Fatty acids direct hydrogenation

Localization of double bonds in unknown compounds has frequently been determined by ozonolysis. Unsaturated fatty acids of biological membranes are susceptible to ozone attack, but there are some important differences from autoxidation reactions. These include the fact that malonaldehyde is produced from linoleate by ozonolysis (53) but not autoxidation and also that ozonolysis does not cause double bond conjugation as judged by absorption at 233 nm (52). Reactions with the polyunsaturated fatty acids produce several possibilities for toxic reactions direct disruption of membrane integrity and toxic reactions caused by fatty acid hydroperoxides, hydrogen peroxide, and malonaldehyde. 

Identification Menhaden Oil can be differentiated from animal fats and vegetable oils by the distinctive significant amount of long-chain C20 and C22 fatty acids. Partially Hydrogenated Menhaden Oil exhibits the following typical composition profile of fatty acids, determined as directed under Fatty Acid Composition, Appendix VII ... 

The fatty acids obtained from the process can be used directly or further manipulated for improved or modified performance and stabiUty. Hardening is an operation in which some fraction of the unsaturated bonds present in the fatty acids are eliminated through hydrogenation or the addition of H2 across a carbon—carbon double bond. This process was initially intended to improve the odor and color stabiUty of fatty acids through elimination of the polyunsaturated species. However, with the growth in the use of specialty fatty acids, hydrogenation is a commercially important process to modify the physical properties of the fatty acids. 

Cocoa butter substitutes and equivalents differ greatly with respect to their method of manufacture, source of fats, and functionaHty they are produced by several physical and chemical processes (17,18). Cocoa butter substitutes are produced from lauric acid fats such as coconut, palm, and palm kernel oils by fractionation and hydrogenation from domestic fats such as soy, com, and cotton seed oils by selective hydrogenation or from palm kernel stearines by fractionation. Cocoa butter equivalents can be produced from palm kernel oil and other specialty fats such as shea and ilHpe by fractional crystallization from glycerol and selected fatty acids by direct chemical synthesis or from edible beef tallow by acetone crystallization. 

Direct Metal Reaction. The DMR process is carried out over a catalyst with fatty acids ia a melted state or dissolved ia hydrocarbons. The acid reacts directiy with the metal, suppHed ia a finely divided state, produciag the metal soap and ia some cases hydrogen. Catalysts iaclude water, aUphatic alcohols, and low molecular-weight organic acids. 

Compared with the fatty alcohol sulfates, which are also oleochemically produced anionic surfactants, the ester sulfonates have the advantage that their raw materials are on a low and therefore cost-effective level of fat refinement. The ester sulfonates are produced directly from the fatty acid esters by sulfona-tion, whereas the fatty alcohols, which are the source materials of the fatty alcohol sulfates, have to be formed by the catalytic high-pressure hydrogenation of fatty acids esters [9]. The fatty acid esters are obtained directly from the fats and oils by transesterification of the triglycerides with alcohols [10]. 

Some more recent processes have been developed which involve direct hydrogenation of the oil to the fatty acid and 1,2-propane diol. These high-temperature (>230 °C) and high-pressure processes generally use a copper chromium oxide catalyst. 

The plausible deoxygenation routes for production of diesel like hydrocarbons from fatty acids and their derivates are decarboxylation, decarbonylation, hydrogenation and decarbonylation/hydrogenation. The main focus in this study is put on liquid phase decarboxylation and decarbonylation reactions, as depicted in Figure 1. Decarboxylation is carried out via direct removal of the carboxyl group yielding carbon dioxide and a linear paraffinic hydrocarbon, while the decarbonylation reaction yields carbon monoxide, water and a linear olefinic hydrocarbon. 

Fir.. 7. Structure of dibasic fatty acid COOH 04H6 COOH. Long hydrogen bonded chains are formed in the c direction in the crystal... 

The presence of the double bond (carbonyl group C 0) markedly determines the. chemical behavior of the aldehydes. The hydrogen atom connected directly to the carbonyl group is not easily displaced. The chemical properties of the aldehy des may be summarized by (1) they react with alcohols, with elimination of H2O, to form ace t i (2) they combine readily with HCN to form cyanohydrins, (3) they react with hydroxylamine to yield aldoximes (4) they react with hydrazine to form hydrazones (5) they can be oxidized lulu fatty acids, which contain die same [lumber of carbons as in the initial aldehyde 5) they can be reduced readily to form primary alcohols. When bcnzaldchydc is reduced with sodium amalgam and HjO, benzyl alcohol C,f l - -C f I Of I is obtained. The latter compound also may be obtained by treating benzaldehyde with a solution of cold KOH in which benzyl alcohol and potassium benzoate are produced. The latter reaction is known as Cannizzaro s reaction. 

The direct hydrogenation to deoxidize fatty acid esters results in hydrocarbons with one carbon atom less than the number present in the hydrocarbon chain of the original ester. The reaction can be carried out quantitatively, but it is a relatively drastic chemical operation. In the Grignard method the hydrocarbon chain of the molecule is lengthened the reactions are executed at relatively low temperatures the overall yield amounts to 70-90% of the theory. 

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