Propiolic acid is the organic compound with the formula HC
2CO
2H. It is the simplest
acetylenic In organic chemistry, the term acetylenic designates
*A doubly unsaturated position (''sp''-hybridized) on a molecular framework, for instance in an alkyne such as acetylene;
*An ethynyl fragment, HC\equivC–, or substituted homologue.
See also ...
carboxylic acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...
. It is a colourless liquid that crystallises to give silky crystals. Near its boiling point, it decomposes.
It is soluble in water and possesses an odor like that of
acetic acid
Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...
.
Preparation
It is prepared commercially by oxidizing
propargyl alcohol
Propargyl alcohol, or 2-propyn-1-ol, is an organic compound with the chemical formula, formula C3H4O. It is the simplest stable Alcohol (chemistry), alcohol containing an alkyne functional group. Propargyl alcohol is a colorless viscous liquid t ...
at a lead electrode.
It can also be prepared by
decarboxylation
Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is t ...
of
acetylenedicarboxylic acid
Acetylenedicarboxylic acid or butynedioic acid is an organic compound (a dicarboxylic acid) with the formula C4H2O4 or . It is a crystalline solid that is soluble in diethyl ether.
The removal of two protons yields the acetylenedicarboxylate di ...
.
:
Reactions and applications
Exposure to
sunlight
Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when t ...
converts it into
trimesic acid
Trimesic acid, also known as benzene-1,3,5-tricarboxylic acid, is an organic compound with the formula C6H3(CO2H)3. It is one of three isomers of benzenetricarboxylic acid. A colorless solid, trimesic acid has some commercial value as a precursor t ...
(benzene-1,3,5-tricarboxylic acid).
[ It undergoes ]bromination
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polyme ...
to give dibromoacrylic acid. With hydrogen chloride
The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride ga ...
it forms chloroacrylic acid. Its ethyl ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are ...
condenses with hydrazine
Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazine ...
to form pyrazolone Pyrazolone is 5-membered heterocycle containing two adjacent nitrogen atoms. It can be viewed as a derivative of pyrazole possessing an additional carbonyl (C=O) group. Compounds containing this functional group are useful commercially in analgesic ...
.[
It forms a characteristic explosive solid upon treatment to its ]aqueous solution
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be re ...
with ammoniacal
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...
silver nitrate
Silver nitrate is an inorganic compound with chemical formula . It is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called ''lunar caustic' ...
.[ An amorphous explosive ]precipitate
In an aqueous solution, precipitation is the process of transforming a dissolved substance into an insoluble solid from a super-saturated solution. The solid formed is called the precipitate. In case of an inorganic chemical reaction leading ...
forms with ammoniacal cuprous chloride
Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear gre ...
.
Propiolates
Propiolates are esters or salts of propiolic acid. Common examples include methyl propiolate and ethyl propiolate.
See also
* Propargyl
* Propargyl alcohol
Propargyl alcohol, or 2-propyn-1-ol, is an organic compound with the chemical formula, formula C3H4O. It is the simplest stable Alcohol (chemistry), alcohol containing an alkyne functional group. Propargyl alcohol is a colorless viscous liquid t ...
References
{{DEFAULTSORT:Propiolic Acid
Carboxylic acids
Alkyne derivatives