VIETNAM NATIONAL UNIVERSITY HOCHIMINH CITY HOCHIMINH CITY UNIVERSITY OF TECHNOLOGY TRAN BA LUAN SYNTHESIS AND MODIFICATION OF Zr-SBA-16 AS CATALYST FOR ALKYLATION REACTION ( TỔNG HỢP VÀ BIẾN TÍNH Zr-SBA-16 LÀM XÚC TÁC PHẢN ỨNG ALKYL HÓA ) Major : Chemical Engineering Code : 605275 MASTER’S THESIS HO CHI MINH CITY JULY 2013 CÔNG TRÌNH ĐƯỢC HOÀN THÀNH TẠI TRƯỜNG ĐẠI HỌC BÁCH KHOA –ĐHQG -HCM Cán bộ hướng dẫn khoa học : P.Giáo sư – Tiến Sĩ Nguyễn Ngọc Hạnh Cán bộ chấm nhận xét 1 : Tiến sĩ Nguyễn Quang Long Cán bộ chấm nhận xét 2 : Tiến sĩ Lý Cẩm Hùng Luận văn thạc sĩ được bảo vệ tại Trường Đại học Bách Khoa, ĐHQG Tp. HCM ngày 06 tháng 09 năm 2013 Thành phần Hội đồng đánh giá luận văn thạc sĩ gồm: 1. Tiến sĩ Huỳnh Kỳ Phương Hạ 2.GS TS Nguyễn Ngọc Hạnh 3. Tiến sĩ Nguyễn Quang Long 4.
Tiến sĩ Lý Cẩm Hùng 5. Tiến sĩ Hồ Quốc Phong Xác nhận của Chủ tịch Hội đồng đánh giá LV và Trưởng Khoa quản lý chuyên ngành sau khi luận văn đã được sửa chữa (nếu có). CHỦ TỊCH HỘI ĐỒNG TRƯỞNG KHOA VIETNAM NATIONAL UNIVERSITY SOCIALIST REPUBLIC OF VIETNAM HOCHIMINH CITY Independence -Freedom - Happiness HOCHIMINH CITY UNIVERSITY OF TECHNOLOGY MISSION MASTER’S THESIS Full name: Tran Ba Luan Student number: 11880184 Date of birth : 07/08/1978 Place of birth: Vinh Long Major : Chemical Engineering Code : 605275 I. TITLE NAME Synthesis and modification of Zr-SBA-16 as catalyst for alkylation reaction (Tổng hợp và biến tính Zr-SBA-16 làm xúc tác phản ứng alkyl hóa) II.
MISSION AND CONTENT: - Literature reviews - Synthesis of Zr-SBA-16. - Modification of Zr-SBA-16 by chloride compound. - Characterization of as-prepared materials. - Study of their catalytic activity on the Friedel-Crafts alkylation of toluene.
START DATE : 21/01/2013 IV. Nguyen Ngoc Hanh Ho Chi Minh City- 31st, July, 2013 SUPERVISOR HEAD OF TRAINNING DEPARTMENT DEAN OF FACULTY ACKNOWLEDMENT First and foremost I offer my sincerest gratithude to my supervisor, Prof Nguyen Ngoc Hanh, who has supported me thoughout my thesis with her patience, motivation, enthusiasm and immense knowledge. Her guidance helped me in all the time of research and writing of this thesis. Besides my advisor, I would like to thank teachers in Faculty of Chemical Engineering, HoChiminh City University of Technology for helping me in encouragement, insightful comments.
Last but not the least; I would like to thank my family supporting me spiritual throughtout my life. Tran Ba Luan ABSTRACT Chloride-promoted zirconium was supported on mesoporous pure silica SBA- 16 (abbreviated Cl-Zr/SBA-16). It was prepared by direct wet impregnation and reflux methods, followed by thermal decomposition. The as-prepared materials were characterised by TDP-NH3, XRD, FT-IR spectroscopy, TEM and SEM images, ICP analysis and nitrogen adsorption-desorption measurements.
The results showed that the 3D cubic arrangement of mesopores corresponding to the Im3hm space group of SBA-16 was retained with the presence of zirconium extra framework about 2% and a change in pore size distribution as well as pore thickness. It could be assumed of restructuration of active sites on internal surface for a potential strong acid catalyst. For application, liquid - phase alkylation of toluene and benzyl chloride to form 1- methyl –4 (phenylmethyl) benzene and 1-methyl –2 (phenylmethyl) benzene using Zr-SBA-16 and Cl-Zr-SBA-16 as catalyst were investigated. The influence of reaction parameters such as reactant ratio, temperature, time.
In this work, the optimum conditions for the alkylation reaction were found to be 0.2g catalyst and volume ratio of toluene and benzyl chloride of 1:1 at 110 oC. After 6 hrs, this reaction reached approximately 71% of conversion with a selectivity of 54 % of the main product. This catalyst could be reused for several cycles with minimal loss of catalyst activity. DECLARATION OF ORGINALITY I hereby declare that this is my own research study.
