Mono-unsaturated

Preferential addition to one end or the other of a vinyl (CH2=CHX) or substituted vinyl (CH2=CXY) monomer seems to be the rule to which exceptions are rare. This generalization appears to apply to ionic as well as to free radical polymerizations. The polymers of mono-unsaturated compounds consequently are characterized by a high degree of head-to-tail regularity in the arrangement of successive units. Little is known concerning the sequence of d and I configurations of the asym-... 

Fig. 2 Action of desaturases and limited chain shortening can produce a variety of mono-unsaturated acyl-CoA precursors that can be modified to form unsaturated pheromone compounds. The arrow pointing down indicates limited chain shortening by two carbons. Modification of all 16-, 14-, 12-, and 10-carbon acyl-CoA derivatives on the carbonyl carbon can account for the majority of monounsaturated acetate esters, aldehydes, and alcohols identified as sex pheromones...

Poly(3HAMCL)s have also been produced from free fatty acid mixtures derived from industrial by-products which are potentially interesting low-cost renewable resources. Isolation and analysis of the polymer allowed the identification of 16 different saturated, mono-unsaturated and di-unsaturated monomers [46]. Except for the presence of diene-containing monomers and a large number of minor components, the composition of the fatty acid mixture derived PHA did not differ significantly from oleic acid derived PHAs. 

An example of the large variety of monomer structures present in poly(HAMCL) is given in Fig. 2. Also different degrees of unsaturation in poly(HAMCL) can be established relatively easily [3-5,34-39]. For example, the compositional data in Table 1 for the repeat units show that about 16% of the mono-unsaturated double bonds are incorporated when oleic acid is used as feedstock. When tall oil fatty acids are used, over 40 % of the subunits of the resulting poly(HAMCL) are mono- or di-unsaturated, while the total degree of unsaturation of the alkyl side chains of linseed oil-based PHA is even higher (>65%). Moreover, a substantial part (about 30%) of these unsaturated linseed oil-based poly(HAMCL) subunits have up to three double bonds present. 

Table 12.2 Some naturally occurring mono-unsaturated fatty acids...

What is the systematic name for a mono-unsaturated fatty acid containing 18 carbon atoms and a double bond at carbon 6 ... 

Buser, H.-R. Am, H. Guerin, P. Rauscher, S. Determination of Double Bond Position in Mono-Unsaturated Acetates by Mass Spectrometry of Dimethyl Disulfide Adducts. Anal. Chem. 1983, 55, 818-822. 

The mono-unsaturated disaccharide 74 was also prepared (4 ). It was obtained in 93% yield by condensation of 6g with 2,3,4,6-tetra-0-benzyl -et-D-qlucose under catalysis ( 7) with stannic chloride.Preliminary experiments indicated that it can likewise be oxyaminated (48). If this is borne out in further studies, a route would be open to the D-manno,D-gluco stereoisomers of and 57. 

Subsequent epidemiological studies have supported the association between better health and long-term consumption of diets rich in foods of plant origin. " However, whether this is because such diets minimize exposure to deleterious substances (e.g., oxidized cholesterol, pyrolysis mutagens, salt, saturated fat, etc.), or maximize intake of certain beneficial nutrients (e.g., isothiocyanates and other sulfur-containing plant constituents, mono-unsaturated fatty acids, and poly-unsaturated fatty acids, PPT, poly acetylenes, selenium, terpenes, etc.) or some combination as advocated in the Polymeal concept, remains unknown. " An in vitro study indicates that there may be mechanistic basis for true synergy between PPT and isothiocyanates. ... 

Among the sphingosine bases in the C. sandai sphingolipid mixture, a high content (44% of the total bases) of branched mono-unsaturated dihydroxy bases has been observed.159... 

