Alkynes are aliphatic hydrocarbons that have one or more carbon-carbon triple bonds. The general structure of the alkyne hydrocarbons with one triple bond is CnH2n-2. They are insoluble in water but easily soluble in common organic solvents of low polarity. The features of alkynes in chemical synthesis is due to the acidity of hydrogen atoms bonded to triply bonded carbons as well as the triple bonds themselves. Addition reactions are typical in alkyne reactions halogenation, hydrogenation, hydrohalogenation, hydration, oxidative cleavage, nitrile formation and acidity of terminal alkynes. Polymerisation and substitution reactions are also useful in chemical synthesis.
- Addition Reactions
- Catalytic Hydrogenation by Pt and Pd hydrogenation catalysts to yeild alkanes without isolation of alkene intermediates.
- Catalytic Hydrogenation by Lindlar's catalyst to yeild cis- or trans- alkenes without further reduction to alkanes
- Addition by Electrophilic Reagents
- Addition of halides (chlorine, bromine, iodine) to yield dihalogen substituted alkanes at the solid bond site
- Addition of hydrogen halides (HCl, HBr, HI) to yield monohalogen substituted alkenes or dihalogen substituted alkanes
- Hydration of alkynes to yield ketone products through enol tautomer intermediate stage, whereas the hydration of solid bonds gives alcohol products (exceptionally acetylene yields acetaldehyde ).
- Hydroboration by disiamylborane to yield ketones or aldehydes
- Oxidation cleavages of the triple-bond to give carboxylic acid products with oxidizing agents (potassium permanganate and ozone)
- Nucleophilile Addition by sp-hybrid carbon atoms of the triple-bond render alkynes (nitrile formation)
- Nucleophilile Reduction by solutions of sodium in liquid ammonia to trans-alkenes
The name of all alkynes end in " -yne" adding a prefix to indicate the location of the triple bond in the molecule.
COMPOUND
|
SYNONYM
|
FORMULA
|
CAS RN
|
M.P (C)
|
B.P (C)
|
Ethyne |
Acetylene |
C2H2 |
74-86-2 |
-84.0 |
-28 |
Propyne |
Methyl acetylene |
C3H4
|
74-99-7 |
-103 |
-23 |
1,3-Butadiyne |
Diacetylene |
C4H2 |
460-12-8 |
|
10
|
1-Butyne |
Ethyl acetylene |
C4H6 |
107-00-6 |
-125.7 |
8
|
2-Butyne |
Crotonylene |
C4H6 |
503-17-3 |
-32.2 |
27 |
1,3-Pentadiyne |
|
C5H4 |
4911-55-1 |
|
|
3-Penten-1-yne |
Propenyl acetylene |
C5H6 |
2206-23-7 |
|
|
2-Methyl-1-buten-3-yne |
Isopropenyl acetylene |
C5H6 |
78-80-8 |
-113 |
32 |
1-Penten-3-yne
|
Methyl vinyl acetylene |
C5H6 |
646-05-9 |
|
|
1-Penten-4-yne |
Allyl acetylene |
C5H6 |
871-28-3 |
|
|
2-Pentyne |
Ethyl methyl acetylene |
C5H8 |
627-21-4 |
-109 |
56 |
3-Methyl-1-butyne
|
Isopropyl acetylene |
C5H8 |
598-23-2 |
-89.7 |
26
|
1-Pentyne |
Propyl acetylene |
C5H8 |
627-19-0 |
-106 |
40
|
3-Hexyne |
Diethyl acetylene |
C6H10 |
928-49-4 |
-103 |
81
|
2-Hexyne |
Methyl propyl acetylene |
C6H10 |
764-35-2 |
-89.1 |
84
|
4-Methyl-1-pentyne
|
Isobutyl acetylene
|
C6H10 |
7154-75-8 |
-105 |
61
|
1-Hexyne |
Butyl acetylene |
C6H10 |