The research results and conclusions in this dissertation are true, and are not copied from any other resources. The literature references have been quoted with clear citation as requested Dissertation Author Tran Ba Luan TABLE OF CONTENTS LIST OF FIGURES LIST OF TABLES LIST OF ABBREVIATIONS LIST OF PUBLICATIONS CHAPTER 1 - LITERATURE REVIEWS 01 1.1 Introduction of SBA materials 01 1.2 Synthetic mechanism of SBA-16 05 1.2 Modification of SBA materials 09 1.1 Zirconium and its oxide 09 1.2 Modification of SBA by Zr 11 1.3 Introduction of Friedel-Craft alkylation 19 1.1 Friedel-Craft alkylation 19 1.2 Friedel-Craft alkylation using solid acids 21 1.4 Aim and objective 25 CHAPTER 2 – EXPERIMENTAL 27 2.1 Materials and instrumentation 27 2.1 Synthesis of SBA-16 33 2.2 Synthesis of Zr-SBA-16, Cl-Zr-SBA-16 34 2.3 Catalytic studies – The Friedel-Craft alkylation reaction 36 CHAPTER 3 - RESULTS AND DISCUSSION 39 3.1 XRD patterns and Zr content 39 3.2 FT-IR spectra 44 3.3 Nitrogen adsorption/ desorption 47 3.4 Scanning electron microcopy (SEM) and transmission electron microcopy (TEM): 50 3.2 Catalytic activity of Zr-SBA-16 and their derivatives on alkylation 55 3.1 Effect of ratio Zr/Si on reaction conversion 55 3.2 Effect of temperature on reaction conversion 59 3.3 Effect of catalytic contents on reaction conversion 61 3.5 Catalytic recycling studies 67 3.6 Selectivity of products 70 CHAPTER 4 – CONCLUSIONS 80 REFERENCES 83-86 INDEXES LIST OF FIGURES Figure 1.1 Structures of SBA-15 and SBA-16 01 Figure 1.2 Powder X-Ray diffraction of as- synthesized SBA-16 prepared from Na2SiO3.9H2O with surfactants 04 Figure 1.3 Schematic representation synthetic method of SBA-16 06 Figure 1.4 Typical IR spectra of SBA-16 08 Figure 1.5 Typical HRTEM image of SBA-16 09 Figure 1.6 Eight-coordinated structure of SiO2-ZrO2 11 Figure 1.7 Mechanism of MPV reduction and B–V oxidation of carbonyl compounds over supported metal species 12 Figure 1.8 Zr-SBA-15 as an acid catalyst for produring biodiesel 13 Fig 1.9 Effect of reaction temperature (X4) and catalyst loading (X5) on the yield to FAME (Y) for the methanolysis of crude palm oil 14 Figure 1.10 Structure of WO3/Zr-SBA-15 16 2-/ Figure 1.11 Brønsted and Lewis acid site of SO4 ZrO2 16 Figure 1.12 Mechanism of the Friedel-Crafts alkylation reaction 20 Figure 2.1 Architecture of XRD diffractometer 28 Figure 2.2 IUPAC classification of sorption isotherms 30 Figure 2.3 Synthetic scheme of Zr-SBA-16 35 Figure 3.1 Low-angle (a) and large-angle (b) XRD of SBA-16 39 Figure 3.2 Low-angle (a) and large-angle (b) XRD of Zr-SBA-16 40 Figure 3.3 Low-angle (a) and large-angle (b) of XRD of Cl-Zr-SBA-16 40 Figure 3.4 Content of Zr 42 Figure 3.5 IR spectra of SBA-16 44 Figure 3.6 IR spectra of Zr-SBA-16 44 Figure 3.7 IR spectra of Cl-Zr-SBA-16 45 Figure 3.8 Pore size distribution curve of Cl-Zr-SBA-16 46 Figure 3.9 Pore size distribution curve of Zr-SBA-16 47 Figure 3.10 Isotherm profiles of Zr-SBA-16 48 Figure 3.11 Isotherm profiles of Cl-Zr-SBA-16 48 Figure 3.12 Scanning electron microcopy (SEM) of Zr-SBA-16 49 Figure 3.13 Transmission electron microcopy (TEM) of Zr-SBA-16 51 Figure 3.14 NH3-TPD curve of Cl-Zr-10 53 Figure 3.15 NH3-TPD curve of Zr-10 54 Figure 3.16 Reaction conversion on difference of ratio Zr/Si 56 Figure 3.17 Reaction conversion on difference of ratio Zr/Si (impregnated chloride) 58 Figure 3.18 Reaction conversion of Zr-X and Cl-Zr-X 59 Figure 3.19 Reaction conversion of various temperatures 61 Figure 3.20 Reaction conversion on difference of catalytic contents 62 Figure 3.21 Leaching test result of Zr-20 65 Figure 3.22 Reaction conversion on different of reactants and catalyst 66 Figure 3.23 Reaction conversion of normal recycling test 68 Figure 3.24 Reaction conversion of recycling test (impregnated chloride) 69 Figure 3.25 Reaction conversion in comparison of 2 recycling test 70 Figure 3.26 The schematic substitute for toluene 72 Figure 3.27 GC-MS of reaction (using Zr-10) 75 Figure 3.28 GC-MS of reaction (using Cl-Zr-10 ) 77 Figure 3.29 GC-MS of reaction (using Zr-20) 79 LIST OF TABLES Table 1.1 Activity of solid acid catalysts for acylation 17 Table 1.2 BET results of Ga-, Al- and AlGa-SBA-15 mesoporous materials 23 Table 1.3 Activities [total conversion (XT, mol%)] and selectivities of the mesoporous SBA-15 materials in the alkylation of toluene with benzyl