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Time resolved growth of (N)-polycyclic aromatic hydrocarbons in engine deposits uncovered with OrbiSIMS depth profiling
Analyst ( IF 3.6 ) Pub Date : 2022-07-29 , DOI: 10.1039/d2an00798c Max K Edney 1 , Wenshi He 2 , Emily F Smith 3 , Edward Wilmot 4 , Jacqueline Reid 4 , Jim Barker 4 , Rian L Griffiths 2 , Morgan R Alexander 2 , Colin E Snape 1 , David J Scurr 2
Analyst ( IF 3.6 ) Pub Date : 2022-07-29 , DOI: 10.1039/d2an00798c Max K Edney 1 , Wenshi He 2 , Emily F Smith 3 , Edward Wilmot 4 , Jacqueline Reid 4 , Jim Barker 4 , Rian L Griffiths 2 , Morgan R Alexander 2 , Colin E Snape 1 , David J Scurr 2
Affiliation
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Carbonaceous deposits are ubiquitous, being formed on surfaces in engines, fuel systems and on catalysts operating at high temperatures for hydrocarbon transformations. In internal combustion engines, their formation negatively affects worldwide vehicle emissions and fuel economy, leading to premature deaths and environmental damage. Deposit composition and formation pathways are poorly understood due to their insolubility and the intrinsic complexity of their layered carbonaceous matrix. Here, we apply the in situ high mass resolving power capabilities of 3D Orbitrap secondary ion mass spectrometry (3D OrbiSIMS) argon cluster depth profiling on 16 lab grown deposits and evidence common molecular distributions in deposit depth and in positions relative to the combustion chamber. We observe the products of the growth of both planar and curved polycyclic aromatic hydrocarbons to form small fullerenes over time in the engine and propose possible formation pathways which explain the molecular distributions observed. These include alkyl scission, cyclisation of aliphatic side chains and hydrogen abstraction C2H2 addition to form larger aromatic structures. We apply this pathway to previously unidentified nitrogen containing structures in deposits including quinolines and carbazoles. For the first time, 3D OrbiSIMS results were compared and validated with data from atmospheric pressure matrix assisted laser desorption ionization MS. The comprehensive characterization provided will help the development of a new generation of chemical additives to reduce deposits, and thus improve vehicle emissions and global air quality.
中文翻译：
OrbiSIMS 深度剖析发现的发动机沉积物中 (N)-多环芳烃的时间分辨生长
碳质沉积物无处不在，形成在发动机、燃料系统的表面以及在高温下用于烃转化的催化剂上。在内燃机中，它们的形成会对全球车辆排放和燃油经济性产生负面影响，导致过早死亡和环境破坏。由于沉积物的不溶解性和层状碳质基质的内在复杂性，人们对沉积物的组成和形成途径知之甚少。在这里，我们就地应用3D Orbitrap 二次离子质谱 (3D OrbiSIMS) 氩簇深度剖析对 16 个实验室生长的沉积物的高质量分辨能力，并证明沉积物深度和相对于燃烧室的位置的常见分子分布。我们观察到平面和弯曲的多环芳烃随着时间在发动机中形成小富勒烯的产物，并提出了解释观察到的分子分布的可能形成途径。这些包括烷基断裂、脂肪族侧链的环化和夺氢 C 2 H 2除了形成更大的芳香结构。我们将此途径应用于沉积物中先前未鉴定的含氮结构，包括喹啉和咔唑。首次将 3D OrbiSIMS 结果与来自大气压基质辅助激光解吸电离 MS 的数据进行了比较和验证。所提供的综合特性将有助于开发新一代化学添加剂以减少沉积物，从而改善车辆排放和全球空气质量。
更新日期：2022-07-29
中文翻译：
OrbiSIMS 深度剖析发现的发动机沉积物中 (N)-多环芳烃的时间分辨生长
碳质沉积物无处不在，形成在发动机、燃料系统的表面以及在高温下用于烃转化的催化剂上。在内燃机中，它们的形成会对全球车辆排放和燃油经济性产生负面影响，导致过早死亡和环境破坏。由于沉积物的不溶解性和层状碳质基质的内在复杂性，人们对沉积物的组成和形成途径知之甚少。在这里，我们就地应用3D Orbitrap 二次离子质谱 (3D OrbiSIMS) 氩簇深度剖析对 16 个实验室生长的沉积物的高质量分辨能力，并证明沉积物深度和相对于燃烧室的位置的常见分子分布。我们观察到平面和弯曲的多环芳烃随着时间在发动机中形成小富勒烯的产物，并提出了解释观察到的分子分布的可能形成途径。这些包括烷基断裂、脂肪族侧链的环化和夺氢 C 2 H 2除了形成更大的芳香结构。我们将此途径应用于沉积物中先前未鉴定的含氮结构，包括喹啉和咔唑。首次将 3D OrbiSIMS 结果与来自大气压基质辅助激光解吸电离 MS 的数据进行了比较和验证。所提供的综合特性将有助于开发新一代化学添加剂以减少沉积物，从而改善车辆排放和全球空气质量。
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