693-02-7 |
-131.9 |
71
|
3-Methyl-1-pentyne
|
sec-Butyl acetylene |
C6H10 |
922-59-8 |
|
58
|
4-Methyl-2-pentyne
|
Isopropyl methyl acetylene |
C6H10 |
21020-27-9 |
-110 |
73
|
3,3-Dimethyl-1-butyne
|
tert-Butyl acetylene |
C6H10 |
917-92-0 |
-78.2 |
38 |
1,5-Hexadiyne |
Dipropargyl |
C6H6 |
628-16-0 |
-6 |
86
|
1,4-Hexadiyne |
|
C6H6 |
10420-91-4 |
|
79
|
1,5-Hexadien-3-yne
|
Divinyl acetylene |
C6H6 |
821-08-9 |
|
|
1-Hexen-3-yne
|
Ethyl vinyl acetylene
|
C6H8 |
13721-54-5 |
|
84
|
4-Methyl-2-hexyne
|
sec-Butyl methyl acetylene |
C7H12
|
20198-49-6 |
-108 |
100
|
2-Methyl-3-hexyne
|
Isopropyl ethyl acetylene |
C7H12 |
|
-117 |
95
|
5-Methyl-2-hexyne
|
Isobutyl methyl acetylene |
C7H12 |
53566-37-3 |
-93 |
102
|
3-Ethyl-1-pentyne |
|
C7H12 |
|
|
84 |
1-Heptyne |
n-Pentyl acetylene |
C7H12 |
628-71-7 |
-81 |
100
|
4,4-Dimethyl-2-pentyne
|
tert-Butyl methyl acetylene |
C7H12 |
999-78-0 |
|
83
|
3-Heptyne |
Ethyl propyl acetylene |
C7H12 |
2586-89-2 |
-131 |
107
|
4,4-Dimethyl-1-pentyne
|
Neopentyl acetylene |
C7H12 |
|
-75 |
78
|
2-Heptyne
|
n-Butyl methyl acetylene |
C7H12 |
1119-65-9 |
|
112
|
1,6-Heptadiyne |
|
C7H8 |
2396-63-6 |
|
108
|
1,7-Octadiyne |
|
C8H10 |
871-84-1 |
|
135
|
2,6-Octadiyne |
|
C8H10 |
764-73-8 |
|
|
Cyclooctyne |
|
C8H12 |
1781-78-8 |
|
|
4-Octyne |
Dipropyl acetylene |
C8H14 |
1942-45-6 |
-102.5 |
132
|
1-Octyne |
n-Hexyl acetylene |
C8H14 |
629-05-0 |
-79.3 |
126 |
3-Octyne |
n-Butyl ethyl acetylene |
C8H14 |
15232-76-5 |
-104 |
133
|
2-Octyne
|
n-Pentyl methyl acetylene |
C8H14 |
2809-67-8 |
-61.6 |
138 |
1,8-Nonadiyne |
|
C9H12 |
2396-65-8 |
-21 |
|
Cyclononyne |
|
C9H14 |
6573-52-0 |
|
|
1-Nonyne |
n-Heptyl acetylene |
C9H16 |
3452-09-3 |
-50 |
151 |
3-Nonyne
|
Methyl n-pentyl acetylene |
C9H16 |
20184-89-8 |
|
157 |
2-Nonyne
|
n-Hexyl methyl acetylene |
C9H16 |
19447-29-1 |
|
162
|
4-Nonyne |
n-Butyl propyl acetylene |
C9H16 |
20184-91-2 |
|
|
Cyclodecyne |
|
C10H16 |
3022-41-1 |
|
|
5-Decyne |
Di-n-butyl acetylene |
C10H18 |
1942-46-7 |
-73 |
|
3-Decyne |
Ethyl n-hexyl acetylene |
C10H18 |
2384-85-2 |
|
179
|
1-Decyne |
n-Octyl acetylene |
C10H18 |
764-93-2 |
-44 |
174
|
2,2,5,5-Tetramethyl-3-hexyne
|
Di-tert-butyl acetylene |
C10H18 |
17530-24-4 |
|
|
1-Undecyne |
n-Nonyl acetylene |
C11H20 |
2243-98-3 |
-25 |
195
|
6-Dodecyne |
Di-n-pentyl acetylene |
C12H22 |
6975-99-1 |
|
|
1-Dodecyne |
n-Decyl acetylene |
C12H22 |
765-03-7 |
-19 |
225
|
1-Tridecyne |
n-Undecyl acetylene |
C13H24 |
26186-02-7 |
-5 |
234
|
1-Tetradecyne |
n-Dodecyl acetylene |
C14H26 |
765-10-6 |
|
252
|
1-Pentadecyne |
n-Tridecyl acetylene |
C15H28 |
765-13-9 |
10 |
269
|
1-Hexadecyne
|
n-Tetradecyl acetylene |
C16H30 |
629-74-3 |
25 |
285 |
1-Heptadecyne
|
n-Pentadecyl acetylene |
C17H32 |
26186-00-5 |
22 |
300
|
1-Heptadecyne
|
n-Pentadecyl acetylene |
C17H32 |
26186-00-5 |
22 |
300
|
2-Octadecyne |
|
C18H34 |
|
|
325
|
1-Octadecyne |
|
C18H34 |
629-89-0 |
|
|
1-Nonadecyne |
|
C19H36 |
|
33 |
329
|
1-Eicosyne |
1-Icosyne |
C20H38 |
|
36 |
342 |
|