BUTYRIC ACID

CAS NO: 107-92-6
EC NUMBER: 203-532-3

Butyric acid (from Ancient Greek: βούτῡρον, meaning "butter"), also known under the systematic name butanoic acid, is a straight-chain alkyl carboxylic acid with the chemical formula CH3CH2CH2CO2H. 
Butyric acid is an oily, colorless liquid with an unpleasant odor. 
Isobutyric acid (2-methylpropanoic acid) is an isomer. 
Salts and esters of butyric acid are known as butyrates or butanoates. 
The acid does not occur widely in nature, but its esters are widespread. 
Butyric acid is a common industrial chemical and an important component in the mammalian gut.

Butyric acid is a carboxylic acid also classified as a fatty acid. 
Butyric acid exists in two isomeric forms as shown previously, but this entry focuses on n-butyric acid or butanoic acid. 
Butyric acid is a colorless, viscous, rancid-smelling liquid that is present as esters in animal fats and plant oils. 
Butyric acid exists as a glyceride in butter, with a concentration of about 4%; dairy and egg products are a primary source of butyric acid. 
When butter or other food products go rancid, free butyric acid is liberated by hydrolysis, producing the rancid smell. 
Butyric acid also occurs in animal fat and plant oils.

History
Butyric acid was first observed in impure form in 1814 by the French chemist Michel Eugène Chevreul. 
By 1818, he had purified Butyric acid sufficiently to characterize Butyric acid. 
However, Chevreul did not publish his early research on butyric acid; instead, he deposited his findings in manuscript form with the secretary of the Academy of Sciences in Paris, France. 
Henri Braconnot, a French chemist, was also researching the composition of butter and was publishing his findings, and this led to disputes about priority. 
As early as 1815, Chevreul claimed that he had found the substance responsible for the smell of butter.
By 1817, he published some of his findings regarding the properties of butyric acid and named it.
However, Butyric acid was not until 1823 that he presented the properties of butyric acid in detail.
The name butyric acid comes from Ancient Greek: βούτῡρον, meaning "butter", the substance in which Butyric acid was first found. The Latin name butyrum (or buturum) is similar.

Occurrence
Triglycerides of butyric acid compose 3–4% of butter. When butter goes rancid, butyric acid is liberated from the glyceride by hydrolysis.
Butyric acid is one of the fatty acid subgroup called short-chain fatty acids. Butyric acid is a typical carboxylic acid that reacts with bases and affects many metals.
Butyric acid is found in animal fat and plant oils, bovine milk, breast milk, butter, parmesan cheese, body odor, vomit, and as a product of anaerobic fermentation (including in the colon).
Butyric acid has a taste somewhat like butter and an unpleasant odor. 
Mammals with good scent detection abilities, such as dogs, can detect it at 10 parts per billion, whereas humans can detect it only in concentrations above 10 parts per million. 
In food manufacturing, Butyric acid is used as a flavoring agent.

In humans, butyric acid is one of two primary endogenous agonists of human hydroxycarboxylic acid receptor 2 (HCA2), a Gi/o-coupled G protein-coupled receptor.

Butyric acid is present as Butyric acids octyl ester in parsnip (Pastinaca sativa) and in the seed of the ginkgo tree.

Production
Industrial
In industry, butyric acid is produced by hydroformylation from propene and syngas, forming butyraldehyde, which is oxidised to the final product.

H2 + CO + CH3CH=CH2 → CH3CH2CH2CHO → butyric acid
Butyric acid can be separated from aqueous solutions by saturation with salts such as calcium chloride. 
The calcium salt, Ca(C4H7O2)2·H2O, is less soluble in hot water than in cold.

Microbial biosynthesis
Butyrate is produced by several fermentation processes performed by obligate anaerobic bacteria.
This fermentation pathway was discovered by Louis Pasteur in 1861. 
Examples of butyrate-producing species of bacteria:
Clostridium butyricum
Clostridium kluyveri
Clostridium pasteurianum
Faecalibacterium prausnitzii
Fusobacterium nucleatum
Butyrivibrio fibrisolvens
Eubacterium limosum

The pathway starts with the glycolytic cleavage of glucose to two molecules of pyruvate, as happens in most organisms. 
Pyruvate is oxidized into acetyl coenzyme A catalyzed by pyruvate:ferredoxin oxidoreductase. 
Two molecules of carbon dioxide (CO2) and two molecules of elemental hydrogen (H2) are formed as waste products. 
Subsequently, ATP is produced in the last step of the fermentation. Three molecules of ATP are produced for each glucose molecule, a relatively high yield. 
The balanced equation for this fermentation is
C6H12O6 → C4H8O2 + 2 CO2 + 2 H2

Other pathways to butyrate include succinate reduction and crotonate disproportionation.

