Synthesis Of Zeolites In The Absence Of Organic Template

Zeolites, especially aluminosilicate zeolites, have been widely applied in the petroleum catalysis and refining industry, and most of industrial applications require these zeolites with a low cost and friendly to the environment. However, modern synthesis methodologies are generally used by organic templates called structure-directing agents (SDA) for their synthesis, which has obvious disadvantages such as relatively high-cost of organic templates and environmentally unfriendly gas formed by the removal of organic templates calcined at high temperature. Therefore, organic template free synthesis and even recycling organic template synthesis of zeolites have been paid much attention recently.zeolites of ZSM-34 and ECR-1 are successfully synthesized in the absence of organic templates for the first time in this paper.In this paper, ZSM-34 zeolite was hydrothermally synthesized at the temperature of 100°C for 7-17 days with molar ratios of starting gels in the presence of zeolite L seeds solution in the absence of template. ZSM-34 zeolite was firstly discovered by Rubin et al using organic template of choline [(CH₃)₃NCH₂CH₂OH], and later ZSM-34 samples were successfully synthesized in the presence of different diamines (NH₂C_nH_2nNH₂, n=4, 6, 8, 10) with different Si/Al ratio. However, these organic templates with relatively high cost in the synthesis severely hinder the practical applications of ZSM-34 zeolite in catalytic reactions. Furthermore, ZSM-34 zeolite which was synthesized with the template was calcined at 500°C in order to remove the organic template in the pore of zeolite. Then it will be regared as catalyst in the industry. However, when we remove the organic template with the calcination, the incomplete pyrogenation maybe result to the block which reduce the catalytic activation obviously. Furthermore,in other aspects, the use of organic template in the synthesis of ZSM-34 zeolite is not available, such as, the expense of calcination and atmosphere pollution during the pyrogenation.In this paper, we provide a novel route for organic template free synthesis of aluminosilicate zeolite of ZSM-34 which is successfully synthesized from an assistance of zeolite L seeds solution. ZSM-34 zeolite has high crystallinity, furthermore, it solves the problem of toxicity and the high price of organic template.Large-pore aluminosilicate zeolite of ECR-1 is an intimate twin of the mordenite-like sheets between layers of mazzitelike cages, which was first discovered by Leonowicz and Vaughan using the organic template of bis(2-hydroxyethyl)-dimethylammonium chloride. Later, ECR-1 is successfully synthesized in the presence of adamantine-containing diquaternary alkylammonium iodides20 or in the presence of tetramethylammonium . In these cases, organic templates in the synthesis of ECR-1 are necessary. However, these organic templates with relatively high cost in the synthesis severely hinder the practical applications of ECR-1 in catalytic reactions for the petroleum industry. We demonstrate a successful organic template free synthesis of the large-pore aluminosilicate zeolite of ECR-1 by carefully adjusting the molar ratio of Na₂O/SiO₂ in the synthesis for the first time.In this paper, we provide a novel route for organic template free synthesis of aluminosilicate zeolites,furthermore, it greatly reduces the production cost of zeolites of ZSM-34 and ECR-1 and decreases the pollution. These will increase their prospect of industry.