- NEUTRAL LAYER POLYMER COMPOSITION FOR DIRECTED SELF ASSEMBLY AND PROCESSES THEREOF
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The present invention relates to a novel polymeric composition comprising a novel polymer having two or more repeat units and a terminus having the structure (1): wherein R1 represents a C1-C20 substituted or unsubstituted alkyl group, w is a number from 1-8, X is oxygen (O) or nitrogen (N), and Rd is a reactive group. The invention also relates to a process for forming a pattern using the novel polymeric composition. The invention further relates to a process of making the novel polymer.
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Page/Page column
(2014/01/08)
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- Effects of charge separation, effective concentration, and aggregate formation on the phase transfer catalyzed alkylation of phenol
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The factors that influence the rate of alkylation of phenol under phase transfer catalysis (PTC) have been investigated in detail. Six linear, symmetrical tetraalkylammonium cations, Me4N+, Et 4N+, (n-Pr)4N+, (n-Bu) 4N+, (n-Hex)4N+, and (n-Oct) 4N+, were examined to compare the effects of cationic radius and lipophilicity on the rate of alkylation. Tetraalkylammonium phenoxide·phenol salts were prepared, and their intrinsic reactivity was determined from initial alkylation rates with n-butyl bromide in homogeneous solution. The catalytic activity of the same tetraalkylammonium phenoxides was determined under PTC conditions (under an extraction mechanism) employing quaternary ammonium bromide catalysts. In homogeneous solution the range in reactivity was small (6.8-fold) for Me4N+ to (n-Oct) 4N+. In contrast, under PTC conditions a larger range in reactivity was observed (663-fold). The effective concentration of the tetraalkylammonium phenoxides in the organic phase was identified as the primary factor influencing catalyst activity. Additionally, titration of active phenoxide in the organic phase confirmed the presence of both phenol and potassium phenoxide aggregates with (n-Bu)4N+, (n-Hex)4N+, and (n-Oct)4N+, each with a unique aggregate stoichiometry. The aggregate stoichiometry did not affect the PTC initial alkylation rates.
- Denmark, Scott E.,Weintraub, Robert C.,Gould, Nathan D.
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supporting information; experimental part
p. 13415 - 13429
(2012/09/25)
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- Synthesis of biobased N-methylpyrrolidone by one-pot cyclization and methylation of γ-aminobutyric acid
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N-Methylpyrrolidone (NMP) is an industrial solvent that is currently based on fossil resources. In order to prepare it in a biobased way, the possibility to synthesize NMP from γ-aminobutyric acid (GABA) was investigated, since GABA can be obtained from glutamic acid, an amino acid that is present in many plant proteins. Cyclization of GABA to 2-pyrrolidone and subsequent methylation of 2-pyrrolidone to NMP was achieved in a one-pot procedure, using methanol as the methylating agent and a halogen salt (i.e. ammonium bromide) as a catalyst. A selectivity above 90% was achieved, as well as a high conversion. Methylation of 2-pyrrolidone could also be done with dimethyl carbonate, but then the selectivity for NMP was less (67%).
- Lammens, Tijs M.,Franssen, Maurice C. R.,Scott, Elinor L.,Sanders, Johan P. M.
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experimental part
p. 1430 - 1436
(2010/09/05)
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- Alkylation of ammonium salts catalyzed by imidazolium-based ionic liquid catalysts
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Quaternary ammonium salts were synthesized from ammonium salts and dialkyl carbonates over imidazolium ionic liquid catalysts. The reaction gave almost stoichiometric amounts of the quaternary ammonium salts for halides and nitrates. It was found that the electron-donating property of the alkyl moieties of ammonium cations, the electrophilic nature of the alkyl group of the carbonate, the acidity of the acid that the anion of the ammonium salt corresponds to, and the steric hindrance of the ammonium salts and the dialkyl carbonates are the key factors that influence the yields of quaternary ammonium salts. Strong electron-donating alkyl groups on the nitrogen atom of the ammonium salt, electron-withdrawing groups on the methylene carbon of dialkyl carbonate, and weaker steric hindrance of the starting ammonium salts and dialkyl carbonates favor the alkylation reaction of ammonium salts.
- Zheng, Zhuo Qun,Wang, Jie,Wu, Ting Hua,Zhou, Xiao Ping
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p. 1095 - 1101
(2008/03/27)
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- The synthesis of quaternary ammonium salts from ammonium salts and dialkyl carbonate
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Quaternary ammonium salts were synthesized from ammonium salts and dialkyl carbonates over an ionic liquid catalyst 1-ethyl-3-methylimidazolium bromide. The Royal Society of Chemistry 2006.
- Zheng, Zhuoqun,Wu, Tinghua,Zhou, Xiaoping
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p. 1864 - 1865
(2008/03/14)
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- Facile and scalable synthesis of imidazolium halides using dimethylmethyleneammonium salts as ring closing reagents
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An efficient procedure is proposed for the synthesis of 1,3-dialkylimidazolium salts starting from 1,4-diaza-1,3-dienes and methyleneammonium salts.
- Mistryukov, Electron A.
