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208590 Sigma-Aldrich

Molecular sieves, 4 Å

beads, 4-8 mesh

  • CAS Number 70955-01-0

  • Linear Formula Na12[(AlO2)12(SiO2)12] · xH2O

  •  MDL number MFCD00131613

  •  eCl@ss 32110204



Related Categories Adsorbents, Filter Aids and Drying Agents, Essential Chemicals, Molecular Sieves, Research Essentials
Quality Level   100
form   beads
particle size   4-8 mesh
pore size   4 Å


General description

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.


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


1 kg in poly bottle

5 kg in fiber drum

500 g in poly bottle

Safety & Documentation

Safety Information

GHS07  GHS07
Signal word 
Hazard statements 
Precautionary statements 
Target organs 
Respiratory system
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


Certificate of Analysis (COA)

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Certificate of Origin (COO)

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Protocols & Articles

Related Content

Particle Size Conversion Table

Large sieve openings (1 in. to 1/4 in.) have been designated by a sieve "mesh" size that corresponds to the size of the opening in inches. Small sieve "mesh" sizes of 3 1/2 to 400 are designated by t...

Peer-Reviewed Papers


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