Introduction and Nomenclature

Common pames, such as formic (ant) and butyric (butter) acids, are based on the natural source of tire fid. The positions of substituent groups are shown by Greek letters, x. p. y. 6, etc. Some have names rived from acetic acid, e.g.. (CHj), CCOOH and C(lH5CH2COOH are trimethylacetic acid and fienylacetic acid, respectively. Occasionally they arc named as carboxylic acids, e.g. 

To get the IUPAC name, find the longest chain of C s including the C from COOH, as shown below by a horizontal line. To get the derived name, find and name the groups attached to the a C  

W C HggH -ICH OOHl Benzylacetic acid, 3-Phenylpropanoic acid OH 

Problem 16.2 Name the following aromatic carboxylic acids. 

Problem 16.3 Account for the following physical properties of carboxylic acids, (a) Only RCOOH s with five or fewer C s are soluble in water, but many with six or more C s dissolve in alcohols, (b) Acetic acid in the vapor state has a molecular weight of 120 not 60. (c) Their boiling and melting points are higher than those of corresponding alcohols. -4 

A copolymer is defined in section L3.1 as a polymer built from more than one type of chemical unit, and in section 4.1.1 a distinction between random copolymers of the type 

It is useful to introduce a simple nomenclature in order to indicate fairly concisely the type of copolymer involved in any material, as follows  

There is a further category of polymers that are not copolymers in the sense that units of different types are chemically joined together, as in all the types considered so far, but consist of two interpenetrating networks (IPNs), one formed by each type of polymer. Thus the different types of polymer are constrained to coexist because the different types of chain would have to pass through each other for the polymers to segregate. 

The tendency considered in section 12.2 for polymers of different types to segregate applies for the true copolymers, i.e. excluding IPNs, just as it does to blends. If one component is a very minor component or if the polymer is a random copolymer, segregation does not generally take place, but in block copolymers in which the minor components form more than a certain proportion of the whole, segregation generally takes place in some range of temperatures. The important difference here is that 

It is not possible within the scope of the present chapter to consider all forms of copolymer and further attention is therefore largely restricted to linear block copolymers. 

Simple (symmetrical) ethers have the general formula R—O—R or Ar—O—Ar mixed (unsymmetri- 

Problem 14.2 Account for the following, (a) Ethers have significant dipole moments (=1.18 D). (b) Ethers have lower boiling points than isomeric alcohols, (c) The water solubilities of isomeric ethers and alcohols are comparable. d 

Problem 14.3 Specify and account for your choice of an alkoxide and an alkyl halide to prepare the following ethers by the Williamson reaction (a) C,H,OC(CH,), (6) (CH,),CHOCH,CH==CH,. A 

The 2° and 3° alkyl halides readily undergo E2 eliminations with strongly basic alkoxides to form alkenes. Hence, to prepare mixed ethers such as (a) and (b) the 1° alkyl groups should come from RX and the 2° and 3° alkyl groups should come from the alkoxide. 

Problem 14.4 Show how dimethyl sulfate, MeOSO.OMe, is used in place of alkyl halides in the Williamson syntheses of methyl ethers. M 

Although the presence of a single phosphorus-carbon linkage is sufficient for a compound to be classified as a carbophosphorus compound, examples are known of wholly C-coordinated P derivatives for most of the viable configurations in Table 6.1. 

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