Why is molecular sieve the best desiccant that money can buy? Molecular sieve, also known as synthetic alumina silicate is a unique adsorbent in that it has a very unique pore structure.  This product has been developed so that differentiation in actual pore openings can be  as small as one angstrom (1 angstrom = 1/1000 of a human hair).  It is by far the best choice in terms of desiccant for those companies looking to maintain the lowest possible relative humidity (RH).

Molecular sieves retain their ability to adsorb water vapor molecules over a much wider spectrum of temperatures as compared to other desiccant medias, and also have a much higher equilibrium capacity for water vapor under very low RH conditions.  Molecular sieves contain a uniform network of crystalline pores and empty adsorption cavities, which give it an internal adsorptive surface area of 700-800gm² (½ the total volume of the crystals). Due to its uniform structure, molecular sieves will not release any trapped water vapor back into the environment or package as readily as silica gel or clay as temperatures rise.

Unlike indicating silica gel which will turn from blue to pink as it becomes saturated with water vapor, indicating molecular sieve turns from blue to beige. The following is a helpful list of molecules that the various types of molecular sieves will adsorb:

3A:  NH3, H20, (not C2H6), good for drying polar liquids
4A:  H20, Co2, SO2, H2S, C2H4, C2H6, C3H6, EtOH.  Will not adsorb C3H8 and higher hydrocarbons.  Good for drying nonpolar liquids and gases
5A:  Adsorbs normal (linear) hydrocarbons to n-C4H10, alcohols to C4H9OH, mercaptans to C4H9SH.  Will not adsorb isocompounds or rings greater than C4
10X (pore size 8A):  Adsorbs branched hydrocarbons and aromatics.  Useful for drying gases
13X (pore size 10A):  Adsorbs di-n-butylamine (not tri-n-butylamine.  Useful for drying HMPA

