Ketones polyketones

The selective formation of the 3-monosemicarbazones of polyketonic steroids can be achieved only in the presence of 21-acetoxy-20-ketones by the use of nonbuffered conditions. Partial hydrolysis of 3,20-bissemicar-bazones can be achieved with acetic anhydride in pyridine "" to yield the 3-semicarbazone. Kinetic studies on the rates of formation of Girard hydra-zones showed that the A" -3-ketone is less reactive than the saturated 3- and 6-ketones, as reactive as the 7- and 17-ketones and more reactive than the 20- and 12-ketones. ... 

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... 

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... 

The carbonylation of ethene has a wider interest as it can lead to the production not only of polyketones, but also to many other products ranging from low molecular weight cooligoesters, down to methyl propanoate (MP) and also cooligodiesters, cooligodiketones down to diethyl ketone (DEK). The insertion of the monomers into MeOH is schematized by Eq. 1, n ranging from 1 to even more that 10000 ... 

It has been known for some time that dimethylketene produces three different types of polymers with polyketonic (47, X = Y), polyacetalic, 48, and polyester, 49, structures (88-90) (Scheme 11). The use of nonsymmetric ketenes like methylisopropylketene should produce an iso-syndio stereoisomerism in the ketonic form (47, X Y, only one of the possible stereoisomers is shown) and an orientational isomerism in the polyacetalic form, 48 in the polyester form, 49, there would be a combination of the two possibilities, analogous to those described for polyallenes. 4-Methylpentamethyleneketene offers the reverse possibilities iso-syndio isomerism in the polyacetalic form, 50, orientational isomerism in the polyketonic form, 51, and the combination of the two in the polyester form, 52 (Scheme 12). The three polymeric forms (ester, acetal, ketone) of 2- and 3-methylpentamethyleneketene each show both of these types of isomerism, one along and the other perpendicular to the chain. 

Ethylene hydroformylation was treated as a separate case, as difSculties arise from dramatic changes in the IR spectrum of dissolved ethylene as a function of its partial pressure. This was overcome using the method of band-target entropy minimisation (BTEM, see Chapter 4) to recover the pure component spectra of all observable species and their concentrations [72]. As well as the conventional acyl tetra-carbonyl, [Rh(C(0)Et)(C0)4], evidence was obtained for [Rh(C(0)Et)(C0)3(C2H4)], containing coordinated ethylene. The presence of this species indicates that ethylene can compete with H2 for the unsaturated [Rh(C(0)Et)(C0)3]. The ketone and polyketone side products of Rh-catalysed ethylene hydroformylation arise from insertion of coordinated ethylene into the Rh-acyl bond in [Rh(C(0)Et)(C0)3(C2H4) ... 

The alcoholysis rate decreases by either increasing the steric bulk of the alcohol or decreasing its nucleophUicity (i.e., MeOH > EtOH > PrOH > BuOH 2,2,2-tri-fluoroethanol). Parallel to the decrease of the chain-transfer rate, the molecular weight of the copolymer increases. An effective role of water as hydrolysis agent in alcoholic media appears very unlikely as HOOC-terminated polyketone or oligo-ketone have never been observed. Obviously, in neat water, hydrolysis is a feasible chain-transfer path, leading to acid-terminated materials [13]. 

Aromatic polyketones are semicrystalline materials that contain both ketone groups generally flanked by aromatic units. Many also have within them ether moieties that allow for some flexibility and better processing. They have good thermal stabilities, as well as offering good mechanical properties, flame resistance, impact resistance, and resistance to the environment. 

Palladium-catalyzed a-arylation of ketones is performed with arylene dihalides and bifunctional aromatic ketones 148 to result in the bond formation at the r/) -a-carbon of the ketone, leading to polyketone 149. The reaction is carried out in the presence of Pd(0) and various phosphines. Several bidentate phosphines and bulky alkylphosphines such as dppf, BINAP, PCys, and P Bu3 are shown to be effective, while PPh3 results in no reaction. Arylene dibromide and diiodide are applicable as the co-monomers. The polymerization reaction is carried out in THE in the presence of NaO Bu at 75 °C under N2, and polymers 149 are isolated in 60-80% yields (M = 7000-15 000). Polyketone 149 is further transformed to conjugated polymer PPV by reduction of the ketone moiety with LiAlH4 followed by dehydration with an acid (Equation (69)). 

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. 

The polyketones may be structurally characterized by IR and NMR spectroscopy, as well as by X-ray crystal structure determinations. Saturated ketones have a characteristic strong IR absorption band at 1715 cm-1, and this band was observed for the... 

Olefin-carbon monoxide co-polymers of the type (-RCH-CH2-CO-)n, known as polyketones, have a wide variety of interesting properties, such as thermoplasticity, flexibility, durability and high impact strength. The ketone function in the polymer makes them sensitive to UV radiation and as a consequence they are photodegradable and hence environmentally acceptable plastics. However their light sensitivity has limited their applications. They can be made by the copolymerisation of an alkene with carbon monoxide (Equation 27 see also Chapter 7, Section 7.7) ... 

A potentially valuable characteristic of poly(ether-ketone-carborane)s is that they display enormously enhanced char-yields (up to 95% on pyrolysis in air), compared to the yields obtained from analogous all-aromatic polymers.7 This behaviour suggests that carborane-based polyketones such as 7 could eventually find application as fire-retardants and as precursor polymers for carbon-ceramic materials. 

Besides condensation reactions to form heavy ends, polyester ketones are formed by the decomposition of acetyl iodide to polyester polyketones (eq. (22)) following a mechanism similar to the decomposition of acetyl chloride [64d,ej. 

In early patents by Halcon, molybdenum carbonyls are claimed to be active catalysts in the presence of nickel and iodide [23]. Iridium complexes are also reported to be active in the carbonylation of olefins, in the presence of other halogen [24] or other promoting co-catalysts such as phosphines, arsines, and stibines [25]. The formation of diethyl ketone and polyketones is frequently observed. Iridium catalysts are in general less active than comparable rhodium systems. Since the water-gas shift reaction becomes dominant at higher temperatures, attempts to compensate for the lack of activity by increasing the reaction temperature have been unsuccessful. 

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. 

REACTION SYNTHESES OF KETONE ACID-ESTERS AND POLYKETONES WITH SODIUM AND SODIUM ALCOHOLATE... 

In place of the acid-ester in the above reaction, which is susceptible of many combinations, a ketone may be used a ketone acid-ester is not formed, it is true, but polyketones, or ketone-aldehydes ... 

In a patent filed as early as 1948, Reppe and Magin described the reaction of ethylene with carbon monoxide in the presence of an aqueous solution of potassium nickel(II) cyanide at 150°C and 150 bar [4], Along with propionic acid and diethyl ketone, higher molecular weight solid polyketones were obtained. The alternating copolymerization of alkenes with carbon monoxide has received continued industrial and academic interest, one reason being the low cost of carbon monoxide as a monomer [5],... 

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