Detail of "585-71-7"

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Are there covalent active species in the polymerization of styrene initiated by trifluoromethanesulfonic acid?

Are there covalent active species in the polymerization of styrene initiated by trifluoromethanesulfonic acid?. Matyjaszewski, Krzysztof; Sigwalt, Pierre (Lab. Chim. Macromol., Univ. Pierre et Marie Curie, Paris 75230, Fr.). Makromol. Chem., 187(10), 2299-316 (English) 1986. CODEN: MACEAK. ISSN: 0025-116X. DOCUMENT TYPE: Journal CA Section: 35 (Chemistry of Synthetic High Polymers) Polymn. of styrene [100-42-5] by HClO4 and F3CSO3H [1493-13-6] was assumed to proceed via a pseudo-cationic mechanism, but for the latter system the trifluoromethanesulfonate ester was not stable. Attempts to observe the model 1-phenylethyl ester were unsuccessful even at -78°. In the reaction between 1-phenylethyl bromide [585-71-7] and F3CSO3Ag [2923-28-6] a very rapid alkylation of the arom. rings occurred. In the reaction between 1-phenylethanol [98-85-1] and (F3CSO2)2O [358-23-6] a very rapid reaction between the intermediate ester (or ion) and the alc. led to the formation of the corresponding ether [93-96-9]. A reaction carried out with the optically active alc. indicated that ￡4% of the intermediate species might have reacted with the alc. as ester before racemization (i.e. ionization). The macromol. ester did not seem to be much more stable and in 19F NMR spectra only the acid was obsd. An attempt at the formation of a block copolymer with N-tert-butylaziridine gave zero or very low yields, contrarily to results previously obsd. with HClO4. An anal. of some former results on polymn. kinetics and of the new data obtained showed no real evidence in favor of the pseudo-cationic polymn. of styrene in CH2Cl2, initiated by CF3SO3H. The various data could be explained more satisfactorily by a more classical ionic mechanism. Triflic acid could reversibly protonate olefins due to the affinity of the triflate anion being higher for a proton than for a secondary or tertiary carbon atom; this was sufficient to explain the extremely low concn. of ionic species.

Nitroxide mediated polymerization of acrylate using new alkoxyamine initiators

All Rights Reserved. Nitroxide mediated polymerization of acrylate using new alkoxyamine initiators. Xia, Qing; Grubbs, Robert B. (Department of Chemistry and Center for Nanomaterial Research, Dartmouth College, Hanover, NH 03755, USA). Polymer Preprints (American Chemical Society, Division of Polymer Chemistry), 47(1), 194-195 (English) 2006 American Chemical Society, Division of Polymer Chemistry. CODEN: ACPPAY. ISSN: 0032-3934. DOCUMENT TYPE: Journal; (computer optical disk) CA Section: 35 (Chemistry of Synthetic High Polymers) Two novel alkoxyamine initiators for nitroxide-mediated radical polymns. were prepd. and evaluated in the polymn. of n-Bu acrylate: 2,2-dimethyl-3-(1-phenylethoxy)-4-phenyl-3-azapentane and 2,2-dimethyl-3-(1-phenylethoxy)-4,5-diphenyl-3-azahexane. The initiators were prepd. by reacting 1-bromoethylbenzene and 2-nitroso-2-methylpropane dimer or N-tert-Bu-a-phenylnitrone in the presence of N,N,N',N',N''-pentamethyldiethylenetriamine and CuBr/Cu in toluene. Decompn. 585-71-7 and 9003-49-0 which are cas registry numbers of chemicals are mentioned. of azapentane initiator was studied at different temps. by ESR. The effect of preheating the azapentane initiator (60-125°) on outcome of n-Bu acrylate polymn. was investigated. Preheating of initiator resulted in lower polydispersity of poly(Bu acrylate). .