Alkali‐catalyzed alcoholysis of crambe oil and camelina oil for the preparation of long‐chain esters

Abstract

The alcoholysis of crambe and camelina oils was carried out with oleyl alcohol, alcohols derived from crambe and camelina oils, and n-octanol using potassium hydroxide as catalyst to prepare alkyl esters. Conversions to alkyl esters were about 70% with oleyl alcohol, 20-45% with crambe and camelina alcohols, and 60% with n-octanol. The conversion to esters for crambe and camelina oil with oleyl alcohol and n-octanol increased with increasing molar excess of alcohol. Composition of the alkyl esters formed was as expected from the composition of the reaction partners.Crambe (Crambe abyssinica) and camelina (Camelina sativa) are less investigated oil plants, whose cultivation on poor nutrient soils is expected to be successful. These oil plants are regarded as industrial resources for different oleochemical applications because crambe oil is a rich source (1,2) of erucic acid (cis-13-docosenoic acid; ca. 56%), and camelina oil is a source (3) of α-linolenic acid (all-cis-9,12,15-octadecatrienoic acid; ca. 38%).The objective of the present work was to prepare alkyl esters of crambe and camelina oils that may have useful applications in lubricants and cosmetics. Transesterification (alcoholysis) of triacylglycerols with alcohols catalyzed by alkali (4-7) or acid catalysts (8,9) is well known and often used for the preparation of alkyl esters. We report here the potassium hydroxide-catalyzed alcoholysis of crambe and camelina oils with long-chain alcohols, such as oleyl alcohol and alcohols derived from crambe and camelina oils, for the preparation of mixtures of long-chain and very long chain wax esters resembling those of jojoba oil. Although the main chain lengths of the expected wax esters are C40 and C44, these esters may be useful as surrogates for jojoba (Simmondsia chinensis) wax esters, which have a main chain length of 42 carbon atoms (ca. 50% of the wax esters) (10,11). Jojoba wax is used in cosmetics, pharmaceuticals, and in the food industry because of its practically unchanged viscosity over a wide range of temperatures (12). Owing to the high price of the final product (inability to economically cultivate the plants) it is desirable to find a low-cost jojoba oil substitute (13). We also report the alkalicatalyzed alcoholysis of crambe and camelina oils with n-octanol and isopropanol. The goal was to obtain products similar to enzymatically prepared medium-chain and short-chain esters (14) with properties suitable for applications in cosmetics. EXPERIMENTAL PROCEDURESMaterials. Crambe and camelina were grown in experimental fields. The seeds and refined oils were supplied by the Institut für Pflanzenbau der Landesforschungsanstalt für Landwirtschaft und Fischerei Mecklenburg-Vorpommern (Gülzow, Germany). Fatty acid composition of the oils (designated by number of carbon atoms:number of cis-double bonds) was as follows. Crambe oil: 16:0 = 2%, 18:0 = 1%, 18:1 = 17%, 18:2 = 9%, 18:3 = 6%, 20:0 = 1%, 20:1 = 4%, 22:0 = 2%, 22:1 = 56%, 24:1 = 1%; camelina oil: 16:0 = 5%, 18:0 = 3%, 18:1 = 14%, 18:2 = 16%, 18:3 ...

High-Yield Preparation of Wax Esters via Lipase-Catalyzed Esterification Using Fatty Acids and Alcohols from Crambe and Camelina Oils

“…Of the two lipases tested as biocatalyst for esterification, Novozym 435 was distinctly more active than papaya lipase, yet the latter should be interesting for commercial application because it is an inexpensive plant enzyme preparation occurring in crude papaya latex containing papain that has been used in the food and beverage industries for a long time. Of the two processes for the lipase-catalyzed preparation of esters, that is, alcoholysis as reported recently (17) and esterification as reported in the present work, the products of lipase-catalyzed esterification under vacuum contain waxes in >95% purity due to high conversion into wax esters starting from stoichiometric mixtures of substrates. The lipase-catalyzed alcoholysis of triacylglycerols with alcohols, however, is a direct one-step process, although the products of alcoholysis contain distinctly fewer wax esters compared to those obtained by esterification.…”

“…We have shown recently that alcoholysis of triacylglycerols from seed oils of crambe (Crambe abyssinica) and camelina (Camelina sativa) with long-chain and very long-chain alcohols, catalyzed by Novozym 435 (immobilized lipase B from Candida antarctica), Lipozyme IM (immobilized lipase from Rhizomucor miehei), and papaya (Carica papaya) latex lipase, yields wax esters in moderate to high yields (17). Here, we report the lipase-catalyzed synthesis of wax esters by esterification of long-chain and very long-chain fatty acids with the corresponding alcohols, both derived from seed oils of crambe and camelina.…”

The Ideal Vegetable Oil-based Biodiesel Composition: A Review of Social, Economical and Technical Implications

“…They compared two methods of transesterification developed by Freedman et al 87 and by Maurer. 88 Steinke et al 89 developed both alkali and lipase-catalyzed alcoholeysis of C. satiVa oil. Fro ¨hlich and Rice 86 tested biodiesel from this species in two light transport vehicles.…”

Optimization of Palm-Based Wax Esters Production Using Statistical Experimental Designs

“…Wax esters can be synthesized using chemical and enzymatic methods. The use of homogenous chemical catalyst may lead to several problems such as corrosion of equipment, hazards of handling of the corrosive acids or bases, and high energy consumption as the reaction occurred at elevated temperature (6)(7)(8). On the other hand, enzymatic synthesis offers mild reaction conditions and environmental-friendly process, which have attracted attention since last decade (9)(10)(11).…”