Dacron synthesis

Many molecules contain more than one function group (either the same or different). In such cases, condensation reactions involving two or more groups per molecule can lead to the formation of polymers, as mentioned above in the formation of proteins from amino acids (—NH2 and —COOH groups). From the standpoint of terminology, the unit or units that are joined together to produce a polymer are monomers with multiple units possible (dimer, trimer, etc.). An example of a man-made polymer involves the synthesis of polyester fiber, such as Dacron polyester on which the textile industry depends. 

Alcohols occur widely in nature. Methanol is also known as wood alcohol because it can be obtained by distilling wood in the absence of air. It is very poisonous and can cause blindness or death if ingested. Ethanol is consumed in alcoholic beverages. Other simple alcohols, such as 2-phenylethanol from roses and menthol from peppermint, are constituents of natural flavors and fragrances. Alcohols are important intermediates in chemical synthesis. They are also commonly used as solvents for various chemical processes. Ethylene glycol is used in antifreeze and in the preparation of polymers such as Dacron. 

The synthesis of step-growth polymers—polytimides such as nylon and Kevlar, polyesters such as Dacron, polyurethanes such as spandex, and polycarbonates such as Lexan (Section 30.6)... 

Use Synthesis of terephthalic acid for polyester resins and fibers ( Dacron, Mylar, Terylene ), vitamin and pharmaceutical syntheses, insecticides. 

The growth of synthetic fibers has led to the devising of syntheses from petroleum of the chemical intermediates required for this new industry. Leaving aside acetic anhydride from ethylene via synthetic ethanol and from propylene via acetone, already established and used for cellulose acetate in the 193O s, nylon has called for the isolation of petroleum cyclohexane and for the discovery of a route from butadiene to nylon salt Dacron for the isolation of p-xylene from petroleum xylene, and the nitrile fibers for the synthesis of acrylonitrile from ethylene or acetylene. 

The simplest aromatic carboxylic acid is benzoic acid. Derivatives are named by using numbers and prefixes to show the presence and location of substituents relative to the carboxyl group. Certain aromatic carboxylic acids have common names by which they are more usually known. For example, 2-hydroxybenzoic acid is more often called salicylic acid, a name derived from the fact that this aromatic carboxylic acid was finst obtained from the bark of the willow, a tree of the genus SaEx. Aromatic dicarboxylic acids are named by adding the words dicarboxylic acid to benzene. Examples are 1,2-benzenedicarboxyhc acid and 1,4-benzenedicar-boxylic acid. Each is more usually known by its common name phthahc acid and terephthalic acid, respectively. Terephthahc acid is one of the two organic components required for the synthesis of the textile fiber known as Dacron polyester (Section 16.4B). 

Aromatic dicarboxylic acids are named by adding the words dicarboxylic acid to benzene (e.g., 1,2-benzenedicarboxylic acid and 1,4-benzenedicarboxylic acid). Each is usually known by its common name phthalic acid and terephthalic acid, respectively. Terephthalic acid is one of the two organic components required for the synthesis of the textile fiber known as Dacron polyester, or Dacron (Section 29.5B). 

Bofh alkyl groups are oxidized to —COOH groups. The product is terephthalic acid, one of two monomers required for fhe synthesis of Dacron polyester and Mylar (Section 29.5B). 

Polyester is synthesized by the direct reaction of a diacid and a diol at high temperatures. An example is the synthesis of Dacron ... 

---