STEARIC ACID

STEARIC ACID

CAS No. : 57-11-4
EC No. : 200-313-4

Stearic acid is a saturated fatty acid represented by the formula CH₃ (CH₂) ₁₆COOH. In fats and oils obtained from many animals and plants, mostly glyceride is found in the form of stearin. Stearic acid and its compounds, especially its salts, are of commercial importance. Long chain alcohol esters are known as wax.

Synonyms:
stearic acid; Octadecanoic acid; 57-11-4; Stearic acid 1843;  Stearic acid 1842;  Stearic acid 1865; Stearophanic acid; n-Octadecanoic acid; stearic acid; Octadecanoic acid; 57-11-4; Stearophanic acid; n-Octadecanoic acid; Cetylacetic acid; Pearl stearic; Stearex Beads; Octadecansaeure; Stearinsaeure; Vanicol; 1-Heptadecanecarboxylic acid; Century 1240; Industrene R; Glycon DP; Glycon TP; Humko Industrene R; Dar-chem 14; Formula 300; Hydrofol 1895; Hystrene 9718; Hydrofol Acid 150; Glycon S-80; Glycon S-90; Hydrofol acid 1655; Hydrofol acid 1855; Tegostearic 254; Tegostearic 255; Tegostearic 272; Hystrene 80; octadecoic acid; Industrene 5016; Hystrene S-97; Hystrene T-70; Emersol 120; Emersol 132; Hystrene 4516; Hystrene 5016; Hystrene 7018; Groco 54; Groco 55; Groco 55L; Groco 58; Groco 59; Glycon S-70; Industrene 8718; Industrene 9018; Kam 1000; Emersol 150; Steric acid; Neo-Fat 18-53; Neo-Fat 18-54; Neo-Fat 18-59; Neo-Fat 18; Acidum stearinicul; Caswell No. 801D; HY-Phi 1199; HY-Phi 1205; HY-Phi 1303; HY-Phi 1401; Neo-Fat 18-S; C18:0; Kam 2000; Kam 3000; Oktadekansaeure; Neo-Fat 18-55; Neo-Fat 18-61; acide stearique; FEMA No. 3035; PD 185; acide octadecanoique; Stearic acid, pure; Octadecanoate; NAA 173; Hydrofol Acid 150 (VAN); CCRIS 2305; Prifac 2918; HSDB 2000; Vis-Plus; Barolub FTA; UNII-4ELV7Z65AP; NSC 25956; Haimaric MKH(R); Isostearic acid EX; EPA Pesticide Chemical Code 079082; Stearic Acid Cherry; Edenor C18; Emersol 871; Emersol 875; Prisorine 3501; Prisorine 3502; Prisorine 3508; Stearic acid (TN); CH3-[CH2]16-COOH; Loxiol G 20; Century 1210; Century 1220; Century 1230; Emersol 6349; AI3-00909; Emery 875D; Lunac S 20; Lunac S 40; WO 2 (fatty acid); Emery 871; Hydrofol Acid 1895; Unimac 5680; EINECS 200-313-4; MFCD00002752; BRN 0608585; Adeka Fatty Acid SA 910; EINECS 250-178-0; Stearic acid, 97%; 124-26-5 (amide) 57-11-4 (free base); DSSTox_GSID_21642; Lunac; Stearic Acid (Powder/Beads/Flakes); Fatty acids, C16-20; CAS-57-11-4; Emersol 153NF; C-Lube 10; Stearic acid [JAN:NF]; Stearic acid [USAN:JAN]; Stearophanate; Promulsin; Stearex; Tsubaki; n-Octadecanoate; Bassinic acid; Lactaric acid; Agar powder; Talgic acid; 1hmr; 1hmt; 4fnn; Kiri stearic acid; Edenor FHTI; Lunac YA; n-Octadecylic acid; Stearic acid, CP; EINECS 273-087-8; F 3 (lubricant); Industrene 4518; Nonsoul SK 1; Pristerene 4900; Pristerene 4904; Pristerene 4963; Pristerene 9429; Pristerene 9559; Hystrene S 97; Hystrene T 70; Edenor ST 1; Sunfat 18S; Emersol 153; Selosol 920; Industrene 5016K; Stearic Acid 110; Stearic Acid 120; Stearic Acid 420; Hystrene 9718NF; Kortacid 1895; Radiacid 0427; Edenor ST 20; Lunac 30; Serfax MT 90; Stearic acid_ravikumar; Unister NAA 180; Century 1224; Edenor HT-JG 60; Lunac S 90KC; Stearic acid (8CI); Stearic acid, puriss.; Hystrene 7018 FG; Hystrene 9718NFFG; Lunac S 30; Lunac S 50; Lunac S 90; Lunac S 98; 3v2p; 1-Heptadecanecarboxylate; Industrene 7018 FG; Stearic Acid NF Powder; AFCO-Chem B 65; Stearic Acid - 65%; Stearic Acid - 70%; Stearic Acid 153 NF; Heptadecanecarboxylic acid; Stearic Acid & Glycerin; Edenor C 18/98; S 300 (fatty acid); Octadecanoic acid (9CI); Stearic acid, >=98%; ACMC-1AR8K; SCHEMBL659; Hystrene 9718 NF FG; SA 400 (fatty acid); bmse000485; Stearic Acid, High Purity; EC 200-313-4; Emery 400 (Salt/Mix); Stearic acid 57-11-; Stearic acid (JP15/NF); Stearic acid (JP17/NF)
