在有機化學(xué)中，烷基取代物是缺少一個氫的烷烴。烷基一詞故意不具體，包括許多可能的取代。無環(huán)烷基具有通式CNH2N+ 1。環(huán)烷基是由環(huán)烷烴通過從環(huán)上除去氫原子而得到的，具有通式CnH2n-1。通常烷基是大分子的一部分。在結(jié)構(gòu)式中，符號R用于指定一個通用的（未指定的）烷基。最小的烷基是甲基，其分子式為CH3。
2-Ethylhexyl methacrylate
2-Fluoro-5-methylnicotinonitrile
(5-Methyl-1H-indol-2-yl)methanol
(4-(Isopropylcarbamoyl)phenyl)boronic acid
6-Fluoro-2-methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline
3-Methyl-2-cyclohexen-1-one
2-Methylundecanoic acid
3-(3-Methyl-3H-diazirin-3-yl)propanoic acid
1-(Chloromethyl)-2-methylbenzene
2-Methylbenzylmercaptan
3-([1,1'-Biphenyl]-4-yl)-5-(4-(tert-butyl)phenyl)-4-phenyl-4H-1,2,4-triazole
3,5-Diethylpyridine
2-Amino-4-(methylselanyl)butanoic acid
N-octylpyridinium bromide
6-Isobutylpyridin-3-amine
6-Isopropylpicolinamide
2,5-Diisopropylphenol
1-Pentylpiperazine dihydrochloride
5-(5-Methylfuran-2-yl)-1H-pyrrole-2-carboxylic acid
3-Bromo-2,4-dimethylphenol
4,4,6-Trimethyl-1,3,2-dioxaborinane
3-Bromo-2,2-bis(bromomethyl)propyl acetate
2-((3-Methoxyphenyl)ethynyl)-6-methylpyridine hydrochloride
tert-Butyl (1-(methoxy(methyl)amino)-1-oxopropan-2-yl)carbamate
Methyl 9-bromononanoate
(1R)-1-(Thiophen-2-yl)ethan-1-amine
Ethyl(methoxy)amine hydrochloride
1-(6-Cyclopropylpyridin-3-yl)ethanamine
4,4-Dimethylcyclopentane-1,3-dione
Bis(2-ethylhexyl) cyclohexane-1,2-dicarboxylate
