Sebacic acid, manufacture

During the early forties flexible PVC use was mainly limited to military applications, including wire and cable, and various film and sheeting applications, etc. With the conclusion of World War II, new markets for PVC developed rapidly. Aside from DOP, which was commercialized in 1940(4), dicapryl phthalate (DCP) was introduced by Rohm and Haas C5), also in the early forties. With the development of plastisols(6), DCP became a plasticizer of choice because of the favorable balance of properties it imparted — especially low viscosity. However, DCP s subsequent growth has been limited since capryl alcohol (octanol-2), a monohydric secondary alcohol, is a by-product of limited volume sebacic acid manufacture. 

HOOC-[CHa]8-COOH, CioH.aO. Colourless leaflets m.p. 134°C. Manufactured by heating castor oil with alkalis or by distillation of oleic acid. Forms an anhydride, m.p. 78 C. The esters of sebacic acid are used as plasticizers, especially for vinyl resins. 

The by-product of this process, pelargonic acid [112-05-0] is also an item of commerce. The usual source of sebacic acid [111-20-6] for nylon-6,10 [9008-66-6] is also from a natural product, ticinoleic acid [141-22-0] (12-hydroxyoleic acid), isolated from castor oil [8001-79-4]. The acid reacts with excess sodium or potassium hydroxide at high temperatures (250—275°C) to produce sebacic acid and 2-octanol [123-96-6] (166) by cleavage at the 9,10-unsaturated position. The manufacture of dodecanedioic acid [693-23-2] for nylon-6,12 begins with the catalytic trimerization of butadiene to make cyclododecatriene [4904-61-4] followed by reduction to cyclododecane [294-62-2] (see Butadiene). The cyclododecane is oxidatively cleaved to dodecanedioic acid in a process similar to that used in adipic acid production. 

Alkali Fusion. Tha alkaU fusion of castor oil using sodium or potassium hydroxide in the presence of catalysts to spHt the ricinoleate molecule, results in two different products depending on reaction conditions (37,38). At lower (180—200°C) reaction temperatures using one mole of alkah, methylhexyl ketone and 10-hydroxydecanoic acid are prepared. The 10-hydroxydecanoic acid is formed in good yield when either castor oil or methyl ricinoleate [141-24-2] is fused in the presence of a high boiling unhindered primary or secondary alcohol such as 1- or 2-octanol. An increase to two moles of alkali/mole ricinoleate and a temperature of 250—275°C produces capryl alcohol [123-96-6] CgH gO, and sebacic acid [111-20-6] C QH gO, (39—41). Sebacic acid is used in the manufacture of nylon-6,10. 

Seb cic Acid. Sebacic acid [111-20-6] C QH gO, is an important intermediate in the manufacture of polyamide resins (see Polyamides). It has an estimated demand worldwide of approximately 20,000 t/yr. The alkaline hydrolysis of castor oil (qv), which historically has shown some wide fluctuations in price, is the conventional method of preparation. Because of these price fluctuations, there have been years of considerable interest in an electrochemical route to sebacic acid based on adipic acid [124-04-9] (qv) as the starting material. The electrochemical step involves the Kolbn-type or Brown-Walker reaction where anodic coupling of the monomethyl ester of adipic acid forms dimethyl sebacate [106-79-6]. The three steps in the reaction sequence from adipic acid to sebacic acid are as follows ... 

Plasticizers can be classified according to their chemical nature. The most important classes of plasticizers used in rubber adhesives are phthalates, polymeric plasticizers, and esters. The group phthalate plasticizers constitutes the biggest and most widely used plasticizers. The linear alkyl phthalates impart improved low-temperature performance and have reduced volatility. Most of the polymeric plasticizers are saturated polyesters obtained by reaction of a diol with a dicarboxylic acid. The most common diols are propanediol, 1,3- and 1,4-butanediol, and 1,6-hexanediol. Adipic, phthalic and sebacic acids are common carboxylic acids used in the manufacture of polymeric plasticizers. Some poly-hydroxybutyrates are used in rubber adhesive formulations. Both the molecular weight and the chemical nature determine the performance of the polymeric plasticizers. Increasing the molecular weight reduces the volatility of the plasticizer but reduces the plasticizing efficiency and low-temperature properties. Typical esters used as plasticizers are n-butyl acetate and cellulose acetobutyrate. 

Polyamides, commonly known as nylons, may safely be used to produce articles intended for application in processing, handling, and packaging of food, including for products intended to be cooked directly in their packages. Nylon resins are manufactured by condensation of hexyamethylenediamine and adipic acid (nylon 66) or sebacic acid (nylon 610), by the polymerization process, e.g., of co-laurolactam (nylon 12), or by condensation and polymerization, e.g., nylon 66 salts and s-caprolactam. 

Figure 13. Manufacture of sebacic acid for adipic acid. 

Dibutyl sebacate is manufactured by the esterification of n-butanol and sebacic acid in the presence of a suitable catalyst, and by the distillation of sebacic acid with -butanol in the presence of concentrated acid. 

War I (35). Although the entire castor plant is poisonous, the seeds contain the highest concentration of ricin (36). For hundreds of years, countries all over the world have cultivated the plant for its oil, specifically for use as a laxative and for lubrication. Castor oil has many industrial and commercial uses, having served as a lubricant for racing engines (Castrol-R racing motor oil) and as an additive in paints and varnishes. One of its derivatives, sebacic acid, is a component in the production of nylon and aUcyd resins, and contributes to the manufacture of plasticizers, lubricants, diffusion pump oils, cosmetics, and candles (35). India is currently the world leader in production, followed by China and Brazil (35). 

Another opportunity for the automotive chemist to improve the environmental imperative is to utilize bio-based materials as building blocks. An outstanding example is the manufacture of nylon 6-10 from castor oil. The BASF Corporation has plans to utilize the product as an alternative to nylon 6. The castor oil is treated with caustic soda and heat to render the sebacic acid portion of the polymer (Equation 12.2). 

Now it is possible to produce cis-decalin or trans-decalin, with over 80% selectivity at 100% conversion by using some zeolite-supported catalysts at 200°C. cis-Decalin may have potential industrial application as the starting material for making sebacic acid. Sebacic acid can be used for manufacturing Nylon 6,10 and softeners [Weissermel and Arpe, 1993],... 

Pyrolytic decomposition in the presence of alkali at 250-275 °C yields sebacic acid, 2-oct ol and hydrogen. Sebacic acid (decanedioic acid) is condensed with hexamethylenediamine in the manufacture of 6-10 Nylon. 

Plasticizers, which are added to improve the flexibility, softness and processibility of plastics, constitute a broad range of chemically and thermally stable products of a variety of chemical classes. Their principal use is in thermoplastic resins, and 80-85% of the world s production of plasticizers are used in polyvinyl chloride (PVC) manufacturing. Approximately 450 plasticizers are commercially available. Many are esters of carboxylic acids (e.g. phthalic, isophthalic, adipic, benzoic, abietic, trimellitic, oleic, sebacic acids) or phosphoric acid. Other plasticizers are chlorinated paraffins, epoxidized vegetable oils and adipate polymers. 

Sebacic acid is an important intermediate in the manufacture of polyamide resins. It is obtained on a large scale by saponification of castor oil. It is now obtained by electrochemical process involving the following three steps (Scheme 135). 

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