کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
64843 48372 2015 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Carbon monoxide-ethene copolymerization catalyzed by [PdCl2(dppb)] in H2O–H(CH2)nCOOH (dppb = 1,4-bis(diphenyphosphino)butane; n = 0, 1, 2)
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Carbon monoxide-ethene copolymerization catalyzed by [PdCl2(dppb)] in H2O–H(CH2)nCOOH (dppb = 1,4-bis(diphenyphosphino)butane; n = 0, 1, 2)
چکیده انگلیسی


• CO-ethene copolymerization.
• Catalyst [PdCl2(dppb)] in H2O–H(CH2)nCOOH (n = 0,1,2).
• High productivity and MW¯v.
• Kinetic equations.
• Solid state NMR.

[PdCl2(dppb)] is highly active in the catalytic CO-ethene copolymerization in H2O–H(CH2)nCOOH (n = 0, 1 or 2). The influence on the productivity, the limiting viscosity number and the average viscosity molecular weight MW¯v of the following reaction conditions is investigated: (i) solvent composition; (ii) temperature; (iii) CO and ethene partial pressure at a given pressure of one monomer; (iv) monomers ratio at a given total pressure; (v) total pressure at CO/ethene = 1/1; (vi) reaction time. The productivity passes through a maximum with a H2O molar fraction of 0.55–0.70 (14,800 gPK(g Pd h)−1 in H2O–HCOOH, H2O molar fraction = 0.58, 45 bar, CO/ethene = 1/1, 90 °C; LVN = 0.48 dLg−1, MW¯v = 21,194 Da). The productivity is in the order of the strength of the acid n = 0 > n = 1 > n = 2, whereas the activation energy is in the opposite order. These findings suggest that the protonation of the resting states β- and ɣ-chelate rings destabilizes them, thus favoring the chain-growing process. Proposed power rate laws fit the productivity data obtained at different monomer pressures. The productivity lowers with time, but in the first hour the rate remains almost constant. The morphology and crystallinity of selected PKs determined by solid state NMR is also discussed.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Catalysis A: Chemical - Volume 410, 15 December 2015, Pages 202–208
نویسندگان
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