Polyketones, preparation

TABLE 2. Selected Aromatic Polyketones Prepared by Dehydration of a-Phenyl Acetic Acid Using Phosphorus Pentoxide and Methane Sulfonic Acid"... 

TABLE 1. Selected aromatic polyketones prepared according to the present invention. 

Ttihaloacyl aromatics have been prepared by Friedel-Crafts acylation of aromatics with CX COCl (X = Cl, Br) in the presence of AlCl. They are used as monomers in the preparation of polycarbonates, polyesters, polyamides, polyketones, and polyurethanes (91). 

An important direct use of phosgene is in the preparation of polymers. Polycarbonate is the most significant and commercially valuable material (see Polycarbonates). However, the use of phosgene has been described for other polymer systems, eg, fiber-forming polymeric polyketones and polyureas (90,91). 

The Suzuki reaction was also used to prepare the polyketone since this particular reaction tolerates the subsequent step (Scheme 6.19).135 Palladium-catalyzed cross-coupling of aromatic diacid chlorides and bis(trimethylstannane) monomers was utilized to prepare poly(arylene ether ketone)s.136... 

Since 1985, several thousands of publications have appeared on complexes that are active as catalysts in the addition of carbon monoxide in reactions such as carbonylation of alcohols, hydroformylation, isocyanate formation, polyketone formation, etc. It will therefore be impossible within the scope of this chapter to review all these reports. In many instances we will refer to recent review articles and discuss only the results of the last few years. Second, we will focus on those reports that have made use explicitly of coordination complexes, rather than in situ prepared catalysts. Work not containing identified complexes but related to publications discussing well-defined complexes is often mentioned by their reference only. Metal salts used as precursors on inorganic supports are often less well defined and most reports on these will not be mentioned. 

Aliphatic iodine derivatives, 14 376 Aliphatic ketones, 14 563, 571, 581-585 reactions of, 16 331-332 Aliphatic monothiopolyesters, 23 739 Aliphatic nitration, 12 187 Aliphatic peroxyacids, 13 464 Aliphatic peroxycarboxylic acids, 18 463 Aliphatic phosphines, 19 60 Aliphatic polyamides (PA), 10 207-210 19 713, 739. See also Aromatic polyamides PA entries producers of, 10 210 properties of, 10 208, 209t Aliphatic polycarbonates, 24 703 preparation of, 19 798 Aliphatic polyketones (PK), 10 197 costs of, 10 222 properties of, 10 198t Aliphatic poly(monosulfide)s, 23 702-704 Aliphatic polyphosphonate dyes, 9 480 Aliphatic poly(polysulfide)s, 23 711 Aliphatic polysulfides, 23 734 Aliphatic polysulfoxides, 23 733 miscibility of, 23 735 Aliphatic polyurea preparation, carbonyl sulfide in, 23 625... 

Although sequential B-oxidation from the carboxyl end of fatty acids was believed to be the mechanism for their breakdown, other schemes had been proposed, notably by Hurtley in 1915, who suggested multiple alternate oxidation—this idea was not widely accepted because the probable intermediates, polyketonic or polyunsaturated fatty acids, had never been detected. The abnormally high levels of acetoacetate produced by various liver preparations, however, caused multiple... 

In an earlier investigation by the author (1), polymeric ketones, (II), were prepared at ambient temperature by acid dehydration of a-phenyl acetic acid using phosphorus pentoxide and methane sulfonic acid as illustrated in Eq. (1). Aromatic polyketones formed from this process are provided in Table 2. 

Polynuclear complexes with more than two metal ions have been prepared with polyketone ligands but no such complexes have been reported with V02+. With the tetraketone l,l -(2,6-pyridyl)-bis-l,3-butanedione (H2L), several polynuclear complexes have been prepared including [(VO)2(L)2] for which jj,Tc = 1.21 BM was obtained.908... 

The preparation of various phenolic compounds has been accomplished from metbyl-enediisoxazole systems (74TL2793). Hydrogenation of (454) followed by acid treatment afforded a linear polyketone (456) which cyclized to the resorcinols (457) in good yield (55-80%) (Scheme 102). 

As pointed out in the introduction, because of the ease with which the carbonyl group can be chemically modified, the polyketones should be excellent starting materials for the synthesis of other classes of functionalized polymers. Indeed, a large number of derivatives of the C2H4—CO copolymer has been prepared and, not surprisingly, the vast majority of these are described in the patent literature. Patents concerning the use of these derivatives in polymer blends have also appeared but these are outside the scope of this review. 

Carboxidation of the poly-BD and other rubbers by nitrous oxide opens a simple and effective way for preparing polyketones with a regulated oxygen content and molecular weight. The presence of C=0 and C=C groups provides additional opportunities for application and modification of the material. 

Fluorinated phthalide 297 has been used to prepare polyketones such as 298, by polymerization with bisphenol A 299. This example has a glass transition temperature of 215 °C and forms strong transparent films. Remarkably, this is a polymerization based on an aromatic substitution reaction (SN2Ar) <1997MC210>. 

Polyketones containing indane structural units have been prepared by Friedel-Crafts acylation [Eq. (12)] [17]. However, oligomers and/or insoluble polymers were obtained. 

Other polymers of dimethylketone with a polyketone structure, .y. those prepared in the presence of trietbylamine, evidently do not undergo this d adation. 

In contrast to polyolefins such as polypropene, polyketones possess true stereo-genic centers along the polymer backbone. Therefore, poly ketones present a unique opportunity to use simple monomers in combination with chiral, enantio-merically pure palladium catalysts to prepare highly isotactic, optically active polymers (or oligomeric compounds) with main-chain chirality. 

As previously mentioned, the properties of olefm-CO copolymers depend strongly on the nature of the olefin employed. The glass transition temperature of 1-olefin-CO copolymers decreases from room temperature to nearly -60 °C upon increasing the chain length of the 1-olefin from propylene to 1-dodecene [33]. By contrast to polar ethylene-CO copolymers, copolymers with higher l-olefins display a hydrophobic character. For 1-olefin copolymerization, catalysts with entirely alkyl-substituted diphosphine hgands R2P-(CH2) -PR2 (R=alkyl, by comparison to R=Ph in dppp) such as 3 are particularly well-suited [48]. Efhylene-l-olefin-CO terpolymers and 1-olefin-CO copolymers can be prepared in aqueous polymerizations [43, 47, 48]. In the aforementioned copolymerization reactions, the polyketone was reported to precipitate during the reaction as a sohd [45, 47, 48, 50]. However, in the presence of an emulsifier such as sodium dodecyl sulfate (SDS) and under otherwise suitable conditions, stable polymer latexes can be obtained. 

A series of seven polyketones was prepared by Friedel-Crafts reaction nsing chloroanisole, chloroacetyl chloride, dichloroethane and dichloromethane with anhydrous alumininm chloride as catalyst and carbon disulphide as a solvent. Characterisation was nndertaken by determination of the chlorine content, IR spectroscopy, vapour pressure osmometry, TGA, and DSC. Antimicrobial properties are discnssed. 13 refs. 

The generation of homo- and copolymers prepared by Friedel-Crafts reactions of 2,7-bis [(2-ferroceneyl)methylene]cycloheptanone with various diacid chlorides has been reported.222 These polyketones were insoluble in most common organic solvents, but were quite soluble in concentrated H2S04. The homopolymers were thermally stable with two decompositions between 220 and 520°C, and the copolyketones showed decomposition at temperatures between 250 and 600°C. In both cases the first weight loss was determined to depend on the nature of the polymers and occurred at a faster rate than the second degradation. 

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