Video Experimental Relacionado
Updated: May 18, 2026
08:49
Organic Structure-directing Agent-free Synthesis for *BEA-type Zeolite Membrane
Published on: February 22, 2020
Polietileno funcionalizado con fosfonio: una nueva clase de membranas de intercambio de aniones alcalinas basales
Kevin J T Noonan1, Kristina M Hugar, Henry A Kostalik
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA.
Journal of the American Chemical Society
|September 29, 2012
Resumen
Un nuevo catión de fosfonio ofrece una estabilidad superior para las membranas de intercambio aniónico alcalino (AAEM). Este avance permite el desarrollo de materiales AAEM más duraderos para aplicaciones exigentes.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química de Polímeros La Química de Polímeros es la química de los polímeros.
- La electroquímica es electroquímica.
Sus antecedentes:
- Las membranas de intercambio de aniones alcalinos (AAEM) son cruciales para las aplicaciones electroquímicas.
- La estabilidad de los grupos funcionales en condiciones alcalinas severas es un desafío clave.
- Los cationes de tetraquis (dialquilamino) fosfonio representan una alternativa potencial a los grupos tradicionales de amonio.
Objetivo del estudio:
- Para evaluar la estabilidad básica de un catión tetráquico ((dialquilamino) fosfonio en comparación con un catión benciltrimetilamonio estándar.
- Para sintetizar y caracterizar nuevos AAEMs que incorporan este catión de fosfonio.
- Para evaluar el rendimiento y la estabilidad de estos nuevos AAEMs.
Principales métodos:
- Pruebas comparativas de estabilidad en soluciones alcalinas fuertes (NaOD/CD, 3OD y KOH).
- Síntesis de AAEMs basados en polietileno a través de la polimerización de la metátesis de apertura de anillo.
- Medición de la conductividad del hidróxido y su estabilidad a largo plazo en diversas condiciones.
Principales resultados:
- El catión tetráquico ((dialquilamino) fosfonio demostró una estabilidad básica significativamente mayor que el catión benciltrimetilamonio.
- Se prepararon con éxito nuevos AAEM que incorporan el catión fosfonio.
- Los AAEM desarrollados exhibieron una conductividad de hidróxido de 22 ± 1 mS cm(-1) a 22 °C.
Conclusiones:
- Los cationes tetráquicos (dialquilamino) de fosfonio son grupos funcionales altamente estables para las AAEM.
- Estos AAEM basados en fosfonio son prometedores para aplicaciones que requieren una alta estabilidad alcalina.
- Investigaciones adicionales pueden explorar la optimización para mejorar el rendimiento y aplicaciones más amplias.
Videos de Conceptos Relacionados
01:17Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...
01:15Potentiometry: Membrane Electrodes
Membrane electrodes, also known as p-ion electrodes, use membranes that selectively interact with free analyte ions, generating a potential difference across the membrane. The resulting membrane potential, known as the asymmetry potential, is not zero even when analyte concentrations on both sides of the membrane are equal. The membrane's response is typically not selective to a single analyte but proportional to the concentration of all ions in the sample solution capable of interacting at the...
01:22Phosphate Buffer
The phosphate buffer system is a critical biological mechanism for maintaining pH stability in the body. This system operates primarily through two components: sodium dihydrogen phosphate (NaH2PO4), which acts as a weak acid, and sodium hydrogen phosphate (Na2HPO4), which serves as a weak base.
Sodium dihydrogen phosphate does not fully dissociate in neutral or acidic solutions. When a strong base, such as sodium hydroxide (NaOH), is introduced into the solution, sodium dihydrogen phosphate...
Sodium dihydrogen phosphate does not fully dissociate in neutral or acidic solutions. When a strong base, such as sodium hydroxide (NaOH), is introduced into the solution, sodium dihydrogen phosphate...
01:21Basicity of Aliphatic Amines
Amines can behave as Brønsted–Lowry bases by accepting a proton from the acid to form corresponding conjugate acids. Due to a lone pair of nonbonding electrons, aliphatic amines can also act as Lewis bases by forming a covalent bond with an electrophile.
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
01:09Ion-Exchange Chromatography
Ion-exchange chromatography, or IEC, is a technique for separating ions based on their affinity for the stationary phase. The stationary phase is a cross-linked polymer resin with covalently attached ionic functional groups. The functional groups can be either positively charged (cation exchangers) or negatively charged (anion exchangers). A cation exchanger consists of a polymeric anion and active cations, while an anion exchanger is a polymeric cation with active anions. The choice of...
02:42Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.