To understand what alkynes are, we must know what is the meaning of the notion of hydrocarbon. According to Digopaul, this concept refers to the chemical compound that arises when carbon combines with hydrogen.
Within the set of hydrocarbons, we can mention aliphatic hydrocarbons, whose main characteristic is that they lack aromaticity (a property that leads the electrons present in the double bonds to circulate freely between the bonds, granting greater stability to the molecule in compared to what happens when the electrons stay fixed).
From these ideas, we can say that alkynes are aliphatic (that is, non-aromatic) hydrocarbons that have one or more triple bonds between two carbon atoms. The high energy of the triple bond gives them metastability, since they have different states of equilibrium and tend, in the face of external actions, to evolve towards a state of strong equilibrium.
Alkynes often participate in chemical addition reactions, such as hydration, halogenation, and hydrogenation. These hydrocarbons, on the other hand, have a lower density than water, a substance in which they are not soluble. Another physical characteristic of alkynes indicates that, as molecular weight increases, boiling and melting points and density also increase.
In addition to all the above, it is worth knowing another important series of unique data on alkynes such as these:
-When it comes to naming it, we can emphasize that they come to respond to what the CnH2n-2 formula is. That without forgetting that what is done in them is to come to replace the suffix “-ano” of “alc-ano” with the same number of what are carbons by the suffix “-ino”. Thus, for example, instead of propane there is propin and instead of ethane there is ethin.
-They are more polar than alkenes or alkanes can be.
-It should be underlined that, although there are different procedures that can be carried out with these hydrocarbons that concern us, there are some especially significant ones. Among those is, above all, the one that responds to the name of dehydrohalogenation of neighboring dihaloalkanes.
-From the alkynes and through the corresponding process, what is called acetylides can be formed.
-When you want to undertake what is the hydrogenation of alkynes in alkanes, you must establish that a procedure is undertaken in which a leading role is played by what is called alkene.
-In liquid ammonia and with sodium, the aforementioned hydrogenation can also be undertaken.
-Other actions that are also carried out with the alkynes as fundamental axes are, among others, hydroboration and hydration, without forgetting what is called halogenation.
The ethyne, also called acetylene, is an example of alkyne. This gas, which is the easiest alkyne, has one of the highest known combustion temperatures and is used as a source of heat and light.