Product Catalog

Castor oil is derived from the seed of Ricinus communis L. which grows in tropical or subtropical regions such as Central Asia, Tanzania, Brazil, and Southern Kazakhstan to name a few. It occurs as a perennial or annual plant and is considered a drought resistant crop in India. Unfortunately in 1972, economic pressures created circumstances which led to the United States losing its domestic supply of castor oil and the US became dependent on foreign countries for both the seed and the oil. As of 1991, any castor seed produced in the US has to be shipped to Mexico for expression of the oil from the seed. As a result, the US is many years behind in the expression technology. However, the expression of the oil from this seed is done in a similar manner to most other oil seeds. The seeds are collected when ripe: as the capsules dry, they open and discharge the seeds. The seeds are then cleaned, decorticated, cooked and dried prior to extraction. Cooking is done in order to coagulate protein, which is necessary to permit efficient extraction, and to free the oil for efficient pressing. It is done at 80°C, under airtight conditions. After cooking, the material is dried at 100°C, to reach a moisture content of approximately 4 percent.

First stage of extraction is pre - pressing using a high pressure continuous screw press - expeller. The expeller usually consists of a barrel containing a stainless steel helical screw. The pitch of the screw flights gradually decreases towards the discharge end, to increase the pressure on the pulp as it is carried through the barrel. Extracted oil is filtered, and collected in a settling tank. Material removed from the oil, called foot, is fed back into the stream of fresh material. Material discharged from the press, called cake, contains 8 to 10 percent oil. It is crushed into coarse meal, and subjected to solvent extraction with hexane or heptane. Continuous processing is used, based on the principle of counter current flow of solvent and oil bearing material. The oil is removed effectively, as the material comes into contact with increasingly purer solvent. After extraction, solvent is removed by distillation, and ther resulting oil is processed in similar manner as oil from the pressing step.

Once the oil has been expressed from the seed, it is necessary to remove any impurities from the oil that makes it such an important commodity. The oil is essentially a pure triglyceride, and contains almost 90% of glyceryl tricinoleate. It is the ricinoleic triglyceride that is needed in order to produce high quality castor oil that will be used for the chemical reactions. Characterizing properties of castor oil include a higher density, viscosity, and reactivity than common triglycerides found in other vegetable oils. These properties are exploited when refining the oil from the impurities. The steps to refining the crude oil include settling and degumming of the oil, bleaching, neutralization, and deodorization of the oil. The settling and degumming of the crude oil is done to remove the aqueous phase from the lipid and to remove phospholipids from the oil. Bleaching of the oil results in the removal of coloring materials and the removal of phospholipids and oxidation products due to the adsorption of the impurities to neutral clay. Care must be taken because a highly acid activated clay can react with the oil and cause an undesirable dehydration reaction. Neutralization can be done in one of two ways: by alkali (chemical) or steam stripping (physical) means. The neutralization step is necessary to remove free fatty acids from the oil. Caustic soda (alkali) is mixed in the proper amounts and the aqueous solution (called soapstock) is removed, leaving the neutral oil behind. Unfortunately, the use of alkali to neutralize the oil results in poor soapstock separation and high neutral oil losses. This is why steam stripping is preferable. Steam stripping is done under vacuum to remove moisture, free fatty acids, odor bodies, and other impurities from the oil. Because it is performed under vacuum conditions, the oil can be kept at a low temperature, preserving its chemical structure and not subjecting it to temperature in which undesirable dehydration reactions can occur.

Commodities Used, Methods for Each, and Yield of Oil
As mentioned earlier in this paper, the oil is extracted from the seed of the Ricinus communis L. plant. Castor seeds contain 50-55% oil, and chemical modification of that oil has resulted in new products that continue to emerge as time goes on. The oil itself is composed of a unique aliphatic acid that is not found in the oils of any other plant. Though this crop disappeared from the US in 1972 due to economic pressures, steps have been taken to restore this crop domestically to reduce American dependency of other countries to produce it.

Castor meal - organic manure
Hybrid Castor Seeds

Castor Oil esters
Viscosity reducing additive

Surfactants
Pigment Wetting Agents

The chemical structure of castor oil is of great interest because of the wide range of reactions it affords to the oleochemical industry and the unique chemicals that can be derived from it. These derivatives are on par with petrochemical products for use in several industrial applications. In fact, they are considerably superior since they are from renewable sources, bio-degradable and eco-friendly. Castor Oil is regarded as one of the most valuable laxatives in medicine. Castor Oil forms a clean, lightcolored soap, which dries and hardens well and is free from smell. Externally, the oil has been recommended for various cutaneous complaints. Castor Oil is an excellent solvent of pure alkaloids and such solutions of Atropine, Cocaine, etc., as are used in ophthalmic surgery. It is also dropped into the eye to remove the after-irritation caused by the removal of foreign bodies. Castor Oil is finding increasing uses in the industrial world. It figures largely in the manufacture of the artificial leather used in upholstery; it furnishes a coloring for butter, and from it is produced the so-called 'Turkey-red' oil used in the dyeing of cotton textures. It is an essential component in some artificial rubbers, in various descriptions of celluloid, and in the making of certain waterproof preparations, and one of the largest uses is in the manufacture of transparent soaps. It also furnishes sebacic acid which is employed in the manufacture of candles, and caprylic acid, which enters into the composition of varnishes.