Poly l -phenyl-2-

Since only Ta and Nb catalysts, which are not tolerant to polar groups, are available for the polymerization of disubstituted acetylenes, it is generally difficult to synthesize disubstituted acetylene polymers having such a highly polar substituent as a hydroxy group. Recently, synthesis of poly[l-phenyl-2-( -hydroxyphenyl)acetylene] has been achieved by the polymerization of 1-phenyl-2-(p-siloxyphenyl)acetylene and the subsequent acid-catalyzed deprotection reaction. 

Example 17 Syntheses of Poly l-phenyl-2-(p-r-butyldimethylsiloxyphenyl)-acetylene) and Poly l-phenyl-2-(p-hydroxyphenyl)acetylene ... 

Poly[l-phenyl-2-(/7- -butyldimethylsiloxyphenyl)acetylene] is solution cast to produce a membrane that is subsequently transformed into a durable membrane via desilylation using a mixture of trifluoroacetic acid (TFA)/water. A detailed method of desilylation of membranes is as follows the membrane of polymer is immersed in a mixture of TFA and water (9 1 v/v) at room temperature for 24 h. To neutralize the remaining acid in the polymer matrix, the membrane is then immersed in aqueous sodium carbonate solution at room temperature for 24 h, and then dried in air at room temperature. Finally, the membrane is immersed in hexane for 24 h to remove residual impurities and dried to constant weight at room temperature for 24 h. Complete desilylation is confirmed by IR speetroscopy (no absorptions are seen at 1250 d, Si-CH), 855 (Vas, Si-CHs), and 812 cm (Vas, Si-CHs), which are observed in the siloxy polymer). Desilylation is also confirmed by measuring the weight of the membrane before and after desilylation, thereby verifying loss of the silyl group e.g., mass of siloxy polymer = 53.6 mg, mass of hydroxy polymer = 33.5 mg (measured), 33.5 mg (calculated). ... 

Poly(l-phenyl-2- 4-[( 2-[l-(l,2,3,4,5-pentaphenyl)silolylJethynyl propyl)oxy]phenyl -acetylene) (4)... 

Poly(DPA) is, thermally, the most stable substituted polyacetylene, but it is insoluble in any solvent, and hence it is impossible to fabricate a membrane from it by solution casting. In order to prepare this polymer membrane, desilylation of poly[l-phenyl-2-p-(trimethylsilyl)phenylacetylene] (PTMSDPA) membrane has been examined by use of trifluoroacetic acid as catalyst in hexane. The desilylation reaction proceeds to completion, as evidenced by IR spectroscopy and the anticipated weight decrease (eqn [a] in Scheme 4). As expected, the poly (DPA) membrane produced is insoluble in any solvent and possesses high thermal stability. This polymer shows fairly high gas permeability irrespective of the absence of any spherical substituent, as described below. The pinanylsilyl-containing poly(DPA) in eqn [b] is soluble, membrane-forming, and CD-... 

Poly( l-phenyl-2,5-dioxopyrrolidin-3,4-diyl) PolyfN-phenylnudeimide]... 

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