208590

Molecular sieves, 4 Å

beads, 4-8 mesh

• Fórmula lineal: Na₁₂[(AlO₂)₁₂(SiO₂)₁₂] · xH₂O
• Número de CAS: 70955-01-0
• Número MDL: MFCD00131613
• Código UNSPSC: 23201100
• eCl@ss: 32110204
• NACRES: NA.21

Propiedades

• Formulario: beads
• Nivel de calidad: 100
• tamaño de partícula: 4-8 mesh
• tamaño de poro: 4 Å

Descripción

Descripción general

Choosing a Molecular Sieve:
1. The preferential adsorption of one molecule over another depends upon pore diameter and mesh size.
2. The dynamic capacity of the silica gel for adsorbing a particular compound is governed by the internal surface area; the greater the surface area, the greater the dynamic capacity.
3. Rate of adsorption and sharpness of resolution are dependent chiefly on particle size and column packing; a fine particle size gives optimum sharpness of resolution.
4. Liquids are most readily adsorbed from solvents in which they are least soluble; a good solvent makes a good desorbing agent.
5. Highly polar liquids are readily adsorbed. Compounds having hydroxyl groups, or containing oxygen are strongly adsorbed.
6. For similar compounds, the higher the molecular weight the higher the selectivity.
7. For hydrocarbons of similar molecular weight, adsorptivity increases with the number of double bonds.

Regeneration or Activation:
A saturated molecular sieve can be restored to its original capacity by regeneration, the principle of which involves changing the conditions surrounding the adsorbent to correspond to a very low equilibrium capacity. In general, the greater the difference between the equilibrium capacities of adsorption and regeneration, the more rapid and complete the regeneration.
The sieve may be regenerated in one of four ways:
1. Thermal reactivation –The maximum regeneration temperature for Silica is 300°C.
2. Pressure reactivation
3. Passing an appropriate fluid through the gel bed at normal temperature and pressure.
4. Displacement of adsorbates by passing a high concentration of molecules in a fluid through the bed.

Aplicación

The product (Molecular sieves, 4 Å) has been used for the drying of HPLC grade acetonitrile.[1]

Información de seguridad

• Código de clase de almacenamiento: 13 - Non Combustible Solids
• Clase de riesgo para el agua (WGK): WGK 3
• Punto de inflamabilidad (°F): Not applicable
• Punto de inflamabilidad (°C): Not applicable