Monomer ketone-substituted

Researchers at Du Pont used hydroquinone asymmetrically substituted with chloro, methyl, or phenyl substituents and swivel or nonlinear bent substituted phenyl molecules such as 3,4- or 4,4 -disubstituted diphenyl ether, sulfide, or ketone monomers. Eor example,... 

The a-oxygen-substituted hydroperoxides and dialkyl peroxides comprise a great variety as shown in Figure 1. When discussing peroxides derived from ketones and hydrogen peroxide, (1) is often referred to as a ketone peroxide monomer and (2) as a ketone peroxide dimer. 

Aryl radicals are produced in the decomposition of alkylazobenzenes and diazonium salts, and by f)-scission of aroyloxy radicals (Scheme 3.73). Aryl radicals have been reported to react by aromatic subsitution (e.g. of Sh) or abstract hydrogen (e.g. from MMA10) in competition with adding to a monomer double bond. However, these processes typically account for <1% of the total. The degree of specificity for tail vs head addition is also very high. Significant head addition has been observed only where tail addition is retarded by sleric factors e.g. methyl crotonate10 and -substituted methyl vinyl ketones 79, 84). 

Reaction of 1 with 4-fluorobenzoyl chloride yielded the difluoro-containing monomer 2, which is readily polymerized with a bisphenol using potassium carbonate in /V, /V-dimethy 1 acetamide to yield poly(ether ketone)s. The five poly-(ether ketone)s prepared were soluble in polar aprotic solvents and were cast into flexible, creasable films showing good thermal stability. We have demonstrated that 1 -phenoxy-substituted naphthalene moieties undergo a Friedel-Crafts acyla-... 

Over the past decade, literally dozens of new AB2-type monomers have been reported leading to an enormously diverse array of hyperbranched structures. Some general types include poly(phenylenes) obtained by Suzuki-coupling [54, 55], poly(phenylacetylenes prepared by Heck-reaction [58], polycarbosilanes, polycarbosiloxanes [59], and polysiloxysilanes by hydrosilylation [60], poly(ether ketones) by nucleophilic aromatic substitution [61] and polyesters [62] or polyethers by polycondensations [63] or by ring opening [64]. 

Miller et al. [87,88] have described the synthesis of hyperbranched aromatic poly(ether-ketone)s based on monomers containing one phenolic group and two fluorides which were activated towards nucleophilic substitution by neighboring groups. The molecular weight and polydispersity of the formed po-ly(ether-ketone)s could be controlled by reaction conditions such as monomer concentration and temperature. The formed polymers had high solubility in common solvents such as THF. 

Several different nucleophilic substitution reactions have been observed in the polymerization of methyl methacrylate. Attack of initiator on monomer converts the active alkyl-lithium to the less active alkoxide initiator (Eq. 5-75). Further, methyl methacrylate (MMA) is converted to isopropenyl alkyl ketone to the extent that this reaction occurs. 

The resulting polymerization is a copolymerization between the two monomers, not a homopolymerization of MMA. More importantly, this results in a slower reaction (and lower polymer molecular weight) since the carbanion derived from the ketone is not as reactive as the carbanion from MMA. Nucleophilic substitution by intramolecular backbiting attack of a... 

Willow-like cascade construction was facilitated by the preparation of the AB2-type building blocks, e.g., 6-bromo-l-(4-hydroxy-4 -biphenylyl)-2-(4-hydroxyphenyl)hexane (40 Scheme 6.12), 13-bromo-l-(4-hydroxyphenyl)-2-[4-(6-hydroxy-2-naphthalenylyl)-phenyljtridecane (41), and 13-bromo-l-(4-hydroxyphenyl)-2-(4-hydroxy-4"-p-terpheny-lyl)tridecane (42). Scheme 6.12 illustrates the monomer preparative strategy for the incorporation of the monomeric mesogenic moieties predicated on conformational (gauche versus anti) isomerism. Thus, one equivalent of 4-hydroxybiphenyl was allowed to react with 1,4-dibromobutane to yield the monobromide 43, which was converted under Finkelstein conditions to the corresponding iodide 44. Treatment of the latter with ketone 45 under phase transfer conditions afforded the a-substituted ketone 46. Reduc-... 

If one wishes to prepare a positive photoresist it is important to obtain polymers vdiich undergo efficient chain scission in the solid phase. Recently we reported studies on a series of copolymers of styrene with a variety of ketone functional groups which were introduced by copolymerization with substituted vinyl ketone monomers. The copolymer structures are shown schematically in Table V. Two processes are responsible for the reduction in molecular weight in these polymers when irradiated with either UV light or electron beams. These are shown schematically below. 

Similar information is available for other bases. Lithium phenoxide (LiOPh) is a tetramer in THF. Lithium 3,5-dimethylphenoxide is a tetramer in ether, but addition of HMPA leads to dissociation to a monomer. Enolate anions are nucleophiles in reactions with alkyl halides (reaction 10-68), with aldehydes and ketones (reactions 16-34, 16-36) and with acid derivatives (reaction 16-85). Enolate anions are also bases, reacting with water, alcohols and other protic solvents, and even the carbonyl precursor to the enolate anion. Enolate anions exist as aggregates, and the effect of solvent on aggregation and reactivity of lithium enolate anions has been studied. The influence of alkyl substitution on the energetics of enolate anions has been studied. ... 

The thermal characterization of 3,4 - and 4.4 -dicarboxy diphenyl ether containing polyesters has shown better thermal-stability than the corresponding 3,4 - and 4,4 -dicarboxy diphenyl ketone polyesters. Furthermore, higher degrees of substitution with the kinked monomer is necessary in case of the ketone containing polyesters to achieve the same depression of the melt transitions, compared to the ether polyesters. Crystalline-nematic transitions may be as low as approx. 200°C. 

IMI has also developed a general route for the synthesis of homo- and hetero-disubstituted benzophenones such as 4,4 -difluorobenzophenone (DFBP), 4,3 -di-fluorobenzophenone, and 4,4 -diphenoxybenzophenone (DPOBP). These substituted benzophenones are important materials, with a variety of uses as specialty monomers (for polyether ketones and polyarylene ether ketones) and pharmaceutical intermediates. These benzophenones are prepared by utilizing Heck technology in conjunction with an oxidative cleavage reaction. 

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