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Section IV Olefin Nole hydrocarbons are chain hydrocarbons containing carbon-carbon triple bonds (-C≡C-).
.. R-C≡CH or R'C≡C-R" can represent their tectonics, carbon triple bond (-C≡C-) is the official energy group of hydrocarbons.
.
hydrocarbons are also unsaturated hydrocarbons, and the general . n
H2n-2
, the same as dolefins or cyclolefins.. I. The isomer phenomenon and nomenclament of olefin hydrocarbonsiso-hydrocarbons also have iso-isomer phenomena due to the difference between carbon chain structure and three-bond position. However, due to the location of the three-bond branch chain, the number of isomers is less than that of olefins with the same number of carbon atoms. For example, a hydrocarbon containing five carbon atoms has only three isomer:
the nomenclat is similar to olefins. For example:II, the physical properties of hydrocarbonsIn the same series of positive hydrocarbons, C2 to C4 hydrocarbons are gases, C5 to C15 is liquid, C15 is solid. The melting and boiling points of hydrocarbons also increase with the increase in the number of carbon atoms (Tables 11-5).
. Table 11-5 Physical Constant of Olefin Hydrocarbons Name Tectonic Melting Point/C Boiling Point/C Relative Density (d204) Acetylene HC≡CH -81.8 -83.6 - Acrylic CH3C≡CH -101.51 -23.2 - 1-Ding CH3CH2C≡CH -122.5 8.1 - 2-butylen CH3C≡CCH3 -32.3 27 0.691 1-CH3 (CH2) C≡CH -90 29.3 0.695 2-Ch CH3CH2C≡CH -101 55.5 0.714 1-hetero-CH3 (CH2)3C≡CH -132 71 0.715 2-hetero-CH3 (CH2)2C≡CH -88 84 0.730 3-hetero-CH3CH2C≡CCH3 -51 81.8 0.724 1-ch3 (CH2)4C≡CH -81 100 0.734 2-ch2 CH3 (CH2) 3C≡CCH3 - 112. 0.748 3-Ch2(CH2)2C≡CCH3 - 105 0.752 1-Sinn CH3 (CH2)5C≡CH -80 125.2 0.746 2-Sinn CH3 (CH2) 4C≡CCH3 -80 60.2 137.2 0.759 3-Sinn CH3 (CH2)C≡CCH2CH3 -105 133 0.752 4-Sinn CH3 (CH2) 2C≡C (CH2)2CH3 -102 131 0.2 751 1-Ch2 CH3 (CH2)6C≡CH -65 160.7 0.760 2-Yuan CH3 (CH2)5C≡CCH3 - 155747 0.769 3-Ch2 4C≡CCH2CH2 3 - 154745 0.762 4-Ch2 3C≡C (CH2)2CH3 - 152752 0.757 1-Ch2(CH2) 7C≡CH -44 0.765 3-yuan CH3 ( CH2) 5C≡CCH2CH3 - 0.765 3, the chemical properties of olefins the official energy group of olefins is -C≡C-, it has two π bonds, has a weaker affinity (Lewis alkali), the chemical properties and olefins have many similarities, such as the ability to add, oxidation and polyreact reactions. In addition, the ≡-C-H C-H has different properties than
σ keys, i.e. very weak acidity. . (i) A plus reaction
1. Hydrocarbon
under the action of catalysts (Pt, Pd or Ni), olefins and hydrogen are added to produce olefins, which eventually produce alkanes.
.
2. Halogen-
hydrocarbons can be added to chlorine or bromine. The reaction was carried out in two steps, with the first addition of 1mol reagent to produce a dihalide derivative of olefins and the second addition of 1mol reagent to produce four halogens. For example
the addition of hydrogen and hydrogen halide are also carried out in two steps.
. . 1,1-D-ethane In the resulting vinyl bromide molecule, the unsharing electrons of bromine atoms play a major role in conjugated systems (p-π conjugates) with π bonds, where conjugate effects play a secondary role, while the induced effects of bromine atoms are secondary. Thus, when added to the second hydrogen bromide molecule, the bromine atom continues to be added to the carbon atom that already has one bromine, producing CH3CHBr2. . Asymmetric olefin hydrocarbons and HX are added in compliance with the Mars rule. In the presence of oxides, the addition reaction of asymmetric olefin hydrocarbons and HBr is anti-Mars rule.
. (ii) When oxidation
hydrocarbons, the carbon chain breaks at the three bonds. For example, when acetylene is oxidized with potassium permanganate, carbon dioxide is produced.
.
other hydrocarbons are oxidized with potassium permanganate to produce pyric acid. .
the purple disappearance of potassium permanganate from the reaction results, so this reaction can also be used to check the carbon triple bond. . (iii) Polymerization reaction
acetylene under different catalysts and reaction conditions, a variety of polymerization reactions occur to produce chain-like or ring-like
compounds
. If acetylene occurs in the case of a two-molecule polymerization reaction, vinyl acetylene CH2 is produced, CH-C≡CH, and in the presence of a suitable catalyst, acetylene polymerization of three molecules into benzene.
. . (iv) The generation of the carbide is connected to the C≡C carbon atom hydrogen atom is quite lively, because the three-bond C is sp hybridization, s composition accounts for 1/2, the electron negative is relatively strong, so that the Csp-H1s bond of the electron cloud closer to the carbon atom, enhance the C-H bond polarity, so that the hydrogen atom is easy to dissocute, showing acidity. Acetylene-based anion energy is low and the system is stable, so hydrogen atoms in the acetylene molecule CH≡CH are easily replaced by metals, and the resulting hydrocarbon metal derivatives are called ethylene. For example, the acetylene into a silver nitrate ammonia solution or
.