Several species form acetone and n-butanol in an alternative pathway, which starts as butyrate fermentation. 
Some of these species are:

Clostridium acetobutylicum, the most prominent acetone and butanol producer, used also in industry
Clostridium beijerinckii
Clostridium tetanomorphum
Clostridium aurantibutyricum
These bacteria begin with butyrate fermentation, as described above, but, when the pH drops below 5, they switch into butanol and acetone production to prevent further lowering of the pH. 
Two molecules of butanol are formed for each molecule of acetone.

The change in the pathway occurs after acetoacetyl CoA formation. 
This intermediate then takes two possible pathways:

acetoacetyl CoA → acetoacetate → acetone
acetoacetyl CoA → butyryl CoA → butyraldehyde → butanol

Fermentable fiber sources
Highly-fermentable fiber residues, such as those from resistant starch, oat bran, pectin, and guar are transformed by colonic bacteria into short-chain fatty acids (SCFA) including butyrate, producing more SCFA than less fermentable fibers such as celluloses.
One study found that resistant starch consistently produces more butyrate than other types of dietary fiber.
The production of SCFA from fibers in ruminant animals such as cattle is responsible for the butyrate content of milk and butter.

Fructans are another source of prebiotic soluble dietary fibers which can be digested to produce butyrate.
They are often found in the soluble fibers of foods which are high in sulfur, such as the allium and cruciferous vegetables. 
Sources of fructans include wheat (although some wheat strains such as spelt contain lower amounts), rye, barley, onion, garlic, Jerusalem and globe artichoke, asparagus, beetroot, chicory, dandelion leaves, leek, radicchio, the white part of spring onion, broccoli, brussels sprouts, cabbage, fennel and prebiotics, such as fructooligosaccharides (FOS), oligofructose, and inulin.

Reactions
Butyric acid reacts as a typical carboxylic acid: it can form amide, ester, anhydride, and chloride derivatives.
The latter, butyryl chloride is commonly used as the intermediate to obtain the others.

Uses
Butyric acid is used in the preparation of various butyrate esters. 
Butyric acid is used to produce cellulose acetate butyrate (CAB), which is used in a wide variety of tools, paints, and coatings, and is more resistant to degradation than cellulose acetate.
However, CAB can degrade with exposure to heat and moisture, releasing butyric acid.

Low-molecular-weight esters of butyric acid, such as methyl butyrate, have mostly pleasant aromas or tastes.
As a consequence, they are used as food and perfume additives. 
Butyric acid is an approved food flavoring in the EU FLAVIS database (number 08.005).

Due to its powerful odor, Butyric acid has also been used as a fishing bait additive.
Many of the commercially available flavors used in carp (Cyprinus carpio) baits use butyric acid as their ester base; 
however, Butyric acid is not clear whether fish are attracted by the butyric acid itself or the substances added to Butyric acid. 
Butyric acid was, however, one of the few organic acids shown to be palatable for both tench and bitterling.
he substance has also been used as a stink bomb by Sea Shepherd Conservation Society to disrupt Japanese whaling crews.

Pharmacology

Pharmacodynamics
Butyric acid (pKa 4.82) is fully ionized at physiological pH, so its anion is the material that is mainly relevant in biological systems. 
Butyric acid is one of two primary endogenous agonists of human hydroxycarboxylic acid receptor 2 (HCA2, aka GPR109A), a Gi/o-coupled G protein-coupled receptor (GPCR),

Like other short-chain fatty acids (SCFAs), butyrate is an agonist at the free fatty acid receptors FFAR2 and FFAR3, which function as nutrient sensors that facilitate the homeostatic control of energy balance; 
however, among the group of SCFAs, only butyrate is an agonist of HCA2.
Butyric acid is also an HDAC inhibitor (specifically, HDAC1, HDAC2, HDAC3, and HDAC8), a drug that inhibits the function of histone deacetylase enzymes, thereby favoring an acetylated state of histones in cells.
Histone acetylation loosens the structure of chromatin by reducing the electrostatic attraction between histones and DNA.
In general, Butyric acid is thought that transcription factors will be unable to access regions where histones are tightly associated with DNA (i.e., non-acetylated, e.g., heterochromatin).
Therefore, butyric acid is thought to enhance the transcriptional activity at promoters, which are typically silenced or downregulated due to histone deacetylase activity.

