Ether, historical perspective

Arylene ether/imide copolymers were prepared by the reaction of various amounts 4,4 -carbonylbis[Ar-(4 -hydroxyphenyl)phthalimide] and 4,4 -biphenoi with a stoichiometric portion of 4,4 -dichlorodiphenyl sulfone in the presence of potassium carbonate in NMP/CHP [55]. To obtain high molecular weight polymer, the temperature of the reaction was kept below 155 °C for several hours before heating to >155°C in an attempt to avoid undesirable side reactions such as opening of the imide ring. The imide ring is not stable to conditions of normal aromatic nucleophilic polymerizations unless extreme care is exercised to remove water. Special conditions must be used to avoid hydrolysis of the imide as previously mentioned in the section on Other PAE Containing Heterocyclic Units and as practiced in the synthesis of Ultem mentioned in the Historical Perspective section. 

A number of good reviews of the oxidation of phenols have appeared " the most recent covers the literature to mid-1980. These offer historical perspective and coverage of the biosynthetic aspects of the area, both inappropriate in the present article. This chapter focuses entirely on synthetic uses of the reaction and sets out (i) to survey the main types of reaction stemming from oxidation of phenols and phenol ethers and (ii) to offer selected examples of reactions showing satisfactory yield and regioselectivity. 

FORMULA D. Tri(hydroxyphenylene)methane triglycidyl ether 1. Historical perspectives... 

Snyder, F. 1999. The ether lipid trail a historical perspective. Biochim. Biophys. Acta 1436 265-278. 

Calixarenes Synthesis and Historical Perspectives, p. 1.53 Cation-n Interactions, p. 214 Crown Ethers, p. 326... 

Laudan asks whether, as a matter of historical fact, successful past theories always possess referring terms in the sense generally taken by realists. He provides numerous examples to show that this has generally not been the case. For example, Laudan cites several ether theories and other influential theories from the eighteenth and nineteenth century, like phlogiston and caloric, which were successful but possessed non-referring central terms from a modern perspective. Laudan does not however venture to make such an argument for any twentieth century theories or even less for any currently accepted theories in science. 

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