valve fitted with a 5 mu L loop was used to periodically sample the flow stream leaving the reactor coil. Mass spectra corresponding to the sample loop contents were observed approximately 10?s after activating the valve. High fluidic pressure was maintained throughout to ensure that gaseous products remained in solution. As an illustrative example of how this apparatus can be employed, the generation of benzyne and its subsequent reaction with furan were investigated. Benzyne was prepared via diazotisation of anthranilic acid using tert-butyl nitrite. RESULTS Unexpectedly, the explosive diazotised intermediate was detected by the mass spectrometer at low coil temperatures or short residence times. The optimum reactor temperature and residence time for production of the desired Diels-Alder product are 50 degrees C and 35?min, respectively. There are competing reaction pathways leading to the formation of acridone and several other by-products. CONCLUSIONS On-line mass spectrometry allowed the flow conditions to be quickly tuned for safe operation and optimal generation of the desired product. The validity of this approach was corroborated by off-line liquid chromatography/mass spectrometry (LC/MS) analysis of flow samples. Copyright (C) 2012 John Wiley & Sons, Ltd.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据