Chemicals from Fatty Acids

Fatty acids are often described by numbers such as 16 0, 18 1 or 18 3. The first number (16 or 18) is used to describe the number of carbon atoms in the chain whilst the second (0,1,3) gives the number of C=C double bonds in the molecule. Palmitic acid can therefore be shortened to 16 0 whilst oleic acid is 18 1 

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. 

Whilst the acids and many of their derivatives currently find niche applications in the market sectors identified above, factors related to price, volume of supply and consistency have all limited commercial viability. In the longer term, reduced costs and improved consistency through improved growing and harvesting techniques, coupled with an increased requirement for biodegradability, will increase demand for fatty acids. 

By way of a specific example let us consider erucic acid. The main commercial source of erucic acid is a specially bred form of rape seed (HEAR) as pointed out above. With European consumption being around 60 000 tpa almost 40 000 ha of land are used to grow rapeseed for erucic acid production in Europe. The high level of erucic found in this type of rape seed oil make it unsuitable for human consumption, owing to the indigestibility of such large amounts of this acid. Erucic acid is also the major fatty acid to be found in nasturtium and crambe seeds (up to 75% and 56% respectively), and it is also found in the salad herb, rocket. 

Linolenic acid is also important industrially it is the major constituent of linseed oil (approximately 47%) which is obtained from flax. The high degree of unsaturation present in this acid makes the oil an excellent drying agent for use in paints, varnishes and inks. 

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Apart from fatty acids, straight-chain molecules containing other hydrophilic end groups have been employed in numerous studies. In order to stabilize LB films chemical entities such as tlie alcohol group and tlie metliyl ester group have been introduced, botli of which are less hydrophilic tlian carboxylic acids and are largely unaffected by tlie pH of tlie subphase. 

Measurement of Unsaturation. The presence of double bonds in a fatty acid side chain can be detected chemically or through use of instmmentation. Iodine value (IV) (74) is a measure of extent of the reaction of iodine with double bonds the higher the IV, the more unsaturated the oil. IV may also be calculated from fatty acid composition. The cis—trans configuration of double bonds may be deterrnined by infrared (59) or nmr spectroscopy. Naturally occurring oils have methylene-intermpted double bonds that do not absorb in the uv however, conjugated dienes maybe deterrnined in an appropriate solvent at 233 nm. 

Originally isolated from the prostate gland (hence the name pro sta-gland-in), prostaglandins are chemically simple fatty acid-like molecules (Figure 5.3). Structural differences give rise to several series of structurally different prostaglandins, for example PGE, PGF and thromboxane. 

Esters are common components in cosmetics and skin-care products. They can be synthesized from fatty acids and alcohols using either chemical or enzymatic reactions. The chemical reactions are normally catalysed by acid catalysts. Enzymatic synthesis is carried out under milder conditions and therefore it provides products of very high purity. A range of esters such as isopropyl palmitate and isopropyl myristate are now produced industrially using enzymatic synthesis. The reactions are carried out in solvent-free systems using an immobilised lipase as catalyst. In order to get high yields in the reactions, water is removed continuously. 

Fatty amines are those containing alkyl groups having more than six carbon atoms. The commercial fatty amines are synthesized from fatty acids that occur in nature and are used as chemical intermediates. Other major uses of fatty amines and their derivatives include textile chemicals (particularly fabric softeners), emulsifiers for petroleum and asphalt, and flotation agents for ores. 

Stearyl Monoglyceridyl Citrate occurs as a soft, off white to tan, waxy solid having a lardlike consistency. It is prepared by a controlled chemical reaction from citric acid, monoglycerides of fatty acids (obtained by the glycerolysis of edible fats and oils or derived from fatty acids), and stearyl alcohol. It is insoluble in water, but is soluble in chloroform and in ethylene glycol. 

Chemical oxidation reactions and Strecker degradation of amino acids may also result in aldehyde formation (16). These reactions are important for the formation of acetaldehyde in baked or heated Sherries. Chemical oxidation reactions catalyzed by metal ions (Cu, Fe, Mn, Mo) can result in aldehyde production in oak aged distillates (20). Such reactions may also result in the formation of oxidation products from fatty acids released during the secondary fermentation of sparkling wines (21). 