Pharmacokinetics
Butyrate that is produced in the colon through microbial fermentation of dietary fiber is primarily absorbed and metabolized by colonocytes and the liver for the generation of ATP during energy metabolism; 
however, some butyrate is absorbed in the distal colon, which is not connected to the portal vein, thereby allowing for the systemic distribution of butyrate to multiple organ systems through the circulatory system.
Butyrate that has reached systemic circulation can readily cross the blood-brain barrier via monocarboxylate transporters (i.e., certain members of the SLC16A group of transporters).
Other transporters that mediate the passage of butyrate across lipid membranes include SLC5A8 (SMCT1), SLC27A1 (FATP1), and SLC27A4 (FATP4).

Metabolism 
Butyric acid is metabolized by various human XM-ligases (ACSM1, ACSM2B, ASCM3, ACSM4, ACSM5, and ACSM6), also known as butyrate–CoA ligase.
The metabolite produced by this reaction is butyryl–CoA, and is produced as follows:

Adenosine triphosphate + butyric acid + coenzyme A → adenosine monophosphate + pyrophosphate + butyryl-CoA
As a short-chain fatty acid, butyrate is metabolized by mitochondria as an energy (i.e., adenosine triphosphate or ATP) source through fatty acid metabolism.
In particular, it is an important energy source for cells lining the mammalian colon (colonocytes).
Without butyrates, colon cells undergo autophagy (i.e., self-digestion) and die.

In humans, the butyrate precursor tributyrin, which is naturally present in butter, is metabolized by triacylglycerol lipase into dibutyrin and butyrate through the reaction:

Tributyrin + H2O → dibutyrin + butyric acid

Consumer Uses
Butyric acid is used in the following products: air care products, cosmetics and personal care products, biocides (e.g. disinfectants, pest control products), polishes and waxes and washing & cleaning products.
Other release to the environment of Butyric acid is likely to occur from: indoor use as processing aid.

Butyric acid is used in the following products: washing & cleaning products, cosmetics and personal care products, polishes and waxes, laboratory chemicals, coating products, inks and toners and pH regulators and water treatment products. 
Butyric acid is used in the following areas: scientific research and development and health services. 
Other release to the environment of Butyric acid is likely to occur from: indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners).

Butyric acid is used in the following products: washing & cleaning products, pH regulators and water treatment products, laboratory chemicals and polymers.
Butyric acid has an industrial use resulting in manufacture of another substance (use of intermediates).
Butyric acid is used in the following areas: health services and scientific research and development.
Butyric acid is used for the manufacture of: chemicals and food products.
Release to the environment of Butyric acid can occur from industrial use: 
as an intermediate step in further manufacturing of another substance (use of intermediates), in processing aids at industrial sites, as processing aid, for thermoplastic manufacture and in the production of articles.

Butyric Acid is a saturated short-chain fatty acid with a 4-carbon backbone. 
Butyric acid is commonly found in esterified form in animal fats and plant oils.

Butyric acid appears as a colorless liquid with a penetrating and unpleasant odor. 
Flash point 170°F. 
Corrosive to metals and tissue. Density 8.0 lb /gal.

Butyric acid is a straight-chain saturated fatty acid that is butane in which one of the terminal methyl groups has been oxidised to a carboxy group. 
Butyric acid has a role as a Mycoplasma genitalium metabolite and a human urinary metabolite.
Butyric acid is a straight-chain saturated fatty acid and a fatty acid 4:0. 
Butyric acid is a conjugate acid of a butyrate.

Physical Description    
Butyric acid appears as a colorless liquid with a penetrating and unpleasant odor. 
Flash point 170°F. 
Corrosive to metals and tissue. 
Density 8.0 lb /gal.

