What is Butyric Acid Definition Formula Reactions and Applications
What is Butyric Acid?
Butyric acid, which is known under the systematic name butanoic acid. It is a carboxylic acid having the structural formula CH3CH2CH2CO2H. It is a colorless and oily liquid that is soluble in ethanol, water, and ether. Isobutyric acid (2-methylpropanoic acid) is an isomer. The salts and esters of butyric acid are referred to as butanoates or butyrates. This acid does not occur widely in nature, whereas its esters are widespread. It is said as a common industrial chemical.
Characteristics of Butyric Acid
The IUPAC name of butanoic acid is the Butyric Acid.
Butyric Acid Structure
[Image will be Uploaded Soon]
Properties of Butyric Acid
Let us discuss more on the physical and chemical properties of butyric acid below:
Physical Properties
Chemical Properties
Butanoic acid reacts with the sodium hydroxide and produces sodium salt of butanoic acid, including water and carbon dioxide.
20NaOH + 21C4H8O2 → 20 NaC4H6O + 4CO2 + 34H2O
The acid on treatment with water produces ether and acetic acid. The chemical equation for this is given as follows.
H2O + C4H8O2 → CH3COOH + C2H6O
Occurrence
Triglycerides of the butyric acid compose 3-4% of butter. Whenever the butter becomes rancid, then the butyric acid is liberated from the glyceride by the process of hydrolysis, by taking the help of citation. It is one of the fatty acid subgroups, which are called short-chain fatty acids. Butyric acid is also a medium-strong acid, which reacts with bases and affects various metals.
Butyric acid is found in plant oils and animal fat, breast milk, bovine milk, butter, parmesan cheese, and an anaerobic fermentation product (like body odor and vomit, including in the colon). Butyric acid somewhat tastes like butter, and it has an unpleasant odor.
Mammals having good scent detection abilities, like dogs, can detect it at 10 parts per billion. On the other side, humans can detect it only in concentrations ranging above 10 parts per million. We can use it as a flavoring agent in food manufacturing.
This acid is one of two primary endogenous agonists of human hydroxycarboxylic acid receptor 2 (HCA2), which is a Gi/o-coupled G protein-coupled receptor.
Butyric acid or the fermentation of butyric acid also exists as the ester octyl butyrate in parsnip (Pastinaca sativa) and the ginkgo tree's seed.
Preparation and Isolation of the Butyric Acid
The oxidation of butyraldehyde can industrially prepare butyric acid.
We can separate it from aqueous solutions by saturation with salts like calcium chloride. The calcium salt, chemically represented as - Ca(C4H7O2)2·H2O, is less soluble in hot water than the cold ones.
Butyric Acid Uses
Butyric acid can be used in the preparation of different butyrate esters. It is also used to form CAB (Cellulose Acetate Butyrate), can be used in a wide range of tools, coatings, and parts, and is more resistant to degradation than that of cellulose acetate. However, Cellulose Acetate Butyrate (CAB) can degrade with exposure to moisture and heat, releasing the butyric acid.
The Low-molecular-weighted esters of the butyric acids, such as methyl butyrate, have mostly pleasant aromas or tastes. Consequently, they are used as perfume and food additives. It can be said as an approved food flavoring in the EU FLAVIS database (as a number - 08.005).
The acid has also been used as a fishing bait additive because of its powerful odor. In many of the commercially available flavors used in the carp baits (Cyprinus carpio) add butyric acid as their ester base. However, it is still unclear whether fish are attracted by the butyric acid itself or to the substances present in it.
However, butyric acid was one of the few organic acids, which is palatable for both bitterling and tench. This substance has also been used as a stink bomb by the Sea Shepherd Conservation Society to disrupt Japanese whaling crews.
Current Status of the Production of Butyric Acid and Future Needs
Butyric acid is produced industrially via a chemical synthesis primarily. This involves butyraldehyde oxidation, obtained from the propylene, derived from crude oil by oxo synthesis. The butyric acid's chemical synthesis is mainly preferred due to its lower production cost and the starting material’s availability. The second method for the preparation of butyric acid is its extraction from butter.
