Difference Between Alkyl Halide and Aryl Halide

关键差异 - 烷基卤素与芳基卤化物

Both alkyl halides and aryl halides are或者ganic compounds.这些也称为有机卤化物。种类halogensthat can be attached in order to produce this type of molecule are氟,氯，溴和iodine。这些卤素原子附着在有机卤化物中的碳原子上。烷基卤化物和芳基卤化物之间的关键区别在于the halogen atom in alkyl halides is attached to a sp³hybridized carbon atom whereas the halogen atom in aryl halides is attached to a sp²hybridized carbon atom.

内容
1.Overview and Key Difference
2.什么是烷基卤化物
3.什么是芳基卤化物
4.Side by Side Comparison – Alkyl Halide vs Aryl Halide in Tabular Form
5.概括

什么是烷基卤化物?

如其名称所表达的烷基卤化物是一种化合物，在碳原子链上附着卤素原子。在这里，一个氢原子碳链被卤素原子取代。根据已附着的卤素类型和碳链结构，有机卤化物的特性将彼此不同。烷基卤化物可以根据附着在卤素原子附着的碳原子上的碳原子进行分类。因此，可以观察到原代烷基卤化物，继发烷基卤化物和三级烷基卤化物。

However, alkyl halides may sometimes be confused with aryl halides. For example, if the halogen atom is attached to a carbon atom, which is attached to a苯ring (Cl-CH₂-C₆H₅), one would think it is an aryl halide. But, it is an alkyl halide because the halogen atom is attached to the carbon that is sp³hybridized.

Halogens are moreelectronegativethan carbon. Thus, a dipole moment is observed in the carbon-halogen bond, that is, the molecule becomes apolarmolecule when the bond becomes polar. The carbon atom gets a small positive charge, and the halogen gets a small negative charge. This leads to偶极 - 偶极相互作用在烷基卤化物之间。但是这种相互作用的强度在主要，次级和第三级卤化物中是不同的。这是因为附着在碳原子上的侧链可以减少碳原子上的微电荷。

什么是芳基卤化物?

芳基卤化物是一个分子aromatic直接响。由于存在，这是一个不饱和的结构double bondsin the aromatic ring. Aryl halides also show the dipole-dipole interactions. The carbon-halogen bond is stronger than that of alkyl halides due to the presence of ring electrons. This happens because the aromatic ring gives electrons to the carbon atom, reducing the positive charge. Aryl halides can undergoelectrophilic substitution并可以将烷基固定在正,段或者metapositions of the aromatic ring. One or two halogens can also get attached to the aromatic ring. That is also in the正,段或者metapositions.

化学测试以区分卤化烷基和芳基卤化物

To distinguish an alkyl halide and an aryl halide, one can use a chemical test. First, NaOH should be added followed by heating. Then the mixture is cooled, and HNO_{3 id}添加，然后添加agno₃。Alkyl halide may give a white precipitate whereas aryl halide does not. That is because, aryl halides do not undergo nucleophilic substitution, unlike alkyl halides. The reason for not undergoing nucleophilic substitution is that the electron cloud of the aromatic ring causes a repulsion of thenucleophile。

烷基卤化物和芳基卤化物有什么区别？

烷基卤素与芳基卤化物
烷基卤化物是一种与碳原子链附着的卤素原子的化合物。	Aaryl halide is a molecule having a halogen atom attached to a sp2hybridized carbon in an aromatic ring directly.
卤素原子的附着
The halogen atom is attached to sp3hybridized carbon atom in alkyl halides.	The halogen atom is attached to a sp2hybridized carbon atom in aryl halides.
Structure
Alkyl halides have a linear or branched structure most of the times.	Aryl halides are always ringed structures.
Electron Density
The carbon-halide bond of alkyl halides has a low density of electrons compared to aryl halides.	The carbon-halide bond of aryl halides has a high density of electrons.
反应
烷基卤化物经历亲核取代。	Aryl halides do not undergo nucleophilic substitution.

概括– Alkyl Halide vs Aryl Halide

Alkyl halides and aryl halides are organic halides. The key difference between alkyl and aryl halide is that the halogen atom in alkyl halides is attached to a sp³hybridized carbon atom whereas in aryl halides it is attached to a sp²hybridized carbon atom.

参考：

1. Hunt, D., n.d. Chem.UCalgary. [Online] Availablehere。[Accessed 30 05 2017].
2. Clark, J., 2014. Libretexts. [Online] Availablehere。[Accessed 30 05 2017].

Image Courtesy:

1. “Halide-group” By Benjah-bmm27 assumed (based on copyright claims). (Public Domain) viaCommons Wikimedia
2.“有机盐 - 氯化物” Richard-59 - üleslaadijaOmaTööööööööööö工作(CC BY-SA 3.0)viaCommons Wikimedia