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US2873290A - Alkoxide synthesis - Google Patents

N2 - Alkali metal alkoxides are good catalysts (1-8 mol %) for promoting the interchange reaction between carbonyl and phosphorus esters. This reactivity leads to convenient methodologies for the synthesis of symmetric and unsymmetric alkyl-substituted methylphosphonates from dimethyl methylphosphonate (DMMP). Reactions rates are high with initial turnover frequencies (N(t)) in excess of 1 x 106 h-1 observed and with KO(t)Bu > NaO(t)Bu > LiO(t)Bu. The reactions were sensitive to steric effects in the product methylphosphonates with reaction rates paralleling the size of the transferring alkoxide (n-alkyl > isoalkyl >> tert-alkyl). For the test reaction DMMP + isopropyl acetate, substitution kinetics were consistent with a scenario wherein each methoxide is replaced sequentially, and the substitution rate for the second displacement is substantially slower than the first. Kinetic studies on the first substitution process were indicative of a concentration dependent rate law; a scenario most easily accounted for by a coupled transesterification wherein alkoxide reversibly and independently adds to phosphonate and ester.

25/10/2008 · Vanadium-lithium alkoxides: synthesis, ..

T1 - Synthesis and structural characterization of group 4 metal alkoxide complexes of N, N, N ′,N ′-tetrakis(2-hydroxyethyl)ethylenediamine and their use as initiators in the ring-opening polymerization (ROP) of rac -lactide under industrially relevant conditions

Alkoxide synthesis techniques for BaTiO3 - ScienceDirect

T1 - Synthesis of a double alkoxide precursor to spinel (MgAl2O4) directly from Al(OH)3, MgO, and triethanolamine and its pyroiytic transformation to spinel

Amorphous vanadium oxides were synthesized by the hydrolysis of tri-n-butoxy vanadyl, and three types of products, gel, green precipitates and red precipitates were obtained. These products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared absorption spectroscopy (IR), thermogravimetric-differential thermal analysis (TG-DTA) and chemical analysis. Properties of the products were correlated to the synthesis conditions, and the mechanisms of the formation of each product are proposed. (1) Gel has a network structure. It is formed when hydrolysis followed by condensation proceeds on three substitutional groups of tri-n-butoxy vanadile, (2) green precipitates are formed when the condensation reaction is inhibited. They are the aggregates of particles with small molecular weights and have short structure units with hydroxide groups at their ends, (3) red precipitates are caused by insufficient proceeding of hydrolysis. They have many alkoxy groups in their structure units and their molecular weights are between those of gels and green precipitates.

Synthesis of Amorphous Vanadium Oxide from Metal Alkoxide

AB - Alkali metal alkoxides are good catalysts (1-8 mol %) for promoting the interchange reaction between carbonyl and phosphorus esters. This reactivity leads to convenient methodologies for the synthesis of symmetric and unsymmetric alkyl-substituted methylphosphonates from dimethyl methylphosphonate (DMMP). Reactions rates are high with initial turnover frequencies (N(t)) in excess of 1 x 106 h-1 observed and with KO(t)Bu > NaO(t)Bu > LiO(t)Bu. The reactions were sensitive to steric effects in the product methylphosphonates with reaction rates paralleling the size of the transferring alkoxide (n-alkyl > isoalkyl >> tert-alkyl). For the test reaction DMMP + isopropyl acetate, substitution kinetics were consistent with a scenario wherein each methoxide is replaced sequentially, and the substitution rate for the second displacement is substantially slower than the first. Kinetic studies on the first substitution process were indicative of a concentration dependent rate law; a scenario most easily accounted for by a coupled transesterification wherein alkoxide reversibly and independently adds to phosphonate and ester.

N2 - Amorphous vanadium oxides were synthesized by the hydrolysis of tri-n-butoxy vanadyl, and three types of products, gel, green precipitates and red precipitates were obtained. These products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared absorption spectroscopy (IR), thermogravimetric-differential thermal analysis (TG-DTA) and chemical analysis. Properties of the products were correlated to the synthesis conditions, and the mechanisms of the formation of each product are proposed. (1) Gel has a network structure. It is formed when hydrolysis followed by condensation proceeds on three substitutional groups of tri-n-butoxy vanadile, (2) green precipitates are formed when the condensation reaction is inhibited. They are the aggregates of particles with small molecular weights and have short structure units with hydroxide groups at their ends, (3) red precipitates are caused by insufficient proceeding of hydrolysis. They have many alkoxy groups in their structure units and their molecular weights are between those of gels and green precipitates.

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,revealed by single crystal X-ray diffraction analysis

Alkali metal alkoxides are good catalysts (1-8 mol %) for promoting the interchange reaction between carbonyl and phosphorus esters. This reactivity leads to convenient methodologies for the synthesis of symmetric and unsymmetric alkyl-substituted methylphosphonates from dimethyl methylphosphonate (DMMP). Reactions rates are high with initial turnover frequencies (N(t)) in excess of 1 x 106 h-1 observed and with KO(t)Bu > NaO(t)Bu > LiO(t)Bu. The reactions were sensitive to steric effects in the product methylphosphonates with reaction rates paralleling the size of the transferring alkoxide (n-alkyl > isoalkyl >> tert-alkyl). For the test reaction DMMP + isopropyl acetate, substitution kinetics were consistent with a scenario wherein each methoxide is replaced sequentially, and the substitution rate for the second displacement is substantially slower than the first. Kinetic studies on the first substitution process were indicative of a concentration dependent rate law; a scenario most easily accounted for by a coupled transesterification wherein alkoxide reversibly and independently adds to phosphonate and ester.

/ Kissling, Rebecca M.; Gagné, Michel R

AB - Amorphous vanadium oxides were synthesized by the hydrolysis of tri-n-butoxy vanadyl, and three types of products, gel, green precipitates and red precipitates were obtained. These products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared absorption spectroscopy (IR), thermogravimetric-differential thermal analysis (TG-DTA) and chemical analysis. Properties of the products were correlated to the synthesis conditions, and the mechanisms of the formation of each product are proposed. (1) Gel has a network structure. It is formed when hydrolysis followed by condensation proceeds on three substitutional groups of tri-n-butoxy vanadile, (2) green precipitates are formed when the condensation reaction is inhibited. They are the aggregates of particles with small molecular weights and have short structure units with hydroxide groups at their ends, (3) red precipitates are caused by insufficient proceeding of hydrolysis. They have many alkoxy groups in their structure units and their molecular weights are between those of gels and green precipitates.

The English Language Book Society and Longman Group Ltd) ..

Amorphous vanadium oxides were synthesized by the hydrolysis of tri-n-butoxy vanadile, and three types of products, gel, green precipitates and red precipitates were obtained. These products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared absorption spectroscopy (IR), thermogravimetric-differential thermal analysis (TG-DTA) and chemical analysis. Properties of the products were correlated to the synthetic conditions, and the mechanisms of the formation of each product are proposed. (1) Gel has a network structure. It is formed when hydrolysis followed by condensation proceeds on three substitutional groups of tri-n-butoxy vanadile, (2) green precipitates are formed when the condensation reaction is inhibited. They are the aggregates of particles with small molecular weights and have short structure units with hydroxide groups at their ends, (3) red precipitates are caused by insufficient proceeding of hydrolysis. They have many alkoxy groups in their structure units and their molecular weights are between those of gels and green precipitates.

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