3-Hydroxypropionic acid is a
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 ...
, specifically a
beta hydroxy acid
A beta hydroxy acid or β-hydroxy acid (BHA) is an organic compound that contains a carboxylic acid functional group and hydroxy functional group separated by ''two'' carbon atoms. They are closely related to alpha hydroxy acids, in which the tw ...
. It is an acidic viscous liquid with a
pKa of 4.5.
It is very soluble in water, soluble in
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...
and
diethyl ether
Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liq ...
. Upon distillation, it
dehydrates to form
acrylic acid
Acrylic acid (IUPAC: propenoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a ...
, and is occasionally called hydracrylic acid
3-Hydroxypropionic acid is used in the industrial production of various chemicals such as
acrylate
Acrylates (IUPAC: prop-2-enoates) are the salts, esters, and conjugate bases of acrylic acid. The acrylate ion is the anion C H2=CHC OO−. Often, acrylate refers to esters of acrylic acid, the most common member being methyl acrylate. These acry ...
s.
Synthesis
3-Hydroxypropionic acid can be obtained by base-induced hydration of acrylic acid followed by reacidification. Another synthesis involves cyanation of ethylene chlorohydrin followed by hydrolysis of the resulting nitrile. Hydrolysis of
propiolactone Propiolactone may refer to either of two isomeric chemical compounds:
* Alpha-Propiolactone (α-Propiolactone)
* Beta-Propiolactone
β-Propiolactone is an organic compound of the lactone family, with a four-membered ring. It is a colorless liq ...
is yet another route.
Potential applications
The
polyester
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natural ...
poly(3-hydroxypropionic acid) is a
biodegradable polymer
Biodegradable polymers are a special class of polymer that breaks down after its intended purpose by bacterial decomposition process to result in natural byproducts such as gases ( CO2, N2), water, biomass, and inorganic salts. These polymers ar ...
. The method combines the high-molecular weight and control aspects of
ring-opening polymerization
In polymer chemistry, ring-opening polymerization (ROP) is a form of chain-growth polymerization, in which the terminus of a polymer chain attacks cyclic monomers to form a longer polymer (see figure). The reactive center can be radical, anion ...
with the commercial availability of the beta hydroxy acid, 3-hydroxypropionic acid which is abbreviated as 3-HP. Since 3-HPA can be derived from biological sources, the resulting material, poly(3-hydroxypropionic acid) or P(3-HPA), is biorenewable.
Genetically encoded 3-hydroxypropionic acid inducible system
3-Hydroxypropionic acid can be produced by engineered
microbes
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
.
A genetically encoded 3-hydroxypropionic acid inducible system has been characterized in bacteria demonstrating that such system in combination with fluorescent reporter protein can be utilized as a biosensor to measure intracellular and extracellular 3-HP concentrations by fluorescence output.
See also
*
Lactic acid
Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natu ...
(2-hydroxypropanoic acid)
* listed as hydracrylic acid in the Merck index, 12th Edition
References
External links
*
{{DEFAULTSORT:Hydroxypropanoic acid, 3-
Beta hydroxy acids
Propionic acids