二、炔烃的物理性质

在正炔烃的同系列中，C2～C4的炔烃是气体，C5～C15的是液体，C15以上的是固体。炔烃的熔点和沸点也随着碳原子数目的增加而增高（表11-5）。

表11-5炔烃的物理常数

名称 构造式 熔点/℃ 沸点/℃ 相对密度(d204)
乙炔 HC≡CH -81.8 -83.6 -
丙炔 CH3C≡CH -101.51 -23.2 -
1-丁炔 CH3CH2C≡CH -122.5 8.1 -
2-丁炔 CH3C≡CCH3 -32.3 27 0.691
1-戊炔 CH3(CH2)C≡CH -90 29.3 0.695
2-戊炔 CH3CH2C≡CH -101 55.5 0.714
1-己炔 CH3(CH2)3C≡CH -132 71 0.715
2-己炔 CH3(CH2)2C≡CH -88 84 0.730
3-己炔 CH3CH2C≡CCH3 -51 81.8 0.724
1-庚炔 CH3(CH2)4C≡CH -81 100 0.734
2-庚炔 CH3(CH2)3C≡CCH3 - 112 0.748
3-庚炔 CH3(CH2)2C≡CCH3 - 105 0.752
1-辛炔 CH3(CH2)5C≡CH -80 125.2 0.746
2-辛炔 CH3(CH2)4C≡CCH3 -60.2 137.2 0.759
3-辛炔 CH3(CH2)C≡CCH2CH3 -105 133 0.752
4-辛炔 CH3 (CH2) 2C≡C(CH2)2CH3 -102 131 0.751
1-壬炔 CH3(CH2)6C≡CH -65 160.7 0.760
2-壬炔 CH3(CH2)5C≡CCH3 - 155747 0.769
3-壬炔 CH3(CH2)4C≡CCH2CH3 - 154745 0.762
4-壬炔 CH3(CH2)3C≡C(CH2)2CH3 - 152752 0.757
1-癸炔 CH3(CH2)7C≡CH -44 0.765
3-癸炔 CH3(CH2)5C≡CCH2CH3 - 0.765