International Journal of Advanced Engineering Research and Science (IJAERS) [Vol-7, Issue-6, Jun- 2020] https://dx.doi.org/10.22161/ijaers.76.24 ISSN: 2349-6495(P) | 2456-1908(O) www.ijaers.com Page | 194 Cheap zeolite catalyst (Na 3 PO 4 /NaX) for toluene/methanol side chain alkylation Faraz Ahmad 1,# , Yueli Wen 2,# , Bin Wang 1* , Chunyao Hao 1 , Walzli Yousaf 2 , Yuhua Liu 1 , Wei Huang 1,3* 1 Key Laboratory of Coal Science and Technology, Taiyuan University of Technology, Ministry of Education and Shanxi Province, Taiyuan, 030024, Shanxi, China. 2 College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi, China. 3 Coal Conversion Technology & Engineering Co., Ltd., Taiyuan University of Technology, Taiyuan, 030024, Shanxi, China. #Faraz Ahmad and Yueli Wen are co-first authors who have equally contributed to this work. *Corresponding author Email address: wangbin@tyut.edu.cn (Bin Wang); huangwei@tyut.edu.cn (Wei Huang) Abstract— A new zeolite catalyst (Na3PO4/NaX), which is low in cost, environment-friendly and also gives higher conversion of methanol, was prepared by the impregnation method and catalytic performance was tested for side-chain alkylation of toluene with methanol. From the characterization of the catalysts by Temperature-programmed desorption (TPD-CO2), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) method we found that when the concentration of Na3PO4 was 0.1 mol/L, the yield of styrene and ethylbenzene, and conversion of methanol reached 39.4% and 100%. It was determined that as the loading of Na3PO4 onto the NaX surface enhanced, the amount and the strength of middle base sites significantly increased, which is favorable for the toluene/methanol side chain alkylation. Keywords— zeolite catalyst, side-chain alkylation, middle base sites, styrene. I. INTRODUCTION Styrene is a significant chemical material that might be used to produce a wide range of polymers that are utilized in many applications, including toys, food packaging, medical equipment, and paper coverings [1]. Sidorenko et al. first reported styrene production by toluene/methanol side-chain alkylation [2]. Since then, this reaction has involved wide-ranging attention because this method of producing styrene offered economic benefits [3,4] and was supposed as a reliable one step substitute for the existing two-step method over alkylation of benzene with ethylene and followed by the catalytic dehydrogenation of ethylbenzene [5,6]. Many scientists have explored the mechanism of toluene/methanol side-chain alkylation reaction to invent an efficient catalyst for the toluene/methanol side chain alkylation [7]. It is usually recognized that the alkylation of toluene with methanol over basic zeolites can catalyze side-chain alkylation while acidic zeolites can catalyze to the ring of toluene [8]. Toluene/methanol side chain alkylation is a well-known acid-base synergistic catalysis process [9-11]. Usually, acidic sites can stabilize and adsorb toluene; however the function of base sites is to trigger the carbon atom of the side chain of toluene followed by the methanol to formaldehyde dehydrogenation. Formaldehyde formed by the dehydrogenation of methanol acts as an actual alkylating agent for side-chain alkylation [12] and it can decompose into CO and H2 on-basic sites [13,14]. A series of side reactions occur during toluene/methanol side chain alkylation process. Ethylbenzene was supposed to produce through the hydrogenation of styrene with hydrogen, which in turn produced by methanol dehydrogenation to formaldehyde and auxiliary formaldehyde decomposition [15]. It was suggested from previous research that the main reaction pathway for ethylbenzene formation is the hydrogenation of styrene with methanol [16]. Besides xylene formed through toluene disproportionation during the ring alkylation with methanol that existed at acid sites must not be ignored either [17]. There has been extensive study of catalysts for toluene/methanol side chain alkylation [18]. A noble catalyst for toluene/methanol side-chain alkylation was reported to have the following characteristics (1) appropriate strength of base to dehydrogenate methanol to formaldehyde, (2) polarization and stabilization of methyl group of adsorbed toluene, and (3) balanced reactant sorption stoichiometry [3,19]. From previous studies it was found that the catalyst prepared by CsX modified by K3PO4 could enhance the amount and strength of the