GENERAL DESCRIPTION: Fatty Acids are aliphatic carboxylic acid with varying hydrocarbon lengths at one end of the chain joined to terminal carboxyl (-COOH) group at the other end. The general formula is R-(CH2)n-COOH. Fatty acids are predominantly unbranched and those with even numbers of carbon atoms between 12 and 22 carbons long react with glycerol to form lipids (fat-soluble components of living cells) in plants, animals, and microorganisms. Fatty acids all have common names respectively lauric (C12), myrIstic (C14), palmitic (C16), stearic (C18), oleic (C18, unsaturated), and linoleic (C18, polyunsaturated) acids. The saturated fatty acids have no double bonds, while oleic acid is an unsaturated fatty acid has one double bond (also described as olefinic) and polyunsaturated fatty acids like linolenic acid contain two or more double bonds. Lauric acid (also called Dodecanoic acid) is the main acid in coconut oil (45 - 50 percent) and palm kernel oil (45 - 55 percent). Nutmeg butter is rich in myristic acid (also called Tetradecanoic acid ) which constitutes 60-75 percent of the fatty-acid content. Palmitic acid(also called Hexadecylic acid ) constitutes between 20 and 30 percent of most animal fats and is also an important constituent of most vegetable fats (35 - 45 percent of palm oil). Stearic acid (also called Octadecanoic Acid)  is nature's most common long-chain fatty acids, derived from animal and vegetable fats. It is widely used as a lubricant and as an additive in industrial preparations. It is used in the manufacture of metallic stearates, pharmaceuticals, soaps, cosmetics, and food packaging. It is also used as a softener, accelerator activator and dispersing agent in rubbers. Oleic acid (systematic chemical name is cis-octadec-9-enoic acid) is the most abundant of the unsaturated fatty acids in nature. Stearic Acid is widely used as a lubricant and as an additive in industrial preparations. It is used in the manufacture of metallic stearates, pharmaceuticals, soaps, cosmetics, and food packaging. It is also used as a softener, accelerator activator and dispersing agent in rubbers.
In nature stearic acid occurs primarily as a mixed triglyceride, or fat, with other long-chain acids and as an ester of a fatty alcohol. It is much more abundant in animal fat than in vegetable fat; lard and tallow often contain up to 30 percent stearic acid.
Alkaline hydrolysis, or saponification, of fats yields soaps, which are the sodium or potassium salts of fatty acids; pure stearic acid is obtained with difficulty from such a mixture by crystallization, vacuum distillation, or chromatography of the acids or suitable derivatives. The pure acid undergoes chemical reactions typical of carboxylic acids. It is a colourless, waxy solid that is almost insoluble in water.

