Saturated carbon atoms

Fatty Acids Fatty acids are long-chained carboxylic acids. Although their name includes the word fatty, fatty acids are not the same as fats. Fats are triglycerides, and fatty acids are one component of triglycerides. Naturally occurring fatty acids always have an even number of carbon atoms. Saturated fatty acids have carbon chains that contain only carbon-carbon single bonds. Unsaturated fatty acids have carbon chains that contain at least one carbon-carbon double bond. Monounsaturated fatty acids have one carbon-carbon double bond in the... 

Fatty acids are especially important and ubiquitous lipids. Apart from their use as fuel, they may be used in the synthesis of many other kinds of molecules. A fatty acid is a hydrocarbon chain with a terminal —COOH group. Usually, fatty acids contain between 14 and 25 carbons, 16 and 18 being most common. Unsaturated fatty acids are those that contain double bonds between some carbon atoms. Saturated fatty acids contain only single bonds. Palmitic acid (16) and stearic acid (Cl8) are particularly common saturated fatty acids in humans. Linoleic acid (Cl8), linolenic acid (Cl8) and arachidonic acid (C20) are common polyunsaturated fatty acids ( poly meaning more than one double bond). The number of carbons typically is even, reflecting the fact that fatty acid chains are built up (and broken down) in units of 2 carbon atoms at a time. 

The bile acids cholic acid and chenodeoxycholic acid are synthesized from cholesterol in the liver (Dl, S3). Several structural modifications are necessary to convert cholesterol, with its 27 carbon atoms, C-5,6 double bond and 3p-hydroxyl group, to a 24-carbon atom, saturated, 3,7 and 12a-hydroxyl-ated bile acid. The major reactions in this transformation are shown in Figs. 3 and 4. The reactions are catalyzed by mitochondrial, microsomal, soluble, and possibly peroxisomal enzymes. 

The chlorides of indium are of considerable historical interest. Kekul regarded valency as a fundamental property of the atom, as unchangeable and invariable as the atomic weight. This view he retained to the last. Apparent exceptions certainly existed. Carbon monoxide could, however, readily be explained on the assumption that the two unused valencies of the carbon atom saturate each other mercurous salts, such as the chloride, possessed the double formula, Cl-Hg-Hg-Cl, and so on. In 1888, however, Nilson and Pettersson showed that three distinct chlorides of indium can exist in the vapour state. To these they gave the formulas InCl, InCl2 and... 

Chemical Saturation Absence of double or triple bonds in a chain organic molecule such as that of most polymers, usually between carbon atoms. Saturation makes the molecule less reactive and polymers less susceptible to degradation and cross-linking. Also called Chemically Saturated Structure. 

In biomedical science, fatty acids have been investigated as carriers or for the development of drug delivery systems as they are considered to be endogenous, cost-effective and biocompatible. Stearic acid is a long-chain of 18 carbon atoms saturated fatty acid atoms which is the main component of fat. Initially, it was used for candle production. 

RNA (ribonucleic acid) Long chainlike molecules that occur throughout cells and take part in the construction of proteins, salt An ionic compoimd that usually remains dissolved in a solution after an acid-base reaction has occurred, salt bridge An inverted, U-shaped tube containing a strong electrolyte completes the circuit in an electrochemical cell by allowing the flow of ions between the two half-cells, saturated fat A triglyceride composed of saturated fatty acids. Saturated fat tends to be solid at room temperature, saturated hydrocarbon A hydrocarbon that contains no double or triple bonds between the carbon atoms, saturated solution A solution that holds the maximum amoimt of solute imder the solution conditions. If additional solute is added to a saturated solution, it wiU not dissolve, scientific law A statement that summarizes past observations and predicts future ones. Scientific laws are usually formulated from a series of related observations. 

Saturated hydrocarbons are hydrocarbons that contain only single bonds between the carbon atoms. Saturated hydrocarbon molecules can be cyclic or acyclic. A cyclic hydrocarbon is one in which a chain of carbon atoms has formed a ring. An acyclic hydrocarbon is one that does not contain a ring of carbon atoms. 

Hydrocarbons are grouped mainly by the type of bonding between carbon atoms. Saturated hydrocarbons are hydrocarbons in which each carbon atom in the molecule forms four single covalent bonds with other atoms. 

