Fittig s Reaction

Fittig s Reaction.—The most important reaction of the benzene halogen substitution products is what is known as Fittig s reaction, by means of which a paraffin chain may be substituted in the benzene ring, and benzene homologues prepared. 

The great number of hydrocarbons which may be prepared by Fittig s reaction is apparent from the above examples. The value of the reaction is still further increased by the fact that a halogen atom in the side-chain of an aromatic hydrocarbon also reacts in the same way. 

Cinnamic Acid.—The reaction, which takes place when an aldehyde (aliphatic or aromatic) acts on the sodium salt of an aliphatic acid in presence of the anhychide, is known as Perkin s reaction, and has a ery wide application. Accoid-ing to the result of Fittig s researches on the properties of the unsaturated acids described below, the reaction occurs in two steps. The aldeh) de forms first an additive compound with the acid, the aldehyde caibon attaching itself to the n-carbon ii.e.i nevt the carbovyl) of the acid. A saturated hydiOKy-acid is formed, which is stable, if the a-carbon is attached to only one atom of hydrogen, as in the case of isobutync acid,... 

Fittig s Synthesis.—When Kekule brought out his benzene theory the relation between toluene and benzene, the first two members of the homologous series of benzene hydrocarbons, was not known. It was worked out by Fittig and Tollens by means of what is known as the Fittig synthesis, which is based on a reaction exactly analogous to the Wurtz reaction for the synthesis of the homologous members of the aliphatic series of hydrocarbons. 

Fittig discovered diphenyl. He applied Wurtz s reaction (see p. 509) to the synthesis of aromatic hydrocarbons by the action of sodium on a mixture of an aryl and alkyl halide. Fittig synthesised mesitylene, showed that it is symmetrical trimethyl benzene, and investigated its oxidation, so discovering m-xylene and isophthalic acid. With J. H. Eaton he first prepared the complex salts K4Mn(CN)e and K3Mn(CN)6 in the solid form. ... 

Cinnamic acid was prepared from benzaldehyde and acetyl chloride by Bertagnini. Cinnamic aldehyde was synthesised by Chiozza from benzaldehyde, acetaldehyde, and hydrochloric acid, and on oxidation forms cinnamic acid. Perkin synthesised cinnamic acid by the action of acetic anhydride and sodium acetate on benzaldehyde. He thought an explanation of the reaction on the lines of Fittig s hypothesis ... 

While electrophilic substitution reactions enabled the direct functionalizations of (hetero)arenes, Fittig observed, during the nineteenth century, that halogenated arenes could be employed for the preparation of alkylated arenes in the presence of sodium under Wurtz s reaction conditions [24—26]. 

Rapson, W. S., Shuttleworth, R. G. Free aryl radicals In the FIttig and Ullmann reactions. Nature (London, United Kingdom) 1941,147, 675. 

Billow and Miller [187] also reported fairly similar results for poly(phenylene)s prepared from mixtures of terphenyls. Poly(m-phenylene) [188], phenyl-substituted polyphenylene [189] and perfluoropolyphenylene [190] have thermal and oxidative stabilities similar to that of poly(p-phenylene). Polyphenylenes synthesized by Wurtz-Fittig and Ullmann reactions were reported to withstand heating up to 500°-550°C [187,191,192]. Electrically conductive azo derivatives of polyphenylene (cTo= l-40ohm cm ) were stable up to 300°C without any noticeable decomposition, whereas the conductive block co-polymer of poly-phenylene with p-diethynylbenezene could withstand heating for many hours at 400°-450°C [I], Poly(p-phenylene) as well as poly(tetrafluoroethylene) have been reported to withstand a similar temperature without any thermal degradation and may be used safely up to similar... 

Fittig claimed that Perkin s results were due to the use of too high a temperature, and at about 100° the acid obtained corresponded with the salt used, irrespective of the anhydride. C. M. Stuart, another pupil of Fittig, found that, in presence of acetic anhydride, salts of malonic and isosuccinic acids, which do not form anhydrides, also condense with benzaldehyde. Fittig and Jayne, and Fittig and P. Ott, claimed to have obtained evidence of an addition product in the reaction ... 

The need for a thermally stable, solvent-resistant polymer was met by the use of a Wurtz-Fittig synthesis of polyphenylene sulfide. The need for an impact-resistant clear polymer was fulfilled by the reaction of phosgene and the sodium salt of bisphenol A. Admittedly, polymers of formaldehyde, which are found as a sediment in formalin bottles, was investigated by Nobel Laurate Hermann Staudinger in the 1920 s but this polymer lacked integrity until DuPont and Celanese chemists produced thermally stable, injection moldable polyoxymethylene. 

The first report of a polymeric acrylic ester was published in 1877 by Fittig and Paul [2] and in 1880 by Fittig and Engelhorn [3] and by Kahlbaum [4], who observed the polymerization reaction of both methyl acrylates and methacrylates. But it remained to O. Rohm [5] in 1901 to recognize the technical potential of the acrylic polymers. He continued his work and obtained a U.S. patent on the sulfur vulcanization of acrylates in 1914 [6]. In 1924, Barker and Skinner [7] published details of the polymerization of... 

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