Catalytic cracking of 1, 3, 5-triisopropylbenzene over silicoaluminophosphate with hierarchical pore structure

Abstract

In order to prepare a highly active catalyst for the catalytic cracking of larger molecules, a novel micromesoporous silicoaluminophosphate composite (define as mesoporous SAPO-5) with hierarchical tri-modal pore size distributions has been firstly synthesized via post-synthetic method in acidic condition and subsequently characterized. Morphology control of the composite is attempted by adjusting pH value of the synthetic system. Three different morphologies of composite, including sphere-, rod-and net-like, are obtained in the different conditions. Possible mechanism for the formation of mesoporous SAPO-5 has been proposed. The mesoporous SAPO-5 exhibits higher cracking activity than conventional microporous SAPO-5 for cracking of 1, 3, 5-triisopropylbenzene (1, 3, 5-TIPB) under the same reaction conditions. The result indicates that the mesoporous SAPO-5 with hierarchical pore structure is favorable for catalytic cracking of large molecule. When the cumene as the reaction molecule, the microporous SAPO-5 catalyst exhibits higher conversion in catalytic cracking of cumene compared to the mesoporous SAPO-5, and the result may be attributed to that microporous SAPO-5 has much stronger acidity and specific selectivity than mesoporous SAPO-5 catalyst in catalytic cracking of cumene. Meanwhile, corresponding carbenium ion mechanism can account for the products formed during the whole reaction process.

Cellulose nanocrystals (CNCs) as hard templates for preparing mesoporous zeolite Y assemblies with high catalytic activity

“…To demonstrate the application potential of the Y assemblies templated by CNCs for heavy distillate conversion, the catalytic cracking performance of CNCs-Y with reference to the pristine Y and CNTs-Y was assessed using a pulse method. 33,35,41,42 1,3,5-Triisopropylbenzene (TiPBz), a typical compound to study the dealkylation reactions over FCC catalysts, [41][42][43][44][45] was used as the bulky model molecule. TiPBz has a critical diameter of 0.95 nm, 45 being larger than the intrinsic pore width of FAU Y (i.e.…”

“…Catalytic cracking of 1,3,5-triisopropylbenzene (TiPBz) over Y zeolites (250 mesh pellets) was performed at 325°C under atmospheric pressure using a pulse method. [32][33][34][35] In a catalytic experiment, 20 mg of zeolite catalysts was packed in a borosilicate glasstube liner (internal diameter, i.d. = 4 mm; outer diameter, o.d.…”

Bulk and composite catalysts combining BEA topology and mesoporosity for the valorisation of furfural

“…[37][38][39][40][41][42][43] This approach is interesting for preparing catalyst formulations in which the mesoporous phase acts as an inorganic binder of nanocrystallites, provides a somewhat regular network of mesoporous channels for facilitated mass transport of reagents/products and active sites accessibility. This approach has been used to prepare composites of several zeolites (Beta, 38,40,42,[44][45][46][47][48][49][50][51][52][53] Y, [54][55][56] L, [57][58][59] A, 60,61 , ZSM-5 34,35,39,48,[62][63][64][65][66][67][68] , MCM-22 69 ) or zeotypes (SAPO-5, 70,71 silicalite-1 72 ) embedded in mesoporous siliceous phases. The structure of the mesoporous component depends partly on the type and concentration of the templating agent used: e.g.…”

Synthesis method for introducing mesoporosity in a faujasitic-like zeolite system from a sodium aluminosilicate gel composition

“…The mesoporosity of the CG 40 -50C4d-100C sample leads to an altered chemical reactivity of 1,3,5-TIPB as compared to the microporous only sample RG-100C. Cracking of 1,3,5-TIPB has been extensively studied, and the major reaction pathway occurs via consecutive loss of propyl groups to form the dialkylated products, cumene, benzene and propylene, as well as coke [40][41][42][43]. The conversions increased as a function of reaction temperatures for both CG 40 -50C4d-100C and RG-100C samples, though the conversion level was higher for CG 40 -50C4d-100C (e.g.…”