Small Grains Nay Zeolite Synthesis

Factors affecting the synthesis of NaY zeolite with traditoinal method is investigated firstly.The result shows that more little gel particles can be earned when it is below 20癈.At longer aging time, more nucleation will be get, but when it is more than four days, the diameter of NaY can not get smaller. The crystallization temperature has an important effect on the synthesis NaY zeolite. When crystallization temperature is 80C, the gel keep amorphous, however when it is 100C, some NaY would turns to P zeolite. In order to make absolute NaY zeolite, better choice is 90C.In this paper, two methods of synthesis of NaY zeolite were reported based on the traditionally synthetic method. One is to add some acetate as chelate ligand, wich would accelerate both nucleation and crystal growth in its deprotonated form. The other is in the presence of a little a mount of Tween series as nonionic surfactants, the diameter of NaY can be decreased By adding some amount of acetate to the synthesis mlcrosized NaY system. The reason is that acetate and hydroxyl would react with aluminosilicate gels and increase aluminate concentration in the liquid phase. Additional aluminate species id favorable to nucleation. however too much acetate would decrease PH of the system and do harm to microsized NaY zeolite. The proper amount of acetate is about n(acetate)/n (Al2O3) =1.5. Tween series would be saponified under the high PH of system and changed into polyoxyethylene sorbitol anhydride and hard soap, polyoxyethylene sorbitol anhydride has hydrophilic head group containing PEO chains which are stongly hydrophlic and benefical for syntehsis of microsized NaY. Hard soap can help decrease the viscosity of aluminosiliate gel and reduce the surface energy of little particles. During the period of crystallization, Compared tween 20, tween 60 and tween 80 with tween20, hard soap of them would react with aluminum ion of the system and changed into undissolved aluminum soap which have little effect on decreasing the diameter of NaY. It can be concluded that tween 20 is the best choice.The proper amount of tweeen20 is about n(tween20)/n((Al2O3)=0.2%~0.3%,and the size of NaY is about 75nm.Catalytic performances of NaY zeolite are investigated in the cracking of diisopropylbenzene as probe reaction. On the cracking of diisopropylbenzene, Evaluation of catalytic activity of all zeolites with different size after ion exchange with rare-earth ions, hydrothermal treatment and calcination has been carried out.