Oleate FAMEs

C12 to C20, primarily Ci6 to ( is), used as surface lubricants in the manufacture of food-contact articles. The method, which uses ethyl palmitate (Eastman Chemicals No. 1575 Red Label) as an internal standard, has been validated at 200 ppm total FAME [185]. Other FAME standards (methyl palmitate, methyl stearate, methyl oleate, methyl linoleate and methyl linolenate) are available (Applied Science Laboratories) [116], Worked out examples of additive determinations are given in the Food Additives Analytical Manual [116], which also describes a great many of indirect food additives, such as BHA, BHT, TBHQ, l-chloro-2-propanol, DLTDP, fatty acid methyl esters, w-heptyl-p-hydroxybenzoate, propyl-gallate, sodium benzoate, sodium stearoyl-2-lactylate, sorbitol and phenolic antioxidants. EPA methods 606 and 8060 describe the CGC separation of phthalate esters (direct injection) (cf. Figure 4.2). 

The ability of titanium-grafted silicas in catalyzing the epoxidation with TBHP of fatty compounds was first tested on two pure Qg monounsaturated FAMEs methyl oleate (ds-9-octadecenoate Scheme 12.1) and methyl elaidate (trans-9-octadecenoate) [49]. In both cases, selectivity to 9,10-epoxystearate was very high (>95%) and the reaction was fully stereospecific, confirming that epoxidation with titanium catalysts and TBHP proceeds via a non-radical mechanism with retention of configuration at the C=C bond. Ti-MCM-41 was more active than Ti-SiC>2 (Fig. 12.1). Actually, methyl oleate was almost completely converted after... 

Fig. 12.1 Conversion of fatty acid methyl esters (FAMEs) methyl oleate ( ) and methyl elaidate ( ) vs. reaction time over Ti-MCM-41 (a) and overTi-Si02 (b). (Adapted from [49]).

Figure 5 compares the conversion yields of each FAME, transesterified from rapeseed oil, after a 10-min reaction with a 1.0%(w/w) catalyst at a molar ratio of 1 6 and 60°C. In all the catalysts studied, oleic acid was best converted to methyl oleate. 

Two previous studies (Moser et al., 2007, 2006) explored the effects of synthetic compounds with hydrocarbon tail-group structures resembling those of FAME with attached bulky moieties on the CP and PP of SME. These studies examined novel fatty ethers made from the reaction of various alcohols (C2—Cm) with epoxidized alkyl oleates in the presence of sulfuric acid catalyst. Bulky esters (isopropyl and isobutyl) were chosen to further enhance the low temperature fluidity of the synthetic adducts produced. As the chain length of the ether moiety attached to the fatty backbone increased in length, a corresponding improvement in low temperature performance was noticed. Although the materials had improved low temperature properties over that of neat SME, none of the synthesized compounds demonstrated effectiveness in decreasing CP or PP when added to SME. 

The FAMES (fatty acid methyl esters, ie, biodiesel constituents) methyl oleate, methyl palmitate, methyl stearate, methyl hnoleate, and methyl hnolenate. 

Hie analysis of each of the most abundant FAMEs by DSC at 5 C/min has permitted us to identify the peaks obtained on the cooling and heating scans of rapeseed and palm biodiesels. Table 13.2 lists the FAME composition of rapeseed (ME2) and palm (MEl) biodiesels as well as the melting and crystallization onset and enthalpy. Methyl oleate and elaidate are the predominant FAMEs in MEl and ME2 at 53.2% and 57.1 %, respectively. For palm biodiesel, methyl palmitate was the next most abundant FAME (27.4 %), followed by methyl stearate (9.4 %) and methyl linoleate (6.4 %). Concerning the rapeseed biodiesel, methyl linoleate was the next most abundant FAME (24.5 %) after methyl oleate, followed by methyl linolenate (8.6%) and methyl palmitate (4.6%). Rapeseed biodiesel (ME2) has a higher amount of unsaturated fatty acids (UFA, 92 %) than palm biodiesel (UFA, 61 %). The total saturated fatty acid (SEA) content for palm ester was 38 %, and 7 % for rapeseed ester. 

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