Stearic acid is one of several major long-chain fatty acids comprising oils and fats. It is presented in animal fats, oil and some kinds of vegetable oils as wellin the form of glycerides. These oils, after hydrolysis, produce the stearic acid. 
Stearic acid is a fatty acid widely existing in nature and has the general chemical properties of carboxylic acids. Almost all kinds of fat and oil contain certain amount of stearic acid with the content in the animal fats being relative high. For example, the content in the butter can reach up to 24% while the content in vegetable oil is relative low with the value in tea oil being 0.8% and the oil in palm being 6%. However, the content in cocoa can reach as high as 34%. 
There are two major approaches for industrial production of stearic acid, namely fractionation and compression method. Add decomposition agent to the hydrogenated oil, and then hydrolyze to give the crude fatty acid, further go through washing with water, distillation, bleaching to obtain the finished products with glycerol as the byproduct. 
Most domestic manufacturers use animal fat for production. Some kinds of production technology will result in the incompletion of the distillation of fatty acid which produce stimulating odor at the time of the plastic processing and high temperatures. Although these odor is of no toxic but they will have certain effect on the working conditions and the natural environment. Most imported form of stearic acid takes vegetable oil as the raw materials, the production processes are more advanced; the produced stearic acid is of stable performance, good lubrication property and less odor in the application. 
Stearic acid is mainly used for the production of stearates such as sodium stearate, magnesium stearate, calcium stearate, lead stearate, aluminum stearate, cadmium stearate, iron stearate, and potassium stearate. The sodium or potassium salt of stearic acid is the component of soap. Although sodium stearate has a less decontamination ability than sodium palmitate, but its presence may increase the hardness of soap.
Take butter as raw material, go through sulfuric acid or pressurized method for decomposition. The free fatty acids was first subject to water pressure method for removing the palmitic acid and oleic acid at 30~40 ℃, and then dissolved in ethanol, followed by addition of barium acetate or magnesium acetate which precipitates stearate. Then further add dilute sulfuric acid to get the free stearate acid, filter and take it, and re-crystallize in ethanol to obtain the pure stearic acid.
Pure product appears as white shiny soft small pieces. It is slightly soluble in water, soluble in alcohol, acetone, easily soluble in benzene, chloroform, ether, carbon tetrachloride, carbon disulfide, amyl acetate and toluene.
Commercial fats produced by organic processes in plants are palm, coconut, palm kernel, sunflower,  soybean, and other oils. Their main components are triolein and triglyceryl esters of stearic (C18), palmitic (C16), myristic(C14), lauric (C12), oleic (C18:1), and other fatty acids. Tallow is a refined hard fat extracted from fatty deposits of animals, especially from suet (fatty tissues around the kidneys of cattle and sheep). The molecules of most natural fatty acids have an even number of carbon chains due to the linkage together by ester units. Analogous compounds of odd numbers carbon chain fatty acids can be made synthetically. All fats are insoluble in water and have lighter weight than water. Industrial fats can be sub-classified as fat, grease or oil depending on melting point. Fats that are liquid at room temperature are referred to oil. Grease has a higher initial viscosity than oil. It is used as a lubricant. The organic processes to convert fats to fatty acids (or esters) and glycerol is called oleochemistry. Fatty acids and glycerol are produced by hydrolysis (addition reaction of water molecule with cleavage of parent molecules) of the triglycerides. Fatty esters are produced by esterification reaction. Coconut or palm oils are better source to get saturated fatty acids than sunflower, soybean or rapeseed oils which have more unsaturated fatty acids composition of triglycerides. Tall oil fatty acid (TOFA) is a low cost unsaturated fatty acid (oleic acid) and is a source of low boiling point fatty acids. It is an alternative to tallow fatty acid in soap applications. Generally, commercial coconut fatty acid has carbon chain composition of; C10 (5% max) + C12 (45 - 55%) + C14 (20 - 25%) + C16 (10 - 15 %) + C18 (10 - 15% max, including unsaturated fatty acids). Fats are used to make soap, food products, cosmetics, and candles, and lubricants. They are wisely used in producing synthetic surfactants.
