High-resolution NMR process analyzer for oxygenates in gasoline
High-resolution NMR process analyzer for oxygenates in gasoline
复制标题
汽油中含氧物的高分辨率核磁共振过程分析仪
DOI：
10.1021/ac00076a019
复制
发表时间：
1994
影响因子：
7.4
通讯作者：
J. F. Haw
中科院分区：
文献类型：
--
作者：
Timothy W. Skloss;Ae Ja Kim;J. F. Haw
我们报告了一个高分辨率的42 MHz[sup 1]HFT-NMR仪器，适合用作过程分析仪，并证明其用于测定流动的汽油流中的甲基叔丁基醚（MTBE）。该光谱仪是基于一个55公斤的永久磁铁，基本上没有边缘场。对于旋转样品，通常获得3 Hz的光谱分辨率，并且对于流动样品，该性能仅略微降低。我们报告了一个程序，使用软件程序，而不是一个磁场频率锁定通道的磁铁漂移补偿。该程序允许信号平均而不损失分辨率。在不久的将来将要实施的法规变化需要开发用于测定重新配制的汽油中的MTBE和其他含氧化合物的方法。采用气相色谱法的现有方法对于汽油混合器的过程控制来说不够快，并且受到其他限制。本研究表明，过程分析核磁共振是非常适合的模拟汽油混合器中的MTBE的测定。测量时间为1分钟，检测限为0.5体积%甲基叔丁基醚。当甲基叔丁基醚浓度为10%（名义值）时，独立测定的绝对标准偏差为0.17%。初步结果还表明，该方法可适用于汽油含有的混合物的添加剂，以及芳香族和烯属氢的测量。参考文献33篇，图9。«少
We report a high-resolution 42-MHz[sup 1]HFT-NMR instrument that is suitable for use as a process analyzer and demonstrate its use in the determination of methyl tert-butyl ether (MTBE) in a flowing stream of gasoline. This spectrometer is based on a 55-kg permanent magnet with essentially no fringe field. A spectral resolution of 3 Hz was typically obtained for spinning samples, and this performance was only slightly degraded with flowing samples. We report a procedure for magnet drift compensation using a software procedure rather than a field-frequency lock channel. This procedure allowed signal averaging without loss of resolution. Regulatory changes to be implemented in the near future have created a need for the development of methods for the determination of MTBE and other oxygenates in reformulated gasolines. Existing methods employing gas chromatography are not fast enough for process control of a gasoline blender and suffer from other limitations. This study demonstrates that process analysis NMR is well-suited to the determination of MTBE in a simulated gasoline blender. The detection limit of 0.5 vol % MTBE was obtained with a measurement time of 1 min. The absolute standard deviation of independent determinations was 0.17% when the MTBE concentration was 10%, a nominalmore » value. Preliminary results also suggest that the method may be applicable to gasolines containing mixtures of oxygenate additives as well as the measurement of aromatic and olefinic hydrogens. 33 refs., 9 figs.« less