Synthesis and ring‐opening polymerization of macrocyclic aromatic sulfide oligomers

Abstract

A series of macrocyclic(arylene sulfide) oligomers were synthesized by reaction of 4,4 -oxybis(benzenethiol) with a number of difluoro compounds in dimethylformamide (DMF) in the presence of anhydrous K 2 CO 3 under high dilution conditions. The difluoro compound can be 4,4 -difluorobenzophenone, bis(4-fluorophenyl)sulfone or 1,3-bis(4-fluorobenzoyl)benzene. Detailed structural characterization of these oligomers by matrix-assisted laser desorption and ionization-time of flight-mass spectroscopy (MALDI-TOF-MS) demonstrated their cyclic nature. The MALDI-TOF-MS technique has proved to be a powerful tool to analyze these cyclics. These cyclic oligomers are amorphous and highly soluble in DMF and N,N -dimethyl acetamide. Moreover, these cyclic(arylene sulfide) oligomers readily underwent ring-opening polymerization in the melt at 285 • C in the presence of 2,2 -dibenzothiazole disulfide, affording linear, high molecular weigh poly(aromatic sulfide)s. These polymers are insoluble in most common solvents.

Entropically Driven Ring-Opening Polymerization of Strainless Organic Macrocycles

“…MCOs 66 were obtained in 88% yield using a different approach, a highdilution Friedel−Crafts reaction between 4,4′-diphenoxybenzophenone and phthaloyl chloride catalyzed by aluminum trichloride. 88 Various types of sulfur-containing MCOs related to aromatic high-performance polymers have been prepared. The most common are similar to the ether ketones discussed above but with some of the ether groups replaced by thioether groups and/or ketone groups replaced by sulfone groups.…”

“…15,37,42,86,87 MCOs 72−74 were each obtained by reacting 4,4′-dithioldiphenyl ether with the appropriate difluoro compound. 88 MCOs 75 were obtained in 41% yield using a Friedel−Crafts reaction between 4,4′diphenoxydiphenyl sulfone and isophthaloyl chloride catalyzed by aluminum trichloride. 88 Gibson and co-workers have synthesized several macrocyclic monomers (or larger oligomers), related to high-performance aromatic polymers, by multistep syntheses of large linear building blocks, which are then used in cyclizations at high dilution.…”

“…The ED-ROP of 248 at >280 °C has been carried out using a DSC instrument. 188 Similar ED-ROPs afford polymers 254, 185 256, 88 and 257; 88 see Table 9, entries 4−6, respectively, and 251. 189 MCOs containing disulfide or polysulfide linkages, for example, 76 and 77, have also been polymerized.…”

Chemoenzymatic synthesis of poly(phenylene disulfides) with insulating properties and resistant to high temperatures

“…These molecules have been used as cross‐linking agents and precursors of high molecular weight polymers which are considered high temperature‐resistant materials . The main interest in CAD synthesis lies in their lower melting temperature (T m ) compared with the corresponding linear oligomers and their low melt viscosities which facilitates the process of melt ring opening polymerization (mROP) for the synthesis of PPD or PPS . Even more, the cycles can undergo ring opening polymerization without generation of any byproduct .…”

“…The synthesis of CAD has been reported using chemical agents as catalysts . Nevertheless, the chemical synthesis involves harsh reaction conditions and the use of strong agents; copper salts (mainly CuCl) and tetramethylethylenediamine (TEMED) have been used as catalysts in chemical synthesis of CAD, and the resultant CuCl‐TEMED complexes must be removed during the downstream process by strong acids such as HCl solutions, which are difficult to reuse.…”