文章目录[隐藏]
Product Introduction
Stearic acid, with the chemical formula C(18)H(36)O(2) and a molecular weight of 284.48, is a compound known as octadecanoic acid. It is produced by hydrolyzing fats and is primarily used to produce stearic acid salts. It is widely used in cosmetics, plasticizers for cold-resistant plastics, release agents, stabilizers, surfactants, rubber vulcanization accelerators, waterproofing agents, polishing agents, metal soaps, flotation agents for metallic minerals, softeners, pharmaceuticals, and other organic chemicals.
Stearic Acid Production Process
Stearic acid is a fatty acid widely found in nature. It is present in varying amounts in almost all fats, with higher content in animal fats (up to 24% in tallow), lower in plant oils (0.8% in camellia oil, 6% in palm oil), and up to 34% in cocoa butter. Industrial production of stearic acid mainly uses two methods: distillation and pressing.
- Distillation Method: Add 6 tons of cottonseed oil to a hydrolysis vessel, along with 120kg of stearic acid phenol sulfonic acid and stearic acid naphthalene sulfonic acid. Pass steam until the oil layer becomes transparent, then add 4200kg of water. Continue heating to boiling, react at atmospheric pressure for 7.5 hours, clarify for 0.5 hours, and separate the glycerin water. Add 120kg of hydrolysis agent, heat with steam until the oil layer is transparent, then add 3600kg of water, and react for about 10 hours. The endpoint of hydrolysis is when the acid value reaches 190mg KOH/g or higher. After clarification, separate the glycerin water, and wash with 7kg of salt and 3600kg of water. Perform a secondary wash with 14kg of salt and 4200kg of water. After the first wash, clarify for 0.5 hours; after the second wash, clarify for 2 hours. Separate the lower acid water, and reserve the upper mixed fatty acids.
2000kg of mixed fatty acids are added to a distillation still for reduced pressure distillation, with still temperature at 250-255°C, tower temperature at 210-220°C, top temperature at 200-210°C, and tower top pressure at 0.53-0.93kPa. After balance of feed, discharge, and residue, switch to continuous operation with 100% feed, 40% discharge, and 60% residue. The residue is used to produce tertiary stearic acid. The discharge, after analysis showing an iodine value below 2mg/100g, is mixed with 1000kg of stearic acid and 3kg of 92.5% sulfuric acid in an acid washing tank, boiled and washed. After removing acid foot, heat 450kg of stearic acid in a decolorizing tank to 190°C, then add 150mL of pure soda and 11kg of dry clay. Decolorize under reduced pressure and stirring at around 105°C for about 45 minutes. Filter, and mold to obtain primary stearic acid.
Glycerin water separated during hydrolysis is neutralized with lime milk at 80-100°C, and refined glycerin is obtained through processes including suction filtration, concentration, pressure filtration, vacuum distillation, and activated carbon decolorization.
- Pressing Method: Using animal or vegetable oils as raw materials, produce primary stearic acid through high-pressure hydrolysis, washing, reduced pressure distillation, pressing, bleaching, and crystallization processes in the presence of a hydrolysis agent (e.g., zinc oxide).
- Hydrolysis Method with Sulfonation Agents: Hydrolyze hardened oils, tallow, or mutton fat in the presence of sulfonation agents (e.g., benzene or naphthalene sulfonic mixtures), followed by acidification, distillation, pressing, and acid washing to obtain the finished product.
- Hydrogenation of Oleic Acid Method.
- Synthetic Fatty Acid Method: Use synthetic fatty acids C(10) to C(20) and C(18) to C(20) fractions as raw materials, and produce stearic acid through melting, acid washing (with 1% sulfuric acid), molding, pressing, melting, acid washing, and dehydration crystallization.
Stearic Acid Effects and Uses
Softener, stabilizer, lubricant, etc.
Stearic Acid Applications
Primarily used in the production of stearic acid salts: sodium stearate, magnesium stearate, calcium stearate, lead stearate, aluminum stearate, cadmium stearate, iron stearate, potassium stearate.
In the cosmetic industry, it is an essential raw material for making general emulsified products such as cold creams, foundation creams, shaving creams, hair lotions, and skincare lotions. In the rubber industry, it acts as a vulcanization activator for natural and synthetic rubber and latex, and as a softener. In the plastic industry, it is used as a plasticizer, stabilizer, and lubricant. In the textile industry, it is used as a yarn lubricant and in the production of silk finish agents. It is also used in making release agents, polishing pastes, defoamers, metal flotation agents, paint flatteners, wax paper polishing agents, and waterproofing agents for textiles. It serves as a solvent for oil-soluble pigments and a raw material for stearic acid esters and salts such as stearic acid methyl ester, stearic acid calcium, and stearic acid potassium. It is non-toxic and packaged in woven bags with plastic liners or cardboard boxes, with each bag (or box) weighing 25kg or 50kg. Storage and transportation should follow general chemical regulations, kept in a cool, dry place.
Industrial Product
Industrial stearic acid appears as white or slightly yellow granules or blocks, a mixture of 45% stearic acid and 55% oleic acid, with a slight fatty odor. It is classified into primary (formerly known as triple-pressed, processed by three presses), secondary (formerly known as double-pressed, processed by two presses), and tertiary (formerly known as single-pressed or unpressed). Primary and secondary stearic acids are white waxy solids with a shiny appearance or crystalline grains. Tertiary stearic acid is a pale yellow waxy solid.
Standards: GB9103-88
Industrial stearic acid is widely used in cosmetics, plasticizers for cold-resistant plastics, release agents, stabilizers, surfactants, rubber vulcanization accelerators, waterproofing agents, polishing agents, metal soaps, flotation agents for metallic minerals, softeners, pharmaceuticals, and other organic chemicals.
It is also used as a solvent for oil-soluble pigments, crayon slip agents, wax paper polishing agents, and emulsifiers for stearic acid glyceryl esters.
In the food industry, it is used as a lubricant, defoamer, and raw material for food additives such as stearic acid glyceryl esters, stearic acid sorbitan esters, and sucrose esters. It serves as a raw material for additives and daily chemical products.
Stearic acid is extensively used in the manufacturing of PVC plastic pipes, sheets, profiles, and films. It acts as a heat stabilizer for PVC, providing excellent lubrication and thermal stability. In PVC pipe production, stearic acid helps prevent charring during processing, and in PVC film processing, it is an effective heat stabilizer and can counteract color changes caused by exposure to sulfur compounds.
Rubber Industry
Stearic acid plays a critical role in the synthesis and processing of rubber. It is a widely used vulcanization activator for natural and synthetic rubber and latex, and also acts as a plasticizer and softener. During synthetic rubber production, stearic acid is used as an emulsifier, in foam rubber production it serves as a foaming agent, and it is also used as a release agent for rubber products.
Cosmetics Industry
Stearic acid is used in cold creams and vanishing creams as an emulsifying agent, helping to create a stable, smooth, white cream. Stearic acid is also a primary ingredient in the production of almond lotion and milk lotion. Stearic acid esters are even more widely used in the cosmetics industry.
Packaging and Storage of Stearic Acid
[Storage Conditions] Store in a cool, dry, and well-ventilated area. Keep away from fire sources and oxidizers. Follow standard chemical storage and transport guidelines.
[Packaging] Bulk: 25 kg in cardboard drums. Samples: 1 kg in aluminum foil bags. Custom packaging is also available upon request.
[Shipping] Delivered by courier or logistics. Domestic courier arrives within 3 days; logistics within 5 days. Shipping costs are typically included in domestic quotes.
[Shelf Life] Two years