USE AREAS
-Chemicals in cigarettes, or tobacco related products, or related to the manufacturing of tobacco products
-Byproducts of disinfection processes    
-Contaminants or byproducts in drinking water, such as drugs, pesticides, and radionuclides    
-Drug product, or related to the manufacturing of drugs; modified by veterinary, animal, or pet if indicated by source    
-Related to animals (but non-veterinary) e.g., animal husbandry, farming of animals/animal production, raising of animals for food or fur, animal feed, products for household pets 
-Includes spices, extracts, colorings, flavors, etc added to food for human consumption
-General flavoring agents used in foods, including condiments and seasonings    
-Includes food packaging, paper plates, cutlery, small appliances such as roasters, etc.; does not include facilities that manufacture food    ,
-Beverages for human consumption (e.g., juice, water, alcohol), or related to beverages for human consumption (e.g. machinery for production of beverages, or facilities serving beverages
-Raw materials used in a variety of products and industries

Industry Uses    
-Intermediates
-Processing aids, not otherwise listed

Consumer Uses
-Air care products
-Chemical intermediate / distributor.

Chemical Properties

Butyric acid is a combustible, oily liquid with an unpleasant odor. The Odor Threshold is 0.0001 ppm.
Butyric acid, C3H7COOH, a colorless liquid with an obnoxious odor, occurring in spoiled butter.
Butyric acid miscible with water, alcohol, and ether.
Butyric acid is used in the synthesis of butyrate ester perfume and flavor ingredients and in disinfectants and pharmaceuticals,
Butyric acid (from Greek meaning "butter"), also known under the systematic name butanoic acid, is a carboxylic acid with the structural formula CH3CH2CH2-COOH. 
Salts and esters of butyric acid are known as butyrates or butanoates. 
Butyric acid is found in milk, especially goat, sheep and buffalo's milk, butter, Parmesan cheese, and as a product of anaerobic fermentation (including in the colon and as body odor). 
Butyric acid has an unpleasant smell and acrid taste, with a sweetish aftertaste (similar to ether). 
Butyric acid can be detected by mammals with good scent detection abilities (such as dogs) at 10 ppb, whereas humans can detect it in concentrations above 10 ppm.
Butyric acid was first observed (in impure form) in 1814 by the French chemist Michel Eugène Chevreul. 
By 1818, he had purified it sufficiently to characterize it . 
The name of butyric acid comes from the Latin word for butter, butyrum (or buturum), the substance in which butyric acid was first found.
Butyric acid is a fatty acid occurring in the form of esters in animal fats. 
The triglyceride of butyric acid makes up 3% to 4% of butter. 
When butter goes rancid, butyric acid is liberated from the glyceride by hydrolysis, leading to the unpleasant odor. 
Butyric acid is an important h acid subgroup called short- chain fatty acids. 
Butyric acid is a medium-strong acid that reacts with bases and strong oxidants, and attacks many metals.
The acid is an oily, colorless liquid that is easily soluble in water, ethanol, and ether, and can be separated from an aqueous phase by saturation with salts such as calcium chloride. 
Butyric acid is oxidized to carbon dioxide and acetic acid using potassium dichromate and sulfuric acid, while alkaline potassium permanganate oxidizes it to carbon dioxide. 
The calcium salt, Ca(C4H7O2)2·H2O, is less soluble in hot water than in cold.
Butyric acid has a structural isomer called isobutyric acid (2-methylpropanoic acid).
n-Butyric acid has a persistent, penetrating, rancid, butter-like odor and burning, acid taste.

Occurrence    
Normally occurs in butter as a glyceride. 
Butyric acid has been reported found in the essential oils of citronella Ceylon, Eucalyptus globules, Araucaria cunninghamii, Lippia scaberrima, Monarda fistulosa, cajeput, Heracleum giganteum, lavender, Hedeoma pulegioides, valerian, nutmeg, hops, Pastinaca sativa, Spanish anise and others. 
Butyric acid has been identified in strawberry aroma, apricot, American cranberry, sour cherry, black currants, butter, milk, strawberry jam, cheeses (blue, cheddar, feta, Swiss, Camembert and romano), raspberry, papaya, coffee mutton, beer, rum, bourbon whiskey and cider.

