MOLECULAR SIEVE 4A - BULK AND DESSICANT BAGS

The discovery of the molecular sieve was in 1756 when the term zeolite was used for the first time, to describe a solid material of which the part of water could be removed by heating.  

The term molecular sieve has its origin JW McBain and defines a porous solid material that has the property to act as a sieve at the molecular level.  

This is a class of adsorbent which has the ability to retain certain molecules within its pores. Ideally, it has small pores distributed evenly. It has therefore a large surface area.  

The various proposed molecular sieve are:   

3A (pore size 3 Å) adsorbs NH3, H2O, (not C2H6), good for drying polar liquids.   

4A (pore size 4 Å) adsorbs H2O, CO2, SO2, H2S, C2H4, C2H6, C3H6, EtOH. Does not adsorb C3H8 and longer carbon chains. Good for drying nonpolar liquids and gases.   

5A (pore size 5 Å) adsorbs normal carbon chains (linear) type n-C4H10, C4H9OH type C4H9SH type alcohols and thiols. Do not adsorbs isomers or larger cyclic compounds that C4.   

10X (pore size 8 Å) adsorbs branched carbon chains and the aromatic rings. Useful for dry gas.   

13X (pore size 10 Å) adsorbs di-n-butylamine (no tri-n-butylamine). Useful for drying HMPA.