Part Number Description 1 lb 5 lb 25 lb 55 lb
641A3MS55-13 (1 lb)
641A3MS55-13-5lb
641A3MS55-13-55lb
3A Non-indicating molecular sieve
1-3 mm bead diameter, 8x12 mesh
$19.95 $39.60 $95.40 $192.00
641A3MS55-35 (1 lb)
641A3MS55-35-5lb
641A3MS55-35-55lb
 3A Non-indicating molecular sieve
3-5 mm bead diameter, 4x8 mesh
$19.95 $31.00 $95.40 $192.00
641A4MS01 (1 lb)
641A4MS05 (5 lb)
641MS4A55 (55 lb)
4A Non-indicating molecular sieve
1mm bead diameter, 16x24 mesh
$21.50 $39.50 $95.40 $123.75
641A4MS55-13 (1 lb)
641A4MS55-13-5lb
641A4MS55-13-55lb
 4A Non-indicating molecular sieve
1-3 mm bead diameter, 8x12 mesh
$19.95 $35.20 $79.25 $163.00
641A4MS55-35 (1 lb)
641A4MS55-35-5lb
641A4MS55-35-55lb
 4A Non-indicating molecular sieve
3-5 mm bead diameter, 4x8 mesh
$19.95 $35.20 $79.25 $163.00
641A5MS55-13 (1 lb)
641A5MS55-13-5lb
641A5MS55-13-55lb
 5A Non-indicating molecular sieve
1-3 mm bead diameter, 8x12 mesh
$19.95 $37.25 $89.50 $192.00
641X13MS55-13 (1 lb)
641X13MS55-13-5lb
641X13MS55-13-55lb
 13X Non-indicating molecular sieve
1-3 mm bead diameter, 8x12 mesh
$19.95 $37.25 $89.50 $192.00
641X13MS55-35 (1 lb)
641X13MS55-35-5lb
641X13MS55-35-55lb
 13X Non-indicating molecular sieve
1-3 mm bead diameter, 4x8 mesh
$19.95 $37.25 $89.50 $192.00
641IMS05 (5 lb)
641IMS55 (55 lb)
4A Indicating molecular sieve
3-5mm bead diameter, 4x8 mesh
    - $87.10 $399.40 $735.65
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1 lb Can of 3A Non-Indicating Molecular Sieve; (8x12 mesh) - 641A3MS55-13
1 lb Can containing Non-indicating molecular sieve 3A (Ångströms) 1-3 mm bead diameter 8x12 mesh ..
$19.95
1 lb Can of 5 lb of 3A Non-Indicating Molecular Sieve; (8x12 mesh) - 641A3MS55-13
5 lb can of Non-indicating molecular sieve 3A (Ångströms) 1-3 mm bead diameter 8x12 mesh Allow..
$39.60
55 lb Drum of 3A Non-Indicating Molecular Sieve; (8x12 mesh) - 641A3MS55-13
55 lb drum of Non-indicating molecular sieve 3A (Ångströms) 1-3 mm bead diameter 8x12 mesh ..
$192.00
1 lb Can of 3A Non-Indicating Molecular Sieve; (4x8 mesh) - 641A3MS01-35
1 lb can of Non-indicating molecular sieve 3A (Ångströms) 3-5 mm bead diameter 4x8 mesh Allows..
$19.95
5 lb Can of 3A Non-Indicating Molecular Sieve; (4x8 mesh) - 641A3MS05-35-5lb
5 lb can of Non-indicating molecular sieve 3A (Ångströms) 3-5 mm bead diameter 4x8 mesh Allows..
$31.00
55 lb Drum of 3A Non-Indicating Molecular Sieve; (4x8 mesh) - 641A3MS55-35-55lb
55 lb Drum of Non-indicating molecular sieve 3-5 mm bead diameter 4x8 mesh Allows water va..
$192.00
1 lb Can of 4A Non-Indicating Molecular Sieve; (16x24 mesh) - 641A4MS01
1 lb. can NON-INDICATING molecular sieve 4A (Ångströms) 1mm bead diameter 16x24 mesh Ne..
$21.50
5 lb Can of 4A Non-Indicating Molecular Sieve; (16x24 mesh) - 641A4MS05
5 lb. can NON-INDICATING molecular sieve 4A (Ångströms) 1mm bead diameter 16x24 mesh Ne..
$39.50
55 lb Drum of 4A Non-Indicating Molecular Sieve - 641MS4A55
55 lb drum of 4A non-indicating molecular sieve  Purchase Above, or go back to Bulk Desiccan..
$123.75
1 lb Can of 4A Non-Indicating Molecular Sieve; (8x12 mesh)- 641A4MS55-13
1 lb can of Non-indicating molecular sieve 4A (Ångströms) 1-3 mm bead diameter 8x12 mesh Absor..
$19.95
5 lb Can of 4A Non-Indicating Molecular Sieve; (8x12 mesh) - 641A4MS55-13
5 lb can of Non-indicating molecular sieve 4A (Ångströms) 1-3 mm bead diameter 8x12 mesh Absor..
$35.20
55 lb Drum of 4A Non-Indicating Molecular Sieve; (8x12 mesh) - 641A4MS55-13
55 lb can of Non-indicating molecular sieve 4A (Ångströms) 1-3 mm bead diameter 8x12 mesh Abso..
$163.00
1 lb Can of 4A Non-Indicating Molecular Sieve; (4x8 mesh) - 641A4MS55-35
1 lb can of Non-indicating molecular sieve 4A (Ångströms) 3-5 mm bead diameter 4x8 mesh Absorb..
$19.95
5 lb Can of 4A Non-Indicating Molecular Sieve; (4x8 mesh) - 641A4MS55-35
5 lb can of Non-indicating molecular sieve 4A (Ångströms) 3-5 mm bead diameter 4x8 mesh Absorb..
$35.20
55 lb Drum of 4A Non-Indicating Molecular Sieve; (4x8 mesh) - 641A4MS55-35
55 lb can of Non-indicating molecular sieve 3-5 mm bead diameter 4x8 mesh Absorbs molecules as ..
$163.00
1 lb Can of 5A Non-Indicating Molecular Sieve; (8x12 mesh) - 641A5MS01-13
1 lb can of Non-indicating molecular sieve 5A (Ångströms) 1-3 mm bead diameter 8x12 mesh Absor..
$19.95
5 lb Can of 5A Non-Indicating Molecular Sieve; (8x12 mesh) - 641A5MS05-13
5 lb can of Non-indicating molecular sieve 5A (Ångströms) 1-3 mm bead diameter 8x12 mesh Absor..
$37.25
55 lb Drum of 4A Non-Indicating Molecular Sieve; (8x12 mesh) - 641A5MS55-13
55 lb can of Non-indicating molecular sieve 5A (Ångströms) 1-3 mm bead diameter 8x12 mesh Abso..
$192.00
1 lb Can of 13X Non-Indicating Molecular Sieve; (8x12 mesh) - 641X13MS01-13
1 lb can of Non-indicating molecular sieve 13X has pore size of roughly 10 Ångströms 1-3 mm b..
$19.95
5 lb Can of 13X Non-Indicating Molecular Sieve (8x12 mesh); - 641X13MS05-13
5 lb can of Non-indicating molecular sieve 13X has pore size of roughly 10 Ångströms 1-3 mm b..
$37.25
55 lb Drum of 4A Non-Indicating Molecular Sieve; (8x12 mesh) - 641X13MS55-13
55 lb can of Non-indicating molecular sieve 13X has pore size of roughly 10 Ångströms 1-3 mm ..
$192.00
1 lb Can of 13X Non-Indicating Molecular Sieve; (4x8 mesh) - 641X13MS01-35
1 lb can of Non-indicating molecular sieve 13X has pore size of roughly 10 Ångströms 3-5 mm b..
$19.95
5 lb Can of 13X Non-Indicating Molecular Sieve (4x8 mesh) - 641X13MS05-35
5 lb can of Non-indicating molecular sieve 13X has pore size of roughly 10 Ångströms 3-5 mm b..
$37.25
55 lb Drum of 13X Non-Indicating Molecular Sieve; (4x8 mesh) - 641X13MS55-35
55 lb can of Non-indicating molecular sieve 13X has pore size of roughly 10 Ångströms 3-5 mm ..
$192.00
5 lb can of 3A Indicating Molecular Sieve; (4x8 mesh) - 641IMS05
5lb can of indicating molecular sieve 3A (Ångströms) 2-5mm bead diameter 4x8 mesh ​Purchase ..
$87.10
55 lb Drum of 4A Indicating Molecular Sieve; (4x8 mesh) - 641IMS55
55 lb drum indicating molecular sieve 4A (Ångströms) 3-5mm bead diameter 4x8 mesh ​Purc..
$735.65