Uses    
Butyric Acid is a fatty acid that is commonly obtained from butter fat. 
Butyric acid has an objectionable odor which limits its uses as a food acid- ulant or antimycotic. 
Butyric acidt is an important chemical reactant in the manufacture of synthetic flavoring, shortening, and other edible food additives. 
in butter fat, the liberation of butyric acid which occurs during hydrolytic rancidity makes the butter fat unusable. 
Butyric acid is used in soy milk-type drinks and candies.

Butyric acid is used in plastics as a raw material for the cellulose acetate butyrate (CAB). 
Other uses of butyric acid are in disinfectants, pharmaceuticals, and feed supplements for plant and animals. 
Butyric acid derivatives play an important role in plant and animal physiology.

Butyric acid is used in the preparation of various butyrate esters. 
Low-molecular-weight esters of butyric acid, such as methyl butyrate, have mostly pleasant aromas or tastes. 
As a consequence, they find use as food and perfume additives. 
Butyric acid is also used as an animal feed supplement, due to the ability to reduce pathogenic bacterial colonization. 
Butyric acid is an approved food flavoring in the EU FLAVIS database (number 08.005).
Due to Butyric acid's powerful odor, it has also been used as a fishing bait additive. 
Many of the commercially available flavors used in carp (Cyprinus carpio) baits use butyric acid as their ester base; 
However, Butyric acid is not clear whether fish are attracted by the butyric acid itself or the substances added to it. 
Butyric acid was, however, one of the few organic acids shown to be palatable for both tench and bitterling. 
Butyric acid has also been used as a stink bomb by Sea Shepherd Conservation Society to disrupt Japanese whaling crews, as well as by anti-abortion protesters to disrupt abortion clinics.

Production Methods    
Butyric Acid is industrially prepared by the fermentation of sugar or starch, brought about by the addition of putrefying cheese, with calcium carbonate added to neutralize the acids formed in the process. 
The butyric fermentation of starch is aided by the direct addition of Bacillus subtilis. 
Salts and esters of the acid are called butyrates or butanoates.
Butyric acid or fermentation butyric acid is also found as a hexyl ester hexyl butyrate in the oil of Heracleum giganteum (a type of hogweed) and as the octyl ester octyl butyrate in parsnip (Pastinaca sativa); 
Butyric Acid has also been noticed in skin flora and perspiration.

Butyric acid is produced by oxidation of butyraldehyde (CH3(CH2)2CHO) or butanol (C4H9OH). 
Butyric Acid can also be formed biologically by the oxidation of sugar and starches using bacteria.

What exactly is butyric acid?
Butyric acid is what’s known as a short-chain fatty acid (SCFA). It’s one of the three most common SCFAs in your gut, along with acetic acid and propionic acid.

These three fatty acids make up between 90 and 95 percentTrusted Source of the SCFAs in your gut.

SCFAs are saturated fatty acids that are created when friendly bacteria break down dietary fiber.

The primary health benefits of butyric acid and other SCFAs are their ability to provide your colon cells with energy. Butyric acid provides your colon cells with about 70 percentTrusted Source of their total energy needs.

Butyric acid goes by several other names, including butyrate and butanoic acid.

What are the benefits of butyric acid?
You’ve likely heard that eating fiber is good for your digestion. Part of the reason why eating more fiber may improve your gut health is because it leads to your colon producing more butyric acid.

What foods is butyric acid found in?
Most of the butyric acid in your body comes from the bacteria in your gut. 
The amount of butyric acid in food is small compared to the amount your gut bacteria produce.

Dietary butyric acid is found in the following foods:
ghee
cow’s milk
butter
sheep’s milk
goat’s milk
breast milk
parmesan cheese
red meat
vegetable oils
sauerkraut

You can findTrusted Source these resistant starches in fruit, whole grains, legumes, and vegetables, like:

artichokes
garlic
onions
asparagus
potatoes
bananas
apples
apricots
carrots
oat bran
You can also find resistant starches in carbs that are cooked then cooled, like:

oats
beans
rice
potatoes

Butyric acid has many important applications in the chemical, food, and pharmaceutical industries. 
The consumption of butyric acid to produce thermoplastics cellulose acetate butyrate is a major use in the chemical industry. 
Glycerol tributyrate and other esters also play an important role in plastic materials. 
Butyric acid is used to supply butter-like notes in food flavours, and its esters are widely used as additives to increase fruit fragrance in the food industry. 
As one of the short-chain fatty acids generated by bacterial fermentation of dietary fibres in the colon, butyric acid is the main energy source for the human body and is also marked as a suppressor of colon cancer. 
Its biological effects have been widely studied, which includes therapeutic effects for hemoglobinopathies, cancer, and gastrointestinal diseases. 
A family of acyloxyalkyl butyrate prodrugs is presently in clinical development. Butyric acid derivatives have also been developed to produce antithyroid and vasoconstrictor drugs and used in anaesthetics.