chloride 24 Table 1.4 Reusability experiments of Ga-20-A in the alkylation of toluene with benzyl chloride 24 Table 1.5 Activity of Zr-SBA-16 (conversion, mol%) in the Friedel-Crafts alkylation of toluene with benzyl chloride 25 Table 1.6 Conversion (mol%) in the Friedel-Crafts alkylation of toluene with benzyl chloride on Zr-10 and Cl-Zr-10 25 Table 2.1 Table of catalytic studies 38 Table 3.1 Textural properties of the investigated mesoporous materials 46 Table 3.2 Quantitative analysis of ammonia TPD results 52 Table 3.3 Reaction conversion of various ratio of Zr/Si 55 Table 3.4 Reaction conversion of difference ratio of Zr/Si ( impregnated chloride) 56 Table 3.5 Reaction conversion of different temperatures 60 Table 3.6 Reaction conversion of different catalytic contents 62 Table 3.7 Reaction conversion on the first leaching test 64 Table 3.8 Reaction conversions on the second leaching test 65 Table 3.9 Results of the normal recycling test 67 Table 3.10 Results of the second recycling test ( impregnated with chloride) 68 Table 3.11 Selectivity of products 73 LIST OF ABBREVIATIONS ICP Inductively coupled Plasma FR-IR Fourier transform infrared spectroscopy SEM Scanning electron microscopy SBA Mesoporous SBA-type silica materials TEM Transmission electron microscopy TDP-NH3 Temperature-programmed desorption of ammonia XRD X-ray powder diffraction XPS X-ray Photoelectron Spectroscopy Zr-X Zr-SBA-16 with a theoretical Zr/Si, ratio of X%. 1 CHAPTER 1 – LITERATURE REVIEWS 1.1 INTRODUCTION OF SBA MATERIALS 1.1 SBA materials In recent years, there have been many studies about mesoporous silica (MCM-41, MCM-48, SBA-15, SBA-16.) as catalytic support because of their unique properties such as high specific surface area, well-ordered, evenly pore structure for facile dispersion of active component and for diffusion of great size molecules. In addition, they have high activity and selectivity, appropriate acidity and optimal metal support interaction.
Zhao et al. reported the synthesis of a variety of mesoporous SBA-type silica materials (SBA = Santa Barbara Amorph), using non-ionic triblock copolymers as template. This surfactant is very interesting, because it is easily separable, nontoxic, biodegradable, and inexpensive. Typification of the SBA-n-type mesoporous silica materials are SBA-15 and SBA-16.1 Structures of SBA-15 (left) and SBA-16 (right) [26].
SBA-15 materials are prepared under acidic conditions with the triblock copolymer pluronic P123 (EO20PO70EO20) surfactant as template. The 2 mesopores are ordered in hexagonal arrays providing the same long range space group as for MCM-41 materials (P6mm). However, due to the properties of the pluronic type surfactant, SBA-15 materials show up important differences in porosity and adsorption properties compared to MCM-41 materials. In a regular synthesis, SBA-15 materials have much thicker but still amorphous walls and primary mesopore diameters between 5 nm to 15 nm.
The BET surface area of SBA-15 is generally lower than the one of MCM-41. Due to thicker pore walls, it is hydrothermally stable. Also due to the pluronic surfactant type, SBA-15 materials generally have a second intrawall porosity consisting of micropores or smaller mesopores. These unordered pores interconnect the primary mesopore channels.
It is possible to tailor the micro/mesopore ratio to the needs of the application, still conserving the rather thick pore walls. The intrawall microporosity is caused by the penetration of the hydrophobic PO groups of the block copolymer chain into the silica matrix. The thick wall is caused by the length of these polymer chains [4,5]. Among the reported 3-D cubic mesoporous silica materials, SBA-16 appears to be one of the best candidates for catalytic support or absorbent because of the good thermal stability due to thick wall, economical synthesis with inexpensive silica sources, and large pore [4,5,26].
SBA-16 is a porous silica with large pores (5-15 nm) cage-like mesopores arranged in a three dimensional cubic body-centered Im3m symmetry. It is synthesized in acidic conditions, using a nonionic pluronic surfactant (Figure 2.2) and is therefore providing an intrawall complementary porosity [26]. The mesophase can be created using mixtures of pluronic P123 and pluronic F127 (EO106PO70EO106) or in a ternary water, butanol and pluronic F127 system.