This is possible because its concentration in butter ranges from 2 to 4% but the process involved is expensive and difficult. Thus, it cannot compete with the chemical alternative. A third method is achieved through fermentation. This method is currently more expensive than chemical synthesis; it has garnered more attention because of both a growing consumer desire for natural and organic products, as chemically opposed to synthesized ingredients and a continuous increase in crude oil prices, which is required for the chemical synthesis.
FAQs on Butyric Acid Structure Properties and Uses
1. What is butyric acid?
Butyric acid is a four-carbon carboxylic acid with the molecular formula C4H8O2 and the structural formula C3H7COOH. It is also known as butanoic acid in IUPAC nomenclature.
- It belongs to the homologous series of alkanoic acids.
- It has a strong, rancid smell commonly associated with spoiled butter.
- It occurs naturally in butter, cheese, and as a product of anaerobic fermentation.
2. What is the chemical formula and structure of butyric acid?
The chemical formula of butyric acid is C4H8O2, and its condensed structural formula is CH3CH2CH2COOH.
- It contains a carboxyl group (–COOH) attached to a three-carbon alkyl chain.
- The functional group is responsible for its acidic properties.
- Its structure can be written as CH3–CH2–CH2–COOH.
3. Is butyric acid a strong or weak acid?
Butyric acid is a weak acid because it only partially ionizes in water. Its dissociation in aqueous solution is:
C3H7COOH(aq) ⇌ C3H7COO-(aq) + H+(aq).
- It has a small acid dissociation constant (Ka).
- Like other carboxylic acids, it does not completely release H+ ions.
- Its conjugate base is the butyrate ion (C3H7COO-).
4. How is butyric acid formed?
Butyric acid is formed mainly by anaerobic fermentation of carbohydrates by certain bacteria.
- It is produced by bacteria such as Clostridium species.
- In industry, it can be synthesized by oxidation of butyraldehyde.
- It is also formed naturally during the breakdown of fats in spoiled butter.
5. What are the physical properties of butyric acid?
Butyric acid is a colorless liquid with a strong, unpleasant odor and moderate solubility in water.
- Molar mass: 88.11 g·mol-1
- Boiling point: about 164 °C
- It forms hydrogen bonds due to the –COOH group.
- It is miscible with many organic solvents.
6. What is the difference between butyric acid and acetic acid?
The main difference between butyric acid and acetic acid is their carbon chain length and molecular formula.
- Acetic acid: C2H4O2 (two carbon atoms).
- Butyric acid: C4H8O2 (four carbon atoms).
- Butyric acid has a longer hydrocarbon chain, making it less volatile and more hydrophobic than acetic acid.
7. How does butyric acid react with bases?
Butyric acid reacts with bases in a neutralization reaction to form a salt and water. For example:
C3H7COOH(aq) + NaOH(aq) → C3H7COONa(aq) + H2O(l).
- The product salt is sodium butyrate.
- This reaction follows the general acid–base neutralization pattern.
8. What are the uses of butyric acid in chemistry and industry?
Butyric acid is used in the production of esters, plastics, and flavoring agents.
- Esters like methyl butyrate are used as flavorings and fragrances.
- It is used in manufacturing cellulose acetate butyrate plastics.
- Its salts (butyrates) are studied in biochemistry and microbiology.
9. What is the IUPAC name of butyric acid?
The IUPAC name of butyric acid is butanoic acid.
- The prefix “but-” indicates four carbon atoms.
- The suffix “-anoic acid” denotes a saturated carboxylic acid.
- It follows standard IUPAC nomenclature for alkanoic acids.
10. Can you give an example of esterification involving butyric acid?
Yes, butyric acid reacts with alcohols in an esterification reaction to form esters and water. For example, with ethanol:
C3H7COOH(l) + C2H5OH(l) ⇌ C3H7COOC2H5(l) + H2O(l).
- The product is ethyl butyrate, a fruity-smelling ester.
- This reaction is typically catalyzed by concentrated H2SO4.