Butyric acid is a volatile fatty acid that can be used as a flavoring agent. 
Butyric acid  has fruity or cheesy flavor and is mainly found in dairy products.
Butyric acid may be used as a starting material in the preparation of 4-heptanone.

Butyric acid is a colourless liquid that is soluble in water. 
Scientifically speaking, its structure is four-carbon fatty acids with the molecular formula C4H8O2 or CH3CH2CH2COOH. 
Butyric acid has other chemical names, including butanoic acid, n-butyric acid, n-butanoic acid and propylformic acid.
Along with acetic and propionic acids, they account for approximately 83% of the short-chain fatty acids in the human colon.

On its own, Butyric acid has an unpleasant smell and bitter, pungent taste, with a somewhat sweet aftertaste. 
It occurs as esters in animal fats and plant oils.
What’s an ester? 
An ester is an organic compound that reacts with water to produce alcohols and organic or inorganic acids. 
Esters derived from carboxylic acids like butyric acid are the most common type of esters.

Butyric acid is generated in the large intestine together with other short-chain fatty acids from the fermentation of dietary carbohydrates, specific prebiotics like resistant starches, fructooligosaccharides and other dietary fibre. 

The names “butyric acid” and “butyrate” are commonly used interchangeably even in scientific articles and studies. 
Technically, they have slightly different structures, but they’re still very similar. 
Butyrate or butanoate is the traditional name for the conjugate base of butyric acid. 
Put simply, butyrate is almost identical to butyric acid, but it just has one less proton. 
Judging by scientific studies, they appear to be pretty much identical in their health benefits.

Health Benefits
Weight Loss
Butyric has gained popularity for its ability to possibly help people shed unwanted pounds. 
Scientific evidence has shown that people who are obese (as well as people who have type II diabetes) have a different composition of gut bacteria. 
Short-chain fatty acids are believed to play a positive role along with probiotics in preventing metabolic syndrome, which almost always includes abdominal obesity. 
Short-chain fatty acids like butyric acid help regulate the balance between fatty acid synthesis and the breakdown of fats. 
In a 2007 animal study, after five weeks of treatment with Butyric acid, obese mice lost 10.2% of their original body weight, and body fat was reduced by 10%. 
Butyric acid was also shown to improve insulin sensitivity, which helps guard against weight gain.
Most of the evidence for linking Butyric acid supplementation specifically to weight loss is based on animal research so far, but it does show positive effects in treating obesity naturally.

Butyric acid, a four-carbon fatty acid, is formed in the human colon by bacterial fermentation of carbohydrates (including dietary fiber), and putatively suppresses colorectal cancer (CRC). 
Butyrate has diverse and apparently paradoxical effects on cellular proliferation, apoptosis and differentiation that may be either pro-neoplastic or anti-neoplastic, depending upon factors such as the level of exposure, availability of other metabolic substrate and the intracellular milieu. 
In humans, the relationship between luminal butyrate exposure and CRC has been examined only indirectly in case-control studies, by measuring fecal butyrate concentrations, although this may not accurately reflect effective butyrate exposure during carcinogenesis. 
Perhaps not surprisingly, results of these investigations have been mutually contradictory. The direct effect of butyrate on tumorigenesis has been assessed in a no. of in vivo animal models, which have also yielded conflicting results. 
In part, this may be explained by methodology: differences in the amount and route of butyrate administration, which are likely to significantly influence delivery of butyrate to the distal colon. 
Butyric acid is a carboxylic acid found in rancid butter, parmesan cheese, and vomit, and has an unpleasant odor and acrid taste, with a sweetish aftertaste (similar to ether). 
Butyric acid is a fatty acid occurring in the form of esters in animal fats and plant oils. 
Interestingly, low-molecular-weight esters of butyric acid, such as methyl butyrate, have mostly pleasant aromas or tastes. 
As a consequence, they find use as food and perfume additives. Butyrate is produced as end-product of a fermentation process solely performed by obligate anaerobic bacteria.