Carbohydrates are introduced into the Krebs cycle at the point where pyruvate dehydrogenase catalyzes conversion of pyruvate to acetyl-Co A with the concomitant reduction of NAD. Citrate synthase catalyzes introduction of the 2-carbon unit of acetyl-CoA into the Krebs cycle. Pyruvate can arise from glucose, fructose, lactate, alanine, and glycerol. Acetyl-CcjAcan arise from pyruvate, as well as from fatty acids. Oxidation of fatty acids results in production of acetyl-Co A, which enters the Krebs cycle at the point catalyzed by citrate synthase. Breakdown of ketogenic amino adds also results in the production of acctyl-CoA, which enters the Krebs cycle at this point. Citrate and malate occur in high cor centrations in certain fruits and vegetables. These chemicals directly enter the Krebs cycle at the indicated points. 

Instead of being a triacyl ester of glycerol, the fat substitute olestra is a mixture of hexa-, hepta-, and octaacyl esters of sucrose in which the acyl groups are derived from fatty acids. Olestra has many of the physical and taste properties of a fat but is not metabolized by the body and contributes no calories. For more about olestra, see the April 1997 issue of the Journal of Chemical Education, pp. 370-372. 

Keasling, J.D. (2012) Design of a dynamic sensor-regulator system for production of chemicals and fuels derived from fatty acids. Nat. Biotech-nol., 30, 354-359. 

Assume that there is a pipeline whose age is 5 years with a downtime of 1 week. Biocide is routinely used in this pipeline. The pigging frequency in this pipe is 13 weeks. The fluid is stagnant, its temperature is 30°C, and both field and laboratory tests have confirmed the existence of mesophilic SRB. There is debris on the bottom of the pipe. Chemical analysis results are as follows Total dissolved solid (TDS) > 60 g/L, sulfate < 10 mg/L, total carbon from fatty acids < 20 mg/L, nitrogen (as utilizable N) < 5 mg/L, C-N ratio < 10, and prolonged oxygen ingress > 50 ppb. 

From the chemical view, plant oils are triacylglycerols, i.e., triesters from longer chain acids. Fatty acids constitute for some 95% of the total weight of triglycerides. Efficient routes to degradable and non-degradable renewable pol5mers from fatty acids have been summarized (67). 

A major portion of the petroleum used today is derived from lipids of plants deposited in past eons. The structures of most compounds isolated from petroleum suggest a derivation from fatty acids. Various chemical changes have occurred, mostly reduction and decarboxylation, so that most petroleum is comprised of a mixture of odd- and even-chain-length hydrocarbons. Some petroleums have a variety of other compounds that appear to be derived from chemical modification of other types of secondary metabolites. 

M.S. Collins Chemical Defense Secretions of the Termite Soldiers of Acorhino-termes and Rhinotermes (Isoptera, Rhinotermitinae) Ketones, Vinyl Ketones and P-Ketoaldehydes Derived from Fatty Acids. J. Chem. Ecol. 8,147-161 (1982). 

Vertebrate hormones hormones of vertebrate animals. On the basis of studies on the phylogenetic relationships of certain proteins, proteohormones and peptide hormones, the separate classification of V.h and Invertebrate hormones (see) appears to be justified. Chemically, V.h. are a heterogeneous group, which can be subdivided into Steroid hormones (see), hormones derived from amino acids (see Thyroxin, Adrenalin, Melatonin), Peptide hormones (see), Proteohormones (see), and hormones derived from fatty acids (see Prostaglandins). There is, however, no fundamental difference between V.h. and invertebrate hormones, with respect to types of chemical structure, or biochemical mode of action. 

Prestwich, G. D. and Collins, M. S. (1982) Chemical defense secretions of the termite soldiers of Acorhinotermes and Rhinotermes (Isoptera, Rhinotermitidae) ketones, vinyl ketones and p-ketoaldehydes derived from fatty acids. J, Chem, EcoL, 8, 147-61. 

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