Effect of contributing factors on microwave-assisted hydrothermal synthesis of nanosized SAPO-34 molecular sieves

Dual-template synthesis of nanostructured CoAPSO-34 used in methanol to olefins: Effect of template combinations on catalytic performance and coke formation

“…It is obvious that the corresponding diffractive peaks of all three samples agree well with previously reported patterns of SAPO-34 rhombohedra structure (JCPDS 01-087-1527) [7,9,12,25,27,42,43]. The mentioned structure is isomorphs to the 8 natural zeolite chabazite with the most intense peaks at 2θ = 9.4, 12.9, 20.5 and 30.5.…”

“…In the presented research, total specific surface area (SSA) was measured on apparatus 12 using N 2 adsorption-desorption at 77 K. The Brunauer-Emmett-Teller (BET) equation was used to calculate specific surface area, S BET as reported in Figure 10 for the synthesized samples. It is obvious that the use of TEAOH/DEA and TEAOH/morpholine mixtures caused the increase of SSA comparing to the one prepared with TEAOH/TEA mixed template.…”

“…Among several alternatives, the conversion of methanol to short chain olefins (MTO) has long been of great interest in the petrochemical industry as a potential means of providing demanded olefins in the future when crude oil becomes more expensive [4][5][6][7][8][9][10]. Methanol is one of the largest chemical commodities that can be produced from natural gas, biomass, or from coal via synthesis gas [3,[11][12][13]. In addition, MTO process has a remarkable advantage in terms of product selectivity stemming from its use of zeolite or zeolite-type catalysts [14][15][16][17].…”

Methanol to olefins: activity and stability of nanosized SAPO-34 molecular sieves and control of selectivity by silicon distribution

“…An increase in rate of diffusion can be achieved by preparing CHA type materials with smaller crystalline size. For doing that, a dry gel synthesis method 15 , the use of a combination of different SDA [16][17][18][19] , as well as the use of microwaves 20,21 has been applied to the synthesis of SAPO-34 with the objective of enhancing lifetime of the catalyst for the reaction of methanol to olefins. It has been found that a combination of TEAOH and morpholine in the synthesis results in a decrease of the size of the crystals with the corresponding increase in lifetime 17 .…”

Facile synthesis of SAPO-34 with small crystal size for conversion of methanol to olefins

“…Hydrothermal method, as the conventional strategy, has been applied in the preparation of SAPO-34 by numerous researchers [4][5][6][7][8][9][10][11][12][13][14][15]. However, separation between solvents and solid products is required by filtration or centrifugation, and partial organic SDAs are inevitably preserved in the liquid phase, resulting in the wastewater pollutants and downstream purification system installation [16].…”