Stearic acid (/ˈstɪərɪk/ STEER-ik, /stiˈærɪk/ stee-ARR-ik) is a saturated fatty acid with an 18-carbon chain Its name comes from the Greek word στέαρ "stéar", which means tallow. The salts and esters of stearic acid are called stearates. As its ester, stearic acid is one of the most common saturated fatty acids found in nature following palmitic acid.The triglyceride derived from three molecules of stearic acid is called stearin.
Production
Stearic acid is obtained from fats and oils by the saponification of the triglycerides using hot water (about 100 °C). The resulting mixture is then distilled.Commercial stearic acid is often a mixture of stearic and palmitic acids, although purified stearic acid is available.
Fats and oils rich in stearic acid are more abundant in animal fat (up to 30%) than in vegetable fat (typically <5%). The important exceptions are the foods cocoa butter (34%)and shea butter, where the stearic acid content (as a triglyceride) is 28–45%.
In terms of its biosynthesis, stearic acid is produced from carbohydrates via the fatty acid synthesis machinery wherein acetyl-CoA contributes two-carbon building blocks.
Stearic acid (trivial name), cetlacetic or n-octadecanoic acid (eng. Octadecanoic acid), monobasic carboxylic acid of aliphatic series, readily soluble in diethyl ether at room temperature and has the form of colorless crystals insoluble in water. Stearic acid is a saturated fatty acid, one of the most abundant fatty acids in nature. It is found in lipids in the form of glycerides, mainly triglycerides (fats) of animal origin, also in most animal fats and to a lesser extent in many vegetable oils. The molecular weight is 248.48 g / mol, the density is 0.94 g / ml. Stearic acid has a melting point of 69.6 ° C and a boiling point of 376.1 ° C.

Application
Stearic acid is part of pharmaceuticals; used as a component of greases.
In cosmetics, stearic acid is used as a mixture stabilizer and emulsifier in the production of cosmetic creams and lotions, while it is also used as a thickener in soap making, which makes soap hard and matte. Stearic acid salt, which has good cleaning properties, is generally used in soap production.
Stearic acid is used in the food industry as a food additive - emulsifier, foam stabilizer, polishing agent and antifoam with the index "E570 Fatty acids". Stearic acid is also used in wax and rubber production (to provide greater flexibility and homogeneity), grease production, and stearin (often mixed with palmitic and / or oleic acids).
Stearic acid is widely used in cosmetics, plastics plasticizers, mold release agents, stabilizers, surfactants, rubber vulcanization accelerator, waterproof agent, polishing agent, metal soap, metal mineral flotation agents, softeners and pharmaceuticals as well as other organic chemicals. Stearic acid can also be used as the solvents of oil-soluble paint, crayons lubrication agent, stencil lighting agent and the emulsifier of stearic acid glyceride. 
Stearic acid can also be widely used in the manufacturing of PVC pipe, sheet material, profiles and film and is the PVC heat stabilizers with good lubricity and excellent stability against light and heat. In the application of polyvinyl chloride pipe, stearic acid helps prevent the "coke" during the processing and is effective heat stabilizer during PVC film processing while also preventing the discoloration of the finished film discoloration caused by exposure.
Stearic acid has become the additive for lubrication, plasticization and stabilization of the filled masterbatch. Stearic acid can effectively improve the coating activating effect of inorganic powder and increase the flow rate of materials. When there is demand for a large flow rate of the melt for material with inorganic powder accounting for the most part, an appropriate increase in the content of stearic acid can significantly increase the melt flow rate of material. However, the amount of stearic acid used in filled masterbatch also have threshold with its amount being controlled in about 1% of the total mass. If the added amount is over-excessive, it will not only cause the decrease of the quality and the performance of plastic products but also generate sticky substance in the die lip location of the manufacturing equipment of the plastic products, affecting the production efficiency and product quality.
The mono-or multi-alcohol ester of stearic acid can be used as cosmetics, nonionic surfactants and plasticizers. Its alkali metal salt can be dissolved in water and is a major component of soap. Other kinds of salts can be used as waterproofing agents, lubricants, bactericides, coating additives and PVC stabilizers.