The hardening effect of fatty oil isomerization processes is limited by the fact that cis-trans conversion of the double bond of mono-unsaturated fatty acids is an equilibrium reaction in the case of oleic and elaidic acid esters the equilibrium mixture consists of 67% elaidic acid and 33% oleic acid this equilibrium ratio is practically independent of the isomerization temperature77. 

As E. E. Sandmeyer stated, in general, diunsaturation increases the toxicity 4. This is also true, although with some exceptions, for mono-unsaturation. 

Lipids employed in the synthesis of double-tailed cationic lipids are typically saturated or mono-unsaturated linear hydrocarbons of between 12 and 18 carbon atoms long, often derivatives of oleic (C18 l), stearic (C18 0), palmitic (06 0) and myristic (04 0) acids being the most widely investigated [36-39]. 

Odor analysis (see Chapter 8) performed using GC coupled with olfactometry has also shown that many food items and household materials are odorant sources (Mayer and Breuer, 2006). Thus, mono-unsaturated aldehydes particularly E-2-nonenal are found in fat, wax, oil finish and lubricants branched aldehydes such as 3-methyl butanal are found in varnish, bread and malt while leather, rice and popcorn are sources of substituted pyrrolines especially 2-acetyl-l-pyrroline. Studies like this are important not only from the point of view of identifying sources of indoor odorants but also from the point view of providing vital information that can help consumers to select products. 

The same authors developed a process of encapsulation of polymers swelled by halogenated solvents in which ozone is greatly soluble but not monomers to be grafted. After ozonization of polymers swelled in solvents, mixtures of mono unsaturated or di unsaturated monomers are added to the activated polymers. Then, grafting is operated by UV irradiation. Grafting is mainly located at the surface of the starting polymer what prevents the modification of its intrinsic properties. This process permits to produce hydrophilic polysiloxanes used in medical applications (contact lenses, tubes, catheters, etc.). 

Hansen, H.J.M. (1987). Comparative studies on lipid metabolism in various salt-transporting organs of the European eel (Anguilla anguilla). Mono-unsaturated phosphatidyl ethanolamine as a key substance. Comparative Biochemistry and Physiology 88B, 323-332. 

Buser H. R, Arn H., Guerin P. and Rauscher S. (1983) Determination of double bond position in mono-unsaturated acetates by mass spectrometry of dimethyl disulfide adducts. Anal. Chem. 55, 818-822. 

Fig. 3. Structure of 1-stearoyl-2-oleoyl-3-phosphatidylcholine showing the saturated stearoyl (C18 0) and the mono-unsaturated oleoyl (C18 1) hydrocarbon chains. The hydrogen atoms surrounding the C=C bond are in the cis configuration.

Fig. 1. Structures of (a) a saturated fatty acid (palmitate, C16 0) (b) a mono-unsaturated fatty acid with the double bond in the cis configuration (palmitoleate, C16 1) (c) a mono-unsaturated fatty acid with the double bond in the trans configuration (C18 1) and (d) a polyunsaturated fatty acid (linoleate, C18 2).

Fatty acids are named according to the total number of carbon atoms, and to the number and position of any double bonds. The systematic names for fatty acids are made by adding oic acid on to the name of the parent hydrocarbon. However, as fatty acids are ionized at physiological pH they are usually written as RCOO", and have names ending in ate rather than oic acid. A C18 saturated fatty acid would be called octadecanoate, a C18 mono-unsaturated fatty acid octadecenoate, and a Cl 8 fatty acid with two double bonds octadecadienoate (see Fig. 1). However, many nonsystematic names are still in use (Table 1). 

From the isolation of the O-deacylated but otherwise unmodified GPL from serovar 12, it was also shown that the structure of the lipopeptide core was identical to that accepted for glycolipids of this group with respect to D-amino acid configurations, but not of the alaninol unit, and of the mono-unsaturated monohydroxy fatty acid.48... 

One important specific goal, even more challenging than the mono-unsaturation of alkanes in general, is the dehydrogenation of w-alkanes to give a-olefins (Eq. 1). 

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