What is the bulk density of 4A molecular sieve?
As an adsorption desiccant, 4A molecular sieve is used more frequently. What is the bulk density of 4A molecular sieves? 4A molecular sieve spheroids and bars.
4a Molecular sieve strips have a diameter of 1.5-1.7mm, a bulk density of ≥0.66g/ml, a diameter of 3.0-3.3mm, and a bulk density of ≥0.66g/ml;
4a Molecular sieve spherical diameter 1.7-2.5mm, bulk density ≥0.7g/ml, diameter 3.0-3.3mm, bulk density ≥0.7g/ml;
Parameters also include particle size qualification, wear rate, compressive strength, static water adsorption rate, formaldehyde adsorption rate, packaging water content, etc.
4a molecular sieve can adsorb water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, propylene, etc., and does not adsorb any molecules with a diameter larger than 4A (including propane), and its adsorption performance for water is better than any other molecular sieves. It is an industrial Molecular sieve varieties with a larger dosage. 110°C is ok for the evaporation of water in the atmosphere, but the water in the molecular sieve cannot be discharged. Therefore, in the laboratory, it can be activated and dehydrated by drying in a muffle furnace. The temperature is 350°C. Dry under normal pressure for 8 hours (if there is a vacuum pump, it can be dried at 150°C with air extraction). The activated molecular sieve is cooled to about 200°C in air (about 2 minutes), that is, it should be stored in a dry place immediately. If possible, use dry nitrogen to protect the device after use to prevent pollutants from reappearing in the air. The activated 4a molecular sieve should be cooled to about 200°C (about 2 minutes) in the air, that is, it should be stored immediately. .
Influence of Si/Al Ratio of Molecular Sieve
Below 100 is low silicon to aluminum ratio, 100-200 is medium silicon to aluminum ratio. More than 200 is high silicon. The higher the ratio of silicon to aluminum, the better the thermal stability and thermal conductivity, and the weaker the acidity. The aluminum-containing molecular sieve has surface acidity. The reason for its acidity is that Al is trivalent, while Si is tetravalent. Yes, there is a pair of charges on the three-coordinated aluminum, which is the source of the L acid of the molecular sieve. If in order to balance the charges, a hydroxyl group is attached to the aluminum, which becomes the source of the B acid.
The silica-alumina ratio of molecular sieves can strongly affect its acid properties, that is, acid content and acid strength. If the ratio of silicon to aluminum is increased, there will be more silicon, the amount of acid will be reduced, and the acid strength will be increased at the same time.
Molecular sieves use sodium salts in the synthesis process, so the formed molecular sieves are Na-type first, and H-type can be obtained after NH4+ ion exchange and roasting. H-type molecular sieves have a large amount of B acid. Therefore, the Si/Al ratio has a decisive influence on the acid-catalyzed reaction.
4a Molecular sieve strips have a diameter of 1.5-1.7mm, a bulk density of ≥0.66g/ml, a diameter of 3.0-3.3mm, and a bulk density of ≥0.66g/ml;
4a Molecular sieve spherical diameter 1.7-2.5mm, bulk density ≥0.7g/ml, diameter 3.0-3.3mm, bulk density ≥0.7g/ml;
Parameters also include particle size qualification, wear rate, compressive strength, static water adsorption rate, formaldehyde adsorption rate, packaging water content, etc.
4a molecular sieve can adsorb water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, propylene, etc., and does not adsorb any molecules with a diameter larger than 4A (including propane), and its adsorption performance for water is better than any other molecular sieves. It is an industrial Molecular sieve varieties with a larger dosage. 110°C is ok for the evaporation of water in the atmosphere, but the water in the molecular sieve cannot be discharged. Therefore, in the laboratory, it can be activated and dehydrated by drying in a muffle furnace. The temperature is 350°C. Dry under normal pressure for 8 hours (if there is a vacuum pump, it can be dried at 150°C with air extraction). The activated molecular sieve is cooled to about 200°C in air (about 2 minutes), that is, it should be stored in a dry place immediately. If possible, use dry nitrogen to protect the device after use to prevent pollutants from reappearing in the air. The activated 4a molecular sieve should be cooled to about 200°C (about 2 minutes) in the air, that is, it should be stored immediately. .
Influence of Si/Al Ratio of Molecular Sieve
Below 100 is low silicon to aluminum ratio, 100-200 is medium silicon to aluminum ratio. More than 200 is high silicon. The higher the ratio of silicon to aluminum, the better the thermal stability and thermal conductivity, and the weaker the acidity. The aluminum-containing molecular sieve has surface acidity. The reason for its acidity is that Al is trivalent, while Si is tetravalent. Yes, there is a pair of charges on the three-coordinated aluminum, which is the source of the L acid of the molecular sieve. If in order to balance the charges, a hydroxyl group is attached to the aluminum, which becomes the source of the B acid.
The silica-alumina ratio of molecular sieves can strongly affect its acid properties, that is, acid content and acid strength. If the ratio of silicon to aluminum is increased, there will be more silicon, the amount of acid will be reduced, and the acid strength will be increased at the same time.
Molecular sieves use sodium salts in the synthesis process, so the formed molecular sieves are Na-type first, and H-type can be obtained after NH4+ ion exchange and roasting. H-type molecular sieves have a large amount of B acid. Therefore, the Si/Al ratio has a decisive influence on the acid-catalyzed reaction.
