Basics Castor oil By:
Basics Castor oil By: Michael Thielen Castor oil is the raw material of choice for the production of biobased sebacic acid. A number of biobased plastics, for example several partly or fully biobased polyamides are manufactured using sebacic acid as a monomer or as a chemical building block. Another monomer based on castor oil is 11-aminoundecanoic acid. About the castor plant The Castor plant (Ricinus communis) is from the family Euphorbiaceae and grows wild in varied climatic conditions. It produces seeds that contain up to 50 % wt castor oil. The oil can easily be extracted from castor seeds and find its use in a multitude of sectors such as a building block for bioplastics (mainly biobased polyamides), medicine, chemicals industry and in other technologies [4]. India is the largest producer of Castor oil in the world. The expected harvest for 2018 is 1.4 to 1.5 million tonnes of castor seeds,” as K.S. Najappa, CEO of Planters International (Indiranagar Bengaluru, Karnataka, India) told bioplastics MAGAZINE, “which will yield to approximately 700,000 tonnes of Castor oil” [5]. Approximately 86% of the castor seed production in India is concentrated in Gujarat, followed by Andhra Pradesh and Rajasthan. Specifically, the regions of Mehsana, Banaskantha, and Saurashtra/Kutch in Gujarat and the districts of Nalgonda and Mahboobnagar of Andhra Pradesh are the major areas of castor oil production in India. The economic success of castor crops in Gujarat in the 1980s and thereafter can be attributed to a combination of a good breeding program, a good extension model, coupled with access to well-developed national and international markets [12]. Other countries that produce castor oil include Brazil and China. China, however, “does not produce enough castor oil for their own needs,” says Najappa, “so that they import from India.” With view to bioplastics, the main derivative product of castor oil is sebacic acid. The main countries to produce sebacic acid are again India and China. Najappa: “Unfortunately India cannot seriously compete with China, because the Chinese Government gives their manufacturers a lot of incentives” [5]. The world castor seed production has increased from 1.055 million tons in 2003 to 1.440 million tons in 2013 with India being the leading producer and accounts for over 75 % of the total production followed by China and Brazil each accounting for 12.5 and 5.5 % respectively [13] Throughout the growth season, the castor plant responds well to temperatures between 20 – 26°C with a low humidity and grows best in loamy soils with medium texture. Nonetheless, castor plants are renowned as a low maintenance crop with the ability to be cultivated especially on marginal lands and can tolerate various weather conditions. Biochemicals from castor oil do not affect food production or cause any land use change. Castor oil is toxic and thus not part of food chain, a characteristic that is drawing more and more attention lately. The castor plants grow on arid to marginal lands with little or no agrochemicals needed [7]. From castor oil to bioplastic Castor oil is a vegetable oil extracted from the castor bean (or better from the castor seed as the castor plant, Ricinus communis, is not a member of the bean family Fabaceae; it is a member of the Euphorbiaceae). Castor oil ranges from colorless to very pale yellow liquid with mild or no odor or taste. Its boiling point is 313°C and its density is 0.961 kg/cm3 [1]. After the oil extraction, the Castor meal (also known as Castor cake) is separated and the oil is subsequently hydrolyzed to a mixture of glycerine and ricinoleic acid in the refining process. Ricinoleic acid, a monounsaturated, 18-carbon fatty acid, is unusual compared to other fatty acids due to its hydroxyl functional group on the 12th carbon. This functional group renders ricinoleic acid unusually polar, and also increases its chemical reactivity, a property that is unique when compared with most of the others vegetable oils. It is the hydroxyl