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p. 258 - 259
(2007/10/03)
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- Synthesis and in vitro enzyme hydrolysis of trioxadiaza- and tetraoxadiaza-crown ether-based complexing agents with disposable ester pendant arms
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New disposable ester derivatives of the complexing agents N,N′-bis(carboxymethyl)piperazine, -homopiperazine, -1,7-diaza-15-crown-5 and -1,10-diaza-18-crown-6 were synthesized with a variety of synthetic methods and fully characterized. Hydrolytic properties of the pendant arms were studied under different pH conditions as well as in the presence and absence of porcine liver esterase enzyme and approximate hydrolysis half lives were determined by 1H NMR technique. In vitro studies on pig liver cell homogenates and living thin chicken liver slices proved that the selected double ester 4b can penetrate liver tissues spontaneously, liberate the free complexing agent N,N′-bis(carboxymethyl)-18-ane-N2O4 (ODDA) inside the cells and are potentially capable of removing lead and other toxic metal ions from the liver. Georg Thieme Verlag Stuttgart.
- Ivanyi, Timea,Lazar, Istvan
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p. 3555 - 3564
(2007/10/03)
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- Structure and Stability of Quaternary Ammonium Interhalides: Experimental and Quantum-Chemical Study
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The electronic structure of a series of ammonium interhalides [R 1R2R3R4N]XI2, where R1 = CH3, C2H5, C3H 7, F, H; R2 = R3 = R4 = CH 3, H; X = Cl, Br, I, was studied by ab initio calculations (RHF/3-21G, RHF/HW, MP2/HW). The thermodynamic stability of these compounds correlates with the strength of the hydrogen bond N-H...X and three-center interhalide bond X-I-I. Calculations confirmed that, in polar solvents, these compounds preferably decompose to [R1R2R3R 4N]+ and XI2- (with subsequent decomposition of the anion), and in nonpolar solvents, to the neutral species [R1R2R3R4N]X and I2. The calculation results were compared to the experimental data obtained by single crystal X-ray diffraction, 1H NMR spectroscopy, and spectrophotometry.
- Simonyan,Kletskii,Chernov'yants,Gol'eva
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p. 575 - 582
(2007/10/03)
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- Photosensitive intramolecular electron transfer compounds
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A compound of the general formula: where A is a moiety which absorbs radiation and enters an excited state in which it accepts an electron; D- is a moiety which donates an electron to the excited state A and releases a free radical; and L+ is a cationic linking group which tethers electron acceptor moiety A to electron donor moiety D-. Cationic linking moiety L+ has the formula: where L' is a moiety which forms a stable radical with acceptor moiety A upon transfer of an electron from donor moiety D- to electron acceptor moiety A, and G is a moiety which forms a leaving group upon transfer of the electron from donor moiety D- to acceptor moiety A.
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- Esters of unsymmetrically 2-substituted glycolic acid dimers
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This invention concerns esters of unsymmetrically 2-substituted glycolic acid dimers, a process for their preparation and their use in the preparation of unsymmetrically 3,6-substituted 1,4-dioxane-2,5-diones.
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- Diphosphonic extractants
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New diphosphonic acid diesters in which the two phosphorus atoms are bound by a hydrocarbon group while each of the two acid functions of the diphosphonate is esterified by a radical having at least three carbon atoms are prepared by the treatment with a weak base of a corresponding tetramethyl diphosphonate, thereupon replacement of the cations of the base in the resultant disalt, by a radical R by means of a halide of said radical, and finally hydrolysis of the mixed diphosphonate thus obtained. The new compounds are suitable for various known uses of the different diphosphonates and in particular for the complexing of heavy metals; they are used in particular for the extraction of uranium and metals associated with it.
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- QUASIPHOSPHONIUM INTERMEDIATES. PART V. THE FORMATION OF ALKOXYPHOSPHONIUM INTERMEDIATES AND OF PHOSPHORUS-NITROGEN FISSION PRODUCTS IN REACTIONS OF NEOPENTYL N,N,N',N'-TETRAMETHYLPHOSPHORODIAMIDITE WITH HALOGENOMETHANES
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Alkoxyphosphonium halides are obtained as intermediates in the reactions of neopentyl N,N,N',N'-tetramethylphosphorodiamidite with chloro-, bromo-, iodo-methane.Whereas the iodide and bromide are well-defined crystalline solids, the chloride is low-melting and deliquescent.All are stable at room temperature and are hydrolysed only slowly.Thermal decomposition in deuterochloroform at 100 deg C gives neopentyl halides and methanephosphonic bisdimethylamide by SN2-type cleavage of the alkyl-oxygen bond.The presence of moisture may give rise also to the formation of dimethylammonium salts.In reactions of the phosphorodiamidite with bromo- or chloro-methane, competing quaternization at nitrogen and the formation of trimethylamine (and hence of tetramethylammonium halides) may be correlated with increasing hardness of the halide in the order I Br Cl.
- Hudson, Harry R.,Powroznyk, Luba,Qureshi, A. Rauf
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p. 289 - 296
(2007/10/02)
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