概括
对墨西哥湾表面样本中空海界面基的分析揭示了意想不到的甲基分支基和环基. 这些发现表明,自然生物源与人类活动一起有着重要的贡献.
科学领域:
- 环境化学环境化学
- 海洋有机地化学 海洋有机地化学
背景情况:
- 基是海洋环境中普遍存在的有机化合物.
- 了解空气海界面的基源对于评估海洋污染和生物地化学循环至关重要.
研究的目的:
- 分析组合并确定空海界面上存在的基的来源.
- 为了研究不同海洋地点的烯分布的季节性变化.
主要方法:
- 在12个月内从蒂姆巴利尔湾,路易斯安那州沿海和佛罗里达州沿海收集了118个表面样本.
- 使用气体染色学和质谱学对化合物的表征.
主要成果:
- 甲基分支基 (C15-C35) 和环基常常是主要成分.
- 这些化合物的存在表明来自自然和人为来源的混合起源.
结论:
- 研究区域的空海界面受到自然生物过程和人类活动的结合的影响.
- 需要进一步的研究,以充分阐明具体的生物来源及其对海洋酸盐负载的贡献.
相关概念视频
Mass Spectrometry: Long-Chain Alkane Fragmentation
The molecular ions of linear alkanes prefer to fragment at the carbon-carbon bond away from the end of the chain since the cleavage of an inner bond creates a stable carbocation and a stable radical. Consequently, the mass signals of linear alkanes feature intense peaks in the middle of the mass-to-charge ratio plot with weaker peaks on either end. The fragmentation of each carbon-carbon bond with the release of a methyl group in each splitting leads to prominent peaks in the mass spectra...
Conformations of Ethane and Propane
In an organic molecule, free rotation about the carbon-carbon single bond results in energetically different conformers of the molecule. Due to this rotation, called the internal rotation, ethane has two major conformations — staggered and eclipsed.
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered ethane, the...
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered ethane, the...
Nomenclature of Alkanes
In the late 19th-century, the number of new chemical compounds discovered increased tremendously. Hence, the necessity arose to develop a naming system for the systematic nomenclature of these newly discovered compounds. IUPAC (International Union for Pure and Applied Chemistry), established in 1919, sets rules for the nomenclature.
The alkane nomenclature considers the length of the carbon chain, the number, and the location of the substituent to arrive at its systematic name. The IUPAC...
The alkane nomenclature considers the length of the carbon chain, the number, and the location of the substituent to arrive at its systematic name. The IUPAC...
Constitutional Isomers of Alkanes
Organic compounds of the same molecular formula can have different structural formulas called constitutional isomers, and the phenomenon is known as constitutional isomerism. Alkanes with four or more carbons showing multiple structures with the same molecular formula thereby exhibit constitutional isomerism.
The linear isomer of an alkane is prefixed by the term “n”; hence a linear isomer of pentane is known as n-pentane. Based on the type of branching, some of the branched isomers are given...
The linear isomer of an alkane is prefixed by the term “n”; hence a linear isomer of pentane is known as n-pentane. Based on the type of branching, some of the branched isomers are given...
Conformations of Butane
Unlike ethane and propane that have only two major conformations, butane has more than two conformers. The staggered form of butane in which the bulky methyl groups on the two carbons are placed on opposite sides, that is, at a dihedral angle of 180°, is the lowest energy, most stable form — called the anti conformer. This conformation is stabilized due to the absence of steric repulsion between the largely spaced out methyl groups. The other two staggered conformations are degenerate and have...
Physical Properties of Alkanes
Alkanes are nonpolar molecules due to the presence of only carbon and hydrogen atoms. The electronegativity difference between carbon and hydrogen is minimal, and hence alkanes have a zero dipole moment. This leads to the presence of only dispersion forces between the molecules. The strength of dispersion forces is dependent on the surface area of the molecules on which they act. Since the surface area increases with the molecular length for straight-chain alkanes, the dispersion forces also...