group which makes castor oil and ricinoleic acid susceptible of an easy chemical derivatization, thus a valuable chemical feedstocks [2]. In a next step the ricinoleic acid is converted into either undecenoic acid (monomer for PA11) or sebacic acid (one of the monomers for PA6.10 and PA10.10). This sebacic acid (or decanedioic acid (the IUPAC name), or 1,8-octanedicarboxylic acid or C10H18O4 or [HOOC(CH2)8COOH]) is a dicarboxylic acid that can for example be used as monomer for different types of polyamides [3]. In the commercially available polyamides PA 4.10, 5.10 and PA 6.10, the ‘10’-component is based on this dicarboxylic acid with 10 carbon atoms. Since the other component (the diamine) in these resins usually is not made from renewable resources, these partly biobased polyamides have 63% (PA 6.10) biobased content. Polyamides 4.10, 5.10, PA 10.10 and PA 10.12 can be 100% biobased as here the diamine can be derived from renewable resources as well. In the case of PA 10.10 both monomers (1,10-decamethylene diamine and sebacic acid) are derived from castor oil [8]. A third example is PA 11. Here a single monomer is being used. First the ricinoleic acid from the castor oil is converted into undecanoic acid [H2C=CH-(CH2)-COOH] via a catalytic reaction (methanolysis). This is then further converted into 11-aminoundecanoic acid in a subsequent catalytically supported reaction with ammonia [9]. This 100% biobased polyamide has been discovered and marketed since as far back as 1947 [3]. Sebacic acid is also found as ingredient in the cosmetic industry, as thickeners for coatings and lubricants, as antifreeze for lubricants, as plastizers, stabilizers, anticorrosion chemicals or other polymers such as polyols and polyesters and many other uses. 52 bioplastics MAGAZINE [03/18] Vol. 13
Basics References [1] Aldrich Handbook of Fine Chemicals and Laboratory Equipment, Sigma- Aldrich, 2003 (found in Wikipedia) [2] Wikipedia: http://en.wikipedia.org/wiki/Castor_oil [3] Basics of Bio-polyamides, bioplastics MAGAZINE, vol 5, issue 03/2010 [4] Ogunniyi DS (2006) Castor oil: a vital industrial raw material. Bioresour Technol 97:1086–1089 [5] Najappa K.S: personal information May 2018, Planters International (Indiranagar Bengaluru, Karnataka, India) [6] FAOSTAT, 2006-2009, FAO data based on imputation methodology [7] Wang, M.S., Huang, J.C., 1994, Nylon 1010 properties and applications, J. Pol. Eng., 13 (2), pp155-174 & New Crop Resource Online Program, Purdue University, www.hort.purdue.edu/newcrop/default.html [8] VESTAMID® Terra - Because we care (brochure of Evonik, Marl Germany), 2012 [9] Endres, H.-J., Siebert-Raths, Engineering Biopolymers, Carl Hanser Verlag, 2011 [10] www.usitc.gov/publications/701_731/pub3775.pdf [11] Thielen, M. Castor oil, an important source for bioplastics, bioplastics MAGAZINE 03/2012 (with the help of Evonik and nova-Institute) [12] Patel, V.R. et. al.: Castor Oil: Properties, Uses, and Optimization of Processing Parameters in Commercial Production, Lipid Insights. 2016; 9: 1–12. [13] Severino L.S. et.al.: Review on the challenges for increased production of castor. Agron J 104:853–880, (2012) Castor bean OVENS & FURNACES Large-Capacity Walk-In Ovens Standard sizes to 786 cu. ft. Special sizes to your specs Gas & Electric models Choice of air flow patterns Temps to 1200ºF www.grievecorp.com 847-546-8225 GRIEVE CORPORATION AD4393g Color Castor oil is the most versatile vegetable oil in the world. lt is biodegradable and is a renewable resource. lts applications reach across numerous industries. The bioplastics industry has been experiencing an increase in the use of Castor oil for the last few years. Castor plant The annual conference of the International Castor oil Association brings together major participants in the industry to exchange views and discuss latest news and trends about castor oil. The next conference will be held June 6-8, 2018 in Stockholm, Sweden. Visit the ICOA website for conference details. www.icoa.org bioplastics MAGAZINE [03/18] Vol. 13 53
