A, product introduction:
Castor oil is taken from the seeds of castor (oil content is about 50%). The oil content of hulled seeds is as high as 70%, including protein18%. Castor oil is the only commercial oil mainly containing hydroxyl acid. Castor is mainly produced in Brazil, India and the former Soviet Union, and is planted in all provinces in China.
Castor oil contains a lot of ricinoleic acid (more than 80%), so it has many unique properties:
1.Soluble in ethanol, but difficult to dissolve in petroleum ether. The existence of this characteristic can easily distinguish castor oil from other oils.
2. The viscosity is much higher than that of ordinary oils, which is 680CPS at 25℃, the viscosity index is 84, and the friction coefficient is very low (0. 1).
At the same time, castor oil is insoluble in gasoline, with low freezing point and high ignition point. Castor oil has good fluidity, refined castor oil can still flow at -22℃ and has no turbidity after quenching at -50℃. It is an ideal lubricating oil for aviation and high-speed machinery and a protective oil for power belts.
3. It has strong optical activity, because the asymmetric carbon atom in ricinoleic acid, its main fatty acid, is behind 12.
4. The dielectric constant is about 4.30, which is the highest among common oils.
5. The relative density and acetyl value of castor oil are higher than that of common oil.
6. Castor oil hardly undergoes oxidative rancidity in the air and has good storage stability, so it is a typical non-drying liquid oil.
Physical and chemical constants of castor oil:
Relative density (d20℃4℃) 0.9550-0.9700.
Refractive index (N20℃ d)1.4765-1.4819
The viscosity (E020℃) is greater than 14.
Freezing point (℃) 18
Ignition point (℃) 322
Iodine value (g iodine/100g oil) 82-86
Saponification value (mgKOH/g oil) 176- 187
Thiocyanide value 8 1-82
The total fatty acid content (%) is about 96.
The average molecular weight of fatty acids is 290-300.
Fatty acid composition of castor oil (%):
0.5-3.0 of stearic acid
0.6-2.0 of dihydroxystearic acid
3-9 oleic acid
Linoleic acid 2.0-3.5
Ricinic acid 80-88
Castor oil is inedible. High economic value, it is a medicinal laxative; In textile, chemical and light industries, castor oil is used as dyeing aid, lubricant, plasticizing agent, emulsifying agent and raw material for making coatings, paints, soaps and inks.
Castor oil is treated with concentrated sulfuric acid to obtain sulfate with good surface activity (commonly known as Turkish red oil). Castor oil can be dehydrated to obtain dry grease with * * * yoke double bond. A variety of products can be obtained by treating castor oil under different hydrogenation conditions, so castor oil is widely used in various industrial sectors. Castor oil is the closest to the pure compound triglyceride, and only olive oil (containing about 80% oleic acid), safflower oil (more than 70% linoleic acid) and tung oil (containing about 85% eleostearic acid) have this feature in common oils.
The content of unsaponifiable matter in castor oil is less than1%. The vitamin content is low (about 0.05).
Castor seed contains high oil content. Because of the different uses of oil, the oil extraction methods are also different. The medicinal castor oil is cold pressed with a hydraulic press at a temperature not exceeding 50℃, otherwise some impurities will dissolve in the oil and cannot be used as medicine. The oil obtained by cold pressing is called 1 castor oil. After the cake is crushed, it is pressed or leached again to prepare No.3 castor oil (no.2) for industrial use. Castor oil obtained by direct pressing with screw oil press or pre-pressing and leaching can only be used as industrial oil.