Unsaturated Unsaturation

Maleic anhydride itself has few, if any, consumer uses but its derivatives are of significant commercial interest (161). The distribution of end uses for maleic anhydride is presented in Table 9 for the year 1992 (182). The majority of the maleic anhydride produced is used in unsaturated polyester resin (see Polyesters, unsaturated). Unsaturated polyester resin is then used in both glass-reinforced appHcations and in unreinforced appHcations as shown in Table 10 (183). 

Degree of unsaturation. Unsaturation accounts for the existence of carbon-carbon double bonds in resins. It is generally indicated by the bromine or iodine number. Both methods are based on the halogen addition to the double carbon-carbon bonds. Because the different reactivity of bromine and iodine, both numbers cannot be compared. The bromine or iodine number does not necessarily correlate with the reactivity of the resin, for instance in the ageing process. However, within a given resin series of the same structure, relative comparisons can be made. 

Consequences of unsaturation. Unsaturation in the macrocyclic ring may have major steric and electronic consequences for the nature of the ring. Extensive unsaturation will result in loss of flexibility with a corresponding restriction of the number of possible modes of coordination. Further, loss of flexibility tends to be reflected in an enhanced macrocyclic effect . For example, if the metal ion is contained in the macrocyclic cavity, the loss of flexibility reduces the possible pathways for ligand dissociation and this tends to increase the kinetic stability of the system. As explained in later chapters, enhanced thermodynamic stabilities will usually also result. 

Fatty acids can then be classified by their degree of unsaturation as well as their chain length. Thus, fatty acids are either saturated if they have no double bonds or unsaturated. Unsaturated fatty acids are further subdivided into monounsaturated diunsaturated and so on. Fatty acids with many double bonds are classed as polyunsaturated. Table 3 gives the approximate fatty acid compositions of several fats and oils, Table 4 lists the unsaturated fatty acids found in milk (note the very wide diversity). 

Within each class the phospholipids can have alkyl chains of different length (Table 13.1) and different numbers of double bonds. Alkyl chains which only consist of single bonds are called saturated . Alkyl chains which contain at least one double bond are called unsaturated . Unsaturated alkyl chains are more flexible and have lower melting temperatures. 

If there are one or more double bonds in a hydrocarbon, it is unsaturated. Unsaturated, straight-chain hydrocarbons with one double bond are called alkenes. Their names are identical to the alkanes, except they end with ene instead of ane. An example is shown in Figure 1.8. If there are two double bonds, the chain is called an alkadiene, and the names end in adiene, instead of ene. An example is given in Figure 1.9. 

Fatty acids with no carbon-carbon double bonds are said to be saturated those with at least one double bond are unsaturated. Unsaturated fatty acids with more than one carbon-carbon double bond are referred to as polyunsaturated. Two... 

The terms saturated and unsaturated refer directly the to the chemistry definition of unsaturation. Unsaturated fats contain carbon-carbon double bonds (units of unsaturation), while saturated fats have only completely saturated carbon chains. Saturated fats (like butter and lard) stack together well in the solid state, so they are generally solid at room temperature. The double bonds in unsaturated fats disrupt this lattice in the solid state, making these types of fats (like olive oil and vegetable oil) liquid at room temperature. 

Synonyms Poiyester resin, unsaturated Poiyester, unsaturated Unsaturated poiyester resin UPR... 

Synonyms Polyester resin, unsaturated Polyester, unsaturated Unsaturated polyester resin UPR... 

Permanganate Test Baeyer Test for Unsaturation. Unsaturation in an organic compound can be detected by the decolorization of permanganate solution. The reaction involves the ds hydroxylation of the alkene to give a 1,2 diol (glycol) ... 

Pre-treatments for rubbers have been developed on an empirical basis but some scientific studies of successful pre-treatments have been undertaken. Methods for different rubbers will be reviewed in Section 1.2.3. Rubbers will be considered in groups, namely hydrocarbons that possess little unsaturation, unsaturated hydrocarbons, halogenated rubbers and miscellaneous materials. 

Hydrocarbons that do not contain the maximum amount of hydrogen are referred to as unsaturated. Unsaturated hydrocarbons are hydrocarbons in which not aii carbon atoms have four singie covaient bonds. An unsaturated hydrocarbon has one or more double bonds or triple bonds. Carbon atoms can easily form double and triple bonds to other carbon atoms, so multiple bonds between carbon atoms are common in organic compounds. 

Another commercially important reaction is du Font s synthesis of 1,4-hexa-diene. This is converted to synthetic rubber by copolymerization with ethylene and propylene, which leaves the polymer with unsaturation. Unsaturation is also present in natural rubber, a 2-methylbutadiene polymer 12.13, and is necessary for vulcanization. 

Hydrocarbons are organic compounds composed of carbon and hydrogen. Those that contain only C—C single bonds are saturated and are called alkanes, and those with carbon-carbon multiple bonds are unsaturated. Unsaturated hydrocarbons can become saturated by the addition of hydrogen, halogens, and/or other substituents. 

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