Polyamides from plant oils

Presently, the sebacic acid synthesis is carried out industrially only in the USSR (capacity about 2000 tonnes/year). Fairly large amounts are produced from castor oil, a naturally renewable raw material. The capital costs for large plants are indeed considerable. Sebacic acid is used, for example, as a component in polyamides. Seba-cates are used as special plasticizers and synthetic lubricants. 

Generally speaking, numerous synthons can be extracted from biomass. One known example is that of ethylene, produced from the dehydration of ethanol which is a very common product of fermentation. Another example is 1,3-propanediol, which is a monomer used as a building block for the production of polymers such as polyesters and polyurethanes. Several industrial processes have studied its production by fermentation with the aim of producing it directly from inexpensive plant raw materials (starch or sucrose). To synthesize polyamides and polyesters, we also aim to produce a,(o-dicarboxylic acids by the biological conversion of esters from vegetable oils. 

ADMET has been used to take advantage of several natural polymer feedstocks, mainly plant oils and fatty acids (Figure 13.26) [190]. An initial study optimized the ADMET polymerization of a variety of plant oils, and yields of40—60% were obtained [191]. A set of polyamides were synthesized by ADMET polymerization of monomers ultimately derived from ricinoleic acid, the main fatty acid of castor oil [192]. Similarly, ADMET was utilized to polymerize 1,3-di-lO-undecenoxy-2-propanol, a castor oil-based diene, which was subsequently reacted with... 

The Diels-Alder reaction is also involved in the synthesis of dimer acid from oleic acid or plant oils. Dimer acids typically consist of a broad distribution of highly branched 36-carbon dicarboxylic acids that contain cyclohexene groups. They are formed using clay catalysts at a temperature above 200°C, and are manufactured worldwide for employment in polyamide resins (Breuer, 2007 Heidbreder et al, 1999). The hydrogenation of dimer acids yields dimer diols, which are useful as polyols in the preparation of polyurethanes (Heidbreder et al., 1999). 

Caraway (Camm carvii). This is one of a group of plants whose seed oils contain petroselinic acid (6-18 1). This acid reaches levels of 35 3% in caraway, 66-73% in carrot, 31-75% in coriander, and 80% in parsley. This isomer of oleic acid has some potential use as a source of lauric and adipic acids, produced by oxidative cleavage. The latter, an important component of many polyamides (nylons), is usually made from cyclohexane by a reaction that is reported to be environmentally unfriendly (90). 

AlkL-membrane protein. The latter contributes to the transport of the ester into the cell through the hydrophobic membrane. The hydroxylation proceeds very efficiently leading to the hydroxylated product 52 as well as the aldehyde product 53 through further oxidation. When integrating a recombinant transaminase into the whole-cell catalyst, conversion of the aldehyde 53 then leads to the formation of the target product 54. As an amine donor, L-alanine was used. It is noteworthy that this process technology has been applied on pilot plant scale by Evonik Industries AG in connection with the production of co-amino-lauric acid for polyamide-12 from palm kernel oil [133]. 

---