Ethylenic and acetylenic groups

In addition to inorganic radicals, which profoundly modify the properties of a paraflSn hydrocarbon residue, there is a whole series of organic groupings which are distinguished by exceptional reactivity, for example, the ethylene and acetylene groupings, and the phenyl and naphthyl radicals. Thus the characterisation of unsaturated hydrocarbons and their derivatives, e.g., the aromatic compounds, becomes possible. 

The Effect of Ethylenic and Acetylenic Groups on the Properties of Fatty Acid Monolayers... 

Fischer, C.E., Raith, A., Mink, J., Raudaschl-Sieber, G., Cokoja, M., and Kiihn, F.E. 2011. Organic-inorganic nanotube hybrids Organosilica-nanotubes containing ethane, ethylene and acetylene groups. J. Organometal. Chem. 696 2910-2917. 

While (Z)-l,2-bis(phenylsulfonyl)ethylene (140) does not add to dienes such as furan, cyclopentadiene, cyclo-octatetraene, indene and )S-naphthol, ( )-l,2-bis(phenylsulfonyl)ethylene (141) is more reactive and the reaction with furan proceeds at room temperature for 2 h to give the adduct in 95% yield. The reactivity of dienophiles having sulfonyl group in the [4 -t- 2]cycloaddition is shown in equation 103 °X Due to the low reactivity of ethylene and acetylene as dienophiles, forcing conditions, such as high temperature and high pressure, are necessary for [4 -1- 2]cycloaddition. The hazards associated with handling acetylene under these conditions are well known and... 

The reactivity of the dienophile depends on the electron demand of the reaction. Electron-withdrawing groups in the dienophile will accelerate the reaction rate. Simple alkenes and alkynes such as ethylene and acetylene are poor dienophiles. In the following table some representative dienophiles have been tabulated along with their reaction with cyclopentadiene. 

Similar calculations have been made for compounds with two groups X and X on one ring, where the other ring systems such as naphthalene34 and heterocyclic rings,35 and for ethylenic and acetylenic systems.36... 

Photoinduced reactions of ethylenes and acetylenes with five-membered heteroarenes continues to be of interest to a number of groups. Mukai and co-workers have shown that 3-aryl-2-isoxazolines (65) undergo [2 r + 2 r] photoaddition to furan and thiophene to give the novel adducts (66) and (67), respectively. The reaction provides a further example of the rarely observed... 

Aliphatic hydrocarbons include three major groups alkanes, alkenes, and alkynes. Alkanes are hydrocarbons in which all the bonds are single bonds, alkenes contain a carbon-carbon double bond, and alkynes contain a carbon-carbon triple bond. Examples of the three classes of aliphatic hydrocarbons are the two-carbon componnds ethane, ethylene, and acetylene. 

Ethylenic and acetylenic alcohols can be converted into ketones or aldehydes by a mild reaction at room temperature, which consists of shaking them in an inert solvent such as petrol, chloroform, benzene, or acetone with a synthetic Mn02 H20.446 The reaction is highly recommended for oxidation of hydroxyl groups in sensitive compounds l-phenyl-2-propyn-l-one is thus obtained in 67.6% yield from l-phenyl-2-propyn-l-ol.447... 

It has been stated that the aromatic compounds differ markedly from the paraffins and the unsaturated hydrocarbons related to ethylene and acetylene. The reactions which take place when benzene and its derivatives are treated with nitric acid, sulphuric acid, or oxidizing agents are characteristic of this group of compounds. Only the higher paraffins react with nitric acid, and in the case of these compounds reaction results to but a slight degree and only after heating for many hours (26). The aromatic hydrocarbons and their substitution-products form well characterized compounds when treated with nitric acid. When benzene is warmed with concentrated nitric acid nitrobenzene is formed —... 

Table 9.10 Examples of Polyimide Structural Adhesives Including the Main Families of Linear Polyimide Precursors as Well as Oligomers Terminated by Ethylenic Double Bonds and Acetylenic Groups...

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