Molecular Sieves |
Molecular Sieves are crystalline synthetic zeolites with crystal lattice structures that contain numerous cavities connected by pores with exactly defined diameters. They are suitable for drying practically all gases and liquids. Common uses include desiccators, drying tubes, filling columns, for drying gases and solvents and for keeping absolute solvents dry.
Type | Cat. No. | Size | Composition | Application for Organic Liquids | Application for Gases |
---|---|---|---|---|---|
3A | MX1583A MX1583C MX1583D |
1/16 Pellets 4-8 Mesh Beads 8-12 Mesh Bead |
Potassium Ion with pore diameter of 3 Å (0.3nm) | Acetone, Acetonitrile, Methanol, Ethanol, 2-Propanol | Acetylene, Carbon Dioxide, Ammonia, Propylene, Butadiene, Cracked Gas, Karl Fischer Titrator Drying Tubes |
4A | MX1583G MX1583J MX1583L |
1/16 Beads 4-8 Mesh Beads 8-12 Mesh Beads |
Sodium Ion with pore diameter of 4 Å (0.4nm) | Chloroform, Dichloromethane, Diethyl Ether, Dimethylformamide, Ethyl Acetate, Cyclohexane, Benzene, Toluene, Xylene, Pyridine, Diisopropyl Ether | Natural Gas, Low pressure Air Drying, Karl Fischer Titrator Drying Tubes |
Molecular Sieves can be used to separate molecules based on their different molecular diameters. Since the hollow spaces in which adsorption takes place are only accessible through precisely dimensioned pores, only those molecules will be absorbed that have a critical molecular diameter smaller than that of the pores (sieve effect). The table below lists critical molecular diameters (in nm) for a number of important molecules.
Acetylene | 0.24 | Chlorine | 0.82 | Methanol | 0.44 |
Ammonia | 0.36 | Chloroform | 0.69 | Nitrogen | 0.30 |
Argon | 0.38 | Cyclohexane | 0.69 | Oxygen | 0.28 |
Benzene | 0.67 | Ethane | 0.44 | Propane | 0.49 |
1,3-Butadiene | 0.52 | Ethanol | 0.44 | Propylene | 0.50 |
i-Butane | 0.56 | Ethylene | 0.42 | Toluene | 0.67 |
n-Butane | 0.49 | Ethylene oxide | 0.42 | Triethylamine | 0.84 |
Butene | 0.51 | Hydrogen | 0.24 | Water | 0.28 |
Carbon dioxide | 0.28 | Hellium | 0.20 | m-Xylene | 0.71 |
Carbon monoxide | 0.28 | Hydrogen disulfide | 0.36 | o-Xylene | 0.74 |
Carbon tetrachloride | 0.69 | Methane | 0.40 | p-Xylene | 0.67 |