Production method
There are two major approaches for industrial production of stearic acid, namely fractionation and compression method. Add decomposition agent to the hydrogenated oil, and then hydrolyze to give the crude fatty acid, further go through washing with water, distillation, bleaching to obtain the finished products with glycerol as the byproduct. 
Compression method takes animal oil as raw material. Have animal oil subject to hydrolysis in the catalysis of zinc oxide at pressure of 1.17~1.47 MPa, further go through pickling, washing, distillation, cooling, freezing, press for removal of oleic acid to get the finished products.
Heat the cotton seed oil, rice bran oil, or soybean oil in the presence of a hydrolyzing agent under normal pressure to boiling with hydrolysis of 1.5 h and harden to saturated fatty acid. Oleic acid hydrogenation;
Use the C10~C20 and C18~C20 fraction of the synthetic fatty acid as raw materials, go through melting, pickling (with 1% sulfuric acid) mold, pressing, melting, pickling, dehydrating and crystallization to obtain it. 
It can be obtained through the low-temperature segment separation of the mixed fatty acid.
It can also be made through the hydrogenation of oleic acid.

Uses
In general, the applications of stearic acid exploit its bifunctional character, with a polar head group that can be attached to metal cations and a nonpolar chain that confers solubility in organic solvents. The combination leads to uses as a surfactant and softening agent. Stearic acid undergoes the typical reactions of saturated carboxylic acids, a notable one being Pharmaceutic aid (emulsion adjunct); pharmaceutic aid (tablet and/or capsule lubricant). stearic acid is an emulsifier and thickening agent found in many vegetable fats. Stearic acid is the main ingredient used in making bar soaps and lubricants. It occurs naturally in butter acids, tallow, cascarilla bark, and in other animal fats and oils. Stearic acid may cause allergic reactions in people with sensitive skin and is considered somewhat comedogenic.reduction to stearyl alcohol, and esterification with a range of alcohols. This is used in a large range of manufactures, from simple to complex electronic devices.
Stearic acid is incompatible with strong oxidizers and strong bases. Stearic acid is also incompatible with reducing agents.
It can be used as natural rubber, synthetic rubber (except butyl rubber) and latex curing active agent. It can also be used as raw material of plastic plasticizer and stabilizer. Medicine: it can be used for the preparation of ointments, suppositories, etc., as well as being used in the manufacture of cosmetics, candles, waterproof agent and polishing agent. The product can be used as a lubricant, defoamers and food additives in the food industry as well as the raw materials of glycerol stearate, stearic acid sorbitol anhydride esters and sucrose esters. 
It can also be used as standard reference product for gas analysis as well as the preparation of soap, cosmetics, pharmaceuticals and other organic chemicals.
As food additive
Stearic acid (E number E570) is found in some foods.
Soaps, cosmetics, detergents
Stearic acid is mainly used in the production of detergents, soaps, and cosmetics such as shampoos and shaving cream products. Soaps are not made directly from stearic acid, but indirectly by saponification of triglycerides consisting of stearic acid esters. Esters of stearic acid with ethylene glycol, glycol stearate, and glycol distearate are used to produce a pearly effect in shampoos, soaps, and other cosmetic products. They are added to the product in molten form and allowed to crystallize under controlled conditions. Detergents are obtained from amides and quaternary alkylammonium derivatives of stearic acid.
Lubricants, softening and release agents
In view of the soft texture of the sodium salt, which is the main component of soap, other salts are also useful for their lubricating properties. Lithium stearate is an important component of grease. The stearate salts of zinc, calcium, cadmium, and lead are used to soften PVC. Stearic acid is used along with castor oil for preparing softeners in textile sizing. They are heated and mixed with caustic potash or caustic soda. Related salts are also commonly used as release agents, e.g. in the production of automobile tires. As an example, it can be used to make castings from a plaster piece mold or waste mold, and to make a mold from a shellacked clay original. In this use, powdered stearic acid is mixed in water and the suspension is brushed onto the surface to be parted after casting. This reacts with the calcium in the plaster to form a thin layer of calcium stearate, which functions as a release agent.[15]
When reacted with zinc it forms zinc stearate, which is used as a lubricant for playing cards (fanning powder) to ensure a smooth motion when fanning. Stearic acid is a common lubricant during injection molding and pressing of ceramic powders.[16] It is also used as a mold release for foam latex that is baked in stone molds.