Carbon Chain The atomic structure of hydrocarbons in which a series of carbon atoms, saturated by hydrogen atoms, form a chain. Volatile oils have shorter chains. Fats have longer chain lengths, and waxes have extremely long chains. 

Policosanol is the common name for a mixture of highmolecular weight (12-36 carbon atoms) saturated aliphatic primary alcohols, which are constituents of plant epicuticular waxes, such as the common alcohols cetyl alcohol (Cjg), ceryl alcohol (Cjg) and myricyl alcohol (Cjq) (3-40). The cuticular wax of wheat, for example, contains lignoceryl alcohol (C24), ceryl alcohol ( 2 )... 

The double bonds in unsaturated fatty acids are almost always cis. Example State the number of carbon atoms, saturated or unsaturated, and name of the following ... 

Answer 16 carbon atoms, saturated, palmitic acid... 

There have been few detailed studies of the fatty acid compositions of echinids, but these animals often have high levels of polyunsaturated acids, particularly arachi-donic acid (20 4n-6) and EPA (20 5n-3). They also contain several non-methylene interrupted dienoic acids (NMIDs) in which the double bonds are not separated by a methylene (Joseph, 1989, pp. 90-100), but the most original finding may be that of a series of 2-hydroxy acids with 22, 23 or 24 carbon atoms, saturated and mono-unsaturated (n-9). Table 26.4 shows the major fatty acids (>1%) of Strongylocentrotus droebachiensis (Joseph, 1989) and Tripneustes esculentus (Carballeira, Shalabi, and Reyes, 1994). 

We shonld also utilize liquid hydrocarbons, which frequently accompany natural gas. These so-called natural gas liquids currently have little use besides their caloric heat value. They consist mainly of saturated straight hydrocarbons chains containing 3-6 carbon atoms, as well as some aromatics. As we found (Chapter 8), it is possible by superacidic catalytic treatment to upgrade these liquids to high-octane, commercially usable gasoline. Their use will not per se solve our long-... 

The simplest case is the substitution of a halogen at a saturated carbon atom by an alkyl group. Organocopper reagents exhibit strong carbanionic capacity, and do attack ester groups only slowly (D.E. Bergbreiter, 1975). Ketones, however, should be protected. The relative re-... 

The hydrogenolyaia of cyclopropane rings (C—C bond cleavage) has been described on p, 105. In syntheses of complex molecules reductive cleavage of alcohols, epoxides, and enol ethers of 5-keto esters are the most important examples, and some selectivity rules will be given. Primary alcohols are converted into tosylates much faster than secondary alcohols. The tosylate group is substituted by hydrogen upon treatment with LiAlH (W. Zorbach, 1961). Epoxides are also easily opened by LiAlH. The hydride ion attacks the less hindered carbon atom of the epoxide (H.B. Henhest, 1956). The reduction of sterically hindered enol ethers of 9-keto esters with lithium in ammonia leads to the a,/S-unsaturated ester and subsequently to the saturated ester in reasonable yields (R.M. Coates, 1970). Tributyltin hydride reduces halides to hydrocarbons stereoselectively in a free-radical chain reaction (L.W. Menapace, 1964) and reacts only slowly with C 0 and C—C double bonds (W.T. Brady, 1970 H.G. Kuivila, 1968). 

Univalent radicals derived from saturated unbranched alkanes by removal of hydrogen from a terminal carbon atom are named by adding -yl in place of -ane to the stem name. Thus the alkane... 

Bivalent radicals derived from saturated unbranched alkanes by removal of two hydrogen atoms are named as follows (1) If both free bonds are on the same carbon atom, the ending -ane of the hydrocarbon is replaced with -ylidene. However, for the first member of the alkanes it is methylene... 

Alternatively one chain radical may abstract a proton from the penultimate carbon atom of the other, giving one saturated and one unsaturated dead chain ... 

Amyl alcohol describes any saturated aliphatic alcohol containing five carbon atoms. This class consists of three pentanols, four substituted butanols, and a disubstituted propanol, ie, eight stmctural isomers four primary, three secondary, and one tertiary alcohol. In addition, 2-pentanol,... 

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