What is Stearic Acid
Stearic acid is a saturated fatty acid with higher hydrocarbons and it’s usually called as Octadeconic acid. Stearic acid is one of the most common saturated fatty acids found in nature and occurs in many animal and vegetable fat oils. It is a waxy white solid with chemical formula of CH3(CH2)16CO2H and molar mass of 284.48 g/mol. Stearic acid can be obtained from the hydrogenation of unsaturated vegetable oils. Stearic acid is actually a mix of stearic acid, palmitic acid and oleic acid. Stearic acid is available in different grades in the market, such as rubber grade, candle grade, double pressed grade and triple pressed grade. The many grades differ on the basis of iodine number, saponification value, acid number and the fatty acid composition.
Stearic acid is commercially produced from fatty acids by saponification with water at a high temperature and pressure, leading to the hydrolysis of triglycerides. The resulting product then distilled to remove the water. Stearic acid produced usually consist some palmitic acid as well, further purification can be done to get a high purity product.
There are different manufacturing process depending on the grade of stearic acid required and the type of raw material. Tallow and Grease are the most common raw material used for the production of stearic acid. There are two main steps for the production of stearic acids.
Firstly raw materials (fat or oil) are hydrolyzed to produce a mixture of fatty acids and glycerin followed by separation of two products.
Purification and separation of fatty acid mixtures.
The Uses of Stearic Acid
Detergent and Soap IndustryStearic acid is primarily applied in the production of detergents, soaps, and cosmetics such as shampoos and shaving cream products. Soaps are manufactured from the saponification of stearic acid triglycerides. Esters of stearic acid are used to produce shampoos, soaps, and other cosmetic products. Citric acid can harden soaps and give shampoos a pearly color and consistency.
Paint IndustryStearic acid is a very effective wax modifier used in candle making. It is a non-toxic additive that increases the opacity and hardness of candles. It also increase candle whiteness and aid in holding the candles shape of freestanding candles in the warmer months. It increases the candle durability consistency and melting point. Due to its stability and shaping property it is used in making various art and craft products.
Candles ProductionStearic acid candle grade is utilized in the production of candles because of its excellent properties such as hardening the wax and strength of the candle. Stearic acid exhibits properties of activator and thickener in the wax manufacturing process. It also has an impact on the melting point of the wax, improving the durability and consistency of the candle.
Rubber IndustryStearic Acid rubber grade is used in vulcanization of surfactants, making plasticizers, softeners, water proofing agents, PVC additives etc. It is used in making tires. It acts as stock lubricant enabling easy mold flow and release during extrusion.
Other ApplicationsIn the ceramic industry, Stearic acid is a common lubricant in the injection molding and pressing of ceramic powders. It is used in the manufacture of lead acid batteries as a negative plate additive.
|SYNONYMS||n-octadecanoate; 1-heptadecanecarboxylic acid; n-octadecylic acid; cetylacetic acid; Acide octadecylique; Acide stearique; stearophanic acid|
|PHYSICAL STATE||White to yellowish solid|
|MELTING POINT||67 – 69 C|
|SOLUBILITY IN WATER||0.1-1 g/100 ml at 23 C|
|NFPA RATINGS||Health: 1 Flammability: 1 Reactivity: 0|
|FLASH POINT||196 C|
|STABILITY||Stable under ordinary conditions|
|IODINE VALUE||0.5 max|
|ACID VALUE||208 – 210|
|SAP VALUE||209 – 211|
|TITER||TITER : 54 – 56 C|
|COLOR||0.5 R / 2.5 Y|
|CARBON DISTRIBUTION||C14 (1% max) + C16 (62% max) + C18 (45% max)|