Niche uses
Being inexpensive, nontoxic, and fairly inert, stearic acid finds many niche applications. Stearic acid is used as a negative plate additive in the manufacture of lead-acid batteries. It is added at the rate of 0.6 g per kg of the oxide while preparing the paste. It is believed to enhance the hydrophobicity of the negative plate, particularly during dry-charging process. It also reduces the extension of oxidation of the freshly formed lead (negative active material) when the plates are kept for drying in the open atmosphere after the process of tank formation. As a consequence, the charging time of a dry uncharged battery during initial filling and charging (IFC) is comparatively lower, as compared to a battery assembled with plates which do not contain stearic acid additive. Fatty acids are classic components of candle-making. Stearic acid is used along with simple sugar or corn syrup as a hardener in candies. In fireworks, stearic acid is often used to coat metal powders such as aluminium and iron. This prevents oxidation, allowing compositions to be stored for a longer period of time.
Metabolism
An isotope labeling study in humans concluded that the fraction of dietary stearic acid that oxidatively desaturates to oleic acid is 2.4 times higher than the fraction of palmitic acid analogously converted to palmitoleic acid. Also, stearic acid is less likely to be incorporated into cholesterol esters. In epidemiologic and clinical studies, stearic acid was found to be associated with lowered LDL cholesterol in comparison with other saturated fatty acids.
Salts and esters
Stearates are the salts or esters of stearic acid. The conjugate base of stearic acid, C17H35COO−, is also known as the stearate anion.
Examples
Salts, Calcium stearate, Lithium stearate, Magnesium stearate, Sodium stearate, Zinc stearate, Esters, Estradiol stearate, Glycol stearate, Stearin, Testosterone stearate.
Properties
Chemical formula C18H36O2
Molar mass 284.484 g·mol−1
Appearance White solid
Odor Pungent, oily
Density 0.9408 g/cm3 (20 °C)[2]
0.847 g/cm3 (70 °C)
Melting point 69.3 °C (156.7 °F; 342.4 K) [2]
Boiling point 361 °C (682 °F; 634 K)
decomposes
232 °C (450 °F; 505 K)
at 15 mmHg[2]
Solubility in water 0.00018 g/100 g (0 °C)
0.00029 g/100 g (20 °C)
0.00034 g/100 g (30 °C)
0.00042 g/100 g (45 °C)
0.00050 g/100 g (60 °C)
Solubility Soluble in alkyl acetates, alcohols, HCOOCH3, phenyls, CS2, CCl4
Solubility in dichloromethane 3.58 g/100 g (25 °C)
8.85 g/100 g (30 °C)
18.3 g/100 g (35 °C)
Solubility in hexane 0.5 g/100 g (20 °C)
4.3 g/100 g (30 °C)
19 g/100 g (40 °C)
79.2 g/100 g (50 °C)
303 g/100 g (60 °C)
Solubility in ethanol 1.09 g/100 mL (10 °C)
2.25 g/100 g (20 °C)
5.42 g/100 g (30 °C)
22.7 g/100 g (40 °C)
105 g/100g (50 °C)
400 g/100g (60 °C)
Solubility in acetone 4.73 g/100 g[5]
Solubility in chloroform 15.54 g/100 g[5]
Vapor pressure 0.01 kPa (158 °C)
0.46 kPa (200 °C)
16.9 kPa (300 °C)
Magnetic susceptibility (χ) -220.8·10−6 cm3/mol
Thermal conductivity 0.173 W/m·K (70 °C)
0.166 W/m·K (100 °C)
Refractive index (nD) 1.4299 (80 °C)
Uses
It is used as an emulsifier in the pharmaceutical and cosmetic industry.
It is used as an auxiliary material in textile.
It is used as an accelerator and softener activator in rubber.
It is used in making candles and crayon.
It is used to harden the soap.
It is used to cover metal powders such as aluminum and iron in fireworks production. Thus, it prolongs the waiting period of the material by preventing oxidation.
It provides hardening by using with glucose in candies.