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Ketene trimers, cyclic

Cyclic ketene trimers from cyclic ketene dimers... [Pg.464]

Cyclic ketene trimers from cyclic ketene dimers. Tetramethyl-l,3-cy-clobutanedione added during 0.5 hr. at 110° to a stirred suspension of some Na-methoxide in toluene whereupon the temp, rises gradually to 118°, refluxed 0.5 hr., cooled to 90°, a little more Na-methoxide added, and refluxing at 118° resumed for 0.5 hr. hexamethyl-1,3,5-cyclohexanetrione. Y 97.5%. [Pg.467]

Formaldehyde is a strong electrophile, allowing acetal to polymerize by nucleophilic, anionic, or cationic addition of an alcohol to ketene carbonyl groups. Relatively weak bases such as pyridine initiate anionic addition polymerization cationic addition polymerization is catalyzed by strong acids. When the cyclic trimer trioxane is used as a copolymer to polymerize acetal copolymers, Lewis acids such as boron tiifluoride promote copolymerization. A more fundamental description is polymerization of an aldehyde or ketone -l- alcohol -i- an acid or base catalyst to form hemiac-etal, which further converts to acetal. The hemiacetal reaction is reversible to aldehyde and alcohol. [Pg.81]

At 26.7 mbar pressure 40% weight toss main product is 2,4-diphenyl thiophene at least 11 unidentified minor products CO2, H2O, butene, isobutene, dimethyl ketene, styrene, methacrylic acid, succinic-type 5-membered cyclic anhydrides Chlorotrifluoroethylene, styrene, HQ, chloropentafluoropropene, ethene, chloroethene, totuene, a-melhylstyiene, dimer and trimer structures with some unsaturation S1F4 (fiom reaction of HF with glass). Distribution of products varies with polymer composition CO, CO2, propene, isobutene, dimethyl ketene, acrolein, allyl alcohol, toluene, styrene, cl-methylstyrene, ethylbenzene, glycidol, glycidylmethacrylate product distribution depends on copolymer composition... [Pg.497]


See other pages where Ketene trimers, cyclic is mentioned: [Pg.219]    [Pg.118]    [Pg.11]    [Pg.627]   


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Cyclic ketene

Cyclic trimerization

Ketenes, cyclic

Trimeric

Trimerization

Trimers

Trimers cyclic

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