What Is Stearic Acid 1840? Specifications, Production, and Uses
- Stearic Acid 1840 is a long-chain saturated fatty acid (mainly C18:0) with a maximum iodine value of 0.5 g I2/100 g and a freezing point of 54–57 °C.[1]
- The product is a white flake or powder solid, with acid value 207–213 mg KOH/g and saponification value 208–214 mg KOH/g.[1]
- Its fatty acid composition is dominated by C16 (55–62%) and C18 (37–43%), making it a blend of palmitic and stearic acids.[1]
- It is obtained from fat splitting and hydrogenation of vegetable oils, including from Refined Bleached Deodorized Palm Stearin (RBDPS).[2]
- It is used for soap, candles, cosmetics, plasticizers, PVC stabilizers, and rubber softeners and vulcanization activators.[3]
Stearic Acid 1840 is one of the most widely used long-chain saturated fatty acids in industry. Its very low iodine value indicates high purity, making it suitable for applications that require stability and good color.
Table of contents
What Is Stearic Acid 1840?
Stearic Acid 1840 is a long-chain saturated fatty acid consisting largely of octadecanoic acid (C18:0) and hexadecanoic acid (C16:0). The number 1840 in the product name refers to the product titer or freezing point of about 54–57 °C, distinguishing it from other grades such as 1800, 1842, and 1860.[1]
The compound has the chemical formula CH3(CH2)16COOH, is solid at room temperature, and is practically insoluble in water but soluble in organic solvents such as alcohol and acetone.[3][4]
In the palm industry, stearic acid is among the long-chain fatty acids sourced from Crude Palm Kernel Oil (CPKO) and refined palm stearin (RBDPS).[2]
Product Specifications
Stearic Acid 1840 specifications are set based on acid value, saponification value, iodine value, freezing point, and fatty acid composition. The very low iodine value is an indicator of product purity and stability.[1]
| Parameter | Limit |
|---|---|
| Form at 30 °C | White powder |
| Acid value (mg KOH/g) | 207–213 |
| Saponification value (mg KOH/g) | 208–214 |
| Iodine value (g I2/100 g) | Max. 0.5 |
| Freezing point / titer (°C) | 54–57 |
| Moisture content (%) | Max. 0.2 |
| Lovibond color (R/Y) | Max. 0.5 / 2 |
| C14 (%) | Max. 3 |
| C16 (%) | 55–62 |
| C18 (%) | 37–43 |
| Other (%) | Max. 1 |
Production and Sources
Stearic acid is obtained by fat splitting of triglycerides at high temperature and pressure, yielding free fatty acids and glycerol, or by hydrogenation of vegetable oils that saturates double bonds using a nickel catalyst.[3]
In Indonesia, the main feedstocks are Crude Palm Kernel Oil (CPKO) and refined palm stearin (RBDPS). A study at the University of North Sumatra shows that RBDPS-based stearic acid 1840 can be produced commercially by distillation, with product iodine value dropping to 0.175 g/100 g.[2]
Product quality is influenced by feedstock iodine value, feed rate, and column base temperature. Reducing feed iodine value to 0.60 g/100 g at a rate of 6.0 t/h and temperature 222 °C yields distillate with 90.78% yield and stable quality.[2]
Uses
Stearic Acid 1840 is used as a raw material for candles, soap, plastics, cosmetics, and rubber softening.[3]
In the rubber industry, stearic acid acts as a vulcanization activator and softener, while in plastics it is used as a PVC stabilizer and metal soap.[2]
High-purity products (triple pressed, iodine value 0.5–1.0) suit cosmetics, food, and pharmaceuticals, while rubber grades with higher iodine values are used in tire and technical rubber industries.[2]
Summary
Stearic Acid 1840 is a long-chain saturated fatty acid with a maximum iodine value of 0.5 g I2/100 g, acid value 207–213 mg KOH/g, and freezing point 54–57 °C. It is obtained from fat splitting and hydrogenation of vegetable oils, mainly from CPKO and RBDPS, and is used for soap, candles, cosmetics, plasticizers, and the rubber industry.
References
- Stearic Acid 1840 (SA 1840) technical specification, CAS 57-11-4. https://www.xfrjester.com/products/stearic-acid-1840.html
- University of North Sumatra. Optimization of Stable Refined Bleached Deodorized Palm Stearin (RBDPS)-Based Stearic Acid to Meet Quality Standards. https://repositori.usu.ac.id/handle/123456789/43758
- PT Sinar Mas Agro Resources and Tbk (SMART). Oleochemicals — long-chain fatty acids. https://www.smart-tbk.com/produk-layanan/oleokimia/
- Siregar (2017). Fatty Acid and Ester Characteristics. https://id.scribd.com/document/112063184/Chapter-II