Butyric acid (CH3CH2CH2CO2H), also called butanoic acid, is a fatty acid occurring in the form of esters in animal fats and plant oils. 
As a glyceride (an ester-containing acid and glycerol), it makes up 3–4 %of butter; 
the disagreeable odour of rancid butter is that of hydrolysis of the butyric acid glyceride. 
The acid is of considerable commercial importance as a raw material in the manufacture of esters of lower alcohols for use as flavouring agents; 
Butyric acid's anhydride is used to make cellulose butyrate, a useful plastic. 
Butyric acid is manufactured by catalyzed air oxidation of butanal (butyraldehyde).
Butyric acid is a colourless liquid, soluble in water and miscible with common organic solvents; 
Butyric acid freezes at −7.9 °C (17.8 °F) and boils at 163.5 °C (326.3 °F). 
An isomer, 2-methylpropanoic (isobutyric) acid, (CH3)2CHCO2H, is found both in the free state and as its ethyl ester in a few plant oils.
Although Butyric acid is commercially less important than butyric acid, Butyric acid is generally similar to butyric acid; 
Butyric acid freezes at −46.1 °C (−51 °F) and boils at 153.2 °C (307.8 °F).

IUPAC NAMES:
butane acid
BUTANOIC ACID
Butanoic acid
butanoic acid
Buttersäure
C&L Inventory
Butyric Acid
Butyric acid
butyric acid
butyric acid
butyric acid, Butanoic acid
buytyric acid
n butyric acid
n-Butyric acid

SYNONYMS
butyric acid
butanoic acid
107-92-6
n-Butyric acid
n-Butanoic acid
propylformic acid
ethylacetic acid
Butanic acid
1-propanecarboxylic acid
1-Butyric acid
Buttersaeure
butanoate
Butyric acid (natural)
Kyselina maselna
Propanecarboxylic acid
Buttersaeure [German]
1-butanoic acid
FEMA Number 2221
Kyselina maselna [Czech]
MFCD00002814
FEMA No. 2221
CCRIS 6552
HSDB 940
butoic acid
2-butanoate
NSC 8415
UNII-40UIR9Q29H
UN2820
AI3-15306
C4:0
CH3-[CH2]2-COOH
40UIR9Q29H
CHEBI:30772
NSC8415
butanate
propylformate
Butyrate sodium
1-butanoate
propanecarboxylate
1-butyrate
Butyric acid [UN2820] [Corrosive]
Sodium n-butyrate
1-propanecarboxylate
DSSTox_CID_1515
n-Butyric acid, 99+%
DSSTox_RID_76192
DSSTox_GSID_21515
67254-79-9
BUA
acide butyrique
CAS-107-92-6
Butyric Acid (Normal)
EINECS 203-532-3
BRN 0906770
sodium-butyrate
acide butanoique
Fatty acids
Honey robber
ethyl acetic acid
1ugp
3umq
butanoic acid, 4
Nat. Butyric Acid
Fatty Acid,Vegetable
TNFa + NaBut
Butyrate, sodium salt
Butyric acid [UN2820] [Corrosive]
156779-02-1
BUTYRIC_ACID
n-C3H7COOH
TNFa + Sodium Butyrate
Butyric acid, >=99%
bmse000402
EC 203-532-3
NATURAL BUTYRIC ACID
NCIMech_000707
WLN: QV3
ACMC-1C12J
4-02-00-00779 (Beilstein Handbook Reference)
CCCC([O])=O
CHEMBL14227
Butyric acid, >=99%, FG
BUTYRIC-3,3-D2 ACID
Butyric acid, analytical standard
N-butyric acid, ethyl acetic acid
ZINC895132
BUTYRIC-1,2-13C2 ACID8
MCULE-4116382006
BUTYRIC-3,3,4,4,4-D5 ACID
Butyric acid, natural, >=99%, FCC, FG
V2319
Butyric acid 1000 microg/mL in Acetonitrile
Butyric acid, SAJ special grade, >=99.5%